空分系统空气压缩余热自利用性能优化研究

为探究大规模空分系统中空压机余热利用的可行方法,提出利用压缩余热驱动有机朗肯-蒸汽压缩制冷耦合循环,所得制冷量用于空压机入口空气冷却,从而提高压缩系统效率,实现空压机余热自利用和压缩过程自增效的目的。以6万空分规模中空压系统的余热回收为例,利用MATLAB对该余热自利用系统进行了热力学建模;进一步,以系统经济性最大化为目标,针对典型湿度地区的运行工况采用萤火虫算法对主要蒸发器换热面积进行优化。结果表明,在入口空气相对湿度为70%和30%时,该多级空压余热自利用系统的节能率分别可达到4.6%和4.2%,回收周期分别为4.4年和5.5年,系统显示出较好的节能效果和较高的经济价值。     

三角转子膨胀机在跨临界CO2制冷循环中的应用分析

在高压比跨临界CO₂制冷循环中,采用膨胀机替代节流元件对提高循环效率有较大的潜力。分析了以三角转子机械作为膨胀机的运行机理,对三角转子膨胀机的工作过程进行计算和分析,并从形状因子、转子型线、进气角度、偏心距和轴距系数入手,讨论了影响三角转子膨胀机的影响因素。在设定情况下,使用三角转子膨胀机可以通过将10 MPa、313.15 K的超临界CO₂膨胀至3.49 MPa、273.69 K,并将制冷系数提高23.7%。形状因子和进气角度是影响膨胀机运行效果的主要因素,需选取适当的参数来提高效率。     

Introducing a proper hydrogen liquefaction concept for using wasted heat of thermal power plants-case study: Parand gas power plant

A hydrogen liquefaction concept with an innovative configuration and a capacity of 4 kg·s^-1 (345.6 t·d^-1) is developed. The concept involves an ammonia absorption refrigeration system for the pre-cooling of hydrogen and MR streams from 25 ℃ to -30 ℃. The ammonia absorption refrigeration system is fed by exhaust gases of the Parand gas power plant that are normally dissipated to the environment with a temperature of 546 ℃. The simulation is performed by Aspen HYSYS V9.0, using two separate equations of state for simulating hydrogen and MR streams to gain more accurate results especially for ortho-para conversion. Results show that conversion enthalpy estimated by Aspen HYSYS, fits very well to the experimental data. Determining the important independent variables and composition of MRs are done using trial and error procedure, a functional and straightforward method for complicated systems. The minimum temperature limit in the cooling section is lowered, and an ortho-para converter is implemented in this section. The proposed concept performs well from energy aspects and leads to COP and SEC equal to 0.271 and 4.54 kW·h·kg^-1, respectively. The main advantage of this study is in the low SEC, eliminating the losses of the distribution network, and improving the ability of the hydrogen liquefaction for energy storage in off-peak times.     

凝析气田开发后期处理厂工艺改进

凝析气田处理厂通过节流制冷脱水脱烃来控制天然气的露点,气田开采中后期由于压力逐年递减,导致外输气不能满足烃露点要求。通过HYSYS软件模拟计算和工艺比较,得出"JT阀前增压+丙烷制冷脱水脱烃工艺"可以满足气田中后期的外输气烃露点要求。     

Simulation-optimization of solar-thermal refrigeration systems for office use in subtropical Hong Kong

The solar-thermal refrigeration systems, covering the solar absorption refrigeration system (SAbRS) and the solar adsorption refrigeration system (SAdRS), were designed for typical office in the subtropical Hong Kong. The approach of simulation-optimization was adopted in order to determine the optimal design parameters for SAbRS and SAdRS against the conventional design practice. For simulation, dynamic model of each system was refined on the TRNSYS platform. For optimization, the objective was to minimize the annual primary energy consumption of SAbRS or SAdRS in response to the changing loading and climatic conditions throughout a year. This is a constrained optimization problem since the upper limit of comfort temperature was stipulated, such that the minimization of system energy would not sacrifice the indoor thermal comfort. Due to the complex, multidimensional and constrained nature of the dynamic simulation models, the differential evolution (DE), which has been proven effective in evolutionary computation (EC), was used for optimization purpose. Through the simulation-optimization run, the optimized designs of SAbRS and SAdRS were determined, and their corresponding primary energy consumptions could be 12.2% and 7.1% less than those based on the general design practice. The results provide useful guidelines for the equipment design of SAbRS and SAdRS.     

Constructal design of distributed cooling on the landscape

Here we constructal design to determine the area size (or number of users N) to be allocated to a central refrigeration plant, and to configure the distribution network for the distributed cooling system. The main objective is to maximize the net cooling capacity delivered to every user, and to minimize the pumping power required for transporting the chilled water. Two types of distribution networks are investigated: radial and tree‐shaped networks. First, when ducts with a single diameter are used, the net cooling capacity delivered to every user is almost the same, while the pumping power requirement for the tree network is greater than that for the radial network. Multi‐diameter tree networks are investigated next. The pumping power requirement for multi‐diameter tree‐shaped network is less than for radial network when N is greater than 19 if the flow is laminar, and when N is greater than 80 if the flow is turbulent. The global performance of the area‐based cooling system can be improved by increasing the freedom to morph the configuration. Copyright © 2010 John Wiley & Sons, Ltd.     

氨液制冷系统设计及其工程应用

介绍了氨液制冷系统的工艺技术及其特点,以及在实际工程中的应用。     

溴化锂制冷机组循环水腐蚀对策

气体分馏装置溴化锂制冷机组循环水系统腐蚀相当严重 ,水冷设备经常因腐蚀而造成泄漏。文章对其腐蚀机理进行了分析 ,指出循环水中的溶解氧是造成设备电化学腐蚀的主要原因。采用物理和化学相结合的方法 ,通过安装多功能电子除垢仪和注入锈垢净后 ,经过近一年的现场运行观测 ,溴化锂制冷机组循环水系统腐蚀问题得到了解决     

从发电煤耗看热电冷联供系统的热经济性

首先引入热电冷联供系统发电煤耗概念,然后从系统整体的角度分析了热电冷联热系统的热经济性。     

烷基苯冷冻机油基础油

烷基苯具有优异的低温性能、添加剂溶解性能,热氧化安定性能和电绝缘性能,是一种性能突出的合成冷冻机油的基础油.