BCND-Ⅱ预聚合催化剂气相聚丙烯中试研究

Study on BCND-Ⅱprepolymerization catalyst in gas-phase polypropylene pilot plant

在12 L间歇聚合小试装置上,采用以1,3-二醇酯为内给电子体的BCND-Ⅱ催化剂制备了预聚合催化剂,并在卧式气相聚丙烯中试装置上进行了丙烯气相聚合,利用SEM、GPC、等规度测试、力学性能测试等方法分析了催化剂的气相聚合行为及其制备的聚丙烯产品的性能。实验结果表明,BCND-Ⅱ催化剂在气相聚合时会出现明显破碎,在高氢气含量下破碎更严重。而预聚合催化剂用于丙烯气相聚合时,聚合活性相比BCND-Ⅱ催化剂提高10%~18%、氢调性能好,制备的聚丙烯颗粒规整度好、细粉含量低、堆密度从0.343 g/mL提高至0.367 g/mL。采用预聚合催化剂可以制备较高等规度、高熔体流动速率聚丙烯产品。

Prepolymerization catalyst was prepared from BCND-Ⅱcatalyst compounded with 1,3 diol-ester as internal electrical donor in a 12 L stainless steel jacketed batch reactor and propylene polymerization was carried out in horizontal gas-phase polypropylene(PP)pilot plant.The polymerization performance in gas-phase and product properties of PP obtained were investigated by SEM,GPC,isotacticity test,mechanical properties test,and so on.The experimental results show that BCND-Ⅱcatalyst particle is significantly fragmented in gas-phase polymerization,which is more serious at higher H2 concentration.When the prepolymerization catalyst is used for gas-phase polymerization,the polymerization activity is increased by 10%to 18%compared with BCND-Ⅱcatalyst,and the response to hydrogen is improved.The PP obtained from the prepolymerization catalyst has good particle regularity,low fine powder,and the bulk density is increased from 0.343 g/mL to 0.367 g/mL.The prepolymerization catalyst can prepare PP with high isotactic index at high melt flow rate.