一体式流化床膜反应器合成二甲基二氯硅烷

提出将陶瓷膜与流化床反应器耦合构成一体式流化床膜反应器，用于直接法合成二甲基二氯硅烷。实验考察了催化剂浓度、脉冲反吹对反应效率和膜分离性能的影响，并对反应前后的触体及陶瓷膜进行了表征。结果表明，催化剂浓度小于4%（质量）时，二甲基二氯硅烷的选择性均可维持在85%以上，硅粉转化率随催化剂浓度的增大而增大；催化剂浓度在4%～8%时，二甲基二氯硅烷的选择性随催化剂浓度增加而略有下降，当催化剂浓度大于8%时，二甲基二氯硅烷选择性明显下降。触体失活后粒径减小，硅粉表面积碳随催化剂浓度的增加而升高。陶瓷膜表面形成内外两层滤饼，内层滤饼主要成分为铜，外层滤饼主要成分为碳；不同催化剂浓度下，陶瓷膜对粉尘的截留率均可达100%，反应过程中跨膜压差随时间变化较小，脉冲反吹可增加硅粉转化率。

Synthesis of dimethyldichlorosilane by fluidized bed membrane reactor

A fluidized bed reactor was coupled with a ceramic membrane to construct a integrated fluidized bed membrane reactor for synthesis of dimethyldichlorosilane. The effects of catalyst concentration, back flush on reaction and membrane separation performance were studied. The ceramic membrane and the contact mass before and after reaction were characterized. Selectivity of dimethyldichlorosilane could be maintained above 85% and conversion ratio of silicon increased with increasing catalyst concentration, when catalyst concentration was less than 4%(mass). When catalyst concentration was in the range of 4%—8%, selectivity of dimethyldichlorosilane decreased slightly, but decreased obviously when catalyst concentration was above 8%. The particle size of the contact mass decreased after reaction. The carbon that deposited on the surface of silicon increased with increasing catalyst concentration. Two layers of filter cake formed on the membrane surface during the reaction process. The inner cake was copper, and the outer one was carbon. Under different catalyst concentrations, rejection of dust by the ceramic membrane could reach 100%. The change of trans-membrane pressure was little in the reaction process and back flush could increase silicon conversion.