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Kohli, DhruvDevelopment and Validation of a NOx Emission Testing Setup for a Diesel Engine, Fueled with Bio-Diesel
Master of Science (MS), Ohio University, 2009, Mechanical Engineering (Engineering and Technology)
The increasing concerns related to long term availability of petroleum-based fuels and the emissions from diesel-powered vehicles have given rise to a growing search for an alternate source of fuels for use in diesel vehicles. One of the most recent and promising findings in this field is “Bio-diesel”. The thesis uses a comparative study of NOx emission characteristics for regular diesel fuel and soy based biodiesel for a four cylinder, 60 HP turbocharged diesel engine for validation of the engine and the emission test rig. Modifications are recommended for the current test setup and test procedure to enable research quality testing of Algae based biodiesel.

Committee:

Gregory G Kremer (Advisor); David Bayless (Committee Member); Ben Stuart (Committee Member); Helmut Paschold (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

NOx Emission Testing; NOx Emission Testing Setup; Biodiesel comparison to diesel; NOx testing for Biodiesel

Tzillah, AishaThe Emissions of Criteria Air Pollutants from Biodiesel Fuel Usage
MS, University of Cincinnati, 2009, Engineering : Environmental Engineering
Diesel-powered compression ignited engines contribute large amounts of sub-micron particulate matter to the environment and have been shown to contribute to atmospheric greenhouse gases and deleterious health effects. Biodiesel is a proposed alternative biofuel produced through transesterification, a process in which organically derived oils combine with a methyl or ethyl alcohol in the presence of a catalyst, typically potassium or sodium hydroxide, to form ethyl or methyl ester. This biomass derived ethyl or methyl ester is non-toxic, less odorous, biodegradable, renewable, and safer to handle than petroleum diesel. Biodiesel can mix with conventional petroleum diesel fuel or used as a neat fuel in compression ignited engines. The main objectives of the research are to compare selected emissions of petroleum diesel fuel with biodiesel fuel and fuel blends, soybean as the source oil, under different engine conditions in order to determine its impact on air quality. A non-road diesel engine generator allowed for the characterization of the emissions from operating on petroleum diesel fuel, B50, and B100. The particulate matter and gaseous emissions were collected with a high-volume single dilution sampler and the exhaust stream was evaluated with a gas analyzer. The filters utilized for particulate matter collection and the adsorbents employed for gaseous pollutant collection were extracted for organic analysis with GC/MS instrument. The organic composition of the fuels and the emitted particulate matter and gaseous pollutantswere compared at various engine loads. The use of biodiesel in compression ignition engines has shown to be a viable alternative to petroleum diesel. Biodiesel is an environmentally sustainable fuel that does not contain sulfur or aromatics and may decrease the overall detrimental effects of diesel-powered engines.

Committee:

Mingming Lu, PhD (Committee Chair); Edwin Corporan (Committee Member); Sumana Keener, PhD (Committee Member)

Subjects:

Environmental Engineering

Keywords:

Biodiesel;Diesel;Biodiesel emissions;Diesel emissions

Liu, YangMaking biodiesel from spent coffee grounds through in situ transesterification
MS, University of Cincinnati, 2015, Engineering and Applied Science: Environmental Engineering
Biodiesel industry, as one of the commercially established renewable energy industries, is booming in recent years. Biodiesel helps reduce the emission of carbon monoxide, hydrocarbons and total particular matters as compared with petroleum diesel. The potential of producing biodiesel from the spent coffee grounds (SCGs) via in situ method was studied in this project. In the U.S., the average coffee consumption was 24.2 gallons per person in 2008. According to the USDA, the world’s coffee production in 2011/2012 was 8.64 million tons. Since SCGs were disposed as waste nowadays, include SCGs as biodiesel feedstock will come at a negligible cost for the biodiesel producers. The primary goal of this study was to investigate the feasibility of the in situ process to make biodiesel from SCGs without the solvent extraction step. The effects of reaction time, reaction temperature, types of catalyst, and the concentrations of the catalyst on the quantity and quality of the final coffee biodiesel were studied. In order to compare with the in situ method, the conventional biodiesel production method was also studied. Characteristics included density, FAME (Fatty Acids Methyl Ester) profile, and yield were measured. GC-MS and QTA were used to determine the composition of the coffee biodiesel and the coffee biodiesel conversion efficiency. C16:0 and C18:2 were two main FAME components within the coffee biodiesel. Moreover, SCGs residue after biodiesel production was proposed to be made into coffee activated carbon. Thermogravimetric analyzer was used to study the mass change profile of the grounds before and after coffee oil extraction. Sieving test was applied to understand the size distribution difference of the SCGs before and after oil removal. The surface area of the coffee activated carbon was measured by BET test. The outcome indicated that the oil extracted via the soxhlet extraction could reach an average value of 15.84 ± 0.30 wt. % when using a solvent mixture of hexane/isopropyl alcohol (1:1 vol.) with the extraction condition at 70 °C and 7 hours. The coffee activated carbon could have a surface area up to 1,174 m2/g which had potential to be utilized as a purification material to purify the biodiesel. The highest in situ coffee biodiesel yield was 17.08 wt. % under the conditions of 20 wt. % H2SO4 impregnated SCGs with 70 °C and 17 hours. However, in consideration of the energy consumption and the economic cost, 20 wt. % H2SO4 impregnated SCGs reacted at 70 °C and 7 hours was regarded as the optimum reaction condition (coffee biodiesel yield was 16.32 wt. %). As compared to the two-step method, in situ method facilitated the coffee oil extraction.

Committee:

Mingming Lu, Ph.D. (Committee Chair); Timothy Keener, Ph.D. (Committee Member); George Sorial, Ph.D. (Committee Member)

Subjects:

Environmental Engineering

Keywords:

Biodiesel;Spent Coffee Grounds;Activated Carbon;in situ

Kadiyala, AkhilDevelopment and Evaluation of an Integrated Approach to Study In-Bus Exposure Using Data Mining and Artificial Intelligence Methods
Doctor of Philosophy in Engineering, University of Toledo, 2012, Civil Engineering

The objective of this research was to develop and evaluate an integrated approach to model the occupant exposure to in-bus contaminants using the advanced methods of data mining and artificial intelligence. The research objective was accomplished by executing the following steps. Firstly, an experimental field program was implemented to develop a comprehensive one-year database of the hourly averaged in-bus air contaminants (carbon dioxide (CO2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), 0.3-0.4 micrometer (¿¿¿¿m) sized particle numbers, 0.4-0.5 ¿¿¿¿m sized particle numbers, particulate matter (PM) concentrations less than 1.0 ¿¿¿¿m (PM1.0), PM concentrations less than 2.5 ¿¿¿¿m (PM2.5), and PM concentrations less than 10.0 ¿¿¿¿m (PM10.0)) and the independent variables (meteorological variables, time-related variables, indoor sources, on-road variables, ventilation settings, and ambient concentrations) that can affect indoor air quality (IAQ). Secondly, a novel approach to characterize in-bus air quality was developed with data mining techniques that incorporated the use of regression trees and the analysis of variance. Thirdly, a new approach to modeling in-bus air quality was established with the development of hybrid genetic algorithm based neural networks (or evolutionary neural networks) with input variables optimized from using the data mining techniques, referred to as the GART approach. Next, the prediction results from the GART approach were evaluated using a comprehensive set of newly developed IAQ operational performance measures. Finally, the occupant exposure to in-bus contaminants was determined by computing the time weighted average (TWA) and comparing them with the recommended IAQ guidelines.

In-bus PM concentrations and sub-micron particle numbers were predominantly influenced by the month/season of the year. In-bus SO2 concentrations were mainly affected by indoor relative humidity (RH) and the month of the year. NO concentrations inside the bus cabin were largely influenced by the indoor RH, while NO2 concentrations primarily varied with the month of the year. Passenger ridership and the month of the year mainly affected the in-bus CO2 concentrations; while the month and sky conditions had a significant impact on CO concentrations within the bus compartment.

The hybrid GART models captured majority of the variance in in-bus contaminant concentrations and performed much better than the traditional artificial neural networks methods of back propagation and radial basis function networks.

Exposure results indicated the average 8-hr. exposure of biodiesel bus occupants to CO2, CO, NO, SO2, and PM2.5 to be 559.67 ppm (¿¿¿¿ 45.01), 18.33 ppm (¿¿¿¿ 9.23), 5.23 ppm (¿¿¿¿ 4.49), 0.13 ppm (¿¿¿¿ 0.01), and 13.75 ¿¿¿¿g/m3 (¿¿¿¿ 4.24), respectively. The statistical significance of the difference in exposure levels to in-bus contaminants were compared during morning, afternoon, and evening/night time periods. There was statistically significant difference only between the morning (driver 1) and the evening/night (driver 3) exposure levels for CO2 and PM2.5. CO levels exceeded the TWA in some months.

Committee:

Dr. Ashok Kumar, PhD (Committee Chair); Dr. Devinder Kaur, PhD (Committee Member); Dr. Cyndee Gruden, PhD (Committee Member); Dr. Defne Apul, PhD (Committee Member); Dr. Farhang Akbar, PhD (Committee Member)

Subjects:

Civil Engineering; Environmental Engineering; Environmental Health

Keywords:

Indoor Air Quality; Public Transportation Buses; Biodiesel; Data Mining; Sensitivity of the Regression Trees; Artificial Neural Networks; Genetic Algorithm Neural Networks; Evolutionary Neural Networks; In-Bus Exposure; Air Quality Model Validation

Wallace, Scott J.Diesel Engine Energy Balance Study Operating on Diesel and Biodiesel Fuels
Master of Science (MS), Ohio University, 2008, Mechanical Engineering (Engineering and Technology)
The use of alternative fuels addresses the issues of: reducing dependence on unstable petroleum supplies, reducing harmful emissions, and using renewable energy sources. This thesis focuses on a comparative energy balance on a four cylinder turbocharged diesel engine operating on diesel and biodiesel fuels. Steady-state tests were run to experimentally determine how input energy in the form of fuel was appropriated throughout the engine. The transfer of energy was measured for losses to the engine coolant and exhaust, usable power output, as well as minor and unaccounted losses. The results showed that input energy from biodiesel was distributed 37.4%, 31.1%, and 29.6% to the major areas of coolant, exhaust, and power output, respectively. Similarly the input energy from diesel was distributed 37.5%, 31.4%, and 29.2% to the major areas of coolant, exhaust, and power output, respectively. It was concluded from an uncertainty analysis that there was not a statistically significant difference in these results. Future improvements to obtain distinguishable results are outlined.

Committee:

Gregory G. Kremer (Committee Chair)

Subjects:

Energy; Mechanical Engineering

Keywords:

energy balance; energy appropriation; engine energy balance study; heat loss analysis; diesel engine; biodiesel energy balance; thermal balance; heat transfer; heat loss

Vinay Kumar, Nerella V.An Analysis on Vehicular Exhaust Emissions from Transit Buses Running on Biodiesel Blends
Master of Science in Civil Engineering, University of Toledo, 2010, Civil Engineering
This experimental study presents a comprehensive analysis of exhaust emission variation from the public transit buses in the city of Toledo running on alternative fuels. The pollutants from the exhaust that are monitored in this study are carbon monoxide, sulfur dioxide, oxides of nitrogen (NO, NO2, and NOX), and carbon dioxide. The performance of engine variables are also measured simultaneously with exhaust emission data. The engine variables affecting the pollutant levels in the exhaust are acceleration, engine load, engine speed, vehicle speed, fuel flow rate, coolant temperature, output torque, and boost pressure.The on-road and idle-engine variation of pollutant levels in the exhaust are studied. The pollutant level variation in the exhaust of a bus is different for different operation modes. The pollutant levels are found to decrease when the vehicle is on-road, with the increase in biodiesel concentration in the base fuel. On contrast, the pollutant levels are observed to increase with biodiesel concentration, when the bus is in idle-engine mode. Furthermore, when the bus is in motion, the pollutant levels in the exhaust are less as compared to the idle-engine mode. This observation helps to understand that vehicles in motion deliver the appropriate amount of fuel into the cylinder for a more complete combustion. Also, an engine in idle mode does not run at its optimum temperature and conditions that lead to incomplete combustion. The engine initial temperature, accessory load on the engine, and engine speed are found to affect the emission levels significantly. The engines at low temperatures are found to emit pollutants of higher levels because of the initial warm-up phase of an engine. Furthermore, with the increase in load and speed, the engine has to produce higher work requiring a higher fueling rate and thereby resulting in higher emission levels in the exhaust. During the engine start, transient emissions of the monitored pollutants are significantly higher because the air-fuel ratio cannot be maintained at stoichiometric mixture during start and stop operations. Furthermore, during the engine start-up, the heat necessary in the reaction chamber is not maintained that results in incomplete combustion. Hence, more transient emissions are emitted during the engine start-up. The parameters influencing pollutant levels for on-road and idle-engine conditions are identified, using regression analysis, for different biodiesel blends. Using regression analysis, the correlation and the amount of impact associated with the engine variables on pollutant levels are identified. The regression analysis helped to identify the parameters affecting pollutant levels and the relationships between different monitored parameters and pollutants in the exhaust. This study and analysis of exhaust emission variation of biodiesel blends will assist the operators of biodiesel fleets and regulators of air pollution in selecting the appropriate operating variables for emission control strategies in their area.

Committee:

Ashok Kumar (Committee Chair); Brian Randolph (Committee Member); Dong-Shik Kim (Committee Member)

Subjects:

Civil Engineering; Environmental Engineering; Gases; Health Education; Public Health; Transportation

Keywords:

Biodiesel blends; Exhaust Emissions; on road exhaust emissions; Idle engine exhaust emissions; engine load; ultra low sulfur diesel; Alternative fuels; Urban Transit Buses; TARTA; Pollutant Emission Modeling; Engine Operating Modes; engine temperature

Chai, MingThermal Decomposition of Methyl Esters in Biodiesel Fuel: Kinetics, Mechanisms and Products
PhD, University of Cincinnati, 2012, Engineering and Applied Science: Environmental Engineering

Biodiesel continues to enjoy increasing popularity. However, recent studies on carbonyl compounds emissions from biodiesel fuel are inconclusive. Emissions of carbonyl compounds from petroleum diesel fuels were compared to emissions from pure biodiesel fuels and petroleum-biodiesel blends used in a non-road diesel generator. The concentration of total carbonyl compounds was the highest when the engine was idling. The carbonyl emissions, as well as ozone formation potential, from biodiesel fuel blends were higher than those emitted from petroleum diesel fuel. The sulfur content of diesel fuel and the source of biodiesel fuel were not found to have a significant impact on emissions of carbonyl compounds.

Mechanism parameters of the thermal decomposition of biodiesel-range methyl esters were obtained from the results of thermal gravimetric analysis (TGA). The overall reaction orders are between 0.49 and 0.71 and the energies of activation are between 59.9 and 101.3 kJ/mole. Methyl esters in air have lower activation energies than those in nitrogen. Methyl linoleate has the lowest activation energy, followed by methyl oleate, and methyl stearate.

The pyrolysis and oxidation of the three methyl esters were investigated using a semi-isothermal tubular flow reactor. The profiles of major products versus reaction temperature are presented. In the pyrolysis of methyl stearate, the primary reaction pathway is the decarboxylic reaction at the methyl ester functional group. Methyl oleate’s products indicate more reactions on its carbon-carbon double bond. Methyl linoleate shows highest reactivity among the three methyl esters, and 87 products were detected. The oxidation of three methyl esters resulted in more products in all compound classes, and 55, 114, and 127 products were detected, respectively. The oxidation of methyl esters includes decarboxylation on ester group. The methyl ester’s carbon chain could be oxidized as a hydrocarbon compound and form oxidized esters and unsaturated esters, which have been observed in methyl ester’s oxidation products. The oxidation of methyl stearate, methyl oleate and methyl linoleate produces 16, 28 and 34 types of carbonyl compounds, respectively. The unsaturated methyl ester forms more carbonyl compounds compared to the saturated methyl ester, which indicates the formation of carbonyl compounds might be more related to the unsaturated carbon bond rather than the methyl ester group.

Good agreement between results for total carbon (TC) generally has been found, but the organic and elemental carbon (OC and EC) fractions determined by different methods often disagree. Lack of reference materials has impeded progress on method standardization and understanding method biases. As part of this dissertation, uniform carbon distribution for the filter sets is prepared by using a simply aerosol generation and collection method. The relative standard deviations for the mean TC, OC, and EC results reported by the seven laboratories were below 10%, 11% and 12% (respectively). The method of filter generation is generally applicable and reproducible. Depending on the application, different filter loadings and types of OC materials can be employed. Matched filter sets prepared by this approach can be used for determining the accuracy of various OC-EC methods and thereby contribute to method standardization.

Committee:

Mingming Lu, PhD (Committee Chair); Eileen Birch, PhD (Committee Member); San-Mou Jeng, PhD (Committee Member); Timothy Keener, PhD (Committee Member)

Subjects:

Environmental Engineering

Keywords:

biodiesel;thermal decomposition;carbonyl compounds;OC-EC;TGA;;

Wyss, Sarah ChristineDesign of a Cross-Domain Quorum Sensing Pathway for Algae Biofuel Applications
Bachelor of Science (BS), Ohio University, 2013, Biological Sciences
Algal biofuels represent a promising possibility for renewable energy. Biodiesel is a particularly attractive option because it is compatible with existing engines. To produce biodiesel, algae are grown to high density with the addition of nutrients (particularly bioavailable nitrogen). When the mature algal culture is deprived of bioavailable nitrogen, a stress response is triggered which increases lipid yield. Lipids from harvested algae are chemically converted into biodiesel. However, this system is not yet economically competitive due to the high costs associated with large-scale algal cultivation, particularly the cost of nitrogen fertilizer. An alternate system is proposed in which genetically modified symbiotic bacteria provide bioavailable nitrogen to the alga based on growth phase, obviating the application of nitrogen fertilizer and removing the associated cost. In this system, the nitrogen fixation (nif) enzymes are constitutively expressed in a bacterial symbiont and convert atmospheric nitrogen into bioavailable nitrogen, which is made available to the alga. Using a quorum-sensing-like mechanism, the bacteria sense algal culture density and repress nif gene expression at high algal culture density to deprive the algae of bioavailable nitrogen. A genetic design for this sensor/switch system is discussed. Experimental progress toward the creation of this system using Chlorella vulgaris and Escherichia coli is presented. Impediments to successful experimental execution are analyzed and potential future directions are suggested.

Committee:

Soichi Tanda, Dr. (Advisor)

Subjects:

Cellular Biology; Genetics; Molecular Biology

Keywords:

Synthetic biology; paratransgenesis; algae biofuel; biodiesel; genetic modification; quorum sensing

Venkatagiri, AvinashMaterials and Methods for Algae Preconcentration
Master of Science (MS), Ohio University, 2014, Mechanical Engineering (Engineering and Technology)
The performance of two fabrics for preconcentrating algae using a low-cost methodology was measured. The porosity of the fabrics used was determined optically using Keyence Imaging Microscope and ImageJ software. The performance of the fabrics was tested in three separate conditions. The first set of experiments was gravity fed and 2 gal of algae solution was used for each test. The second set of experiments used application of vibration and gravity fed with 2 gallons of algae solution. The third set of experiments employed a diaphragm pump to vary the feed velocity of the algae solution supplied to the setup. The use of vibration and increased feed velocity showed varying results with advancements in some cases. Polyester fabric did not show increase in permeation despite cake disruption through vibration application. This was further investigated using ImageJ software and increased pore-blockage was the reason for lack of performance. Felt showed increased permeation due to vibration application. The application of increased feed velocity showed greater variability in polyester among replicate trials with increased biomass loss through the filter fabric. Felt fabric showed repeatable behavior but there was increased biomass loss through the fabric due to the increased feed velocities.

Committee:

David Bayless (Advisor)

Subjects:

Energy; Engineering; Mechanical Engineering

Keywords:

Algae Biofuel; Biodiesel; Filtration; Fabric Filtration;

Penumalla Venkata, Pavan KumarLaboratory Experiments on the Emissions from Different Biodiesel Blends in Comparison to B20 and Ultra Low Sulfur Diesel
Master of Science in Civil Engineering, University of Toledo, 2011, Civil Engineering
Biodiesel has been a promising clean alternative fuel to fossil fuels, which reduces the emissions that are released by fossil fuels and possibly reduces the energy crisis caused by the exhaustion of petroleum resources in the near future. Biodiesel is replacing diesel as an alternative fuel for internal combustion engines. Previous research studies have shown that biodiesel greatly reduces carbon monoxide (CO), hydrocarbon (HC) and particulate matter (PM) emissions compared to diesel fuels. At present, B20 (20% biodiesel in the total fuel mix) is being used commonly due to its material compatibility to changing weather conditions, emission benefits and costs. In this study biodiesel blends B5, B10 and B50 were combusted to investigate how the engine conditions influence the emission concentrations of H2, CO, CH4, CO2, N2 and morphological data of particulate matter. Different emission samples were collected for a certain range of temperatures and pressures. The samples were analyzed using Gas Chromatography and the particulate matter was analyzed using Scanning Electron Microscope images. The samples of different biodiesel blends were then compared with the emissions from B20 and Ultra Low Sulfur Diesel at the same temperature and pressure ranges. From the results under varied tested conditions it has been inferred that, for low H2 emissions, B5 combustion under low temperatures and high pressures is preferred. For low CO emissions, B20 combustion under high temperatures and pressures is preferred. For low N2 emissions, B5 combustion under low temperatures and high pressures is preferred. For low CH4 emissions, B5 combustion under low temperatures and high pressures is preferred. For low CO2 emissions, ULSD combustion under low temperatures and low pressures is preferred. H2 emissions have decreased as the biodiesel blend increased. CO was observed to increase with the blend. The emissions were comparatively lower under low temperatures. N2 showed an increasing trend with the blend. Low temperatures and high pressure reduced the emissions. Not much variation was observed for CH4 for the blends under the tested conditions. The CO2 emission from the results was observed to be on an increasing trend except for B20. Under higher pressures and temperatures CO2 emissions were lower for all the blends except for B20. ULSD showed lower emissions under low temperatures and varying pressures compared to biodiesel. B5 showed lower emissions under lower temperatures and higher pressures. B10 showed the least emissions under lower temperatures and lower pressures. B20 showed lower emissions under high pressures and varying temperatures. B50 showed the least emissions under lower temperatures and higher pressures except for CO2 which showed lower emissions under higher temperatures and pressures.

Committee:

Dr. Ashok Kumar, PhD, P.E (Committee Chair); Dr. Dong-Shik Kim, PhD, P.E (Committee Member); Dr. Brian W. Randolph, PhD, P.E (Committee Member)

Subjects:

Civil Engineering; Environmental Engineering

Keywords:

Biodiesel; emission gases; ULSD; Particulate matter

Wang, JingjingFeasibility Study for a Community Scale Conversion of Trap Grease to Biodiesel
MS, University of Cincinnati, 2012, Engineering and Applied Science: Environmental Science

The world is experiencing fossil fuel depletion, global warming and environmental deterioration due to the overuse of fossil fuels. Biodiesel, as an alternative fuel, is considered as part of the solution. Biodiesel has experienced rapid development and commercialization in the past decade, and the technology for biodiesel production has greatly improved in handling multiple feedstocks. But the development of the biodiesel industry is still facing challenges. The major obstacle to the wide use of biodiesel is that biodiesel is not cost-competitive compared with diesel fuels. The industry is constantly searching for low-cost, or even no-cost feedstocks. Therefore, trap grease can potentially serve as a promising biodiesel feedstock to boost the biodiesel industry.

Trap grease is a mixture of oils, food debris and kitchen wastes. It is generated in grease traps in restaurants. In most municipalities in the US, trap grease, after being pumped out from grease traps by grease haulers, is either sent to wastewater treatment plant or directly to landfills. An intensive literature review has been conducted and the following facts have been obtained. In the US, grease is the number one cause of clogging of public sewers, which results in costly sanitary overflow or combined sewer overflows. Various utilization ways of trap grease include composting, land application, anaerobic co-digestion, making biodiesel, combustion, incineration and rendering, etc. If trap grease is utilized as a feedstock for biodiesel production, it is not only beneficial to the biodiesel industry, but also helps solve the trap grease disposal issue. However, the challenge lies in the extraction of the oil fractions from this highly heterogeneous low grade feedstock.

The goal of this study is to evaluate the feasibility of a community scale conversion of trap grease to biodiesel. Trap grease sample used for this study was obtained from the Metropolitan Sewer District of Greater Cincinnati (designated as MSD-TG). The MSD-TG mainly consists of water (58.94%), free fatty acids (FFAs) (20.69%) and unextractable part/solids (18.17%), with the lipid part of the MSD-TG being almost all FFAs.

This study uses waste cooking oil (WCO) to extract the oil faction from the MSD-TG. WCO is also a low-cost biodiesel feedstock oil and using WCO as the solvent removes the solvent recovery step in the pretreatment process. The optimum extraction conditions were studied. It was found that 60° is the optimum extraction temperature. And at 60°, the optimum extraction duration is 90 minutes and the optimum extraction ratio is 4:1 (for every 10g of the MSD-TG 40mL (36g) of WCO is used). The extraction performance of WCO was evaluated by comparing it with three other organic solvents, methanol, hexane and isopropyl alcohol/hexane (2:1, v/v). WCO shows comparable performance among the four solvents. Based on the survey from trap grease haulers, the quantity of the grease trap waste (as semi solids) generated in Cincinnati is estimated to vary from 1.48 to 3.97 million pounds annually.

Committee:

Mingming Lu, PhD (Committee Chair); Ting Lu, PhD (Committee Member); Sumana Udom Keener, PhD (Committee Member)

Subjects:

Environmental Studies

Keywords:

trap grease;biodiesel;extraction;inventory of trap grease;;;

Lingaraju, Bala P.Removal of Nitrogen from Wastewater Using Microalgae
MS, University of Cincinnati, 2011, Engineering and Applied Science: Chemical Engineering
Presence of residual nitrogen and phosphorus in treated wastewater that is discharged into the rivers and lakes poses a problem to aquatic species by causing “eutrophication”. There is a strong necessity to bring down the levels of nitrogen and phosphorus to as low as 1 ppm so that the nutrient supply to the wild type algae growing uncontrollably can be restricted. In this study, Chlorella vulgaris was used to effectively treat wastewater from Mill Creek domestic wastewater treatment plant in Cincinnati, Ohio. Ammonia-nitrogen was the major source of nitrogen. Typically, 8-10 mg/L of ammonia-nitrogen was present in the secondary wastewater effluent. The secondary wastewater effluent was used as a medium to grow Chlorella vulgaris. Ammonia-nitrogen reduced by 99% after the batch culture. Effective results were also obtained for orthophosphate removal. The residence time of algae in wastewater required to achieve effective reduction of nutrients was reduced through culture in nitrogen deficient medium. A comparison of suspended and settled algae for their effectiveness in nutrient removal was carried out. Results indicated that suspended algae are better than settled algae. Increasing the cell density also quickens the nutrient removal process. Lipids were extracted through the well established Bligh and Dyer method and estimated gravimetrically. Additional confirmation of lipids was carried out using Transmission Electron Microscopy (TEM). The motivation behind lipid identification and estimation was to effectively utilize algae that were used to clean wastewater to produce biodiesel at a later stage. Results indicate that lipids can be extracted from Chlorella vulgaris. The Current setup is a suitable starting point for wastewater treatment and biodiesel production. However, for practical implementation, further improvements should be made in the maximum density of algae that can be achieved. Increasing the density of algae in the culture medium through elimination of growth limitations can improve the overall efficiency of removal of nitrogen from wastewater and yield of biomass, thereby increasing the yield of lipids. Improvement in the yield of lipids increases the biodiesel yield. Finally, the overall objective of wastewater treatment and renewable energy production can be achieved through improvement in maximum density of algae, for which further research is required.

Committee:

Joo Youp Lee, PhD (Committee Chair); Timothy Keener, PhD (Committee Member); Soon Jai Khang, PhD (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Chlorella vulgaris;Nitrogen Removal;Lipid Extraction;Algae Biodiesel

Burke, Thomas A.Modification and Validation of a Novel Solid-Liquid Separation Technique Using a Microscreen and Capillary Belt System
Master of Science (MS), Ohio University, 2012, Mechanical Engineering (Engineering and Technology)
One of the major contributors to high processing costs of microalgae for biofuel is the harvesting and dewatering of the microalgae, which can account for 20-30% of the total cost. Microalgae can potentially become a more economical feedstock for biofuel if the capital and operational costs of the harvesting/dewatering step are reduced by using a novel microscreen and capillary belt system. By modifying the well section of the Algaeventure Systems prototype harvester, the flow rate of live Scenedesmus dimorphus algae through the harvester system was increased by an average of 166.8% and the power consumption per unit mass was decreased by an average of 51.4%. A modified testing rig was also constructed to eliminate a belt tracking and media spill-over issue through development of an autonomous belt tracking system. Chlorella powder and tomato juice were tested under the same conditions as the live algae to determine a suitable surrogate material to live algae.

Committee:

Ben Stuart, PhD (Advisor); Gregory Kremer, PhD (Committee Member); David Bayless, PhD (Committee Member); Morgan Vis-Chiasson, PhD (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Microalgae; Harvesting; Dewatering; microscreen; capillary belt; Algaeventure Systems; AVS; biofuel; biodiesel; Scenedesmus dimorphus; algae; microalgae processing

Lau, Jia LiAn Investigation into the Derived Demand for Land in Palm Oil Production
Master of Science, The Ohio State University, 2009, Agricultural, Environmental Development Economics
Over the years, the world industry of oil palm has been rapidly increasing in the tropical areas of Asia, Africa and America. One of the major reasons behind this increase is the wider use of palm oil biodiesel as an alternative energy source. The demand for palm oil is further strengthened as more countries establish mandates on use of biofuels. The high prices for palm oil, driven partly by the introduction of palm oil biodiesel, spur even more investment in the palm oil sector. The expansion of oil palm plantation changes land use pattern. The rapid growth in the plantation area of oil palm poses several environmental challenges. The research problems of interest here are how do changes in palm oil demand determinants affect land use pattern, and to what extend the use of palm oil biodiesel contributes to demand for land in oil palm production. Dataset used in this study are from the six major producers in the world, namely Colombia, Côte d'Ivoire, Indonesia, Malaysia, Nigeria, and Thailand. The least square dummy variable derived demand model in this study takes into account the price of palm oil, economic growth, price of other vegetable oils, crude oil price, export quantity and several fixed effects variables. Own price and price of other vegetable oils do not significantly affect demand for oil palm area harvested, whereas economic growth, export market and crude oil price have significant impact on the derived demand for oil palm area harvested. The pattern of oil palm area harvested differs between countries from South East Asia and the other remaining countries. Governmental intervention and political stability have a role behind the distinctive feature of oil palm plantation across the six countries.

Committee:

BRENT SOHNGEN, PhD (Advisor); ABDOUL SAM, PhD (Committee Member)

Subjects:

Agricultural Economics; Economics; Energy; Environmental Science

Keywords:

palm oil; land; derived demand; palm oil biofuel; palm oil biodiesel; oil palm; Colombia; C&244;te d'Ivoire; Indonesia; Malaysia; Nigeria; Thailand; crude oil

Gauthier, Steven JamesBiodiesel and Crude Oil Effects on Foraging Capacity of Crayfish, Orconectus Rusticus
Master of Science (MS), Bowling Green State University, 2012, Biological Sciences
Previous research suggests that environmental pollutions such as crude oil and other petroleum based fuels inhibit and limit the perception of a chemical stimulus among other toxic effects. Alternative fuels have become more prominent today because of these environmental concerns. Due to the increase in the use of alternative fuels behavioral test are needed to determine whether alternative fuels will affect the ability of organisms to perceive chemical stimuli. To determine the impact of biodiesel on organisms chemically mediated behavior, we acutely exposed crayfish to two different fuel types (biodiesel or crude oil) at two different concentrations. Crayfish were then tested on their ability to appropriately respond to a chemical stimulus within a y-maze choice paradigm. Behavior was quantified by measuring the ability of crayfish to find the odor source, the time spent finding an odor source, and other behavioral measures associated with a y-maze choice paradigm. Results indicated that both biodiesel and crude oil impact the ability of a crayfish to perform within this bioassay. However, there were no significant differences between behavioral performances when crayfish were exposed to either fuel source. Thus, biodiesel and crude oil have equal negative effects on chemosensory behavior of crayfish. These findings have shown that biodiesel has the potential to have similar negative ecological impacts as other fuel source toxins.

Committee:

Paul Moore, PhD (Advisor); Jeffrey Miner, PhD (Committee Member); Karen Root, PhD (Committee Member)

Subjects:

Biology

Keywords:

Biology; Crayfish; Crude Oil; Biodiesel; Behavior; Foraging

Traviss, Nora M.Integration of Analysis and Deliberation to Evaluate Biodiesel Occupational and Environmental Exposures
Ph.D., Antioch University, 2008, Antioch New England: Environmental Studies

Many U.S. organizations interested in a renewable and domestic source of energy are considering switching from petroleum diesel to biodiesel blends for transportation and heavy-duty equipment use. Biodiesel is a fuel made from vegetable oils or waste grease. While there is a considerable body of evidence on the negative health effects of petroleum diesel exhaust exposures in occupational and urban settings, there has been little research examining the impact of biodiesel fuel on occupational and environmental exposures. This dissertation combined a collaborative exposure assessment of B20 (20% soy-based biodiesel/80% diesel) at a rural recycling center with a policy intervention to deliberate the results of this analysis and potential policy outcomes. I applied the National Research Council's (1996) analytic-deliberative model to connect the collaborative exposure assessment with a Biodiesel Working Group, which catalyzed policy decisions about the manufacture and use of biodiesel in Keene, NH.

Researchers and undergraduate students from Keene State College and employees from the City of Keene Department of Public Works quantitatively estimated diesel and biodiesel exposure profiles for particulate matter (< 2.5 microns diameter), elemental carbon, organic carbon, and nitrogen dioxide using standard occupational and environmental air monitoring methods. I collected qualitative data to examine the genesis, evolution and outcomes of the Biodiesel Working Group. Integrating analysis and deliberation led to a number of positive outcomes related to local use of B20 in nonroad engines. Particulate matter and elemental carbon concentrations were significantly reduced (60% and 22% respectively) during B20 use at the field site. Organic carbon levels were significantly higher (370%) during B20 use. Although NO2 levels were 19% higher, this increase was not statistically significant. Connecting the analysis with deliberation improved the quality of the exposure assessment, increased dissemination of the research results in the local community, and catalyzed novel policy outcomes, including the development of a unique public/private partnership to manufacture biodiesel locally from waste grease.

Committee:

Thomas Webler, PhD (Committee Chair); Rachel Thiet, PhD (Committee Member); Melinda Treadwell, PhD (Committee Member)

Subjects:

Environmental Science; Occupational Safety

Keywords:

biodiesel; diesel exhaust; exposure assessment; particulate matter; elemental carbon; risk analysis; collaborative research; community based participatory research; deliberation; health effects

Hermanson, Doug MatthewThe Impact of Biofuel Production on Energy and Agricultural Price Relationships
Master of Science, The Ohio State University, 2008, Agricultural, Environmental Development Economics
The production of biofuels has increased significantly within the United States from 2005 to 2008. Soybean oil and corn have been the two major feedstocks in the production of biodiesel and ethanol in the United States. The use of soybean oil in the production of biodiesel and corn in the production of ethanol potentially transforms two independent relationships between both corn and gasoline and soybean oil and diesel into a substitute or complementary relationship. Through cointegration testing and the calculation of a confidence interval of correlation coefficients the hypothesis was tested that price relationships between corn and gasoline and also soybean oil and diesel have changed due to increased production of biofuels. The results of the cointegration tests were inconclusive in testing the hypothesis due to stationarity in several of the price series. The calculation of a bootstrap confidence interval of correlation coefficients from 1980 to 2008 showed that correlation between soybean oil and diesel prices and corn and gasoline prices from 2005 to 2008 was greater than the mean correlation over the entire 28 year period. The results provide evidence that increased biofuel production has led to a new economic relationship between agricultural and energy commodities. As a result food, agriculture and livestock industries are subject to a new type of price risk that is influenced by energy markets, not just agriculture markets.

Committee:

Matthew Roberts, C (Advisor); Stanley Thompson, R (Committee Member)

Subjects:

Economics

Keywords:

biofuel; ethanol; biodiesel; cointegration; correlation

Maddi, BalakrishnaPyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass
Doctor of Philosophy, University of Toledo, 2014, Chemical Engineering
Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from protein degradation). Algal bio-char also had a significantly higher N-content. Overall, our results suggest that it is feasible to convert algal cultures deficient in lipids, such as nuisance algae obtained from natural blooms, into liquid fuels by thermochemical methods. Next, pyrolysis characteristics of each of the major components present in lignocellulosic as well as algal biomass were studied independently in a thermo-gravimetric analyzer, using model compounds. From those studies, we have established that, with algae and oil seed feed stocks, triglycerides degrade at distinctly higher temperatures (T>350 C) compared to both protein and carbohydrate fractions (T ~ 250-350 C). Similar trend was not seen for lignocellulosic biomass, where degradation temperature interval of lignin overlapped with that of carbohydrates. This unique trend observed for algal biomass (and oil seeds) can be exploited in multiple ways. First, it permits to separately collect high value triglyceride degradation products not contaminated with N-compounds from protein and oxygenates from carbohydrates; this observation formed the basis of a novel "pyrolytic fractionation technique" developed in this thesis. Second, it led to the development of a new and simple analytical method for rapid estimation of the triglyceride content of oleaginous feed stocks. Pyrolytic fractionation is a two-step pyrolysis approach that can be implemented for oleaginous feed stocks (algae and oil-seeds) to separately recover triglyceride degradation products as a "high-quality" bio-oil fraction. The first step is a low-temperature pyrolysis (T ~ 300-320 C) to produce bio-oils from degradation of protein and carbohydrate fractions. Solid residues left behind can subsequently be subjected to a second higher temperature pyrolysis (T ~ 420-430 C) to volatilize and/or degrade triglycerides to produce fatty acids and their derivatives (such as mono-, di- and tri-glycerides) and long chain hydrocarbons. Proof-of-concept micro-pyrolyser (Pyroprobe) and lab-scale fixed-bed experiments were performed using oleaginous algae (Chlorella Sp.) to establish pyrolytic fractionation technique and also to determine the yields of triglyceride-specific bio-oils. As expected, triglyceride-specific bio-oils have hydrocarbons and free fatty acids that were nearly free of water, organic acids and carbohydrate degradation products. Another unique feature of the fractional pyrolysis method is that it allows upgrading of the triglyceride-specific bio-oil vapors via in situ gas-phase hydro-deoxygenation to drop-in fuels (hydrocarbons), without the need to condense the vapors. Similarly, these vapors can also be converted to other value-added products such as fatty acid methyl esters and amides though efficient catalytic and non-catalytic in situ gas-phase conversion methods. Energy requirements for this new pyrolytic fractionation method were also assessed, using energy estimates for the individual steps obtained via differential scanning calorimetry experiments. A comparison of these energy needs against those of alternative thermal processing methods of algae (hydro-thermal processing) proposed in the literature established the viability of this new method. Finally, a new TGA-based analytical method was developed in this thesis for rapid quantification of the triglyceride content of oleaginous feed stocks, by exploiting the non-overlapping thermal degradation range of triglycerides and the other major components.

Committee:

Sasidhar Varanasi (Committee Chair); Sridhar Viamajala (Committee Co-Chair); Glenn Lipscomb (Committee Member); Arunan Nadarajah (Committee Member); Thomas Bridgeman (Committee Member)

Subjects:

Alternative Energy; Chemical Engineering; Energy; Sustainability

Keywords:

Biomass, Pyrolysis, Algae, Oleaginous algae, Microalgae, Lignocellulosic feedstocks, Biomass fractionation, Pyrolytic fractionation, Triglycerides, Biodiesel

Liu, ZhouyangNitrogen Removal and Lipid Production from Secondary Wastewater Using Green Alga Chlorella vulgaris
MS, University of Cincinnati, 2012, Engineering and Applied Science: Environmental Engineering
Increasing nitrogen discharges into natural water systems have caused more frequent eutrophication and other water quality issues. Microalgae are fast growing photosynthetic microorganisms that can assimilate nitrogen and phosphorus from water. Also, lipid content of certain strains of microalgae could reach over 60%, making microalgae excellent feedstock for biodiesel production. Green alga Chlorella vulgaris was tested for nitrogen removal and lipids production using secondary wastewater from municipal wastewater treatment plant. Around 60% of NH3-Nitrogen was removed after 48 hour, and removal rate was further increased to 75% when carbon dioxide gas was added periodically to control pH. When more active algae seeds were used, NH3-Nigrogen removal rate of 97.1% was achieved. Chlorella vulgaris was also very effective for removing low concentration of phosphate from secondary wastewater. When growing at normal conditions, Chlorella vulgaris contained more polar lipid than neutral lipid. Total lipid content of Chlorella vulgaris ranged from 10.6% to 14%, and fatty acids were mainly C16 and C18, making it good biodiesel stock. A freshwater microalgae survey in southwest Ohio was also conducted to provide useful information for future outdoor algae cultivation. 24 genera of cyanobacteria and 49 genera of eukaryotic algae were identified, with Synechococcus sp. and Cryptomonas sp. being the predominant prokaryotic and eukaryotic microalgae, respectively.

Committee:

Joo Youp Lee, PhD (Committee Chair); Timothy Keener, PhD (Committee Member); Mingming Lu, PhD (Committee Member)

Subjects:

Environmental Engineering

Keywords:

Chlorella vugaris;nitrogen removal;secondary wastewater;lipid;biodiesel;algae;

Anthony, Renil J.Solvent Extraction of Lipids from Microalgae
Master of Science (MS), Ohio University, 2010, Mechanical Engineering (Engineering and Technology)
Algae are a favorable feedstock for biodiesel due to their high oil content and fast growth rate. The average oil content has been found to be 20-50% of dry weight. Solvent lipid extraction efficiency from algae is strain specific and with the focus on neutral lipids, four non-polar solvents were tested on Oocystis sp. Methylene chloride, hexane, diethyl ether and cyclohexane were chosen, and the extractions performed in a soxhlet apparatus. The lipid extracts were derivatized and analyzed using a combination of Gas Chromatography-Mass Spectrometry. All four solvent extracts showed the same composition of hexadecanoic acid methyl ester (C16:0), linoleic acid methyl ester(C18:2) and linolenic acid methyl ester (C18:3) with the same % wt composition. Among the four, methylene chloride proved to be the most efficient solvent for Oocystis sp. with a total neutral lipid recovery of 0.25% of dry weight followed by diethyl ether,cyclohexane and hexane. The results question the use of the algal strain Oocystis sp. for biofuels. The lipid productivity in Oocystis sp. would need to be verified and a more efficient solvent and/or extraction technique identified, or an algal strain having higher lipid productivity should be employed for biofuel feedstock.

Committee:

Benjamin Stuart, J (Advisor); David Bayless, J (Committee Member); Guy Riefler, R (Committee Member); Morgan Vis (Committee Member)

Subjects:

Botany; Energy; Engineering; Environmental Science; Mechanical Engineering

Keywords:

Algae; Biodiesel; Oocystis; Solvent Extraction; Soxhlet; Microalgae

Tu, QingshiAssessment of Selected Sustainability Aspects of Biodiesel Production: Water and Waste Conservation
MS, University of Cincinnati, 2012, Engineering and Applied Science: Environmental Engineering

Biodiesel has been in commercial use for more than a decade with several known benefits: reducing the nation's reliance on petroleum import, significant reduction in the emission of air pollutants and green house gases (GHGs), and comparable fuel properties to the petroleum diesel.

However, expansion of the biodiesel industry has also resulted in some concerns. As an example, the ¿¿¿¿¿¿¿food vs. fuel¿¿¿¿¿¿¿ debate reflects the competition of biodiesel with food supply when edible seed-oils, such as soybean oil, are used for more profitable production. In order for the biodiesel industry to continue thriving in the future, various governments and organizations have imposed and suggested an array of sustainability factors for biodiesel supply chain, such as land use, water consumption, waste management, cost and availability of feedstocks, etc.

This study addressed two major sustainability aspects regarding biodiesel production: (1) water consumption, and (2) utilization of waste materials. In detail, the following topics were investigated: (1) characterization of water consumption by soybean-derived biodiesel in plant growth and fuel production; (2) parametric study of reducing FFA (free fatty acid) in waste cooking oil; and (3) a preliminary evaluation on the utilization of waste coffee ground as biodiesel feedstock and purification material.

Water consumption from biodiesel process was characterized as three stages: plant growth, soybean processing and biodiesel production. Result showed that the nationwide average irrigation accounted for 61.78 gallons of water per gallon of soybean biodiesel while soybean processing (0.17 gal/gal) and biodiesel production (0.36 gal/gal) stages consumed much less. A state-by-state analysis for irrigation water indicated that the water consumption was highly dependent on the location and climate. Overall, on a nationwide basis, the total water consumption for making biodiesel from soybean was approximately 808.7 million gallons water per year.

In general, feedstock can account for up to 80% of the total cost for biodiesel production. This offers potentials for low cost and even waste materials, such as animal fats, waste cooking oil (WCO), and trap grease (brown grease). However, the high FFA content (>1 wt%) in these waste materials requires pretreatment prior to transesterification . Therefore, a parametric study on FFA reduction in WCO was performed to study the optimum conditions for FFA pretreatment. WCO with FFA level of 5¿¿¿¿0.5 wt% was treated by acid catalytic esterificiation using sulfuric acid (H2SO4). The influence of temperature, methanol-to-FFA molar ratio, and catalyst concentration on the conversion rate was investigated. Results indicated that the optimal condition was 60¿¿¿¿5¿¿¿¿C, 40:1 methanol-to-FFA molar ratio, and 12.5 wt% H2SO4.

Thirdly, a preliminary study was performed to investigate the feasibility of using waste coffee grounds (WCG) as both an oil source and purification material for biodiesel production. Results showed that the oil content of WCG was around 10 wt%. In addition, the post-extraction WCGs were found to be effective in removing impurities from crude biodiesel, such as free glycerin, methanol and metal ions. Results suggested that WCG may be comparable in purification capability to commercial materials. The use of waste as feedstock and purification material can greatly promote the sustainability of biodiesel production by lowering overall production cost, reducing waste generation (less/no additional purification material needed) and minimizing life cycle environmental impact (recycling/reusing wastes in each stage of the production life cycle).

Committee:

Mingming Lu, PhD (Committee Chair); Drew McAvoy, PhD (Committee Member); Jeffrey Yang, PhD (Committee Member); Joo Youp Lee, PhD (Committee Member)

Keywords:

biodiesel;Sustainability;Water consumption;FFA;Waste coffee grounds;Purification;

Hricik, Laurel BrookeAN INTERNSHIP WITH THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY PACIFIC SOUTHWEST REGION WASTE MANAGEMENT DIVISION
Master of Environmental Science, Miami University, 2007, Environmental Sciences
This paper details various projects conducted at the United States Environmental Protection Agency Pacific Southwest Office located in San Francisco, California from June 2006 through December 2006. During this six-month internship, my primary role involved creating the EPA’s first regional biodiesel website and actively participating in the creation of a partnership between EPA Region 9 and the University of California. This report details my experiences, the information associated with them, as well as my reflections on my internship.

Committee:

Adolph Greenberg (Advisor)

Keywords:

Biodiesel; US EPA Region 9; Department of Defense

Ibrahim, UmarCharacterization of Biodiesel Blends Effects on Aftertreatment Systems and Aftertreatment-based Blend Level Estimation
Doctor of Philosophy, The Ohio State University, 2016, Mechanical Engineering
Biodiesel is an alternative renewable diesel fuel that has the potential to reduce dependence on fossil oil. Use of biodiesel in diesel engines results in lower emissions of carbon monoxide (CO), total hydrocarbons (THC), and particulate matter (PM) though emissions of nitrogen oxides (NOx) may increase. Even though biodiesel is similar enough to petroleum diesel that it is considered an alternative to it, still, there exist certain important differences in properties of two fuels which necessitate special considerations to optimally use biodiesel with modern diesel engines. Biodiesel is an oxygenated fuel and has higher density but lower energy density compared to petroleum diesel, which can significantly affect engine performance and emissions if not taken into account. Therefore onboard detecting the fuel type supplied to an engine is an important step towards mitigating negative impacts of fuel change. In the first part of this work, an investigation is made into the effects of pure biodiesel and fossil diesel fuels on common-rail diesel engine and diesel aftertreatment system during active regeneration of diesel particulate filter (DPF). Impact of variation of parameters such as post injection start of injection (SOI), injection rate and number of injections on engine performance and emissions along with diesel oxidation catalyst (DOC) performance is evaluated. Among other findings it was observed that biodiesel results in lower engine-out THC and CO emissions along with lower engine-out temperature. It was also observed that DOC conversion efficiencies for both THC and CO reduce for biodiesel compared to fossil diesel fuel. To capture this difference in response to fuel type used with the engine a 0-D thermal model of DOC was developed for estimation of heat energy released inside DOC from oxidation of THC and CO. The model is then applied to estimate biodiesel blend level for various engine operating conditions with an error margin of 10%. In subsequent work, an experimental study was conducted to evaluate the use of difference of CO emissions with high rate of exhaust gas recirculation (EGR) rate for biodiesel blend estimation using DOC to detect energy release inside DOC from oxidation of CO. It was found out that oxygen content and lower heating values of fuel along with fuel injection timing are the main factors that influence quantity of CO emissions. The study also suggested that in order to use the proposed blend estimation technique a quantitative model for CO emissions taking into account fuel oxygen content, fuel heating value, EGR valve opening, and injection timing is required.

Committee:

Junmin Wang (Advisor)

Subjects:

Mechanical Engineering

Keywords:

diesel engine, biodiesel, alternative fuels, aftertreatment systems, post injection

Sinha, AmitStudy of Hydrocarbon and Carbonyl Compound Emissions from Combustion of Biodiesel Blends using Plasma and Swirl Stabilized Combustors
MS, University of Cincinnati, 2016, Engineering and Applied Science: Environmental Engineering

The thesis investigated carbonyl and hydrocarbon emissions from biodiesel blends with diesel or Α fuel. Different technologies were used to improve biodiesel combustion. Plasma was used to improve diesel–biodiesel combustion and improved swirl–stabilized fuel injectors were used to improve combustion from biodiesel–jet fuel. The diesel– biodiesel blended fuels′ combustion ⟨hydrocarbons and carbonyl compounds⟩ emissions were analyzed and interpreted for plasma on and plasma off conditions. Plasma assisted combustion ⟨PAC⟩ is known to improve fuel efficiency, enhance and stabilize combustion performance and enhance fuel reforming. Fuel–rich fuel⁄air mixture is introduced into a plasma field and further downstream, the secondary air is added resulting in overall fuel– lean condition mixture, and properly hold the flame inside the combustion chamber. It is found that the total hydrocarbons emission index ⟨EI⟩ & total carbonyls EI is lower for plasma on condition than for plasma off condition for a given fuel–air equivalence ratio ⟨Φ⟩. For plasma on, flame is sustained over a larger lean Φ than plasma off. The major carbonyls detected were acetone and acrolein.

Straight⁄ branched alkanes & methyl esters were the dominant hydrocarbons identified. The plasma′s thermal and kinetic effects helped in reducing the formation of incomplete oxidation products and extending the lean flammability limit; hence enhancing the overall combustion performance. Reduced hydrocarbons and carbonyls emissions from plasma can be used to further support the use of plasma as an environment friendly combustion technology even for viscous fuels like diesel and B20. A swirl stabilized pilot nozzle ⟨in atmospheric rig⟩ and a low–emission Multi–nozzle lean direct injection ⟨MLDI⟩ combustor ⟨in pressurized rig⟩ was used to burn pure Α fuel as well as its blends with biodiesel ⟨BJ20 & BJ50⟩ to compare the emissions. The various aspects of this combustor design have the goal of reducing residence time, resulting in lower overall nitrogen dioxide formation by the thermal pathway. In atmospheric rig, biodiesel blends ⟨BJ20 & BJ50⟩ yielded less carbonyls and hydrocarbons emissions compared to Α fuel for fuel–rich conditions. For pressurized rig, as pressure across a single stage nozzle ⟨pilot⟩ was increased, total carbonyls EI and hydrocarbons EI decreased for both BJ20 and Α, for same mixed combustor temperature. The minimum value was recorded for highest power operating condition i.e. multi– stage nozzles. Α, however, tended to produce lesser hydrocarbons and carbonyls compared to BJ20. The main carbonyls identified were acetone, formaldehyde, acetaldehyde, benzaldehyde & acrolein while alkanes, hexa⁄ octadecanoic acids, tridecanol & methyl esters ⟨only observed for BJ20 in pressurized rig⟩ were the dominant hydrocarbons emitted. Excess unburned hydrocarbons may well be due to unsuitability of the small nozzles in this experiment for biodiesel blends.

Committee:

Mingming| Lu (Committee Chair); Timothy Keener (Committee Member); Jongguen| Lee (Committee Member); David Munday (Committee Member)

Subjects:

Environmental Engineering

Keywords:

biodiesel;jet fuel;diesel;carbonyls and hydrocarbons;plasma;nozzles

Herron, Trevor PAn Internship with the Zero Waste Alliance
Master of Environmental Science, Miami University, 2005, Environmental Sciences
This paper reports on an internship at the Zero Waste Alliance in Portland, Oregon. The Zero Waste Alliance is a non-profit organization that provides sustainability consultation for public and private organizations. The report focuses on three main projects and the professional development achieved as a result of this work. The main projects consist of a chemical assessment and ranking project for the Port of Portland, a waste management project for Widmer Brewing Company, and research of biodiesel fuels for a biodiesel coop.

Committee:

Sandra Woy-Hazleton (Advisor)

Subjects:

Environmental Sciences

Keywords:

Biodiesel; Waste management; Sustainability; Environmental non-profits; Portland Oregon

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