压力延迟渗透发电技术的影响因素探究

摘要

压力延迟渗透技术作为提取盐差能的一种有效方法,已在海洋新能源开发方面展现出巨大潜力,提高盐差能发电效率是目前压力延迟渗透技术尚需解决的重要问题之一.以压力延迟渗透过程膜的水通量和功率密度为评价指标,重点研究了料液流动方式、流速和浓度等因素对压力延迟渗透过程性能的影响.结果表明,采用逆流方式、增大浓度差、提高流速均有利于提高压力延迟渗透过程中的水通量和功率密度,其中,单侧增加原料液浓度,水通量和功率密度均呈逐渐降低趋势;单侧增加驱动液浓度,水通量和功率密度均呈逐渐上升趋势.选取河水-正渗透浓盐水模拟体系,采用逆流操作,在压力差为l 200 kPa条件下,提升原料液流速效果更优;驱动液流速为1.OL·min-1,原料液流速从0.5L·min-1提升到2.0L·min-1时,水通量提升了17.3％,功率密度也从8.01 W·m-2增加到9.39 W·m-2.%Pressure retarded osmosis (PRO) technology,as an effective method for harvesting energy from the salinity gradients,has shown great potential in the development of new ocean energy.At present,the improvement of power generation efficiency for the PRO is one of the most important issues to be solved.In this paper,the influences of flow direction,solution concentration and flow velocity on the PRO performances were mainly investigated and evaluated in term of the water flux and power density.And results show that it is beneficial to improving the PRO process water flux and power density by applying the counter-current flow mode,raising the concentration difference across the membrane and increasing the flow velocity.What's more,by unilaterally increasing the feed solution concentration,water flux and power density decrease with increasing feed solution concentration;by unilaterally increasing the draw solution concentration,the water flux and power density increase with increasing draw solution concentration.This paper also chooses the river water-forward osmosis brine simulation system and the results indicate that it is more effective to enhance the feed solution flow velocity by using the counter-current mode under the pressure of 1 200 kPa.And when the draw solution flow velocity is 1.0 L· min-1,the water flux increased by 17.3％ as the feed solution flow velocity increased from 0.5 L·min-1 to 2.0 L· min-1,and the power density also increased from 8.01 W·m-2 to 9.39 W·m-2.