Many fuel spray characterization studies to date have been conducted in quiescent environments with single-hole fuel injectors. However, in actuality, multi-hole injectors spray into direct injection engine cylinders where significant air swirling and tumbling exist to promote fuel atomization and air-fuel mixing, which result in more efficient combustion. For this reason, researchers have begun developing correlations for fuel sprays where a jet of air acts perpendicularly to the fuel spray, also known as a cross airflow or crossflow, so as to more realistically predict fuel spray characteristics in direct injection engines. Accordingly, there is a need for a foundation of experimental data reflecting the specific conditions of fuel spray in cross airflow which can then be used for model validation and future engine design and development. In this study, fuel sprays are characterized with a commercial 8-hole fuel injector in a wind tunnel enclosure capable of cross airflows upwards of 200m/s. Particle image velocimetry was used to measure air velocities and capture pulsed spray events of biodiesel, diesel, and biodiesel-diesel blend fuels. Spray images were processed and analyzed in LaVision's DaVis and in MATLAB to calculate spray penetration length and axis deflection angle under varying cross airflow velocities, fuel injection pressures, and fuel types. Results show that strong cross airflows can decrease spray penetration by up to 44% and deflect the spray axis by up to 10.5° when compared to the same spray in a quiescent environment. Additional experiments reveal that biodiesel experiences slower spray progression when compared with diesel, resulting in shorter spray penetrations in the early phase of the spray development (up to 0.7ms after the start of injection, or ASOI). The angle between the fuel injector axis and the air jet axis plays an important role in determining the resultant spray characteristics. This angle should be considered in future correlations.

Many recent studies on the relative costs and benefits of biofuels have raised the need for a detailed and rigorous analysis of the operations of a biorefinery that is focused on optimization. The current thesis concentrates on the design and optimization of plants for producing biodiesel and ethanol from cellulosic biomass. We have performed numerical simulations combined with systematic parametric analyses to investigate the effect of various parameters on the overall material and energy balances of each biorefinery. The efficiency of the simulated processes was investigated by introducing and/or estimating various metrics in order to select the more beneficial directions for process improvements. Particular emphasis has been paid on heat integration and the design of highly efficient combined heat and power (CHP) units that generate the steam and electricity needed for the purification of biofuels and their co-products. The first part of the thesis is focused on biodiesel production via transesterification of soybean oil with methanol, under alkali-catalyzed conditions. We have analyzed the performance of several reactor configurations in order to improve the conversion of the reversible transesterification reactions. The effect of the oil to alcohol ratio has also been extensively explored. Furthermore, the energy requirements of the simulated process have been rigorously calculated. Since biodiesel facilities can be used either for small-scale, distributed applications or for large-scale production, we have explored whether it is more energy efficient to burn the glycerol-rich stream in a combined heat and power (CHP) plant, or purify the glycerol and use it a feedstock for producing higher-value chemicals with further biotechnological processes. The second part of the thesis focuses on the production of cellulosic ethanol. Having developed the process model, a detailed parametric analysis was carried out to determine how the energy balances and overall efficiency of the biorefinery were influenced by changes in (a) the composition of the biomass feedstock, and (b) the conversion levels of the hydrolysis and fermentation stages. Furthermore, the requirements of the utility section of the ethanol plant were calculated. The utility section included a combined heat and power unit where by-product streams of the production process were utilized for energy generation. The parametric analysis indicated that these streams were in most cases an insufficient fuel source for meeting the energy requirements of the plant and thus, additional fuel was required (biomass, coal, or natural gas). The calculations of this section indicated a significant trade-off between ethanol production and external energy inputs, thus casting some doubt on the ultimate effectiveness of efforts to develop genetically modified energy crops (with high carbohydrate content) in order to maximize fuel production.

This essay is written within my education for Technical Officer in the Swedish armed forces. The essay describes the alternative fuels that the Swedish armed forces can make use of if the supply of fossil fuels is insecure. The alternative fuels that are described and compared are; Synthetic diesel, Organic diesel, Methanol and Ethanol. The essay describes the process of producing the alternatives, the need for modification and the economics for each alternative. The alternatives are compared and assessed for their ability to secure the supply of fuel to the Swedish Armed Forces. The result of the study is that, while synthetic diesel has the best chemical constitution but is not produced in Sweden, the best alternative fuel for the Swedish armed forces at this moment is organic diesel.

Examensarbetet har gjorts i samarbete med SP, Sveriges tekniska forskningsinstitut. De vill genom denna rapport börja få svar på frågan, om det är lönsamt att odla alger till biodieselframställning under svenska förhållanden, för att sedan möjligen påbörja en forskning inom området. Rapporten granskar till en början, via informationssökning, vad som är gjort tidigare och vilka företag och forskare som arbetar inom området idag. Därefter undersöks de steg som algerna genomgår för att bli biodiesel, det vill säga odling, skördning, utvinnande av algolja och slutligen framställningen av biodiesel ifrån algoljan. Olika alger, utrustningar och metoder studeras och ekonomiska siffror sammanställs vad gäller produktionen av alg-biodiesel. Slutligen undersöks vilket intresse området har hos olika svenska företag. Problemområden tillsammans med effektiviseringar diskuteras. Resultatet är ett flödesschema över en önskemodell för svenska förhållanden. Flödesschemat innehåller de lösningar och metoder som förväntas ha stor potential, dock så fastslås det inte att det skulle vara den enda lösningen. Höjdpunkterna i denna modell är användandet av en mixotrof alg som odlas i slutna bioreaktorer. Algerna ska få en ökad tillförsel av koldioxid ifrån till exempel kraftvärmeverk tillsammans med glycerol, vilket gynnar tillväxten med möjligen upp till tretton gånger. Glycerol är en biprodukt vid biodieselframställning vilket därmed kommer att göra det till ett billigt näringsmedium vid mixotrof växt. Även värme är en restprodukt som tillförs algerna ifrån kraftverket. Denna metod kommer samtidigt fungera som koldioxidrening och kväveoxidrening för kraftvärmeverket. Rapporten visar även på att övergött vatten, innehållande fosfor och kväve, kan renas med algerna och detta tillförs med fördel till de slutna bioreaktorerna. Skördning av algerna görs genom flotation med löst syre eller genom att störa koldioxidflödet. Både syre och koldioxid kan tillföras ifrån andra steg i flödesschemat. Oljan extraheras fördelaktligen ifrån algerna med hjälp av produkten biodiesel och oljan omvandlas därefter till mer biodiesel genom transesterifiering med hjälp av mikrovågor. Resultatet visar också att alg- biomassan kan användas till att framställa en rad olika restprodukter, där djurfoder, föda till tredje världen, bioplast och andra biobränslen är de mest intressanta. Rapporten visar på ett stort intresse ifrån olika aktörer inom bland annat flygindustrin, kärnkraftverk, oljebolag och energibolag i Sverige.

Petroleum-based fuel dominates the global energy system despite the fact that this resource is diminishing. Additionally, Small Island Developing States (SIDS) face a number of challenges to development such as resource scarcity, locational isolation, and uneven development. These challenges make it difficult for these nations to compete in the global market for fuel. Incidentally, biodiesel, made from waste cooking oil, can be used in automotive diesel engines or diesel generators for electricity. Currently, these two areas: development in SIDS and biodiesel, are separate topics in the literature and a relationship between the two has yet to be developed. This research will describe how a biodiesel-based energy system can address some of the challenges to development faced by SIDS. One such system in Barbados is used as a case study. Informal interviews and participant observation reveal the benefits and challenges of setting up and maintaining a biodiesel energy system. Also, the potential to scale-up the biodiesel energy system to the national level is assessed. An evaluation framework, derived from the literature, is used to rate the success factors of the existing biodiesel operation and as well as the steps required for scaling up. The results of this study prove the numerous and interconnecting benefits of a biodiesel-based energy system. Biodiesel produced on the island using locally-generated waste cooking oil creates a new local resource, addressing the challenge of resource scarcity, and reduces the demand for imported petroleum-based diesel. The biodiesel system addresses the issue of uneven development by connecting different communities across the island through public participation. However, funding difficulties in the biodiesel operation arose after a change of ownership. This made obtaining methanol, an ingredient in biodiesel production, problematic and ultimately halted production. Based on the findings, it is recommended that community biodiesel-based energy systems include the use of a locally-produced alcohol as a substitute for methanol. Also, operations should be scale-up through decentralization in order to keep equipment costs down and better address the challenge of uneven development faced by SIDS. With proper management and sufficient funding and community support, a biodiesel-based energy system is able to contribute to sustainable development in light of the unique situation present in SIDS.

<p>Examensarbetet har gjorts i samarbete med SP, Sveriges tekniska forskningsinstitut. De vill genom denna rapport börja få svar på frågan, om det är lönsamt att odla alger till biodieselframställning under svenska förhållanden, för att sedan möjligen påbörja en forskning inom området.</p><p>Rapporten granskar till en början, via informationssökning, vad som är gjort tidigare och vilka företag och forskare som arbetar inom området idag. Därefter undersöks de steg som algerna genomgår för att bli biodiesel, det vill säga odling, skördning, utvinnande av algolja och slutligen framställningen av biodiesel ifrån algoljan.</p><p>Olika alger, utrustningar och metoder studeras och ekonomiska siffror sammanställs vad gäller produktionen av alg-biodiesel. Slutligen undersöks vilket intresse området har hos olika svenska företag. Problemområden tillsammans med effektiviseringar diskuteras.</p><p>Resultatet är ett flödesschema över en önskemodell för svenska förhållanden. Flödesschemat innehåller de lösningar och metoder som förväntas ha stor potential, dock så fastslås det inte att det skulle vara den enda lösningen. Höjdpunkterna i denna modell är användandet av en mixotrof alg som odlas i slutna bioreaktorer. Algerna ska få en ökad tillförsel av koldioxid ifrån till exempel kraftvärmeverk tillsammans med glycerol, vilket gynnar tillväxten med möjligen upp till tretton gånger. Glycerol är en biprodukt vid biodieselframställning vilket därmed kommer att göra det till ett billigt näringsmedium vid mixotrof växt. Även värme är en restprodukt som tillförs algerna ifrån kraftverket. Denna metod kommer samtidigt fungera som koldioxidrening och kväveoxidrening för kraftvärmeverket.</p><p>Rapporten visar även på att övergött vatten, innehållande fosfor och kväve, kan renas med algerna och detta tillförs med fördel till de slutna bioreaktorerna.</p><p>Skördning av algerna görs genom flotation med löst syre eller genom att störa koldioxidflödet. Både syre och koldioxid kan tillföras ifrån andra steg i flödesschemat. Oljan extraheras fördelaktligen ifrån algerna med hjälp av produkten biodiesel och oljan omvandlas därefter till mer biodiesel genom transesterifiering med hjälp av mikrovågor.</p><p>Resultatet visar också att alg- biomassan kan användas till att framställa en rad olika restprodukter, där djurfoder, föda till tredje världen, bioplast och andra biobränslen är de mest intressanta.</p><p>Rapporten visar på ett stort intresse ifrån olika aktörer inom bland annat flygindustrin, kärnkraftverk, oljebolag och energibolag i Sverige.</p>

Hong Kong is vulnerable to energy and economic security due to the heavy dependence on imported fossil fuels. Waste has also been a major environmental management problem due to the amount of rubbish produced every year but lacking the technology and capital to manage different types properly. The objective of the dissertation is to study the feasibility of the use of biofuel in Hong Kong by recycling local waste. Current government policies in Hong Kong and overseas are being investigated on the appropriateness for domestic use. Literature reviews and stakeholders’ questionnaires are accounted to analyse the adaptability and popularity of the biodiesel application. The methodology of the dissertation is to firstly examine literature reviews regarding biodiesel’s environmental aspect, technical efficiencies, economic aspect, government incentives and tax constraints. The consensus outcome of these researches advocated high popularity of biodiesel consumption and production in Europe and U.S. due to lower environmental impact, equivalent output efficiency and strong government support. Their successful implementation is a good example to improvise biodiesel domestically in Hong Kong. Secondly, interviews were conducted with Hong Kong’s limited stakeholders. Respondents such as Hong Kong International Airport, Hong Kong Jockey Club, Fairwood Fastfood MTR Maritime Square were interviewed as these participants have been the pioneers in Hong Kong by recycling waste into biodiesel. On the production side, two out of three bio-refineries in Hong Kong provided their business sustainability and feasibility comments to pursue a long term goal. The limitation on responses might be focused solely on a few peer groups, and not the appropriate stakeholders with proper sampling size. However, the results are concurrent that biodiesel is one of the best alternative energy in Hong Kong. The dissertation draws positive results based on the following factors. Biodiesel can diminish the tremendous cost on waste management and landfill dumping. Using local food waste and industrial wastes from restaurants and food factories as feedstock to produce biodiesel is positive. This will also minimise the heavy reliance on imported fossil fuels to diversify energy sources. Refuelling of biodiesel fuel can be performed in any gas stations with the use of the existing infrastructure without any further requirement of new investment. Nonetheless, in order to facilitate the use of biodiesel, incentives programmes initiated by Hong Kong Government and the biofuel producers have to coherently promote this alternative fuel. The conclusion states that Hong Kong is completely feasible to adopt the use of biodiesel in medium to heavy sized vehicles and vessels in the commercial sector. The environmental benefit of Hong Kong using biodiesel stood out compared to other form of renewable energy. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Biodiesel is a promising renewable alternative fuel to fossil energy. For the biodiesel production from low-cost feedstock, a pretreatment step is essential, which is the esterification of free fatty acids (e.g. oleic acid) in the feedstock in order to avoid soap formation and minimize catalyst deactivation. Sulfuric acid modified zirconia (H2SO4-ZrO2) is known as an effective heterogeneous catalyst for esterification. However, due to rapid 〖SO〗_4^(2-) leaching, its reusability is low and its practical use is thus largely hindered. Zirconia supported on silica (ZrO2-SiO2) serves as a kind of non-sulfated zirconia catalyst against the leaching of the active species. Moreover, the silica support offers a large surface area and excellent thermal stability, which can accommodate a number of active zirconia species. Furthermore, there are Zr-O-Si bondings at the contact area between ZrO2 and SiO2, which might result in the formation of a new strong acid species and induce an increase of the zirconia acidity accordingly. Herein, two types of ZrO2-SiO2 catalysts were prepared, by using the reverse microemulsion method and sol-gel-hydrothermal method, denoted as ZrO2-SiO2-ME and ZrO2-SiO2-SG, respectively. The as synthesized ZrO2-SiO2 were characterized by TEM, SEM, EDX, XRD, BET and IR. ZrO2-SiO2-ME demonstrated a good dispersion of ZrO2 nanoparticles, encapsulating in the monodispersed SiO2 host matrix, while ZrO2-SiO2-SG possessed the SiO2 support with a mesoporous structure, with an average pore size of ~7 nm and a surface area of 418 m2/g. The catalysts both exhibited excellent catalytic activity and stable performance in the esterification of oleic acid. Besides non-sulfated zirconia, sulfated zirconia catalysts other than traditional H2SO4-ZrO2 were also developed as solid acid catalysts for biodiesel production. Two sulfur-containing strong acids, chlorosulfonic acid (HClSO3) and (NH4)2SO4, were employed to acidify ZrO2, and two sulfated zirconia catalysts were prepared accordingly, namely HClSO3-ZrO2 and S-ZrO2. They were characterized by SEM, EDX, XRD, BET, IR, TGA and NH3-TPD. Comparing with H2SO4-ZrO2, HClSO3-ZrO2 and S-ZrO2 contained higher sulfur content and more acid sites. More importantly, both HClSO3-ZrO2 and S-ZrO2 demonstrated high catalytic activity and excellent durability in the esterification of oleic acid. It is known that consecutive esterification and transesterification reactions are suitable for direct biodiesel production and acetylation of glycerol enables the conversion of this biodiesel byproduct to a biofuel additive. Therefore, all the above mentioned catalysts were examined to compare their catalytic abilities in these reactions. Among the four catalysts, HClSO3-ZrO2 exhibited the highest catalytic activity in both reactions under optimal conditions. The thesis work here described the preparation and characterization of four types of ZrO2-based solid acid catalysts. Their catalytic activities were thoroughly investigated upon the several essential steps in biodiesel production. In addition, the synthesis condition-activity relation was studied and the synthesis and reaction conditions were delicately tuned. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

D. Tech. Chemical Engineering / Objectives of the study is to optimize the production of biodiesel from non-edible oils using both homogeneous and heterogeneous catalysts.

The efficacy of biodiesel as a co-solvent for copper naphthenate wood preservative treating solutions was evaluated using two fungal decay methodologies (AWPA E10-09, British Standard Method EN113). Four fungal species (Gloeophyllum trabeum, Trametes versicolor, Poria xantha, Postia placenta) and three wood species (Douglas fir, Southern yellow pine, Western red cedar) with six replicates were utilized in both studies. Two levels of biodiesel: diesel (30:70 and 50:50) were compared to diesel-only solvent systems for copper naphthenate treating systems and treated to AWPA recommended retentions. No differences in decay efficacy between the biodiesel blends and diesel-only treatment in either the AWPA or the EN113 decay studies were detected for either standard method. Copper distribution was evaluated using SEM-EDX and no differences were noted with either solvent system. It was determined that the presence of biodiesel did not have a negative impact upon the efficacy of copper naphthenate as a wood preservative.