Abstract
Domestic combustion of solid fuels is, besides traffic and industry, a major source to particles in the air. Increased biomass combustion means a risk of contributing to high concentrations of particles with respect to the environmental goals. Particles are a health risk. The number of ultrafines and the content of the particles are considered crucial for the effects. Gradually, new solid biofuels with high ash content and different ash composition are used. This means an enhanced risk of high particle emission and a change in the formation of particles. The aim of the project is to contribute to the description of the mechanisms for formation of particles at combustion of biomass with high content of ash. The possibility to decrease the particle emission by the use of additives will be especially investigated. Thereby, problems with particle emissions, as well as formation of deposits may be minimized. The project contains two parts. The first one is about combustion of oat grain, and has already been reported. In this report the second part of the project is presented. Reed canary grass and straw were studied. To decrease the particle emission from combustion of straw, tests with straw and the additive kaolin (clay
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Citation Formats
Baefver, Linda, and Ryde, Daniel.
Particles from combustion of fuel with high content of ash - Experimental study of reed canary grass and straw; Partiklar fraan foerbraenning av askrika braenslen - Experimentell studie paa roerflen och halm.
Sweden: N. p.,
2010.
Web.
Baefver, Linda, & Ryde, Daniel.
Particles from combustion of fuel with high content of ash - Experimental study of reed canary grass and straw; Partiklar fraan foerbraenning av askrika braenslen - Experimentell studie paa roerflen och halm.
Sweden.
Baefver, Linda, and Ryde, Daniel.
2010.
"Particles from combustion of fuel with high content of ash - Experimental study of reed canary grass and straw; Partiklar fraan foerbraenning av askrika braenslen - Experimentell studie paa roerflen och halm."
Sweden.
@misc{etde_1004313,
title = {Particles from combustion of fuel with high content of ash - Experimental study of reed canary grass and straw; Partiklar fraan foerbraenning av askrika braenslen - Experimentell studie paa roerflen och halm}
author = {Baefver, Linda, and Ryde, Daniel}
abstractNote = {Domestic combustion of solid fuels is, besides traffic and industry, a major source to particles in the air. Increased biomass combustion means a risk of contributing to high concentrations of particles with respect to the environmental goals. Particles are a health risk. The number of ultrafines and the content of the particles are considered crucial for the effects. Gradually, new solid biofuels with high ash content and different ash composition are used. This means an enhanced risk of high particle emission and a change in the formation of particles. The aim of the project is to contribute to the description of the mechanisms for formation of particles at combustion of biomass with high content of ash. The possibility to decrease the particle emission by the use of additives will be especially investigated. Thereby, problems with particle emissions, as well as formation of deposits may be minimized. The project contains two parts. The first one is about combustion of oat grain, and has already been reported. In this report the second part of the project is presented. Reed canary grass and straw were studied. To decrease the particle emission from combustion of straw, tests with straw and the additive kaolin (clay mineral) were also carried out. The fuels were pelletized and contained 4-5 % ash (dry fuel). Reed canary grass (perennial grass) was chosen because it is has potential and it has also been much studied in Sweden. Straw was chosen because it has high accessibility, and is already fired to a certain degree. Straw contained 2.6 times more chlorine than reed canary grass. Reed canary grass had Si as dominating ash element (79 %), and thereafter it contained K (6 %), Ca (6 %) and P (3 %). A good half of the straw ash contained Si and thereafter K (23 %) and Ca (15 %) were most abundant. The fuels were continuously fired in a multi-stoker from Sonnys Maskiner, connected to a boiler from Centrometal. The particles mass concentration was measured by sampling on filter, and the mass size distribution with a low pressure impactor (LPI). The foil samples from the LPI were chemically analysed. The number concentration and size distribution were measured with an electrical LPI. Combustion of reed canary grass led to the lowest concentrations of particles, both with respect to mass, 12 mg/MJ, and number, 8.2 x 1012/MJ. Mass concentration at straw combustion was 64 mg/MJ, and the number concentration was 14 x 1012/MJ. The case of 3 % kaolin mixed with the straw pellets gave a decrease of the mass concentration, but simultaneously the emission almost doubled with respect to number of particles. However, in the case straw and 6 % kaolin the mass concentration of particles increased, while about the same number concentration as in the other additive case was noted. The following conclusions are drawn from this work: - Pellets from reed canary grass were good to fire in the multi-stoker used. However, the effects of ash in the long-range needs to be further investigated. - It is, because of slagging, not recommended to fire straw pellets in the stoker. - Combustion of straw pellets and the additive kaolin works fine in the stoker. - Combustion of reed canary grass gave very low emission of particles (mass). Mainly fine (< 1mum) particles, dominated by potassium sulphate, were emitted. - Combustion of straw gave much higher emission of particles than combustion of reed canary grass. The particles were mainly fine and dominated by KCl. - The number concentration of particles was almost twice as high at combustion of straw as it was at combustion of reed canary grass. Fine particles dominated. - High content of ash in the fuel combined with high content of chlorine and potassium means a risk of high particle emission. - There is a potential of decreasing the emission of particles by adding kaolin to straw fuel. However, there is a risk of overdosing and thus enhance the emission}
place = {Sweden}
year = {2010}
month = {Jul}
}
title = {Particles from combustion of fuel with high content of ash - Experimental study of reed canary grass and straw; Partiklar fraan foerbraenning av askrika braenslen - Experimentell studie paa roerflen och halm}
author = {Baefver, Linda, and Ryde, Daniel}
abstractNote = {Domestic combustion of solid fuels is, besides traffic and industry, a major source to particles in the air. Increased biomass combustion means a risk of contributing to high concentrations of particles with respect to the environmental goals. Particles are a health risk. The number of ultrafines and the content of the particles are considered crucial for the effects. Gradually, new solid biofuels with high ash content and different ash composition are used. This means an enhanced risk of high particle emission and a change in the formation of particles. The aim of the project is to contribute to the description of the mechanisms for formation of particles at combustion of biomass with high content of ash. The possibility to decrease the particle emission by the use of additives will be especially investigated. Thereby, problems with particle emissions, as well as formation of deposits may be minimized. The project contains two parts. The first one is about combustion of oat grain, and has already been reported. In this report the second part of the project is presented. Reed canary grass and straw were studied. To decrease the particle emission from combustion of straw, tests with straw and the additive kaolin (clay mineral) were also carried out. The fuels were pelletized and contained 4-5 % ash (dry fuel). Reed canary grass (perennial grass) was chosen because it is has potential and it has also been much studied in Sweden. Straw was chosen because it has high accessibility, and is already fired to a certain degree. Straw contained 2.6 times more chlorine than reed canary grass. Reed canary grass had Si as dominating ash element (79 %), and thereafter it contained K (6 %), Ca (6 %) and P (3 %). A good half of the straw ash contained Si and thereafter K (23 %) and Ca (15 %) were most abundant. The fuels were continuously fired in a multi-stoker from Sonnys Maskiner, connected to a boiler from Centrometal. The particles mass concentration was measured by sampling on filter, and the mass size distribution with a low pressure impactor (LPI). The foil samples from the LPI were chemically analysed. The number concentration and size distribution were measured with an electrical LPI. Combustion of reed canary grass led to the lowest concentrations of particles, both with respect to mass, 12 mg/MJ, and number, 8.2 x 1012/MJ. Mass concentration at straw combustion was 64 mg/MJ, and the number concentration was 14 x 1012/MJ. The case of 3 % kaolin mixed with the straw pellets gave a decrease of the mass concentration, but simultaneously the emission almost doubled with respect to number of particles. However, in the case straw and 6 % kaolin the mass concentration of particles increased, while about the same number concentration as in the other additive case was noted. The following conclusions are drawn from this work: - Pellets from reed canary grass were good to fire in the multi-stoker used. However, the effects of ash in the long-range needs to be further investigated. - It is, because of slagging, not recommended to fire straw pellets in the stoker. - Combustion of straw pellets and the additive kaolin works fine in the stoker. - Combustion of reed canary grass gave very low emission of particles (mass). Mainly fine (< 1mum) particles, dominated by potassium sulphate, were emitted. - Combustion of straw gave much higher emission of particles than combustion of reed canary grass. The particles were mainly fine and dominated by KCl. - The number concentration of particles was almost twice as high at combustion of straw as it was at combustion of reed canary grass. Fine particles dominated. - High content of ash in the fuel combined with high content of chlorine and potassium means a risk of high particle emission. - There is a potential of decreasing the emission of particles by adding kaolin to straw fuel. However, there is a risk of overdosing and thus enhance the emission}
place = {Sweden}
year = {2010}
month = {Jul}
}