Method for reducing content of ammonia nitrogen in urea process condensate

Abstract

The invention discloses a method for reducing the content of ammonia nitrogen in urea process condensate. The method comprises the following steps: (1) introducing urea process condensate into a hydrolyzer for urea hydrolysis; (2) allowing a liquid phase obtained after urea hydrolysis to enter into an equilibrium distillation device through an outlet pipe of the hydrolyzer for equilibrium distillation; and (3) allowing a gas phase produced after equilibrium distillation to enter into an upper tower of a desorber or to be mixed with a gas phase product at the tower top of the desorber, allowing a liquid phase produced after equilibrium distillation to enter into the top of a lower tower of the desorber and carrying out gas stripping on the liquid phase so as to reduce the content of ammonia nitrogen in the urea process condensate. With the method provided by the invention, the concentration of ammonia nitrogen in a feed at a lower segment of the desorber can be regulated and controlled, the usage amount of low pressure steam LPS at tower bottom of the desorber and high pressure steam HPS in the hydrolyzer can be reduced, and thus, the usage amount of steam is reduced in two ways, the concentration of ammonia in water at tower bottom is stabilized, and water yield at the tower bottom is reduced.

Description

technical field [0001] The invention relates to a method for reducing ammonia nitrogen content in urea process condensate, and belongs to the technical field of waste water recovery and utilization in the urea process. Background technique [0002] The urea process condensate containing ammonia, carbon dioxide and urea produced in the urea production process must be treated to meet environmental protection requirements and effective use of resources. At present, for the purification of urea process condensate, urea production enterprises at home and abroad generally adopt the method of combining hydrolysis and desorption, and research and develop a variety of different urea process condensate treatment processes, among which the urea hydrolysis-desorption technology of Snamprogetti Company is the industry It is a relatively mature process in production and application, and it is the most widely used process in China. The process includes three consecutive treatment stages, ...

AI Technical Summary

Problems solved by technology

On the one hand, in order to meet the quality requirements of urea hydrolysis, it is necessary to increase the amount of high-pressure steam; on the other hand, in order to meet the requirement that the ammonia content in the water quality is less than 3ppm, the lower tower of the desorption tower needs to increase the amount of low-pressure steam. increase

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