脱硝还原剂液氨改尿素技术路线研究

Research on the Technical Route of Changing Denitration Reducing Agent Liquid Ammonia to Urea

摘要: 液氨储量超过10吨属于重大危险源，运输、贮存和使用过程均存在安全隐患。电厂现有脱硝液氨罐区属于重大危险源，液氨在运输、贮存和使用过程中存在较大的安全隐患。根据日趋严格的安全形势要求及从电厂安全生产风险防控的实际需求出发，脱硝还原剂供应由液氨改为尿素工艺是必要的。综合尿素水解和尿素热解的技术和经济性对比，电加热尿素热解、烟气换热尿素热解、尿素水解(含催化水解)、尿素直喷制氨技术在原理上、实际应用方面均可行、且有实际改造案例。电加热尿素热解制氨技术方案电耗大、运行问题多，经济性和稳定性均不佳，故不建议新建机组或改造工程项目采用该技术方案。尿素水解制氨技术(含催化水解)和烟气换热尿素热解制氨技术运行稳定、安全性好。可根据上述技术适用条件，针对各厂的实际情况进行选择。

Abstract: Liquid ammonia reserves of more than 10 tons are a major source of danger, and there are potential safety hazards during transportation, storage and use. The existing SCR liquid ammonia area of the power plant is a major source of danger, and liquid ammonia has potential safety hazards during transportation, storage and use. In accordance with the increasingly stringent requirements of the safety and environmental protection situation and from the actual needs of power plant safety production risk prevention and control, it is necessary to change the supply of reducing agent in the denitration system from liquid ammonia to urea. According to the technical and economic comparison of urea hydrolysis and urea pyrolysis, electric heating urea pyrolysis, flue gas heat exchanger urea pyrolysis, urea hydrolysis (including catalytic hydrolysis), urea direct injection ammonia technology are feasible in principle and in practical application, and there are practical transformation cases. The technical solution of urea pyrolysis (electric heating) consumes a lot of electricity, has many operational problems, and has poor economy and stability. Therefore, it is not recommended to adopt this technical solution for new units or technical renovation projects. Urea hydrolysis technology (including catalytic hydrolysis) and urea pyrolysis (flue gas heat exchange) technologies are stable and safe. The selection can be made according to the above technical application conditions and the actual conditions of each plant.