Classifications

• • 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
  • B01D53/002—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 condensation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
  • B01D2257/504—Carbon dioxide
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present invention relates to a method for capturing carbon dioxide in a fluid comprising at least one more volatile compound than carbon dioxide CO2, for example oxygen O 2, argon Ar, nitrogen N 2, carbon monoxide CO, helium He and / or hydrogen H2.
• the invention can be applied in particular to electricity production units and / or steam from carbonaceous fuels such as coal, hydrocarbons (natural gas, fuel, petroleum residues ...), household waste, biomass, but also to gas from refineries, chemical factories, steel factories or cement factories. It could also apply to the fumes of boilers used for heating buildings or even the exhaust of transport vehicles, more generally to any industrial process generating fumes including CO2.
• carbonaceous fuels such as coal, hydrocarbons (natural gas, fuel, petroleum residues ...), household waste, biomass, but also to gas from refineries, chemical factories, steel factories or cement factories. It could also apply to the fumes of boilers used for heating buildings or even the exhaust of transport vehicles, more generally to any industrial process generating fumes including CO2.
• Carbon dioxide is a greenhouse gas.
• An object of the present invention is to provide an improved method of capturing carbon dioxide from a fluid comprising CO2 and at least one more volatile compound than this.
• the invention firstly relates to a process for producing at least one CO2-poor gas and one or more CO2-rich fluids from a fluid to be treated comprising CO2 and at least one more volatile compound than the CO2, said method implementing: a) cooling in at least one chamber of at least a portion of said fluid to be treated so as to obtain at least one solid comprising predominantly CO2 by cryo-condensation of a portion of the fluid to treating and at least one residual gas constituting said CO2-poor gas; b) an extraction of said enclosure from at least a portion of said solid formed in step a); and c) liquefaction and / or sublimation of at least a portion of said solid extracted in step b) so as to obtain one or more fluids rich in CO2; characterized in that the time intervals during which said step b) is implemented are included in the time intervals during which said step a) is implemented.
• the fluid to be treated generally comes from a boiler or any installation producing smoke. These fumes may have undergone several pre-treatments, in particular to remove NOx (nitrogen oxides), dust, SOx (sulfur oxides) and / or water.
• NOx nitrogen oxides
• SOx sulfur oxides
• the fluid to be treated is either monophasic, in gaseous or liquid form, or multiphase.
• gaseous form is meant “essentially gaseous”, that is to say it may contain especially dust, solid particles such as soot and / or droplets of liquid.
• the mixture to be treated contains CO2 which it is desired to separate by cryo- condensation from the other constituents of said fluid.
• These other constituents comprise at least one or more compounds that are more volatile than carbon dioxide in the sense of condensation, for example oxygen O 2, argon Ar, nitrogen
• the fluids to be treated generally comprise mainly nitrogen, or mainly CO or predominantly hydrogen.
• step a) the fluid to be treated is cooled in at least one chamber.
• This cooling can advantageously be done at least partly by heat exchange with fluids rich in CO2 from the separation process. Complementarily or alternatively, it can be done at least partly by heat exchange with the CO2-poor gas from the separation process. These cold fluids from the separation are heated, while the fluid to be treated is cooled. This reduces the amount of energy required for the cooling operation.
• CO2-poor gas that is to say comprising less than 50% of CO2 by volume and preferably less than 10% CO2 by volume.
• said CO2-poor gas comprises more than 1% of CO2 by volume.
• it comprises more than 2%.
• it comprises more than 5%.
• a solid is formed comprising predominantly CO2, ie at least 90% by volume brought back to the gaseous state, preferably at least 95% by volume and even more preferably at least 99% of CO2 by volume.
• This solid may comprise other compounds than CO2. There may be mentioned, for example, other compounds which would also have solidified, or else bubbles and / or drops of fluid taken in mass in said solid. This explains why the solid may not be purely constituted of solid CO2. This "solid” may comprise non-solid parts such as fluid inclusions (drops, bubbles, etc.).
• step b) at least part of this solid is extracted from the chamber in which the cryo-condensation takes place.
• This extraction can be done without any particular action, because of the conformation of the enclosure where the cry-condensation takes place, or by the intervention of dedicated means.
• the solid extract is possibly transported to other enclosures.
• time interval during which a certain step E is performed we mean the time between a time t1 where step E begins and a time t2 where it ends, without there being any interruption of step E between t1 and t2.
• a time interval [t1; t2] is said inclusive, or included, in a time interval [t3; t4] if t3 occurs before or at the same time as t1, and t4 occurs after or at the same time as t2.
• step a) is taking place.
• the cooling operations of the fluid to be treated and cryocondensation also take place. This naturally assumes that cryo- condensation and extraction involve different molecules.
• step c) the solid is brought back to conditions of temperature and pressure such that it changes to a fluid, liquid and / or gaseous state. It can therefore occur liquefaction (melting) of at least a portion of said solid.
• This gives rise to one or more primary fluids rich in CO2.
• These fluids are said to be “primary” to distinguish them from process fluids that are called “secondary” fluids.
• rich in CO2 is meant “comprising predominantly CO2" in the sense defined above.
• refrigerating cycles each comprising at least one substantially isentropic expansion of a gas.
• These refrigerating cycles consist of several steps that pass a fluid called "working" by several physical states characterized by given conditions of composition, temperature, pressure ...
• the method according to the invention may comprise one or more of the following characteristics:
• said fluid to be treated is essentially gaseous.
• said solid containing mainly CO2 formed in step a) and extracted in step b) is in the form of dry ice. It has the consistency of snow, which facilitates its extraction.
• cryo-condensation is carried out by depositing on one or more surfaces.
• said surfaces are the internal and / or external surfaces of tubes.
• said surfaces are the external surfaces of solid particles.
• said surfaces are oriented so that at least a portion of said solid falls periodically by the effect of gravity after a certain thickness of said solid has formed on said surfaces.
• said surfaces are periodically scraped to collect at least a portion of said solid as it is formed.
• said scraping is at least partially carried out by one or more endless screws.
• At least a portion of said surfaces is animated by a vibration movement promoting the detachment of at least a portion of said solid.
• At least a part of said surfaces is periodically heated in order to take off and to drop at least a portion of said solid.
• cryo-condensation of said solid takes place on solid carrier particles forming a fluidized bed.
• said solid carrier particles on which said solid has condensed in a first reactor are taken from said first reactor and then regenerated in a second reactor so as to rid them of at least a portion of said solid which they carry.
• said solid carrier particles are taken from said first and second reactors by gas-solid separation in cyclones.
• said solid carrier particles contain at least one metal and / or a plastic material, or contain mainly CO2.
• At least a portion of said solid is extracted in said step b) by the action of one or more worm.
• step a at least a portion of said solid is detached from said surfaces or said solid carrier particles on which it has condensed in step a), said detachment being obtained under the effect of pressure waves or assisted by pressure waves.
• a solid is formed and adheres to the walls of the enclosure in which the cooling of the mixture to be treated and its cryo-condensation occurs.
• these surfaces can be of variable shapes. They can be flat or left.
• the geometry of the enclosure is tubular, that is to say that the fluid to be treated circulates in hollow tubes and / or around hollow or solid tubes.
• the cryoncondensation occurs on the surface of particles of variable shapes, for example beads.
• the extraction of the solid that forms on these surfaces can be done in different ways. If the surfaces or particles on which the cryo- condensation takes place are mobile, it is not necessarily necessary to detach the solid. If these surfaces do not leave the enclosure where the cryocondensation occurs, then it becomes necessary to take off and transport the solid out of said enclosure.
• the surfaces in question are oriented so that the solid can fall under its own weight when a certain thickness has formed. It is also possible to scrape said surface by any mobile means of suitable shape audited surfaces. According to one particular embodiment, the scraping may be carried out by one or more endless screws placed close to said surfaces or in contact with said particles, at a distance such that the screw bites in or dislocates the layer of solid to be extracted.
• Said surfaces can also be heated to take off all or part of the solid. According to a particular embodiment, this heating is achieved by electrical tracing, that is to say by passing heating electric resistances in the structure of the enclosure.
• the cryo-condensation is carried out on particles in a fluidized bed. These particles are circulated from areas where cryo- condensation occurs to areas where the particles lose at least a portion of the solid layer formed on their surface.
• One possible embodiment consists in having one or more cryo-condensation reactors and one or more regeneration reactors between which said particles circulate. These particles are generally separated from the gas streams by cyclones. The regeneration of the particles may or may not comprise a cooling of said particles to a temperature below the temperature of the triple point of CO2.
• These particles may comprise different materials, in particular metal and / or plastic. They may comprise solid comprising predominantly CO2. In one embodiment, they enlarge or even appear in the cryo-condensation reactor and thin or even disappear in the regeneration reactor.
• the transport of the solid which has taken off from the chamber where the cryocondensation takes place may be provided by one or more augers.
• All the aforementioned means for taking off the solid deposited on said surfaces may be used alone or in combination.
• the invention also relates to the process applied to industrial fumes for the purpose of capturing CO2.
• these fumes come from an energy production plant (steam, electricity) and may have undergone pre-treatments.
• FIG. 1 schematically represents a CO2 capture unit implementing a method according to the invention
• FIG. 2 diagrammatically represents the cryo-condensation enclosure of an installation implementing a method according to the invention
• FIG. 3 shows schematically the use of a method according to the invention in a coal-based power generation facility.
• FIG. 1 implements the steps described below.
• the fluid 24 consisting of flue gas is compressed in a compressor 101, in particular to compensate for the pressure losses on the various equipment of the unit. Note that this compression can be combined with the so-called draw compression of the boiler giving rise to smoke. It can also be carried out between other stages of the process, or downstream of the CO2 separation process; the compressed fluid 30 is injected into a filter 103 to remove the particles to a concentration level of less than 1 mg / m 3 , preferably less than 100 ⁇ g / m 3 ;
• the dust-free fluid 32 is cooled to a temperature close to 0 0 C, generally between 0 0 C and 10 0 C, so as to condense the water vapor that it contains.
• This cooling is performed in a tower 105, with two-level water injection, cold water 36 and water at a temperature close to ambient 34. It is also possible to envisage indirect contact.
• the tower 105 may or may not have packings;
• the fluid 38 is sent to a residual water vapor removal unit 107, using for example one or both of the following methods: o adsorption on fixed beds, fluidized beds and / or rotary dryer the adsorbent may be activated alumina, silica gel or a molecular sieve (3A, 4A, 5A, 13X, ...); o condensation in a direct or indirect contact exchanger.
• the dried fluid 40 is then introduced into the exchanger 109 where the fluid is cooled to a close temperature, but in any case, greater than the solidification temperature of the CO2.
• This can be determined by those skilled in the art knowing the pressure and the composition of the fluid 40 to be treated. The latter is located at about -100 0 C if the CO2 content of the fluid to be treated is of the order of 15% by volume and a near atmospheric pressure.
• the fluid 42 having undergone first cooling 109 is then introduced into an enclosure 111 to continue cooling to the temperature which ensures the desired capture rate of CO2.
• a cryo-condensation of at least a portion of the CO2 contained in the fluid 42 occurs, so as to produce on the one hand a gas 44 depleted of CO2 and on the other hand a solid 61 comprising mainly CO2.
• the gas 44 leaves the chamber 111 at a temperature of the order of -120 ° C. This temperature is chosen according to the target CO2 capture rate. With this temperature, the CO2 content in the gas 44 is of the order of 1.5% by volume, ie a capture rate of 90% starting from a fluid to be treated comprising 15% CO 2.
• this enclosure 111 a continuous solid cryo-condensation exchanger in which solid CO 2 is produced in the form of dry ice, which is extracted for example by a screw and pressurized for cooling. introducing into a bath of liquid CO2 121, where there is a pressure greater than that of the triple point of CO2. This pressurization can also be performed in batches in a silo system. Continuous solid cryo-condensation can itself be carried out in several ways:
• scraped surface exchanger the scrapers being for example screw-shaped so as to promote the extraction of the solid
• Fluidized bed exchanger so as to cause the dry ice and clean the tubes by particles for example of density higher than that of the dry ice
• the fluid 46 is then reheated in the exchanger 109.
• the fluid 48 may also be used in particular to regenerate the residual vapor elimination unit (107) and / or to produce cold water (115) by evaporation in a tower with direct contact 115 where a dry fluid 50 is introduced which will saturate with water by vaporizing a part;
• the solid 62 comprising predominantly CO2 is transferred to a bath of liquid CO2 121;
• this bath 121 must be heated to remain liquid, to compensate for the cold input by the solid 62 (latent heat of fusion and sensible heat). This can be done in different ways: o by heat exchange with a hotter fluid 72, or by direct exchange, for example by taking a fluid 80 from the bath 121, by heating it in the exchanger 109 and re-injecting it into the bath 121. - the liquid 64 comprising mainly CO2 is taken from the bath 121.
• this liquid is divided into three streams.
• the first is obtained by an expansion 65 to 5.5 bar absolute producing a two-phase fluid, gas-liquid 66.
• the second, 68 is obtained by compression 67, for example at 10 bar.
• the third, 70 is compressed for example at 55 bar.
• the 5.5 bar level brings cold to a temperature close to that of the triple point of CO2.
• the levels at 10 bar allows the transfer of the latent heat of vaporization of the fluid 68 to about -40 ° C.
• the fluid 70 does not vaporize during the exchange 109. This allows a good valuation of the frigories contained in the fluid 64 during the exchange 109 while limiting the energy required to produce a stream of purified and compressed CO2 5;
• the primary fluids 66, 68, 70 are compressed to a pressure level higher than the critical pressure of the CO2 thanks to the compressors 131, 132, 133.
• FIG. 2 represents a cryo-condensation chamber 200 kept cold, in particular by exchange with a fluid 75 that can be the working fluid of a refrigerating cycle.
• the fluid to be treated 42 possibly pre-cooled, is introduced into the chamber 200.
• the fluid 42 cools further, a cryovial Condensation occurs, with deposition of a solid layer on the cold surface 210.
• the horizontal orientation of this surface 210 causes a portion of the solid layer 211 comprising mainly CO2 to fall from time to time.
• an endless screw 201 makes it possible to extract the solid 62.
• the gas that is poor in CO2 44 serves to cool the fluid 42 and / or to some of its cryocondensation.
• FIG. 3 represents a coal-based electricity generation installation, implementing various purification units 4, 5, 6 and 7 of the fumes 19.
• a primary air flow 15 passes through the unit 3 where the coal 15 is sprayed and driven to the burners of the boiler 1.
• a secondary air flow 16 is supplied directly to the burners to provide additional oxygen. necessary for an almost complete combustion of coal.
• Supply water 17 is sent to boiler 1 to produce steam 18 which is expanded in a turbine 8.
• Unit 4 removes NOx for example by catalysis in the presence of ammonia.
• Unit 5 removes dust for example by electrostatic filter and unit 6 is a desulfurization system for removing SO2 and / or SO3. Units 4 and 6 may be redundant depending on the composition of the required product.
• the purified flow 24 from unit 6 (or 5 if 6 is not present) is sent to a low temperature purification unit 7 by cryoponding to produce a relatively pure CO2 flow rate and a residual flow rate. enriched in nitrogen.
• This unit 7 is also called a CO2 capture unit and implements the method that is the subject of the invention, as illustrated, for example, by FIGS. 1 to 2.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Analytical Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Carbon And Carbon Compounds (AREA)
• Treating Waste Gases (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Separation By Low-Temperature Treatments (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40946666

Family Applications (1)

Country Status (5)

Families Citing this family (9)

Family Cites Families (11)

• 2008
  • 2008-12-19 FR FR0858863A patent/FR2940412A1/fr active Pending
• 2009
  • 2009-12-14 WO PCT/FR2009/052506 patent/WO2010076464A1/fr not_active Ceased
  • 2009-12-14 CN CN2009801511745A patent/CN102257341A/zh active Pending
  • 2009-12-14 EP EP09803848A patent/EP2379969A1/de not_active Withdrawn
  • 2009-12-14 US US13/139,003 patent/US20110296866A1/en not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events