Sulfur in coal gasification process with inorganic sulfide (H2S) or organic sulfide (COS) in the form of conversion to gas phase. Organic sulfide at high temperature and can be almost completely converted into hydrogen sulfide. Therefore, in general, most of the sulfur crude gas exists in the form of hydrogen sulfide, crude gas desulfurization process of hydrogen sulfide removal mainly around the problem.

Hydrogen sulfide is a colorless gas with nasal odor at room temperature, its density is 1.539kg/m3. Hydrogen sulfide and its combustion products of sulfur dioxide will cause the air pollution on the human body, the poisonous air, containing 1% hydrogen sulfide will endanger human life. In addition, hydrogen sulfide and its combustion product harm lies in serious corrosion of gas pipeline, gas related equipment. Gas desulfurization process can not only improve the quality of the gas, to process the use of standard, but, also has the positive significance to strengthen the environmental protection of human.

The coal gas desulphurization method according to the material form can be divided into wet desulfurization process and dry desulfurization process. The desulfurization agent in wet desulfurization process of a liquid, easy to transport, easy to form a continuous cycle of desulfurization process. Therefore, the general wet desulfurization process is suitable for high efficiency and large capacity of gas desulfurization process.

The process can be divided into general wet desulfurization desulfurization absorbing gas in hydrogen sulfide and sulfur sorbent regeneration analysis of two stages. According to the properties of absorption and regeneration methods, can be divided into wet desulfurization technology of chemical absorption method, physical method, chemical and physical absorption of several types of comprehensive absorption etc..

Chemical absorption method of oxidation, neutralization method. Oxidation is catalyzed by the oxygen carrier in desulphurization agent, absorption of hydrogen sulfide in coal gas will be the formation of sulfur removal and, finally air regeneration desulfurization solution, a continuous cycle of desulfurization process is formed. Improvement of anthraquinone two sulfonic acid sodium method of city gas industry (modified ADA method), naphthaquinone method, picric acid method and Jing titanium cobalt sulfonate method (PDS method) are oxidation desulfurization, and early arsenic alkali method. In dilute alkali neutralization method for desulfurizing agent, forming compound reacts with hydrogen sulfide, and the removal of hydrogen sulfide in coal gas. When the absorption liquor temperature increases, the pressure is reduced, in front of the formation of compound decomposition, release hydrogen sulfide, solution regeneration. Alkyl alcohol amine method and alkaline salt solution method such as.

The desulfurization process of physical absorption method is a purely physical dissolution, release process, for example, the low temperature methanol desulfurization of high pressure gasification belongs to this kind of. It is the absorption liquid with organic solvent methanol, which in the state under high pressure and low temperature of hydrogen sulfide in gas absorption ability, achieve the effect of gas desulfurization. When the absorption liquid pressure heating, the absorbed hydrogen sulfide released, the solution regeneration, continue to participate in the desulfurization.

The physical, chemical comprehensive absorption natural gas purification sulfolane desulfurization plant widely used. By using the method of sulfolane aqueous mixtures of Sulfolane and alkyl alcohol amine as the absorbent, the absorption equilibrium line showed low acid concentration, has the characteristics of chemical absorption effect of acidic components, and in the condition of high acid concentration, absorbent has obvious physical absorption. After the absorption of rich liquid is heated, releasing acidic gas, absorbent regeneration.

Dry desulfurization of iron oxide, Zinc Oxide method, active carbon method etc.. Desulfurizing agent in dry desulfurization technique is the solid material, the low sulfur value generation. In general, solid material continuous recycling operation is difficult, therefore, often uses periodic intermittent operation, which restricts the desulfurization ability, not suitable for processing high sulfur content gas. However, because the process of dry desulfurization process are relatively simple, and can achieve a higher desulfurization depth, it is welcomed by many users, the desulfurization of coke oven gas, coal gasification with dry distillation method of iron oxide city gas industry, or with the wet desulfurization process to match, as the two stage desulfurization process of gas desulfurization, reached the purpose very good. In the synthetic ammonia industrial raw material gas production is often used Zinc Oxide and molecular sieve dry desulfurization method as a method for removing organic sulfur and fine desulfurization.

Hot gas desulfurization technology in the development of

Hot gas desulfurization technology in purification temperature greater than 300OThe desulfurization process of C under the condition of complete. Is the main metal oxide desulfurizer chemical removal method. In addition, there are electrochemical membrane separation and selective catalytic oxidation method, the two methods can step into the H2S element of S recovery, eliminating the complex metal oxides desulfurizer regeneration process, investment and operating cost is low, but currently only at the stage of laboratory development, there is a big limitation on the removal of sulfur and precision operating temperature.

Metal oxide desulfurizer removal method is chemical reaction under the condition of high temperature, metal oxide and hydrogen sulfide, chemical reaction, metal sulfide formation, the process of gas phase and removal of hydrogen sulfide. The metal sulfides generated in the oxidizing atmosphere in regeneration, recycling application of desulfurization agent. The mechanism of desulfurization and regeneration following said:

At present, the development of high temperature coal gas desulfurizer mainly concentrated in calcium, iron, zinc, copper oxide and composite oxides. The development process including fixed bed, moving bed, fluidized bed, gas flow bed process.

High temperature purification without reducing the gas temperature to room temperature to purify the gas, can be used for hot gas high temperature sensible thermal conditions, in the coal gasification combined power generation, high temperature desulfurization process without water vapor and carbon dioxide removal to remove wet desulfurization, increase the gas volume driven gas through the flat. These advantages, the research and development of the high temperature purification process has a very attractive prospect. However, the current high temperature gas purification technology mostly in the development stage, small scale experimental study on gas pressure from 0.1-4.8MPa, the gas temperature from 300-600OC, the purification efficiency reached 80-99%. In spite of this, but also improve the stability and high temperature gas purification purification efficiency, such as equipment corrosion, wear and life, desulfurizer recycling low processing efficiency, sulfur and other issues.