| Popis: |
The properties of the heavy organic products (b.p. above 420°C, coal liquid bottom, CLB) derived from Victorian brown coal under various liquefaction conditions (temperature of 430–470°C, pressure of 9.8–24.5 MPa and solvent or bottom recycle modes) were investigated by using continuous process development units. The various CLBs and their solvent extraction fractions were characterized by ultimate analysis, 1 H-NMR, GPC and solvent extraction. With increase in severity of reaction conditions, the CLB yield and molecular weights of asphaltenes and preasphaltenes decreased. The changes in the structural parameters of the CLBs were explained by dealkylation and dehydrogenation reactions and elimination of oxygen from the heavier products. The elimination which is promoted by increase in the reaction temperature and pressure contributed to reduce the yield and molecular weight of the CLB. |
