蒸汽供热系统工质回收率

凝水回收率做为蒸汽供热系统的节能评价指标之一.已为人们所熟知和重视.然而,凝水回收是否真实反映供热系统的质量回收情况?在节能评价时有没有比它更方便更科学的评价指标来代替?这一指标是否比凝水回收率具有更好的可测得性和可分析性?本文从蒸汽供热的系统角度提出系统工质回收率的概念并依热平衡原理建立工质回收率关系式,使其具有明显的可测得性和便于分析的特性.

Proposal and analysis of a coupled power generation system for natural gas pressure reduction stations

With the increased use of natural gas,it is valuable to study energy recovery ratio in the natural gas pressure reduction stations(PRSs).This paper focused on recovering the energy in PRSs as well as low-grade waste heat by a coupled power generation system(CPGS).The CPGS integrates a natural gas expansion(NGE)subsystem and an organic Rankine cycle(ORC)subsystem driven by low-temperature waste heat.Firstly,a comparative analysis is carried out between the separated natural gas expansion system and the separated ORC system.Then,the effects of heat source conditions,upstream pressure of natural gas and the isentropic efficiency of the natural gas expander are investigated.At last,working fluids selection is conducted with respect to two different pressure ranges of natural gas.The results show that there is an optimal temperature and mass flow rate of the heat source that maximizes the system exergy efficiency.With the increase of the upstream pressure of natural gas,the net power output and waste heat recovery factor increase while the system exergy efficiency has an optimal point.Furthermore,the isentropic efficiency of the natural gas expander has a great influence on the net power output of the system.

不带炉水循环泵直流炉增加冷凝水箱至除氧器管道的结构改进

通过增加一根冷凝水箱至除氧器的连通管及其上的一个控制阀门,做到启动疏水水质合格后的工质回收,从而有效地克服直流炉启动系统不带炉水循环泵的不利因素及化学制水能力的限制和排汽装置真空的限制,解决了锅炉热态冲洗不能连续一次性完成,需要停炉制水,待储水量满足要求后再点火的问题,节约了水资源、缩短了锅炉冷态启动的时间,并给机组的长期运行带来经济效益。