SU734175A1 - Method of coke gas purification - Google Patents

Description

This invention relates to industrial methods for purifying coke oven gas. There is a known method of purifying coke oven gas going to produce ammonia and these penbenzene i, in accordance with which the crude gas is first compressed in compressors to a pressure of 16-19 atm, after which the gas is subjected to multi-stage purification under a pressure of 16 to 18 at. At the first stage, the gas is cleaned of nitric oxide by oxidation in hollow devices at the SO, ISRS; on the second, to remove benzene hydrocarbons and naphthalene, the hei is washed with salt oil at a temperature of 35-4.0 ° C; in the third, carbon dioxide and hydrogen sulfide are cleaned in scrubbers irrigated with ammonia water; the fourth is washed with water to remove ammonia; on the fifth, they are purified by alkali from residual amounts of carbon dioxide, hydrogen sulfide and hydrogen cyanide; in the sixth, acetylene and residual amounts of nitric oxide are purified by catalytic hydrogenation at 16 0-22 o C. Hydrogen sulfide, mercaptants and carbon dioxide formed during catalytic hydrogenation at the seventh purification stage are absorbed in an alkali solution. After that, coke oven gas is fed to low-temperature fractionation into separation devices. The disadvantages of this method of purification of coke oven gas include: multi-stage, high energy consumption, insufficient degree of gas purification, large losses of ethylene (2O-50%), due to the presence of a hydrogenation unit in the purification scheme, the formation of a large amount of wastewater. In addition, gas purification by a known method results in the deposition of resinous substances in the cylinders and interstage refrigerators of compressors, due to the presence in the coke oven gas of a misty resin and resin-forming components, such as diene and higher acetylene hydrocarbons, butylenes and nitrogen oxides. By this

This causes compressors to wear out quickly and require frequent repairs.

The closest to the described invention to the technical essence and the achieved result is the method of CLEANING coke oven gas from impurities of smudy substances, nitric oxide, acetylene-MJX, diene, aromatic, acidic and sulfur compounds, including compressed gas and subsequent washing with tributyl phosphate at 1220 pressure. from O. to -50 from 21.. The disadvantages of this method of cleaning gas are: the deposition of resinous substances in the cylinders and interstage refrigerated compressors, due to the lack of very good gas sources from resins and resin-forming components before gas supply for compression; insufficient gas purification from acidic compounds such as carbon dioxide, hydrogen sulfide and nitrous oxide. The noted deficiencies do not allow this method to be applied to the purification of the coke oven gas used to produce ammonia and ethylbenzene. The aim of the invention is to increase the degree of purification. The aim of the invention is achieved by the method of purifying coke oven gas from impurities, tar, nitric oxide, acetylene, diene, aromatic, acidic and sulfur compounds, washing it with 70-1OO% sulfuric acid containing 1- 10 g / l of ferrous sulphate at 30-40 0 and pressure of 1-4 atm, followed by compression, washing with 10-25% ethanolamine solution in diethylene glycol at 30-4 ° С and pressure of 12-2О at and tributyl phosphate at pressure 12-2 O ata and temperature from O up to -50 ° C. This method allows to achieve the required degree of purification of coke oven gas, after directing the gas to the low-temperature fractionation, to the gas separation unit. The drawing shows a setup for implementing this method of cleaning coke oven gas used for the production of ammonia and ethyl benzene. Coke oven gas through line 1 after drying is supplied under pressure from 1.04 to 4.5 atm down column 2, where it is washed at a temperature of 30 4 ° C 70-1OO% sulfuric acid with the addition of ferrous sulphate in an amount of from 1 to 1O. On 1 liter of acid. At the same time, gas purification from resin-forming components is carried out through polymerization processes.

diene and higher acetylenic hydrocarbons, alkylation of gas benzene hydrocarbons with butylenes and other heavy unsaturated compounds. In the final stage, all resinous and other products are washed out of the coke oven gas with sulfuric acid. Gas purification from nitric oxide occurs due to the binding of nitric oxide in complex with ferrous sulphate.

Partial regeneration of the spent sulfuric acid solution is carried out by heating it to a temperature above 9 ° C when stripping with an inert gas, such as nitrogen. Under these conditions, the decomposition of the nitric oxide complex with ferrous sulphate occurs and the excretion of the oxides of azt with the stripping gas is removed. To this end, a solution of sulfuric acid from the column 2 by the pump 3 is fed through a heater 4 to 5, where the regeneration process takes place. The regenerated solution from the bottom of the column 5 is taken by the pump 6 and fed through the heater 7 to the top of the column 2. During operation, continuously or intermittently part of the spent acid is removed from the cleaning cycle through line 8 and is used, for example, to capture ammonia from coke oven gas sulphate separation. The acid loss is replenished with fresh acid through line 9. After column 2, the coke oven gas is sent through line 10 to column 11 for flushing water from splashes of entrained acid. The main amount of water is circulated through column 11 by means of a pump 12. Part of the acidic circulation water is output t from the cycle through line 13 and fed to the sulphate compartment, and the loss of water is replenished by the freshness of the top of the column 11 with fresh water, which is supplied by the pump 14. Next, the coke oven gas through line 15 is sent to the compressors 16 and after compression in the compressors to a pressure of 2 ata under They are drained of moisture and purified from acidic components in column 17, where the gas is washed with a 10–25% solution of ethanolamine in diethylene glycol at a temperature of 30–40 ° C and a pressure of 12–20 ata. The spent ethanolamine (EA) solution in diethylene gipope (DEG) is taken from the bottom of the column 17 and fed through the throttle valve 18 and the heat exchanger 19 to the regeneration unit in the column 20. The solution is regenerated under vacuum when heated to 10 ° C. The regeneration gases through line 21 containing water vapor, benzene hydrocarbon vapors, naphtha lin, sour gases are directed to the air intake. The regenerated solution from 1shzhnaya part of the column 20 is pumped by pump 22; through the cooler 23 to the top of the spattes 17. Part of the solution is taken out of the cleaning cycle for vacuum distillation. The loss of solution replenish with fresh solution. After the column 17, coke oven gas via line 24 is fed down to the column 25 to cool and purify the gas from the apetylene and dumb components by washing with tributyl phosphate at a temperature of -10 D and a pressure of 2 O atom, followed by a coconut gas with the specified temperature and pressure through the line 28 served in the low-temperature fractionation unit 27, the spent tributyl phosphate from the column 25 is fed through the throttle valve 28 and the preheater 29 into the tank 30, where the pressure is maintained at about 6 atmospheres. The gases released during the release of pressure, containing ethylene and propylene, are discharged through the throttle valve 31 to the inlet of the compressor 16, and the spent tributyl phosphate from the DF tank is fed through the throttle valve 32 and the preheater 33 to the top of the soluble ethylene and propylene stripper 34. Ethylene and propylene are blown off at elevated temperatures under a pressure of about 4 at. An ethylene fraction coming in about 35 from coke oven gas separation unit 27 is used as the stripping gas. The entire ethylene fraction coming out of the top of column 34 is sent to these foreheads for purification and use as a raw material for the synthesis of ethylenebenzene and isopropylbenzene. From the shzhnoy part of the column 34, the spent tributyphosphate is fed for regeneration through the throttle valve 36 and the heater 37 to the column 38. The regeneration of the spent tributyl phosphate is carried out by heating and blowing off the harmful impurities of carbon monoxide or methane fractions coming from the unit under thermal temperature fractionation of the coke gas of the co-gas. , purge gases 7,756 along with exhausted harmful impurities are fed to the rich gas collector. The regenerated tributyl phosphate is taken from the bottom of the column 38 by a pump 4O and fed through the cooler 41 to the column 25. In the gas purification process, the loss of tributyl phosphate is compensated for by feeding fresh tributyl phosphate into the cycle. The extraction of nitric oxide from gases is based on the formation of complex compounds with ferrous sulphate, therefore the concentration of the latter will be determined by the concentration of nitric oxide in the gas to be purified. The optimum temperature for the process of absorption of nitrogen oxides with a solution of ferrous sulfate is a temperature ranging from 10 to. To ensure the simultaneous purification of coke oven gas from nitric oxide to sulfuric acid of a specified concentration, it has been proposed to add from 1 to 10 grams per liter of ferrous sulphate. It should be noted here that the concentration of ferrous sulphate is determined by the amount of nitric oxide in the gas and does not affect the chemistry of the process. The temperature of the washing of coke oven gas with this solution, taking into account the peculiarities of the processing technology of coke oven gas, must be taken in the range from 30 to 40 ° C7. This method of gas cleaning has been tested on a model plant. The model installation scheme, the composition of the temperature of the openings, as well as the pressure in the absorption columns are similar to the implementation of the proposed method in industry. The diameter of the absorption columns is 80 mm, height 1000 mm. Gas consumption for installation -3.5. Consumption of 7O% and 1OO% sulfuric acid with the addition of 2 g / l of ferrous sulphate of ferrous iron 2O l / h of ethanolamine in diethylene glycol 24 l / h, tributyl phosphate 43 l / h. The results of purification of coke oven gas are presented in table. I and 2. For comparison, table. 1 also shows the results of cleaning coke oven gas by a known method.

S

a

to

"

YU

tS

h

The results of the test of the claimed method of purification of coke gas with the use of 100% sulfuric acid and 10% ethanolamine in diethylene glycol in the purification scheme

As can be seen from the table. 1.2, when purifying coke oven gas by the proposed method, complete cleaning of all harmful impurities is achieved.

Using this method for fine cleaning of coke oven gas in nitrogen-fertilizer plants will significantly simplify existing purification schemes, eliminate tar deposits in compressors, eliminate the consumption of ethylene and propylene during purification, increase the productivity of coke oven gas separation aggregates, eliminate harmful sources and reduce material and energy costs. All this in the final stage will reduce the cost of production of ammonia based on coke oven gas by 2-30%,

invention formula

The method of purification of coke oven gas from impurities of resinous substances, nitrogen oxides, acetylene, diene, aromatic, acidic and sulfur compounds, including compression of the gas and the subsequent

washing with tributyphosphate at a pressure of 12-2 O at and a temperature from 0 to, characterized in that, with a chain of increasing gas purification, the latter is washed with 70% s 1oo% sulfuric acid containing 1-10 g / l of ferrous sulphate prior to compression at 30-40 C and addition of 1-4 at and after compression. pre-served for washing 10-25% solution of

ethanopactin in diethylene glycol at 3040 C and a pressure of 12-20 at.

Sources of information taken into account in the examination

1, Semenova T, A. Purification of process gases, Himi, M ,, 1969,

with. 20-24.

2. USSR author's certificate

. 32l041j cl. On 01 D 53/14, 1970 (prototype).

Claims (1)

Claim The method of purification of coke oven gas from impurities of resinous substances, nitric oxide, acetylene, diene, aromatic, acidic and sulfur compounds, including gas compression and subsequent 11 734175 12 washing with tributyl phosphate at a pressure of 12-20 at and temperature from 0 to -50 ^ 0, characterized in that, in order to increase the degree of gas purification, the latter is washed before compression 1OO% — sulfuric acid containing 1-10 g / l of ferrous sulfate at 30-40 C and the addition of 1-4 ata and after compression. pre-served for washing with a 10-25% solution of ethanol min in ethylene glycol at 3040 C at a pressure of 12-20 at.