高参数生物质循环流化床锅炉技术研发与应用

Development and application of high-parameter biomass-fired circulating fluidized bed boiler technology

发展生物质直燃循环流化床(circulating fluidized bed,CFB)锅炉技术对促进我国能源转型和双碳目标的实现具有重要意义。将高温受热面布置在炉内,利用循环物料持续冲刷清洁受热面可有效抑制沾污和腐蚀。对于尾部对流受热面积灰和沾污,则可采用顺列管束布置方式,以及大节距、小管径、低烟速和平行流设计予以解决。除利用生物质夹带黏土缓解床料结焦外,通过提升物料循环系统性能改善包括燃料颗粒在内的流化质量,并辅以床温有效调控手段,从而通盘解决生物质锅炉燃烧效率和全回路防结渣团聚问题。基于该技术开发的3台高蒸汽参数生物质CFB锅炉可在宽负荷范围内稳定运行,未发生过因受热面积灰结渣导致的停炉,锅炉效率超过91%,NO_(x)和SO_(2)原始排放直接满足超低排放要求,各项性能指标基本达到甚至优于设计要求。

The development of biomass-fired circulating fluidized bed(CFB) boiler technology is critical for the energy transformation as well as and carbon neutrality in China.By arranging the high-temperature heating surfaces inside the furnace,the slagging and corrosion on surface can be effectively lightened through continuous wash and clean by solid circulating materials.Meanwhile,the ash deposition and fouling on convective heating surfaces at the tail flue can be mitigated by applying in-line tube bundles and parallel flow design,as well as increasing the tube spacing,reducing the tube diameter and lowering the gas velocity.For comprehensively solving the particle agglomeration in the whole circuit and further increasing the boiler combustion efficiency,the performance of solid circulation loop is necessary to be improved and the bed temperature should be accurately selected and controlled.Besides,properly injecting some clay carried by feeding biomass to furnace can also alleviate the agglomeration of bed materials.Three biomass-fired CFB boilers with high steam parameters were designed and constructed based on the technical routes introduced in this paper.Industrial practice showed that all of them can be operated stably in a wide load range,and no shutdown accident happened due to slagging and corrosion on heating surfaces.The boiler efficiency generally exceeded 91%,and the ultra-low NO_(x) and SO_(2) emission standards were directly satisfied without using any flue gas denitrification nor desulfurization device.Various performance indicators basically met or even exceeded the design requirements.