基于响应曲面法的太阳能膜蒸馏优化实验研究

发布时间：2019-05-15 10:41

【摘要】：传统海水淡化技术,消耗常规能源,能耗高,对环境产生污染,膜蒸馏技术可在中低温工况下运行,因此,可将膜蒸馏与太阳能等低品位能源结合。传统研究一般采用单因素分析方法,不能有效分析各个操作参数之间的相互影响关系。因此,本研究将太阳能光热光电系统耦合中空纤维膜蒸馏组件,运用响应曲面法设计分析实验工况,搭建完全依靠太阳能为膜蒸馏系统提供能量的实验平台,分析操作参数之间的相互影响关系,研究最佳操作工况下的最优膜通量和能耗,从理论和实验两方面展开研究。首先,搭架太阳能光热光电中空纤维膜蒸馏系统实验平台,选择全玻璃真空管集热器为膜组件提供热能,采用光伏组件为系统提供电能,为充分利用太阳能,将集热器和光伏组件并列安装在全自动双轴太阳能跟踪平台上,耦合中空纤维膜蒸馏组件系统,研究不同操作参数对膜通量的影响。其次,运用响应曲面法(response surface methodology,RSM)对太阳能膜蒸馏系统中的操作参数和膜通量进行分析,结合中心复合设计法优化设计了两种不同工况下的实验。根据响应曲面法设计的实验工况在搭架的实验平台上进行实验,收集分析两种工况下的实验数据并录入软件进行优化模拟。运用Design-Expert软件对实验数据进行分析,建立二次模型进行回归拟合,获得响应曲面图和等高线图,分析操作参数对膜通量响应值的影响及各个参数之间的相互影响关系,得出操作参数的最优工况及最优膜通量响应值。研究表明,考虑膜组件进口温度、膜组件进口流量和真空度三个操作参数下的二次回归模型显著,重要性因子F=21.33,决定性系数R2 =0.9505,预测膜通量与实验膜通量相关性强。模拟分析的最佳工况为进口温度为63℃,流量为237L/h,真空压力为0.75×105Pa,此最佳工况下的预测膜通量为6.05kg/(m2·h),实验膜通量为6.26kg/(m2·h),二者误差为3.35%。考虑膜组件进口温度、膜组件进口流量和太阳辐射度三个影响因素下的二次回归拟合模型中F=9.2,R2=0.8922,方差分析表明模型拟合良好。此工况下模拟分析的最佳工况为温度为63℃,流量为232L/h,辐射度为700w/m2时,预测膜通量为6.44kg/(m2·h),实验膜通量为7.24kg/(m2·h),两者误差为11.05%。最后,搭架的实验平台首次实现完全依靠太阳能为膜蒸馏系统提供能量,因此,分析呈现了实验系统运行中电流、电压、功率等物理参数的变化趋势,分析了耗电量、真空度和膜组件进料液温度对膜通量的影响。根据实验数据,对系统的热耗、能耗和发电效率进行了简要的热力学分析。
[Abstract]:Traditional seawater desalination technology consumes conventional energy, high energy consumption and pollution to the environment. Membrane distillation technology can operate at medium and low temperature, so membrane distillation can be combined with solar energy and other low-grade energy. The traditional research usually adopts single factor analysis method, which can not effectively analyze the interaction between the operating parameters. Therefore, in this study, the solar photothermal optoelectronic system is coupled with the hollow fiber membrane distillation module, and the experimental conditions are designed and analyzed by using the response surface method, and the experimental platform which relies entirely on solar energy to provide energy for the membrane distillation system is built. The interaction between the operating parameters is analyzed, the optimal membrane flux and energy consumption under the optimal operating conditions are studied, and the theoretical and experimental studies are carried out. First of all, the experimental platform of solar photothermal optoelectronic hollow fiber membrane distillation system is set up, the all-glass vacuum tube collector is selected to provide heat energy for the membrane module, and the photovoltaic module is used to provide electric energy for the system, in order to make full use of solar energy. The collector and photovoltaic module are installed side by side on the automatic biaxial solar tracking platform, and the hollow fiber membrane distillation module system is coupled to study the influence of different operating parameters on the membrane flux. Secondly, the operating parameters and membrane flux in the solar membrane distillation system are analyzed by using the response surface method (response surface methodology,RSM). Combined with the central composite design method, the experiments under two different working conditions are optimized. According to the experimental conditions designed by the response surface method, the experiments are carried out on the experimental platform, and the experimental data under the two working conditions are collected and analyzed and input into the software for optimization simulation. The experimental data are analyzed by Design-Expert software, the quadratic model is established for regression fitting, the response surface diagram and contour diagram are obtained, and the influence of operation parameters on the response value of membrane flux and the interaction among each parameter are analyzed. The optimal operating conditions and membrane flux response values of the operating parameters are obtained. The results show that the quadratic regression model considering the inlet temperature, inlet flow rate and vacuum degree of the membrane module is significant, the importance factor F 鈮，

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