半焦催化裂解煤焦油试验研究

Experimental study on catalytic cracking of coal tar by semi-coke

为了提高褐煤热解制得半焦对焦油的催化裂解效果,采用煤热解制备的半焦催化裂解煤热解过程中产生的煤焦油。采用两段式固定床反应器,在反应器上段放置煤样热解,下段放置半焦催化剂催化裂解上段产生的焦油。研究了制焦温度、半焦用量、经O 2活化后半焦对焦油催化裂解效果的影响。结果表明,增加褐煤的制焦温度,焦油产率明显下降,褐煤900℃制备的活化半焦1 g时的焦油产率仅6.3%,提高半焦制焦温度有利于焦油中的大分子芳香类物质催化裂解成少环物质和小分子气体组分;增加半焦用量对焦油脱除效果作用不明显,焦油产率缓慢减少。与未活化半焦相比,O 2活化后的半焦对焦油的脱除效果更好。半焦的比表面积及孔隙分析(BET)表明,活化后半焦的比表面积更大,且孔隙更丰富;能谱分析(EDS)发现,活化后半焦表面金属元素总量高于未活化半焦。

In order to improve the catalytic cracking effect of semi-coke from lignite pyrolysis on tar,the semi-coke prepared by coal pyrolysis was used to catalyze the pyrolysis of coal tar.Two-stage fixed bed reactor was used to study the effects of coking temperature,char consumption and oxygen activation on the catalytic cracking of tar.Coal samples were placed in the upper section of the reactor for pyrolysis,and semi-coke catalyst was placed in the lower section to catalyze the pyrolysis of tar produced in the upper section.The results show that the yield of tar decreases obviously with the increase of coking temperature of lignite.The yield of tar is only 6.3% when the activated semi-coke prepared from lignite at 900℃ is 1 g.Increasing the coking temperature is beneficial to the catalytic cracking of macromolecular aromatics in tar into less-loop substances and small-molecule components.Increasing the char consumption has no obvious effect on tar removal,the tar yield decreases slowly.Compared with the unactivated char,the char activated by O2 has better removal effect on tar.Specific surface area and pore analysis of semi-coke(BET)show that the activated char has larger specific surface area and more pore space.Energy spectrum analysis(EDS)shows that the total amount of metal elements on the surface of activated char is higher than that of unactivated char.