Desulfurization of transformed gas

Features of the 888 desulfurization method: 1. Strong ability to remove high levels of sulfur. When the H2S content in coke oven gas is above 4 g/nm3, the process requirements can be met after desulfurization; when the H2S content in shift gas is as high as 3.5 g/nm3 or more, the concentration at the outlet can be reduced to below 50 mg/nm3. 2. Comprehensive desulfurization. It can remove both inorganic sulfur and a certain amount of organic sulfur, with the maximum removal rate of organic sulfur exceeding 80%. Under the same operating conditions, switching to the 888 desulfurization catalyst can increase the capacity of the desulfurization unit by more than 20%. 3. Prevent sulfur buildup that can clog the tower. During regeneration, the sulfur particles floated out are large, the solution viscosity is low, and the sulfur particles are easy to separate ； The 888 desulfurization fluid has a strong self-cleaning ability, providing tower cleaning while carrying out desulfurization. 4. Low cost. Under the same loading conditions, replacing other catalysts with the “888 desulfurization catalyst” resulted in a significant reduction in desulfurization costs. During the production process, side reactions can be effectively suppressed, thereby reducing the formation of by-products and **decreasing the frequency of emissions and the need to replace solutions. 5. The “888 desulfurization catalyst” does not require any additional catalysts; its pre-activation process is simple and quick. It maintains a stable desulfurization efficiency whether ammonia water or soda ash is used as the absorbent. 6. The desulfurization lean solution using the “888” method has a low suspended sulfur content. It can generally be reduced to below 0.3 g/L; a clear solution helps to lower the resistance in the desulfurization system. If the desulfurization catalyst used in other wet oxidation methods has a high content of suspended sulfur, switching to the \"888 desulfurization catalyst\" can lead to a rapid reduction in this value. 7. The “888” desulfurization fluid exhibits good selectivity for H2S; even when the ratio of CO2 to H2S in the gas is high, it can still effectively remove H2S to the specified control levels. 8. The side reaction rate during the desulfurization process is low, resulting in low absorbent consumption ； The sulfur recovery rate is high, and the purity of the by-produced sulfur is also high. 9. Under the action of the “888 desulfurization catalyst”, polysulfidation reactions occur, and sulfur is precipitated during catalytic oxidation; it is then separated out during regeneration, thereby preventing and eliminating sulfur accumulation that can block pipes and equipment packing. 10. The desulfurization catalyst has high activity, requires a low dosage, is cost-effective to operate, and is easy to use. When switching to the \"888 desulfurization catalyst\" for desulfurization in old systems, there is no need to shut down the operation or discharge the existing desulfurization liquid, thereby reducing environmental pollution.

A desulfurization solution is prepared by adding sodium metavanadate, tannic acid oxide, 888, etc. to a dilute Na2CO3 alkaline solution; this solution comes into countercurrent contact with the semi-water gas that needs to be purified in a packed tower to remove H2S. The desulfurization solution that has absorbed H2S is regenerated in a regeneration tank through oxidation with air under the catalytic action of 888, thereby regenerating the solution and allowing elemental sulfur to be separated out. The solution is recycled. The absorption and regeneration reactions take place in four steps: 1. Alkaline solution absorbs H2S to form HS-Na2CO3; H2S + Na2CO3 = NaHS + NaHCO3. 2. NaHS reacts with sodium metavanadate (NaVO3) to produce sodium metavanadate octoxide, with elemental sulfur being precipitated: 2NaHS + 4NaVO3 + H2O = Na2V4O9 + 4NaOH + 2S↓. 3. Sodium metavanadate octoxide is oxidized by tannin (Q represents tannin): Na2V4O9 + Q (oxidized state) + 2NaOH + H2O = NaVO3 + Q (reduced state). 4. The reduced-state tannin is oxidized to its oxidized state by air under the catalysis of 888: 888 (Qn) + O2 = 888 (Q)n + 2. Major side reactions include: 1. Na2CO3 + CO2 + H2O = 2NaHCO3. 2. 2NaHS + O2 = Na2S2O3 + H2O. 3. 2NaHS + 2HCN + O2 = 2NaCN + 2H2O. 4. NaCNS + 5O2 = Na2SO4 + CO2 + SO2 + N2

This post was last edited by Chemical Gas Purification on 2010-9-18 at 21:37. Isn’t too much catalyst being used? With our SDS high-efficiency catalyst, only soda ash and SDS are required; the principle is similar to what was mentioned in the second comment. Additionally, we use a filler-free stripping tower, and for technical inquiries, please contact liutaoandzdy@sina.com

This post was last edited by Wandering D Scorpion on 2010-9-19 23:30. 1. Principle of tannin desulfurization: The tannin desulfurization solution comes into countercurrent contact with the reformate gas in the desulfurization tower to remove H2S from the gas; the desulfurized solution is then oxidized and regenerated in a regeneration tank. The reactions are as follows: (1) Absorption reaction: Na2CO3 + H2S = NaHS + NaHCO3; (2) Sulfur precipitation reaction: 2NaHS + 4NaVO3 + H2O = Na2V4O9 + 4NaOH + 2S↓; (3) Regeneration reaction: Na2V4O9 + 2TEOS (quinone-type tannin) + 2NaOH + H2O = 4NaVO3 + 2TEYS (phenol-type tannin); (4) Oxidation reaction: 2TEYS (phenol-type tannin) + O2 = 2TEOS (quinone-type tannin) + H2O; NaHCO3 + NaOH = Na2CO3 + H2O; (5) Overall reaction equation: 2H2S + O2 = 2S↓ + 2H2O; (6) Major side reactions: 2NaHS + 2O2 = Na2S2O3 + H2O; 2Na2S2O3 + O2 = 2Na2SO4 + 2S↓. 2. Principle of sulfur recovery: When heated, the bubbles burst, and the elemental sulfur particles begin to aggregate, grow larger, and sink, thereby separating the sulfur foam from the solution. When the sulfur particles are further heated to their melting point, liquid sulfur is formed.