Dynamic Modeling of a BioGrate Boiler

Alexandre Boriouchkine

Dynamic Modeling of a BioGrate Boiler

Julkaisun otsikon käännös: BioGrate -kattilan dynaaminen mallinnus

Alexandre Boriouchkine

Kemian tekniikan ja metallurgian laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Biomassan polttoa pidetään tehokkaana energiantuotantomenetelmänä, joka mahdollistaa hupenevien fossiilisten polttoaineiden korvaamisen. Tämän lisäksi biomassa on sekä uusiutuva että CO2-neutraali luonnonvara, joka tarjoaa kestävän ratkaisun jatkuvasti kasvavalle energian kysynnälle. Olemassa olevat polttoteknologiat voivat hyödyntää biomassaa vain osittain, yleensä seoksena fossiilisten polttoaineiden kanssa. Tästä johtuen on kehitetty uusia teknologioita, kuten BioGrate-kattila, joka pystyy hyödyntämään uusiutuvia polttoaineita sellaisenaan. Tulevaisuuden energiajärjestelmät tulevat sisältämään yhä enemmän erilaisia energialähteitä joustavaan energian tuotantoon. Tämä kohdistaa kattilaprosesseihin uusia haasteita, kuten nopeita kuorman muutoksia sekä energiatuotantoa minimiteholla. Tämän takia onkin tärkeää ymmärtää järjestelmien kehityksessä palamisprosessissa tapahtuvat ilmiöt, sillä se mahdollistaa kattiloiden optimaalisen suunnittelun ja ajon. Tämä väitöskirja esittää Biograte-kattilalle mekanistisen mallin, joka mahdollistaa palamisilmiöiden tutkimisen. Tähän sisältyy erilaisten biomassan ominaisuuksien, kuten raekoon ja kosteuspitoisuuden vaikutuksen evaluointi sekä muuttuvan primääri-ilmansyötön vaikutuksen tutkiminen palavaan polttoainekerrokseen.. Mallin tarkkuuden parantamiseksi, BioGrate-kattilassa käytetylle polttoaineelle on määritetty pyrolyysikinetiikka ja siihen liittyvä reaktiolämpö on estimoitu tässä työssä myös kehitetyn pakattu-peti -pyrolyysimallin avulla. Kehitetty yksityiskohtainen mekanistinen malli on lisäksi yksinkertaistettu prosessin monitorointiin ja säätöön soveltuvaksi. Verrattuna yksityiskohtaiseen malliin, yksinkertaisempi malli pystyy kuvaamaan palamista riittävän tarkasti laskenta-ajan ollessa silti reaaliaikaa lyhyempi. Kummatkin mallit on validoitu kokeellisen data avulla ja kokeet osoittavat mallien ennustuskyvyn olevan riittävä kokeellisesti mitattujen palamisilmiöiden kuvaamisessa. Suoritettujen simulaatioiden avulla on tutkittu raekoon ja kosteuspitoisuuden vaikutusta biomassan palamiseen. Lisäksi on selvitetty palamisilman vaihtelun vaikutusta polttoaineen palamiseen. Yksityiskohtaisen mallin avulla on tutkittu raekoon ja kosteuspitoisuuden vaikutusta biomassan palamiseen BioGrate-kattilassa. Tämän lisäksi palamisilman vaihtelun vaikutusta polttoaineen palamiseen on selvitetty. Tulokset osoittivat, mallien avulla saadaan arvokasta tietoa BioGrate-kattilan tehokkuuden parantamiseen.

Julkaisun otsikon käännös	BioGrate -kattilan dynaaminen mallinnus
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Jämsä-Jounela, Sirkka-Liisa, Vastuuprofessori
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-6808-4
Sähköinen ISBN	978-952-60-6809-1
Tila	Julkaistu - 2016
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

biomassan poltto
mekanistinen mallinnus
palamisen mallinnus
pyrolyysin mallinnus
metsäkuusen kuoriaines
mekanistinen malli on-line laskentaan

YK:n kestävän kehityksen tavoitteet

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http://urn.fi/URN:ISBN:978-952-60-6809-1Lisenssi: Määrittelemätön

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@phdthesis{1a961282a52a48ac986576b33a50ca7d,

title = "Dynamic Modeling of a BioGrate Boiler",

abstract = "Biomass utilization in energy production through combustion is regarded as an efficient alternative to consuming diminishing fossil natural resources. Furthermore, biomass is not only a naturally replenishable energy source, but is also CO2 neutral, and thus it is a sustainable option to satisfy the ever-growing energy demand. Existing combustion technologies such as industrial boilers and furnaces can utilize renewable fuels to a certain degree only, mainly when blended with traditional fossil fuels. Consequently, new technologies have been developed, such as BioGrate boilers, which can fully benefit from biomass fuel.Furthermore, future energy systems will comprise an increasing variety of energy sources for flexible energy generation. This will impose new challenges on boiler systems in terms of rapid changes in power demand and the ability to operate under low-load conditions. Thus, the development of these systems will require an insight into the combustion process for the optimal design and operation of energy boilers. Mathematical modeling allows the acquisition of important knowledge on the combustion process and underlying phenomena. This thesis presents a mechanistic model for a BioGrate boiler developed for process phenomena investigation, including an evaluation of the effect of varying particle size and moisture content on biomass combustion and the dynamic response of the burning fuel bed to a varying primary air supply. To improve the accuracy of the developed model, appropriate pyrolysis kinetics for the debarking residue were determined and the associated reaction heats were estimated from a mechanistic model of fixed-bed pyrolysis, which was also developed in this work. In addition, a simplification of the developed model for process control and monitoring is presented. The simplified model demonstrated acceptable accuracy in comparison with the detailed model and faster-than-real-time computational times. Both models were successfully validated with experimental data and showed the ability to predict the observed experimental trends. The results indicate that the model provides valuable information for improving the efficiency of a BioGrate boiler.",

keywords = "biomass combustion, mechanistic modeling, combustion modeling, pyrolysis modeling, Norway spruce debarking residue, mechanistic model for on-line computations, biomassan poltto, mekanistinen mallinnus, palamisen mallinnus, pyrolyysin mallinnus, mets{\"a}kuusen kuoriaines, mekanistinen malli on-line laskentaan, biomass combustion, mechanistic modeling, combustion modeling, pyrolysis modeling, Norway spruce debarking residue, mechanistic model for on-line computations",

author = "Alexandre Boriouchkine",

year = "2016",

language = "English",

isbn = "978-952-60-6808-4",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "92",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Dynamic Modeling of a BioGrate Boiler

AU - Boriouchkine, Alexandre

PY - 2016

Y1 - 2016

N2 - Biomass utilization in energy production through combustion is regarded as an efficient alternative to consuming diminishing fossil natural resources. Furthermore, biomass is not only a naturally replenishable energy source, but is also CO2 neutral, and thus it is a sustainable option to satisfy the ever-growing energy demand. Existing combustion technologies such as industrial boilers and furnaces can utilize renewable fuels to a certain degree only, mainly when blended with traditional fossil fuels. Consequently, new technologies have been developed, such as BioGrate boilers, which can fully benefit from biomass fuel.Furthermore, future energy systems will comprise an increasing variety of energy sources for flexible energy generation. This will impose new challenges on boiler systems in terms of rapid changes in power demand and the ability to operate under low-load conditions. Thus, the development of these systems will require an insight into the combustion process for the optimal design and operation of energy boilers. Mathematical modeling allows the acquisition of important knowledge on the combustion process and underlying phenomena. This thesis presents a mechanistic model for a BioGrate boiler developed for process phenomena investigation, including an evaluation of the effect of varying particle size and moisture content on biomass combustion and the dynamic response of the burning fuel bed to a varying primary air supply. To improve the accuracy of the developed model, appropriate pyrolysis kinetics for the debarking residue were determined and the associated reaction heats were estimated from a mechanistic model of fixed-bed pyrolysis, which was also developed in this work. In addition, a simplification of the developed model for process control and monitoring is presented. The simplified model demonstrated acceptable accuracy in comparison with the detailed model and faster-than-real-time computational times. Both models were successfully validated with experimental data and showed the ability to predict the observed experimental trends. The results indicate that the model provides valuable information for improving the efficiency of a BioGrate boiler.

AB - Biomass utilization in energy production through combustion is regarded as an efficient alternative to consuming diminishing fossil natural resources. Furthermore, biomass is not only a naturally replenishable energy source, but is also CO2 neutral, and thus it is a sustainable option to satisfy the ever-growing energy demand. Existing combustion technologies such as industrial boilers and furnaces can utilize renewable fuels to a certain degree only, mainly when blended with traditional fossil fuels. Consequently, new technologies have been developed, such as BioGrate boilers, which can fully benefit from biomass fuel.Furthermore, future energy systems will comprise an increasing variety of energy sources for flexible energy generation. This will impose new challenges on boiler systems in terms of rapid changes in power demand and the ability to operate under low-load conditions. Thus, the development of these systems will require an insight into the combustion process for the optimal design and operation of energy boilers. Mathematical modeling allows the acquisition of important knowledge on the combustion process and underlying phenomena. This thesis presents a mechanistic model for a BioGrate boiler developed for process phenomena investigation, including an evaluation of the effect of varying particle size and moisture content on biomass combustion and the dynamic response of the burning fuel bed to a varying primary air supply. To improve the accuracy of the developed model, appropriate pyrolysis kinetics for the debarking residue were determined and the associated reaction heats were estimated from a mechanistic model of fixed-bed pyrolysis, which was also developed in this work. In addition, a simplification of the developed model for process control and monitoring is presented. The simplified model demonstrated acceptable accuracy in comparison with the detailed model and faster-than-real-time computational times. Both models were successfully validated with experimental data and showed the ability to predict the observed experimental trends. The results indicate that the model provides valuable information for improving the efficiency of a BioGrate boiler.

KW - biomass combustion

KW - mechanistic modeling

KW - combustion modeling

KW - pyrolysis modeling

KW - Norway spruce debarking residue

KW - mechanistic model for on-line computations

KW - biomassan poltto

KW - mekanistinen mallinnus

KW - palamisen mallinnus

KW - pyrolyysin mallinnus

KW - metsäkuusen kuoriaines

KW - mekanistinen malli on-line laskentaan

KW - biomass combustion

KW - mechanistic modeling

KW - combustion modeling

KW - pyrolysis modeling

KW - Norway spruce debarking residue

KW - mechanistic model for on-line computations

M3 - Doctoral Thesis

SN - 978-952-60-6808-4

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Dynamic Modeling of a BioGrate Boiler

Abstrakti

Tutkimusalat

YK:n kestävän kehityksen tavoitteet

Pääsy asiakirjaan

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