Determination of emission factor of creteria air pollutant from indegenous earth mound kiln charcoal production.
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Date
2015
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Obafemi Awolowo University
Abstract
This study was designed to fabricate an indigenous earth mound kiln and single drum kiln for traditional charcoal production. The gaseous emissions from the earth mound and single drum kiln were characterized for criteria air pollutants, and the emission factors of the criteria air pollutants identified in the earth mound and single drum kiln were determined.
The earth mound kiln was prepared using the indigenous design which involves an array of the wood placed horizontally on a cleared ground surface, and covered with a layer of grass, leaves and soil. The single drum kiln was constructed using a (90cm length x 54cm diameter) metallic drum fabricated with a top chimney using an existing design parameter. Two species of hardwood: Neem hardwood (Azadirachta indica) and Jumbay hardwood (Laucaena leucocephala) with pre-determined moisture content were used as carbonization raw material in both kilns. Once carbonization was initiated in the kilns, gaseous emissions from the carbonization process were characterized for criteria air pollutants including CO, NOx, HC, H2S, and SO2 using the E8500 industrial flue gas and combustion analyser in both the earth mound and single drum kilns. The emission factor of the criteria air pollutants investigated during the carbonization process was determined using the carbon balance method and reported on the basis of wet wood used, dry wood used, and charcoal produced. The results obtained from characterization of these pollutants were compared to that of available limits for stationary source emissions for characterized gaseous pollutants by the Federal Environmental Protection Agency (FEPA) being the only available standard for verifying source emissions in the country, while the emission factor was compared with that reported by EPA’s emission factor documentation for AP-42.
A moisture content value of 0.17 (g/g) was derived for the wood species investigated, which was used in calculating the emission factor of the characterized pollutants on dry wood basis. The earth mound kiln showed a high emission factor of 0.51 (g/kg) for CO and low factor of 9.38E-04 (g/kg) for H2S on basis of wet wood used, while a high emission factor of 0.59 (g/kg) for CO and low factor of 4.27E-03 (g/kg) for SO2 was observed on basis of dry wood used, and a high emission factor of 3.93 (g/kg) for HC and a low factor of 7.65E-03 for H2S was reported on basis of charcoal produced. The single drum kiln showed a high emission factor of 0.59 (g/kg) for CO and low factor of 9.46E-04 (g/kg) for H2S on basis of wet wood used, while a high emission factor of 0.69 (g/kg) for CO and low factor of 4.54E-03 (g/kg) for NOx was observed on basis of dry wood used, and a high emission factor of 6.65 (g/kg) for CO and low factor of 0.01 (g/kg) was reported on basis of charcoal produced. Comparing the results of the characterized pollutants with that of standard showed that the concentration of CO measured from both kilns exceeded the permissive limits, while the concentration of HC exceeded the permissive limits only in the earth mound kiln. The emission factor derived in the present study on comparing to that of previous work by EPA’s emission factor documentation for AP-42 was observed to fall within permissible limits, and deviations observed were attributed to difference in the raw material used, kiln design type, and operating conditions.
In conclusion, traditional methods of charcoal production is susceptible to emission of criteria air pollutants which could affect ambient air quality. Introduction of recovery units and use of more localised emission sampling methods were recommended.
Description
xiv,100 p.
Keywords
Emission Factors, Air Pollutants, Indigenous Earth, Mound Kiln Charcoal Production, Federal Environmental Protection Agency
Citation
Adeyi,T.T.(2015).Determination of emission factor of creteria air pollutant from indegenous earth mound kiln charcoal production.Obafemi Awolowo University.