摘要：Liquefied natural gas(LNG) is the most economical way of transporting natural gas(NG) over long distances. Liquefaction of NG using vapor compression refrigeration system requires high operating and capital cost. Due to lack of systematic design methods for multistage refrigeration cycles, conventional approaches to determine optimal cycle are largely trial-and-error. In this paper a novel mixed integer non-linear programming(MINLP)model is introduced to select optimal synthesis of refrigeration systems to reduce both operating and capital costs of an LNG plant. Better conceptual understanding of design improvement is illustrated on composite curve(CC) and exergetic grand composite curve(EGCC) of pinch analysis diagrams. In this method a superstructure representation of complex refrigeration system is developed to select and optimize key decision variables in refrigeration cycles(i.e. partition temperature, compression configuration, refrigeration features, refrigerant flow rate and economic trade-off). Based on this method a program(LNG-Pro) is developed which integrates VBA,Refprop and Excel MINLP Solver to automate the methodology. Design procedure is applied on a sample LNG plant to illustrate advantages of using this method which shows a 3.3% reduction in total shaft work consumption.

摘要：英国制冷学会(IOR)日前公布了有关CO2制冷系统的安全标准修订,主要涉及压力系统安全法规(PSSR)要求。所有相关机构和人员,包括业主、运营、安装或此类系统的设计人员都应对此安全标准高度重视。根据压力系统安全法规2000版表1豁免条款第18条,压缩机电机功率不超过25kW的CO2蒸汽压缩制冷系统将可以排除在外。总的来说,CO2系统的运行压力超过40bar,由此使其成为拥有巨大能量的压力容器。这样的系统符合PSSR目录中等压力容器的描述。

摘要：在合成氨装置生产运行过程中,氨压缩制冷系统不凝气的存在,不仅增加了氨压缩机的功耗,而且对制冷设备的安全运转造成了威胁.所以,氨压缩制冷过程中不凝气的排放是不可缺少的,而且如何进行有效而经济的排放就显得更为重要.笔者针对一个典型的不凝气排放方案,从流程的配置方面进行了技术改造,达到了节约投资和节省占地的目的.以下简要介绍.

摘要：为解决目前家用膜过滤式纯净水机需要定期清洗和更换滤芯的弊病,本文基于增湿去湿(HDH原理和压缩制冷工作原理设计搭建了一种新型家用纯净水制备系统,在模拟全年运行工况(即不同的系统进水温度)下对该系统的产水特性进行测试,并进行经济性分析。结果表明:进水温度为15℃时,系统工作效率(即单位能耗纯净水产水量)最高,为1,996 g/(kW·h);较低的进水温度(5℃～10℃)可有效降低系统功耗;较高的进水温度(20℃～25℃)有利于提高纯净水产水量;系统纯净水产水量不低于580 g/L,脱盐率高达97%;与典型反渗透膜式净水器相比,本系统初投资较大,但运行费用大大降低,长期使用更具经济性。