Abstract

The centrifugal drying response from a sodium acrylate superabsorbent copolymer saturated with water, saline, and a synthetic urine mimic was evaluated. It was hypothesized that drying using mechanical methods might be more economical than through evaporation. Commercial, mid-grade, multi-welled centrifuges capable of speeds as high as 8000 rpm and spin times up to 12 min were used to perform parametric studies of the separations. For centrifugal extraction, meshes that varied average pore size from 28 to 89 micrometers were constructed to contain the saturated superabsorbent polymer while the fluid was driven from it under controlled spinning. Gravimetric determinations post-centrifugation found that 30 − 60% of fluid mass could be extracted. The ionic strength of the saline saturated superabsorbent polymers resulted in a much lower initial saturation volume compared to those saturated with deionized water, and raised the amount of polymer in each tube during centrifugation allowing for higher throughput. Higher fluid extraction is achievable with larger pores in the mesh, although the bigger pores allowed dried particles to propagate through the mesh. Longer centrifugation intervals and higher rotational speeds have only a modest effect on the efficiency and centrifugation used to isolate fluids from saturated desiccants remains incomplete. If the absorbent particles could be tethered together, mechanical drying could be more efficient. Under the best conditions, centrifugation consumes roughly 70 kJ/g (70 MJ/kg) of fluid extracted, which is more than the energy for evaporating water.

摘要

评估了用水、盐水和合成尿液模拟物饱和的丙烯酸钠超吸收性共聚物的离心干燥响应。据推测，使用机械方法干燥可能比通过蒸发更经济。使用速度高达 8000 rpm 和旋转时间长达 12 分钟的商用中级多孔离心机进行分离的参数研究。对于离心萃取，构建平均孔径从 28 到 89 微米变化的网孔以包含饱和的超吸收性聚合物，同时在受控旋转下从其中驱出流体。离心后的重量测定发现可以提取 30 - 60% 的流体质量。与用去离子水饱和的那些相比，盐水饱和的超吸收聚合物的离子强度导致初始饱和体积低得多，并且在离心期间提高了每个管中聚合物的量，从而允许更高的通量。尽管较大的孔允许干燥的颗粒通过网格传播，但较大的孔可以在网格中实现更高的流体提取。较长的离心间隔和较高的转速对效率的影响不大，用于从饱和干燥剂中分离流体的离心仍然不完整。如果吸收性颗粒可以系在一起，机械干燥会更有效。在最佳条件下，离心消耗大约 70 kJ/g (70 MJ/kg) 提取的流体，这超过了蒸发水的能量。