Of the many thermochemical conversion pathways for utilizing biomass as a renewable energy source, fast pyrolysis is a promising method for converting and upgrading carbonaceous feedstocks into a range of liquid fuels for use in heat, electricity and transportation applications. Experimental trials have been carried out to assess the impact of operational parameters on process yields. However, dealing with larger-scale experimental systems comes at the expense of lengthy and resource-intensive experiments. Luckily, the advances in computing technology and numerical algorithm solvers have allowed reactor modelling to be an attractive opportunity for reactor design, optimization and experimental data interpretation in a cost-effective fashion. In this work, a fluidized bed reactor model for biomass fast pyrolysis was developed and applied to the Bell’s Corners Complex (BCC) fluidized bed fast pyrolysis unit located at NRCan CanmetENERGY (Ottawa, Canada) for testing and validation. The model was programmed using the Microsoft Visual Basic for Applications software with the motivation of facilitating use and accessibility as well as minimizing runtime and input requirements. The application of different biomass devolatilization schemes within the model was conducted, not only for biomass fast pyrolysis product quantity but also liquid product composition (quality), to examine the effect of variable reaction kinetic sub-models on product yields. The model predictions were in good agreement with the results generated from the experimental work and mechanism modifications were proposed which further increased the accuracy of model predictions. Successively, the formulation of the modelled fluid dynamic scheme was adapted to study the effect of variable hydrodynamic sub-models on product yields for which no significant effect was observed. The work also looked into effect of the dominant process variables such as feedstock composition, bed temperature, fluidizing velocity and feedstock size on measurable product outputs (bio-oil, gas and biochar) and compared the results to those generated from the experimental fast pyrolysis unit. The ideal parameters for maximizing bio-oil yield have been determined to be those which: minimize the content of lignin and inorganic minerals in the feedstock, maintain the dense-bed temperature in a temperature range of 450-520 ºC, maximize the fluidization velocity without leading to bed entrainment, and limit the feedstock particle size to a maximum of 2000 μm.

Biochar has been heralded as a promising technology for climate change mitigation that can also benefit soils. Biochar is a carbonaceous solid produced by pyrolysis of biomass – the thermal decomposition of plant and plant-derived matter in the absence of oxygen. When added to soils, biochar has the potential to increase crop yields and suppress soil emissions of greenhouse gases, whilst sequestering carbon in a stable form. In addition to biochar, biomass pyrolysis produces liquids and gases that can serve as biofuels. Biochar production systems that generate excess heat or power are particularly environmentally and economically attractive. Rotary kilns are the favoured process reactor in many industries, given their potential to handle a wide range of feedstocks and provide good process control. This thesis investigates the potential to coproduce biochar and excess biofuels by slow pyrolysis in a pilot-scale rotary kiln. The work attempts to progress towards the ultimate aim of scaling up the rotary kiln and optimising its operating conditions to produce biochar of good quality along with an excess of useful biofuels. Experimental work, involving the development and application of new methodologies, was used to gain a better understanding of the process. The data gathered were then used to support preliminary numerical simulation efforts towards the development of a comprehensive process model. Five biomass feedstocks were considered: softwood pellets, miscanthus straw pellets, wheat straw pellets, oilseed rape straw pellets and raw rice husks. The granular flow of biomass feedstocks was observed in a short closed drum faced with acrylic and resting on rollers. All pelletized feedstocks displayed similar angles of repose, validating the use of softwood pellets as a model biomass for these feedstocks. Bed mixing, which can improve product uniformity, was slow under typical operating conditions, requiring 5 min to complete at 4 rpm for softwood pellets. Mixing quickened considerably at higher rotation rates. A digital image analysis method was developed to measure the distribution of solid residence times inside the rotary kiln. The mean residence time of softwood pellets ranged from 19 to 37 min under typical operating conditions, decreasing with increases in kiln rotation rate, but mostly unaffected by feeding rates. These findings show that kiln rotation rates must be selected to balance the residence time of solids inside the kiln with bed mixing levels. Thermogravimetry and differential scanning calorimetry were performed on samples of ground softwood pellets under five different heating profiles to study the kinetics and heat flows of the pyrolysis process. Both exothermic and endothermic regions were identified, with most reactions taking place between 250°C and 500°C. Results suggest that exothermic pyrolysis reactions can be promoted by altering the process heating rate, thereby improving net biofuel yield from the process. The thermogravimetric data collected was used to develop a distributed activation energy model (DAEM) of the kinetics of softwood pellet pyrolysis for integration into a comprehensive model of the process. The applicability of the kinetic model to large-scale processes was confirmed using a simplified process model developed to simulate biomass pyrolysis inside the pilot-scale rotary kiln. Although crude, the simplified process model produced sufficiently accurate estimates of char yield for preliminary design purposes. The simplified model also allowed important process parameters, such as kiln filling degree, solid residence time and heating rate, to be evaluated. A series of pyrolysis experiments was performed on the pilot-scale rotary kiln to evaluate the yields of biochar and biofuels and determine the temperature profile inside the kiln. This work required the design of a suspended thermocouple system that measures temperatures along the kiln, both in the gas phase and inside the solid bed. For most experiments at 550°C, a region of high temperature gas and solids was observed, possibly indicative of exothermic reactions. Biochar yield varied from 18% to 73% over the range of feedstocks and operating conditions tested. A vapour sampling methodology that relies on the use of a tracer gas was developed to determine the yield of pyrolysis liquids and gases. Due to analytical difficulties, it was not possible to obtain accurate mass closure with this method. However, the methodology revealed significant air ingress into the pilot-scale rotary kiln that is responsible for partially combusting biofuels produced by the process, thereby reducing their calorific value. Energy balances on the kiln confirmed that the calorific content of pyrolysis liquids and gases exceeds the energetic demand of the process, yielding between 0.3 and 11 MJ in excess biofuels per kg of biomass feedstock. An attempt was made to develop a multiphase model of the flow of vapours and solids inside the rotary kiln using computational fluid dynamics (CFD), but the continuous modelling approach was found inadequate to simulate the dense bed of biomass inside the kiln. The discrete element method (DEM) was sought as an alternative to model the granular flow of biomass inside the kiln. Extensive parameter calibration was required to reproduce the experimental behaviour of softwood pellets observed in the short closed drum. A model of the pilot-scale rotary kiln was constructed to simulate particle residence times. Further parameter calibration was required to replicate softwood pellet holdup inside the kiln. The calibrated model was able to reproduce the mean residence time of softwood pellets within 10% under different kiln operating conditions. However, simulated residence time distributions could not be established as a result of the long execution times required for this modelling work. Few data are currently available on large-scale continuous biomass pyrolysis processes; the experimental data gathered in this thesis help to fill this gap. Along with the numerical simulation work presented herein, they provide the foundation for the development of a comprehensive model of biomass pyrolysis in rotary kilns. Such a numerical model would prove invaluable in scaling up the process and maximizing its efficiency. Future work should consider the agronomic value and carbon sequestration potential of biochar produced under different operating conditions. In addition, the performance and efficiency of different conversion technologies for generating heat and power from biofuels need to be investigated.

Diferentes resíduos são gerados pelas indústrias siderúrgicas, dentre eles o resíduo dos trituradores de sucata (RTS). O destino mais utilizado para o RTS pelas indústrias siderúrgicas brasileiras é o aterro de resíduos industriais. A pirólise se apresenta como uma alternativa para o reaproveitamento do RTS. O objetivo deste trabalho foi avaliar o efeito de diferentes parâmetros operacionais sobre as propriedades e o rendimento dos produtos do processo de pirólise do RTS para fins de um posterior aproveitamento. Um reator de pirólise de leito fixo foi utilizado e as seguintes variáveis foram testadas fazendo-se uso de um planejamento experimental 2k: temperatura (500, 600 e 700 ºC), taxa de aquecimento (5, 20, 35 ºC/min), vazão de gás inerte (N2) (0,03, 0,44 e 0,76 L/min) e razão CaO/RTS (0, 1 e 2). A utilização de uma taxa de aquecimento menor, associada a presença de CaO, resultou nos maiores rendimentos de gás não-condensável (> 50%). O poder calorífico deste gás, aumentou com o incremento da razão CaO/RTS. Este aumento foi atribuído a captura in situ do CO2. A utilização de uma vazão maior de gás inerte, também favoreceu o aumento do poder calorífico do gás não-condensável. Os maiores valores obtidos (25 MJ/Nm3) são apreciáveis, considerando o poder calorífico de outros combustíveis. Os maiores rendimentos de char (> 24%) foram obtidos nos experimentos com a utilização de uma temperatura menor, associada a ausência de CaO. A utilização de uma taxa de aquecimento mais elevada resultou em maiores rendimentos de voláteis condensáveis. Os menores rendimentos de voláteis condensáveis foram obtidos quando a vazão de inerte foi menor. Também foi possível verificar que, houve um aumento do rendimento de voláteis condensáveis com a presença de CaO para a temperatura de 700 ºC. Este comportamento foi atribuído ao maior rendimento global de estireno nas referidas condições operacionais. O rendimento global de 2,4-dimetil-1-heptano também apresentou comportamento semelhante ao observado para o rendimento de voláteis condensáveis, indicando que o AlCl3 pode ter atuado como catalisador da pirólise do PP presente no RTS. Com o aumento da razão CaO/RTS, houve uma redução da concentração de CO2. A redução da concentração de CO2 na presença de CaO está associada a formação de CaCO3. A retenção de cloro no char foi mais elevada nos ensaios conduzidos na presença de CaO. Verificou-se uma redução da retenção de cloro no char com o aumento da temperatura para os ensaios conduzidos na presença de CaO. Uma diminuição da retenção de metais no char foi verificada nos experimentos conduzidos com CaO para os seguintes metais: Co, Cu, Cr, Fe, Ni e Zn. A remoção do cloro permitiria conduzir o processo de pirólise a temperaturas mais elevadas, aumentando a Eficiência Energética mínima (EE) do processo. Desta forma, fica clara a necessidade da remoção do cloro do RTS antes do processo de pirólise, pois a partir disto o uso do CaO contribuiria para o aumento da EE e da retenção de metais no char, e consequentemente da desejabilidade global. / Different wastes are generated by steel industries, among them the shredder residue (SR). The most commonly used destination for SR by Brazilian steel industry is the landfill of industrial waste. The pyrolysis can be considered a solution to this problem. The aim of this work was to evaluate the effects of different operating parameters upon the properties and yield of the SR pyrolysis process products for later use. A fixed bed pyrolysis reactor was used and the following variables were tested using a 2k experimental design: temperature (500, 600 and 700 ºC), heating rate (5, 20, 35 ºC/min), flow rate of inert gas (N2) (0.03, 0.44 and 0.76 L/min) and CaO/SR ratio (0, 1 and 2). The use of a lower heating rate, associated with the CaO presence, resulted in higher yields of non-condensable gas (> 50%). The calorific value of this gas increased with the growth of the CaO/SR ratio. This increase was attributed to an in situ CO2 capture. The use of a higher flow rate of inert gas also favored the increase in the calorific power of the non-condensable gas. The highest values (25 MJ/Nm3) are appreciable considering the calorific value of other fuels. The highest char yields (> 24%) were obtained in the experiments using a lower temperature associated with the absence of CaO. The use of a higher heating rate resulted in higher yields of condensable volatiles. The lower yields of condensable volatiles were obtained when the inert flow rate was lower. It was also possible to verify that there was an increase in the condensable volatiles yield with the CaO presence at a temperature of 700 ºC.This behavior was attributed to the higher styrene overall yield under these operating conditions. The 2,4-dimethyl-1-heptane overall yield also presented a similar behavior to that observed for the condensable volatiles yield, indicating that the AlCl3 may have acted as a catalyst for the PP pyrolysis present in the SR. With the increase in the CaO/RTS ratio, there was a reduction in the CO2 concentration. The CO2 concentration reduction in the CaO presence is associated with the CaCO3 formation. The chlorine retention in the char was higher in the experiments conducted with CaO presence. A reduction in the chlorine retention in char was observed with increasing temperature for the experiments conducted with CaO presence. A decrease in metal retention in the char was verified in the experiments conducted with CaO for the following metals: Co, Cu, Cr, Fe, Ni and Zn. Chlorine removal would allow the pyrolysis process to be conducted at higher temperatures, increasing the minimum energy efficiency (EE) of the process. Therefore, it is clear the need to remove chlorine from the SR before the pyrolysis process, since, the CaO use would contribute to the EE increase and the retention of metals in the char, and consequently the global desirability.

Diferentes resíduos são gerados pelas indústrias siderúrgicas, dentre eles o resíduo dos trituradores de sucata (RTS). O destino mais utilizado para o RTS pelas indústrias siderúrgicas brasileiras é o aterro de resíduos industriais. A pirólise se apresenta como uma alternativa para o reaproveitamento do RTS. O objetivo deste trabalho foi avaliar o efeito de diferentes parâmetros operacionais sobre as propriedades e o rendimento dos produtos do processo de pirólise do RTS para fins de um posterior aproveitamento. Um reator de pirólise de leito fixo foi utilizado e as seguintes variáveis foram testadas fazendo-se uso de um planejamento experimental 2k: temperatura (500, 600 e 700 ºC), taxa de aquecimento (5, 20, 35 ºC/min), vazão de gás inerte (N2) (0,03, 0,44 e 0,76 L/min) e razão CaO/RTS (0, 1 e 2). A utilização de uma taxa de aquecimento menor, associada a presença de CaO, resultou nos maiores rendimentos de gás não-condensável (> 50%). O poder calorífico deste gás, aumentou com o incremento da razão CaO/RTS. Este aumento foi atribuído a captura in situ do CO2. A utilização de uma vazão maior de gás inerte, também favoreceu o aumento do poder calorífico do gás não-condensável. Os maiores valores obtidos (25 MJ/Nm3) são apreciáveis, considerando o poder calorífico de outros combustíveis. Os maiores rendimentos de char (> 24%) foram obtidos nos experimentos com a utilização de uma temperatura menor, associada a ausência de CaO. A utilização de uma taxa de aquecimento mais elevada resultou em maiores rendimentos de voláteis condensáveis. Os menores rendimentos de voláteis condensáveis foram obtidos quando a vazão de inerte foi menor. Também foi possível verificar que, houve um aumento do rendimento de voláteis condensáveis com a presença de CaO para a temperatura de 700 ºC. Este comportamento foi atribuído ao maior rendimento global de estireno nas referidas condições operacionais. O rendimento global de 2,4-dimetil-1-heptano também apresentou comportamento semelhante ao observado para o rendimento de voláteis condensáveis, indicando que o AlCl3 pode ter atuado como catalisador da pirólise do PP presente no RTS. Com o aumento da razão CaO/RTS, houve uma redução da concentração de CO2. A redução da concentração de CO2 na presença de CaO está associada a formação de CaCO3. A retenção de cloro no char foi mais elevada nos ensaios conduzidos na presença de CaO. Verificou-se uma redução da retenção de cloro no char com o aumento da temperatura para os ensaios conduzidos na presença de CaO. Uma diminuição da retenção de metais no char foi verificada nos experimentos conduzidos com CaO para os seguintes metais: Co, Cu, Cr, Fe, Ni e Zn. A remoção do cloro permitiria conduzir o processo de pirólise a temperaturas mais elevadas, aumentando a Eficiência Energética mínima (EE) do processo. Desta forma, fica clara a necessidade da remoção do cloro do RTS antes do processo de pirólise, pois a partir disto o uso do CaO contribuiria para o aumento da EE e da retenção de metais no char, e consequentemente da desejabilidade global. / Different wastes are generated by steel industries, among them the shredder residue (SR). The most commonly used destination for SR by Brazilian steel industry is the landfill of industrial waste. The pyrolysis can be considered a solution to this problem. The aim of this work was to evaluate the effects of different operating parameters upon the properties and yield of the SR pyrolysis process products for later use. A fixed bed pyrolysis reactor was used and the following variables were tested using a 2k experimental design: temperature (500, 600 and 700 ºC), heating rate (5, 20, 35 ºC/min), flow rate of inert gas (N2) (0.03, 0.44 and 0.76 L/min) and CaO/SR ratio (0, 1 and 2). The use of a lower heating rate, associated with the CaO presence, resulted in higher yields of non-condensable gas (> 50%). The calorific value of this gas increased with the growth of the CaO/SR ratio. This increase was attributed to an in situ CO2 capture. The use of a higher flow rate of inert gas also favored the increase in the calorific power of the non-condensable gas. The highest values (25 MJ/Nm3) are appreciable considering the calorific value of other fuels. The highest char yields (> 24%) were obtained in the experiments using a lower temperature associated with the absence of CaO. The use of a higher heating rate resulted in higher yields of condensable volatiles. The lower yields of condensable volatiles were obtained when the inert flow rate was lower. It was also possible to verify that there was an increase in the condensable volatiles yield with the CaO presence at a temperature of 700 ºC.This behavior was attributed to the higher styrene overall yield under these operating conditions. The 2,4-dimethyl-1-heptane overall yield also presented a similar behavior to that observed for the condensable volatiles yield, indicating that the AlCl3 may have acted as a catalyst for the PP pyrolysis present in the SR. With the increase in the CaO/RTS ratio, there was a reduction in the CO2 concentration. The CO2 concentration reduction in the CaO presence is associated with the CaCO3 formation. The chlorine retention in the char was higher in the experiments conducted with CaO presence. A reduction in the chlorine retention in char was observed with increasing temperature for the experiments conducted with CaO presence. A decrease in metal retention in the char was verified in the experiments conducted with CaO for the following metals: Co, Cu, Cr, Fe, Ni and Zn. Chlorine removal would allow the pyrolysis process to be conducted at higher temperatures, increasing the minimum energy efficiency (EE) of the process. Therefore, it is clear the need to remove chlorine from the SR before the pyrolysis process, since, the CaO use would contribute to the EE increase and the retention of metals in the char, and consequently the global desirability.

Diferentes resíduos são gerados pelas indústrias siderúrgicas, dentre eles o resíduo dos trituradores de sucata (RTS). O destino mais utilizado para o RTS pelas indústrias siderúrgicas brasileiras é o aterro de resíduos industriais. A pirólise se apresenta como uma alternativa para o reaproveitamento do RTS. O objetivo deste trabalho foi avaliar o efeito de diferentes parâmetros operacionais sobre as propriedades e o rendimento dos produtos do processo de pirólise do RTS para fins de um posterior aproveitamento. Um reator de pirólise de leito fixo foi utilizado e as seguintes variáveis foram testadas fazendo-se uso de um planejamento experimental 2k: temperatura (500, 600 e 700 ºC), taxa de aquecimento (5, 20, 35 ºC/min), vazão de gás inerte (N2) (0,03, 0,44 e 0,76 L/min) e razão CaO/RTS (0, 1 e 2). A utilização de uma taxa de aquecimento menor, associada a presença de CaO, resultou nos maiores rendimentos de gás não-condensável (> 50%). O poder calorífico deste gás, aumentou com o incremento da razão CaO/RTS. Este aumento foi atribuído a captura in situ do CO2. A utilização de uma vazão maior de gás inerte, também favoreceu o aumento do poder calorífico do gás não-condensável. Os maiores valores obtidos (25 MJ/Nm3) são apreciáveis, considerando o poder calorífico de outros combustíveis. Os maiores rendimentos de char (> 24%) foram obtidos nos experimentos com a utilização de uma temperatura menor, associada a ausência de CaO. A utilização de uma taxa de aquecimento mais elevada resultou em maiores rendimentos de voláteis condensáveis. Os menores rendimentos de voláteis condensáveis foram obtidos quando a vazão de inerte foi menor. Também foi possível verificar que, houve um aumento do rendimento de voláteis condensáveis com a presença de CaO para a temperatura de 700 ºC. Este comportamento foi atribuído ao maior rendimento global de estireno nas referidas condições operacionais. O rendimento global de 2,4-dimetil-1-heptano também apresentou comportamento semelhante ao observado para o rendimento de voláteis condensáveis, indicando que o AlCl3 pode ter atuado como catalisador da pirólise do PP presente no RTS. Com o aumento da razão CaO/RTS, houve uma redução da concentração de CO2. A redução da concentração de CO2 na presença de CaO está associada a formação de CaCO3. A retenção de cloro no char foi mais elevada nos ensaios conduzidos na presença de CaO. Verificou-se uma redução da retenção de cloro no char com o aumento da temperatura para os ensaios conduzidos na presença de CaO. Uma diminuição da retenção de metais no char foi verificada nos experimentos conduzidos com CaO para os seguintes metais: Co, Cu, Cr, Fe, Ni e Zn. A remoção do cloro permitiria conduzir o processo de pirólise a temperaturas mais elevadas, aumentando a Eficiência Energética mínima (EE) do processo. Desta forma, fica clara a necessidade da remoção do cloro do RTS antes do processo de pirólise, pois a partir disto o uso do CaO contribuiria para o aumento da EE e da retenção de metais no char, e consequentemente da desejabilidade global. / Different wastes are generated by steel industries, among them the shredder residue (SR). The most commonly used destination for SR by Brazilian steel industry is the landfill of industrial waste. The pyrolysis can be considered a solution to this problem. The aim of this work was to evaluate the effects of different operating parameters upon the properties and yield of the SR pyrolysis process products for later use. A fixed bed pyrolysis reactor was used and the following variables were tested using a 2k experimental design: temperature (500, 600 and 700 ºC), heating rate (5, 20, 35 ºC/min), flow rate of inert gas (N2) (0.03, 0.44 and 0.76 L/min) and CaO/SR ratio (0, 1 and 2). The use of a lower heating rate, associated with the CaO presence, resulted in higher yields of non-condensable gas (> 50%). The calorific value of this gas increased with the growth of the CaO/SR ratio. This increase was attributed to an in situ CO2 capture. The use of a higher flow rate of inert gas also favored the increase in the calorific power of the non-condensable gas. The highest values (25 MJ/Nm3) are appreciable considering the calorific value of other fuels. The highest char yields (> 24%) were obtained in the experiments using a lower temperature associated with the absence of CaO. The use of a higher heating rate resulted in higher yields of condensable volatiles. The lower yields of condensable volatiles were obtained when the inert flow rate was lower. It was also possible to verify that there was an increase in the condensable volatiles yield with the CaO presence at a temperature of 700 ºC.This behavior was attributed to the higher styrene overall yield under these operating conditions. The 2,4-dimethyl-1-heptane overall yield also presented a similar behavior to that observed for the condensable volatiles yield, indicating that the AlCl3 may have acted as a catalyst for the PP pyrolysis present in the SR. With the increase in the CaO/RTS ratio, there was a reduction in the CO2 concentration. The CO2 concentration reduction in the CaO presence is associated with the CaCO3 formation. The chlorine retention in the char was higher in the experiments conducted with CaO presence. A reduction in the chlorine retention in char was observed with increasing temperature for the experiments conducted with CaO presence. A decrease in metal retention in the char was verified in the experiments conducted with CaO for the following metals: Co, Cu, Cr, Fe, Ni and Zn. Chlorine removal would allow the pyrolysis process to be conducted at higher temperatures, increasing the minimum energy efficiency (EE) of the process. Therefore, it is clear the need to remove chlorine from the SR before the pyrolysis process, since, the CaO use would contribute to the EE increase and the retention of metals in the char, and consequently the global desirability.

Les dysfonctionnements observés dans les enceintes de conversion thermochimique tels que les zones mortes et les courts-Circuits conduisent en général à une mauvaise valorisation de la ressource énergétique et à une pollution atmosphérique. Ils trouvent leur origine dans les conditions aérauliques au sein de ces enceintes. Ils pourront alors être évités par une meilleure maîtrise de ces écoulements. Nous proposons dans ce travail d’une part, le développement d’un nouvel outil pour la détermination de la distribution des temps de séjour de la phase solide, basé sur la luminescence de particules préalablement enrobées de pigments phosphorescents. Cette méthode systémique, optique, non intrusive et souple d’emploi a été mise en place à l’échelle laboratoire sur un banc d’essais aéraulique. D’autre part, nous avons développé un modèle numérique permettant de déterminer la distribution des temps de séjour afin de maîtriser les écoulements à la sortie des enceintes en vue de les optimiser et les extrapoler à l’échelle industrielle. Cette approche analytique est basée sur une modélisation par couplage MFN de type volumes finis du comportement d’un fluide à l’aide du Code Saturne et DEM de type éléments discrets du comportement du solide à l’aide du code SIGRAME. Enfin une confrontation de la DTS du modèle numérique avec laDTS expérimentale a été réalisée. / Dysfunctions observed in thermochemical conversion reactors like dead zones and short circuits generally lead to inaccurate pricing of energy resources and air pollution. They originate in the air flow conditions in these aeraulic reactor. They can then be avoided by a better control of these flows. We propose in this work to develop a new tool for determining the distribution of residence time of the solid phase, based on the luminescence of particles previously coated with phosphorescent pigments. This optical method, non-Intrusive and flexible, has been implemented at a laboratory scale, on an aeraulic test bench.On the other hand, we have developed a numerical model allowing to determine the distribution of the residence time to master the flows at the exit of surrounding walls to optimize them and extrapolate them at the industrial scale. This analytical approach is based on a modelling by coupling MFN by finite volume types via the Code Saturn and DEM by discrete elements of the solid behavior by means of the code SIGRAME. Finally a confrontation of the DTS of the digital model with the experimental DTS has been done.

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The main objective of this thesis was to determine how far a biomass quantity, equal to the potential produced within the Swedish borders, could cover the present energy needs inSwedenwith respect to economic and ecological circumstances. Three scenarios were studied where the available biomass was converted to heat, electricity and vehicle fuel. Three different amounts of biomass supply were studied for each scenario: 1) potential biomass amounts derived from forestry, non-forest land, forest industry and community; 2) the same amounts as in Case 1, plus the potential biomass amounts derived from agriculture; 3) the same amounts as in Case 1, plus 50% of the potential pulpwood quantity. For evaluating the economic and ecological circumstances of using biomass in the Swedish energy system, the scenarios were complemented with energy, cost and emergy analysis. The scenarios indicated that it may be possible to produce 170.2 PJ (47.3 TWh) per year of electricity from the biomass amounts in Case 2. From the same amount of biomass, the maximum annual production of hydrogen was 241.5 PJ (67.1 TWh) per year or 197.2 PJ (54.8 TWh) per year of methanol. The energy analysis showed that the ratio of energy output to energy input for large-scale applications ranged from 1.9 at electric power generation by gasification of straw to 40 at district heating generation by combustion of recovered wood. The cost of electricity at gasification ranged from 7.95 to 22.58 €/GJ. The cost of vehicle work generated by using hydrogen produced from forestry biomass in novel fuel cells was economically competitive compared to today’s propulsion systems. However, the cost of vehicle work generated by using methanol produced from forestry biomass in combustion engines was rather higher compared to use of petrol in petrol engines. The emergy analysis indicated that the only biomass assortment studied with a larger emergy flow from the local environment, in relation to the emergy flow invested from society after conversion, was fuel wood from non-forest land. However, even use of this biomass assortment for production of heat, electricity or vehicle fuels had smaller yields of emergy output in relation to emergy invested from society compared to alternative conversion processes; thus, the net contribution of emergy generated to the economy was smaller compared to these alternative conversion processes. / <p>QC 20120217</p>

The firing of fuel wood has been identified as one of themain causes of pollutant emissions from small-scale (&lt;100kW) combustion of wood fuels. The emissions are a result ofinsufficient combustion efficiency. This thesis presents a newmeasurement method to analyse the thermochemical conversion ofbiofuels in general, as well as to explain the main reason ofthe inefficient combustion of fuel wood in particular. In general, small-scale combustion of biofuels are carriedout by means of packed-bed combustion (PBC)technology. Acomprehensive literature review revealed that textbooks,theories, and methods in the field of thermochemical conversionof solid fuels in the context of PBC are scarce. This authorneeded a theoretical platform for systematic research on PBC ofbiofuels. Consequently, a new system theory - the three-stepmodel - was developed, describing the objectives of, theefficiencies of, and the process flows between, the leastcommon functions (subsystems) of a PBC system. The three stepsare referred to as the conversion system, the combustionsystem, and the heat exchanger system (boiler system). A numberof quantities and concepts, such as solid-fuel convertibles,conversion gas, conversion efficiency, and combustionefficiency, are deduced in the context of the three-step model.Based on the three-step model a measurement method washypothetically modelled aiming at the central physicalquantities of the conversion system, that is, the mass flow andstoichiometry of conversion gas, as well as the air factor ofthe conversion system. An uncertainty propagation analysis ofthe constitutive mathematical models of the method was carriedout. It indicated that it should be possible to determine themass flow and stoichiometry of conversion gas within the rangesof relative uncertainties of ±5% and ±7%,respectively. An experimental PBC system was constructed,according to the criteria defined by the hypothetical method.Finally, the method was verified with respect to total massflow of conversion gas in good agreement with the verificationmethod. The relative error of mass flow of conversion gas wasin the range of ±5% of the actual value predicted by theverification method. One experimental series was conducted applying the newmeasurement method. The studied conversion concept correspondedto overfired, updraft, horizontal fixed grate, and verticalcylindrical batch reactor. The measurements revealed newinformation on the similarities and the differences in theconversion behaviour of wood chips, wood pellets, and fuelwood. The course of a batch conversion has proven to be highlydynamic and stochastic. The dynamic range of the air factor ofthe conversion system during a run was 10:1. The empiricalstoichiometry of conversion gas during a run was CH3.1O:CH0O0. Finally ,this experimental series revealed one ofthe main reasons why fuel wood is more difficult to burn thanfor example wood pellets. The relatively dry fuel wood (12-31g/m2,s) displayed a significantly lower time-integratedmean of mass flux of conversion gas than both the wood pellets(37-62 g/m2,s) and the wood chips (50-90 g/m2,s). The higher the mass flux of conversion gasproduced in the conversion system, the higher the combustiontemperature for a given combustion system, which in turn ispositively coupled to the combustion efficiency. In future work the method will be improved so thatmeasurements of combustion efficiency can be carried out. Othertypes of conversion concepts will be studied by the method. Keywords: Packed-bed combustion, thermochemical conversionof biomass, solid-fuel combustion, fuel-bed combustion, gratecombustion, biomass combustion, gasification, pyrolysis,drying.

<p>The firing of fuel wood has been identified as one of themain causes of pollutant emissions from small-scale (<100kW) combustion of wood fuels. The emissions are a result ofinsufficient combustion efficiency. This thesis presents a newmeasurement method to analyse the thermochemical conversion ofbiofuels in general, as well as to explain the main reason ofthe inefficient combustion of fuel wood in particular.</p><p>In general, small-scale combustion of biofuels are carriedout by means of packed-bed combustion (PBC)technology. Acomprehensive literature review revealed that textbooks,theories, and methods in the field of thermochemical conversionof solid fuels in the context of PBC are scarce. This authorneeded a theoretical platform for systematic research on PBC ofbiofuels. Consequently, a new system theory - the three-stepmodel - was developed, describing the objectives of, theefficiencies of, and the process flows between, the leastcommon functions (subsystems) of a PBC system. The three stepsare referred to as the conversion system, the combustionsystem, and the heat exchanger system (boiler system). A numberof quantities and concepts, such as solid-fuel convertibles,conversion gas, conversion efficiency, and combustionefficiency, are deduced in the context of the three-step model.Based on the three-step model a measurement method washypothetically modelled aiming at the central physicalquantities of the conversion system, that is, the mass flow andstoichiometry of conversion gas, as well as the air factor ofthe conversion system. An uncertainty propagation analysis ofthe constitutive mathematical models of the method was carriedout. It indicated that it should be possible to determine themass flow and stoichiometry of conversion gas within the rangesof relative uncertainties of ±5% and ±7%,respectively. An experimental PBC system was constructed,according to the criteria defined by the hypothetical method.Finally, the method was verified with respect to total massflow of conversion gas in good agreement with the verificationmethod. The relative error of mass flow of conversion gas wasin the range of ±5% of the actual value predicted by theverification method.</p><p>One experimental series was conducted applying the newmeasurement method. The studied conversion concept correspondedto overfired, updraft, horizontal fixed grate, and verticalcylindrical batch reactor. The measurements revealed newinformation on the similarities and the differences in theconversion behaviour of wood chips, wood pellets, and fuelwood. The course of a batch conversion has proven to be highlydynamic and stochastic. The dynamic range of the air factor ofthe conversion system during a run was 10:1. The empiricalstoichiometry of conversion gas during a run was CH_3.1O:CH₀O₀. Finally ,this experimental series revealed one ofthe main reasons why fuel wood is more difficult to burn thanfor example wood pellets. The relatively dry fuel wood (12-31g/m₂,s) displayed a significantly lower time-integratedmean of mass flux of conversion gas than both the wood pellets(37-62 g/m₂,s) and the wood chips (50-90 g/m₂,s). The higher the mass flux of conversion gasproduced in the conversion system, the higher the combustiontemperature for a given combustion system, which in turn ispositively coupled to the combustion efficiency.</p><p>In future work the method will be improved so thatmeasurements of combustion efficiency can be carried out. Othertypes of conversion concepts will be studied by the method.</p><p>Keywords: Packed-bed combustion, thermochemical conversionof biomass, solid-fuel combustion, fuel-bed combustion, gratecombustion, biomass combustion, gasification, pyrolysis,drying.</p>