燃煤CO_(2)发电系统两级压缩优化

Optimization of Two-Stage Compression Process for Coal-Fired Carbon Dioxide Power System

相对于燃煤水蒸汽发电机组,高参数燃煤CO_(2)发电系统在效率、体积及选材方面都是具有潜在优势的新型发电系统。对燃煤CO_(2)发电系统中压缩冷却流程进行优化研究,以压缩机总耗功和系统效率为评价指标,采用EES软件模拟分析。首先分析常规燃煤CO_(2)发电系统中压缩机部分耗功及压缩机出口温度的变化规律,在此基础上依据能量梯级利用原理,提出优化系统。结果表明:压缩机总耗功随着低压压比增大先减小后增大,即低压压缩机存在最佳低压压比,当主蒸汽参数为30MPa/600℃时,最佳低压压比为1.66,系统效率为44.1%;低压压缩机出口温度随低压压比增加而增大,而高压压缩机出口温度变化趋势相反;优化压缩冷却流程,得到系统效率提高且随低压压缩机入口温度和压比增大而增加,当低压压缩机入口温度为160℃时,系统效率为46.2%,最佳压比为1.325。

In comparison with coal-fired steam generating set,high-parameter coal-fired carbon dioxide power generation system is such a new type of power generation system, which possesses potential advantages in efficiency, equipment volume and material selection. The optimization of the compression and cooling process in the coal-fired carbon dioxide power generation system was researched. Taking total power consumption and system efficiency of the compressor as evaluation indicators, the EES software was adopted to perform the simulation analysis. Firstly, the power consumption in the compressor and the change rule of compressor’s outlet temperature of conventional coal-fired carbon dioxide power generation system were analyzed. On this basis, according to the principle of energy cascaded utilization, an optimization system was proposed.Computation results show that total power consumption of the compressor first decreases and then increases along with the increase of pressure ratio of low-pressure(abbr. LP) compressor,i.e., there exists an optimal pressure ratio for LP compressor.By this time, the main steam parameter is 30 MPa/600℃, the optimal pressure ratio of LP compressor is 1.66, and the system efficiency is 44.1%. The outlet temperature of LP compressor increases with the increase of the pressure ratio of LP compressor, however the variation trend of the outlet temperature of high pressure compressor was opposite. Based on the principle of energy cascaded utilization and optimizing the compression and cooling process, the system efficiency is improved and increases with the inlet temperature and the pressure ratio of the LP compressor. When the inlet temperature of LP compressor is 160°C and the system efficiency is 46.2%, the optimal compression ratio is 1.325.