Combustion of pellets from wheat straw · (RCG) from Finland, pellets made of apple juice...

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Acta Montanistica Slovaca Ročník 17 (2012), číslo 4, 283-289 283 Combustion of pellets from wheat straw Jozef Jandačka, Michal Holubčík, Štefan Papučík and Radovan Nosek 1 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 Introduction 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. Related work 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, [email protected] , [email protected] , [email protected] , [email protected]

Transcript of Combustion of pellets from wheat straw · (RCG) from Finland, pellets made of apple juice...

Page 1: Combustion of pellets from wheat straw · (RCG) from Finland, pellets made of apple juice industrial waste from Poland, pectin pellets made of citrus shell (CPW) from Denmark, sunflower

Acta Montanistica Slovaca Ročník 17 (2012), číslo 4, 283-289

283

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

Introduction

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.

Related work

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, [email protected] , [email protected] , [email protected] , [email protected]

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Jozef Jand

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Jozef Jand

286

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Page 5: Combustion of pellets from wheat straw · (RCG) from Finland, pellets made of apple juice industrial waste from Poland, pectin pellets made of citrus shell (CPW) from Denmark, sunflower

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o 4, 283-289

287

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Jozef Jand

288

of burnerclusters oprocess.

Ave1214 mgof straw pand emiss

AveAverage of combupellets inand emisscontinuedand unbuand therm

It is or burnerwas morperformadesigned of pellets

ačka, Michal Ho

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F

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to burn only s, this differen

olubčík, Štefan P

t adapted for bcaused low f

Fig. 10. Pr

Fig. 11. Profiles

performance Ox 186 mg.m-

ler “1” was 13676 mg.m-3 of

ed thermal peoduction of ed pellets in bowas 8,9 kW644,3 mg.m-

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wood pelletsnce was 33.7 %

Papučík and Rad

burning of agflow temperatu

rofiles of thermal

of measured emi

C

of boiler “1” -3 in boiler “13,2 kW. Averf combustion

erformance ofemission CO oiler “2”. Ave

W. Average m-3 of combustecreased, becash box. Latey.

of straw biomabeen shown o

tion in boileran in the case s, namely 43.3%.

dovan Nosek: Co

gricultural pellure of ash. Th

l performance – b

issions CO and N

Conclusion

was 19,9 kW1”. Average mage measuredof straw pelle

f combustion was 1034,4

rage measuremeasured prodtion of straw cause clusterser, after mea

ass is complicon measuremer “2”. Duringof wood pell

3 %. The boil

ombustion of pelle

lets. On the suhese ash clust

boiler “2”, straw

NOx – boiler “2”,

W. Average memeasured therd production oets in boiler “1

of wood pellmg.m-3 and ed thermal per

duction of empellets in boi

s of ash limsuring, cluste

cated and neeents. Combustg combustionets. This diffe

ler “2” is desi

ets from wheat st

urface of the bters prevented

pellets.

straw pellets.

easured concermal performaof emission C1”. lets in boiler emissions of formance of c

mission CO wiler “2”. Whe

mited the comers of ash ex

d special burntion of straw n of straw perence was grigned to burn

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combustion ofwas 5245,3 men the measurmbustion of xtinguished th

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7 kW. mg.m-3 f straw mg.m-3 rement pellets he fire

ed grid ler “1” hermal ler “1” t types

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Acta Montanistica Slovaca Ročník 17 (2012), číslo 4, 283-289

289

The thermal performance of the boiler “2” had a downward trend. The concentration of CO has increased by 52.4 % when burning straw pellets in boiler “2” and NOx increased 3.6 times more in comparision with the combustion of wood pellets. In the case of boiler "1" it was worse. The formation of CO increased more than 5 times in the case of straw pellets and the concentration of NOx was 3.7 times more in comparision with the combustion of wood pellets. Larger amount of NOx in the both boilers is very similar, which is caused by a higher content of nitrogen in the phytomass as in dendromass. The concentration of CO is much higher in the second boiler “2”. This is because the burner of the boiler “2” is designed to burn agri-pellets and during combustion occurs the melting of ash and of clusters of ash. This resulted in imperfect combustion process, lower performance and higher production of CO emissions.

The above measurements have pointed to the fact that the combustion of agro - pellets is quite difficult and requires use of special burners. Measurements also showed that the purchase and burning of cheaper phytomass pellets in boilers designed to burn only wood pellets is inappropriate.

Acknowledgement: This work is supported by the financial assistance of the project VEGA No. 1/1353/12. I acknowledge the financing with thanks.

References

Hužvár, J., Kapjor:, A.: Project Micro-cogeneration Incl. The Conversion of Chemical Energy of Biomass to Electric Energy and low Potential Heat, Fourth Global Conference on Power Control and Optimalization, roč. 4, č. 1, 2010.

Hužvár, J., Nosek, R.: Impact of fuel supply to concentrations of emissions in domestic boiler. Power control and optimization, Malaysia, 2010, ISBN 978-983-44483-32.

Chabinski, M., Kubica, K., Szlęk, A.: Influence of control algorithm on efficiency and pollutant emission in small capacity stoker boiler, The 1st International Congress on Thermodynamics, 2011.

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Chudikova, P., Tausova, M., Erdelyiova, K., Taus, P.: Potential of dendromass in Slovak Republic and its actual exploitationin thermic economy. In: Acta Montanistica Slovaca, 15 (spec issue 2), pp. 139-145, 2011.

Jandačka, J., Holubčík, M., Papučík, Š, Jurkechová, J.: Spaľovacie a splyňovacie kotly na pevné palivá pre domácnosti. Žilina, Slovakia: Juraj Stefúň GEORG, 2011, ISBN 978-80-89401-38-3.

Jandačka, J., Papučík, Š., Nosek, R., Holubčík, M., Kapjor, A.: Environmentálne a energetické aspekty spaľovania biomasy, Žilina, Slovakia: Juraj Stefúň GEORG, 2011, ISBN 978-80-89401-40-6.

Nemec, P., Hužvár, J.: Proposal of heat exchanger in micro cogeneration unit, configuration with biomass combustion, Materials science and technology, 2011, ISSN 1335-9053.

Rybár, R., Tauš, P., Horbaj, P.: Technológie alternatívnych zdrojov vodná energia a biomasa, 1. vyd - Košice: ES F BERG TU - 2011. - 93 s.. - ISBN 978-80-553-0693-3.

Schmidl, C., Luisser, M., Padouvas, E., Lasselsberger, L., Rzaca, M., Ramirez-Santa Cruz, C., Handler, M., Peng, G., Bauer, H., Puxbaum, H.: Particulate and gaseous emissions from manually and automatically fired small scale combustion systems, Atmospheric Environment, Volume 45, Issue 39, December 2011, Pages 7443–7454, 2011, ISSN: 1352-2310.

Verma, V. K., Bram, S., Delattin, F., Laha, P., Vandendael, I., Hubin, A., De Ruyck, J.: Agro-pellets for domestic heating boilers: Standard laboratory and real life performance, Applied Energy, Volume 90, Issue 1, February 2012, Pages 17–23, ISSN: 0306-2619.