WO2024251713A1 - Décomposition catalytique d'ammoniac avec de la vapeur d'eau en tant que milieu de transfert de chaleur - Google Patents

Décomposition catalytique d'ammoniac avec de la vapeur d'eau en tant que milieu de transfert de chaleur Download PDF

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Publication number
WO2024251713A1
WO2024251713A1 PCT/EP2024/065287 EP2024065287W WO2024251713A1 WO 2024251713 A1 WO2024251713 A1 WO 2024251713A1 EP 2024065287 W EP2024065287 W EP 2024065287W WO 2024251713 A1 WO2024251713 A1 WO 2024251713A1
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WO
WIPO (PCT)
Prior art keywords
heat exchanger
heat
water
flue gas
gas
Prior art date
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Pending
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PCT/EP2024/065287
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German (de)
English (en)
Inventor
Alexander Kleyensteiber
Johannes ELISCHEWSKI
Klaus NÖLKER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ThyssenKrupp AG
ThyssenKrupp Industrial Solutions AG
Original Assignee
ThyssenKrupp AG
ThyssenKrupp Uhde GmbH
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Filing date
Publication date
Priority claimed from DE102023114883.4A external-priority patent/DE102023114883A1/de
Priority claimed from LU103144A external-priority patent/LU103144B1/de
Application filed by ThyssenKrupp AG, ThyssenKrupp Uhde GmbH filed Critical ThyssenKrupp AG
Priority to KR1020257043793A priority Critical patent/KR20260018105A/ko
Priority to CN202480050031.XA priority patent/CN121693462A/zh
Publication of WO2024251713A1 publication Critical patent/WO2024251713A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; Reversible storage of hydrogen
    • C01B3/02—Production of hydrogen; Production of gaseous mixtures containing hydrogen
    • C01B3/04—Production of hydrogen; Production of gaseous mixtures containing hydrogen by decomposition of inorganic compounds
    • C01B3/047—Decomposition of ammonia
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; Reversible storage of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen-containing gases from gaseous mixtures, e.g. purification
    • C01B3/508—Separation of hydrogen or hydrogen-containing gases from gaseous mixtures, e.g. purification by using hydrogen storage media
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0266—Processes for making hydrogen or synthesis gas containing a decomposition step
    • C01B2203/0277—Processes for making hydrogen or synthesis gas containing a decomposition step containing a catalytic decomposition step
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/042—Purification by adsorption on solids
    • C01B2203/043—Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08—Methods of heating or cooling
    • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0811—Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08—Methods of heating or cooling
    • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0833—Heating by indirect heat exchange with hot fluids, other than combustion gases, product gases or non-combustive exothermic reaction product gases

Definitions

  • the invention relates to a plant and a method for producing H2 by catalytic decomposition of NH3.
  • Water serves as a heat transfer medium for recovering process heat.
  • the process heat is absorbed by water or steam and then released to NH3, whereby NH3 is heated and evaporated.
  • the use of water or steam as a heat transfer medium has advantages, including in terms of cost-effectiveness and safety.
  • H2 can be obtained from H2O using renewable energy and then converted into NH3 with N2.
  • NH3 can be stored and transported much more safely than H2.
  • NH3 can then be broken down into H2 and N2. After N2 has been separated, H2 finds a wide variety of industrial applications.
  • US 4 704 267 A relates to the production of high purity H2 from liquid, anhydrous NH3.
  • NH3 is vaporized and then split into its components.
  • the resulting dissociated gas stream is fed to an adiabatic metal hydride purification unit to absorb the H2 present in the stream.
  • the adsorbed H2 is then recovered as a high purity product.
  • US 2022/170433 A1 relates to a reforming system comprising an evaporator configured to evaporate liquid fuel to produce fuel gas; a reformer configured to reform the fuel gas produced by the evaporator to produce a reformed gas containing hydrogen; an air supplier configured to supply air to the reformer; a fuel gas supplier configured to supply the fuel gas to the reformer; a heater configured to increase a temperature of the reformer; a reformed gas flow passage through which the reformed gas produced by the reformer flows; a cooler arranged in the reformed gas flow passage and configured to cool the reformed gas; a circulation passage connecting the evaporator to the cooler and through which refrigerant flows through the evaporator and the cooler; and a circulation pump disposed in the circulation passage and configured to circulate the refrigerant through the circulation passage.
  • EP 4 067 298 A1 relates to a method for refueling vehicle tanks with compressed hydrogen, which comprises splitting ammonia into hydrogen and nitrogen in an ammonia cracking plant, compressing the hydrogen from the ammonia cracking plant and delivering the compressed hydrogen to the vehicle tanks in a hydrogen refueling plant having one or more delivery units, wherein cooled ammonia is used to cool the compressed hydrogen prior to delivery to the vehicle tanks by heat exchange between the compressed hydrogen and the cooled ammonia so that the cooled ammonia is heated, and the heated ammonia is transferred to the ammonia cracking unit.
  • FR 1 469 045 A relates to an apparatus comprising a preheater fed with NH3, a tube bundle enclosing a catalyst for splitting NH3 and, optionally, a cell for purifying H2 by diffusion, which are connected to one another and housed in a single housing containing heating means.
  • CN 111 957 270 A relates to an NH3 decomposition apparatus comprising an NH3 decomposition unit and a combustion unit acting on the NH3 decomposition unit.
  • NH3 enters the NH3 decomposition unit via a first purified gas inlet to carry out a decomposition reaction of the NH3.
  • Produced mixed gas is discharged via a second purified gas outlet and then enters the combustion unit via a second purified gas inlet.
  • the mixed gas includes N2, H2 and undecomposed NH3.
  • the mixed gas enters the combustion unit to provide heat for the decomposition reaction of NH3 of the Nfh decomposition unit, so that the self-sufficiency of heat is realized in the NH3 decomposition-H2 production system. No additional fuel is needed for energy supply, and the cost of the NH3 decomposition-H2 production system is reduced.
  • CN 113 896 168 A relates to a process for producing H2 or reducing gas by cracking NH3 with a two-stage process comprising the following steps: the liquid NH3 of the raw material is fully gasified and heated by a heat exchange gasification system and then enters a first-stage heat exchange NH3 cracking reaction system to produce a partial NH3 cracking reaction.
  • the reaction gas from the first-stage heat exchange NfE cracking reaction system enters a second-stage high-temperature NH3 cracking reaction system to perform a residual NH3 cracking reaction.
  • the high-temperature NH3 cracking reaction gas of the second stage enters the first-stage heat-concentrated NPh cracking reaction system and the heat exchange gasification system successively to gradually recover heat, so that the reducing gas is obtained.
  • WO 2001/087770 Al relates to the autothermal decomposition of NH3 to produce high purity H2.
  • WO 2011/107279 A1 relates to an NH3-based H2 production reactor comprising an NFh cracking chamber with an NFh cracking catalyst, an inner combustion chamber with a combustion or oxidation catalyst which is in thermal contact with the NFh cracking chamber, an NFh gas preheating chamber and an outer jacket ring for heat recovery from the combustion products emerging from the combustion chamber, wherein the cracking chamber, the inner combustion chamber, the preheating chamber and the heat recovery jacket ring are arranged concentrically.
  • WO 2017/160154 A1 relates to a method for generating power using a gas turbine, comprising the following steps: (i) vaporizing and preheating liquid NH3 to produce preheated NH3 gas; (ii) introducing the preheated NH3 gas into an NH3 cracking device suitable for converting NH3 gas into a mixture of H2 and N2; (iii) converting the preheated NH3 gas into a mixture of H2 and N2 in the device; (iv) cooling the mixture of H2 and N2 to obtain a cooled H2 and N2 mixture; (v) introducing the cooled H2 and N2 mixture into a gas turbine; and (vi) combusting the cooled H2 and N2 mixture in the gas turbine to generate power.
  • WO 2019/038251 A1 relates to a process for producing a product gas containing N2 and H2 from NH3, comprising the steps of non-catalytic partial oxidation of NH3 with an O2-containing gas to a process gas containing N2, water, amounts of nitrogen oxides and residual amounts of NH3; cracking at least a portion of the residual amounts of NH3 to H2 and N2 in the process gas by contact with a nickel-containing catalyst and simultaneously reducing the amounts of nitrogen oxides to N2 and water by reaction with a portion of the H2 formed during cracking of the process gas by contact of the process gas with the nickel-containing catalyst; and withdrawing the product gas containing H2 and N2.
  • WO 2012/039183 A1 relates to an NH3 decomposition device that generates H2 as a combustion enhancer and an NH3 oxidation device that reacts a portion of the introduced NH3 with O2 using an oxidation catalyst, causing combustion to provide the heat required for an NH3 decomposition reaction.
  • WO 2012/090739 A1 relates to a Th generator comprising a decomposition device that decomposes a compound containing an H atom and an N atom and generates H2; a compound supply device that supplies the compound to the decomposition device; and an O2 supply device that supplies O2 to the decomposition device.
  • WO 2020/095467 A relates to an apparatus for generating fP gas comprising: an NH3 evaporator that heats liquid NH3 to generate NfE gas; a main thermal decomposition device that causes combustion of a fuel gas, thereby heating the NfE gas generated by the NH3 evaporator and decomposing it into N2 gas and H2 gas; a cooler that cools a decomposition-generated gas containing the N2 gas and the H2 gas generated by the decomposition by the main thermal decomposition device; and a separator that separates the H2 gas from the cooled decomposition-generated gas.
  • WO 2021/257944 A1 relates to the recovery of H2 from an NH3 cracking process in which the cracking gas is purified in a PSA device.
  • the use of a membrane separator for the PSA exhaust gas improves the recovery.
  • WO 2022/096529 A1 relates to a process for cracking NH3, producing H2 and generating electric power, comprising electrolysis of water in supplied NH3, evaporation, preheating and cracking NH3 using NfE-synthcsc catalysts at low temperatures.
  • WO 2022/243410 A1 relates to a process for the synthesis of H2 via the catalytic cracking of NH3; wherein a NfE-containing stream is subjected to a catalytic cracking step in the presence of heat to obtain a combusted gas and a thermally cracked stream containing N2, H2 and possibly residual NH3 and optionally water; wherein the thermally cracked stream is subjected to a H2 recovery step to obtain a high purity H2 stream.
  • WO 2022/265647 A1 relates to the recovery of a renewable H2 product from an NHs cracking process in which the cracked gas is purified in a first PSA device and at least part of the first PSA tail gas is recycled as fuel to reduce the carbon intensity of the renewable EE product.
  • WO 2022/265648 A1 relates to the removal of NOx contaminants by selective catalytic reduction (SCR) from a flue gas produced in an NH3 cracking process using an aqueous NHs solution produced by cooling the compressed exhaust gas from an H2-PSA device to purify the cracked gas.
  • SCR selective catalytic reduction
  • WO 2022/265649 A1 relates to the reduction of the water content of the NH3 used in an NFF cracking process, thereby enabling the use of water-incompatible cracking catalysts.
  • the process of water removal can also be used to recover and recycle NH3 from the cracking gas.
  • WO 2022/265650 A1 relates to a NEE fission process in which fission gas is purified in a PSA system. Residual NH3 in a first fission gas is converted into further H2 and N2 by feeding PSA residual gas or a gas derived therefrom to a secondary fission reactor and further processing a second fission gas.
  • WO 2022/265651 A1 relates to a process in which residual NH3 is removed from NH3 cracking gas in an EE-PSA system using a non-zeolitic adsorbent such as activated carbon, activated alumina or silica gel.
  • a non-zeolitic adsorbent such as activated carbon, activated alumina or silica gel.
  • WO 2023/144335 A1 relates to a process for producing hydrogen by splitting ammonia, in which ammonia is split into hydrogen and nitrogen in the presence of a catalyst, the splitting of the ammonia taking place without prior non-catalytic oxidation in the absence of an oxidizing agent only by supplying heat in the presence of the catalyst.
  • the splitting of the ammonia is carried out in a reactor (18) analogous to a primary reformer, the catalyst being arranged in at least one tube through which ammonia flows.
  • a mixture of ammonia and hydrogen is preferably burned, the nitrogen formed in the reaction being an inert component that serves as an additional heat carrier.
  • a mixture of hydrogen and ammonia is advantageous because it has a medium flame temperature, better combustion properties than pure ammonia and, depending on the mixing ratio, emits less NOx than the two pure substances.
  • the processes according to the state of the art have safety-related disadvantages.
  • the process gas in the main process line or the flue gas serves as the heat transfer medium for the preheating and evaporation of NH3.
  • NH3 absorbs suitably connected heat exchangers extract heat directly from the process gas or the flue gas.
  • the heat exchanger on the side of the liquid or evaporating NH3 has the higher pressure. If a heat exchanger were to be damaged during such a process, e.g. if a pipe bursts, which can certainly happen in large industrial plants, then NH3 would flow in significant quantities either into the main process line or into the flue gas as a result of the pressure drop.
  • NH3 would then enter the plant for separating H2, e.g. a pressure swing adsorption device.
  • pressure swing adsorption devices can be configured to separate polar substances such as NH3, a significant increase in the applied quantity could lead to a breakdown, which would cause NH3 to enter directly into the product stream.
  • the production of H2 should be safe, economical and possible on an industrial scale.
  • NH3 absorbs heat from heated water or steam in suitably connected heat exchangers and thus passes into the gas phase. If a heat exchanger were to be damaged during the process according to the invention, NH3 would be mixed with the aqueous phase and possibly dissolved therein (approx. 1200 liters of NH3 dissolve in one liter of water at 0°C, and approx. 500 liters of NH3 at 23°C). Any breakthrough into the product gas or flue gas is thus efficiently prevented according to the invention, thereby improving the safety of the process.
  • NH3 is preferably stored cold, e.g. in a tank, and preferably enters the system according to the invention at -33°C. NH3 must be warmed up and evaporated to carry out the catalytic decomposition reaction.
  • medium-pressure steam or its condensate is preferably used to preheat the NH3 to its boiling point and then evaporate it, which are preferably fed in countercurrent to the NH3. This process is advantageous in terms of the safety of the system, since it prevents NFF emissions into the flue gas or process gas in the event of damage to the heat exchanger involved (e.g. due to a pipe burst).
  • water serves as a heat transfer medium for heating and evaporating NH3.
  • NH3 can be present independently of one another in liquid or gaseous form (water vapor, NHs vapor).
  • water vapor NHs vapor
  • steam preferably medium-pressure steam, preferably with a pressure in the range of 10 to 40 bar and with a temperature in the range of about 180°C to about 250°C;
  • liquid warm water preferably with a temperature in the range > 44°C to 90°C;
  • liquid heated cooling water of higher temperature preferably with a temperature in the range of > 32°C to 44°C;
  • liquid heated cooling water of lower temperature preferably having a temperature in the range of 20°C to 32°C.
  • the NH3 entering the plant is cold enough to use the cooling water produced in the plant as a heat source.
  • blowdown is added, which occurs during the generation of water vapor in an H2O evaporation device according to the invention.
  • the invention relates to a plant for producing H2 by catalytic decomposition of NH3 comprising - a combustion device for burning a combustion gas to produce combustion heat and flue gas;
  • an NH3 evaporation device for evaporating liquid NH3 by absorbing heat from heated water, preferably water vapor;
  • an NH3 reduction device for the catalytic decomposition of evaporated NH3 by absorbing combustion heat generated in the combustion device and producing a product gas comprising H2 and N2;
  • a flue gas heat exchanger for heating water, preferably for heating or generating water vapor, by absorbing heat from the flue gas; and/or in the flow direction of the product gas downstream of the NFh combustion device, a product gas heat exchanger for heating water, preferably for heating or generating water vapor, by absorbing heat from the product gas;
  • the plant according to the invention comprises a device for purifying H2, preferably a pressure swing adsorption device.
  • the plant is designed for a throughput based on H2 of at least 500 mol-h 1 , preferably at least 1000 mol-h 1 , more preferably at least 5000 mol-h 1 , even more preferably at least 10,000 mol-h 1 , most preferably at least 50,000 mol-h 1 , and in particular at least 100,000 mol-h 1 .
  • the plant comprises a tank for liquid NH3 which has a volume of at least 50 m 3 , preferably at least 100 m 3 , more preferably at least 500 m 3 , even more preferably at least 1000 m 3 , most preferably at least 5000 m 3 , and in particular at least 10,000 m 3 .
  • the NH3 decomposition device comprises at least three, preferably at least four, more preferably at least five, even more preferably at least six, most preferably at least seven and in particular at least eight catalyst beds, each of which comprises NH3 decomposition catalyst; each catalyst bed is preferably present in a tube; the catalyst beds are preferably connected in parallel.
  • the Nfh reduction device comprises at least one catalyst bed which comprises Nfh reduction catalyst, wherein the length of the catalyst bed in the flow direction for NH3 is at least 1.0 m, preferably at least 1.5 m, more preferably at least 2.0 m, even more preferably at least 2.5 m, most preferably at least 3.0 m and in particular at least 3.5 m; wherein the catalyst bed is preferably present in a tube.
  • the combustion device comprises at least three, preferably at least four, more preferably at least five, even more preferably at least six, most preferably at least seven and in particular at least eight burners for combustion of the combustion gas.
  • the flue gas heat exchanger and/or the product gas heat exchanger is a tube heat exchanger or tube bundle heat exchanger.
  • the system according to the invention comprises a return line and a branching line for the residual gas mixture from the device for purifying H2, preferably a pressure swing adsorption device, to the combustion device.
  • the device for purifying H2 preferably a pressure swing adsorption device
  • the invention also relates to the use of a plant according to the invention for the production of H2.
  • the invention further relates to a process for producing H2 by catalytic decomposition of NH3 comprising the steps:
  • step (d) optionally, heating NH3 by absorbing heat from water obtained by step (e);
  • step (f) catalytic decomposition of NH3 vaporized in step (e) by absorbing combustion heat generated in step (a) and producing a product gas comprising H2 and N2;
  • step (g) heating water, preferably heating or generating water vapor, by absorbing heat from the flue gas generated in step (a) and/or from the product gas; and introducing the heated water or the heated or generated water vapor into step (e).
  • Steps (b), (c) and (d) of the method according to the invention are optional, independently of one another.
  • steps (a) to (g), if implemented, are carried out in alphabetical order.
  • a throughput based on H 2 of at least 500 mol-h 1 is achieved in step (f), preferably at least 1000 mol-h 1 , more preferably at least 5000 mol-h 1 , even more preferably at least 10,000 mol-h 1 , most preferably at least 50,000 mol-h 1 , and in particular at least 100,000 mol-h 1 .
  • step (e) the liquid NH 3 is taken from a tank having a volume of at least 50 m 3 , preferably at least 100 m 3 , more preferably at least 500 m 3 , even more preferably at least 1000 m 3 , most preferably at least 5000 m 3 , and in particular at least 10,000 m 3 .
  • step (f) the catalytic decomposition of NH 2 takes place on at least three, preferably at least four, more preferably at least five, even more preferably at least six, most preferably at least seven and in particular at least eight catalyst beds, each of which comprises NH 3 decomposition catalyst; each catalyst bed is preferably present in a tube; the catalyst beds are preferably flowed through in parallel by NH 3 .
  • step (f) the catalytic decomposition takes place on at least one catalyst bed which comprises NH s decomposition catalyst, wherein the length of the catalyst bed in the flow direction for NH 2 is at least 1.0 m, preferably at least 1.5 m, more preferably at least 2.0 m, even more preferably at least 2.5 m, most preferably at least 3.0 m and in particular at least 3.5 m; wherein the catalyst bed is preferably present in a tube
  • step (a) the combustion of the combustion gas is carried out with the aid of at least three, preferably at least four, more preferably at least five, even more preferably at least six, most preferably at least seven and in particular at least eight burners.
  • the heating in step (g) takes place in a heat exchanger selected from tube heat exchangers and tube bundle heat exchangers.
  • the catalytic decomposition of NHs means the formation of N 2 and H 2 , sometimes also referred to in the prior art as "cleavage” or “cracking" of NH 2 .
  • the catalytic decomposition of NH 2 preferably takes place according to the invention in the absence of O 2 .
  • the invention comprises the following measures:
  • the recovery of heat according to the invention is an essential aspect of the invention because the catalytic decomposition of NH3 takes place at elevated temperature in the gas phase and the resulting residual heat should be used as efficiently as possible for economic and ecological reasons.
  • heat is provided by combustion of a combustion gas in a combustion device.
  • a first part of the heat formed during combustion preferably flows into an NPh reduction device in which the NPh reduction catalyst is present, for example in the form of one or more catalyst beds.
  • the endothermic catalytic decomposition of NH3 takes place there.
  • a second part of the heat formed during combustion preferably leaves the combustion device with the flue gas and enters a flue gas channel.
  • the hot product gas typically represents a larger mass flow than the hot flue gas, but the temperature of the product gas is typically lower than the temperature of the flue gas.
  • heat can be extracted to a suitable extent from the product gas on the one hand and the flue gas on the other, thereby increasing the overall yield.
  • heated water preferably water vapor
  • the water vapor is preferably generated in an FEO evaporation device, which preferably comprises a water vapor drum and a heat exchanger, which are operatively connected to one another.
  • the FEO evaporation device comprises
  • the H2O evaporation device comprises, in addition to the steam drum, the product gas heat exchanger in which water absorbs heat from the product gas.
  • the H2O evaporation device comprises, in addition to the steam drum, the flue gas heat exchanger in which water absorbs heat from the flue gas.
  • the H2O evaporation device comprises, in addition to the steam drum, both the product gas heat exchanger in which water extracts heat from the product gas and the flue gas heat exchanger in which water absorbs heat from the flue gas.
  • boiler feed water is fed to the steam drum. If more boiler feed water is fed in than steam is removed, there is a surplus of heated boiler feed water, which can be separated from the steam and used like other heated cooling water, in particular for heating NH3.
  • heat contained in the hot product gas and/or flue gas is absorbed by the water, whereby water vapor is heated or generated.
  • the water vapor is fed via a pipe system into the NH3 evaporation device, where NH3 absorbs heat from the water vapor, is heated and finally evaporates itself.
  • boiler feed water is preheated in the flue gas duct, then a bypass stream is branched off from it and the remaining remainder of the preheated boiler feed water is fed into the steam drum.
  • no bypass stream is diverted, but the entire amount of preheated boiler feed water is fed into the steam drum.
  • an excess is then discharged from the steam drum in liquid boiling form. In this way, more heat can be extracted from the process gas (flue gas or product gas), which can be advantageous if excess heat is available there.
  • the heated and evaporated NH3 is then heated to an even higher temperature level, as is desirable or necessary for the catalytic decomposition of NH3, and finally fed to the NH3 decomposition device.
  • Additional heat which is required to reach the desired decomposition temperature or to maintain the endothermic catalytic decomposition, is according to the invention preferably supplied directly by a heat flow which flows from the combustion device into the NH s decomposition device.
  • the NH s decomposition device and the combustion device preferably together form a reactor which is designed analogously to a primary reformer.
  • the heat recovery according to the invention can preferably fulfil, for example, the following tasks:
  • heat contained in the flue gas stream of the combustion device and/or heat contained in the product gas stream of the NFh combustion device is used in at least three, preferably in at least four, particularly preferably in at least five heat exchangers arranged one behind the other in the flow direction of the flue gas stream or product gas stream, preferably for different sub-processes of the method.
  • NH3 absorbs heat from water, preferably water vapor, and passes into the gas phase.
  • the temperature of the NH3 when entering the NH3 evaporation device is in the range of about 60 ⁇ 30°C, more preferably about 60 ⁇ 15°C.
  • the temperature of the NH3 when leaving the NFk evaporation device is in the range of about 60 ⁇ 30°C, more preferably about 60 ⁇ 15°C.
  • At least one heat exchanger is arranged downstream of the NFE evaporation device in the direction of flow of the NH3, which is either the product gas heat exchanger or the flue gas heat exchanger.
  • at least two heat exchangers are arranged downstream of the NFE evaporation device in the direction of flow of the NH3, which are the product gas heat exchanger and the flue gas heat exchanger.
  • the heated water, preferably steam, supplied as a heat source for the operation of the NFE evaporation device is generated in the product gas heat exchanger by absorbing heat from the product gas and/or in the flue gas heat exchanger by absorbing heat from the flue gas.
  • the heat in the product gas and/or flue gas is used to heat or generate steam in a H20 evaporation device and this water vapor is fed to the NHs evaporation device.
  • the water vapor optionally in the form of water vapor condensate, is used again after exiting the NH3 evaporation device, namely as a heat medium in NH3 preheating and NH3 evaporation.
  • the preheater is arranged upstream of the NFF evaporation device in the flow direction of the NH3 in order to preheat NH3.
  • NH3 absorbs heat from water, preferably water vapor condensate.
  • the temperature of the NH3 when entering the preheater is in the range of approximately -35 ⁇ 10°C, more preferably approximately -35 ⁇ 5°C.
  • the temperature of the NH3 when leaving the preheater is in the range of approximately 60 ⁇ 30°C, more preferably approximately 60 ⁇ 15°C.
  • the steam flow is preferably set so that essentially only steam condensate leaves the NFE evaporation device.
  • "blowdown" and/or boiler feed water e.g. from a bypass, can be mixed with this steam condensate (see below).
  • generated water vapor and generated water vapor condensate are passed in countercurrent through the preheater and the NFc evaporation device.
  • the NH3 passes through the preheater, where NH3 absorbs heat from water vapor condensate in countercurrent.
  • the energy input is high enough to heat the NH3 to the boiling point and partially evaporate it.
  • at least 5%, more preferably at least 10%, even more preferably at least 15%, most preferably at least 20% and in particular at least 25% of the total flow of NH3 is already evaporated in the preheater.
  • the vapor content of the NH3 can be up to 35%.
  • the preheater preferably contains a device for separating the two NFF phases, so that the remainder of the NH3 which has not yet evaporated enters the NH3 evaporation device at boiling temperature, and the gaseous NH3 is transported in a separate pipeline.
  • both phases of the NH3 can also enter the NH3 evaporation device in a common pipeline.
  • water vapor serves as the heat medium, for example saturated water vapor at 33.5 bar a and a temperature of 239.8°C.
  • the water vapor ensures the complete evaporation of the NH s, preferably again via a device integrated into the heat exchanger for separating the two phases.
  • Both gaseous NH s streams are preferably combined and fed further into the process.
  • heat from heated cooling water is preferably used in addition to heating NH3.
  • Heated cooling water which is preferably used according to the invention for heating NH; is preferably obtained at
  • the yield of H2 is increased by relatively reducing the amount of water vapor produced and the resulting lower heat requirement remains in the process, whereby less combustion gas is required.
  • the energy gap arising with regard to the preheating and evaporation of NH3, which results from the relatively lower amount of water vapor provided, is preferably closed by preheating NH3 with the heated cooling water.
  • a preheating device is preferably arranged in the flow direction of the NH3 downstream of the tank and upstream of the NHs evaporation device, preferably also in the flow direction of the NH3 upstream of the preheater, if present, which preferably serves to preheat the NH3 and in which NH3 absorbs heat from water, which in turn has previously accrued elsewhere as heated cooling water.
  • the heated cooling water is taken from a process cooler in the flow direction of the product gas upstream of a device for purifying H2, preferably a pressure swing adsorption device, where it has previously absorbed heat from the product gas.
  • the heated cooling water is additionally or alternatively taken from a heat exchanger of a possible tB compressor, where it has previously absorbed heat from compressed H2.
  • the heated cooling water is additionally or alternatively taken from a water vapor condensate heat exchanger which is connected downstream of the NH3 evaporation device.
  • heat from the condensed steam is also used, i.e. the steam condensate is cooled before it is returned for processing.
  • a steam condensate heat exchanger is preferably arranged downstream of the NH s evaporation device in the flow direction of the steam condensate.
  • the steam condensate heat exchanger is preferably arranged downstream of the preheater in the flow direction of the steam condensate.
  • the steam condensate then preferably leaves the NH3 evaporation device first and is returned to the preheater, in which NH3 absorbs heat from the steam condensate and is thereby preheated.
  • the steam condensate then enters the steam condensate heat exchanger, in which cooling water absorbs heat from the steam condensate.
  • the cooling water heated in this way can be used elsewhere, for example to preheat liquid NH3.
  • the flue gas can also be cooled with cooling water. This can be useful, for example, if there is no IT compressor and therefore not enough heated cooling water is available to provide the required amount of heat for preheating and evaporating the NH3.
  • the pre-temperature at which fresh, i.e. not yet heated, cooling water is usually supplied depends on the climate of the location.
  • the cooling water removes process heat by heating it by a temperature difference of typically about 8°C to about 15°C.
  • the heat absorbed by the cooling water is then preferably used to preheat liquid NH3 (see Figure 7).
  • the temperature of the cooling water or heated cooling water is thus preferably significantly below the temperature of the water or water vapor which is used in the NH3 evaporation device according to the invention for evaporating NH3.
  • the temperature is preferably temperature of the heated cooling water is at most 100°C, preferably at most 80°C, even more preferably at most 60°C.
  • a cooling water return temperature of about 50°C can be expected, in Central Europe it is more likely to be about 30°C.
  • liquid heated cooling water of higher temperature preferably > 32°C to 44°C
  • liquid heated cooling water of lower temperature preferably 20°C to 32°C
  • liquid heated cooling water of a lower temperature is used to heat NH3
  • the subsequent evaporation of the NH3 heated in this way is then preferably achieved only by heat from the water vapor condensate.
  • liquid heated cooling water at a higher temperature is used to heat NH3, the NH3 can be preheated to significantly higher temperatures.
  • a heat exchanger can be provided in the flue gas duct to absorb heat from the flue gas. This is particularly useful if there is no H2 compressor, so that there is also no heat exchanger downstream of the H2 compressor, in which heated cooling water at a higher temperature would otherwise be produced. Alternatively, such an H2 compressor is present. In this case, a heat exchanger downstream of the H2 compressor or between several H2 compressors preferably provides a sufficient amount of heated cooling water at a higher temperature.
  • heat from water is preferably used, which absorbs heat from the flue gas, then releases this heat to NH3 for preheating, then absorbs heat from the flue gas again, etc.
  • the water is therefore preferably circulated in a circle for this purpose.
  • Warm water (>44-90°C) or heated cooling water are preferably not used to evaporate the NH3, but only to preheat it to the boiling point. With preheating, a minimally higher temperature of the heat transfer medium of only 10 K relative can still lead to an economical design of a heat exchanger. In contrast, with evaporation, the heat transfer medium should be at least 40 K hotter relative at its coldest point.
  • the warm water or the heated cooling water would have to have a significantly higher temperature, i.e. heat would have to be extracted from the flue gas and/or product gas at a higher temperature to generate it.
  • the low temperature levels are preferably used to generate heated cooling water, in particular the low temperature levels of the flue gas, and therefore preferably only a preheating of NHs takes place, but not an additional evaporation.
  • an additional heat exchanger is provided in the flow direction of the NH; downstream of the tank and upstream of the NH evaporation device, preferably in the flow direction of the NH; downstream of the preheating device, if present, preferably in the flow direction of the NH; upstream of the preheater, if present, which preferably serves to preheat the NEU and in which NH; absorbs heat from water, which is preferably circulated in a circuit and which has previously absorbed heat from the flue gas.
  • the additional heat exchanger is preferably operatively connected to a further heat exchanger.
  • the further heat exchanger is preferably arranged in the flow direction of the flue gas downstream of the flue gas heat exchanger and serves to heat the water by absorbing heat from the flue gas.
  • the additional heat exchanger and the further heat exchanger are preferably connected to one another via a ring line through which the water is circulated, preferably with a pump.
  • the temperature of this water or heated water is therefore preferably significantly below the temperature of the water or water vapor which is used in the NH 3 vaporization device according to the invention for vaporizing NH 3 .
  • the temperature of the heated water i.e. after absorption of heat from the flue gas
  • the temperature of the heated water is preferably at most 110°C, more preferably at most 100°C, even more preferably at most 90°C.
  • the flue gas typically still has a comparatively high temperature of, for example, about 150°C. If the flue gas falls below a temperature of about 120°C, the preheating of the combustion air in a heat exchanger arranged in the flue gas duct by absorbing heat from the flue gas would be no longer satisfactory, as this requires a relatively high temperature difference (see Figures 8 and 9, heat exchanger 43). The residual heat contained in the flue gas cannot therefore be integrated into process streams.
  • the flue gas also contains a high content of N2: A proportion of N2 is released during the combustion of NH3. A proportion of N2 is contained in the combustion air. A proportion of N2 is generated during the catalytic decomposition of NH3 and is optionally returned to the combustion device from a device for purifying H2, preferably a pressure swing absorption device. Due to the high content of N2, the dew point of the flue gas is very low under the prevailing pressure conditions, e.g. at around 60°C. In order to avoid condensation, which could lead to damage to the heat exchangers installed in the flue gas duct, according to the invention a temperature difference of 25°C is preferably maintained as a safety margin from the dew point.
  • this residual heat in the flue gas (temperature range from about 85°C to about 120°C) is used by being absorbed by the water circulating in the circuit.
  • an additional heat exchanger is preferably provided in the flue gas duct, through which water circulates as a heat transfer medium, preferably driven by a pump (see Figure 10).
  • the water is heated in this additional heat exchanger, for example, from about 40°C to about 90°C and can then in turn serve as a heat source for NH3, which has advantageously already been preheated by the cooling water.
  • a power of 101 kW can be absorbed and used to heat NH3 until the boiling point of the NH3 is reached.
  • the preheater arranged downstream in the direction of flow of the NH3 increases the proportion of evaporated NH3 to about 34%.
  • the NEL evaporation device used in the fourth stage then only needs to provide a power of, for example, 320 kW.
  • the amount of heat required to generate the water vapor can be almost halved in this way.
  • the yield in relation to the amount of H2 generated can thus be increased by, for example, about 0.3%.
  • the water vapor preferably has a somewhat higher pressure than the NH3, so that in the event of damage to a heat exchanger (e.g. due to a pipe burst), water vapor would possibly flow into the NH3.
  • a heat exchanger e.g. due to a pipe burst
  • water vapor would possibly flow into the NH3.
  • NFE evaporation devices preferred according to the invention and preheaters preferred according to the invention are equipped independently of one another in such a way that they remove any water (high boilers) contained in the NH3 as a "blowdown", so that in such a case no water breakthrough would possibly occur in the process.
  • At least two heat exchangers are used for the evaporation of NH3, in which NH3 is first preheated to the boiling point and then evaporated.
  • the preheating, heating and evaporation of the NH3 are decoupled from the decomposition of the NH3 and the further process path.
  • the NH 3 is preferably stored as starting material.
  • the stored NH 3 is in liquid form in a cooled tank, at atmospheric pressure and at a temperature below its boiling point of -33.5 °C.
  • NH 3 is fed into the system using a pump, preferably at system pressure.
  • the increased system pressure increases the boiling point of the NH 3.
  • heat must be added to evaporate the NH 3.
  • the evaporation of NH 3 requires considerable amounts of heat.
  • a pressure of 30 bar for example, approximately 2.4 t/h of NH 3 can be preheated and evaporated per megawatt of energy input.
  • the NH3 Before the NH3 can be catalytically decomposed, it is preferably heated successively to several temperature levels according to the invention.
  • a preheater is arranged in the flow direction of the NH3 downstream of the tank and upstream of the NEL evaporation device, which preheater preferably serves to heat the NH3 to the desired temperature at the inlet to the NEE evaporation device and in which NH3 absorbs heat from water, which in turn has previously left the NEE evaporation device as water vapor condensate.
  • water vapor and water vapor condensate are passed in countercurrent through the preheater and the NEE evaporation device (see Figures 4-10, preheater 13).
  • a first heat exchanger is arranged in the flow direction of the NH3 downstream of the NEE evaporation device, which preferably serves to further heat the NH3 and in which NH3 preferentially absorbs heat from product gas (see Figures 8 and 9, heat exchanger 20).
  • a second heat exchanger is arranged in the flow direction of the NH3 downstream of the first heat exchanger, which preferably serves to further heat the NH3 and in which NH3 preferably absorbs heat from flue gas (cf. Figures 8 and 9, heat exchanger 22).
  • an additional heat exchanger is provided in the flow direction of the NH3 downstream of the tank and upstream of the NEfi evaporation device, preferably in the flow direction of the NH3 downstream of the possibly present preheating device, preferably in the flow direction of the NH3 upstream of the possibly present preheater, which preferably serves to preheat the NH3 and in which NH3 absorbs heat from water, which is preferably circulated in a circuit and which has previously absorbed heat from the flue gas (cf. Figure 10, additional heat exchanger 73).
  • liquid NH3 is preferably heated in at least one stage, more preferably in at least two stages, even more preferably in at least three stages, particularly preferably in at least four stages and converted from the liquid phase into the gas phase, ie evaporated.
  • the NH3 preferably reaches a medium temperature level ( ⁇ 300°C).
  • the liquid NH3 is preferably heated in a single stage and also evaporated immediately (see Figures 1 to 3).
  • at least one heat exchanger is provided and connected for this purpose (see Figure 1, flue gas heat exchanger 52; Figure 2, product gas heat exchanger 26).
  • at least two heat exchangers are provided and connected for this purpose (see Figure 3, product gas heat exchanger 26 and flue gas heat exchanger 52).
  • the NH3 is preferably first heated in a first stage (but not yet completely evaporated) and then evaporated in a second stage (see Figures 4 to 6, 8, 9).
  • at least one heat exchanger is provided and connected for the first stage and at least one heat exchanger is also provided and connected for the second stage (see Figure 4, stage 1: preheater 13; stage 2: product gas heat exchanger 26 or flue gas heat exchanger 52).
  • At least one heat exchanger is provided for the first stage and at least two heat exchangers are provided for the second stage (see Figures 5, 6, 8 and 9 stage 1: preheater 13; stage 2: product gas heat exchanger 26 and flue gas heat exchanger 52).
  • the liquid NH3 is preferably first preheated in a first stage (but not yet completely evaporated), then additionally heated in a second stage (but also not yet completely evaporated) and then evaporated in a third stage (see Figure 7).
  • the ratio of condensation enthalpy and latent heat of the water vapor condensate is such that the preheater already evaporates a certain part of the NH3 even in two-stage operation. If one wanted to use the preheater exclusively for preheating in order to realize the evaporation of NH3 exclusively via the condensation enthalpy of the water vapor, the amount of water vapor would have to be increased considerably and the water vapor condensate would emerge with a very high remaining temperature, which would be a disadvantage.
  • At least one heat exchanger is provided and connected for the first stage, at least one heat exchanger for the second stage and at least one heat exchanger for the third stage (see Figure 7, stage 1: preheating device 70; stage 2: preheater 13; stage 3: product gas heat exchanger 26 or flue gas heat exchanger 52).
  • At least one heat exchanger is provided for the first stage, at least one heat exchanger for the second stage and at least two heat exchangers for the third stage (not shown as a figure; corresponds to variation of Figure 5 or 6 by the embodiment according to Figure 7; stage 1: Preheating device 70; stage 2: preheater 13; stage 3: product gas heat exchanger 26 and flue gas heat exchanger 52). From Figure 10, a three-stage heating and evaporation of the liquid NH; can also be derived, namely if either preheating device 70 is missing or if the additional heat exchanger 73 is missing.
  • the liquid NH is preferably first preheated in a first stage (but not yet evaporated), then additionally heated in a second stage (but also not yet completely evaporated), then additionally heated in a third stage (but also not yet completely evaporated) and finally evaporated in a fourth stage (see Figure 10).
  • At least one heat exchanger is provided and connected for the first stage, at least one heat exchanger for the second stage, at least one heat exchanger for the third stage and at least one, preferably at least two heat exchangers for the fourth stage (see Figure 10, stage 1: preheating device 70; stage 2: additional heat exchanger 73; stage 3: preheater 13; stage 4: product gas heat exchanger 26 (not shown) and flue gas heat exchanger 52).
  • NH 3 is then preferably further heated to a high temperature level (>300°C) by absorbing heat from flue gas and/or product gas.
  • heat is absorbed in at least one heat exchanger from the product gas in the flow direction of the product gas downstream of the NH 3 decomposition device and/or from the flue gas in the flow direction of the flue gas downstream of the combustion device.
  • the further heating of NEU is initially carried out by absorbing heat from the product gas in a first heat exchanger provided and connected for this purpose.
  • the first heat exchanger is preferably arranged in the flow direction of the product gas downstream of the NH s decomposition device and is flowed through on the one hand by the hot product gas and on the other hand by the NEU to be further heated. Heat recovered from the product gas is thus used for further heating of NEU (cf. Figures 8 and 9, heat exchanger 20).
  • the further heating of NEW takes place alternatively or subsequently by absorbing heat from the flue gas in a second heat exchanger provided and connected for this purpose.
  • the second heat exchanger is preferably arranged downstream of the combustion device in the flow direction of the flue gas and is flowed through on the one hand by the hot flue gas and on the other hand by the NEE to be further heated. Heat recovered from the flue gas is thus used to further heat NEW (see Figures 8 and 9, heat exchanger 22).
  • the catalytic decomposition of NH3 according to the invention is the actual reaction for the formation of H2, which basically takes place thermally, but is accelerated by the use of an NHs decomposition catalyst.
  • the catalytic decomposition of NH3 can be carried out according to the invention under various conditions using various NEE decomposition catalysts and with various connections with different reactor types.
  • the catalytic decomposition of NH3 is preferably carried out by supplying heat in the presence of a NEE decomposition catalyst.
  • Important parameters for the catalytic decomposition of NH3 are the type of NHs decomposition catalyst, the reaction temperature and the reaction pressure.
  • NH3 decomposition catalyst various materials can be used as NH3 decomposition catalyst.
  • the reaction temperature at which the catalytic decomposition of NH3 takes place is determined in particular by the choice of the NH3 decomposition catalyst.
  • a nickel-based NHs decomposition catalyst is used.
  • the reaction temperature and the reaction pressure determine the equilibrium conversion. At 900°C and 20 bar pressure, the decomposition of NH3 is almost quantitative. At 650°C, the conversion of NH3 is about 98.5%, at 500°C only about 95%.
  • reaction temperatures are preferably set in the range from about 600°C to about 900°C, preferably about 600°C to about 700°C, so that a high conversion is achieved. With regard to energy balance and conversion, optimal reaction temperatures are in the range from about 630°C to 640°C.
  • Nickel-based NHs decomposition catalysts are advantageous despite the comparatively high reaction temperature.
  • non-decomposed NH3 Due to the high conversion, the remaining content of non-decomposed NH3 in the product gas is comparatively low, so that separate separation of non-decomposed NH3 for its recovery is preferably avoided. Instead, N2 and non-decomposed NH3 are separated together from the product gas by pressure swing adsorption during the purification of H2.
  • the NH3 decomposition catalyst comprises supported nickel.
  • Preferred carrier materials are selected from the group consisting of Al2O3, MgO, SiCE, mesoporous SiCE (e.g. MCF-17, MCM-41, SBA-15), zeolite (e.g.
  • reaction temperatures are preferably in the range from about 450°C to about 500°C, although somewhat lower conversions of, for example, about 95% can be achieved, so that the remaining residual content of non-decomposed NH3 in the product gas is greater.
  • NH3 decomposition catalysts can optionally be used at even lower reaction temperatures. The lower the reaction temperature, the lower the conversion and the more non-decomposed NH3 must be separated from the product gas and recycled.
  • the reaction pressure is preferably about 15 bar a to about 25 bar a.
  • the stoichiometry of the reaction (2 NH3 N2 + 3 H2) increases the volume, which is why an increased reaction pressure generally has a negative effect on the conversion.
  • a reaction pressure of only 1 bar conversions of more than 99% could be achieved at reaction temperatures from 400°C.
  • the system according to the invention is preferably operated at a higher reaction pressure, even if this means that a certain loss in conversion has to be accepted.
  • the reaction pressure is particularly predetermined by the way in which the purification of H2 is carried out.
  • the pressure swing absorption (PSA) preferred according to the invention for purifying H2 can preferably be operated effectively at a pressure in the range from about 15 bar to about 25 bar.
  • the pressure of the product gas when leaving the NEE decomposition device is preferably in the range from about 15 to about 25 bar a, more preferably about 18 bar a to about 22 bar a, even more preferably about 19 bar a to about 21 bar a. In this way, a good balance is found between the requirements of pressure swing adsorption on the one hand and the conversion achieved on the other.
  • the decomposition of NH3 can basically take place in different reactor types.
  • adiabatic reaction the internal heat of the reaction gas is used as an energy source for the reaction.
  • Suitable reactors for this are autothermal reformers and secondary reformers, which operate with internal energy generation. Combustion air is added to the process gas and part of the reaction gas is burned in order to increase the temperature so that the desired temperature prevails at the reactor outlet.
  • a disadvantage is the presence of water in the process gas produced during combustion, which must be removed by condensation. Part of the non-decomposed NH3 then dissolves in the condensed water and is lost. In addition, the high temperatures lead to the formation of considerable amounts of nitrogen oxides.
  • the product gas is formed in the NEE decomposition device according to the invention by decomposition of NH3 and leaves the NHs decomposition device via its own outlet.
  • the combustion gas is burned together with combustion air in the combustion device and the flue gas formed in the process also leaves the combustion device via its own outlet, preferably into a flue gas duct.
  • Product gas and flue gas are not mixed with one another, but remain physically separated from one another. Combustion heat formed during the combustion of the combustion gas flows as a heat flow into the NHs decomposition device and thus supplies the heat required to maintain the endothermic decomposition of NH3.
  • the catalytic decomposition of NH3 is preferably carried out isothermally, quasi-isothermally or in a mixed form of isothermal and adiabatic process control.
  • isothermal reaction control the temperature of the gas remains largely unchanged.
  • the catalytic decomposition of NH3 takes place in a reactor analogous to a primary reformer.
  • the reactor comprises both the NEfi decomposition device according to the invention and the combustion device according to the invention.
  • the NH3 decomposition catalyst is preferably arranged in at least one tube through which NH3 flows, more preferably at least two tubes, even more preferably at least three tubes (NEE decomposition device).
  • the at least one tube contains the NPh decomposition catalyst.
  • the at least one tube is preferably flowed through with NH3 from top to bottom.
  • a mixture of NH3 and H2 is preferably burned together with combustion air as combustion gas (combustion device).
  • the N2 formed alongside H2 during the catalytic decomposition of NH3 is inert and serves as an additional heat carrier.
  • the combustion heat generated by the combustion process in the combustion chamber of the combustion device is used to heat the NEfi decomposition device, preferably the tube or tubes through which the NH3 to be decomposed is passed.
  • a heat flow is directed from the combustion device into the NPh reduction device.
  • NH3 is preheated before entering the NEfi decomposition device according to the invention. Due to this preheating, the temperature of the NH3 before entering the NEfi decomposition device according to the invention is preferably at least about 600°C, preferably at least about 630°C. The temperature of the NH3 is preferably at most about 850°C, more preferably at most about 820°C. The temperature of the NH3 when entering the NEfi decomposition device according to the invention is particularly preferably about 780°C to 820°C, preferably about 800°C.
  • the NEfi decomposition device according to the invention and the combustion device according to the invention preferably form a reactor designed analogously to a primary reformer.
  • the NH3 decomposition catalyst is preferably nickel-based.
  • the reaction temperature in the NEfi decomposition device, preferably in the at least one tube which contains the NEfi decomposition catalyst and through which the NH3 is passed is preferably about 630°C to about 670°C, preferably about 650°C. In other preferred embodiments, this temperature is about 660°C to 700°C, preferably about 680°C.
  • the product gas leaves the reactor (the NH s decomposition device) preferably at a pressure of about 15 bar a to about 25 bar a, preferably about 20 bar a.
  • the decomposition of NH takes place in two stages in two NEE decomposition devices through which the gas flows one after the other (see Figure 9).
  • a pre-reactor first NHs decomposition device
  • only a portion of the NH is initially decomposed.
  • the remaining decomposition of NH; up to the maximum conversion achieved then takes place in a second NHs decomposition device.
  • the second NEE decomposition device preferably forms, together with the combustion device according to the invention, a reactor as described in more detail above and designed analogously to a primary reformer.
  • the NH is preheated before being introduced into the pre-reactor (first NEE decomposition device).
  • the temperature of the NEU after heating and upon entry into the pre-reactor (first NEE decomposition device) is about 620°C to about 680°C, more preferably about 650°C.
  • the preheated NEU then enters the pre-reactor, which contains NEE decomposition catalyst and in which a catalytic decomposition of NEE to N2 and EE takes place to a certain extent.
  • An intermediate product gas is formed which still contains considerable residual amounts of undecomposed NEE, but also N2 and EE which have already been formed. As a result of the endothermic decomposition of NEE, the intermediate product gas cools down preferentially.
  • the conversion of decomposed NEE in the pre-reactor is at most 25%, more preferably at most 20% of the total conversion achieved.
  • the combustion device preferably has one or more burners, preferably at least two burners, more preferably at least three burners.
  • the combustion gas preferably contains NH3.
  • the combustion device according to the invention is therefore preferably an NHs combustion device.
  • the combustion gas preferably contains a mixture of H2 and NH3, since this mixture produces a medium flame temperature and has better combustion properties than pure NH3.
  • a suitable mixing ratio of H2 and NH3 also results in less nitrogen oxide being formed than in the absence of H2.
  • combustion air is supplied to the combustion device (combustion chamber of the reactor), which is preferably preheated beforehand in at least one heat exchanger.
  • this at least one heat exchanger is arranged in the flue gas channel, whereby the combustion air absorbs heat from the flue gas.
  • excess heat in the flue gas can be used to preheat the combustion air (see Figures 8 and 9, heat exchanger 43 or heat exchanger 45).
  • the combustion air is preheated in at least two heat exchangers.
  • these at least two heat exchangers are both arranged in the flue gas channel, wherein the combustion air each absorbs heat from the flue gas.
  • a first heat exchanger is arranged in the flue gas channel in the flow direction of the flue gas downstream of the flue gas heat exchanger and preferably serves to preheat the combustion air, wherein the combustion air absorbs heat from the flue gas (see Figures 8 and 9, heat exchanger 43).
  • a second heat exchanger is arranged in the flue gas channel in the flow direction of the flue gas upstream of the flue gas heat exchanger and preferably serves to further heat the combustion air, wherein the combustion air again absorbs heat from the flue gas (see Figures 8 and 9, heat exchanger 45).
  • the combustion air is cleaned by a filter before being fed into the system, compressed to the required pressure using a compressor and then passed through at least one heat exchanger in the flue gas duct and heated. From there, the heated combustion air flows combustion air into the combustion device. Shortly before entering the combustion device or within the combustion device, the combustion air is mixed with the combustion gas (preferably NH3 mixed with H2).
  • the combustion gas preferably NH3 mixed with H2.
  • the product gas leaves the NH s decomposition device at a high temperature.
  • at least one heat exchanger is preferably arranged in the flow direction of the product gas downstream of the NH s decomposition device, through which the product gas flows before the product gas is fed to a purification of H 2.
  • at least two heat exchangers, more preferably at least three heat exchangers, even more preferably at least four heat exchangers are flowed through by the product gas before the product gas is fed to a purification of H 2.
  • the temperature of the product gas at the exit from the NEL decomposition device is in the range of about 650 ⁇ 100°C, more preferably about 650 ⁇ 50°C.
  • a product gas heat exchanger is arranged as part of an H2O evaporation device downstream of the NH3 decomposition device in the flow direction of the product gas.
  • the product gas heat exchanger is preferably operatively connected to a steam drum.
  • the H2O evaporation device thus preferably comprises the product gas heat exchanger and the steam drum.
  • Heat contained in the hot product gas leaving the NH3 decomposition device is preferably absorbed by water in the product gas heat exchanger and used to heat or generate steam in the steam drum.
  • the steam drum is preferably fed with demineralized water.
  • the steam is fed via a pipe system into the NH3 evaporation device, in which NH3 absorbs heat from the steam and evaporates. After leaving the NEE evaporation device, the NH3 is then further heated and fed to the NEL decomposition device.
  • a further heat exchanger is arranged in the flow direction of the product gas downstream of the product gas heat exchanger (H2O evaporation device), which preferably serves to heat the NH3 to the desired temperature at the inlet to the NEL decomposition device or to an intermediate temperature even lower than that.
  • H2O evaporation device the product gas heat exchanger
  • the temperature of the product gas at the outlet from the preheater is in the range of about 90 ⁇ 50°C, more preferably about 90 ⁇ 25°C.
  • an additional heat exchanger is arranged in the flow direction of the product gas, preferably in the flow direction of the product gas downstream of the preheater for water, which preferably serves to heat water and brings the product gas to the desired temperature for a preferably subsequent purification of H 2 (cf. Figures 8 and 9, process cooler 29).
  • the heat absorbed by the water in this process is preferably used according to the invention to preheat liquid NH3.
  • the temperature of the product gas at the outlet from the additional heat exchanger is in the range of about 35 ⁇ 15°C, more preferably about 35 ⁇ 10°C.
  • the recovery of NH3 preferred according to the invention preferably serves to separate non-decomposed NH3 from the product gas and to make it available for further use as combustion gas or recovered reactant.
  • NH3 can be separated technically in various ways, e.g. membrane separation, adsorption and condensation, but these processes require high pressures and are therefore energy-intensive.
  • the absorption of NH3 in water can be carried out at process pressures.
  • water vapor is required as an energy carrier.
  • the combustion gas also comprises NH3, preferably in a mixture with H 2 , additional NH3 or H 2 must be burned to generate the water vapor required for the rectification, which leads to a reduction in the overall yield of H 2 .
  • the reaction parameters are selected so that the highest possible conversion is achieved and thus the amount of undecomposed NH3 in the product gas is kept as low as possible. However, this is hardly possible with a high reaction temperature alone in an economical process, since the equilibrium temperature would then have to be 900°C or even higher.
  • the purification of H2 from the product gas is preferably carried out by pressure swing adsorption (PSA).
  • PSA pressure swing adsorption
  • small residual amounts of undecomposed NH3 can preferably be separated during pressure swing adsorption, whereby the recovery of NH3 and the purification of H2 are combined into a common step.
  • H2 The type of purification of H2 in the product gas depends on the subsequent technical use of the H2, which determines the quality requirements.
  • Technical H2 can remain relatively impure and, for example, have a purity of about 99.7%. If, however, H2 is intended for use in fuel cells, a significantly higher purity in the range of, for example, about 99.96% would be necessary.
  • H2 is purified by partial condensation, for example, analogously to air separation.
  • this requires the use of a compressor to generate the high required inlet pressures of, for example, about 230 bar.
  • upstream adsorptive drying is necessary to remove traces of NH3 and H2O.
  • the separation unit itself is required, which is why this concept is cost-intensive in terms of investment and operation.
  • H2 is purified by membranes.
  • H2 and N2 can be separated from one another with only moderate selectivities and yields. Even for separation via membranes, a high inlet pressure must be created, which requires the use of a compressor.
  • H2 is particularly preferably purified by pressure swing adsorption (PSA).
  • PSA pressure swing adsorption
  • An adsorptive separation in a pressure swing adsorption device is preferred according to the invention, among other things because it takes place at moderate pressures and additionally also achieves high purity of H2, if required > 99.9%, with a yield of H2 of eg approx. 85%.
  • the Pressure swing adsorption also removes residual amounts of NH3 and H2O in the same step.
  • the product gas is preferably cooled to the desired temperature using a process cooler before entering the pressure swing adsorption device.
  • the corresponding amount of heat is preferably absorbed by water in the process cooler (see Figures 8 and 9, process cooler 29).
  • the cooling water heated in this way is preferably used according to the invention to preheat NH3 in a preheating device in which NH3 absorbs heat from the water (see Figure 7, preheating device 70).
  • the cooled product gas is then preferably fed to a pressure swing adsorption device, where the gas mixture is separated under pressure by adsorption.
  • the H2 separated in this way preferably leaves the device for purifying H2, preferably the pressure swing adsorption device, and is preferably brought to an increased pressure using an F-compressor.
  • the compressed H2 then preferably flows through a heat exchanger in which cooling water absorbs heat from the compressed H2 (see Figures 8 and 9, compressor 33 and heat exchanger 34).
  • the separated H2 is then brought to a further increased pressure using a second compressor.
  • the further compressed H2 then flows through a second heat exchanger in which cooling water also absorbs heat from the compressed H2 (see Figures 8 and 9, compressor 35 and heat exchanger 36).
  • the cooling water heated in this way is preferably used for preheating NH3 in a preheating device in which NH3 absorbs heat from the water (cf. Figure 7, preheating device 70).
  • the compressed H2 is then discharged from the plant at a pressure of, for example, about 70 bar and, for example, stored in a suitable pressure vessel or directly fed for further use.
  • the residual gas mixture is fed to the combustion device so that it can be used to generate combustion heat.
  • the flue gas leaves the combustion device at a high temperature and preferably enters a flue gas channel.
  • at least one heat exchanger is preferably arranged downstream of the combustion device in the flow direction of the flue gas, through which the flue gas flows before the flue gas is released to the environment, e.g. via a chimney.
  • the flue gas flows through at least two heat exchangers, more preferably at least three heat exchangers, even more preferably at least four heat exchangers, before the flue gas is released to the environment.
  • the temperature of the flue gas exiting the combustion device is in the range of about 850 ⁇ 100°C, more preferably about 850 ⁇ 50°C.
  • the temperature of the flue gas exiting the combustion device is in the range of about 880 ⁇ 100°C, more preferably about 880 ⁇ 50°C.
  • a first heat exchanger is arranged in the flue gas channel in the flow direction of the flue gas downstream of the combustion device, which first heat exchanger preferably serves to heat the NH; to the desired temperature at the inlet to the NHs decomposition device.
  • the temperature of the flue gas at the outlet from the first heat exchanger is in the range of about 700 ⁇ 100°C, more preferably about 700 ⁇ 50°C.
  • a second heat exchanger is arranged downstream of the first heat exchanger in the flow direction of the flue gas, which second heat exchanger preferably serves to heat the combustion air.
  • the temperature of the flue gas at the outlet from the second heat exchanger is in the range of about 300 ⁇ 100°C, more preferably about 300 ⁇ 50°C.
  • the temperature of the flue gas at the outlet from the flue gas heat exchanger is in the range of about 250 ⁇ 100°C, more preferably about 250 ⁇ 50°C.
  • an additional heat exchanger is arranged in the flow direction of the flue gas, preferably in the flow direction of the flue gas downstream of the flue gas heat exchanger, which preferably serves to heat combustion air (cf. Figures 8 and 9, heat exchanger 43).
  • a further heat exchanger is preferably arranged in the flow direction of the flue gas downstream of the first heat exchanger and preferably in the flow direction of the flue gas upstream of the second heat exchanger, which preferably serves to heat the intermediate product gas after leaving the first NH 3 decomposition device (pre-reactor) and before entering the second NH 3 decomposition device (together with combustion device analogous to primary reformer) (cf. Figure 9, further heat exchanger 67).
  • the temperature of the flue gas at the outlet from the further heat exchanger is in the range of about 450 ⁇ 100°C, more preferably about 450 ⁇ 50°C.
  • the flue gas leaving the combustion device represents the largest energy sink of the process after the catalytic decomposition of the NH; and the evaporation of the NH;.
  • the energy recovery from the flue gas is limited by the fact that temperature differences of less than approximately 45 K between the flue gas and the other process-side streams (reactant for the catalytic decomposition, combustion gas, combustion air, water for the generation of water vapor) would require uneconomically large heat exchangers. Therefore, even after all economically viable steps of the process-side heat integration, a certain temperature difference remains between the flue gas and the dew point of the water contained in the flue gas.
  • this remaining temperature difference is preferably used to generate heated cooling water, which is then used to preheat NH3.
  • Demineralized water is preferably fed into the plant as water for the production of steam.
  • the water is preheated via a preheater, through which product gas preferably flows and in which the water absorbs heat from the product gas (see Figures 8 and 9, preheater 28).
  • the preheater is preferably arranged downstream of the product gas heat exchanger.
  • the water after leaving the preheater has a temperature of at least 100°C, more preferably at least 110°C, even more preferably at least 115°C.
  • the temperature of the water subsequently no longer falls below this temperature of at least 100°C, more preferably at least 110°C, even more preferably at least 120°C, before the water in the NEL evaporation device according to the invention releases heat to NH3 for its evaporation.
  • air and other gases dissolved in the water are removed in a degasser.
  • the water is then passed through the flue gas heat exchanger and heated.
  • the flue gas heat exchanger cools the flue gases from the combustion device in the flue gas channel, whereby the heat contained in the flue gas is used to heat the water vapor.
  • the water after leaving the flue gas heat exchanger has a temperature of at least 180°C, more preferably at least 200°C, even more preferably at least 220°C.
  • the temperature of the water subsequently does not fall below this temperature of at least 180°C, more preferably at least 200°C, even more preferably at least 220°C, before the Water in the NHs evaporation device according to the invention transfers heat to NH3 for its evaporation.
  • the water may be in liquid, gaseous (i.e. as water vapor) or as a two-phase system.
  • the steam is then preferably fed into a steam drum (see Figures 1-9, steam drum 60).
  • the water is preferably passed through the product gas heat exchanger and thereby absorbs further heat in order to then preferably be returned to the steam drum.
  • the product gas heat exchanger is arranged downstream of the NH s decomposition device in the flow direction of the product gas and serves to cool the product gas after it leaves the NH s decomposition device, wherein heat contained in the product gas is also used to heat the steam.
  • the hot steam preferably leaves the steam drum and is preferably introduced into the NH3 evaporation device. Heat is gained through the condensation of the steam in order to evaporate the preheated NH3.
  • the steam condensate is preferably fed to the preheater, which serves to preheat the NH3 so that the heat contained in the steam is used in two stages to heat the NH3. After flowing through the preheater, the steam condensate can be discharged from the system.
  • the process provides heat, it is preferred to recover this heat by producing more than the required amount of boiler feed water and separating this amount before entering the FEO evaporator and mixing it with the blowdown.
  • the steam leaving the flue gas heat exchanger is preferably divided into two partial streams.
  • a first partial stream is preferably introduced into the steam drum.
  • a second partial stream preferably bypasses the steam drum via a bypass and is mixed with the blowdown ( Figure 6).
  • Such a preferred water stream according to the invention comprises cooling water, which preferably comes from a process cooler in the flow direction of the product gas upstream of a device for Purification of H2, preferably a pressure swing adsorption device, where it has previously absorbed heat from the product gas (heated cooling water), or from a heat exchanger of a possible FL compressor, where it has previously absorbed heat from compressed H2 (heated cooling water).
  • a device for Purification of H2 preferably a pressure swing adsorption device, where it has previously absorbed heat from the product gas (heated cooling water), or from a heat exchanger of a possible FL compressor, where it has previously absorbed heat from compressed H2 (heated cooling water).
  • Another such water stream preferred according to the invention comprises water which is preferably circulated in a circuit and which has previously absorbed heat from the flue gas, for which purpose an additional heat exchanger is preferably in operative connection with a further heat exchanger, wherein these are preferably connected to one another via a ring line through which the water is circulated, preferably with a pump.
  • Figures 1 to 16 each show, using flow diagrams, preferred embodiments of systems according to the invention on which preferred embodiments of the method according to the invention can be carried out.
  • Figures 4, 7, 10 and 12-16 each show only a part of embodiments according to the invention, which are preferred as preferred developments of all other figures of embodiments according to the invention.
  • a first exemplary flow diagram of a system according to the invention is explained below with reference to Figure 1.
  • Liquid NH3 is fed from tank 10 into NFL evaporation device 14 and evaporated therein.
  • the heat required for this is obtained by condensing water vapor (see below).
  • the evaporated NH3 flows into NFL combustion device 24, where the endothermic decomposition of NH3 to N2 and H2 is catalyzed.
  • the heat required to maintain the reaction is generated as combustion heat by burning combustion gas (e.g. NFL/FL/air or CH air) and introduced as a heat flow from the combustion device 18 into the NFL combustion device 24.
  • combustion gas e.g. NFL/FL/air or CH air
  • the flue gas obtained during combustion flows through flue gas heat exchanger 52, whereby heat contained in the flue gas is transferred to water, thereby producing water vapor.
  • the water vapor After passing through flue gas heat exchanger 52, the water vapor is introduced into water vapor drum 60 and then via line 63 into NFL evaporation device 14.
  • the NFL is evaporated by the heat released during the condensation of the water vapor in NFL evaporation device 14 (see above).
  • Figure 2 illustrates a variant according to the invention of the embodiment according to Figure 1, the essential difference being that it is not the heat in the flue gas but the heat in the product gas that is used to heat water and to heat water vapor.
  • the product gas obtained during the catalytic decomposition flows through product gas heat exchanger 26, whereby heat contained in the product gas is released to water, thereby obtaining water vapor.
  • the steam is introduced into the steam drum 60 and then via line 63 into the NH3 evaporator 14.
  • Figure 3 illustrates a variant according to the invention in which both flue gas heat exchanger 52 and product gas heat exchanger 26 are used to heat water or water vapor.
  • Water vapor is passed from flue gas heat exchanger 52 and from product gas heat exchanger 26 into water vapor drum 60. From there, the water vapor is then introduced into NH 3 evaporation device 14 via line 63.
  • FIG. 4 illustrates a detail of a variant according to the invention in which liquid NH; from tank 10 is first fed into preheater 13 and preheated therein by absorbing heat from heated water before the preheated NH; is fed to the NHs evaporation device 14.
  • the heated water used is fed as steam condensate via line 64 from the NHs evaporation device 14 to the preheater 13.
  • the heat contained in the steam is used in two stages for the heating and subsequent evaporation of NH;.
  • the steam condensate can be discharged from the system, for example.
  • Figure 5 illustrates a variant according to the invention which takes into account that when steam is generated at boiling temperature, a liquid stream is also produced as a "blowdown".
  • the "blowdown” is added to the condensed steam after it leaves the NH 3 evaporation device 14 and before it enters the preheater 13.
  • the "blowdown” is fed via "blowdown" line 68 from the steam drum 60 into line 64.
  • FIG. 7 illustrates a detail of a variant according to the invention in which the yield of H2 is increased by reducing the amount of water vapor generated and instead reintegrating residual heat remaining in the process. This ultimately requires less fuel, which preferably contains H2.
  • the energy gap in the preheating and evaporation of NH3 is closed by a preheating device 70 fed with cooling water.
  • Water for cooling may be required at various points in the system, for example in process cooler 29 in the flow direction of the product gas upstream of a device for purifying H2, preferably a pressure swing adsorption device 31, or in Heat exchangers 34 or 36, possible H2 compressors 33 or 35.
  • the water absorbs process heat and is thereby heated.
  • the absorbed heat can be used to preheat liquid NH.
  • a second partial flow of the NH3, starting from branch 16, is led via line 19 through heat exchanger 20 and then flows via line 21 through heat exchanger 22, where the NH3 is further heated and then flows via line 23 into NH; decomposition device 24, where the NH 3 decomposition catalyst is located, so that the catalytic decomposition of NH; takes place there.
  • the NFL decomposition device 24 is preferably flowed through from top to bottom. The heat required to maintain the reaction is generated by heating the NFL decomposition device 24 by combustion of NH; in the combustion device 18.
  • the FL separated in this way leaves the device for purifying FL, preferably the pressure swing adsorption device, 31 via line 32, is brought to an increased pressure via a first FL compressor 33, flows through a heat exchanger 34, a second FL compressor 35 for further pressure increase, a second heat exchanger 36 and is discharged from the system at a pressure of, for example, about 70 bar via line 37.
  • Water for the production of steam is fed in via line 55, passed through preheater 28 and then passed at an increased temperature into degasser 56, in which air and other gases dissolved in the water are removed.
  • the water is passed through flue gas heat exchanger 52 via line 58 and heated.
  • Flue gas heat exchanger 52 serves to cool the flue gases from combustion device 18 in flue gas channel 49, whereby the thermal energy contained in the flue gas is used to heat the steam, which is then passed via line 59 into steam drum 60 after passing through flue gas heat exchanger 52.
  • Water can be passed from steam drum 60 via line 61 through product gas heat exchanger 26 and thereby absorb further thermal energy, in order to then be returned to the steam drum via line 62.
  • the product gas heat exchanger 26 is arranged in the outlet line 25 in the flow direction of the product gas downstream of the NH s decomposition device 24 and serves to cool the product gas after leaving the NH s decomposition device 24.
  • the heat obtained can thus be used to generate further water vapor.
  • the hot steam generated in the steam drum 60 is introduced via line 63 into the upper area of the NH3 evaporation device 14.
  • the condensation of the steam generates the heat to evaporate the preheated NFL.
  • the steam condensate is fed via line 64 to the preheater 13, which serves to preheat the NFL, so that the heat contained in the steam is used in two stages to heat the NFL.
  • the steam condensate can be discharged from the system.
  • Figure 9 also illustrates another variant according to the invention, which is more complex and in which several other systems are integrated. Some parts of the system correspond to those in Figure 8 and are therefore not explained in detail again. Heating and evaporation of the NFL are largely unchanged, as are the parts of the system and process steps downstream of the Device for purifying H2, preferably by pressure swing adsorption, after separating the H2.
  • a total of five heat exchangers are arranged in the flue gas channel 49.
  • line 21 for heating the NH3 leads from heat exchanger 20 to heat exchanger 22 arranged in the flue gas channel 49.
  • the NH3 is passed through pre-reactor 65, where the NH3 cools down.
  • the gas mixture leaving pre-reactor 65 is then led via line 66 to heat exchanger 67, which is arranged in the flue gas channel 49 upstream of heat exchanger 22 in the flow direction of the flue gas.
  • the gas mixture is heated up and then introduced via line 23 into NfL reduction device 24.
  • the combustion air for the combustion device 18 is heated as shown in Figure 8, first by heating via heat exchanger 43 and then by further heating via heat exchanger 45, with both heat exchangers 43 and 45 being arranged in the flue gas duct 49.
  • the heating and evaporation of the water supplied to the steam drum 60 is carried out via preheater 28 and flue gas heat exchanger 52, which is arranged in the flue gas duct 49, as shown in Figure 8.
  • five heat exchangers 67, 22, 45, 52 and 43 are arranged one behind the other in the flow direction of the flue gas in the flue gas duct 49.
  • a difference in the reaction procedure according to Figure 9 compared to Figure 8 is that the preheating of the NH3 is limited to lower temperatures, which extends the service life of the steel from which the Nkh decomposition device 24 is made, even in contact with NH3.
  • the incoming gas stream is first preheated and then part of the catalytic decomposition is carried out in the pre-reactor 65.
  • the gas mixture leaving the pre-reactor 65 is then heated again and passed into the Nkh decomposition device 24, where the remaining catalytic decomposition takes place.
  • FIG 10 illustrates a detail of a variant according to the invention in which a further heat flow from the system is integrated into the preheating of NH3.
  • this heat in the flue gas is used by being absorbed by another water as a heat transfer medium.
  • a further heat exchanger 71 is mounted in the flue gas channel 49, through which water circulates as a heat transfer medium, driven by pump 72. The water is heated in the further heat exchanger 71 and can then in turn serve as a heat source for NH3 in an additional heat exchanger 73, which was advantageously previously preheated by the cooling water in the preheating device 70 fed by the cooling water.
  • FIG 11 schematically illustrates possible sources for heated cooling water 80a to 80d, which is used for preheating and possibly evaporating NH3.
  • only one of these sources for heated cooling water 80a to 80d or several or all of these sources for heated cooling water 80a to 80d can be used to preheat and optionally evaporate NH; (embodiments (a) to (d) and any combinations thereof).
  • Liquid NH enters preheater 13 and absorbs heat from water vapor condensate 76.
  • the NH preheated in this way then enters the NFE evaporation device 14 and absorbs heat from the water vapor 75, which in turn condenses to water vapor condensate 76.
  • a water vapor condensate heat exchanger 83 is arranged downstream of the preheater 13, in which cooling water 80a absorbs heat from the water vapor condensate 76.
  • the evaporated NH leaves the NH s evaporation device 14 and is divided into two partial flows.
  • the combustion device 18 and the NH s decomposition device 24 are in heat exchange with each other.
  • a first partial flow of the evaporated NH s is burned as combustion gas in the combustion device 18 and leaves it as flue gas 78, from which heat is subsequently recovered in a flue gas heat integration 81 and reintegrated into the process, (b) In the flow direction of the flue gas, downstream of the flue gas heat integration
  • a flue gas heat exchanger 52 is arranged, in which cooling water 80b absorbs heat from the flue gas 78.
  • a second partial flow of the vaporized NH is decomposed in the NHs decomposition device 24 into product gas 79.
  • this second partial flow of the vaporized NH is first heated in a product gas heat integration 82 and then in the flue gas heat integration 81.
  • the hot NH then enters the NHs decomposition device 24.
  • heat is recovered from the product gas 79 in the product gas heat integration 82 and reintegrated into the process.
  • Figures 12 to 16 are related to each other and also to Figures 4 to 7, which each relate to the preheating of NH3 in preheater 13 and the subsequent evaporation of NH3 in NFE evaporation device 14.
  • Figures 12 to 16 each illustrate sections of variants according to the invention. In all of these variants, blowdown and boiler feed water (both not shown) are preferably combined with the steam condensate after the steam condensate has left the NFE evaporation device and before it has been returned to the preheater 13.
  • Figure 12 illustrates a comparatively simple variant in which liquid NH3 from tank 10 is first fed into preheater 13 and preheated therein by absorbing heat from heated water before the preheated NH3 is fed to the NHs evaporation device 14.
  • the heated water used is fed as water vapor condensate via line 64 from the NHs evaporation device 14 to the preheater 13.
  • the heat contained in the water vapor is used in two stages for the heating and subsequent evaporation of NH3.
  • the water vapor condensate can be discharged from the system, for example.
  • Figure 13 illustrates a further development of the variant according to Figure 12, wherein a preheating device 70 is arranged in the flow direction of the NH3 downstream of the compressor 12 and upstream of the preheater 13.
  • NH3 is preheated by absorbing heat from heated water before the preheated NH3 is fed to the preheater 13.
  • the heated water can come from different sources, preferably from one of the sources for heated cooling water 80a to 80d explained above in connection with Figure 11, i.e. preferably (a) from a steam condensate heat exchanger 83, (b) from a flue gas heat exchanger 52, (c) from a process cooler 29, or (d) from a heat exchanger 34 and/or 36.
  • Figure 14 illustrates another development of the variant according to Figure 12, wherein an additional heat exchanger 73 is arranged in the flow direction of the NH3 downstream of the compressor 12 and upstream of the preheater 13, which in turn is preferably in operative connection with a further heat exchanger 71 in the flue gas duct.
  • additional heat exchanger 73 NH3 is preheated by absorbing heat from heated water before the preheated NH3 is fed to the preheater 13.
  • the heated water preferably comes from the further heat exchanger 71, in which water absorbs heat from the flue gas in the flue gas duct.
  • a water vapor condensate heat exchanger 83 is arranged in the flow direction of the water vapor condensate downstream of the preheater 13, in which cooling water absorbs heat from the water vapor condensate.
  • Figure 16 illustrates a combination of all variants according to Figures 12 to 15.

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Abstract

L'invention concerne un système et une méthode de préparation de H2 par décomposition catalytique de NH3. De l'eau est utilisée en tant que milieu de transfert de chaleur pour récupérer la chaleur de traitement. La chaleur de traitement est reçue par de l'eau ou de la vapeur d'eau et est ensuite évacuée vers NH3, ce qui permet de chauffer et d'évaporer le NH3. L'utilisation d'eau ou de vapeur d'eau en tant que milieu de transfert de chaleur offre des avantages entre autres en ce qui concerne l'économie et la sécurité.
PCT/EP2024/065287 2023-06-06 2024-06-04 Décomposition catalytique d'ammoniac avec de la vapeur d'eau en tant que milieu de transfert de chaleur Pending WO2024251713A1 (fr)

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KR1020257043793A KR20260018105A (ko) 2023-06-06 2024-06-04 열 전달 매체로서 수증기에 의한 암모니아의 촉매 분해
CN202480050031.XA CN121693462A (zh) 2023-06-06 2024-06-04 以水蒸汽作为传热介质的氨催化分解

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DE102023114883.4A DE102023114883A1 (de) 2023-06-06 2023-06-06 Katalytische Zersetzung von Ammoniak mit Wasserdampf als Wärmeträgermedium
LULU103144 2023-06-06
DE102023114883.4 2023-06-06
LU103144A LU103144B1 (de) 2023-06-06 2023-06-06 Katalytische Zersetzung von Ammoniak mit Wasserdampf als Wärmeträgermedium

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