La Tesis Doctoral estudia la observaci'on en tiempo real de la concentraci'on en el colector de escape de 'oxidos de nitr'ogeno (NOx) y del dosado en motores diesel sobrealimentados (¿ '1 ). Para ello se combinan dos fuentes de informaci'on diferentes: ¿ Sensores capaces de proporcionar una media de dichas variables, ¿ y modelos orientados a control que estiman estas variables a partir de otras medidas del motor. El trabajo parte de la evaluaci'on de la precisi'on de los sensores, realizada mediante la comparaci'on de su medida con la proporcionada por equipos anal'¿ticos de alta precisi'on, que son usados como est'andares de calibraci'on est'atica. Tambi'en se desarrollan en la Tesis m'etodos para la calibraci'on de la din'amica del sensor; dichos m'etodos permiten identi¿car un modelo de comportamiento del sensor y revelar su velocidad de respuesta. En general, estos sensores demuestran ser precisos pero relativamente lentos. Por otra parte, se proponen modelos r'apidos para la estimaci'on de NOx y ¿ '1 . Estos m'etodos, basados en relaciones f'¿sicas, tablas de par'ametros y una serie de correcciones, emplean las medidas proporcionadas por otros sensores con el ¿n de proporcionar una estimaci'on de las variables de inter'es. Los modelos permiten una estimaci'on muy r'apida, pero resultan afectados por efectos de deriva que comprometen su precisi'on. Con el ¿n de aprovechar las caracter'¿sticas din'amicas del modelo y mantener la precisi'on en estado estacionario del sensor, se proponen t'ecnicas de fusi'on de la informaci'on basadas en la aplicaci'on de ¿ltros de Kalman (KF). En primer lugar, se dise¿na un KF capaz de combinar ambas fuentes de informaci'on y corregir en tiempo real el sesgo entre las dos se¿nales. Posteriormente, se estudia la adaptaci'on en tiempo real de los par'ametros del modelo con el ¿n de corregir de forma autom'atica los problemas de deriva asociados al uso de modelos. Todos los m'etodos y procedimientos desarrollados a lo largo de la presente Tesis Doctoral se han aplicado de forma experimental a la estimaci'on de NOx y ¿ '1 . De forma adicional, la Tesis Doctoral desarrolla aspectos relativos a la transferencia de estos m'etodos a los motores de serie. / The dissertation covers the problem of the online estimation of diesel engine exhaust concentrations of NOx and '1. Two information sources are utilised: ¿ on-board sensors for measuring NOx and '1, and ¿ control oriented models (COM) in order to predict NOx and '1. The evaluation of the static accuracy of these sensors is made by comparing the outputs with a gas analyser, while the dynamics are identified on-board by perform- ing step-like transitions on NOx and '1 after modifying ECU actuation variables. Different methods for identifying the dynamic output of the sensors are developed in this work; these methods allow to identify the time response and delay of the sensors if a sufficient data set is available. In general, these sensors are accurate but present slow responses. Afterwards, control oriented models for estimating NOx and '1 are proposed. Regarding '1 prediction, the computation is based on the relative fuel-to-air ratio, where fuel comes from an ECU model and air mass flow is measured by a sensor. For the case of NOx, a set-point relative model based on look-up tables is fitted for representing nominal engine emissions with an exponential correction based on the intake oxygen variation. Different corrections factor for modeling other effects such as the thermal loading of the engine are also proposed. The model is able to predict NOx fast with a low error and a simple structure. Despite of using models or sensors, model drift and sensor dynamic deficiencies affect the final estimation. In order to solve these problems, data fusion strategies are proposed by combining the steady-state accuracy of the sensor and the fast estimation of the models by means of applying Kalman filters (KF). In a first approach, a drift correction model tracks the bias between the model and the sensor but keeping the fast response of the model. In a second approach, the updating of look-up tables by using observers is coped with different versions based on the extended Kalman filter (EKF). Particularly, a simplified KF allows to observe the parameters with a low computational effort. Finally, the methods and algorithms developed in this work are combined and applied to the estimation of NOx and '1. Additionally, the dissertation covers aspects relative to the implementation of the methods in series engines. / Blanco Rodríguez, D. (2013). Modelling and observation of exhaust gas concentrations for diesel engine control [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/32666 / TESIS / Premios Extraordinarios de tesis doctorales

[pt] Os semicondutores à base de TiO2 atualmente em desenvolvimento na área de fotodegradação de poluentes apresentam limitações para viabilização comercial. Os desafios encontrados são, i) tornar mais eficiente a absorção de luz na faixa visível para fotogeração dos pares elétrons livres e buracos, ii) elevação da área superficial e iii) redução da taxa de recombinação elétrons livres-buracos. Este estudo focou na síntese e caracterização de um novo nanohíbrido, sensível a luz visível à base de nanofolhas de ferrititanato esfoliadas e de nanopartículas de TiO2 (anatásio) conjugadas com acetilacetona (ACAC), controlando a razão molar de titânio nos dois componentes, além de abordar diferentes rotas de síntese do nanohíbrido e estudar os componentes separadamente. Os nanohíbridos foram sintetizados pelas rotas de mistura física e de química branda sendo nomeados como MF e HM-1 respectivamente, considerando as razões molares de [Ti]anatásio/[Ti]ferrititanato de 10, 5 e 2. Todos os nanohíbridos apresentaram elevada área superficial (superior a 100 m2/g) e restauração parcial da estrutura pilarizada. Os nanohíbridos com maior razão molar de [Ti]anátasio/[Ti]ferrititanato apresentaram maior eficiência de foto-oxidação dos gases poluentes NOx, bem como a MF apresentou maior eficiência que a HM-1. O nanohíbrido com melhor desempenho, a MF de razão 10, obteve uma conversão após 5 min de aproximadamente 80 por cento e apresentou redução gradativa de conversão até 25 por cento após 2h. Contudo, o componente isolado TiO2-ACAC calcinado a 300 graus C promoveu a sensibilização do anatásio em todo o espectro visível, tendo área superficial de 137 m2/g e uma conversão do NOx superior a 95 por cento, com redução gradativa da conversão até 38,5 por cento após 2h. Os resultados do anatásio modificado podem ser compreendidos pela combinação da estrutura nanométrica, da elevada área superficial e, principalmente, pela presença de ligações de titânia com acetilacetona superficiais em monocamadas maximizando e estabilizando a fotogeração de pares elétrons/buracos. Enquanto odesempenho inferior dos nanohíbridos pode ser atribuído a presença devacâncias de oxigênio e íons de Fe3+ atuando como centros de recombinação reduzindo a formação de radicais oxidantes. / [en] Currently, the development of TiO2-based semiconductors carry out drawback at photocatalytic commercial applications for photodegradation of pollutants gases. The photocatalytic limitations are i) inefficient absorption of visible light that inhibits the photogeneration of free electron and hole pairs, ii) small surface area and iii) high rate of electron to hole recombination. The aim of this study was the synthesis and characterization of a new visible light sensitive nanohybrids based on ferrititanate exfoliated nanosheets and a charge transfer complex (TiO2-ACAC) by controlling the [Ti] anatase/[Ti] ferrititanate molar ratio and applying two different synthesis route. Besides, it was studied the individual components. The nanohybrids were synthesized through physical mixture route and soft chemical route, named respectively as MF and HM-1. The molar ratios used in this work were 10, 5 and 2. All of the heterostructures presented high surface area (higher than 100m2/g) and partial restacking of lamellar structure. The nanohybrids with higher molar ratio and synthesized through physical mixture showed the greatest photocatalytic activity with more efficient photo-oxidation of gas NOx than the nanohybrids synthesized through soft chemical route. The nanohybrid with better performance, the MF with ratio 10, obtained a NO conversion of approximately 80 percent after 5min and gradual reduction of conversion to 25 percent after 2h. Nevertheless, the TiO2-ACAC nanoparticles component calcined at 300 C degrees presented total sensitivity at the range of visible light, surface area of 137m2/g and conversion higher than 95 percent with partial photocatalytic deactivation to 38.5 percent after 2h. The results of TiO2-ACAC system studied can be described due to its nanometric structure, high surface area and, mainly, for the presence of strongly interacting between acetylacetone with Ti ions from anatase surface, while maximized and stabilized the photogeneration of electron-hole pairs and reactive oxidizing species (ROS), .O2 -. However, the lower performance of the nanohybrids ascribed to the oxygen vacancies and Fe3+ ions that acting as electron trapping center reducing the formation of ROS.

In the last few decades India has advanced socioeconomically due to the rapid growth of industries and automobile sector. This in turn increases the use of fossil fuel and diesel. The atmosphere gets polluted due to the harmful substances, which comes from the burning of fuel. These pollutants can be in the form of gaseous, liquid or solid particulate. Diesel engines, the major source of power in industries and automobiles, play a significant part in causing air pollution. The major pollutants in diesel exhaust are oxides of nitrogen (NOX), sulphur dioxide (SO2), carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), volatile organic compounds (VOC), aldehydes and alcohols. Due to the heavy consumption of diesel as a fuel there is an urgent need to control diesel exhaust. Diesel exhaust is a complex mixture of several gases and fine particles (commonly known as soot) that contains more than 40 toxic air contaminants. Amongst the gaseous pollutants in diesel exhaust, the major concern and a challenging task is to control oxides of nitrogen, commonly referred to as NOX as it is the major contributor for acid rain, photochemical smog etc. Successful control of emissions from diesel engines is yet to be achieved. The conventional techniques which are available to control emission now are either difficult to operate or does not satisfy the stringent emission standards. This has made the researchers throughout the world to find an alternative and effective non-conventional after treatment technique to reduce diesel engine emission. The failure of conventional techniques lead to the development of non-conventional techniques such as high voltage electric discharge based plasma which has already been proved to be economical and highly efficient in industrial electrostatic precipitators. Electric discharge plasma or non-thermal plasma produce energetic electrons which react with background molecules in flue gas leading to active species such as radicals. These radicals being chemically active selectively react with the harmful pollutants facilitating their removal/reduction. The present thesis work is an attempt to provide a technical solution to achieve higher removal efficiencies of oxides of nitrogen in the backdrop of shortcomings that exist in conventional technologies to do so. The current thesis describes the research in four stages: (i) studies on NOX removal from diesel exhaust by cross-flow DBD reactor, where design and fabrication of cross-flow DBD reactor, exhaust treatment using cross-flow DBD reactor and exhaust treatment with cascaded plasma-adsorbent technique is described (ii) studies on NOX removal from diesel exhaust by compact discharge plasma sources, where design and fabrication of high frequency high voltage AC (HVAC) using old television flyback transformer, Design and fabrication of high voltage pulse (HVPulse) using automobile ignition coil, exhaust treatment with both HVPulse and HVAC and exhaust treatment with cascaded plasma-adsorbent technique is described (iii) studies on NOX removal from diesel exhaust using solar powered discharge plasma source is described (iv) studies on the NOX removal from diesel exhaust using red mud, where exhaust treatment with red mud and Exhaust treatment cascaded plasma-red mud is covered. The results have been discussed in light of enhancing the NOX removal efficiency for stationary and automobile engine exhausts.

Denna fallstudie undersöker hur två marina system för rening av kväveoxider från rökgaser, EGR samt SCR, presterar med avseende på emissioner och ekonomi. En vanligt förekommande tvåtakt dieselmotor valdes att teoretiskt utrustas med respektive system där ett beräkningsprogram, CEAS, kunde användas för att genomföra beräkningar efter valda driftsförhållanden och därmed få ut relevant data. Med förbrukning av de för systemen erforderliga kemikalierna samt förbrukning av bränsle kunde kostnader beräknas efter inhämtande av priser. Med IMO:s Tier III-krav som mål kunde förhindrad mängd utsläppt NOX beräknas och med hjälp av bildad rökgasmängd vid användande med och utan system kunde en uppfattning fås om hur systemen påverkar fartygets emissioner. Beräkningar valdes att göras över en uppskattad livslängd för ett fartyg, 20 år. Vidare valdes de ekonomiska kostnaderna för systemen att slås samman med inköpspriset för systemen. Slutsatser som kunde tas från studien var bland annat att SCR är det system vars sammanräknade kostnad är lägst vid drift. EGR är en teknik som utöver att klara Tier III-kraven även medför en minskning av en del andra miljöförorenande ämnen. Studien antyder att EGR är det bättre systemet ur emission synpunkt och SCR är det bättre systemet sett till ekonomi. / This case study examines how two marine systems used for reduction of nitrogen oxides from exhaust gases, EGR and SCR, performs in terms of emissions and economic impact. A commonly used two-stroke diesel engine was chosen to be, in theory, equipped with each system. By using a calculation program, CEAS, calculations based on different running conditions were possible and thereby obtain relevant data. With the given consumption of chemicals for each system and the consumption of fuel, costs were able to be calculated after price data was retrieved. With IMO’s tier III regulation as the limit, the inhibited amount of released NOX could be calculated. By using data of produced amounts of exhaust gases, with and without the systems, an estimate could be made on how the systems affect the ship emissions. Calculations were based on an approximation of a vessels lifespan, 20 years. Furthermore, the economic cost for each system was added with the purchase price of each system. Conclusions that could be drawn from the study were, amongst other things, that SCR was the system with the lowest operational cost. EGR does, besides being able to manage the Tier III-requirement, also manage to reduce some other environmental hazardous substances. The study implies that EGR is the better system when viewed in terms of emissions and SCR is the better system when viewed in terms of economy.

O processo Humifert é uma alternativa para produção de compostos fertilizantes fosfatados, com solubilização mais lenta do que os fertilizantes tradicionais, resultando em um tempo de nutrição da planta maior. No processo, utilizam-se rochas fosfáticas com algum tipo de limitação para o aproveitamento normal, seja pelos teores menores, seja por dificuldades de tratamento industrial dos minérios, além de materiais orgânicos. O objetivo deste trabalho foi melhorar o equipamento existente no Instituto de Geociências, para tornar possível condições de produção de NOx, no Processo Humifert, capaz de produzir um teor de fósforo disponibilizado em condições controladas de processo. Empregando-se planejamento estatístico de experimentos foi possível selecionar as variáveis de entrada mais importantes ao processo (agitação da mistura de rocha fosfática, matéria orgânica e umidade, A codificada; temperatura de oxidação da amônia, B codificada; umidade da mistura, C codificada; porosidade da placa difusora, D codificada; vazão do ar auxiliar, E codificada). A análise estatística, também, permitiu construir modelos de regressão nos quais as influências das variáveis de processo foram sentidas na solubilidade do fósforo nos extratores: ácido cítrico, solução 2% (Pácido cítrico); água, (Págua); citrato neutro de amônio mais água, (PCNA+água). Estas últimas variáveis aqui denominadas de variáveis de saída ou de resposta. A manipulação dos referidos modelos permite obter o fertilizante de acordo com as necessidades da cultura e do solo. O estudo, também, permitiu concluir que a maior quantidade de fósforo disponível nos compostos organofosfatados foi o solúvel em ácido cítrico, portanto, a maior quantidade de compostos gerados encontra-se na melhor condição de disponibilidade pela planta. / Humiphert process is an alternative used for producing phosphated compound fertilizers with a slower solubilization when compared to other traditional fertilizers, resulting in a longer period of plant nutrition. During the process, phosphatic rocks are used along with some sort of limitation according to the normal development, both by their lower content percentage and by treatment of difficulties of industrial ores, besides organic materials. This work aim to improve an equipment existing at the Instituto de Geociências in order to find out the best process condition to produce NOX in Humifert process. This way, the process is able to produce an available phosphorus content under process conditions controlled. The process variables were select by using of experimental design. These variables were: agitation of phosphatic rock mixture (rock, organic material and humidity), A coded; ammonia oxidation temperature, B coded; humidity of mixture, C coded; porosity of the diffusing board, D coded; auxiliary air, E coded. Statistical analysis also allowed to build regression models in which the influences of process variables were felt in the solubility of phosphorus in the extractors: 2% solution of citric acid (Pacid Citric), water (Pwater); ammonium neutral citrate plus water (PCNA + water). These last variables here called output variable or response. The manipulation of these models allows to obtain the fertilizer according to the needs of the crop and soil. The study still conclude that the greater amount of available phosphorus in compound was soluble in citric acid, therefore, a greater amount of compounds generated is in the best condition of availability for the plant. The study still conclude that the greater amount of available phosphorus in the organophosphated compounds were soluble in citric acid. Therefore, the greater amount of compounds generated is in the best condition of availability for the plant.

O processo Humifert é uma alternativa para produção de compostos fertilizantes fosfatados, com solubilização mais lenta do que os fertilizantes tradicionais, resultando em um tempo de nutrição da planta maior. No processo, utilizam-se rochas fosfáticas com algum tipo de limitação para o aproveitamento normal, seja pelos teores menores, seja por dificuldades de tratamento industrial dos minérios, além de materiais orgânicos. O objetivo deste trabalho foi melhorar o equipamento existente no Instituto de Geociências, para tornar possível condições de produção de NOx, no Processo Humifert, capaz de produzir um teor de fósforo disponibilizado em condições controladas de processo. Empregando-se planejamento estatístico de experimentos foi possível selecionar as variáveis de entrada mais importantes ao processo (agitação da mistura de rocha fosfática, matéria orgânica e umidade, A codificada; temperatura de oxidação da amônia, B codificada; umidade da mistura, C codificada; porosidade da placa difusora, D codificada; vazão do ar auxiliar, E codificada). A análise estatística, também, permitiu construir modelos de regressão nos quais as influências das variáveis de processo foram sentidas na solubilidade do fósforo nos extratores: ácido cítrico, solução 2% (Pácido cítrico); água, (Págua); citrato neutro de amônio mais água, (PCNA+água). Estas últimas variáveis aqui denominadas de variáveis de saída ou de resposta. A manipulação dos referidos modelos permite obter o fertilizante de acordo com as necessidades da cultura e do solo. O estudo, também, permitiu concluir que a maior quantidade de fósforo disponível nos compostos organofosfatados foi o solúvel em ácido cítrico, portanto, a maior quantidade de compostos gerados encontra-se na melhor condição de disponibilidade pela planta. / Humiphert process is an alternative used for producing phosphated compound fertilizers with a slower solubilization when compared to other traditional fertilizers, resulting in a longer period of plant nutrition. During the process, phosphatic rocks are used along with some sort of limitation according to the normal development, both by their lower content percentage and by treatment of difficulties of industrial ores, besides organic materials. This work aim to improve an equipment existing at the Instituto de Geociências in order to find out the best process condition to produce NOX in Humifert process. This way, the process is able to produce an available phosphorus content under process conditions controlled. The process variables were select by using of experimental design. These variables were: agitation of phosphatic rock mixture (rock, organic material and humidity), A coded; ammonia oxidation temperature, B coded; humidity of mixture, C coded; porosity of the diffusing board, D coded; auxiliary air, E coded. Statistical analysis also allowed to build regression models in which the influences of process variables were felt in the solubility of phosphorus in the extractors: 2% solution of citric acid (Pacid Citric), water (Pwater); ammonium neutral citrate plus water (PCNA + water). These last variables here called output variable or response. The manipulation of these models allows to obtain the fertilizer according to the needs of the crop and soil. The study still conclude that the greater amount of available phosphorus in compound was soluble in citric acid, therefore, a greater amount of compounds generated is in the best condition of availability for the plant. The study still conclude that the greater amount of available phosphorus in the organophosphated compounds were soluble in citric acid. Therefore, the greater amount of compounds generated is in the best condition of availability for the plant.

<p>A new NO_x sensor for high-temperature applications has been developed and thouroghly characterised. The sensor layers are a mixed oxide of CoO, MgO and MgO₂ deposited by thermal evaporation with a porous platinum gate on top, deposited by thermal evaporation or sputtering. The sensitivity and selectivity of the sensor is promising and is shown to depend upon the ratio between Co and Mg in the film and a number of competing mechanisms are shown to take place on the sensor surface. Response and recovery of the device is still slow and there are some drift, which are suggested to be due to a restructuring sensor surface during operation that was found by SEM-studies. Finally,the oxide surface has been characterized by XPS and a novel process for deposition of the sensor layers by lift-off technique has been developed.</p>

Intresset för biobränsleproducerad energi har ökat i takt med att kunderna blivit mer miljömedvetna. På grund av detta har efterfrågan på briketter ökat samtidigt som träindustrin har haft det svårt i en sviktande konjunktur. Därför har ett examensarbete utförts i samarbete med E.ON Värme Sverige AB där undersökningar på bränslebyte i pannor avsedda för torra bränslen till fuktigare, stamvedflis har utfört. För denna undersökning har begränsningar införts på övre och undre effekt i form av uppehållstid och slutförbränningstemperatur. Intervallen är enbart beräknade på stamvedflis med 30 och 40 % fukthalt. Undersökning visar att det går bra att elda stamvedsflis i briketteldade pannor utan att emissionerna ökar så pass mycket att villkoren för anläggningarna överskrids om lasten hålls inom vissa intervall. Det möjliga effektintervallet ökar med minskad fukthalt på bränslet. Undersökningen har visat att det är bränslets kvalitet som är den mest begränsande faktorn. / The interest in bioenergy has increased with increased environmental awareness. The increasing demand on biofuels and the decreasing availability of the rawmaterials for making refined biofuels such as wood briquettes and wood pellets have caused the prices of these biofuels to increase. This report is performed in collaboration with E.ON Värme Sverige AB and its purpose is to investigate the possibilities for a change of fuels in existing boilers designed for refined biofuels, from wood briquettes to wood chips. To be able to calculate a power interval where it would be possible to use wood chips with moisture contents of 30 and 40% by weight respectively, we had to make some assumptions regarding maximum flue gas flow, minimum retention time and the lowest temperature regarding complete combustion of CO. Our calculations show that it is possible to use woodchips with a moisture content of 30 % w/w without any significant problems in all our boilers. When the moisture content is increased to 40 % w/w the interval for possible power output becomes more narrow. The amount of dust that is being emitted from the boilers does not exceed the limits regulated by environmental law, unless the thermal load of the boiler is too high. The single most important factor for a successful change of fuel from wood briquettes to woodchips is that the fuel quality is good.

A new NOx sensor for high-temperature applications has been developed and thouroghly characterised. The sensor layers are a mixed oxide of CoO, MgO and MgO2 deposited by thermal evaporation with a porous platinum gate on top, deposited by thermal evaporation or sputtering. The sensitivity and selectivity of the sensor is promising and is shown to depend upon the ratio between Co and Mg in the film and a number of competing mechanisms are shown to take place on the sensor surface. Response and recovery of the device is still slow and there are some drift, which are suggested to be due to a restructuring sensor surface during operation that was found by SEM-studies. Finally,the oxide surface has been characterized by XPS and a novel process for deposition of the sensor layers by lift-off technique has been developed.

<p>Intresset för biobränsleproducerad energi har ökat i takt med att kunderna blivit mer miljömedvetna. På grund av detta har efterfrågan på briketter ökat samtidigt som träindustrin har haft det svårt i en sviktande konjunktur. Därför har ett examensarbete utförts i samarbete med E.ON Värme Sverige AB där undersökningar på bränslebyte i pannor avsedda för torra bränslen till fuktigare, stamvedflis har utfört.<strong></strong></p><p>För denna undersökning har begränsningar införts på övre och undre effekt i form av uppehållstid och slutförbränningstemperatur. Intervallen är enbart beräknade på stamvedflis med 30 och 40 % fukthalt.</p><p>Undersökning visar att det går bra att elda stamvedsflis i briketteldade pannor utan att emissionerna ökar så pass mycket att villkoren för anläggningarna överskrids om lasten hålls inom vissa intervall. Det möjliga effektintervallet ökar med minskad fukthalt på bränslet.</p><p>Undersökningen har visat att det är bränslets kvalitet som är den mest begränsande faktorn.</p> / <p>The interest in bioenergy has increased with increased environmental awareness. The increasing demand on biofuels and the decreasing availability of the rawmaterials for making refined biofuels such as wood briquettes and wood pellets have caused the prices of these biofuels to increase. This report is performed in collaboration with E.ON Värme Sverige AB and its purpose is to investigate the possibilities for a change of fuels in existing boilers designed for refined biofuels, from wood briquettes to wood chips.</p><p>To be able to calculate a power interval where it would be possible to use wood chips with moisture contents of 30 and 40% by weight respectively, we had to make some assumptions regarding maximum flue gas flow, minimum retention time and the lowest temperature regarding complete combustion of CO.</p><p>Our calculations show that it is possible to use woodchips with a moisture content of 30 % w/w without any significant problems in all our boilers. When the moisture content is increased to 40 % w/w the interval for possible power output becomes more narrow. The amount of dust that is being emitted from the boilers does not exceed the limits regulated by environmental law, unless the thermal load of the boiler is too high.</p><p>The single most important factor for a successful change of fuel from wood briquettes to woodchips is that the fuel quality is good.<strong></strong></p>