低低温电除尘器设计烟温的理论计算及存在问题

The Theoretical Calculation of Designed Temperature of Flue Gas in Low-Low Temperature Electrostatic Precipitator and the Existing Problems

与常规电除尘器相比,低低温电除尘器在节能和环保方面有一定优势。对其实际运行案例进行汇总,并分析了国内外低低温电除尘器的设计烟温差异。酸露点的正确估算对低低温电除尘器烟温设计至关重要,以某电厂600 MW低硫煤燃煤机组为研究对象,采用3种广泛使用的酸露点计算方法,对烟气酸露点温度进行预测,并分析了各方法所得结果的准确性及可能存在的问题。同时,通过计算烟气中粉煤灰与SO_3质量浓度之比,评价该电厂采用低低温电除尘技术后的设备腐蚀隐患,分析低低温电除尘技术的可用性。对低低温电除尘器入口烟温设计范围提出建议,并分析低低温电除尘器入口烟温长期高于酸露点温度运行的弊端。

Compared with the traditional electrostatic precipitator, the low-low temperature electrostatic precipitator（LLT-ESP） has some advantages in the aspects of energy conservation and environmental protection. This paper conducts a study on the practical application cases of LLT-ESP both at home and abroad, analyzing the differences of their designed flue gas temperatures. The conclusion is that the correct estimate of the gas acid dew-point is crucial for the temperature designing of LLT-ESP. Taking a typical 600-MW coal-fired power plant for example, three widely-used methods are adopted to calculate the acid dew-point with the corresponding accuracy and possible problems being analyzed. In addition, the D/S ratio is calculated to evaluate the device corrosion potential and the feasibility of LLT-ESP. At the end, suggestions on the temperature design of LLT-ESP are proposed, and the possible problems in the LLT-ESP operation when the flue gas temperature being long-term higher than the acid dew point. are analyzed.