Abstract

This study investigates the esterification of hydrolyzed sea mango (Cerbera odollam) oil using several cationic ion exchange resins. The best resins were selected based on their performance in a preliminary esterification process. The best resins were then subsequently used in the optimization of the process parameters. The esterification parameters studied were reaction temperature (40–160°C), reaction time (0–5 h), molar ratio of oil to methanol (0.5:1 to 1:14), and catalyst loading (1–14 wt%). Among the resins studied, Amberlyst 15 was found to be the most promising catalyst in the esterification of the hydrolyzed sea mango oil. Moderate reaction temperatures, 60–100°C, were found to be adequate in converting the hydrolyzed sea mango oil into esters. Further investigation revealed that the esterification reaction using the cationic ion exchange resins proceeds at a fast rate, whereby fatty acid methyl esters (FAME) yield of over 80% at moderate reaction temperature was achievable in less than 1 h of reaction time. Small amount of catalyst, which is less than 5 wt%, was also found to be sufficient in catalyzing the esterification process to an acceptable yield.

Abstract

The need for sustainable biofuels has initiated a global search for innovative technologies that can sustainably convert nonfood bioresources to liquid transportation fuels. While 2nd generation cellulosic ethanol has begun to address this challenge, other resources including yellow and brown grease are rapidly evolving commercial opportunities that are addressing regional biodiesel needs. This review examines the technical and environmental factors driving the collection of trap FOG (Fats, Oils, and Greases), its chemical composition and technologies currently available and future developments that facilitate the conversion of FOG into biodiesel.

Abstract

Ultrasound-assisted transesterification of refined palm oil (RPO) and crude palm oil (CPO) to produce biodiesel using a palm oil mill fly ash supported calcium oxide (CaO) catalyst is studied in this work. The reaction time is significantly reduced from a maximum of 360 min under conventional mixing to just 30 min with the use of ultrasound. Under ultrasonic cavitation, the required catalyst loading and methanol to oil molar ratio to produce comparable yields and fatty acid methyl esters (FAME) conversions as conventional mixing are lower. For RPO, the ultrasound-assisted transesterification conditions of 60% ultrasonic amplitude, 30 min reaction time, 4 wt.% catalyst loading, and 9:1 methanol to oil molar ratio result in maximum biodiesel yield and FAME conversion of 85.23% and 97.02%, respectively. As for CPO, maximum biodiesel yield of 73.23% and FAME conversion of 97.04% are obtained under the same conditions with the exception of a methanol to oil molar ratio of 12:1. Key physicochemical properties of the produced biodiesels are found to be within the limits set by EN 14214 and ASTM D 6751. Catalyst reusability tests indicate that the catalyst can be used up to three consecutive cycles after regeneration using methanol washing followed by recalcination at 850°C for 2 h.

Abstract

Finland has set ambitious long-term targets, which aim to reduce greenhouse gas emissions from the transport sector and the whole energy system by 2050. By utilising the energy system model STREAM, which includes the power, heat and transport sectors, this paper develops two alternative scenarios for the transport sector by 2050—one with a high percentage of electric vehicles (EV) and another with a high percentage of biofuels (BIO), and compares the scenario results with a known Carbon-Neutral Scenario (CNS) which is adopted from the Nordic Energy Technology Perspective (IEA in Nordic energy technology perspective—pathways to a carbon-neutral energy future, 2013a). The socio-economic value of the total system cost is computed and the system integration of the transport sector with the electricity and heating sectors is simulated with an hourly time resolution. This study finds that a Finnish transport sector with a high share of EV by 2050 leads to the lowest total annual system cost of the scenarios and yields a reduction by 2.3% compared to CNS. While the transport configuration in the BIO scenario achieves the highest total annual system cost which is 0.4% higher than CNS. The robustness of the results is tested through a sensitivity analysis which shows that the costs (investment and maintenance) of biodiesel cars and EV are the most sensitive parameters in the comparative analysis of the scenarios. Document type: Part of book or chapter of book

Abstract

The ever growing human population and the corresponding economic development of mankind have caused a relentless surge in the energy demand of the world. The fast diminishing fossil fuel reserves and the overdependence of petroleum based fuels have already prompted the world to look for alternate sources of energy to offset the fuel crisis in the future. Waste Cooking Oil Methyl Ester (WCOME) has proven itself as a viable alternate fuel that can be used in Compression Ignition (CI) engines due to its low cost, non-toxicity, biodegradability and renewable nature. It also contributes a minimum amount of net greenhouse gases, such as CO2, SO2 and NO emissions to the atmosphere. The main objective of this paper is to focus on the study of the performance, combustion and emission parameters of CI engines using WCOME and to explore the possibility of utilizing WCOME blends with diesel extensively in place of diesel. The production methods used for transesterification play a vital role in the physiochemical properties of the methyl esters produced. Various production intensification technologies such as hydrodynamic cavitation and ultrasonic cavitation were employed to improve the yield of the methyl esters during transesterification. This review includes the study of WCOME from different origins in various types of diesel engines. Most of the studies comply with the decrease in carbon monoxide (CO) emissions and the increase in brake thermal efficiency while using WCOME in CI engines. Many researchers reported slight increase in the emissions of oxides of nitrogen. ANN modeling has been widely used to predict the process variables of the diesel engine while using WCOME. The versatility of ANN modeling was proven by the minimum error percentages of the actual and predicted values of the performance and emission characteristics.

Abstract

Sweden has the goal of reaching a fossil independent transportation sector by 2030. Two ways to reach the goal is to increase the use of electric vehicles or produce more biofuels. Both alternatives could be powered by forest residue, which is an underutilized resource in the country. Electricity could be produced in a biomass fired Combined Heat and Power (CHP) plant, and biofuel could be produced in a biorefinery through gasification of biomass and Fischer-Tropsch process. When located in Stockholm County, both system can also distribute heat to the district heating system. It is however important to use the biomass in an energy-efficient way. The scope of this work has been to analyze the efficiency together with environmental and economic aspects of the two systems.  To assess the efficiency and environmental impact of the two systems a forest to wheel study was made of the systems where the product was studied from harvesting of forest residue to driving the vehicle. The studied functional units were: kilometers driven by vehicle, kWh of district heating, CO2-equivalents of greenhouse gases and MWh of forest residue. The system using CHP technology and electric vehicles outperformed the biorefinery system on the two first functional units. Using the same amount of forest residue more than twice as much district heating and almost twice as many driven kilometers were produced in this system. The study also showed that both systems avoids significant greenhouse gas emissions and can be part of the solution to decrease emissions from road transportation.  The profitability of investing in a CHP plant or a biorefinery was calculated through the net present value method. It showed that the expected energy prices are too low for the investments to be profitable. The CHP plant investment has a net present value of -1.6 billion SEK and the biorefinery investment has a net present value of -4.6 billion SEK. Furthermore, the biorefinery investment entails higher risk due to the high investment cost and uncommercialized technology. Both systems face barriers for implementation, these barriers have been studied qualitatively.  Sverige har som mål att skapa en fossiloberoende fordonsflotta till år 2030. Två vägar som pekats ut för att nå målet är att öka användningen av eldrivna fordon eller att producera mer biobränsle. Båda alternativen kan drivas av skogsavfall, en råvara som det finns gott om i Sverige. Elektricitet kan produceras av skogsavfallet i ett kraftvärmeverk, och biobränsle i ett bioraffinaderi genom användning av förgasning och Fischer-Tropschmetoden. I Stockholms län skulle båda systemen dessutom kunna producera värme till Stockholms fjärrvärmesystem. Det är dock viktigt att använda skogsavfallet på ett resurseffektivt sätt. Därför undersöker detta arbete effektiviteten av de två olika systemen tillsammans med en analys av växthusgasutsläpp och ekonomiska förutsättningar.  För att kunna utvärdera effektiviteten och klimatpåverkan av de två olika systemen utfördes en ”skog-till-hjul”-analys där produkten undersöktes från ursprunget, till drivandet av ett fordon. För att utföra studien definierades fyra funktionella enheter. De funktionella enheterna var: körsträcka med bil mätt i kilometer, kWh fjärrvärmeproduktion, CO2 ekvivalenter av växthusgasutsläpp och MWh skogsavfall. Studien visade att systemet där skogsavfallet används i ett kraftvärmeverk för att producera elektricitet och ladda elbilar hade bättre resultat i de två första funktionella enheterna. Systemet producerade nästan dubbelt så lång körsträcka och mer än dubbelt så mycket fjärrvärme som systemet där skogsavfallet används i ett bioraffinaderi och biobränslet används i dieselbilar. Studien visade även att båda system kan bidra till att sänka växthusgasutsläppen från transportsektorn.  Lönsamheten att investera i ett kraftvärmeverk eller bioraffinaderi beräknades med nuvärdesmetoden. Studien visade att de förväntade framtida energipriserna är för låga för att investeringarna ska bli lönsamma. Kraftvärmeanläggningen hade ett nuvärde på -1.6 miljarder kronor, och bioraffinaderiet ett nuvärde på -4.6 miljarder kronor. Dessutom ansågs investeringen i ett bioraffinaderi vara en hög risk på grund av den höga investeringskostnaden och att tekniken idag inte är kommersialiserad. Det finns även en rad andra barriär för att genomföra de två olika systemen, dessa barriärer har studerats kvalitativt i arbetet. 

Abstract

Tese de doutoramento em Sistemas Sustentáveis de Energia, apresentada ao Departamento de Engenharia Mecânica da Faculdade de Ciências e Tecnologia da Universidade de Coimbra The controversy raised around biofuels sustainability increased the pressure on biodiesel producers to be as cost efficient as possible and, simultaneously, ensure the sustainability of the biodiesel. As about 85% of biodiesel production costs are attributed to feedstock cost and each feedstock has a different environmental profile, operational level decision making about feedstock selection is crucial to reduce production costs and manage biodiesel environmental performance. This thesis explores opportunities to improve biodiesel cost effectiveness at the operational level, particularly in the feedstock selection process, by assessing the use of waste-based feedstocks (Waste Cooking Oil, WCO) in blends with conventional feedstocks (palm, rapeseed and soya) and hedging feedstock purchase, whilst managing environmental impacts. For this purpose, an uncertainty-aware decision aiding tool to assess economic and environmental tradeoffs of decisions at the operational level, addressing feedstock compositional and price uncertainty, was developed. The model combines environmental life-cycle assessment (LCA) with blending models using multi-objective optimization to assess water scarcity (WSI), water degradability – acidification (AA), eutrophication (EU), ecotoxicity (FT) and human toxicity (HT) – and Greenhouse Gas (GHG) emissions (CC). Data from different crop cultivation locations were considered: Colombia and Malaysia for palm; Argentina, Brazil and the United States (US) for soybean; and, Germany, France, Spain, Canada and the US for rapeseed. An approach was developed to facilitate the decision process that enables the decision-maker to select the best compromise feedstock blend based on an explicit overall environmental performance. Results show that incorporating feedstocks’ compositional uncertainty allows the use of WCO in blends with conventional feedstocks without compromising biodiesel technical performance. A reduction of total feedstock cost was obtained for blends with WCO relatively to equivalent (similar technical performance) blends composed only of virgin oils. The percentage of cost reduction depends on the relation among the prices of the feedstocks. Moreover, the use of WCO in the blends allows a reduction in cost variation reduction relatively to virgin oils blends because the price of that feedstock presents lower volatility comparatively to the conventional feedstocks. The differences observed in the environmental assessment of the various virgin oils systems are mainly related to water scarcity of the location, and the fertilization and pesticides schemes used in each crop/location. Results show that higher water scarcity footprint are due to both high water consumption and high water scarcity of the cultivation site. For the toxicity categories (HT and FT), the highest values are ascribed to the high quantity of pesticide used in the cultivation, while for CC, AA and EU the main contributor is the quantity of fertilizers. WCO presents the lowest values WSI, CC, EU and AA. The multi-objective analysis showed that lower CC and WSI solutions (blends) can be obtained at a lower cost if WCO is included in the biodiesel blend. The same conclusion is obtained when more environmental objectives (AA, EU, FT and HT) are considered in the analysis. The decision-aiding approach developed allows for the visualization of the tradeoff between cost and environmental impacts, facilitating the decision process when more than three objectives are at stake. This research shows that the inclusion of WCO in a diversified portfolio of feedstocks used in blending optimization models is an attractive approach to improve biodiesel cost effectiveness and environmental performance. The model developed can be further used to optimize the blending of alternative feedstocks and to assess the technical viability of other waste-based feedstock (e.g. animal fat) or emerging feedstocks such as algae. Although the tool was designed specifically for biodiesel production system, it can be adapted to other industries, particularly in the recycling sector, to support production planning at the operational level to enhance technical, economic and environmental performance of these industries. A controvérsia gerada em torno da sustentabilidade dos biocombustíveis aumentou a pressão nos produtores de biodiesel para serem o mais eficientes possível em termos de custos e, simultaneamente, garantirem a sustentabilidade do biodiesel. Como cerca de 85% do custo total de produção é atribuído ao custo da matéria-prima, e cada uma apresenta um perfil ambiental diferente, decisões ao nível operacional acerca de selecção de matéria-prima são cruciais para melhorar a performance económica e ambiental do biodiesel. Esta tese explora estratégias para reduzir custos de produção de biodiesel, particularmente no processo de selecção de matérias-primas, ao avaliar o uso de resíduos (Óleo Alimentar Usado, OAU) em misturas com óleos convencionais (soja, palma, colza) e planear a compra de matéria-prima, e, simultaneamente, gerir os impactes ambientais. Para tal, foi desenvolvida uma ferramenta de apoio à decisão para avaliar compromissos económicos e ambientais de decisões efectuadas ao nível operacional. Esta ferramenta tem em conta a incerteza associada à composição e ao preço da matéria-prima. O modelo desenvolvido combina Avaliação de Ciclo de Vida (ACV) ambiental com algoritmos de mistura através de optimização multiobjectivo para avaliar a escassez de água (WSI), degradabilidade da água – acidificação (AA), eutrofização (EU), ecotoxicidade (FT) e toxicidade humana (HT) – e, emissões de gases com efeito de estufa (CC). Diferentes locais de cultivo foram considerados: palma cultivada na Colômbia e Malásia; soja na Argentina, Brasil e Estados Unidos; e colza na Alemanha, França, Espanha, Canadá e Estados Unidos. Foi desenvolvida uma abordagem para facilitar o processo de decisão que permite ao decisor escolher a mistura com base na performance ambiental global. Os resultados mostram que é possível utilizar OAU em misturas com óleos virgens sem comprometer a qualidade do biodiesel se a incerteza composicional dos óleos for tida em conta. Estas misturas apresentam menores custos relativamente a misturas de óleos virgens. A percentagem de redução depende da relação entre os preços dos diferentes óleos. Adicionalmente, o uso de OAU nas misturas permite obter também uma redução na variação dos custos de produção porque o preço desta matéria-prima apresenta menor volatilidade relativamente à observada nos óleos convencionais. As diferenças observadas na avaliação ambiental dos diferentes óleos virgens estão relacionadas com a escassez de água da região e o esquema de fertilização/pesticidas usados em cada cultura/local. Os resultados mostram que pegadas hídricas mais elevadas devem-se simultaneamente a maiores consumos de água e elevada escassez dos locais de cultivo. Para as categorias de toxicidade (HT e FT), os valores mais elevados são devido à elevada quantidade de pesticidas utilizados no cultivo, enquanto que para CC, AA e EU a maior contribuição provém da quantidade de fertilizantes. WCO apresenta os menores valores para WSI, CC, EU e AA. Na análise multiobjectivo realizada, observou-se que soluções (misturas) com valores de CC e WSI mais baixos podem ser obtidos com menor custo se OAU for incluído nas misturas. A mesma conclusão é obtida quando mais objectivos ambientais (AA, EU, FT e HT) são considerados na análise. A ferramenta de apoio à decisão desenvolvida facilita o processo de decisão ao permitir a visualização do compromisso entre o objectivo económico e os ambientais quando mais do que três objectivos são considerados. Nesta investigação é evidenciado que a inclusão de OAU num portfólio diversificado de matérias-primas usado em modelos de optimização de misturas é uma abordagem atractiva para melhorar a performance económica e ambiental do biodiesel. O modelo desenvolvido pode ser utilizado para optimizar a mistura de matérias-primas alternativas e avaliar a viabilidade técnica de utilizar outros resíduos (por ex. gorduras animais) nas misturas. Embora a ferramenta tenha sido desenvolvida especificamente para produção de biodiesel, pode ser aplicada a outras indústrias, nomeadamente de reciclagem, para apoio à decisão no planeamento de produção com vista a melhorar a performance técnica, económica e ambiental dessas indústrias. Project EMSURE (Energy and Mobility for Sustainable Regions, CENTRO 07 0224 FEDER 002004) FEDER/FCT | PTDC/AGR-FOR/1510/2014 (POCI-01-0145-FEDER-016764) - SUSTAINFOR: Sustainability assessment of forest sector management strategies in the context of a bioeconomy FEDER/FCT | PTDC/AAG-MAA/6234/2014 (POCI-01-0145-FEDER-016765) - SABIOS: Sustainability assessment of bioenergy systems: a life-cycle multi-criteria decision-support approach, including land use change

Abstract

RESUMO: O sistema de transporte coletivo da cidade de Curitiba, no Paraná, é reconhecido pelas suas soluções inovadoras e modelo para o Brasil. Neste trabalho foi analisada a influência do combustível (diesel e biodiesel) e das condições da frota de veículos do transporte coletivo de Curitiba nas emissões de NOx, e essa é uma iniciativa pioneira. Foram selecionados 188 veículos (9,7% do total) com motores de 7 a 12 L, denominados B7R, B10M, B12M e B215RH, e foram realizadas medições de NO e NO2 na saída dos escapamentos. Com relação ao tipo de combustível, as emissões de NO e NO2 para o biodiesel (B100) foram, respectivamente, 37 e 26% superiores aos valores observados com o combustível diesel (S10). Comparando motores B12M com até 3 e 10 anos de operação, as emissões médias de NOx foram próximas de 40% maior. Assim, foi possível observar que os veículos a biodiesel tiveram maior emissão de NOx quando comparados com veículos a diesel, em condições similares de operação e tempo de uso do motor. Entretanto, embora o uso de biodiesel traga vantagens ambientais, como energia renovável, novas tecnologias e dispositivos devem ser desenvolvidos para controlar emissões de NO e NO2 em motores que utilizam esse tipo de combustível. Para trabalhos futuros, os autores recomendam testes em dinamômetro, para simular emissões de NOx em motores a diesel e biodiesel em diferentes condições de carga e regime de rotação do motor. ABSTRACT: The public transportation system in Curitiba, Paraná, Brazil, is recognized by its innovative solutions; and is a model for Brazil. In this work, the influence of fuel (diesel and biodiesel) and the conditions of the public transport vehicle fleet of Curitiba in NOx emissions was assessed, and this is a pioneered initiative. A total of 188 vehicles (9.7% of the total) with engines of 7 and 12 L were selected, named B7R, B10M, B12M and B215RH, and measurements of NO and NO2 were performed in the exhaust output. In relation to the type of fuel, the emissions of NO and NO2 for biodiesel (B100) were, respectively, 37 and 26% superior to the values observed with the fuel diesel (S10). Comparing the engines B12M with up to 3 and 10 years of operation, the average emissions of NOx were close to 40% higher. Thus, it was possible to observe that the biodiesel vehicles had higher NOx emissions when compared with diesel vehicles in similar conditions of operation and engine wear time. Therefore, although the use of biodiesel brings environmental advantages, as renewable fuel, new technologies and devices must be developed to control emissions of NO and NO2 in engines that use this type of fuel. For future works the authors recommend tests on dynamometer to simulate NOx emission in diesel and biodiesel engine in different conditions of charge and engine speed. Document type: Article