Co-liquefaction properties of Shenfu coal and rice straw

The co-pyrolysis and co-liquefaction behaviors of Shenfu coal (SC) and rice straw (RS) were investigated. The synergistic interaction between SC and RS was examined by comparing the pyrolysis and liquefaction performances of each material with those of their mixtures. TG analysis suggests that the pyrolysis temperature of RS is low. Pyrolysis of RS can form free radicals at lower temperatures, which can promote the pyrolysis of coal when it is co-pyrolyzed with SC, resulting in larger weight losses of their mixture compared to the arithmetic mean values from individual pyrolysis of SC and RS. Co-liquefaction results indicate that there exists an obvious synergistic effect between SC and RS, which is depend on liquefaction conditions. At high liquefaction temperatures and for long reaction time, the synergistic effect decreases because of the increased pyrolysis rate and lack of hydrogen donating ability, resulting in the increased retrogressive condensation reactions. The largest synergistic effect of SC and RS is obtained at 400°C and 60 min with 50% blending of RS. The liquefaction conversion, 14.8%, and hexane soluble fraction, 9.7%, of the co-liquefaction at this optimal condition are higher than the corresponding arithmetic mean values from the individual liquefaction of SC and RS, respectively.