摘要
本文提出了一种利用LNG冷能的新型空分流程,利用LNG冷能冷却进入氮压机的下塔顶部氮气并使其节流液化,部分液体作为产品输出,部分液体流入过冷器后进入上塔顶部完成回流,节流产生的高压氮返回LNG冷能换热器补充冷能。本文采用MATLAB编程对该流程进行计算,并考虑冷热流体在临界区比定压热容随温度剧烈变化的特性,分析氮气压缩机入口温度与总压比对系统能耗、LNG冷能利用率的影响。计算结果表明:氮气压缩机入口温度的降低会同时降低氮压机耗功和LNG冷能利用率,系统等效能耗随其先降低后升高;氮气压缩机总压比的升高会增加氮压机耗功与LNG冷能利用率,但系统等效能耗随之降低;将氮气压缩机入口温度选定为准临界温度时冷能利用系统的等效能耗最低,LNG冷能的利用最高效,相较于已有文献研究结果,本研究所设计新流程的单位液体产品能耗与LNG冷能利用率等指标均有大幅度提高。
In this paper, a novel air separation unit cooled by liquefied natural gas（LNG） cold energy was proposed. The system process was the vapor nitrogen from lower distillation column was cooled by cold energy and compressed by compressor, then changed in to liquid by throttle, one part of them went through sub-cooler to enter in the upper column, the other part of them was output as product. Considering the specific heat capacity varies drastically with temperature near the critical region, the influence of inlet temperature and total pressure ratio of nitrogen compressor on system energy consumption and LNG cold energy utilization rate was analyzed by using MATLAB. The results showed that the decrease of inlet temperature would reduce energy consumption of nitrogen compressor and the utilization of LNG cold energy, and the system equivalent energy consumption first decreased and then increased; the increase of total pressure ratio would increase the nitrogen compressor consumption and cold energy utilization, but decrease the system equivalent energy consumption; When the inlet temperature of the nitrogen compressor was selected as the pseudo-critical temperature, the system equivalent energy consumption was the lowest, and LNG cold energy could be used most reasonably. Compared with the existing literatures, the novel process＇s energy consumption and the utilization of LNG cold energy was greatly improved.
作者
陈仕卿
许剑
谭春青
CHEN Shi-Qing XU Jian TAN Chun-Qing(Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China Ordos QiDi Incubator Service Center, Ordos 017010, China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2017年第8期1607-1612,共6页
Journal of Engineering Thermophysics
基金
国家自然科学基金(No.51206159)
内蒙古自治区自然科学基金重大项目
关键词
LNG冷能
空分流程
准临界温度
冷能利用率
系统等效能耗
LNG cold energy
air separation
pseudo-critical temperature
utilization of LNG coldenergy
system equivalent energy consumption~
