摘要:目前反渗透系统中泵的运行压力很高,通常在1.8Mpa以上,能耗较高且运行的安全性和可靠性较低。同时,压力越高,膜的压密化越严重,而且是不可逆的。因此,在满足设备出力和水质的条件下降低反渗透的运行压力,对于延长膜的寿命、节能降耗和提高设备运行的安全性和可靠性都具有十分重要意义。
本文通过实验研究了进水温度和操作压力对反渗透运行效果的影响。设计进水水质分别为自来水,CaCl2溶液,NaCl溶液和NaHCO3溶液,调节进水温度分别为20℃、25℃、30℃、35℃,操作压力分别为0.5MPa,0.7MPa,0.9Mpa及1.1Mpa,研究了各操作条件下产水量、回收率、脱盐率的变化规律,得出结论:进水温度升高,回收率增加,产水量增加,脱盐率的下降;压力的升高,回收率增加,产水量增加,脱除盐率升高。
根据实验结论,本文设计了一套10m3/h的太阳能反渗透系统,并计算了各部分参数。系统中利用太阳能适当提高反渗透进水温度,在不减少产水量的条件下降低反渗透运行压力,降低电耗,提高设备运行的安全性和可靠性。净化后的水质可以满足锅炉补给水的要求,且水温较高,可以减少用来加热锅炉补给水的标准煤量,从而减少煤燃烧产生的烟尘、二氧化硫、二氧化碳等环境污染物,具有良好的环境效益、经济效益和社会效益。
关键词: 太阳能,反渗透,水处理
Abstract:Currently, pumps in reverse osmosis systems are running under very high pressure, usually more than 1.8Mpa, consuming high energy and having low operation safty and reliability. Meanwhile, the higher the pressure, the more serious the membrane compaction is, and it is irreversible. Therefore, to reduce the operation pressure under the condition of meeting the requirements of water quality and quantity of reverse osmosis systems is of great significance to extend membrane’s life, to save energy and to improve the operational safety and reliability of equipments.
In this paper, we research the effects of inlet temperature and operating pressure on the reverse osmosis system. The inlet water are tap-water, CaCl2 solution, NaCl solution and NaHCO3 solution, the water temperature are respectively 20℃, 25℃, 30℃, 35℃, operating pressure are 0.5MPa, 0.7MPa, 0.9Mpa and 1.1Mpa. Under differrent operation conditons, we studied the variation of water production, recovery rate and desalination rate and arrived at the conclusion: when water temperature increases, water production and recovery rate increase, but desalination rate declines; when pressure increases, water production, recovery rate increase and desalination rate all increse.
According to experimental results, we designed a set of 10m3/h of solar reverse osmosis system, and calculate the parameters of each part. In the system, solar energy is used to appropriately increase the water temperature, and to lower the operation pressure without reducing the water production, so as to lower power consumption and to improve equipment operation safety and reliability. Purified water with high temperature can meet the requirements of boiler feed water,and can reduce the standard coal used to heat boiler feed water, thereby reducing the smoke produced by coal combustion, sulfur dioxide, carbon dioxide and other environmental pollutants, so the system has good environmental, economic and social benefits.
Keyword: solar energy,reverse osmosis,water treatment
工业发达国家的锅炉耗水量一般占第三位,仅次于冷却水和产品处理。因此锅炉是耗水大户。作为火电汽轮发电机组的重要组成部分,电厂锅炉补给水系统在运行中需要较高品质的水,其补给水常来源于地表水、地下水、沿海及缺淡水的地区还常以海水更甚至污水为补给水源。因此补给水处理技术直接影响到机组的平稳、可靠运行。
锅炉给水处理又称炉外水处理,其主要内容包括原水预处理,除去水源水中的悬浮物质、胶体杂质和有机物等,并对净化水进行脱盐脱气处理。从可持续发展的战略出发,以近年提出的绿色化学新概念为基础,消灭污染源头的绿色锅炉水处理技术应当成为21世纪锅炉水处理发展的中心战略。