A novel boiler cold-end optimisation system based on bypass flue in coal-fired power plants: Heat recovery from wet flue gas
A novel boiler cold-end optimisation system based on bypass flue in coal-fired power plants: Heat recovery from wet flue gas
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DOI：
10.1016/j.energy.2018.03.129
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发表时间：
2018-06
期刊：
影响因子：
9
通讯作者：
Mingwei Yan;Liang Zhang;Yue-tao Shi;Liqiang Zhang;Yuzhong Li;Chunyuan Ma
中科院分区：
文献类型：
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作者：
Mingwei Yan;Liang Zhang;Yue-tao Shi;Liqiang Zhang;Yuzhong Li;Chunyuan Ma
从燃煤电厂烟气中回收余热并加以合理利用是提高电厂效率的有效途径。旁路省煤器工艺是一种改进的锅炉冷端优化工艺，比传统的低温省煤器工艺具有更大的节能效果。为了更好地实现烟气的梯级利用，提出了一种基于旁路烟道的锅炉冷端优化系统。该工艺将湿式烟气脱硫后的烟气余热回收作为一级热源预热环境空气，减少了空气预热器的传热量，使更多的烟气进入旁路烟道。以一个典型的1000 MW燃煤电厂为例，计算了该工艺的热力性能和技术经济性能，并与旁路烟道工艺进行了比较。热经济性分析结果表明，与原装置相比，该工艺的净标煤耗率可降低5.38 g/（kW·h），比旁路置换工艺的3.62 g/（kW·h）降低1.76 g/（kW·h）。技术经济分析结果表明，15年寿命期的净现值比原装置为2161万美元，比旁路置换工艺的净现值1648万美元增加513万美元。
Recovering waste heat from the flue gas of coal-fired power plants and utilizing it reasonably is an effective way to increase power plant efficiency. The bypass flue process is an improved boiler cold-end optimisation process and has greater energy savings than the traditional low-temperature economizer process. To achieve better stepwise utilization of flue gas, a novel boiler cold-end optimisation system based on bypass flue was proposed in this study. In the proposed process, flue gas waste heat after the wet flue gas desulphurizer was recovered and used as the first-stage heat source to preheat the ambient air, resulting in less heat transfer in the air preheater and more flue gas flowing into the bypass flue. The thermodynamic and techno-economic performance of the novel process were calculated and compared with the bypass flue process, using data from a typical 1000 MW coal-fired power plant. The thermal economy results show that the net standard coal consumption rate of the proposed process could decrease by 5.38 g/(kW·h) compared with the original unit, a 1.76 g/(kW·h) greater reduction than the 3.62 g/(kW·h) of the bypass flue process. The techno-economic analysis results show that the net present value of the 15 years lifespan is 21.61 million USD compared with the original unit, and is 5.13 million USD more than the 16.48 million USD of the bypass flue process.