Process for purifying coke oven gas and recycling high-quality stronger ammonia water and sulfur

Abstract

The invention relates to a process for purifying coke oven gas and recycling high-quality stronger ammonia water and sulfur, which comprises the following steps: coke oven gas enters a desulfurization tower to remove hydrogen sulfide, hydrogen cyanide and part of ammonia in coal gas, and then enters an ammonia absorption tower to remove most of ammonia in the coal gas; the ammonia absorption pregnant solution enters a desorption tower to be regenerated, and 10-25% of high-quality stronger ammonia water can be recycled through the process. Compared with the prior art, the process has the advantages that hydrogen sulfide and ammonia in the coke oven gas are utilized most effectively, the concentration of the recovered high-quality stronger ammonia water is adjustable, and the recovered high-quality stronger ammonia water can be directly used for desulfurization and denitrification or preparation of anhydrous ammonia products; the content of hydrogen sulfide in the purified gas is not more than 200mg / m < 3 >, the content of ammonia is not more than 50mg / m < 3 >, and the content of total ammonia in the ammonia distillation wastewater is not more than 150mg / L; the whole process has the characteristics of high deacidification and deamination efficiency, high resource utilization rate, reduced process equipment material grade, low engineering investment, low energy consumption and the like.

Description

technical field [0001] The invention relates to a new process for desulfurization, deamination and decyanation of gas, belonging to chemical engineering technology, in particular to a process for recovering high-quality concentrated ammonia and sulfur by purifying and recycling coke oven gas. Background technique [0002] At present, most domestic gas desulfurization processes adopt wet oxidation desulfurization and wet absorption desulfurization. Among them, the more popular wet oxidation methods include HPF desulfurization with ammonia as an alkali source, and the more popular wet absorption methods include ammonia sulfur cyclic desulfurization. (AS) and vacuum carbonate desulfurization. However, these running processes have their own advantages and disadvantages. Among them, HPF desulfurization effect is better, but desulfurization waste liquid and low-quality sulfur paste are difficult to handle. The vacuum carbonate method also has the problem that the desulfurization ...

AI Technical Summary

Problems solved by technology

However, these operating processes have their own advantages and disadvantages. Among them, HPF has better desulfurization effect, but desulfurization waste liquid and low-quality sulfur paste are difficult to deal with

The vacuum carbonate method also has the problem of difficult treatment of desulfurization waste liquid

Although the AS process does not have the problem of solid waste and liquid waste, the desulfurized gas contains more than 500 mg / m of hydrogen sulfide 3 , does not meet the requirements of coking indicators, and this process has problems such as high equipment investment, high operation technology requirements, easy blockage and corrosion of equipment

[0003] Some domestic scholars and engineers and technicians have made some improvements to the existing AS process. Chinese patent CN201611249990.8 disclosed a coke oven gas desulfurization and deammoniation process for ammonia production on May 17, 2017. On the basis of this, the desulfurization rich liquid desorption tower is pressurized to improve the desulfurization efficiency, and ammonia water is prepared by deacidifying and distilling the remaining ammonia water under low pressure, but there are still problems that need to be improved in the whole process. The lower part of the tower will increase the pH of the ammonia washing water sent to the ammonia washing from the desorption tower, which will affect the deammonization effect of the gas. , most of the acid gas still enters the side line ammonia gas, which affects the purity of ammonia gas. When it is sent to flue gas desulfurization and denitrification, the color of ammonium sulfate mother liquor will become darker and precipitate will be formed.

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