Combustion of pellets from wheat straw (RCG) from Finland, pellets made of apple juice industrial...
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Acta Montanistica Slovaca Ročník 17 (2012), číslo 4, 283-289
Combustion of pellets from wheat straw
Jozef Jandačka, Michal Holubčík, Štefan Papučík and Radovan Nosek1
The alternative energy sources are more and more used for production of heat. Several new combustion devices allow co-firing of different fuels, like dendromass and phytomass. The article analyses combustion of wood and straw pellets in the same boiler. Measurements were realized in two automatic heat sources – one is adapted to burn pellets made from wood or straw and another allows only burning of wood pellets. There are analysed performance and emission parameters of boiler. Key words: wood pellets, straw pellets, energy crops, performance, emission
At present there is high interest in using of agricultural waste from plant production and energy using of energy crops that are deliberately planted on a big fields. Energy crops are plants with non-wood stems grown specifically for energy production. Their energy content is about 15 - 20 MJ.kg-1 in the dry state. Growing of energy crops has an indisputable advantage for farmers because they do not compete with food, so this "green energy" can then ensure smooth sales.
In terms of Europe can plant create 1.2 to 1.4 g of dry phytomass from 1 MJ of solar power, plant with C4 type of photosynthesis are more efficient. Creation of 1.4 g dry weight from 1 MJ of solar energy is considered one of the criteria for selection of plants for use in phytoenergetics. (Jandačka et al., 2007)
These energy crops can be directly used for production of heat in combustion devices or they can be improved to pellets or briquettes.
In practice, there are used only a few kinds of plants. In terms of energy is particularly important yield, production costs, product modification for the purpose of heating engineering, logistics, transport of finished biofuel to consumers, etc. Grown plants, bio-treatment, distribution and marketing of agricultural biofuels are aspects for the use of plants. Energy content of agricultural biofuels for energy using is necessary to utilize in combustion devices, and this is the second page of the problem.
Most agricultural biofuels have low temperature point of softening, melting and flow of ash (cereal straw) or a large production of CO (carbon monoxide) (feeding juices and most types of grass) and almost all contain a high content of ash (more than 5 %). These are negative qualities that wood biomass pellets and briquettes from waste wood do not have. One of the ways to eliminate negative properties is making from energy crops and other possible components a mixture of certain proportions. Another option to eliminate negative properties of agricultural biofuel combustion is adjusting of combustion device such another type of burner, shape and size of combustion chamber, rapping and blowing of burner to remove the excessive proportion of ash, or modification of regulatory and management system. (Jandačka et al., 2007).
In many cases, manufacturers of automatic boilers for wood pellets report that in these boilers can be burnt pellets made from energy crops (straw pellets) as well. These small heat sources are produced in most cases, with automatic control using regulation of feeding and standing time. In feeding time is fuel transported by screw conveyor to burner in combustion chamber. However, for each fuel type is this setting various and the biggest problem for manufacturers of boilers is finding usable interval of fuel feeding. It is given by different properties of used fuel. It is also important to note that change of settings which control to lower operating performance (lower time intervals) may not be automatically provided setting to optimum combustion of fuel. It is necessary to do a lot of experiments in order to find usable time intervals for combustion of various types of fuel in one heat source.
Verma et al. (2011) tested wood pellets from the Belgium, peat pellets and reed canary grass pellets
(RCG) from Finland, pellets made of apple juice industrial waste from Poland, pectin pellets made of citrus shell (CPW) from Denmark, sunflower husk pellets (SFH) from Ukraine and two kinds of wheat straw pellets from Belgium (straw-1 with 100% pure straw and straw-2 with 2wt% of hydrated lime [Ca(OH)2] 1 prof. Ing. Jozef Jandačka, PhD., Ing. Michal Holubčík, Ing. Štefan Papučík, PhD., Ing. Radovan Nosek, PhD., Department of power
engineering, Faculty of Mechanical Engineering, University of Zilina, Univerzitná 8215/1, 010 26 Žilina, tel. +421 (0)41 513 2851, firstname.lastname@example.org , email@example.com , firstname.lastname@example.org , email@example.com
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tomatically fi g m−3 (STP, 1 tems account
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h movable com ws the basic op d individual fu .
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n average arou rous sugar w nerally, emiss consisting of full load or p
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For agro-pelle ng temperatur pple pellets ha life condition atory performa onditions; how ndition, dust e xamination o sub-micron siz aseous emissi ally and 2 ma as further bio
pellets were a dilution sys e emissions r of replicate e
m−3 (standard c Wood pellets an most one ord mg MJ−1. Aro d 30–40 % fo
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Emissions are type. Surprisin 466 mg m−3 ( h chlorine an
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omatic biomas and wood chip . Combustion
placed control gh which thes ominal perfor
ner of boiler “1”.
standard labo stan