THE METHOD OF PURIFICATION OF GASES FROM ACIDIC COMPONENTS USING SOLUTIONS OF ALKALINE HYDROXIDES

ABSTRACT

In the article, the absorption method of cleaning gases "ELSOR" refers to the field of chemical technology, namely to processes of absorption purification of gases from sulphur-containing impurities, and can be used in gas purification processes of different composition and different origin, including natural, associated and process gases, in particular biogas, associated gas of oil fields, fuel gases supplied to facilities of heat and power facilities, ventilation and process gas emissions (salvo and regular) at facilities of the chemical, petrochemical industry, as well as in the production of special equipment and ammunition containing hydrogen sulfide and mercaptans

АННОТАЦИЯ

В статье абсорбционной метод очистки газов "ЭЛСОР" относится к области химической технологии, а именно к процессам абсорбционной очистки газов от серосодержащих примесей, и может быть использован в процессах очистки газов различного состава и различного происхождения, в том числе природных, попутных и технологических газов, в частности биогаза, попутного газа нефтяных месторождений, топливных газов, поступающих на объекты теплоэнергетических хозяйств, вентиляционных и технологических газовых выбросов (залповых и регулярных) на объектах химической, нефтехимической промышленности, а также в производстве спецтехники и боеприпасов, содержащих сероводород и меркаптаны.

Keywords: crude gas, solution, sodium hydroxide, absorbent, flow rate, concentration.

Ключевые слова: сырой газ, раствор, гидроксид натрий, абсорбент, расход, концентрация.

Substance is method of purifying gas from sulfur-containing impurities includes preparing an alkali metal hydroxide solution from an initial alkali metal sulfate solution, contacting the gas with an alkali metal hydroxide solution to obtain a saturated alkali metal hydroxide solution, and regenerating it. The initial solution of alkali metal sulfate with a concentration of 10-15% is fed into the anode and cathode chambers of the diaphragm electrolytic cell using a microporous diaphragm made of ceramic based on zirconium oxide or made of ceramic based on zirconium oxide containing additives of aluminum and yttrium oxides. In this case, the alkali metal hydroxide solution obtained in the cathode chamber is directed to contact with the gas, and the acid solution obtained in the anode chamber is fed to the regeneration of the saturated alkali metal hydroxide solution. This method allows to increase the degree of purification from sulfur-containing impurities and reduce energy costs.

The "ELSOR" method belongs to the field of chemical technology, namely to the processes of absorption purification of gases from sulfur-containing impurities, and can be used in the purification of gases of various composition and origin, including natural, associated and technological gases, in particular biogas, associated gas from oil fields, fuel gases supplied to thermal power facilities, ventilation and technological gas emissions (volley and regular) at chemical, petrochemical industry facilities, as well as in the production of special equipment and ammunition containing hydrogen sulfide and mercaptans.

The cleaning method "ELSOR" provides the highest quality of cleaning, because. solutions of alkali metal hydroxides are the best absorbents of H2 and other sulfur-containing impurities, it is economical, since the consumable material for the cleaning process is only electricity and the cleaning process is carried out at low temperatures, and the production of sodium hydroxide from the initial solution and the regeneration of the solution saturated with acid gases after cleaning carried out using the same electrochemical reactor, i.e. the electric energy spent on obtaining the absorbent also ensures its regeneration. In addition, the "ELSOR" method can be arried out both in stationary and in mobile units.

The method is implemented using the installation shown in the figure.

Figure. 1. Installation for gas purification from sulfur-containing impurities contains: diaphragm electrochemical reactor 1, diaphragm-separated 2 to the cathode 3 and anode 4 chambers, capacity 5 for the accumulation of an alkaline solution, capacity 6 for accumulation of sulfuric acid, absorber 7 and desorber 8. The installation also contains a mixer 9, pumps 10 and 11, a throttle valve 12 and gas and hydraulic piping, including inlet and outlet pipes

The cathode chamber 3 of the reactor 1 and the container 5 are filled with the initial aqueous solution of alkali metal sulfate. The anode chamber 4 of the reactor 1 and the container 6 are filled with the initial solution - an aqueous solution of alkali metal sulfate. The electrodes of the reactor 1 (not shown) are energized and the pumps 10 and 11 are turned on. In the process of electrolysis, the initial solution of alkali metal sulfate is subjected to electrochemical action in the cathode chamber 3, converting it into alkali metal hydroxide, which is accumulated in vessel 5. At the same time, a solution of sulfuric acid formed in the anode chamber 4 of reactor 1 is accumulated in vessel 6. Alkali metal hydroxide solution from vessel 5 is supplied by high pressure pump 10 to the upper part of absorber 7, into the lower part of which enters the raw gas to be purified. The acidic components contained in the gas interact with the absorber - an alkali metal hydroxide solution, and the purified gas is removed from the upper part of the absorber 7.

The saturated absorbent solution is withdrawn from the lower part of the absorber 7 through the throttle valve 12 and sent to the mixer 9, into which the sulfuric acid solution is supplied from the container 6 by the pump 11. In the mixer 6, the processes of regeneration of the absorber and the release of absorbed impurities take place. The gas-liquid mixture from the mixer 6 is fed into the desorber 8, from the upper part of which acid gases are removed, and from the lower part - an alkali metal sulfate solution, which again enters the cathode 3 and anode 4 chambers of the reactor 1.

Таble 1.

The amount of NaOH required to remove hydrogen sulfide from a 1000 nm gas at any ratio of CO₂:H₂S

Таble 2.

Performance indicators of the installation for the electrochemical synthesis of sodium hydroxide and sulfuric acid from a solution of sodium sulfate with a capacity of 10 kg of NaOH per hour

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