1000 MW火电机组超低排放改造的FGD性能试验分析

Experimental Analysis on FGD Performance of Ultra-Low Emission Modification of 1000 MW Thermal Power Unit

为满足《煤电节能减排升级与改造行动计划(2014—2020年)》《全面实施燃煤电厂超低排放和节能改造工作方案》以及《广东省煤电节能减排升级与改造行动计划(2015—2020年)》的要求,以机组的烟气NO_(x)、SO_(2)、烟尘的排放浓度分别控制在50 mg/m^(3)、35 mg/m^(3)、5 mg/m^(3)以内为目标,广东省某燃煤电厂对4#号机组脱硫系统进行超低排放改造。脱硫系统改造方案为:更换两台浆液循环泵,两层喷淋层+增加一台浆液循环泵和一层喷淋层+脱硫增效装置,吸收塔不重建,不新增吸收塔,对原吸收塔进行加固,原有氧化风机的流量不能满足要求,每套脱硫氧化风系统增加一台罗茨氧化风机。工况原则:脱硫系统总阻力不大于2700 Pa(吸收塔进口膨胀节至吸收塔出口膨胀节之间的阻力);该脱硫系统改造工程采用塔内高效脱硫装置,脱硫效率>99%;该脱硫系统改造工程入口烟尘含量35 mg/m^(3),出口烟尘含量小于20 mg/m^(3);该脱硫系统改造工程采用高效除雾器(一层管式除雾器+两级屋脊式除雾器),脱硫出口液滴含量小于40 mg/m^(3)。改造后1000 MW机组脱硫系统开展了有关性能参数的试验研究,在1000 MW、800 MW、400 MW三个工况下,对脱硫效率、工艺水耗量、石灰石耗量、电量消耗、石膏品质、净烟气液滴含量、进出口SO_(2)、净烟气烟尘浓度等FGD各指标参数进行试验。试验结果显示测试指标均能满足设计的性能保证值。改造机组完成超低排放改造并投入运行已满三年,总体上FGD系统设备运行良好,各项排放指标均达到“50、35、10”超洁净目标,实测排放数据远低于年度总量减排控制目标,可为同类工程提供参考。

In order to meet the requirements of the national three ministries and commissions《Action Plan for Upgrading and Renovating Energy Saving and Emission Reduction of Coal and Electricity(2014-2020)》,《Comprehensive implementation of coal-fired power plant ultra-low emissions and energy-saving renovation work plan》and《Action Plan for Upgrading and Renovating Energy Saving and Emission Reduction of Coal and Electricity in Guangdong Province(2015-2020)》,the flue gas NO_(x),SO_(2)and dust emission concentrations of the unit were controlled within 50 mg/m^(3),35 mg/m^(3)and 5 mg/m^(3),respectively.A coal-fired power plant in Guangdong Province carried out ultra-low emission transformation of the desulfurization system of Unit 4.The retrofit scheme of the desulfurization system is as follows:replacing two slurry circulating pumps and two spray layers+adding one slurry circulating pump and one spray layer+desulfurization efficiency device.The absorption tower is not rebuilt and no new absorption tower is added.The original absorption tower is reinforced.The flow of the original oxidation fan cannot meet the requirements.One Roots oxidation fan is added to each desul⁃furization oxidation wind system.Working principle:total resistance of desulfurization system is not more than 2700 Pa(resistance between inlet expansion joint of absorber and outlet expansion joint of absorber).The high efficiency desulfurization device in the tower is used in the reconstruction project of the desulfurization system,and the desulfurization efficiency is more than 99%.The inlet dust content of the desulfurization system reconstruction project is 35 mg/m^(3),and the outlet dust content is less than 20 mg/m^(3).The high-efficiency mist eliminator(one-layer tube mist eliminator+two-layer ridge mist eliminator)was used in the desulfurization system reconstruction project,and the droplet content at the desulfurization outlet was less than 40 mg/m^(3).After the transformation,the desulfurization system of 1000 MW unit has carried out experimental research on relevant performance parameters.In the three working conditions of 1000 MW,800 MW and 400 MW,the desulfurization efficiency,process water consumption,limestone consumption,power consumption,gypsum quality,net flue gas droplet content,SO_(2)import and export,and net flue gas dust concentration are tested.The test results show that the test indexes can meet the design performance guarantee value.The retrofit unit has completed ultra-low emission retrofit and has been put into operation for three years.On the whole,the FGD system equipment runs well,and the emission indicators have reached the"50,35,10"ultra-clean target.The measured emission data are far below the annual total emission reduction control target.