A process and device for producing concentrated ammonia water by negative pressure operation

Abstract

The invention discloses a process and a device for producing strong ammonia water through negative pressure operation, and belongs to a coking chemical product recovery technology. Ammonia steam from an ammonia steaming tower dephlegmator is cooled by a condenser to be partially condensed, condensed liquid is discharged to the bottom of an ammonia recovering tower through the gravity action, and the non-condensed ammonia steam and noncondensable gas are pumped by a dry vacuum pump to generate negative pressure; the gas phase pumped through the dry vacuum pump is heated and pressurized to enter the ammonia recovering tower, ammonia removal is conducted by circulating ammonia water cooled externally, and the recovery rate of the ammonia is 90 to 95 percent; the noncondensable gas at the top of the ammonia recovering tower and containing a small amount of ammonia is directly discharged into a gas pipeline in front of an ammonia absorbing device or an ammonia process oxidation desulfurization device, and a strong ammonia water product with the mass concentration being 15 to 25 percent is obtained at the bottom of the tower; the process can meet negative pressure ammonia steaming operation with various vacuum degrees, and has the advantages of small equipment investment, low energy consumption, simple flow, low operation cost, no environmental pollution and the like.

Description

technical field [0001] The invention relates to the technical field of recovery of coking chemical products, in particular to a process and a device for producing concentrated ammonia water by negative pressure operation. Background technique [0002] The residual ammonia water distillation process in the coking industry is used to distill ammonia, hydrogen sulfide, carbon dioxide, hydrogen cyanide and other impurities in the raw ammonia water to obtain high-concentration ammonia vapor or concentrated ammonia water. [0003] At present, the ammonia distillation process of coking residual ammonia water is divided into two processes: positive pressure ammonia distillation and negative pressure ammonia distillation; the ammonia vapor at the top of the positive pressure ammonia distillation process can be directly cooled to obtain concentrated ammonia water. The ammonia vapor from the top of the negative pressure ammonia distillation process will be partially condensed after coo...

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Problems solved by technology

[0006] The negative pressure ammonia steaming device whose patent authorization announcement number is CN 203768044 U uses a vacuum jet pump to suck non-condensable gas to generate negative pressure, and utilizes circulating ammonia water to absorb ammonia in the non-condensable gas in the vacuum jet pump to recover to obtain a certain concentration. ammonia water, but the vacuum jet pump needs to circulate a large amount of ammonia water and consume more mechanical energy to obtain a certain degree of vacuum, and the degree of negative pressure generated by the vacuum jet pump is relatively limited, and the low degree of vacuum makes the temperature at the bottom of the ammonia distillation tower relatively high High, which limits the application of negative pressure ammonia distillation in the utilization of low-grade heat energy, which is not conducive to energy-saving operation

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