Development of an online monitoring method for electrostatic precipitators on commercial biomass combustion plants

Abstract

AbstractCombustion plants based on wooden biomass as fuel can contribute to a decarbonization of the energy sector by reducing the need for fossil energy usage, which decreases the net carbon dioxide output in the atmosphere. However, the flue gas of biomass-based combustion plants contains increased amounts of particulate matter, which need to be separated before release into the environment because of legal emission limits. In medium-sized plants, electrostatic precipitators (ESP) are commonly used separators to minimize the particulate matter concentration. Due to new regulations based on the medium combustion plants directive introduced by the EU, continuous surveillance of secondary precipitation technologies like ESP has to be implemented. The method proposed in this paper focuses on the readily available current (I) and voltage (U) data of the high-voltage unit supply of an ESP to calculate the efficiency of the particle separation. Consequently, a continuous proof of function can be delivered without high cost for additional measurement equipment. This article proves the effectiveness of the method in calculating the precipitation effectiveness of the ESP. It is shown that the deviation from the separation efficiency calculated by the method and the measured efficiency is smaller than 7%. Additionally, it is necessary to define a suitable reference signal that indicates whether the combustion plant is running or not. Hence, the availability of the system can be evaluated. This method will help operators to meet legal requirements.