煤直接液化初始阶段反应特性的研究

以杨村煤为例,在490℃和2倍四氢萘溶剂的条件下,反应仅5 min煤直接液化总转化率就达到84.47%,表明煤在直接液化的过程中具有初始高反应活性的特点。在纯氢气气氛下随着初始压力从1.5 MPa增大到7 MPa,转化率从66.38%上升为83.27%,表明压力大小对煤液化转化率有较大影响。1.5 MPa下溶煤比提高到4:1以后,转化率增大到79.0%就不再增长,表明用添加过量供氢溶剂的方法弥补由于降低系统压力所带来的转化率损失不可行。 Taking Yangcun coal as an example,the reactive characteristic of initial stage in direct coal liquefaction process was studied by using a 17mL micro-autoclave.Under the condition of 490℃ and double amount of tetralin solvent,the total conversion approached 84.47% when the reaction time was only 5 minutes,which showed that coal had an initial high reactivity characteristic in direct liquefaction process.Under pure N_2 atmosphere,the conversion increased from 66.38% to 83.27% as the initial pressure increased from 1.5 MPa to 7 MPa,which showed that besides the contribution to hydrogen-donation the pressure itself of H_2 pressure was also very important.Under 1.5 MPa of N_2 pressure,with the solvent/coal ratio was increased to 4:1,the conversion increased to 79%,but after that it did not increase any more,which showed that the method of adding excessive amount of hydrogen donor solvent to compensate the conversion loss brought by the decrease in system pressure was infeasible