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This paper investigates the removal efficiency of a honeycomb electrostatic precipitator (ESP) applied to control particulate matter (PM) emissions from a small-scale boiler with combustion lignite and hard coal. The specifics of the precipitation of emissions from small-scale boilers are discussed, and the design principles for relevant ESPs are presented and used. The ion-induced nucleation of sulfuric acid occurred, causing the drastic penetration of 19 nm particles through the ESP. Despite this, the overall collection efficiency was sufficient to meet the EU's Ecodesign Directive requirements. Back corona was not detected. The optimal ESP performance is defined with further parameters: a current density of 0.5 mA/m2 at an electric field strength of about 2.7 × 105 V/m; a minimal specific collecting area of ESP (SCA) of 60 m2/(m3/s); and Nt-product of 4.5 × 1014 s/m3. Such parameters of ESPs should ensure adequate PM emissions control for any type of boiler with similar emissions characteristics. The composition of collected fly ash particles was analysed, and a method for fly ash utilisation was proposed. This research may be helpful for designing ESPs to control PM emissions for small-scale units with fossil fuel combustion. [ABSTRACT FROM AUTHOR]

In this study, 73 ash samples (comprising 49 ash samples from combustion tests performed in 2017, and 24 ash samples from combustion tests performed during 2014–2016 at the Energy Research Center, Ostrava, Czech Republic) were analysed. Ash samples were obtained via the combustion of various solid fuels, their mixtures with municipal waste (floor coverings, paper, polyethylene terephthalate (PET) briquettes, plastics, and textiles), and municipal wood waste (furniture chipboard, window frames) in household combustion units, such as an overfire boiler, boiler with downdraft combustion, gasification boiler, automatic boiler, and stove. The aim of this study was to determine the composition of representative ash samples from solid fuels and municipal waste and to determine which parameters (metals and halides) were present in the ash analysis after waste incineration. Statistical evaluation of box plots with the determination of the boundaries for outliers and extreme values was performed. Finally, six metals (Sb, Cu, Pb, Sn, Ti, and Zn), together with chlorides, were taken as the indicators of municipal waste incineration in households. The highest value of Sb was 344 mg/kg in plastics + dry beech; the highest value of Cu was 30,500 mg/kg in textiles + black coal (B1); the highest concentration of Pb was 1,360 mg/kg in floor coverings + dry beech; the highest value of Sn was 108 mg/kg in textiles + dry beech; the highest concentration of Ti was 38,200 mg/kg in window frames; the highest value of Zn was 215,000 mg/kg in window frames; and the highest concentration of chlorides was 191,000 mg/kg in floor coverings + dry beech. • 73 ash samples from the combustion units used in households were analyzed. • The combustion of municipal waste is a problem in residential boilers and stoves. • Three types of solid fuels and seven types of municipal waste were combusted. • Heavy metals and chlorides were compared. • Sb, Cu, Pb, Sn, Ti, Zn, Cl were chosen as indicators of municipal waste combustion. [ABSTRACT FROM AUTHOR]

• Particles from small-scale combustion require a suitable charging model. • Some charging models are used to predict the ESP efficiency. • The optimal charging model is selected and confirmed by practical measurement. • The selected charging model is useful for practical engineering. The present study investigates methods for predicting the efficiency of electrostatic precipitation for controlling particulate matter (PM) emissions from small-scale heating units, namely, solid fuel combustion boilers with heating power output less than 300 kW. The prediction correctness for particle precipitation efficiency is considered on the basis of the accuracy of the estimated charge on a particle. Prediction of the specific PM from small-scale boilers requires a relevant model of specified particle charging. Three appropriate particle charge models have been used to predict the efficiency of a specific electrostatic precipitator (ESP). The prediction results are compared on the basis of experimental measurements taken from an ESP used to control the emissions from a 160-kW boiler. The measurements are based on different physical principles and are undertaken simultaneously. The optimal method for particle charge evaluation is determined to allow the practical modeling of an ESP to control the PM emissions from small-scale units with solid fuel combustion. [ABSTRACT FROM AUTHOR]

• Particles from small-scale combustion require a suitable charging model. • Sole field or diffusion charging mechanisms are unsuitable for such particles. • The summation of these mechanisms leads to inaccurate prediction of ESP efficiency. • Some available charging models are analysed, and the most suitable are selected. Small-scale heating units with solid fuels combustion cause a global atmospheric pollution by fine particles. Electrostatic precipitation is suggested as a method of controlling fine particle emissions. The correctness of modelling for precipitation efficiency is defined by the accuracy of the evaluation of particle charges. This work focuses on reviewing the existing particle charging theories in terms of their suitability for practical engineering for the electrostatic precipitation of fly ash particles from the flue gases of small-scale boilers. Charging calculation methods were rated as a function of the particle sizes, external discharge electric field strength, and ion density-time product and compared to published experimental data. Two particle charge rating methods were identified to be suitable for the electrostatic precipitation of such particles. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the use of an electrostatic precipitator (ESP) for controlling the emissions of particulate matter (PM) from small-scale heating units, specifically boilers that combust solid fuel with a heating power output of <300 kW. The equilibrium between the required precipitation efficiency and the structural parameters of the ESP in combination with the applied voltage were determined. This study presents a method of optimising the applied voltage alongside the specific ESP structural parameters while retaining the required precipitation efficiency. The ESP was designed, optimised, and integrated into a 15-kW boiler without expanding its volume. The theoretically predicted voltages and resulting ESP efficiency (20 kV and 85% respectively) were verified by measuring the reduction in the particle number concentration. The measurements were based on different principles and simultaneously sampled. The PM concentrations were reduced below 40 mg/m3 (0 °C, 101.3 kPa; at reference O 2 = 10 % vol.) by nominal and reducing the heat power, which allowed the boiler to meet the requirements of the EU's Ecodesign Directive. The presented optimisation method can be used in the practical engineering of any type of ESP. • An ESP was encased in a 15-kW automatic boiler's body as an inseparable part. • The boiler thereby met the EU's Ecodesign Directive emissions requirements. • An optimisation method was proposed to ensure the ESP's required efficiency. • Two-type numeric concentration measurements verified this method. • The method is useful for assessing the structural potential of any ESP. [ABSTRACT FROM AUTHOR]