小型撬装式天然气液化装置的流程模拟与优化

发布时间：2017-12-28 05:31

本文关键词：小型撬装式天然气液化装置的流程模拟与优化　出处：《宁夏大学》2016年硕士论文　论文类型：学位论文

【摘要】：天然气以其单位热值高、清洁的性能已成为21世纪的主要能源之一,消耗量日益增大。小型液化天然气装置具有体积小、可撬装、机动运输、开停方便等优点,且能对分散的或偏远地区的小型天然气气田进行开发利用,提高能源利用率。本文针对宁夏银川某能源公司的R22预冷混合制冷剂液化循环工艺天然气液化装置进行模拟分析与研究,并对运行过程中的问题进行分析,提出了改进措施。文中利用Aspen Plus模拟软件,建立了R22预冷混合剂制冷液化循环的流程,根据装置的设计参数,对工艺流程进行模拟,并与实际运行参数比较,各参数相对误差在0.03%q%之间,模拟结果与实际运行参数基本吻合,模型选择合理。通过计算可知,每小时70 kmol的天然气可以得到液化天然气(LNG) 62.553 kmol (1042.7 kg),液化率为89.36%,混合制冷剂压缩机功耗为360 kW和R22压缩机功耗为134 kW,比功耗为0.474 kW.h/kgo其与级联式循环相比,相对功耗为1.44,其值与其它液化循环工艺流程比功耗相比处于中间位置,且设备简单、操作方便,是一套比较经济的装置。通过对压缩机、板翅式换热器、节流阀等重要设备进行有效能计算与分析,压缩机炯损失为178.9kW,板翅式换热器炯损失为157.8 kW,节流阀炯损失59.1 kW,水冷凝器炯损失为28.3 kW。炯损失主要是压缩机,其次是板翅式换热器。为了降低炯损失,可以提高压缩机的绝热效率,增加板翅式换热器的换热面积等。将压缩机功耗最小和压缩机功耗与R22预冷量之和最小作为目标函数,以原料天然气进入预冷换热器的温度、高低压制冷剂的压力、温度和天然气中甲烷的摩尔分率为优化变量,对该装置的流程进行了优化,优化后功耗为463 kW,比优化前降低了31 kW。另外,对该装置在运行过程中出现的积液问题和混合制冷剂的充装问题进行了分析,并且提出了改进措施。
[Abstract]:Natural gas has become one of the main energy sources in twenty-first Century with its high calorific value and clean performance, and the consumption of natural gas is increasing. The small LNG plant has the advantages of small volume, skidding, maneuverable transportation, convenient opening and stopping, etc., and it can develop and utilize small natural gas fields in scattered or remote areas, and improve energy utilization. This paper simulates and analyzes the natural gas liquefaction device of the R22 pre cooling mixed refrigerant liquefaction process in an energy company of Yinchuan, Ningxia, and analyzes the problems in the operation process, and puts forward the improvement measures. Using the Aspen simulation software Plus in this paper, a R22 mixture of pre cooling refrigeration liquefaction cycle process, according to the design parameters of the device, process simulation, and compared with the actual operating parameters, the parameters of relative error between 0.03%q% simulation results and actual operation parameters are basically consistent, rational choice model. By calculation, 70 KMOL per hour of natural gas can be liquefied natural gas (LNG) 62.553 KMOL (1042.7 kg), the liquefaction rate is 89.36%, the mixed refrigerant compressor power consumption is 360 kW and R22 compressor power consumption is 134 kW, compared with the power consumption is 0.474 kW.h/kgo and its cascade cycle, relative power consumption is 1.44. The value and the other liquefaction cycle process than in power consumption compared to the middle position, and has the advantages of simple equipment, convenient operation, is a relatively economical device. Based on the important equipment of compressor, plate fin heat exchanger, throttle effective calculation and analysis, exergy loss of 178.9kW compressor, plate fin heat exchanger exergy loss was 157.8 kW, 59.1 kW throttle valve energy loss, water condenser exergy loss was 28.3 kW. Exergy loss mainly compressor, followed by the plate fin heat exchanger. In order to reduce the exergy loss, can improve the adiabatic efficiency of the compressor, plate fin heat exchanger increases the heat transfer area etc.. The minimum power consumption and minimum compressor and compressor power consumption and cooling capacity of R22 as the target function, mole ratio of methane into the pre cooling temperature, high heat pressure refrigerant pressure, feed gas temperature and natural gas as the optimization variables, the same processes were optimized, the optimized the power consumption is 463 kW, 31 kW lower than that before optimization. In addition, the problem of liquid accumulation and the filling of mixed refrigerant during the operation of the device were analyzed, and the improvement measures were put forward.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE96

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