Catalytic Hydrolysis And Absorption Performance In Coke Oven Gas Desulfurization Process

The efficient removal of inorganic sulfide and organic sulfide in coke oven gas is of great significance to improve gas quality,reduce equipment corrosion,reduce environmental pollution and improve the quality of downstream products,which has become a major issue of concern in the coking industry.Hydrogen sulfide(H2S)removal technology is relatively mature,and a variety of wet processes have mature applications in China,especially the technology of alcohol amine has obvious advantages,but there is still much room for further energy saving and improving the separation selectivity of acid gases.Compared with H2S,carbonyl sulfide(COS)is more difficult to remove because of its low acidity and relatively stable chemical properties.Catalytic hydrolysis technology can be coupled with the existing gas desulfurization and decarbonization process,but there are still many difficulties in low temperature catalysis and efficient hydrolysis for COS.In this thesis,the existing technologies of catalytic hydrolysis and aqueous amine absorption were integrated and coupled,and an integrated removal approach of COS and H2S in coke oven gas was innovatively proposed.Through the selection and optimization of low-temperature hydrolysis catalyst and absorbent,the efficient removal of sulfide in coke oven gas was achieved.A low temperature hydrolysis catalyst was prepared by using activated alumina as carrier,and K2CO3,Ba(OH)2,nano-ZnO and nano-NiO as active components.An experimental platform for COS catalytic hydrolysis was constructed.The hydrolysis efficiency of COS was measured under series of catalyst compositions,gas compositions and temperatures.The influence of water vapor,H2S and CO2 contents on COS hydrolysis was explored,and the mechanism of active components and catalytic hydrolysis was clarified.On this basis,the catalyst composition and operating conditions were optimized.When the hydrolysis temperature was 70? and the relative humidity was 60%,the hydrolysis efficiency of COS can reach 92%.Glycine ionic liquid and arginine ionic liquid promoted N-methyldiethanolamine(MDEA)absorbents were constructed.The key thermodynamic parameters such as viscosity,absorption capacity and absorption selectivity were measured,and the effects of absorbent concentration,temperature and partial pressure were clarified.The apparent absorption rate of H2S/CO2 was determined,and the competitive influence mechanism of absorbent concentration and viscosity on absorption rate was clarified.The removal efficiency of H2S and CO2 by the proposed absorbents was verified in a tray column,and the result was better than that of the traditional absorbent under commercial operation.For the arginine ionic liquid promoted MDEA absorbent,the absorption selectivity and desulfurization efficiency in the tower respectively achieved 100%and 2.17,and the overall gas-phase volumetric mass transfer coefficient reached 0.5167 Kmol·m-3·h-1·Kpa-1.The effects of absorbent composition,gas flow rate,liquid flow rate and plate number on the absorption selectivity,removal efficiency and overall volumetric mass transfer coefficient of H2S and CO2 were investigated.In summary,COS hydrolysis catalyst and H2S absorbent were developed in this thesis and through technology integration and innovation,an integrated removal system of COS and H2S in coke oven gas was constructed,and the actual removal efficiency was verified.The results showed that COS can be efficiently hydrolyzed at low temperature,and the water-lean degree of the proposed absorbents(>55wt%)was significantly higher than that of traditional absorbents such as ethanolamine(MEA,<30wt%).Therefore,the integrated removal route proposed in this thesis is of great significance to improve the efficiency of gas desulfurization and energy saving in coking industry,and has a good application prospect.