混合冷剂制冷的天然气液化工艺研究与分析

发布时间：2017-12-26 23:06

本文关键词：混合冷剂制冷的天然气液化工艺研究与分析　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：天然气液化过程是一个能耗非常高的过程,出于这个原因,需要研究液化过程的关键因素对流程性能的影响。本论文针对影响液化工艺能耗的因素进行优化,得出天然气预冷后的温度、制冷剂的蒸发压力和冷凝压力、混合制冷剂的组成是降低能耗的关键操作因素,压缩机是LNG厂的主要能耗单元,所以以LNG的比功耗为目标函数,以上述7个影响因素作为优化变量对流程进行优化。用HYSYS优化器优化的结果表明,压缩机的功耗降低32.6%,LNG换热器内冷热复合曲线匹配程度也更好,也就是说LNG换热器的换热效率提升了。考察天然气中甲烷的含量变化,对流程参数进行优化,用MATLAB软件对优化后的结果做拟合,得出混合冷剂配比与比功耗之间的二次多项式拟合方程,对拟合方程进行取值范围内的最小值求解,将其代入实际生产中进行验证,结果表明两者的值分别为3.4973和3.5148,相差为0.5%,误差较小,符合工程要求。在优化后流程的基础上对液化装置进行有效能分析,结果表明天然气液化流程中压缩机的有效能损失最大,提出两种工艺改进方案,一是将混合制冷剂两级压缩改为三级压缩,结果表明压缩机的有效能损失由5028kW降低到4703kW,降低了 6.46%,有明显的效果;二是闪蒸气换热,压缩机的有效能损失由由5028kW降低到4838kW,降低了 3.78%,有效果。
[Abstract]:The process of natural gas liquefaction is a very high energy consumption process. For this reason, it is necessary to study the influence of the key factors of liquefaction process on the performance of the process. This paper focuses on the factors of energy consumption of the liquefaction process was optimized, the natural gas pre cooling temperature, refrigerant condensing pressure, evaporating pressure and mixed refrigerant composition is the key factor to reduce the energy consumption of the operation, compressor is the main energy consumption of LNG plant unit, so as to LNG specific power consumption as the objective function, with the above 7 to optimize the process factors as optimization variables. The result of optimization with HYSYS optimizer shows that the power consumption of the compressor is reduced by 32.6%, and the matching degree of the cold and hot compound curves in the LNG heat exchanger is also better. That is to say, the heat transfer efficiency of the LNG heat exchanger is improved. Study the content changes of the methane in natural gas, the process parameters were optimized, the optimized results fitted by MATLAB software, the mixed refrigerant ratio and ratio of two polynomial fitting equations of power between the minimum solution range of the fitting equation, then the actual production verification, results show that the two values were 3.4973 and 3.5148, the difference of 0.5%, the error is small, meets the engineering requirements. On the basis of improved process of liquefaction device for the effective analysis results show that the maximum effective energy loss in natural gas liquefaction process of compressor, put forward two kinds of improvement scheme, one is the mixed refrigerant two stage compression to three stage compression, the results indicate that the effective energy loss decreased from 5028kW to 4703kW to reduce the compressor. 6.46%, have obvious effect; two is the flash steam heat exchanger, effectively reduced the loss by 5028kW to 4838kW of the compressor is reduced by 3.78%, to have the effect.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE646

【相似文献】