1 Performance features and catalytic oxidation principle
1.1 Performance features
1） The product is suitable for coke oven gases with high/medium/low sulphur content. Fast desulfurization and decyanation speed, high efficiency, desulfurization efficiency is above 98%, and decyanation efficiency is above 90%.
2） It can remove inorganic sulfur and organic sulfur at the same time.
3） Large sulfur foam particle, easy to separate, low dosage, and low cost.
4） Low processing cost and little environmental pollution.
1.2 Reaction principle
1）Absorption reaction
2）Desulphurizing reaction
3） Regeneration reaction
4） side reaction
1.3 Performance index
Appearance: blue black powder, with particle size less than 20 meshes; water insoluble matter (﹪)≦3.00; catalytic activity≧0.06min－1.
2 Application in HPF desulfurization process of coke oven gas
2.1 Technological parameters
List 1 Main technological parameters
|
Item |
Unit |
Basic parameters |
Industrial operating parameters |
|
Liquid-gas ratio |
L/m3 |
12 ～ 30 |
26.8 |
|
Superficial velocity |
m/s |
0.3 ～ 1.2 |
0.57 |
|
Sulfur capacity |
kg/m3 |
0.3 ～ 1.8 |
0.2 ～ 1.6 |
|
Regeneration time |
min |
10 ～ 30 |
20 |
|
Blasting density |
m3/h · m2 |
20 ～ 100 |
100 |
|
Desulfurization temperature |
℃ |
30 ～ 40 |
30 ～ 35 |
|
Dosage of catalyst |
kg/TH2S |
0.6 ～ 0.8 |
0.8 ～ 1.2 |
|
PH value |
|
8.3 ～ 8.8 |
8.3 ～ 8.5 |
|
ZL concentration |
ppm |
30 ～ 50 |
30 ～ 50 |
|
Suspended sulfur |
mg/L |
﹤ 100 |
﹤ 100 |
|
Thiocyanate content |
g/L |
﹤ 150 |
﹤ 150 |
|
H2S removal rate |
﹪ |
95 ～ 98 |
|
|
HCN removal rate |
﹪ |
87 ～ 90 |
|
|
Organic sulfur removal rate |
﹪ |
50 ～ 60 |
|
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2.2 Method of application
2.3 Application result in HPF desulfurization process by ammonia process
Some coke oven gases adopt HPF desulfurization process by ammonia process. The designed gas treatment capacity is 57,000m3/h, H2S content of inlet gas is 5～6g/m3, H2S content after desulfurization≦0.5g/m3.
3 Increase and control of secondary salt
One of the major problems of wet oxidation desulfurization process is growth rate and treatment of waste liquor. HPF desulfurization process can effectively solve the treatment problem of waste liquor without obvious significance on coke quality and gas content.
3.1 Temperature of desulfurizing liquid
Desulfurization and regeneration two processes should be taken into consideration during temperature control. The former is exothermic reaction; lower temperature is good for desulfurization operation and reduces side reaction. Gas temperature is 35℃ and desulfurizing liquid temperature is 38℃.
3.2 Alkalinity of desulfurizing liquid
According to absorption reaction requirement in 1.2.1, ZL desulfurization catalyst must be used in alkaline solutions (ammonia or sodium carbonate).
3.3 Blast intensity
Sufficiently high oxygen density is essential to ZL catalyst regeneration. Blast intensity is according to actual regeneration effect of desulfurizing liquid.
Most notably, side reaction in 1.2.4 is related to HCN content in gas and separation situation of elemental sulfur.
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4 Conclusion
ZL desulfurization catalyst has favorable performance features and it can be used in wet oxidation desulfurization process of coke oven gas. In HPF desulfurization process by ammonia process, indicators of ZL desulfurization catalyst can meet design requirements. It has features such as high sulphur removal efficiency, large sulfur particle, easy to separate, low operating cost, and etc.
