脱除烟气SO3实现SCR宽负荷脱硝的可行性分析

为适应火电机组灵活性改造要求，机组需在超低负荷下安全稳定运行，其中低负荷脱硝改造是重要组成部分。分析了以往燃煤机组SCR脱硝系统低负荷下退出的原因，介绍了宽负荷脱硝改造方案，其主要包括：提高SCR入口烟温技术，使用宽温度范围催化剂和采用碱性吸附剂脱除烟气中SO₃技术。从初投资、改造工期、改造效果、其他收益等方面全面比较了各方案优缺点，提出“因厂制宜，因机制宜”的改造思路。同时指出，由于碱性吸附剂脱除SO₃技术具有消除蓝色烟羽、预防空气预热器堵塞、防治设备腐蚀、减少脱硫废水产生量和重金属协同脱除等其他技术不具备的额外收益，未来应加快发展。

Feasibility Analysis on the Application of SO3 Removal Technology in Coal-fired Power Units at Low Load SCR Operation

In order to meet the requirement of the flexibility reconstruction projects in coal fired power plants, it is necessary to ensure the safe and stable operation of the units at low load. The low load SCR denitration is an important part of the flexibility reconstruction project. This paper analyzes why SCR reactor exits when the coal-fired boiler operates at low load, reviews the development of the SCR technology under full load, and introduces some typical retrofitting schemes to improve the adaptability of SCR at low load. These retrofitting schemes are compared with the original design from the aspects of initial investment, retrofitting schedule, effectiveness and other benefits. The specific situation of the plants or units should be considered as well. In addition, the alkaline sorbent injection technology is more practical in engineering, as it has some other benefits such as curing plume visibility, preventing the APH plugging, resolving equipment corrosion, reducing the desulfurization waste water and synergistic removal of heavy metals.