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Process control and instrumentation methods for biomass fluidized bed gasifier operationCampbell, William Allan 04 June 2010
A fluidized bed gasification (FBG) pilot plant was designed and constructed at the University of Saskatchewan Chemical Engineering Department Fluidization Laboratory. FBG is a thermo-chemical method for converting solid biomass to a gaseous fuel, termed syngas. Several instrumentation and control issues were particularly challenging with this pilot plant, including development of the fuel feeding system, pressure measurement of high temperature fluids, and metering of steam as a process reactant.<p>
The fuel feeding system was tested using MBM (meat and bone meal) to determine the output rate stability, and predictability and measurability of the system as the components in the fuel feeding system were integrated. The fuel feeding system that was tested included a 150 mm primary metering screw conveyor, a 150 mm rotary airlock, and a 50 mm secondary injection screw conveyor. Each component of the system was fitted with a 3-phase electric motor and a variable speed drive to allow for a variable output rate. The weighing system that was integral to the metering conveyor was tested as well, but upon pressurizing the metering conveyor and hopper, the weighing system sustained an unreasonable amount of noise. Integrating a pneumatic injection nozzle with the injection conveyor was found to work effectively both under ambient temperatures and hot FBG conditions up to 725oC. Above 725oC, it was found that the test fuel would char and coat the nozzle, causing it to plug. Testing of the feeding system with the injection nozzle removed illustrated that the system could work well without it. It was determined that the injection conveyor speed to metering conveyor speed ratio that should be used for this system was 1:110 for absolute rotational speeds, or 1:1 of the full conveyor speeds. The complete system, including the injection nozzle, was analyzed and determined to produce a fuel output rate (FS) for % speeds from 5-25%, which roughly corresponded to the desired plant fuel feed rate of 1-5 g/s.<p>
Techniques for remote pressure measurement of fluidized beds were examined as well, including the use of long tubes to cool hot gases and filters for blocking solid particles. The pressure measurement delay of these techniques was examined in comparison to a direct local measurement. This was conducted by comparing the pressure readings from two identical sensors; one mounted directly to a manifold, and the other mounted via a variable assembly (comprised of a variable length of 6.35 mm (1/4") PE tubing and a porous plate filter). Assemblies without a porous plate were found to have a minimal delay of up to 0.303 seconds for 30 m length of PE impulse tubing. More significant delays were found for systems using both a 10 media grade porous plate filter and impulse tubing; a 3 m tube length with filter has a delay of up to 0.221 s, and a 30 m impulse tube combined with the filter has a measurement delay of up to 1.915 s, a significant delay in cases where high-frequency analysis of pressure is used for bed agglomeration prediction, or systems where fast response is required to changing pressure conditions.<p>
Additionally, a steam flow measurement system using an orifice plate and differential pressure sensor was installed and calibrated. By collecting time-based steam samples and process data, the physical system coefficients were determined for this system, allowing for steam flow measurement, accurate within 5% over a flow range of 0.5 to 2.0 g/s.
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Solid-state anaerobic digestion for integrated ethanol productionLung, Patricia 09 November 2011
Anaerobic digestion (AD) is a biochemical process consisting of the microbiological conversion of organic materials for the purpose of generating biogas. Biogas is typically composed of 50 to 70% methane (CH4) and 50 to 30% carbon dioxide (CO2) with trace amounts of other compounds. Anaerobic digestion technology is a bioprocessing technology that has the potential to be integrated into an ethanol facility to further capture energy, in the form of methane gas, for use in a combined heat and power (CHP) generator or for integration into the natural gas pipeline grid after undergoing an upgrading process. The most simplistic design of an AD system is the solid state digester (SSD) which is able to process very high solids content materials (greater than 15% solids). A SSD has the potential to be utilized as a manure management system in a beef cattle feedlot and it has the potential to integrate seamlessly into a combined ethanol- feedlot operation to capitalize on the eco-cluster concept in bioenergy production.
This thesis investigates the biogas and digestate composition seen from four material blends in a solid-state digester (SSD) system operated as a batch reactor. Wet distiller grains (WDG) from a grain ethanol process and cattle manure were the substrates investigated. To assess the biogas composition the system was operated over a period of time to achieve a quasi steady state within the microbial population to maximize the CH4 concentration in the biogas composition. To assess the robustness of the microbial population within each substrate blend, the biogas concentrations were measured over three cycle periods where a portion of the used substrate was replaced with an equal amount of fresh substrate. The digestate composition was analyzed at the end of each of the cycles and compared with the raw substrate to determine changes in solids and nutrient values.
The biogas production calculated in this study determined 0.17, 0.21, 0.18, and 0.12L per gram (VS) within 100% WDG, 75%WDG and 25% manure, 25% WDG and 75% manure and the 100% manure substrate (Group 1 through 4) respectively, averaged over all three digestion cycles. At the end of three cycles of digestion the biogas within the substrate blend containing 25% WDG and 75% manure (Group 3) achieved a measured CH4 concentration of 49% and the biogas within the 100% manure substrate (Group 4) achieved a 59% concentration of CH4. The duration for each of Group 3 and Group 4 to achieve the production of viable biogas was 100 and 90 days of operation respectively. Thus it can be concluded that a SSD system start up duration will be between three and four months in duration.
The gas data gathered in this research study indicates Group 3 had the most robust methanogenic culture established as it has the lowest overall N2 and CO2 concentration detected in the biogas, and the most consistent performance of CH4 production during each cycle. The investigation conducted on the nutrient data gathered in this research supports the conclusion drawn from the gas data regarding the overall methanogenic performance of the substrate blends. The nutrient data for Group 3 maintained an average carbon to nitrogen (C:N) ratio of 25:1 over all three digestion cycles. The nitrogen, phosphorous, potassium, and sulphur components of the manure fertilizer value were maintained through the digestion process of this investigation thus typical manure application rate calculations are applicable when field applying digestate.
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Comparison of Biological and Thermal (Pyrolysis) Pathways for Conversion of Lignocellulose to BiofuelsImam, Tahmina 1983- 14 March 2013 (has links)
Because of the limited supply of imported crude oil and environmental degradation, renewable energy is becoming commercially feasible and environmentally desirable. In this research, biological and thermal (pyrolysis) conversion pathways for biofuel production from lignocellulosic feedstocks were compared. For biological conversions of sorghum, ethanol yield was improved using M81-E variety (0.072 g/g juice) over Umbrella (0.065 g/g juice) for first-generation biomass (sorghum juice), and 0.042 g/g sorghum was obtained from the cellulosic portion of second-generation biomass. When ultrasonication was combined with hot water pretreatment, yields increased by 15% and 7% for cellulose to glucose, and hemicellulose to pentose, respectively. Ethanol yield was 10% higher when this pretreatment was combined with Accellerase 1500+XC for saccharification. Biological conversion yielded 1,600?2,300 L ethanol/ha for first-generation biomass, and 4,300?4,500 L ethanol/ha from lignocellulosic biomass.
For thermal (pyrolysis) conversion of lignocellulosic switchgrass at 600 degrees C, product yield was 37% bio-oil, 26% syngas, and 25% bio-char. At 400 degrees C, product yield was 22% bio-oil, 8% syngas, and 56% bio-char. Bio-oil from pyrolysis was highly oxygenated (37 wt%). It required chemical transformation to increase its volatility and thermal stability, and to reduce its viscosity by removing objectionable oxygen, so the product could be used as transportation fuel (gasoline). As a consequence of upgrading bio-oil by catalytic hydrogenation, bio-oil oxygen decreased from 37?2 wt%, carbon increased from 50?83 wt%, hydrogen increased from 9?15 wt% and heating value increased from 36?46 MJ/kg, resulting in a fuel that was comparable to gasoline. The upgraded product passed the thermal stability test when kept under an oxygen-rich environment. The upgraded product consisted of 14.8% parrafins, 21.7% iso-parrafins, 3% napthene, 42.6% aromatics, 4.7% olefin, 4.7% DMF, 8% alcohol, and 0.6% ketone on a mass basis.
Comparing the two pathways, biological conversion had 11 wt% ethanol yield from sorghum, and thermal conversion had 13 wt% gasoline yield from switchgrass. For process efficiency, thermal conversion had 35% energy loss versus 45% energy loss for biological conversions. For the biological pathway, ethanol cost was $2.5/gallon ($4/gallon, gasoline equivalent), whereas for the thermal pathway, switchgrass gasoline cost was $3.7/gallon, both with 15% before tax profit.
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Solid-state anaerobic digestion for integrated ethanol productionLung, Patricia 09 November 2011 (has links)
Anaerobic digestion (AD) is a biochemical process consisting of the microbiological conversion of organic materials for the purpose of generating biogas. Biogas is typically composed of 50 to 70% methane (CH4) and 50 to 30% carbon dioxide (CO2) with trace amounts of other compounds. Anaerobic digestion technology is a bioprocessing technology that has the potential to be integrated into an ethanol facility to further capture energy, in the form of methane gas, for use in a combined heat and power (CHP) generator or for integration into the natural gas pipeline grid after undergoing an upgrading process. The most simplistic design of an AD system is the solid state digester (SSD) which is able to process very high solids content materials (greater than 15% solids). A SSD has the potential to be utilized as a manure management system in a beef cattle feedlot and it has the potential to integrate seamlessly into a combined ethanol- feedlot operation to capitalize on the eco-cluster concept in bioenergy production.
This thesis investigates the biogas and digestate composition seen from four material blends in a solid-state digester (SSD) system operated as a batch reactor. Wet distiller grains (WDG) from a grain ethanol process and cattle manure were the substrates investigated. To assess the biogas composition the system was operated over a period of time to achieve a quasi steady state within the microbial population to maximize the CH4 concentration in the biogas composition. To assess the robustness of the microbial population within each substrate blend, the biogas concentrations were measured over three cycle periods where a portion of the used substrate was replaced with an equal amount of fresh substrate. The digestate composition was analyzed at the end of each of the cycles and compared with the raw substrate to determine changes in solids and nutrient values.
The biogas production calculated in this study determined 0.17, 0.21, 0.18, and 0.12L per gram (VS) within 100% WDG, 75%WDG and 25% manure, 25% WDG and 75% manure and the 100% manure substrate (Group 1 through 4) respectively, averaged over all three digestion cycles. At the end of three cycles of digestion the biogas within the substrate blend containing 25% WDG and 75% manure (Group 3) achieved a measured CH4 concentration of 49% and the biogas within the 100% manure substrate (Group 4) achieved a 59% concentration of CH4. The duration for each of Group 3 and Group 4 to achieve the production of viable biogas was 100 and 90 days of operation respectively. Thus it can be concluded that a SSD system start up duration will be between three and four months in duration.
The gas data gathered in this research study indicates Group 3 had the most robust methanogenic culture established as it has the lowest overall N2 and CO2 concentration detected in the biogas, and the most consistent performance of CH4 production during each cycle. The investigation conducted on the nutrient data gathered in this research supports the conclusion drawn from the gas data regarding the overall methanogenic performance of the substrate blends. The nutrient data for Group 3 maintained an average carbon to nitrogen (C:N) ratio of 25:1 over all three digestion cycles. The nitrogen, phosphorous, potassium, and sulphur components of the manure fertilizer value were maintained through the digestion process of this investigation thus typical manure application rate calculations are applicable when field applying digestate.
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Process control and instrumentation methods for biomass fluidized bed gasifier operationCampbell, William Allan 04 June 2010 (has links)
A fluidized bed gasification (FBG) pilot plant was designed and constructed at the University of Saskatchewan Chemical Engineering Department Fluidization Laboratory. FBG is a thermo-chemical method for converting solid biomass to a gaseous fuel, termed syngas. Several instrumentation and control issues were particularly challenging with this pilot plant, including development of the fuel feeding system, pressure measurement of high temperature fluids, and metering of steam as a process reactant.<p>
The fuel feeding system was tested using MBM (meat and bone meal) to determine the output rate stability, and predictability and measurability of the system as the components in the fuel feeding system were integrated. The fuel feeding system that was tested included a 150 mm primary metering screw conveyor, a 150 mm rotary airlock, and a 50 mm secondary injection screw conveyor. Each component of the system was fitted with a 3-phase electric motor and a variable speed drive to allow for a variable output rate. The weighing system that was integral to the metering conveyor was tested as well, but upon pressurizing the metering conveyor and hopper, the weighing system sustained an unreasonable amount of noise. Integrating a pneumatic injection nozzle with the injection conveyor was found to work effectively both under ambient temperatures and hot FBG conditions up to 725oC. Above 725oC, it was found that the test fuel would char and coat the nozzle, causing it to plug. Testing of the feeding system with the injection nozzle removed illustrated that the system could work well without it. It was determined that the injection conveyor speed to metering conveyor speed ratio that should be used for this system was 1:110 for absolute rotational speeds, or 1:1 of the full conveyor speeds. The complete system, including the injection nozzle, was analyzed and determined to produce a fuel output rate (FS) for % speeds from 5-25%, which roughly corresponded to the desired plant fuel feed rate of 1-5 g/s.<p>
Techniques for remote pressure measurement of fluidized beds were examined as well, including the use of long tubes to cool hot gases and filters for blocking solid particles. The pressure measurement delay of these techniques was examined in comparison to a direct local measurement. This was conducted by comparing the pressure readings from two identical sensors; one mounted directly to a manifold, and the other mounted via a variable assembly (comprised of a variable length of 6.35 mm (1/4") PE tubing and a porous plate filter). Assemblies without a porous plate were found to have a minimal delay of up to 0.303 seconds for 30 m length of PE impulse tubing. More significant delays were found for systems using both a 10 media grade porous plate filter and impulse tubing; a 3 m tube length with filter has a delay of up to 0.221 s, and a 30 m impulse tube combined with the filter has a measurement delay of up to 1.915 s, a significant delay in cases where high-frequency analysis of pressure is used for bed agglomeration prediction, or systems where fast response is required to changing pressure conditions.<p>
Additionally, a steam flow measurement system using an orifice plate and differential pressure sensor was installed and calibrated. By collecting time-based steam samples and process data, the physical system coefficients were determined for this system, allowing for steam flow measurement, accurate within 5% over a flow range of 0.5 to 2.0 g/s.
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Essays on Economic and Environmental Analysis of Taiwanese Bioenergy Production on Set-Aside LandKung, Chih-Chun 2010 December 1900 (has links)
Domestic production of bioenergy by utilizing set-aside land in Taiwan can reduce
Taiwan’s reliance on expensive and politically insecure foreign fossil fuels while also
reducing the combustion of fossil fuels, which emit substantial amounts of greenhouse
gases. After joining the World Trade Organization, Taiwan’s agricultural sector idled
about one-third of the national cropland, hereafter called “set-aside land”. This
potentially provides the land base for Taiwan to develop a bioenergy industry. This
dissertation examines Taiwan’s potential for bioenergy production using feedstocks
grown on set-aside land and discusses the consequent effects on Taiwan’s energy
security plus benefits and greenhouse gas (GHG) emissions.
The Taiwan Agricultural Sector Model (TASM) was used to simulate different
agricultural policies related to bioenergy production. To do this simulation the TASM
model was extended to include additional bioenergy production possibilities and GHG
accounting. We find that Taiwan’s bioenergy production portfolio depends on prices of
ethanol, electricity and GHG. When GHG prices go up, ethanol production decreases and electricity production increases because of the relatively stronger GHG offset power
of biopower.
Results from this pyrolysis study are then incorporated into the TASM model.
Biochar from pyrolysis can be used in two ways: burn it or use it as a soil amendment.
Considering both of these different uses of biochar, we examine bioenergy production
and GHG offset to see to what extent Taiwan gets energy security benefits from the
pyrolysis technology and how it contributes to climate change mitigation. Furthermore,
by examining ethanol, electricity and pyrolysis together in the same framework, we are
able to see how they affect each other under different GHG prices, coal prices and
ethanol prices. Results show that ethanol is driven out by pyrolysis-based electricity
when GHG price is high. We also find that when biochar is hauled back to the rice fields,
GHG emission reduction is higher than that when biochar is burned for electricity;
however, national electricity production is consequently higher when biochar is burned.
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Assessing Available Woody Plant Biomass on Rangelands with Lidar and Multispectral Remote SensingKu, Nian-Wei 2011 May 1900 (has links)
The majority of biofuels are produced from corn and grain. The drawback to these sources of biofuels is the vast amount of cultivated land needed to produce substantial amounts of biofuel, potentially increasing the price of food and livestock products. Mesquite trees, a type of woody plant, are a proven source of bioenergy feedstock found on semi-arid lands. The overall objectives of this study were to develop algorithms for determining woody plant biomass on rangelands in Texas at plot-level using terrestrial lidar and at the local scale by integrating reference biomass and multispectral imagery.
Terrestrial lidar offers a more efficient method for estimating biomass than traditional field measurements. Variables from the terrestrial lidar point cloud were compared to ground measurements of biomass to find a best fitting regression model. Two processing methods were investigated for analyzing the lidar point cloud data, namely: 1) percentile height statistics and 2) a height bin approach. Regression models were developed for variables obtained through each processing technique for estimating woody plant, above-ground biomass. Regression models were able to explain 81 percent and 77 percent of the variance associated with the aboveground biomass using percentile height statistics and height bins, respectively. The aboveground biomass map was generated by using the cokriging interpolation method with NDVI and ground biomass data. According to cross-validation, ordinary cokriging estimated biomass accurately (R^2 = 0.99). The results of this study revealed that terrestrial lidar can be used to accurately and efficiently estimate the aboveground biomass of mesquite trees in a semi-arid environment at plot level. Moreover, spatial interpolation techniques proved useful in scaling up biomass estimates to local scale.
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Thin film nanoporous silica and graphene based biofuel cells (iBFCs) for low-power implantable medical device applicationsSharma, Tushar 23 February 2011 (has links)
This thesis describes the fabrication and characterization of an inorganic catalyst based glucose Biofuel cell using nanoporous (mesoporous) silica thin-film as a functional membrane. The desired use of nanoporous silica based biofuel cell is for a blood vessel implantable device. Blood vessel implantable Biofuel Cells (iBFCs) are subjected to higher glucose concentrations and blood flow rates. However, reduction in the implant thickness is critical for the intra-vascular implantable Biofuel cells. Platinum thin-film (thickness: 25 nm) deposited on Silicon substrate (500 [mu]m) served as the anode while Graphene pressed on Stainless steel mesh (175 [mu]m) was used as the cathode. Control experiments involved the use of surfactant-coated polypropylene membrane (50 [mu]m) and Activated Carbon (198 [mu]m) electrodes. Preliminary results show that nanoporous silica thin film (270 nm) is capable of replacing the conventional polymer based membranes with an increased power density output of as high as 10 [mu]W/cm2 under physiological conditions. in-vitro (5 [mu]W/cm2) and in-vivo (10 [mu]W/cm2) experiments demonstrate the potential of ultra-thin iBFCs towards powering future medical implants. / text
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Evaluation of Nitrogen Fertilization in C4 Grasses Grown for BioenergyEngbers, Heather M 09 May 2012 (has links)
Nitrogen fertilization has the potential to significantly affect yield, nutrient concentration and removal and overall stand longevity of C4 grasses grown for bioenergy production. While most studies report that these grasses need little to no fertilizer inputs to maximize yield, no specific recommendations have been given for fertilizer requirements across a wide range of C4 perennial grass species, cultivars, harvest timings and N application rates. Two field trials were established in the summer of 2008 in Ridgetown and Elora, Ontario to compare 4 Miscanthus (M. sinensis and M. sacchariflorus crosses; Nagara-116 and Amuri-114, and Miscanthus x giganteus; M1 Select and Polish), 2 switchgrass (Panicum virgatum L.; Cave-in-rock and Shelter) and 2 big bluestem varieties (Andropogon gerardii Vitman; Prairie view and Southlow), 4 nitrogen fertilization rates (0, 40, 80, and 160 kg N ha-1) and 2 harvest timings (fall vs. spring harvest). Plots were harvested in the fall of 2009 and spring and fall of 2010. Yield response to N fertilization varied by location, species and year. In general, increasing N fertilization rates generated an increased yield response in all tested species. Different rates of N fertilization resulted in variable responses to N, P and K tissue concentrations and removal in switchgrass and Miscanthus. Tissue N concentrations and removal both increased with added N fertilization at both locations. In most cases N removal was the highest at the highest N application rate. Nitrogen concentrations were highest in the leaves and seed heads across species, N rates and locations. P and K concentrations and removal with increasing N fertilization in the whole plant and in individual plant parts did not follow clear trends in either Miscanthus or switchgrass in both locations. Delaying harvest to spring reduced yield at both locations by 35-42% and 62-65% for Miscanthus and switchgrass, respectively. Yield losses by delaying harvesting to the spring were increased with higher rates of N fertilization. Delaying harvesting decreased N, P and K concentration and removal in most grasses and locations.
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Development of forest biorefining in Canada: overcoming the feedstock barrierBlair, M. Jean 08 January 2014 (has links)
The development of forest-based biorefineries has the potential to both provide a source of sustainable, low carbon fuel and increase the value drawn from wood residues to help revitalize the forest sector. There has been significant progress toward developing forest biorefining technologies, supported to some extent through government programs, though there are still several barriers to development. Realization of commercial-scale facilities however, will likely be limited by logistical constraints associated with maintaining a consistent supply of woody feedstock and the high capital cost of constructing the facility. To address this issue, mill clusters with sufficient processing capacity were located and evaluated for their suitability to house a forest biorefinery. Existing single-entity mill clusters in Canada were identified according to a set of criteria, and provide the basis for the analysis to determine feedstock supply costs and potential availability. The optimal biorefinery sites within each cluster were identified using a transportation module developed for this study and evaluated according to other factors that would affect the suitability of the site for a large scale forest biorefinery, such as access to markets, other available feedstocks and energy sources. There were four mill clusters identified in eastern Canada that have the potential to support a commercial forest biorefinery. A facility that is centrally located within one of the identified clusters would expect to have a feedstock cost ranging from approximately $95 to $110 per odt. A series of key informant interviews were carried out to further assess the cluster approach to forest biorefinery development. Interviewees generally agreed that the identified locations could potentially support a commercial biorefinery and suggested there are currently significant volumes of underutilized wood in these regions. Forest biorefinery development in the cluster regions, especially where there is mixed forest, should be further pursued. / Thesis (Master, Geography) -- Queen's University, 2013-12-30 17:39:57.326
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