Browsing by Subject "biomass"
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Item An analysis of producing ethanol and electric power from woody residues and agricultural crops in East Texas(Texas A&M University, 2007-09-17) Ismayilova, Rubaba MammadThe increasing U.S. dependence on imported oil; the contribution of fossil fuels to the greenhouse gas emissions and the climate change issue; the current level of energy prices and other environmental concerns have increased world interest in renewable energy sources. Biomass is a large, diverse, readily exploitable resource. This dissertation examines the biomass potential in Eastern Texas by examining a 44 county region. This examination considers the potential establishment of a 100-megawatt (MW) power plant and a 20 million gallon per year (MMGY) ethanol plant using lignocellulosic biomass. The biomass sources considered are switchgrass, sugarcane bagasse, and logging residues. In the case of electricity generation, co-firing scenarios are also investigated. The research analyzes the key indicators involved with economic costs and benefits, environmental and social impacts. The bioenergy production possibilities considered here were biofeedstock supported electric power and cellulosic ethanol production. The results were integrated into a comprehensive set of information that addresses the effects of biomass energy development in the region. The analysis indicates that none of the counties in East Texas have sufficient biomass to individually sustain either a 100% biomass fired power plant or the cellulosic ethanol plant. Such plants would only be feasible at the regional level. Co-firing biomass with coal, however, does provide a most attractive alternative for the study region. The results indicate further that basing the decision solely on economics of feedstock availability and costs would suggest that bioenergy, as a renewable energy, is not a viable energy alternative. Accounting for some environmental and social benefits accruing to the region from bioenergy production together with the feedstock economics, however, suggests that government subsidies, up to the amount of accruing benefits, could make the bioenergies an attractive business opportunity for local farmers and investors.Item An integrated approach for techno-economic and environmental analysis of energy from biomass and fossil fuels(Texas A&M University, 2007-04-25) Mohan, TanyaBiomass conversion into forms of energy is receiving current attention because of environmental, energy and agricultural concerns. The purpose of this thesis is to analyze the environmental, energy, economic, and technological aspects of using a form of biomass, switchgrass (panicum virgatum), as a partial or complete replacement for coal in power generation and cogeneration systems. To examine the effects of such a substitution, an environmental biocomplexity approach is used, wherein the agricultural, technological, economic, and environmental factors are addressed. In particular, lifecycle analysis (LCA) and a three-dimensional integrated economic, energy and environmental analysis is employed. The effectiveness of alternate technologies for switchgrass preparation, harvest and use in terms of greenhouse gas impact, cost and environmental implications is examined. Also, different scenarios of cofiring and biomass preparation pathways are investigated. Optimization of the total biomass power generation cost with minimum greenhouse gas effect is undertaken using mathematical programming for various alternate competitive biomass processing pathways. As a byproduct of this work a generic tool to optimize the cost and greenhouse gas emissions for allocation of fuel sources to the power generating sinks is developed. Further, this work discusses the sensitivity of the findings to varied cofiring ratios, coal prices, hauling distances, per acre yields, etc. Besides electricity generation in power plants, another viable alternative for reducing greenhouse gases (GHGs) is the utilization of biomass in conjunction with combined heat and power (CHP) in the process industries. This work addresses the utilization of biowaste or biomass source in a processing facility for CHP. A systematic algebraic procedure for targeting cogeneration potential ahead of detailed power generation network design is presented. The approach presented here effectively utilizes the biomass and biowaste sources as external fuel, and matches it with the use and dispatch of fuel sources within the process, heating and non-heating steam demands, and power generation. The concept of extractable energy coupled with flow balance via cascade diagram has been used as a basis to construct this approach. The work also discusses important economic factors and environmental policies required for the cost-effective utilization of biomass for electricity generation and CHP.Item Anaerobic fermentation of rice straw and chicken manure to carboxylic acids(Texas A&M University, 2007-04-25) Agbogbo, Frank KwesiIn this work, 80% lime-treated rice straw and 20% lime-treated chicken manure were used as substrates in rotary fermentors. Countercurrent fermentation was performed at various volatile solid loading rates (VSLR) and liquid residence times (LRT). The highest acid productivity of 1.69 g/(L????d) was at a total acid concentration of 32.4 g/L. The highest conversion and yield were 0.692 g VS digested/g VS fed and 0.29 g total acids/g VS fed, respectively. The continuum particle distribution model (CPDM) was used to predict product concentrations at various VSLR and LRT. CPDM predicted the experimental total acid concentration and conversion at an average error of 6.41% and 6.55%, respectively. A fixed-bed fermentation system was designed to perform pretreatment and fermentation in the same unit. High product concentrations (~48 g/L) as well as high conversions (0.741 g VS digested/g VS fed, F4, Train B) were obtained from the same fermentor. CPDM was extended to predict product concentrations in the fixed-bed fermentation system. The model gave a good estimate of the product concentrations and retention time. After biomass fermentation, the residue can be combusted to generate heat. For pretreatment purposes, the use of ash can replace lime. A study was performed using ash as a potential pretreatment agent. Ash from raw poplar wood was effective in pretreating poplar wood; however, ash from bagasse fermentation residues was not useful in pretreating bagasse. Previous modeling studies indicate that a conversion of 95% could be achieved with bagasse using countercurrent fermentation. Because lignin constitutes 13% of the dry weight of bagasse, this means lignin would have to be digested to obtain a conversion of 95%. Experiments on the fermentation of enzymatically liberated lignin from both poplar wood and bagasse do not show that solubilized lignin was fermented to organic acids by using a mixed culture of marine microorganisms. Two buffer systems (ammonium bicarbonate and calcium carbonate) were used to compare product concentrations of carboxylic acid fermentations using office paper and chicken manure. It has been demonstrated that the total product concentration using ammonium bicarbonate is almost double the product concentration using calcium carbonate.Item Application of Remote Sensing Technology and Ecological Modeling of Forest Carbon Stocks in Mt. Apo Natural Park, Philippines(2015-01-23) Leal, Ligaya RubasThis dissertation work explored the application of remote sensing technology for the assessment of forest carbon storage in Mt. Apo Natural Park. Biomass estimation is traditionally conducted using destructive sampling with high levels of uncertainty. A more accurate and non-destructive method for assessment of biomass level is imperative to characterize remaining forest cover. This research study aimed to: 1) examine the vegetation profile and estimate species-specific biomass of Mt. Apo Natural Park, 2) develop an algorithm to assess biomass in plot-level using a terrestrial lidar system (TLS), and 3) generate landscape-level biomass estimates using interferometric synthetic aperture radar (IFSAR). This research endeavors to provide answers to these questions: 1) how the 3 tropical allometries compare in estimating field collected species-level biomass and carbon stocks in three management zones?, 2) what are the significant terrestrial laser scanning-derived metrics to assess plot-level biomass?, and 3) to what degree of uncertainty can IFSAR estimate biomass at the landscape level? Field data was gathered from 1382 trees, covering 52 local species during fieldwork in July and August 2013. Twenty-six plots (30 m x 30 m) were sampled on three management zones: multiple use, strict protection and restoration. Local insurgency problems restricted the research team from sampling additional plots. Destructive sampling was not permitted inside the protected area, thus requiring biomass to be estimated via the use of referenced biomass from 3 allometric equations by relating tree height, diameter-at-breast height, and wood specificity volume. A vegetation profile across the park was generated using a canopy height map (CHM). Results showed that resampled IFSAR products can be used to characterize biomass and carbon storage at the landscape level. This research has demonstrated the adoption of IPCC?s Tier 2, a combination of field and remote sensing data in the assessment of available biomass levels in a tropical forest. The maps created can assist in providing information for biomass and carbon level in MANP for monitoring, reporting and verification in compliance with REDD requirements. Furthermore, this study can provide helpful information regarding policy implications for reforestation and afforestation activities. Results showed that resampled IFSAR products can be used to characterize biomass and carbon storage at the landscape level. This research has demonstrated the adoption of IPCC?s Tier 2, a combination of field and remote sensing data in the assessment of available biomass levels in a tropical forest. The maps created can assist in providing information for biomass and carbon level in MANP for monitoring, reporting and verification in compliance with REDD requirements. Furthermore, this study can provide helpful information regarding policy implications for reforestation and afforestation activities.Item Assessing Available Woody Plant Biomass on Rangelands with Lidar and Multispectral Remote Sensing(2012-07-16) Ku, Nian-WeiThe 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.Item Continuous fermentation of food scraps with constant pH control to produce carboxylic acids(2009-05-15) Coleman Jr., Stanley AlbertGlobal energy demands combined with environmental restrictions are fueling a move to alternative energy sources. Biofuels are formed from biomass; the MixAlco process is one such method. In this work, food scraps are explored as a potential feedstock to the MixAlco process. Batch fermentation with various temperatures, buffers, and pH control methods elucidated the behavior of food scraps during fermentation. The pH and reactor configuration were limiting factors when maximizing production. A fermentor was developed and tested with constant pH control. This resulted in elevated concentration (100 g/L) and selectivity (82%) of desired products. The fermentation resulted in elevated concentrations, but low conversion of solids. The undigested material may serve as a nutrient source for fermenting lignocellulosic feedstocks. Combining various nutrient sources with lignocellulose, such as bagasse, resulted in additional production and further conversion. Multiple nutrient sources were tested resulting in total acid concentration ranging from 20.2 to 34.5 g/L.Item Estimating forest structural characteristics with airborne lidar scanning and a near-real time profiling laser systems(2009-05-15) Zhao, KaiguangLiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatiallyexplicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent and large-scale mapping. At the same time, a growing need is arising for realtime remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real- time forest inventory. The development of such a system involves implementing the on-board data processing and analysis as well as building useful regression-based models to relate LiDAR measurements with forest biophysical parameters. This work established a paradigm for an on-the-fly airborne profiling LiDAR system to inventory regional forest resources in real- or near real- time. The system was developed based on an existing portable airborne laser system (PALS) that has been previously assembled at NASA by Dr. Ross Nelson. Key issues in automating PALS as an on-the-fly system were addressed, including the design of an archetype for the system workflow, the development of efficient and robust algorithms for automatic data processing and analysis, the development of effective regression models to predict forest biophysical parameters from LiDAR measurements, and the implementation of an integrated software package to incorporate all the above development. This work exploited the untouched potential of airborne laser profilers for realtime forest inventory, and therefore, documented an initial step toward developing airborne-laser-based, on-the-fly, real-time, forest inventory systems. Results from this work demonstrated the utility and effectiveness of airborne scanning or profiling laser systems for remotely measuring various forest structural attributes at a range of scales, i.e., from individual tree, plot, stand and up to regional levels. The system not only provides a regional assessment tool, one that can be used to repeatedly, remotely measure hundreds or thousands of square kilometers with little/no analyst interaction or interpretation, but also serves as a paradigm for future efforts in building more advanced airborne laser systems such as real-time laser scanners.Item Feedstock Logistics of a Mobile Pyrolysis System and Assessment of Soil Loss Due to Biomass Removal for Bioenergy Production(2012-10-19) Bumguardner, MarisaThe purpose of this study was to assess feedstock logistics for a mobile pyrolysis system and to quantify the amount of soil loss caused by harvesting agricultural feedstocks for bioenergy production. The analysis of feedstock logistics was conducted using ArcGIS with the Network Analyst extension and model builder. A square grid methodology was used to determine biomass availability of corn stover and bioenergy sorghum in Texas. The SWAT model was used to quantify soil erosion losses in surface runoff caused by sorghum residue removal for bioenergy production in the Oso Creek Watershed in Nueces County. The model simulated the removal of 25, 50, 75, and 100 percent residue removal. The WEPS model was used to quantify wind erosion soil loss caused by corn stover removal in Dallam County. Nine simulations were run estimating soil loss for corn stover removal rates of 0 percent to 50 percent. The results of the SWAT and WEPS analyses were compared to the NRCS tolerable soil loss limit of 5 tons/acre/year for both study areas. The GIS analysis determined the optimum route distances between mobile unit sites were 2.07 to 58.02 km for corn and 1.95 to 60.36 km for sorghum. The optimum routes from the mobile pyrolysis sites and the closest refineries were 49.50 to 187.18 km for corn and 7.00 to 220.11 km for sorghum. These results were used as input to a separate bioenergy economic model. The SWAT analysis found that maximum soil loss (1.24 tons/acre) occurred during the final year of the simulation where 100 percent of the sorghum residue was removed. The WEPS analysis determined that at 30 percent removal the amount of soil loss starts to increase exponentially with increasing residue removal and exceeds the tolerable soil loss limit. Limited harvesting of biomass for bioenergy production will be required to protect crop and soil productivity ensuring a sustainable biomass source.Item Fundamental study of structural features affecting enzymatic hydrolysis of lignocellulosic biomass(Texas A&M University, 2006-10-30) Zhu, LiLignocellulose is a promising and valuable alternative energy source. Native lignocellulosic biomass has limited accessibility to cellulase enzyme due to structural features; therefore, pretreatment is an essential prerequisite to make biomass accessible and reactive by altering its structural features. The effects of substrate concentration, addition of cellobiase, enzyme loading, and structural features on biomass digestibility were explored. The addition of supplemental cellobiase to the enzyme complex greatly increased the initial rate and ultimate extent of biomass hydrolysis by converting the strong inhibitor, cellobiose, to glucose. A low substrate concentration (10 g/L) was employed to prevent end-product inhibition by cellobiose and glucose. The rate and extent of biomass hydrolysis significantly depend on enzyme loading and structural features resulting from pretreatment, thus the hydrolysis and pretreatment processes are intimately coupled because of structural features. Model lignocelluloses with various structural features were hydrolyzed with a variety of cellulase loadings for 1, 6, and 72 h. Glucan, xylan, and total sugar conversions at 1, 6, and 72 h were linearly proportional to the logarithm of cellulase loadings from approximately 10% to 90% conversion, indicating that the simplified HCH-1 model is valid for predicting lignocellulose digestibility. Carbohydrate conversions at a given time versus the natural logarithm of cellulase loadings were plotted to obtain the slopes and intercepts which were correlated to structural features (lignin content, acetyl content, cellulose crystallinity, and carbohydrate content) by both parametric and nonparametric regression models. The predictive ability of the models was evaluated by a variety of biomass (corn stover, bagasse, and rice straw) treated with lime, dilute acid, ammonia fiber explosion (AFEX), and aqueous ammonia. The measured slopes, intercepts, and carbohydrate conversions at 1, 6, and 72 h were compared to the values predicted by the parametric and nonparametric models. The smaller mean square error (MSE) in the parametric models indicates more satisfactorily predictive ability than the nonparametric models. The agreement between the measured and predicted values shows that lignin content, acetyl content, and cellulose crystallinity are key factors that determine biomass digestibility, and that biomass digestibility can be predicted over a wide range of cellulase loadings using the simplified HCH-1 model.Item High-biomass sorghums for biomass biofuel production(2011-05-09) Packer, DanielHigh-biomass sorghums are being developed as a dedicated energy crop for biofuels. Their high biomass yields provide large quantities of structural carbohydrates (cellulose, lignin, etc.) for energy production. Sorghum improvement for applications such as grain or fodder production is well established, but development of high-biomass sorghums for biofuels is not. Thus the objectives of this research were to develop information on sorghum improvement methods and criteria for high-biomass sorghums including marker-assisted selection, use of exotic germplasm, heterosis, and GxE variability of biomass composition. Marker-assisted selection was compared to testcross selection for identifying photoperiod-insensitive (PI) experimental lines that yield photoperiod-sensitive (PS) hybrids within the Ma1/Ma5/Ma6 hybrid production system. High-biomass sorghums are PS and the Ma1/Ma5/Ma6 hybrid production system produces PS hybrids with PI parents by manipulating alleles at the Ma1, Ma5 and Ma6 sorghum maturity loci. Four hundred eighty three sorghum lines were genotyped at the Ma1 and Ma5 loci to predict their hybrid photoperiod reactions and testcrossed to establish their actual hybrid photoperiod reactions. Ma1/Ma5 marker selections for lines producing PI hybrids were reliable and could be used to discard such lines. Ma1/Ma5 marker selections for lines producing PS hybrids were not reliable and identification of such lines will require testcrossing or potentially, genotyping at Ma6 or other additional loci. An attempt was made to determine whether meaningful relationships exist between the passport data (geographic origin) of exotic sorghum accessions and high-biomass desirability. Such a relationship could be used to prioritize exotic sorghum accessions for breeding evaluations. Seventeen hundred ninety two exotic sorghum accessions from 7 different geographic origins were evaluated for high-biomass desirability in 3 environments. Significant relationships between passport data and high-biomass desirability were identified within environments but were not applicable across environments because of large GxE interactions. A larger sampling of environments will be needed to understand and establish reliable passport data and high-biomass desirability GxE patterns. High-parent heterosis can improve yields in high-biomass sorghums and hybrid entries derived from high-biomass sorghum pollinators and grain sorghum females were evaluated for biomass heterosis. Grain sorghum females enable commercial seed production of high-biomass sorghums. Moderate levels of biomass high-parent heterosis were widely available in the hybrids. Heterosis and biomass yields were maximized in specific hybrid combinations and were subject to GxE interactions. Biomass composition (percent cellulose, hemicellulose, etc.) affects the conversion efficiency of biomass to liquid fuels and may be altered via breeding selections. Breeding methods and genotype recommendations for biomass composition will require consideration of GxE variability. The biomass composition of 12 sorghums grown across 5 environments was estimated using Near-Infrared Spectroscopy to identify GxE patterns. Significant GxE interactions for biomass composition were identified, but most compositional variability was attributable to environmental differences. Differences between genotypes for compositional traits were small (1-3 percent), but may prove important with large-scale biomass processing.Item Impact of Herbicides on Winter Canola (Brassica napus L.) Production and Fatty Acid Composition in South Texas(2013-01-16) Cogdill, Todd JosephCanola is a cool-season, oilseed crop grown throughout Europe, Canada, and the Northern Great Plains region of the United States. The expansion of canola production into new growing regions, such as the Southern Plains region, has resulted in new production challenges. The Southern Plains region cultivates canola as a winter annual compared to a spring annual for the Northern Great Plains and Canada. Given the difference in climate and weed spectrum, region-specific weed management systems need to be developed. Agronomic practices can affect seed oil content, protein content, and fatty acid composition, however the effect of herbicides on these and other characteristic of canola are unknown. Therefore, experiments were conducted in 2010 and 2011 to evaluate a broad spectrum of herbicides for potential use in South Texas canola production with respect to crop injury, effects on canola seed oil content, fatty acid composition, weed control, biomass yield, and forage quality. Visual crop injury at 42 DAE was unacceptable for saflufenacil at both 0.12 and 0.06 kg ai ha-1 and ethalfluralin at 1.05 kg ai ha-1. Trifluralin at 1.12 and 0.56 kg ai ha-1, S-metolachlor at 2.14 and 1.07 kg ai ha-1, pyroxasulfone at 0.24 and 0.12 kg ai ha-1, and pendimethalin at 0.8 kg ai ha-1 had lowest visual injury of all treatments. Fluroxypyr applied EPOST caused severe injury at both 0.21 and 0.11 kg ae ha-1. All other EPOST treatments did not cause any visible injury. Seed oil content was not affected by the herbicides evaluated. Fatty acid composition, specifically stearic acid, oleic acid, linolenic acid, and oleic to linolenic acid ratio, was affected by herbicide treatments. This research found that protoporphyrinogen oxidase (PPG oxidase) inhibitor herbicides, such as carfentrazone-ethyl and saflufenacil, negatively affect canola oil quality. Biomass yield was improved for all herbicide treatments except pendimethalin PRE when compared to the untreated plots. Crude protein content of canola forage was not affected by herbicide treatment. Digestible dry matter appeared to be reduced by treatments that included an EPOST application of sethoxydim. The research shows that pendimethalin and S-metolachlor may be suitable for canola production in South Texas based on low crop injury and effective weed control. Neither pendimethalin nor S-metolachlor is currently labeled for use in canola. The herbicides trifluralin, ethalfluralin, quizalofop P-ethyl, ethametsulfuron-methyl, sethoxydim, glyphosate, clethodim, and clopyralid are currently labeled for use in canola and were confirmed suitable for canola production in South Texas. Carfentrazone-ethyl is currently labeled for use in canola but the effects on oil quality should be considered.Item Introduction and Selection of Photoperiod Sensitive Sorghum Genotypes for Agronomic Fitness and Biomass Composition(2012-10-19) Hoffmann, LeoIn 2007, U.S. Congress created the "Energy Independence and Security Act" with primary goals focused on increasing the knowledge in production of renewable fuels, increasing the percentages of renewable fuels in the transportation sector and decreasing the emissions of greenhouse gases from fossil fuel sources. To achieve these goals, many species have been pointed as sources of feedstock for the biofuel industry. Photoperiod sensitive (PS) biomass sorghum for the lignocellusosic based conversion is one. In this study, three main objectives were addressed regarding the relative performance for biomass yield and biomass composition of PS biomass sorghum. First, genetic and environmental variation effects on the biomass yield and biomass composition, and usefulness of pre-classification of genotypes by biomass lignin content were evaluated. On the set of genotypes and locations tested, the environmental effect had the largest influence on the biomass composition, yield and its components. Although smaller, the genetic variation effect was significant for most of the traits, some traits had significant genotype by environment GXE interaction. The pre-classification of genotypes according to lignin content proved to be an efficient system of separating genotypes as groups, but failed to be efficient in separating on the entries bases. Assessment of growth patterns for biomass yield and composition, characterized photoperiod sensitive sorghum as capable of producing a harvestable crop as soon as 4 months, but variations in the concentration of constituents and moisture percentage, pointed to a harvest window that can be extended up to the 7th month after planting. Genetic variation was observed in this trail for most agronomic and composition traits, but a strong environmental effect was also observed. Lastly, the influence of three diverse cytoplasm male sterility (CMS) systems in biomass sorghum hybrids was assessed. The presence of A1, A2 or A3 CMS in the hybrids tested in this study had no influence on the biomass yield performance or in the biomass composition. Therefore, any of the CMS systems can be used in the production of biomass sorghum hybrid seed. Also, in this trial the environmental effects were significant and strong for most traits evaluated.Item Investigation Of Synergistic NOx Reduction From Cofiring And Air Staged Combustion Of Coal And Low Ash Dairy Biomass In A 30 Kilowatt Low NOx Furnace(2013-08-01) Lawrence, Benjamin DanielAlternate, cost effective disposal methods must be developed for reducing phosphorous and nitrogen loading from land application of animal waste. Cofiring coal with animal waste, termed dairy biomass (DB), is the proposed thermo-chemical method to address this concern. DB is evaluated as a cofired fuel with Wyoming Powder River Basin (PRB) sub-bituminous coal in a small-scale 29 kW_(t) low NO_(x) burner (LNB) facility. Fuel properties, of PRB and DB revealed the following: a higher heating value of 29590 kJ/kg for dry ash free (DAF) coal and 21450 kJ/kg for DAF DB. A new method called Respiratory Quotient (RQ), defined as ratio of carbon dioxide moles to oxygen moles consumed in combustion, used widely in biology, was recently introduced to engineering literature to rank global warming potential (GWP) of fuels. A higher RQ means higher CO_(2) emission and higher GWP. PRB had an RQ of 0.90 and DB had an RQ of 0.92. For comparison purposes, methane has an RQ of 0.50. For unknown fuel composition, gas analyses can be adapted to estimate RQ values. The LNB was modified and cofiring experiments were performed at various equivalence ratios (phi) with pure coal and blends of PRB-DB. Standard emissions from solid fuel combustion were measured; then NO_(x) on a heat basis (g/GJ), fuel burnt fraction, and fuel nitrogen conversion percentage were estimated. The gas analyses yielded burnt fraction ranging from 89% to 100% and confirmed an RQ of 0.90 to 0.94, which is almost the same as the RQ based on fuel composition. At the 0.90 equivalence ratio, unstaged pure coal produced 653 ppm (377 g/GJ) of NOx. At the same equivalence ratio, a 90-10 PRB:LADB blended fuel produced 687 ppm (397 g/GJ) of NO_(x). By staging 20% of the total combustion air as tertiary air (which raised the equivalence ratio of the main burner to 1.12), NO_(x) was reduced to 545 ppm (304 g/GJ) for the 90-10 blended fuel. Analysis of variance showed that variances were statistically significant because of real differences between the independent variables (equivalence ratio, percent LADB in the fuel, and staging intensity).Item Landowner perception, awareness, and adoption of wildfire programs in the Southern United States(2009-05-15) Jarrett, Adam R.Non-industrial Private Forests (NIPF) landowners constitute a major component of the forested land portfolio in the Southeastern United States. The lands they possess provide a variety of social benefits but many aspects of how these landowners manage their properties exist. The goal of this research was to determine overall landowner awareness regarding wildfire programs and education and identify interrelationships among management strategies, demographic variables, and experiences. Specifically, it was hypothesized that landowner program awareness, interest in biomass utilization, and wildfire mitigation strategies would be influenced by the type of information they received, management activities, and other factors. Seven logit models were constructed to analyze these interrelationships. Results revealed that the type and quality of information landowners received was important in most cases. Landowners not receiving any information were less likely to take action to prevent or mitigate wildfire damage to their property. Wildfire education was highly valued by participants. Knowledge of existing biomass utilization programs was almost non-existent. However, the desire to obtain information on this topic was high. In general, state agencies were utilized more than federal agencies, and landowners felt that cost-share programs and marketability of removed biomass would encourage participation in wildfire prevention activities.Item Liquid-phase Processing of Fast Pyrolysis Bio-oil using Pt/HZSM-5 Catalyst(2013-05-01) Santos, Bjorn SanchezRecent developments in converting biomass to bio-chemicals and liquid fuels provide a promising sight to an emerging biofuels industry. Biomass can be converted to energy via thermochemical and biochemical pathways. Thermal degradation processes include liquefaction, gasification, and pyrolysis. Among these biomass technologies, pyrolysis (i.e. a thermochemical conversion process of any organic material in the absence of oxygen) has gained more attention because of its simplicity in design, construction and operation. This research study focuses on comparative assessment of two types of pyrolysis processes and catalytic upgrading of bio-oil for production of transportation fuel intermediates. Slow and fast pyrolysis processes were compared for their respective product yields and properties. Slow pyrolysis bio-oil displayed fossil fuel-like properties, although low yields limit the process making it uneconomically feasible. Fast pyrolysis, on the other hand, show high yields but produces relatively less quality bio-oil. Catalytic transformation of the high-boiling fraction (HBF) of the crude bio-oil from fast pyrolysis was therefore evaluated by performing liquid-phase reactions at moderate temperatures using Pt/HZSM-5 catalyst. High yields of upgraded bio-oils along with improved heating values and reduced oxygen contents were obtained at a reaction temperature of 200?C and ethanol/HBF ratio of 3:1. Better quality, however, was observed at 240 ?C even though reaction temperature has no significant effect on coke deposition. The addition of ethanol in the feed has greatly attenuated coke deposition in the catalyst. Major reactions observed are esterification, catalytic cracking, and reforming. Overall mass and energy balances in the conversion of energy sorghum biomass to produce a liquid fuel intermediate obtained sixteen percent (16 wt.%) of the biomass ending up as liquid fuel intermediate, while containing 26% of its initial energy.Item Marker-Assisted Verification of Hybrids in Pearl Millet-Napiergrass (Pennisetum glaucum [L.] R. Br. x Pennisetum purpureum Schumach.)(2012-02-14) Dowling, CharlieMarker-Assisted Verification of Hybrids in Pearl Millet-Napiergrass (Pennisetum glaucum [L.] R. Br. x Pennisetum purpureum Schumach.). (December 2011) Charlie D. Dowling, III, B.S., College of Agriculture and Life Sciences Chair of Advisory Committee: Dr. Russell W. Jessup A high-biomass perennial grass that is directly seeded using existing farm equipment can reduce both planting and overall input costs. Three cytoplasmic male-sterile cms A-lines and four fertile genotypes of pearl millet (Pennisetum glaucum [L.] R. Br.) and one novel pearl millet selection from the Perennial Grass Breeding Program at Texas A&M University were selected to cross with napiergrass (Pennisetum purpureum Schumach.). The pearl millet parents were chosen based on characteristics such as basal tillering, plant height, and days to anthesis. Three napiergrass accessions from the Perennial Grass Breeding Program and the cultivar Merkeron were used as pollinators for these crosses. The cms and fertile pearl millet accessions produced full heads of seed when pollinated with napiergrass. There were a large range of seed sizes and weights for each hybrid family, and the seed were separated into four size classes. The weight differences from the largest to smallest class of seed varied by more than 30%. All of the seed classes germinated, and seed size, in this case, was completely unrelated to the ability to germinate. 100% germination was observed in five seed size classes for both PMN iv hybrids, and 90% germination was observed in three of the eight classes. Essentially all of the hybrid seed recovered from the original pearl millet x napiergrass crosses germinated, but all of the F 1 hybrids were sterile in that none of them produced viable seed. Flow cytometry could not be used to identify the hybrids because the DNA content of pearl millet and napiergrass were essentially the same even though distinct 2C and 4C peaks were seen from the diploid pearl millet. From the 58 EST-SSRs surveyed in the bulked segregate analysis, several were heterozygous dominant and many were homozygous dominant and hemizygous at its particular loci. Seven hemizygous EST-SSRs were identified for Merkeron, seven for PEPU09FL01, eight for PEPU09FL02, and six for PEPU09FL03. These markers are extremely valuable to any pearl millet x napiergrass hybridization program because they provide a means whereby the hybrids can be easily identified. Identification of hemizygous pearl millet markers will also assist in future DNA sequencing and also in a marker-assisted breeding program.Item Mercury emission control for coal fired power plants using coal and biomass(2009-05-15) Arcot Vijayasarathy, UdayasarathyMercury is a leading concern among the air toxic metals addressed in the 1990 Clean Air Act Amendments (CAAA) because of its volatility, persistence, and bioaccumulation as methylmercury in the environment and its neurological health impacts. The Environmental Protection Agency (EPA) reports for 2001 shows that total mercury emissions from all sources in USA is about 145 tons per annum, of which coal fired power plants contribute around 33% of it, about 48 tons per annum. Unlike other trace metals that are emitted in particulate form, mercury is released in vapor phase in elemental (Hg0) or oxidized (Hg2+, mainly HgCl2) form. To date, there is no post combustion treatment which can effectively capture elemental mercury vapor, but the oxidized form of mercury can be captured in traditional emission control devices such as wet flue gas defulrization (WFGD) units, since oxidized mercury (HgCl2) is soluble in water. The chlorine concentration present during coal combustion plays a major role in mercury oxidation, which is evident from the fact that plants burning coal having high chlorine content have less elemental mercury emissions. A novel method of co-firing blends of low chlorine content coal with high chlorine content cattle manure/biomass was used in order to study its effect on mercury oxidation. For Texas Lignite and Wyoming coal the concentrations of chlorine are 139 ppm and 309 ppm on dry ash free basis, while for Low Ash Partially Composted Dairy Biomass it is 2,691 ppm. Co-firing experiments were performed in a 100,000 BTU/hr (29.3 kWt) Boiler Burner facility located in the Coal and Biomass Energy laboratory (CBEL); coal and biomass blends in proportions of 80:20, 90:10, 95:5 and 100:0 were investigated as fuels. The percentage reduction of Hg with 95:5, 90:10 and 80:20 blends were measured to be 28- 50%, 42-62% and 71-75% respectively. Though cattle biomass serves as an additive to coal, to increase the chlorine concentration, it leads to higher ash loading. Low Ash and High Ash Partially Composted Dairy Biomass have 164% and 962% more ash than Wyoming coal respectively. As the fraction of cattle biomass in blend increases in proportion, ash loading problems increase simultaneously. An optimum blend ratio is arrived and suggested as 90:10 blend with good reduction in mercury emissions without any compromise on ash loading.Item Modeling of the reburn process with the use of feedlot biomass as a reburn fuel(2009-05-15) Colmegna, GiacomoCoal fired power plants will face many challenges in the near future as new regulations, such as the Clear Sky Act, are being implemented. These regulations impose much stricter limits on NOx emissions and plan to impose limits on mercury emissions from coal fired boilers. At this time no technologies are currently being implemented for control of Hg and this explains the strong interest in this area by the Department of Energy (DOE). Reburn technology is a very promising technology to reduce NOx emissions. Previous experimental research at TAMU reported that Feedlot Biomass (FB) can be a very effective reburn fuel, for reduction of NOx up to 90%-95%; however, little work has been done to model such a process with Feedlot Biomass as reburn fuel. The present work addresses the development of a reburn model to predict NOx and Hg emissions. The model accounts for finite rate of heating of solid fuel particles, mixing with NOx laden hot gases, size distribution, finite gas phase and heterogeneous chemistry, and oxidation and reduction reactions for NOx and Hg. To reduce the computational effort all the reactions, except those involved in mercury oxidation, are modeled using global reactions. Once the model was validated by comparison with experimental findings, extensive parametric studies were performed to evaluate the parameters controlling NOx reduction. From DOE research programs some experimental data regarding the capture of mercury from power plant is available, but currently no experimental data are available for Hg emission with reburn process. This model has shown a very large mercury reduction using biomass as a reburn fuel. The model recommends the following correlations for optimum reduction of NOx: Equivalence Ratio should be above 1.05; mixing time should be below 100ms (especially for biomass); pure air can be used as the carrier gas; the thermal power fraction of the reburner should be between 15% and 25%; residence time should be at least 0.5s and the Surface Mean Diameter (SMD) of the size distribution should be as small as possible, at least below 100 ?m.Item Non-Reacting Flow Characteristics and Emissions Reduction on Blends of Coal and Dairy Biomass in 30 kW_(t) Low NO_(x) Down-Fired Furnace(2014-08-07) Tiyawongsakul, TiyawutRecently, coal-fired power plants have considered either to retire themselves or to use natural gas as the main energy source instead of coal due to more stringent air pollution regulations for nitrogen oxides (NO_(x)), mercury (Hg) and more recently the required CO_(2) reduction of 30% by 2030. Clean coal technology must be continuously developed in order to prevent people from losing their jobs and to decrease the negative impacts of firing coal on environment. The present research focuses on NO_(x) emissions which arise mainly due to oxidation of fuel-bound nitrogen using low NO_(x) burner (LNB) when fired with Wyoming Powder River Basin coal (PRB) and blends of coal and dairy biomass (DB). The DB was selected as co-fired fuel for possible elimination of DB from dairy feedlots which result in land, air and water pollution if not properly disposed of. LNB adopts staged air introduction in order to limit the availability of oxygen when nitrogen from fuel is released. To achieve the objective, the mixing patterns between fuel particle and air were predicted using non-reacting flow (NRF) simulation inside the cylindrical combustion chamber. The effects of varying burner parameters, fuel particle sizes, main burner equivalence ratios (ER_(mb)) and overall equivalence ratios (ER_(oa)) on mixing characteristics were investigated. Then, the LNB components were modified based on the results from NRF simulation. The modified main burner is a partially premixed swirl burner (fuel mixes with the primary air inside the fuel/primary air nozzle, and the secondary air is swirled by the straight-vane swirler) whose swirl angle and secondary air swirl number are 59? and 1.42 respectively. The circular over-fire air (OFA) nozzles are located 484 mm below the main burner exit, and the OFA is injected into the combustion chamber in the radial direction. The fuels used in the research were: 1) pure PRB and 2) the fuel blend of PRB and DB with the PRB-to-DB ratio of 90 to 10 on mass basis (90-10 PRB-DB blend). Fuel characteristics were first obtained, and empirical chemical formulae were deduced. The CO_(2), O_(2) and NO were measured as a function of ER_(oa) and ER_(mb) (ER_(mb) based on air flow without inclusion of OFA). The gas analyses were used to obtain the burnt fraction, respiratory quotient (RQ, = CO_(2) moles produced/O_(2) moles consumed) and equivalence ratio which is then checked against measured values. Uncertainty analyses were also performed. The optimum conditions for minimum NO_(x) emission that pass the EPA limit (210 g/GJ) were obtained as follows. With ER_(oa) = 0.95, firing pure PRB produced NO_(x) 220 g/GJ without OFA, and 179 g/GJ with OFA (ER_(mb) = 1.10) which is about 18.6 % reduction. Under same conditions, the co-firing of 90-10 PRB-DB blend decreased NO_(x) by 3.6% without OFA, and 22.2% with OFA (ER_(mb) = 1.10) compared to firing pure PRB at ER_(oa) = 0.95 without OFA. Furthermore, co-firing 90-10 PRB-DB blend with OFA at ER_(mb) = 1.10 and ER_(oa) = 0.95 (excess air 5.26%) emitted NO_(x) approximately 171 g/GJ whilst firing pure PRB without OFA at ER_(oa) = 0.85 (excess air 17.65%) emitted NO_(x) approximately 330 g/GJ which is 48% reduction and less than 210 g/GJ (the current EPA limit). This reduction could benefit 500-MWt power plants approximately $113,500 per year in case the efficiency of power plants is 35% and NO_(x) are traded at $15.89 per short ton.Item Recovery of Carboxylic Acids from Fermentation Broth via Acid Springing(2010-01-14) Dong, JipengA proprietary technology owned by Texas A