富蜡褐煤化学脱灰及其对萃取的影响

Ash removal of lignite with chemical treatment and its effect on the extraction of montan wax from lignite

化学方法可以除去褐煤中的部分灰分,增加煤中有机质与溶剂的接触面积,影响煤的萃取率和萃取物组成.分别用HCl和NaOH溶液对褐煤进行预处理,考察酸、碱处理对富蜡褐煤灰分脱除的影响;采用多种溶剂萃取,研究褐煤化学脱灰对萃取率、萃取物组成的影响机理.结果表明:对于0.2～10mm富蜡褐煤,酸处理脱灰率随粒度增大先减小后增加,变化范围为13.24%～21.95%,粒径为1～3mm时为最小;碱处理脱灰率随粒度增大而减小,变化范围为72.02%～46.12%.酸处理能提高萃取率,溶剂极性越大,萃取率提高越明显,萃取物中直链烃小分子的含量明显增多;碱液处理会降低萃取率,溶剂极性越大,萃取率降低越大,导致萃取物中非直链烃小分子以外的成分流失.

Parts of ashes in lignite can be removed by chemical treatment, which could increase the contact surfaces between organics and solvents, and influence extraction rate and the com- position of extracts. The effects of acid and alkali pretreatments on the demineralization of lig- nite were investigated by pretreatment in HC1 and NaOH solution, respectively. The influen- cing mechanism of chemical demineralization on the extraction and composition of extracts with several kinds of solvents were studied. The results show that the ash removal ratio decreased first and then increased with the increasing of particle size for 0.2--10 mm coal under acid pre- treatment. The ash removal ratio changed between 13.24% and 21.95%, and the minimum while particle size of 1--3 mm. The ash removal ratio decreased with the increasing of particle size under alkali pretreatment, which changed between ~6.12% and 72.02%. The higher ex- traction ratio was obtained over lignite with acid pretreatment or extracted with stronger polar solvents, meanwhile the content of small chain hydrocarbons in extracts also increased. The lower extraction ratio was obtained over lignite with alkali pretreatment or extracted with stronger polar solvents, and the compounds except non straight-chained hydrocarbons lost fromthe extracts.