Method for reusing desulfurization and denitration by-products

A by-product, denitration technology, applied in chemical instruments and methods, preparation of alkali metal sulfites, ammonia compounds, etc., can solve the pollution of boiler exhaust emissions, reduce the use of non-renewable resources, sulfate and sulfite problems such as low impurity content, to achieve the effect of obvious social and environmental benefits, significant economic benefits, and increased benefits

Inactive Publication Date: 2016-05-04
SHAOXING UNIV YUANPEI COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The sulfate and sulfite prepared by this method have low impurity content, good color of the finished product, and no need to burn or heat sulfur ore, which reduces the use of non-renewable resources. At the same time, due to the use of waste resources, the price of the finished product is low. Market competition The advantages are obvious, and in the end, the problem of environmental pollution caused by boiler exhaust emissions is also largely solved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Example 1: According to the present invention, SO is directly generated 2 and ammonium sulfate

[0032] Reaction principle: (NH 4 ) 2 SO 3 +H 2 SO 4 ==(NH 4 ) 2 SO 4 +H 2 O+SO 2 ↑

[0033] When ammonia water is used to absorb sulfur oxides and nitrogen oxides produced in the coal combustion process, stop feeding oxygen, then concentrate the main product of ammonium sulfite slurry in the circulation tank, and slowly feed concentrated sulfuric acid until no gas is generated. The produced gas SO 2 Then it is absorbed by water, and then a second-stage exhaust gas absorption device is added later. The first-stage exhaust gas can be recycled to the upper-stage SO 2 Absorption tank, adding starch I to the second-stage exhaust gas absorption device 2 The solution is used to monitor the degree of (absorption) reaction in the previous stage, and finally the concentration of sulfurous acid formed by the reaction in the solution is determined by iodometric method. T...

Embodiment 2

[0034] Example 2 : directly generate sodium sulfite and ammonium sulfate according to the present invention

[0035] Reaction principle: (NH 4 ) 2 SO 3 +H 2 SO 4 ==(NH 4 ) 2 SO 4 +H 2 O+SO 2 ↑

[0036] SO 2 +2NaOH=Na 2 SO 3 +H 2 o

[0037] Generate SO 2 The method is with embodiment 1, and soda ash is made into the lye of certain concentration, reacts with sulfur dioxide gas and obtains sodium sulfite solution. The sodium sulfite solution enters the concentrator, and a double-effect continuous concentration process is adopted. The water was distilled off to obtain a suspension containing crystals of sodium sulfite. Put the qualified material of the concentrator into the centrifuge to realize solid-liquid separation, and the solid (wet sodium sulfite) enters the airflow dryer, and is dried by hot air to obtain the finished product. The mother liquor is returned to the alkali distribution tank for recycling. The ammonium sulfate mother liquor that generates ...

Embodiment 3

[0038] Example 3 : directly generate calcium sulfite and ammonium sulfate according to the present invention

[0039] Reaction principle: (NH 4 ) 2 SO 3 +H 2 SO 4 ==(NH 4 ) 2 SO 4 +H 2 O+SO 2 ↑

[0040] SO 2 +Ca(OH) 2 =CaSO 3 +H 2 o

[0041] Calcium sulfite (CaSO 3 ) is a kind of sulfite, which is used to make calcium-plastic materials, and is also used as a bleaching and dechlorinating agent for cellulose products, a food preservative, and a fermentation bactericide, etc. It has a wide range of uses in industrial production. Generate SO 2 The method is with embodiment 1, calcium hydroxide is made into the lye of certain concentration, reacts with sulfur dioxide gas and obtains calcium sulfite solution. Other processes are similar to the production of sodium sulfite.

[0042] The products such as sulfurous acid, sulfite and ammonium sulfate produced by the invention have high purity and less impurity content, and have remarkable economic and social benefits...

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PUM

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Abstract

The invention relates to a method for reusing desulfurization and denitration by-products. The invention comprises the following steps: (1) in an ammonia process of desulfurization and denitration, stopping adding oxygen (or air) to enable the most by-products to be converted into sulfite and nitrite; (2) continuously adding concentrated sulfuric acid into sulfite and nitrite produced in the reaction above to generate sulfur dioxide, nitrogen, ammonium sulfate, and the like; (3) absorbing the mixed gas generated above through water, sodium hydroxide, sodium carbonate, and the like to product sulfurous acid or sulfite, or adding a catalytic oxidation process for producing sulfurous acid or sulfite; and (4) performing centrifugal separation and drying on ammonium sulfate containing a certain ash content, wherein ammonium sulfate is the main component in the reaction substrate left in the step (2), to obtain an ammonium sulfate product with extremely high purity. The produced products, such as sulfurous acid, sulfite, and ammonium sulfate, have high purity, less impurity contents, and remarkable economic and social benefit.

Description

technical field [0001] The invention relates to a method for comprehensive utilization of desulfurization and denitrification by-products. Background technique [0002] Flue gas, especially coal-fired boiler flue gas, steelmaking flue gas, and thermal power generation, is one of the most important sources of air pollution and has become an important object of environmental governance. At present, China's annual SO emissions from flue gas into the atmosphere 2 The total amount is about 20 million tons. This should be a sulfur resource with great value, but it has become a pollution source with great environmental hazards. In the existing flue gas desulfurization and denitrification purification technologies, such as ammonia desulfurization, the by-products such as ammonium sulfate, sulfuric acid, sulfur dioxide, ammonium sulfite and some nitrogen oxides can partially realize the recycling of sulfur resources during desulfurization. It does not produce secondary pollution an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C1/24C01B17/48C01D5/14C01F11/48
CPCC01C1/246C01B17/48C01D5/14C01F11/48C01P2006/80
Inventor 罗洁
Owner SHAOXING UNIV YUANPEI COLLEGE
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