Comparative analysis of energy efficiency of electrostatic precipitator before and after ultralow emission in coal-fired power plants in China

Abstract

Electrostatic precipitator (ESP) is the main equipment for flue dust control of coal-fired power plants in China, accounting for about 70% of the total currently. In this paper, energy efficiency data of ESP, including 202 sets before ultra-low emission and 45 sets after ultra-low emission are systematically studied and analyzed by using the research method of field testing and technical investigation. The results showed that after ultra-low emission, the energy consumption and converted CO₂ emission of ESP in coal-fired power plants increased significantly, and the specific power consumption and energy consumption corresponding to unit mass particulate matter (PM) removal increased by 49.61% and 139%, respectively, and the converted CO₂ emission increased by 1.67 × 10⁻⁴ kg CO₂/m³ and 31.12 kg CO₂/t PM on average. The energy consumption of low-low-temperature ESP (LLT-ESP) was positively correlated with its emission reduction range. Before and after the gas cooler operation, the power consumption, specific power consumption and energy consumption corresponding to unit mass PM removal increased by 8.06%–38.68%, 10.66%–60.14% and 7.23%–62.98%, respectively, and the CO₂ emissions corresponded increased by 26.29–691.81 kg CO₂/h, 0.46–2.18×10⁻⁴ kg CO₂/m³, 1.10–23.62 kg CO₂/t PM, respectively. LLT-ESP had a great possibility to optimize the operation for energy-saving and carbon-reduction, because when the high voltage power supply operated on the maximum output mode and the energy-saving mode, the drop of power consumption and specific power consumption was around 52.00%–58.23%, 52.02%–58.29%, respectively, and the CO₂ emission reductions corresponded was 1,039.25–1,359.35 kg CO₂/h, 2.71–3.58×10⁻⁴ kg CO₂/m³, respectively. LLT-ESP also had the great optimizing possibility for energy-saving and carbon-reduction during low load operation, as when the load reduced from 100% to 50%, the specific power consumption and energy consumption corresponding to unit mass PM removal increased by 5.05%–45.50%, 6.59%–63.90%, respectively, and the CO₂ emissions corresponded increased by 0.38–2.44×10⁻⁴ kg CO₂/m³, 6.76–45.98 kg CO₂/h, respectively. The operation energy consumption can be effectively reduced by integrated use of multiple electric dust removal technologies, such as compared with LLT-ESP technology, the power consumption, specific power consumption and energy consumption corresponding to unit mass PM removal of “low-low-temperature + moving electrode+ electrostatic agglomeration” decreased by 37.88%, 30.08% and 45.29% respectively, and the corresponding CO₂ emission decreased by 697.22 kg CO₂/h, 1.87×10⁻⁴ kg CO₂/m³ and 32.98 kg CO₂/t PM, respectively. The current national standard GB 37484-2019 is no longer applicable to the energy efficiency evaluation of the ESP in ultra-low emission units. This study can provide data support for the revision of national standard GB 37484-2019 and the collaborative efficiency of coal power plant pollution reduction and carbon reduction. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.