十字形挡板造粒室内干法制粉混料过程数值模拟

为改善干法制粉造粒室内颗粒混合特性,使其具有良好的造粒效果。采用计算流体力学方法,构建欧拉-欧拉双流体模型,对气固两相流场进行数值模拟,分析了十字形挡板造粒室内的压力场、速度场及颗粒体积分数,并结合实验与数值结果进行对比。结果表明:底部加装十字形挡板后,造粒室底部的压力分布状况更为均匀,提高了造粒室内颗粒整体速度;十字形挡板造粒室内颗粒体积分布达到71%,颗粒能够充满造粒室大部分区域,改善了底部颗粒堆积现象;颗粒合格率提高了6. 9%,流动性指数提高了6;实验结果验证了数值模拟的正确性,十字形挡板造粒室有利于促进颗粒混合,提高了颗粒的合格率及流动性,造粒效果更优。

两种尿素大颗粒造粒技术比较

通过对荷兰荷丰公司的两种尿素大颗粒工艺技术的描述,从工艺性能特点、能耗及实际操作等方面进行分析,对这两种技术的优缺点进行比较。

Indoor Particle Contamination in Airlaid Papermaking Workshop

An onsite testing based on eight-site air sampling was carried out in an airlaid papermaking workshop in Tianjin, China. By theoretical calculation, super absorbent polymer （SAP） size and its existent state in indoor static airflow were obtained. SAP content in the sampled air was tested through chemical analysis method and found to be 3.0-7.2 times that of the human health limit in production areas. The concentrations of total suspending particles （TSP） and respirable particles were achieved by weighing. Particles of the most concern differ for varied function areas. Particles smaller than 10μm are mostly produced in the main production process, and 73%-90% particles generated in packing areas are larger than 10μm. SAP raw material particles can easily changed to suspending form by inevitable extrusion and frication. Correlation between respirable particles and TSP agrees well with that in atmospheric environment.

通用型造粒机

Piovan公司的新型低速造粒机RSP15系列产品于2004年6月在市场上推出，这是该公司正在进行的一项改造计划的第一步。该公司宣称，不久将对Piovan所有型号的造粒机实施这项改造计划。RSP15系列产品中有4种是设计用于注射机的，其特点是采用了直径为150mm的闭合转子，而且转子上还有多角叶片，其切断动作象剪刀一样。