燃煤机组SCR脱硝系统近零排放下热工控制研究与工程实践

Thermal Control Investigation and Engineering Practice of an SCR Denitration System in Near-zero Emission Coal-fired Units

针对某燃煤电厂进行"近零排放"改造后,SCR脱硝系统无法实现长时间稳定的NO_x排放的现状,从热工控制逻辑着手进行研究,并进行工程应用,提出了适合"近零排放"改造后SCR脱硝系统热工控制的关键技术.结果表明:通过NO_x生成端优化,机组NO_x平均质量浓度进一步降低,基本控制在200mg/m^3;在原有的前馈-反馈串级控制基础上引入智能预测前馈控制,有效地进行偏差调节;烟囱出口NO_x质量浓度超过50mg/m^3的时间进一步减至0.

To solve the problem existing in a certain coal-fired thermal power plant that its SCR denitrification system was unable to keep long-term stable NOx emission after near-zero emission retrofit, an investigation was conducted on the thermal control logic, and subsequently key thermal control technologies were proposed for the SCR denitrification system, which were then put into engineering application. Results show that the average NO, concentration of unit could be reduced to below 200 mg/ma through optimization on the generation process of NO~ ~ effective deviation adjustment could be fulfilled by introducing intelligent predictive feedforward control to the original feedforward-feedback cascade control; the emission concentration of NOx from the funnel could be reduced to below 50 mg/m^3