System and method for reducing ammonia nitrogen content

Abstract

The invention relates to the technical field of coal gasification and gas shift, and discloses a system and method for reducing the ammonia nitrogen content. The system comprises a high-temperature condensate treatment device and a low-temperature condensate treatment device, wherein the high-temperature condensate treatment device is used for conducting stripping on an input high-temperature shift condensate by using input high-pressure flash steam to generate a high-temperature condensate with the ammonia content meeting conditions, conducting gas-liquid separation on stripping steam generated after stripping and outputting a gas product and a liquid product to the low-temperature condensate treatment device; the low-temperature condensate treatment device is used for conducting stripping on the liquid product and an input low-temperature shift condensate by using input low-pressure steam and the gas product to generate a low-temperature condensate with the ammonia content meeting conditions, and conducting gas-liquid separation on stripping steam generated after stripping to generate an ammonia-containing condensate and flash non-condensable gas. By means of the system, the content of ammonia nitrogen in black water and grey water in a gasification process unit can be reduced, and the content of the ammonia nitrogen in the grey water discharged by the gasification process unit can be reduced to the degree that wastewater is well accepted.

Description

technical field [0001] The invention relates to the technical field of coal gasification and gas conversion, in particular to a system for reducing ammonia nitrogen content and a method for reducing ammonia nitrogen content. Background technique [0002] The coal water slurry gasification process is based on the partial oxidation reaction of coal water slurry and high pressure oxygen through high temperature and high pressure, and the reaction products are crude gas and liquid slag. The gasification product enters the water bath of the quench chamber with a certain water level through the downcomer, and the slag solidifies in the water bath and sinks to the bottom of the gasifier equipment, and is regularly discharged through the lock hopper. Crude gas is mainly composed of carbon monoxide, carbon dioxide, and hydrogen, and there are also some impurities such as ammonia nitrogen. The crude gas escapes and rises to the gas outlet located on the upper part of the quenching ch...

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Problems solved by technology

[0008] There are many patented technologies reported now, and these patents only deal with the stripping of the shifted low-temperature condensate (mainly the washing water of the shifted gas scrubbing tower), and do not deal with the high-temperature shifted condensate that accounts for a large proportion of the shift. , so the problem of high ammonia nitrogen content in the black water and gray water of the gasification process unit has not been solved well

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