CN105417813A - Technique for treating desulfurization waste solution of carbonate under vacuum - Google Patents

Abstract

A technique for treating desulfurization waste solution of carbonate under vacuum comprises the following steps: placing remaining ammonia water and the desulfurization waste solution in a mixer, adding a reaction amount of ammonium sulfate or sulfuric acid in the mixer, and fully mixing uniformly in the mixer; delivering liquid mixed by the mixer to the upper part of a distilling section of an ammonia distillation tower, carrying out steam stripping distillation on the upper part of the ammonia distillation tower, and removing HCN, H2S and NH3 in the liquid; adding alkali liquor in the middle of the ammonia distillation tower and decomposing remaining ammonium sulfate or sulfuric acid; discharging ammonia distillation steam from the top of the ammonia distillation tower and feeding into a follow-up device; and draining distillation waste water from the bottom of the ammonia distillation tower and feeding into the follow-up device. SO4-2 in the ammonium sulfate or sulfuric acid replaces CN- and S-2 in the desulfurization waste solution, steam stripping distillation is carried out to remove cyanide and sulfide in the desulfurization waste solution, so that the cyanide and the sulfide in the waste solution are reduced to be below 50 mg/L, and then the waste solution can be delivered to a biochemical water treatment system; mixed liquor of the desulfurization waste solution, the remaining ammonia water and the small amount of added ammonium sulfate or sulfuric acid enters the ammonia distillation tower; and other devices are not required.

Description

A kind of vacuum carbonate desulfuration waste liquid treatment process method

Technical field

The present invention relates to a kind of vacuum carbonate desulfuration waste liquid treatment process method.

Background technology

Vacuum carbonate (comprising: vacuum potassium carbonate, vacuum sodium carbonate) sulfur method is widely used in coking industry coal gas desulfurization, but inevitably produce waste liquid in desulphurization system, prussiate, sulfide, to ensure that desulphurization system is effectively run, treatedly must be dropped to below 50mg/l and just can deliver to biochemical water treatment system containing prussiate (0.2 ~ 50g/l), sulfide (0.5 ~ 50g/l) in these waste liquids by continuous eliminating waste liquid.

The vacuum carbonate desulfurization waste liquor treatment process that coking industry is not also used widely, implement back at present and convert in coking coal and in waste liquid, add flocculation agent thus produce the method (ZL201010191744.8 precipitated, ZL201310319791.X, ZL201410779950.9), or add the method that oxygenant carries out being oxidized, but all because the intrinsic problem of method is not yet used widely, Chinese invention patent application ZL201510279286.6 discloses to analyse with acidolysis and adds air air lift method, uncertainty may be brought for subsequent disposal containing a large amount of air in the acid gas of resolving.

Summary of the invention

In order to overcome the above-mentioned deficiency of existing vacuum carbonate desulfuration waste liquid treatment process method, the invention provides a kind for the treatment of process method that simply effectively can process vacuum carbonate desulfurization waste liquor.

The technical scheme that the present invention solves its technical problem is: a kind of vacuum carbonate desulfuration waste liquid treatment process method: remained ammonia, desulfurization waste liquor are all placed in a mixing tank, and in mixing tank, add sulphur ammonium or the sulfuric acid of reacting weight, and fully mix in a mixer;

Deliver to the top of the distilling period of ammonia still through the mixed liquid of mixing tank, mixed solution, in the distillation of ammonia still top stripping, removes HCN, the H in liquid ₂s, NH ₃;

Add alkali lye at the middle part of ammonia still, decompose remaining sulphur ammonium or sulfuric acid;

The gas of ammonia still process is discharged from ammonia still top and is sent into follow up device, and distillation waste water is discharged and sent follow up device bottom ammonia still.

Beneficial effect of the present invention is: 1. processing method is by the SO in sulphur ammonium or sulfuric acid ₄ ^-2cN in displacement desulfurization waste liquor ^-and S ^-2and stripping distills and removes prussiate in desulfurization waste liquor, sulfide, makes the prussiate in waste water, sulfide drops to below 50mg/l and reaches the requirement delivering to biochemical water treatment system; 2. desulfurization waste liquor, remained ammonia and a small amount of sulphur ammonium added or sour sulfuric acid, mixed solution enters ammonia still, does not need separately to establish device.

Embodiment

Below in conjunction with embodiment, the present invention is described in further detail.

Embodiment one

A kind of vacuum carbonate desulfuration waste liquid treatment process method: remained ammonia, desulfurization waste liquor are all placed in a mixing tank, and add the sulphur ammonium of reacting weight in mixing tank, and fully mix in a mixer;

Deliver to the top of the distilling period of ammonia still through the mixed liquid of mixing tank, mixed solution, in the distillation of ammonia still top stripping, removes HCN, the H in liquid ₂s, NH ₃, involved reaction is as follows:

（1）K ₂S+（NH ₄） ₂SO ₄→NH ₃↑+H ₂S↑+K ₂SO ₄

（2）KCN+（NH ₄） ₂SO ₄→NH ₃↑+HCN↑+K ₂SO ₄

（3）Na ₂CO ₃+（NH ₄） ₂SO ₄→NH ₃↑+CO ₂↑+H ₂O+K ₂SO ₄；

Add alkali lye at the middle part of ammonia still, decompose remaining sulphur ammonium, involved reaction is as follows: NaOH+(NH ₄) ₂sO ₄→ NH ₃↑+H ₂o+Na ₂sO ₄;

The gas of ammonia still process is discharged from ammonia still top and is sent into follow up device, and distillation waste water is discharged and sent follow up device bottom ammonia still.

Embodiment two

A kind of vacuum carbonate desulfuration waste liquid treatment process method: remained ammonia, desulfurization waste liquor are all placed in a mixing tank, and add the sulfuric acid of reacting weight in mixing tank, and fully mix in a mixer;

Deliver to the top of the distilling period of ammonia still through the mixed liquid of mixing tank, mixed solution, in the distillation of ammonia still top stripping, removes HCN, the H in liquid ₂s, NH ₃, involved reaction is as follows:

（1）K ₂S+H ₂SO ₄→H ₂S↑+K ₂SO ₄

（2）KCN+H ₂SO ₄→HCN↑+K ₂SO ₄

（3）Na ₂CO ₃+H ₂SO ₄→CO ₂↑+H ₂O+K ₂SO ₄；

Add alkali lye at the middle part of ammonia still, decompose remaining sulfuric acid, involved reaction is as follows: NaOH+H ₂sO ₄→ H ₂o+Na ₂sO ₄;

The gas of ammonia still process is discharged from ammonia still top and is sent into follow up device, and distillation waste water is discharged and sent follow up device bottom ammonia still.

Claims (1)

1. a vacuum carbonate desulfuration waste liquid treatment process method, is characterized in that: remained ammonia, desulfurization waste liquor are all placed in a mixing tank, and in mixing tank, add sulphur ammonium or the sulfuric acid of reacting weight, and fully mixes in a mixer;

Deliver to the top of the distilling period of ammonia still through the mixed liquid of mixing tank, mixed solution, in the distillation of ammonia still top stripping, removes HCN, the H in liquid ₂s, NH ₃;

Add alkali lye at the middle part of ammonia still, decompose remaining sulphur ammonium or sulfuric acid;

The gas of ammonia still process is discharged from ammonia still top and is sent into follow up device, and distillation waste water is discharged and sent follow up device bottom ammonia still.