用于燃煤电站尿素水解制氨的垃圾焚烧能量利用系统性能分析

Performance analysis of a waste-to-energy system for ammonia production by urea hydrolysis in the coal-fired power plant

为了提高垃圾焚烧系统的发电效率并减少燃煤电站辅助设备的能量损失,以带有尿素水解装置的燃煤机组为例,设计了一种由垃圾焚烧发电系统和燃煤发电系统组成的新型混合能源系统。在这种一体化设计中,移除垃圾发电系统的汽轮机、凝汽器以及发电机等设备,降低了系统的投资成本。集成后的垃圾焚烧锅炉部分预热空气所需热量及其给水由燃煤机组的给水提供,在空气预热器中换热后的热流体送至燃煤机组回热系统,垃圾焚烧机组的锅炉出口蒸汽送入燃煤机组的再热器。此外,在垃圾焚烧发电系统的锅炉尾部烟道布置了一个蒸发器,利用其产生的蒸汽为燃煤发电机组的尿素水解装置供热。通过热力学和经济学方法对独立设计和集成设计进行了分析和比较。结果表明,系统集成后净能量效率从41.71%提高到41.97%,净㶲效率从41.01%提高到41,26%.混合垃圾焚烧发电系统的净能量效率和净㶲效率分别提高了9.58%和9.08%。新型垃圾焚烧发电系统的动态回收期从10.23 a缩短到6.40 a,净现值比原设计增加4901万元。

To improve the power generation efficiency of waste-to-energy system and reduce the energy loss of the auxiliary equipment of coal-fired power plant,taking a coal-fired power unit with the urea hydrolysis device as an example,a new hybrid energy system composed of a waste-to-energy system and a coal-fired power system is designed.In this combined design,the steam turbine,condenser and generator of waste-to-energy system are removed,decreasing its investment cost.The heat required by partial preheated air of the waste-to-energy boiler and its feedwater are both provided by the feedwater of coal-fired power unit,and the hot fluid in the air preheater is sent to the regenerative heating system of coal-fired unit after heat exchange.The outlet steam of waste-to-energy boiler is sent to the reheater of coal-fired power unit.In addition,an evaporator is arranged in the tail flue of the boiler of waste-to-energy system,and the steam generated from it is used to supply heat for the urea hydrolysis unit of the coal-fired power unit.The stand-alone design and the in teg rated design are an alyzed and compared by thermody namic and economic methods.The results show that the total net energy efficiency increases from 41.71%to 41.97%,and the total net exergy efficiency upgrades from 41.01%to 41.26%after system in teg rati on.The net en ergy efficie ncy and net exergy efficiency of the hybrid waste-to-e nergy system increase by 9.58%and 9.08%,respectively.The dynamic payback period of the new waste-to-energy system is cut down from 10.23 years to 6.40 years,and the net present value is enhanced by 49.01 million yuan than before.