电力科技与环保2024，Vol.40Issue(2)：142-151,10.DOI:10.19944/j.eptep.1674-8069.2024.02.006
煤电机组宽负荷脱硝改造路线的选择与应用
Research on selection and application of wide-load denitration transformation route for coal-fired power unit
摘要
Abstract
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.关键词
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Key words
wide-load denitration/flue gas bypass,economizer classification/economizer feedwater bypass/hot water re-circulation/economizer flow redistribution/feedwater heating分类
能源科技引用本文复制引用
姚力,王东,许芸,王磊,李志斌,林正根..煤电机组宽负荷脱硝改造路线的选择与应用[J].电力科技与环保,2024,40(2):142-151,10.基金项目
国家重点研发计划(2022YFC3701504) （2022YFC3701504）
