Vacuum carbonate multistage-circulation step-by-step desulfurization process and device thereof

Abstract

The invention discloses a novel vacuum carbonate multistage-circulation step-by-step desulfurization process. The vacuum carbonate multistage-circulation step-by-step desulfurization process disclosed by the invention comprises the steps of adopting multistage graded deep desulfurization, partly back flowing and partly regenerating desulfurization solution, partly back flowing regenerated desulfurization solution and the like. The H2S content in coal gas after desulfurization is decreased to 50 mg / nm<3>; the problem that the desulfurization efficiency of the existing vacuum carbonate (potassium carbonate and sodium carbonate) desulfurization process is low (the H2S content is generally 200-500 mg / nm<3>) is avoided; and furthermore, the problems that sulfion and total cyanide in wastewater are seriously exceeded due to the fact that a lot of S-2 and CN-1 in alkali wash water are brought into a sewage treatment system through distilled ammonia wastewater are avoided.

Description

technical field [0001] The invention relates to a vacuum carbonate desulfurization process and a device for realizing the process. Background technique [0002] Coke oven gas contains hydrogen sulfide, which varies according to the sulfur content of coking coal. Generally, the hydrogen sulfide content is 3-12g / nm 3 (nm 3 - Refers to cubic meters of gas per standard working condition), usually 6 ~ 8g / nm 3 Scope, according to the current national standard on the emission of sulfur dioxide in flue gas after gas combustion, the hydrogen sulfide in the gas should be controlled at less than 50-100 mg / nm 3 (It depends on different regions). The currently applied vacuum carbonate (vacuum potassium carbonate or vacuum sodium carbonate) desulfurization process adopts a single-stage desulfurization-regeneration process. After desulfurization by this process, the hydrogen sulfide content in the gas is between 350 and 500mg / nm 3 Between, can not meet the requirements of the current n...

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Problems solved by technology

[0002] Coke oven gas contains hydrogen sulfide, which varies according to the sulfur content of coking coal. Generally, the hydrogen sulfide content is 3-12g / nm 3 (nm 3 - Refers to cubic meters of gas per standard working condition), usually 6 ~ 8g / nm 3 Scope, according to the current national standard on the emission of sulfur dioxide in the flue gas after gas combustion, the hydrogen sulfide in the gas should be controlled at less than 50-100 mg / nm 3 (It depends on different regions). The currently applied vacuum carbonate (vacuum potassium carbonate or vacuum sodium carbonate) desulfurization process adopts a single-stage desulfurization-regeneration process. After desulfurization by this process, the hydrogen sulfide content in the gas is between 350 and 500mg / nm 3 Between, can not meet the requirements of the current national standard; some users increase the alkali washing section (ie: sodium hydroxide washing section), although this can reduce the hydrogen sulfide in the gas to 200mg / nm 3 However, the sulfur ions and cyanide ions in the lye enter the wastewater treatment system through the ammonia distillation wastewater with the lye, and the wastewater treatment system cannot handle such a large amount of sulfide ions and cyanide ions, so that the total cyanide and sulfide ions in the water treatment drainage seriously exceed the standard and cannot qualified

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