TY - JOUR AU - Nghishiyeleke, Eliaser T. AU - Kemba, Vallentinus M. AU - Endunde, Alexander M. S. AU - Mashingaidze, Melvin M. PY - 2020/10/20 Y2 - 2024/03/28 TI - Design of an electrostatic precipitator for a novel bituminous coal-fired circulating fluidised bed combustion power plant in Namibia JF - Journal of Energy in Southern Africa JA - J. energy South. Afr. VL - 31 IS - 3 SE - Articles DO - 10.17159/2413-3051/2020/v31i3a8752 UR - https://energyjournal.africa/article/view/8752 SP - 38-57 AB - <p>Coal-fired power plants utilising fluidised bed technologies emit copious amounts of fly-ash, which is harmful to people owing to its particulate nature. A planned 300&nbsp;MW power plant will have an electrostatic precipitator (ESP) for fly-ash emissions control, in line with power generation industry best practices. This ESP should meet a fly-ash emission limit value ≤&nbsp;50&nbsp;mg/Nm<sup>3</sup>. This paper details the design process and resultant technical specifications of a cold-side, single-stage, and plate-wire dry ESP designed for the power plant. The ESP will consist of twin-chambers with quadruple-fields (2 4 315&nbsp;m<sup>3</sup>) and octonary bus-sections independently energised by individual high-frequency three-phase switched integrated rectifiers (70&nbsp;kV,&nbsp;800&nbsp;mA) to maximise ionisation. Dynamically balanced, single-impact, tumbling hammer rappers (857.5&nbsp;rpm) will dislodge fly-ash from the collector plates into mass-flow wedge-shaped hoppers. A specific collection area (≥&nbsp;56.9&nbsp;m<sup>2</sup>/m<sup>3</sup>/s) and an ESP index&nbsp;(≥&nbsp;709.2&nbsp;(kV/cm)<sup>2</sup>m<sup>2</sup>/m<sup>3</sup>/s) should guarantee a collection efficiency (&nbsp; ≥&nbsp;99.5 %) and&nbsp;the specified emission limit value at 100 % boiler capacity and normal operating conditions (gas velocity&nbsp;≤&nbsp;2.4&nbsp;m/s; gas temperature&nbsp;≤&nbsp;137 ℃; fly-ash loading&nbsp;≤&nbsp;10&nbsp;000&nbsp;kg/Nm<sup>3</sup>; resistivity&nbsp;≤&nbsp;10<sup>10</sup>&nbsp;Ω‧cm). The design was successfully verified in principle using the validation square method, in conjunction with the leading comparable historical case studies approach. It is recommended to simulate ESP designs using suitable programs like Comsol Multiphysics and construct a pilot plant before attempting scaled-up construction and commissioning.</p><h2>Highlights&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</h2><ul><li>A cold-side, single-stage plate-wire dry ESP system designed.</li><li>Theoretical collection efficiency in excess of 99.5%.</li><li>High-frequency, three-phase switched integrated rectifiers to be used for ionisation.</li></ul> ER -