Energy-saving tail gas deamination process and equipment for production of sodium cyanide

Abstract

Belonging to the technical field of energy conservation and environmental protection, the invention particularly relates to an energy-saving tail gas deamination process and equipment for production of sodium cyanide. Specifically, high-temperature softened water coming out of a cracking furnace serves as a heat source of a lithium bromide unit and returns to a softened water pool after being cooled so as to get ready for entering the cracking furnace again; tail gas enters the lower part of an ammonia absorption tower, spray water enters the upper part of the ammonia absorption tower for spray deamination on the tail gas, the generated dilute ammonia water is sent into a kettle liquid heat exchanger through a dilute ammonia water pump, and then enters a distillation tower, part of the kettle liquid subjected to distillation deamination by the distillation tower undergoes heat exchange by the kettle liquid heat exchanger, and is sent as spray water by a spray water pump to two circulating water plate heat exchangers for primary cooling by cooling water, after coming out of the circulating water plate heat exchangers, the spray water enters two cold water plate heat exchangers for secondary cooling through cold water generated by the lithium bromide unit, and then the spray water returns to the ammonia absorption tower again to spray the tail gas. Through the recycling, the ammonia content of the tail gas can reach the production requirement of 0.8% or below.

Description

technical field [0001] The invention belongs to the technical field of energy saving and environmental protection, and in particular relates to an energy-saving tail gas deamination process and equipment for producing sodium cyanide. Background technique [0002] In the production process of sodium cyanide, ammonia and pentane are cracked into hydrogen cyanide gas at high temperature in the cracking furnace. In order to ensure that the subsequent process will not be affected by high-temperature gas, demineralized water is circulated in the upper gas chamber of the cracking furnace to cool down the furnace gas. A large amount of hot water is generated here, and it is necessary to use a cooling tower to continuously cool down the softened water. [0003] After filtration, use sodium hydroxide solution to absorb the reaction to generate sodium cyanide solution. The tail gas after the absorption process contains unreacted ammonia, and the direct discharge to the atmosphere is v...

AI Technical Summary

Problems solved by technology

[0004] 1) Cooling the softened water through the cooling tower will waste the heat source of the softened water, and the operation of the cooling tower will increase the cost

[0005] 2) Since the spray water is recycled and heated by steam, the temperature of the spray water is as high as 85°C, resulting in a decrease in the solubility of ammonia

In order to effectively absorb the ammonia in the tail gas, it is necessary to use a large amount of spray water, the concentration of the obtained ammonia water is reduced, and it is necessary to use a larger amount of steam for distillation, resulting in waste of water resources and energy

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