Correlation between redox capacity and the activity for NO decomposition of various metallosilicates under excess oxygen conditions was studied. The redox capacity was measured by using thermogravimetric analyzer. The metallosilicates having a pentasil poreopening were prepared by the rapid crystallization method. Cu or Co ion-exchanged H-ZSM-5 (Cu/H-ZSM-5 or Co/H-ZSM-5) was used as the reference catalyst. Cu/H-ZSM-5 showed a good correlation between the redox capacity and the activity of NO decomposition, assuming redox reactions occurred between Cu and CuO. Co/H-ZSM-5 also showed a good correlation between them, but the redox reactions occurred between Co2O3 and Co3O4. On the other hand, in the case of metallosilicates, the active metal species were highly dispersed and tightly incorporated into the crystalline lattice, and therefore, the redox capacity did not exert explicitly, and reflecting this, the activity of NO decomposition was considerably low, however, stability of metallosilicates was higher than that of metal ion-exchanged ZSM-5, due to the small change in valency of metals in metallosilicates.
Four kinds of coal chars were gasified in CO2/Ar atmosphere at a temperature of 1173K to 1673K. The reaction rate and ash morphology were investigated at various conversions. At a certain temperature Tx, the reaction rate fell more sharply during gasification than those at other temperatures. This suggests that highly viscous molten ash adhered to the char surface retarded the gasification reaction.
A slovent de-ashing under high temperature and high pressure is adopted in the twostage brown coal liquefaction process to remove ash from the heavy product (coal liquid bottom, CLB) because of its high efficiency. Extract yield and residue properties are very important to develop the solvent deashing process because they affect strongly the CLB recovery and residue handling. Therefore, the effects of temperature and properties of the deashing solvent on the extract yield and residue properties were studied using toluene, cyclohexane and mixture of these as deashing solvents. About a half of preasphaltenes (BI-PS) in the CLBs used was extracted with toluene at 100-250°C. The residue consisted of fine perticles and was handled as a slurry. On the other hand, almost of the preasphaltenes was insoluble in cyclohexane at 250°C although extract yield increased with an increase in temperature. The residue obtained from cyclohexane extraction at above 170°C was sticky, and filtration of the residue was impossible because by plugging up the filter. From these results, it is found that toluene is a suitable solvent for the solvent deashing.