CS240829B1 - A method for producing coke gas ammonia and apparatus for making the same - Google Patents

Abstract

The essence of the method and device is that the coke oven gas is first compressed to a pressure of 0.3 to 1.2 MPa, after which hydrogen sulfide and other impurities are removed from it by washing with methanol. After further compression to a pressure of 1.5 to 4 MPa, the coke oven gas is subjected to a sol with air separately compressed for catalytic conversion of hydrocarbons, conversion of carbon monoxide, after which, after removal of carbon dioxide by washing with methanol, excess nitrogen by partial condensation and the remainder of carbon monoxide by methanization, the nitrogen-hydrogen mixture thus formed is compressed to the pressure of ammonia synthesis.

Description

The present invention relates to a method and apparatus for producing ammonia from coke oven gas with complete conversion of coke oven gas components to hydrogen.

Kofcsárenský gas is available at atmospheric pressure and contains a knee of 60 vols of hydrogen, 25 of methane, 2.5 of higher hydrocarbons, 6 of carbon monoxide or nitrogen, oxygen, carbon dioxide, hydrogen sulfide and a number of other additives such as phenol, diesel flax, organic sulfur, hydrogen cyanide, acetylene and ammonia.

A number of methods for converting coke oven gas into ammonia are known. The most industrially used method to date is to coke gas to a pressure of 1 to 2 NPa, to remove unwanted impurities (CO 2, H 2 S) (fCN) by washing with different absorbents and to separate the hydrogen from other impurities by cooling to low temperatures followed by hydrogen scrubbing. Pure nitrogen gas mixture is compressed to a pressure of about 3 HPa to produce ammonia synthesis, efforts have been made to simplify purification and low temperature separation by replacing selective scrubbing with methanol scrubbing, and it is also known to purify coke oven gas in regenerators which further reduces compression problems Coke oven gas contains components that polymerize at higher temperatures.

The main disadvantage of all low-temperature coke oven gas separations, however, is that a large amount of other gases leaving the separation at low pressure are compressed with hydrogen. The energy consumption for ammonia production is therefore high.

It is also known to separate coke oven gas impurities from hydrogen by adsorption. From the point of view of energy consumption, this method is not more advantageous than the low-temperature divisions, because like

240 829

- 2 níz low temperature separators leave hydrogen admixtures at low pressure · Navio hydrogen yield is significantly lower, knife at low temperature separator.

From an energy point of view, it is preferable to convert the non-lance and other hydrocarbons and the carbon monoxide into the hydrogen state. In another embodiment, the coke oven gas is subjected to hydrogenation followed by removal of hydrogen sulfide after compression, and after preheating, together with an oxygen-enriched air flue, enters the reactor at a knee temperature of 1000 ° C to react the hydrocarbon blades, feathers and oxygen to form hydrogen. carbon monoxide and carbon dioxide. After removal of the carbon monoxide by conversion with a water feather and after removal of carbon dioxide in the absorbent, the last carbon monoxide and carbon dioxide residues are removed by methanization. The bicarbonate mixture containing Inert up to 1 Z is compressed to the ammonia synthesis pressure. However, this solution still has the following disadvantages: it must be available if the foot oxygen is present, the difficulty of compressing the coke oven gas remains longer and the nitrogen-containing feed produced contains a large amount of inert substances.

There is also known a process for processing coke oven gas to ammonia, which consists of compression to 0.4 MPa, ammonia water and oil scrubbing, hydrogen sulphide removal by absorption and adsorption on activated carbon, longer from compression to 0.62 MPa, from steam reforming, secondary air reforming, from carbon monoxide conversion, from carbon dioxide scrubbing to water, from compression to 11 MPa, from carbon monoxide and carbon dioxide doping, from compression to ammonia synthesis pressure, and from ammonia synthesis itself. This method has the disadvantage that it requires the heating of the reforming tubes to which coke oven gas without pretreatment is not suitable due to the high sulfur compound content. Desulphurisation means a significant increase in operation costs. The use of other fuels for heating means dependence on another energy source, and this entails additional costs. A further disadvantage is that the nitrogen-containing mixture contains a large amount of inert. At a high inert content, the ammonia synthesis effluents must either be incinerated or separated in a separate installation.

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Disadvantages of the known methods for producing aalakol from coke oven gas, consisting of gas compression, scrubbing of absorbent gas, for example aethanol, in the catalytic conversion of hydrocarbons and carbon monoxide, low temperature separation, the coke oven gas is first compressed to a pressure of 0.3 to 1.2 NPa, after which the aethanol is removed from the coke oven gas at -20 ° C to -50 ° C hydrogen sulfide, organic sulfur, hydrogen cyanide, benzene and salarizing hydrocarbons, whereupon the coke oven gas is compressed to a pressure of 1.5 NPa to 4 NPa, at which, after heating to 400 ° C to 600 ° C, the air is separately compressed and rotated to the same temperature, and the added feathers are heated together with the coke gas if necessary, or evaporate and heat the added water, subjecting it to a catalytic conversion of hydrocarbons at a temperature of 800 ° C to 1200 ° C to form hydrogen, carbon monoxide and carbon dioxide, followed by conversion of carbon monoxide at 250 ° C to 500 ° C, and after cooling to -30 ° C to -60 ° C, the carbon monoxide was removed and the carbon dioxide was removed, followed by ocblazenia to - 170 ° C to -185 ° C removes excess nitrogen by partial condensation, and the resulting hydrocarbon sauste is subjected to catalytic synthesis to aaon1ak after heating, aethanizing the remaining carbon monoxide and pressurized to 10 NPa to 40.NPa, separating the mixture of ethanol and water from the scrubbing of hydrogen sulfide 1 from carbon dioxide scrubbing is carried out in the recovery of ethanol from the scrubbing of hydrogen sulfide, and the aaonlak synthesis fumes are returned before or after carbon dioxide scrubbing.

Apparatus for carrying out said method, comprising coapressors, scrubbers, reactors, regeneration columns and heat exchangers, is characterized in that the coke oven gas coapressor is connected to a coke oven gas scrubber connected to a coke oven gas purge recovery column and for a longer time with a coke gas compressor. is further coupled to a hydrocarbon converter to which an air coapressor is simultaneously connected, wherein the hydrocarbon converter is further coupled to a carbon monoxide converter and, for a longer time, to an oxide scrubber;

- 4 240 829 carbon dioxide combined with a carbon dioxide scrubber recovery column, whereupon the carbon dioxide scrubber is also associated with a low-temperature partition, reactor · otanlzaco reactor, compressor · nitro-hydrogen and an reactor · synthesis of anonlake, quenched carbon dioxide scrubbing are interconnected ·

Advantage of the method and apparatus for producing anonlac from coke oven gas according to the invention is simple apparatus with low energy consumption · Difficult gas compression with respect to polyne rad remains only in the first degree of compression to a pressure of 0.4 to 1.2 HPa · Other compression is already free from these problems after washing Methanol ·.

Furthermore, the process according to the invention does not require the separation of air for which the use of oxygen had to be found in the prior art in order to be able to produce pure nitrogen as a by-product. A single absorbent is used to wash the sulfur compounds and carbon dioxide. The regeneration of the absorbent may be partially common. While removing the excess nitrogen at the low-temperature partition, all of the non-ethane, two-thirds of argon, and nearly half of the carbon monoxide are removed simultaneously. After carbon monoxide which has been consumed with less hydrogen than with conventional equipment, only aa1 of 0.3% of the inert gases remains in the nitrogen dioxide feed. Returning synthesis flue gases to a low temperature equipment, i.e., carbon dioxide scrubbing «ethanol · ·, or catalytic processes, can utilize hydrogen from the flue gas without the need for additional overnight equipment.

By using the process for producing anonlaked coke gas according to the invention in the described apparatus, the coke gas consumption per unit of produced anonlak is reduced to less than half (about 45 Z) compared to the low temperature hydrogen and gas scrubbing apparatus liquid nitrogen. Although the heat consumption of the coke oven gas will increase by about 10 Z, the energy consumption for coke oven gas and air versus coke oven gas and nitrogen compression for low temperature hydrogen separation is reduced by about 30 Z, and more steam is produced which the knife can be used for example5

240 829 Ammonia Cooling System for Methanol Gas Washing.

This will result in additional · energy savings ·

Using the process and apparatus for producing ammonia from the coke oven gas according to the invention, pure carbon dioxide can be produced which can be a welcome raw material for the production of urea.

An embodiment of a method and apparatus for producing enonlact from a coke oven gas is shown schematically in the drawings. Fig. 1 shows a basic block diagram of the production of ammonia from coke oven gas according to the invention and Fig. 2 is supplemented by foot bonds other than methanol regenerations and waste back to production.

The apparatus in FIG. 1 consists of a coke oven gas compressor 2, connected to a coke oven scrubber 2, which is further connected to a coke oven gas recovery column 4 and a coke oven pressurizing compressor 4. The coke gas compressor 4 and the air compressor 2 are connected to a hydrocarbon converter 6 which is connected to a carbon monoxide converter 6 and further to a carbon dioxide scrubber 8 connected simultaneously to a carbon dioxide washing column 9. The carbon dioxide scrubber 6 is further coupled to a low-temperature nin gas partition 10, a non-tanning reactor 11, a compressor 12 of the nitrogen mixture and an ammonia synthesis reactor 13. The labels refer to prominent apparatuses. Heat exchangers, coolers, digesters, separators, etc. not shown in the figure.

The coke oven gas is compressed from atmospheric pressure of the coke oven gas compressor 2 to a pressure of 1.0 MPa / 0.3 to

1.2 MPa /. At this pressure, the coke oven gas passes through a scrubber 2 where methanol-hydrogen sulfide and organic sulfur are removed at -20 ° C to -50 ° C. This also removes benzol, water, hydrogen cyanide, higher hydrocarbons and part of the carbon dioxide. The gas thus cleaned is compressed in a coke oven pressurizer 4 to a pressure of 3 MPa (1.5 to 4 MPa). At this pressure, the coke oven gas is heated to a temperature of 400 to 600 ° C, and then introduced into the hydrocarbon converter 6 together with air compressed to the same pressure in the compressor 2 ^{and also} heated to a temperature of 400 to 600 ° C. Coke oven gas or 1 air,

240 comprises an inlet axis to the water vapor converter 6, which is added as water vapor or water vapor is supplied from the gas or the vapor. air before heating. The catalyst undergoes a chemical reaction, other than hydrocarbons, the bulk of which is Methane, steam and oxygen to form hydrogen, carbon monoxide and carbon dioxide. The resulting gas mixture, after cooling, is introduced into the carbon monoxide converter 7, where at a temperature of 250 to 500; ®C reacts on the catalyst with carbon monoxide and water vapor to form hydrogen and carbon dioxide. After cooling, the gas thus treated is scrubbed with methanol in a carbon dioxide scrubber at a temperature of -20 ° C to -60 ° C. The cooled and cleaned gas, containing only about 10 ppP CO _2, enters the low temperature gas partition 10, where cooling to -170 ° C to -185 ° C (depending on the pressure) condenses the excess nitrogen and virtually all of the netane, two one-third of argon and almost half of carbon monoxide. The resulting hydrocarbon feed, containing 75 Z hydrogen and 25 Z nitrogen, contaminated with even a small amount of carbon monoxide and argon, after heating to 100 ° C to 200 ° C, passes through a reactor · 11 non-lysis where the carbon dioxide reacts with hydrogen to form a catalyst. Nethan and water vapor.

After cooling to ambient temperature, the synthesis mixture thus formed is compressed in a compressor 12 of the hydrogen chloride mixture to anonlase synthesis pressure (10 to 40 MPa). In the ammonia synthesis reactor 13, ammonia is produced on the catalyst as the final product. In the synthesis of anonlake, the inert gases contained in the feed synthesis mixture are concentrated by not entering the reaction. In order not to increase the Inert concentration too much, some of the gas is vented from the anonlak synthesis ring. The methanol scrubbing, which takes place in the coke oven scrubber 2, has a separate methanol recovery in the coke oven gas purification column 3, representing a variety of columns, heat exchangers, coolers and digesters.

Upon regeneration, benzene, water and acid gases are separated from methanol, which can be converted to elemental sulfur or sulfuric acid. The methanol scrubbing in the scrubber, carbon dioxide 8, has a separate methanol recovery in the recovery column. During regeneration, water, fuel gas and almost pure carbon dioxide are separated from the methanol.

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Fig. 2 shows the basic block diagram of coke oven gas production as in Fig. 1 with the same marking of the individual equipment, but with additional footbinding, which contribute to the simplification and efficiency of the production. The carbon dioxide is introduced for regeneration into a coke oven gas purification column 3 where ee regenerates at the same time as the ethanol / water from the coke oven gas scrubber 2. A portion of the heat-completely recovered non-ethanol from the coke oven gas purification column 8 is returned to the carbon dioxide scrubber 8. The charged methanol from the carbon dioxide scrubber 8 is throttled in the recovery column 6 first to a pressure corresponding to the suction pressure of the coke gas pressurizer 4. Throttling · The released gas, containing large amounts of carbon dioxide and a large amount of hydrogen, returns to the suction of the shielded pressurizing compressor 4. This can substantially reduce the loss of hydrogen during the methanol scrubbing. Similarly, the gas released when methanol is throttled from the coke oven scrubber 6 to the coke of the first or second stage of the coke gas compressor 2 (not shown in FIG. 2) may be used for scrubbing coke gas in the scrubber. 8 and the completely recovered methanol from the recovery column 2 is returned to the scrubber 8. The exhausts from the anonlase synthesis reactor 13 are returned to the discharge of the coke gas pressurizing compressor 6, optionally after the carbon dioxide scrubber 8, respectively. T1n can be recycled not only to the hydrogen contained in the blowers, but to convert 1 contained therein to hydrogen (in the case of returning to the discharge compressor 6), while the returned argon is removed in a low-temperature gas partition 10 "

Using the process and apparatus for producing anonlaked coke gas according to the invention, pure carbon dioxide can be produced, which can be a welcome raw material for the production of urea.

Claims (2)

SUBJECT MATTER 240 829 A process for producing ammonia from a coke oven gas, comprising compressing a gas, scrubbing gas with an absorbent, such as methanol, catalytic conversion of hydrocarbons and carbon monoxide, low temperature separation, methane and a catalytic synthesis of anonlak, characterized in that the coke oven gas is first compressed no pressure of 0.3 to 1.2 MPa, after which it is removed by washing · Methanol · at -20 ° C to -50 ° C hydrogen sulfide, organic sulfur, hydrogen cyanide, benzine and pitch-forming hydrocarbons, whereupon the coke oven gas is compressed to a pressure of 1.5 to 4 MPa at which, when heated to a temperature of 400 ° C to 600 ° C, together with the air, is compressed separately and heated to the same temperature, with the addition of coke oven gas and optionally air heated or evaporates and heats the added water, subjected to a catalytic conversion of hydrocarbons at a temperature of 800 ° C to 1200 ° C to form hydrogen, carbon monoxide and carbon dioxide, and at 250 ° C to 500 ° C undergoes conversion of carbon monoxide and after cooling to -30 ° C to -60 ° C, the carbon dioxide is removed by washing · methanol · then cooled to -170 ° C to -185 ° C removes the excess nitrogen by partial condensation, and the resulting hydrocarbon mixture is subjected to catalytic synthesis to ammonia after heating, non-fuming the remaining carbon monoxide and pressurized to 10 to 40 MPa, while separating methanol / water from hydrogen sulfide scrubbing 1 from carbon dioxide scrubbing. in methanol recovery from hydrogen sulphide scrubbing and ammonia synthesis separation, it returns before catalytic hydrocarbon conversion or after carbon dioxide scrubbing. 2. Apparatus for carrying out the method according to claim 1, comprising compressors, scrubbers, reactors, regeneration columns and heat exchangers, characterized in that the coke oven gas compressor (1) is connected to a coke oven scrubber (2) connected to the regeneration column (3). cleaning of coke oven gas and further a coke oven pressurizer (4), which is further connected to a hydrocarbon converter (6), - 9 240 829 to which an air compressor (5) is connected at the same time, the hydrocarbon converter (6) being further coupled to a carbon monoxide converter (7) and a carbon dioxide scrubber (8) coupled to the scrubbing column (9). The carbon dioxide scrubber (8) is further associated with a low temperature gas separation (10), a methanization reactor (11), a nitrogen gas compressor (12) and an ammonia synthesis reactor (13), wherein the recovery coke (3) purification column and the carbon dioxide scrubbing column (9) are interconnected.