基于煤干燥技术与乏汽GGH的燃煤电站清洁高效协同系统

A clean and efficient system for coal-fired power stations based on coal pre-drying and exhaust steam gas-gas heater

低温省煤器与气-气换热器(GGH)分别具备良好的节能与环保效果,但二者无法同时布置。对此,本文提出燃煤电站清洁高效协同系统,该系统应用煤干燥技术,在燃煤电站的锅炉尾部布置低温省煤器,在干燥装置尾部布置GGH,以同时达到节能与环保效果。针对所提出的清洁高效协同系统,以典型超超临界1 000 MW一次再热机组为案例,以传统低温省煤器系统与GGH系统作为参比系统,进行了热力学分析与经济性分析。结果表明:新清洁高效协同系统能增加发电量14.7 MW,回收水分13.9 kg/s,增加收益2 624万元/a,节能效果与经济效益显著;能够提升最终排烟温度到80℃以上,有效提升烟气浮升力与污染物稀释能力,同时降低CO_2排放量54 134 t/a。

Both the low temperature economizer and gas-gas heater （GGH） have good energy saving effect and environmental protection effect, but they could not be arranged simultaneously in coal-fired power plants. To solve this problem, a clean and efficient coordinated system was put forward. In this system, by using coal pre-drying technology, a low-temperature economizer is arranged in tail of the boiler while a GGH is arranged after the dryer. Moreover, by taking a typical ultra supercritical 1 000 MW unit coal-fired unit with single reheat cycle as case unit and the conventional low temperature economizer and GGH systems as reference systems, thermodynamic and economic analysis of the new system were conducted. The results indicate that, the proposed system will increase the power production by 14.7 MW and recover water of 13.9 kg/s, which can bring annual economic benefit of 26.24 million yuan, indicating the energy saving effect and economic benefit is dramatic. The final exhaust temperature will be heated up to over 80 ℃, and the buoyancy lift and pollutant dilution capacity of the flue gas can be greatly enhance. Furthermore, the annual CO2 emission reduction in the proposed system will be 54 314 t, which resulted in benefit to pollutant attenuation and environmental protection.