Study On Potassium Catalyst Recovery Of Coal-Steam Catalytic Gasification

The effect of catalyst loading and temperature on the coal-steam gasification were studied in this article.15% catalyst loading and 700℃were found to be suitable for the satis-factory conversion rate. It was found the catalyst wouldn't loss during the process of gasification, and the presence form of catalyst after gasification are mainly KOH and K2CO3. KAlSiO4 was found through the analysis of XRD, which indicated the catalyst was partly inactivated during the gasification.The catalyst could be recoveried through two ways like water washing and lime digesting. Several factors such as the sensitivity of catalyst solutions to air, the removal of silicon by CO2 treatment, digestion process variables, and water wash process variables, were studied in this article. The optimal operating conditions of water washing were under the atmosphere of N2,300r/min stiring rate,2MPa,150℃, water/residue=16:1, washing 3 times, and the recovery yield of potassium could reach to about 80%. The optimal operating conditions of lime digestion were under the atmosphere of N2,300r/min stiring rate,2MPa, 150℃, water/residue=16:1, CaO/residue=1:2, and the recovery yield of potassium could reach to 90% or more.The sulfide from residue or would be oxidated into sulfate, which was harmful for catalyst recycling, and the atmosphere of N2 can avoid this situation. The componant of sulfide and silicide can be removed by CO2 and the effective recovery yield of potassium will be improved. The catalysic effect of the recovrey catalyst was studied and was found no difference compared to the catalysic effect of fresh catalyst.The mixture of K2O,SiO2 and Al2O3 were calcined in the muffle furnace, which was taken to simulate the environment of gasification, to study the inactivation mechanism and dynamics of potassium catalyst. Glass reaction was occurred and K2O,SiO2and Al2O3 were compounded as KAlSiO4.It's the main reason for catalyst inactivation.