Method for preparing gypsum by removing boiler flue gas sulphur dioxide with white slime from ammonia alkali factory

A technology of sulfur dioxide and boiler flue gas, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems such as the useless value of calcium sulfite, complicated preparation process of desulfurizer, and many equipment, etc., to achieve broad commercial utilization prospects and achieve clean The effect of low production and investment

Active Publication Date: 2009-01-14
GUANGDONG NANFANG SODA ASH IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The desulfurizer uses natural drying or oven-dried waste alkali slag, which is crushed and sieved to make the particle size less than 44um. The preparation process of the desulfurizer is more complicated
In general, in order to achieve a higher desulfurization rate, this method combines the characteristics of wet and semi-dry desulfurization processes, but also has the disadvantages of long process, many equipment, high investment, and large land occupation.
The product generated after desulfurization by this method is calcium sulfite, and calcium sulfite has no utilization value

Method used

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  • Method for preparing gypsum by removing boiler flue gas sulphur dioxide with white slime from ammonia alkali factory

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Three 65t / h coal-fired boilers in an alkali plant, the sulfur content of the coal is 1.2%, and the flue gas volume is 3×85000Nm 3 / h, the sulfur dioxide content is 2160mg / Nm 3 , The white mud composition of the alkali plant is shown in Table 1:

[0049] Table 1 White mud composition analysis table

[0050] CaO

MgO

SiO 2

Al 2 O 3

Fe 2 O 3

Na 2 O

K 2 O

P 2 O 5

Cl -

S

Loss

40.18

3.56

2.75

1.98

0.63

1.04

0.057

0.080

3.50

4.18

37.13

[0051] Note: In the table, the calcium carbonate in the white mud is all converted to calcium oxide.

[0052] The dust-removed flue gas discharged from the three boilers is sent to a spray tower by a booster fan. The inlet flue gas temperature is 130℃, and the flue gas flow rate in the spray tower is controlled at 3.5-3.8m / s. Use this alkali plant The white mud is prepared into a white mud slurry with a water co...

Embodiment 2

[0056] Two 410t / h coal-fired boilers in a coal-fired power plant, the sulfur content of the coal is 1.5%, and the flue gas volume is 2×55000Nm 3 / h, the sulfur dioxide content is 2860mg / Nm 3 . The dust-removed flue gas discharged from each boiler is sent to two spray towers through two booster fans. The inlet flue gas temperature is 145℃, the flue gas flow rate in the spray tower is controlled at 3.8m / s, and the water content is The white mud slurry with a concentration of 80% is pumped into the absorption zone of the spray tower, and is sprayed in the spray zone cyclically, and contacts and reacts with the flue gas, and the sulfur dioxide in the flue gas is removed. The liquid-gas ratio of the spray tower is 12l / Nm 3 , Control the pH value of the oxidation crystallization pool to 5.8. After desulfurization, the flue gas is discharged from the chimney after the mist eliminator on the upper part of the spray tower. The desulfurization liquid after contact with the flue gas is oxidi...

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Abstract

The invention discloses a method for removing sulfur dioxide in fumes with the by-product of gypsum produced by white mud in the ammonia-soda factory. With such method adopted, the efficiency of removing the sulfur dioxide is more than 95 percent, the purity of the by-product of the gypsum is more than 85 percent, and the water content of the gypsum is less than 4 percent. The method is realized by the following technical proposal: white mud slurry is used as an absorbent for removing the sulfur dioxide; in the spray tower absorbing zone, the white mud slurry reacts with the sulfur dioxide to generate calcium sulfite and calcium bisulfite; the calcium sulfite and the calcium bisulfite are catalyzed and oxidized into calcium sulfate in the oxide crystallization pool; the calcium sulfate is crystallized into gypsum; and gypsum slurry is concentrated, washed and dehydrated, and dried, and then changed into the finished product of gypsum. The method for removing the sulfur dioxide in fumes, which uses waste to restrict waste, not only realizes clean production and circular economy in the ammonia-soda industry, but also provides a more economical sulfur dioxide removing method for surrounding power plants in the ammonia-soda industry, thereby realizing bidirectional treatment of the waste. Furthermore, the by-product of the gypsum has wide commercial prospect after dried.

Description

Technical field [0001] The invention relates to the field of air pollution control and solid waste resource treatment, in particular to a method for removing sulfur dioxide from boiler flue gas by using ammonia-alkali plant white mud and preparing gypsum. Background technique [0002] A large amount of white mud is produced in the production process of soda ash by ammonia-soda method. White mud is a large amount of waste liquid produced in the process of ammonia-soda soda production. Has CaCO 3 , CaSO 4 , Mg(OH) 2 And CaCl 2 At the same time, it also contains CaO. The white mud has a strong alkalinity and a very large amount. It accumulates on the land to form a "white ridge", which not only takes up valuable land resources, but also causes damage to surrounding plants, etc., and harmful substances penetrate into the groundwater , It will pollute nearby water resources. There are many technologies for comprehensive utilization of white mud, but not many of them can adapt to the c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46
Inventor 黄志红何思立张绍训周少奇曾松峰
Owner GUANGDONG NANFANG SODA ASH IND
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