LNG冷能用于发电和空调供冷工艺开发及优化

发布时间：2018-05-13 12:54

  本文选题：液化天然气 + 冷能　； 参考：《华南理工大学》2013年硕士论文

【摘要】：液化天然气（LNG）是天然气经过脱硫处理，通过低温工艺冷冻液化而成的低温液体混合物。LNG作为燃料供给下游用户使用时会释放出大量的冷能，约830kJ/kg，传统工艺中，该部分冷能被海水或空气带走，即造成了能源的浪费，也污染了环境，故此充分回收利用该部分冷能将具有十分重要的理论和现实意义。 目前LNG冷能回收利用面临着资源供应紧张、现货价格和长期合同价格波动剧烈、LNG冷能利用项目建设缓慢、冷能利用方式单一、利用效率低下和冷能用户与冷能供应不同步等问题，使得LNG冷能产业大规模发展受阻。本文结合LNG冷能用于发电及冰蓄冷空调供生活区供冷工艺的优势，根据LNG冷能利用的火用分析和工质与LNG变温曲线趋势变化分析，提出了回收LNG高品位冷能用于发电、低品位冷能用于冰蓄冷空调的分段回收利用工艺。采用流程模拟技术、火用分析法，对比工质在不同流量下的关键设备火用效率变化特点，选取最优的系统参数，，即质量浓度为32%的乙二醇水溶液为冰蓄冷空调使用的工质；若以丙烷与丁烷的混合物作为发电工艺的有机混合工质，最佳混合比为50%-50%丙烷-丁烷（质量分数），当LNG流量为1000kg/hr，设备平均火用效率最大时的混合工质最佳流量为1270kg/hr，蒸发温度为10℃，蒸发压力为0.35MPa，冷凝温度为-22℃，冷凝压力为0.11MPa。 将研究结论应用于某电厂，采用该工艺流程经行工况模拟和分析，运用价值计算和节电效益分析法计算了工况下的LNG冷能回收的经济效益。对于一个LNG气化规模为35000Nm3/hr的气化站，在系统火用效率最大的工况下，回收LNG位冷能用于发电每年的净效益可达到60.3万元，回收LNG冷能用于冰蓄冷空调，每年的节电效益约1078万元，总共经济效益约为1138万元。
[Abstract]:Liquefied natural gas (LNG) is a natural gas after desulphurization treatment. When liquefied natural gas is frozen and liquefied by cryogenic process, when it is used as fuel for downstream users, it will release a large amount of cold energy, about 830kJ / kg. In the traditional process, This part of cold energy is taken away by sea water or air, which not only causes the waste of energy, but also pollutes the environment. Therefore, it is of great theoretical and practical significance to fully recycle and utilize this part of cold energy. At present, the cold energy recovery and utilization of LNG is faced with a tight supply of resources. The spot price and long-term contract price fluctuate sharply. The construction of the cold energy utilization project is slow, and the mode of cold energy utilization is single. The problems of inefficient utilization and the unsynchronization of cold energy users with cold energy supply have hindered the large-scale development of LNG cold energy industry. Combined with the advantages of LNG cold energy used in power generation and ice storage air conditioning supply living area, according to the exergy analysis of LNG cold energy utilization and the trend change analysis of working medium and LNG variable temperature curve, the recovery of LNG high grade cold energy for power generation is put forward in this paper. Low-grade cold energy used in ice storage air-conditioning stage recycling process. By using the process simulation technology and exergy analysis method, the exergy efficiency of the key equipment with different flow rates was compared, and the optimal system parameters were selected, that is, the glycol aqueous solution with mass concentration of 32% was the working medium for ice storage air conditioning. If a mixture of propane and butane is used as an organic mixed working medium in the power generation process, The optimum mixing ratio is 50- 50% propane-butane (mass fraction), when the LNG flow rate is 1000kg / h, the optimum flow rate of the mixture is 1270 kg / h, the evaporation temperature is 10 鈩

本文编号：1883233