沥青基炭材料的气固相混合活化

COACTIVATION OF PITCHBASED CARBON MATERIALSIN MIXED SOLID AND GAS PHASES

本文研究了由各向同性沥青和中间相沥青制得的各种不同炭材料的混合活化行为，结果发现对于这些炭材料在ＣＯ２和ＫＯＨ中进行混合活化比单独采用ＣＯ２或ＫＯＨ中进行活化效果好得多。与单独ＣＯ２活化相比，在ＣＯ２和ＫＯＨ中进行混合活化能显著提高这些炭材料的活化速率。同时研究了失重率和ＢＥＴ面积的关系，它们遵循如下规律：ＳＰＣＳ＞ＬＰＣＳ＞ＧＰＣＦ＞ＭＰＣＦ＞ＨＭ－ＰＣＦ。混合活化时不同炭材料的表观活化能在７２．５ＫＪ／ｍｏｌ到１１９．８ＫＪ／ｍｏｌ范围内变化。本文将各种炭材料的混合活化特性与它们的晶格参数和微结构进行关联。由各向同性沥青制得的炭纤维和炭微球比由中间相沥青制得的炭材料更易活化。Ｘ—射线衍射数据表明由各向同性沥青制得的炭材料比中间相沥青基炭材料有较小的Ｌａ、Ｌｃ值和较大的ｄ００２值。ＭＰＣＦ在活化时具有皮芯微结构，而ＨＭＰＣＦ却没有这种结构。由于ＭＰＣＦ和ＨＭＰＣＦ具有不同的微结构，造成它们具有不同的失重和不同的ＢＥＴ表面积。

The coactivation behavior of different carbon materials made from isotropic pitch and mesophase pitch simultaneously in solid and gas phases has been studied. It was found that coactivation in CO2+KOH had much greater effect on these carbon materials than activation in CO2 and in KOH alone. Compared to activation in CO2 and in KOH,coactivation in CO2+KOH dramatically increased the reaction rates of the carbon materials studied as well as the values of weight loss and BET surface area which all followed the order SPCS>LPCS>GPCF>MPCF>HMPCF. The apparent activation energies varied from 725KJ/mol to 1198KJ/mol for the different carbon materials in coactivation.The coactivation behavior of the different carbon materials has been correlated with their crystalline parameters and microstructure. Carbonized fibers and spherules made from isotropic pitch are less resistant to activation and coactivation than those made from mesophase pitch. As evident from the Xray data carbon materials made from isotropic pitch have smaller La,Lc,and higher d002 values than mesophase pitch based carbon fibers. MPCF used in activation and coactivation were found to possess skincore type microtexture,while this microtexture was absent in HMPCF. The difference of the weight loss and the BET surface area between MPCF and HMPCF was due to the difference in microtexture of MPCF and HMPCF.