Size Distribution of Fine Particle Emissions from a Steam Plant with a Fluidized-Bed Coal Combustor

Abstract

The size distribution of fly ash emitted from an atmospheric fluidized-bed coal combustor (AFBC) with a 20-mZ croswection bed equipped with cyclones and a baghouse system to control the particulate emission is described. The Georgetown AFBC was designed to produce a maximum of 100,000 pounds/h of saturated steam at 275 or 625 psig to support space heating and to supply hot water to the university. A 2-cyclone dust collector was used to remove large fly ash particles from the effluent stream, and a baghouse system was used for fine control of the particulate emissions before discharging to the atmosphere. The fly ash concentration and size distribution before and after the baghouse dust control system were measured, and the collection efficiency of the baghouse system was determined. A bimodal size distribution of fly ash was observed. The mass fraction of submicron particles was 4.3% before the haghouse and increased to 18% at the stack because the collection efficiency of the baghouse was size dependent. The high collection efficiency (99.98%) of the newly installed baghouse removed most of the fly ash; therefore, the emission factor for particles was below the new source performance standards required, by the EPA. Comparison of fly ash size distributions obtained in several fluid-bed coal combustors are discussed.

Expansion of a size disaggregation profile library for particulate matter emissions processing from three generic profiles to 36 source-type-specific profiles

“…Summary of literature studies used for PM size distribution analysis for different PM emissions source types (see Table S1 for key to abbreviations). penetration (%) versus particle size were obtained from two literature studies (Benítez 1993;Cheng et al 1985). These plots were digitized as described above, and the average penetration fraction for particles within each size bin range was calculated.…”

Size Distributions, Microstructures, and Elemental Compositions of PM2.5 from Two Coal-Fired Fluidized-Bed Boilers Equipped with Fabric Filters

“…The research results of Shendrikar et al showed that the particle size distributions (PSDs) of most elements before going through the FFs, in which several PCBs were equipped with, were bimodal, which had the higher peaks at approximately 4–10 μm and the lower peaks at approximately 0.08 μm or less. Cheng et al investigated the number and mass size distributions of PM 10 generated from a small-scaled bubbling FB (BFB) boiler and found that the number size distribution of PM 10 generated from the BFB boiler was unimodal with a peak at <0.1 μm. Lind et al examined the number and mass size distributions, microstructures, and elementary compositions of PM 10 generated from a circulating FB (CFB) boiler combusting two types of coals, which was equipped with an ESP.…”

“…Lind et al examined the number and mass size distributions, microstructures, and elementary compositions of PM 10 generated from a circulating FB (CFB) boiler combusting two types of coals, which was equipped with an ESP. They compared the number size distribution of PM 10 generated from the CFB boiler with the number size distribution of PM 10 generated from the BFB boiler (Cheng et al), and found that the sub-micrometer peak of the number size distribution of PM 10 generated from the BFB boiler was 2 orders of magnitude higher than that generated from the CFB boiler. Besides, Bartocci et al pointed out that the mass concentration of particulate matters from charcoal during coal combustion is generally high than those during biomass combustion.…”

Field Measurements on the Emission and Removal of PM2.5 from Coal-Fired Power Stations: 2. Studies on Two 135 MW Circulating Fluidized Bed Boilers Respectively Equipped with an Electrostatic Precipitator and a Hybrid Electrostatic Filter Precipitator

“…As far as we know, the earliest known study characterizing the PM emitted from commercial scale fluidized bed (FB) coal combustion was carried out on atmospheric bubbling FB boilers with double fluidized beds (AFBC, 100000 poundswater/h) by Cheng et al in 1985, and it showed that the mass yield of fly ash in the FB boiler is close to that from the pulverized coal combustion (1.64−3.89 g/m 3 vs 2−10 g/m 3 ). 10 In a further study on a full-scale CFB boiler (80 MW) in 1996, the mass size distribution of PM generated from a low-sulfur bituminous coal combustion is determined with a Berner-type low-pressure impactor. 11 The results show that PM in the range 0.01−70 μm demonstrated unimodal mass size distribution and that the submicron PM is claimed to be generated via a combined mechanism of vaporization and melting of minerals in coal.…”