首页|煤电机组宽负荷脱硝改造路线的选择与应用

煤电机组宽负荷脱硝改造路线的选择与应用

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  • 国家科技期刊平台
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  • NSTL
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为解决深度调峰工况下，燃煤机组存在脱硝系统入口烟气温度偏低而无法满足脱硝系统催化剂安全运行温度的要求，对比分析了6种常见的宽负荷脱硝技术的优缺点，对应用结果进行核算分析，探讨其适用条件。结果表明:(1)烟气旁路改造方案，采用多烟道抽取高温烟气的方式，能够缩小旁路烟道挡板尺寸，可大幅降低烟气旁路漏量，同时改善烟气旁路调节的灵活性;(2)省煤器分级技术方案，对锅炉效率影响较小，但需注意满负荷烟气温度超限运行和低负荷一二次风温度降低影响低负荷稳燃的问题;(3)烟气旁路或省煤器流量置换改造方案，对于欠温幅度大于30℃的亚临界机组建议采用该方案，无启动循环泵的超(超)临界机组可以结合干湿态转换需求同步增加炉水循环泵来实现机组宽负荷脱硝，不建议开展基于省煤器出口热水循环至省煤器入口的流量置换(或复合热水再循环)改造;(4)直接调节尾部烟气挡板方案，对于尾部双烟道布置且省煤器单侧布置的机组，可通过直接调节尾部烟气挡板来实现20%以上负荷宽负荷脱硝。综合对比，除省煤器分级改造方案以外，其他通过提高脱硝系统入口烟气温度的方案均会增加机组能耗，脱硝入口烟温每提高1℃，导致锅炉效率约降低0。02%。所述改造方案可以为煤电机组开展相关工作提供参考。
Research on selection and application of wide-load denitration transformation route for coal-fired power unit
Under the condition of deep peak regulation,the temperature of flue gas at the inlet of denitrification system in coal-fired units is too low to meet the requirements of safe operation temperature of catalyst in denitrification system.The advantages and disadvantages of six common wide load denitrification technologies are compared and analyzed,and the application results are calculated and analyzed,and the applicable conditions are discussed.The results show that:(1)In the flue gas bypass retrofit scheme,the size of the bypass flue baffle can be reduced by using multiple flues to extract high-temperature flue gas,which can greatly reduce the leakage of the flue gas bypass and improve the flexibility of the flue gas bypass adjustment;(2)The technical scheme of economizer classification has little effect on boiler efficiency,but it is necessary to pay attention to the problem that the over-limit operation of flue gas temperature at full load and the decrease of primary and secondary air temperature at low load affect the stable combustion at low load;(3)Flue gas bypass or economizer flow replacement transformation scheme.It is recommended to adopt this scheme for subcritical units with undertemperature range greater than 30℃.The ultra-supercritical(ultra-supercritical)units without starting circulating pump can simultaneously increase the boiler water circulating pump in combination with the dry and wet state conversion requirements to achieve wide load denitrification of the unit.It is not recommended to carry out flow replacement(or composite hot water recirculation)transformation based on the hot water circulation at the economizer outlet to the economizer inlet;(4)Directly adjust the tail flue gas baffle scheme.For the unit with double tail flues and one side of the economizer,the tail flue gas baffle can be directly adjusted to achieve more than 20%load wide load denitrification.Through comprehensive comparison,except for the economizer grading transformation scheme,other schemes by increasing the inlet flue gas temperature of the denitration system will increase the energy consumption of the unit.For every 1℃increase in the inlet flue gas temperature of the denitration system,the boiler effi-ciency will be reduced by about 0.02%.The transformation scheme can provide reference for thermal power units to carry out related work.

wide-load denitrationflue gas bypass,economizer classificationeconomizer feedwater bypasshot water re-circulationeconomizer flow redistributionfeedwater heating

姚力、王东、许芸、王磊、李志斌、林正根

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低碳智能燃煤发电与超净排放全国重点实验室(国家能源集团科学技术研究院有限公司),江苏 南京 210023

宽负荷脱硝 烟气旁路 省煤器分级 省煤器给水旁路 省煤器流量置换 给水提温

国家重点研发计划

2022YFC3701504

2024

10.19944/j.eptep.1674-8069.2024.02.006

电力科技与环保
国电科学技术研究院

电力科技与环保

影响因子：0.653
ISSN：1674-8069
年,卷(期)：2024.40(2)
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