State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China.
Sci Total Environ. 2019 Apr 20;662:455-461. doi: 10.1016/j.scitotenv.2019.01.080. Epub 2019 Jan 22.
The performance of traditional electrostatic precipitators (ESPs) is strongly affected by the flue gas temperature. Operating under much lower temperatures (e.g., ~90 °C), the low-low temperature electrostatic precipitators (LLT-ESPs) are considered as an effective technology to improve the particulate matter (PM) removal efficiency in coal-fired power plants (CFPPs). Wet flue gas desulfurization (WFGD) can also be affected by the decrease in the operating temperature of the ESP. This study evaluates the influence of various ESP operating temperatures on ESP performance, PM (particles with an aerodynamic diameter of ≤2.5 μm), and total dust emission characteristics at the ESP and WFGD outlets in CFPPs equipped with LLT-ESPs. PM and total dust concentrations at the ESP and WFGD outlets in CFPPs installed with LLT-ESPs are much lower than those with traditional ESPs. The PM concentrations at both the ESP and WFGD outlets show a decreasing trend with a decrease in the operating temperature. However, the concentration of total water-soluble ions (mainly SO, Cl, and NH) in the total dust at the outlet of ESPs increases from 0.3 to 0.8 mg/m as the temperature decreases from > 90 °C to 80-90 °C, which is contrary to that at the WFGD outlet (decreases from 4.7 to 0.8 mg/m). The PM and total dust concentrations increase by 10.2-80.2% and 13.7-77.0%, respectively, through the WFGD unit due to the entrainment of a gypsum slurry. A relatively lower operating temperature of LLT-ESPs in power plants is also beneficial to decrease the incremental effect of PM emissions in the process of WFGD. The recommended operating temperature for LLT-ESPs is ~90 °C, and limited improvement on PM reduction can be achieved with a further temperature decrease from 90 to 80 °C.
传统静电除尘器（ESP）的性能受烟气温度的强烈影响。在低得多的温度下运行（例如，~90°C），低温静电除尘器（LLT-ESP）被认为是提高燃煤电厂（CFPP）中颗粒物（PM）去除效率的有效技术。湿法烟气脱硫（WFGD）也会受到 ESP 运行温度降低的影响。本研究评估了各种 ESP 运行温度对 LLT-ESP 配备的 CFPP 中 ESP 性能、PM（空气动力学直径≤2.5μm 的颗粒）和 ESP 及 WFGD 出口处总粉尘排放特性的影响。配备 LLT-ESP 的 CFPP 中 ESP 和 WFGD 出口处的 PM 和总粉尘浓度远低于配备传统 ESP 的 CFPP。随着操作温度的降低，ESP 和 WFGD 出口处的 PM 浓度呈下降趋势。然而，ESP 出口处总粉尘中总水溶性离子（主要为 SO、Cl 和 NH）的浓度从>90°C 降低到 80-90°C时从 0.3 增加到 0.8mg/m，这与 WFGD 出口处的情况相反（从 4.7 降低到 0.8mg/m）。由于石膏浆液夹带，通过 WFGD 单元，PM 和总粉尘浓度分别增加了 10.2-80.2%和 13.7-77.0%。由于 WFGD 过程中 PM 排放的增量效应降低，工厂中 LLT-ESP 的相对较低的操作温度也有利于减少 PM 排放。推荐的 LLT-ESP 操作温度约为 90°C，从 90°C 进一步降低温度至 80°C，对 PM 减排的效果有限。
