A novel lignite-fired power plant integrated with a vacuum dryer: System design and thermodynamic analysis
A novel lignite-fired power plant integrated with a vacuum dryer: System design and thermodynamic analysis
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DOI：
10.1016/j.energy.2015.01.106
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发表时间：
2015-03
期刊：
影响因子：
9
通讯作者：
Ming Liu;Dongyin Wu;F. Xiao;Junjie Yan
中科院分区：
文献类型：
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作者：
Ming Liu;Dongyin Wu;F. Xiao;Junjie Yan
在进入锅炉之前对褐煤进行预干燥是提高褐煤发电厂净效率的潜在方法。然而，褐煤预干燥是一个高能耗过程，自燃风险很高。如果褐煤在低温下干燥，则可以降低干燥过程中褐煤自燃的可能性。此外，低温能量可以用作干燥热源可以导致发电厂的高净效率。因此，我们设计了一个与真空干燥机集成的褐煤发电厂。我们还利用开发的理论模型对 1000 MW 发电厂的参考案例进行了热力学分析。结果表明，采用低压蒸汽或热泵提供干燥热源，电厂净效率绝对可分别提高2.39%和1.88%。通过对主要因素的分析发现，电厂净效率随着干燥程度的增加而增大，随着干燥机运行压力的增加而减小，而热泵是为干燥提供热源的较好选择，其第二定律效率高于0.76。
Pre-drying of lignite before feeding to the boiler is a potential way to increase the net efficiency of lignite-fired power plants. Lignite pre-drying is, however, a high energy consumption process with a high risk of spontaneous ignition. If the lignite is dried at low temperature, the possibility of spontaneous ignition of lignite in the drying process could be lowed. Furthermore that low temperature energy could be used as the drying heating source may result in a high net efficiency of the power plant. Therefore, we designed a lignite-fired power plant integrated with a vacuum dryer. We also thermodynamically analyzed a reference case of a 1000 MW power plant by using theoretical models developed. The results show that the net efficiency of power plant can be increased by 2.39% or 1.88% absolutely, if a low-pressure steam or heat pump is used to provide the drying heat source, respectively. From analyzing main factors, we discovered that the net efficiency of the power plant increases with the drying degree and decreases with the operating pressure of the dryer, and the heat pump is a better choice to provide the heating source for drying purposes with its second-law efficiency higher than 0.76.