![]() A prototype of pulse power supply has been installed on the electrostatic precipitator of a coal burning 320 MWe thermal unit and some tests have been carried out to verify its performance with different operating conditions. In order to avoid such a behaviour, a different kind of energization, based on the superposition of narrow voltage pulses to a DC voltage, may be used. Mattachini, F.Įlectrostatic precipitators performances are greatly influenced by the physical and chemical characteristics of the particles which are to be collected a very important role is played by electric resistivity of fly ash: when it is high we have a general increase in the number of discharges within the precipitator ,with a consequent decrease in collection efficiency and an increase in emissions. Improvement of the performance of the electrostatic precipitators for coal thermal power plantsĮnergy Technology Data Exchange (ETDEWEB)īaldacci, A. ![]() The comparison shows that it is necessary to optimise the discharge electrode construction for a specific physico-chemical property of fly ash so as to obtain the highest collection efficiency. The results of the collection efficiency measurements in these tests were compared with those obtained from an ordinary industrial ESP. The aim of the tests was to determine the current-voltage characteristics and the discharge current distribution on the collection electrode so as to find out the optimal construction and ensure the maximal collection efficiency of ESP. Four constructions of discharge electrode were tested for fly ash of different fractional sizes and chemical compositions. The main dimensions of the precipitator chamber were as follows: length of electric field 2.0 m active height 0.45 m and spacing between the collecting electrodes 0.4 m. In these studies a test bench was constructed, which comprised one-stage model ESPs with a set of discharge and collecting electrodes. The objective of the model studies in this paper was to select the optimal construction of the discharge electrode in ESP for obtaining high collection efficiency of fly ash leaving stoker boilers. International Nuclear Information System (INIS)ĭue to increasing restrictions on dust emission limits (IED directive), particularly in the fine particle size range, wider application of electrostatic precipitators (ESPs) in cleaning the combustion gases from stoker boilers can be anticipated. All rights reserved.Ĭollection of low resistivity fly ash in an electrostatic precipitator The separation of the finer fractions (ESP 2 and 3) from ESP 1 field fly ash is recommended. Overall, the results of this study suggest that it is possible to improve the utilization potential of fly ashes from fluidized bed combustion in concrete, fertilizer, and earth construction applications by using electrostatic precipitators for the fractionating of fly ashes in addition to their initial function of collecting fly ash particles from flue gases. Results showed that all fly ashes behaved similarly in the electrostatic separation process SiO 2 resulted in coarse fractions with Nelson's selectivity of 0.2 or more, while sulfate, chloride, and the studied detrimental metals (arsenic, cadmium, and lead) enriched into fine fractions with varying selectivity from 0.2 to 0.65. Classification selectivity calculations of electrostatic precipitators for three different fuel mixtures from two different power plants were performed by using Nelson's and Karnis's selectivity indices. This study aimed to establish whether the utilization of fly ash from the fluidized bed combustion of peat, wood, and forest residues can be improved by electrostatic precipitator separation of sulfate, chloride, and some detrimental metals. Therefore, there is a great interest in utilizing fly ashes instead of just disposing of it. The increasing use of biomasses in the production of electricity and heat results in an increased amount of burning residue, fly ash which disposal is becoming more and more restricted and expensive. ![]() Ohenoja, Katja Körkkö, Mika Wigren, Valter Österbacka, Jan Illikainen, Mirja Fly ash classification efficiency of electrostatic precipitators in fluidized bed combustion of peat, wood, and forest residues. ![]()
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