The potential of oleaginous yeast Rhodotorula glutinis for the sustainable production of biodiesel feedstock via fermentation of lignocellulosic biomass in pulp and paper wastewater as a fermentation media was investigated. The overall objective was to increase the levels of lipid feedstock in oleaginous yeast in order to reduce biodiesel production cost. To meet sustainable production of biodiesel, industrial wastewater and waste lignocellulose biomass were used as cultivation media and carbon source, respectively. Pulp and paper wastewater effluent was selected as a source of water and nutrients for the production of microbial lipids due to its environmental pollution as it creates large volume of wastewater discharge with high chemical oxygen demand (COD). Since medium composition and process fermentation condition can significantly affect the fermentative performance of oleaginous microorganisms, to find the optimum cultivation condition, design of experiment combined with RSM optimization technique was performed, which has been shown to be successful to predict the optimum condition for the biomass and lipid production in batch fermentation. In addition, lignocellulosic biomass hydrolysate was used as a substrate to improve the cost associated with feedstock fermentation. Lignocellulosic hydrolysate, a product of degradation of lignocelllosic biomass, contains degradation by-products such as 5- hydroxymethylfurfural (HMF), furfural and acetic acid that are known as major inhibitors that influences microorganism growth process. Therefore, their impacts on the fermentative performance and lipid productivity of oleaginous yeast were explored. A detailed operating condition and equipment design for the process of biocrude production from pulp and paper wastewater on a commercial scale was developed. A technological assessment of the process was performed to evaluate their technical benefits and limitations. Results show that pulp and paper wastewater can be used as a cultivation media for the production of microbial lipids using R. glutinis. However, its carbon content has to be improved. Analysis of the design and cost of the process showed that acid hydrolysis process using paper mill sludge as lignocellulosic biomass required the smallest process equipment units but at a higher raw material cost compared to fermentation process.

Thesis submitted in partial fulfillment for the Degree of Master of Technology: Chemical Engineering, Durban University of Technology, 2010. / THE OBJECTIVE of this study was to devise a purification process, using ultrafiltration membranes as the core technology, for the preparation of corn steep liquor (CSL) as a fermentation feedstock. This process inherently required the development of a pretreatment system for the ultrafiltration membranes for the removal of suspended solids and high fouling material from corn steep liquor. The ultrafiltration membrane system was required for the separation and removal of colloidal solids from corn steep liquor, and to fractionate and separate out unwanted proteins, to render the feedstock suitable for sterilisation and subsequent fermentation. THE CONCEPT of membrane technology was investigated in order to find a more practical alternative for what was deemed to be a difficult process problem. In particular, various pretreatment technologies were investigated to form a compact and robust process package. THE CORN STEEP LIQUOR, a by-product of the corn wet milling process, was obtained from African Products, Germiston, in the form of a concentrated slurry directly from an evaporator system. A diagnostic of the feedstock was carried out and from this information, it was decided that three pretreatment options would be investigated. The first option was the pH treatment of the corn liquor, by the addition of ammonia which induced the precipitation of solids. This was followed by liquid-solid separation, and the clarified liquor was fed to the membrane system. The second option looked at the separation of suspended solids from the liquor by the use of broth conditioning additives and separation of the solids by a decanter centrifuge. The third option investigated was the use of a gyratory screening system for the removal of all solids greater than 100 μ in size. IN THE pH TREATMENT of CSL, the process is effected by the addition of base to pH 7. The technology involves neutralisation of CSL in a mixing system, under predetermined conditions of temperature, agitation and rate of addition, followed by subsequent liquid-solid separation. Trials were conducted on a pilot plant to test the process. Initial trials, conducted on a small scale pilot filter press, proved to be successful for this application. A suspended solids removal of up to 98% was achieved. The average suspended solids in the filtrate was found to range between 0.1 to 0.25 %. Tests were also conducted on a hired “state of art” filtration plant under various conditions. A diaphragm membrane press was found to provide the best performance. Protein recoveries of above 95 % at fluxes of 35 L/m2h at temperatures above 50 °C, and an incremental application of feed pressure was most suited for the process. The removal of the colloidal solids by the above-mentioned process was found to improve the quality of sterilisation. A reduction of more than 90 % in coagulated solids was achieved. v i IT WAS OBSERVED that the separation of suspended solids from CSL is enhanced by the use of coagulation and flocculation. Although not commonly used for this purpose, it was felt that a decanter centrifuge was well suited for the subsequent separation of the flocs from the clarified liquor. This work describes the results of the trials with such a device and the impact of broth conditioning on the efficiency of the separation. Trials have been conducted using an Alfa-Laval Model NX210 decanter, which was not specifically built for the work and therefore imposed several limitations on its performance. Despite these shortcomings, preliminary trials proved to be successful in achieving the separation objective. Tests were conducted using five different batches of CSL. With a maximum suspended solids loading of 4.3 % and a feed rate of 700 L/h, a solids recovery of 90 % was achieved. The clarified liquor contained residual solids between 0.5 and 0.8 %. The sludge had a solids concentration that ranged between 43 % and 65 %. COAGULATION AND FLOCCULATION dosages were kept within the limits of the laboratory evaluations. Flocculant dosages were controlled between 100 and 200 ppm, with the coagulant operating at higher dosages of between 400 and 2000 ppm. The only controllable parameter on the machine itself was the scroll differential speed. The best performance in terms of the cake dryness and centrate clarity was obtained at the lowest scroll differential speed of 4 rpm. THE USE OF GYRATORY SCREENS entailed passing the raw liquor through a set of two screens. The technology involves the use of a gyratory mechanism, which aids in the cleaning of the screens during continuous operation. Trials have been conducted on a pilot plant to test the system. Since the unit used was designed specifically for quick on-site screening exercises, it did not possess the added flexibility and robustness of a properly designed full scale unit. This imposed some limitations on its performance. However, despite these shortcomings, the trials conducted on the pilot plant proved to be successful in meeting the outlined objectives. A NUMBER OF TRIALS were performed on various batches of CSL. There was considerable batch to batch variation in the suspended solids content of the CSL and this was found to ultimately affect the throughput of the screening process. The feed suspended solids varied between 10 and 18 %. The highest throughput achieved was 400 L/h at a feed suspended solids loading of 14.5 %. It was found that temperature made a significant impact on the separation. The loss of heat in the feed stream caused excessive coagulation to occur thus increasing the suspended solids loading and lowering the throughput. The total solids in the sludge stream varied between 45 and 77 %. Protein loss in the sludge stream was around 1 %. Careful attention had to be given to the handling of the sludge stream. This stream displayed rheological characteristics typical of a non-Newtonian thixotropic fluid. The 100 μm screen operated best vi i when prior separation was done using a 180 to 200 μm screen. This reduced the solids loading on the tighter screen and increased the throughput by 10 to 15 %. The self cleaning mechanism also performed more efficiently under these conditions. THE SELECTED OPTION was then based on the influence the operation had on the ultrafiltration membranes, sterilisation of the product prior to fermentation and ultimately the fermentation performance. Subsequent testing of the pretreatment options were performed on an ultrafiltration membrane test cell. The product from the gyratory screens were found to produce the best overall results, where the highest fluxes and least amount of fouling occurred on the membranes tested. ONCE THE PRETREATMENT OPTION was decided, the development of the membane ultrafiltration system was then pursued. Trials were conducted on a laboratory scale, in a membrane test cell, to determine the preliminary screening of the membrane type, fouling effects and fluxes. It was found that polyvinylidene and polyacrylonitrile membranes produced the best overall fluxes of 11.25 and 10.96 L/m2h respectively. These membranes produced permeate protein concentrations of 121 and 115 g/L respectively. Sterilisation tests conducted on the permeate streams produced also showed that these two membranes had the lowest suspended solids concentrations. FERMENTABILITY tests conducted, showed that the ultrafiltered CSL, from these two membranes, produced increased cell counts and protein utilisation along with an increased product yield. Approximately 42 g/L of biomass was generated with lysine yields of 46 g/L. Further testwork revealed the non-Newtonian nature of CSL and its inherent viscosity effects. BENCH-SCALE testwork was conducted for various membrane configurations. With tubular membranes and hollow fibre membranes, average fluxes of 6.23 and 4.5 L/m2h were achieved respectively. Spiral wound membranes were found to be more consistent in their performance, with average fluxes of around 6.25 L/m2h. For the spiral wound membranes, it was found that the Desal-2 mesh spacer with a 80 mil thickness was most appropriate for the duty. PILOT PLANT testwork was conducted to scale-up the membrane system and to eliminate possible risks associated with the technology. The pilot plant studies showed up a number of principle design variables which needed careful attention. The flaws in the piloting system were subsequently rectified and this helped to improve the overall performance of the system.

Master of Agribusiness / Department of Agricultural Economics / Jason Bergtold / Markets for alternative fuels are emerging and are of great interest to both public and private companies, as well as government agencies looking to differentiate fuel sources to achieve improved and sustainable operational efficiencies. This creates a growing need for innovation and an increased supply of biofuel feedstocks for bioenergy options such as bio-jet fuel. This thesis aims to assess the logistical feasibility of producing oilseed bio feedstocks and the practicality of building new crush facilities specifically for bio-jet fuel production in Kansas. A logistical optimization model is built by applying data to estimate the potential Kansas supply of rapeseed as a possible feedstock option; transportation and facility costs associated with building; and proposed crushing facility sites, by considering the estimated demand for bio-jet fuel within Kansas. The developed optimization model determined that even average yields per acre and modest adoption rates by farmers willing to incorporate rapeseed into their crop rotations could provide enough feedstock to supply one or two crushing facilities, depending on a variety of additional factors, including bio-jet fuel demand in Kansas. Sensitivity analysis was performed on key model factors and determined that the most influential factor on both size and number of proposed crushing facilities was the market demand for bio-jet fuel. Ultimately, further research is required to better understand the actual market demand for bio-jet fuel within Kansas and how competition or supply supplementation of other bio feedstocks can affect the size or number of proposed crushing facilities. There are currently six oilseed crushing facilities operating in Kansas; although all are dedicated to soybean or sunflower seed. Further studies may find these sites as viable alternative options to building new crushing facilities for a separate type of feedstock.

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

Thesis (M.S.)--Ohio University, August, 2000. / Title from PDF t.p.

This work posits Layered Assembly as a novel, additive manufacturing method which usesvoxels as feedstock to fabricate multi-material objects at order-of-magnitude faster build rates than established additive manufacturing methods. Instead of using resins, filaments, and powders as raw materials, Layered Assembly uses premanufactured bits of matter called voxels, to fabricate truly multi-material, multi-functional parts. The implementation of Layered Assembly in this work is carried out by parallel electrostatic grippers. Electrostatic grippers are chosen as the gripping mechanism as they are solid-state, material-agnostic, adept at grasping millimeter-scale parts, and parallelize well to enable scalable high deposition rates. Most importantly, electrostatic grippers can apply localized electrostatic fields which results in highly selective grasping capability at the millimeter and sub-millimeter scale. The parallel gripping capabilities of electrostatic grippers were characterized for gripping repeatability, and then demonstrated by the fabrication of increasingly complex multi-material parts. Fabricated parts include a letter “C” comprised of 8 voxels, an 18 voxel pyramids and two parts comprised of tens of thousands of voxels. Experiments determined a > 95% gripping reliability independent of array size. The experiments in work have shown parallel electrostatic grippers to be a promising method for both material deposition and parallel pick-and-place manipulation.

Master of Science / Department of Agronomy / Scott A. Staggenborg / Current demand for ethanol production is stressing feedstock production. Previous research has shown sweet sorghum and photoperiod sensitive sorghum [Sorghum bicolor (L.) Moench] as viable feedstocks which may supplement or replace current feedstocks. Studies were conducted at two dryland locations in north central and northeast Kansas in 2008 and 2009 to determine the effects of cultivar, nitrogen fertilizer rate, plant density, and harvest date on sweet sorghum juice and biomass yields. The cultivar study indicated the cultivar ‘M81E’ generally had the greatest yield. Other cultivars were not well suited for this region. No significant results were found in the nitrogen rate trial, indicating sweet sorghum may be insensitive to nitrogen fertilizer applications. The plant density trial results indicated that sweet sorghum possess a great ability to compensate for plant spacing. No differences were found in juice yields across densities, and the only difference found in total dry biomass was at the highest plant density. Results from the harvest date study indicate that sweet sorghum harvest should be delayed until at least the grain soft dough stage and can be continued for at least 10 days after a killing freeze without a yield penalty. Delaying harvest allowed for an increase in total dry matter and fermentable carbohydrates without a decrease in juice yield. Two studies were conducted at two dryland locations in northcentral and northeast Kansas in 2008 and 2009 to determine the effects of plant density on photoperiod sensitive sorghum yields, with an additional study to determine the effects of winter weathering. Photoperiod sensitive sorghum was found to be similarly insensitive to plant density, with few differences found in total dry biomass yield. Yields were found to decrease significantly due to winter weathering. A final study was conducted to examine a variety of sorghums as biofuel feedstocks. Photoperiod sensitive sorghum yielded the greatest in 2008 while sweet sorghum yielded less. In 2009, sweet and photoperiod sensitive sorghum yielded less than the cultivar TAMUXH08001. Sweet sorghum yields are generally the greatest with ‘M81E’ and when harvested after soft dough. Yields of both sorghums are occasionally influenced by plant density.

Sweet sorghum (Sorghum bicolor) has potential as a bioenergy feedstock due to its high yield potential and the production of simple sugars for fermentation. Sweet sorghum cultivars are typically tall, high biomass types with juicy stalks and high sugar concentration. These sorghums can be harvested, milled, and fermented to ethanol using technology similar to that used to process sugarcane. Sweet sorghum has advantages in that it can be planted by seed with traditional planters, is an annual plant that quickly produces a crop and fits well in crop rotations, and it is a very water-use efficient crop. Processing sweet sorghum is capital intensive, but it could fit into areas where sugarcane is already produced. Sweet sorghum could be timed to harvest and supply the sugar mill during the off season when sugarcane is not being processed, be fit into crop rotations, or used in water limiting environments. In these ways, sweet sorghum could be used to produce ethanol in the Southern U.S and other tropical and subtropical environments. Traditionally, sweet sorghum has been grown as a pureline cultivar. However, these cultivars produce low quantities of seed and are often too tall for efficient mechanical harvest. Sweet sorghum hybrids that use grain-type seed parents with high sugar concentrations are one way to overcome limitation to seed supply and to capture the benefits of heterosis. There are four objectives of this research. First to evaluate the importance of genotype, environment, and genotype-by-environment interaction effects on the sweet sorghum yield and composition. The second objective is to determine the presence and magnitude of heterosis effects for traits related to sugar production in sweet sorghum. Next: to study the ability of sweet sorghum hybrids and cultivars to produce a ratoon crop and determine the contribution of ratoon crops to total sugar yield. The final objective is to evaluate variation in composition of sweet sorghum juice and biomass. Sweet sorghum hybrids, grain-type sweet seed parents, and traditional cultivars that served as male parents were evaluated in multi-environment trials in Weslaco, College Station, and Halfway, Texas in 2007 and 2008. Both genotype and environment influenced performance, but environment had a greater effect than genotype on the composition of sweet sorghum juice and biomass yield. In comparing performance, elite hybrids produced fresh biomass and sugar yields similar to the traditional cultivars while overcoming the seed production limitations. High parent heterosis was expressed among the experimental hybrids for biomass yield, sugar yield and sugar concentration. Additional selection for combining ability would further enhance yields and heterosis in the same hybrid. Little variation was observed among hybrids for juice and biomass composition suggesting that breeding efforts should focus on yield before altering plant composition.

>Magister Scientiae - MSc / In South Africa coal combustion constitutes up to 90 % of the country’s energy need. This coal combustion activity is known to contribute to the amount of about 40 % of the total CO2 atmospheric emissions worldwide that are responsible for global warming effects. In addition burning of coal generates a large quantity of fly ash which creates environmental pollution since only a small portion of it is currently used in some applications. In order, on one hand to mitigate and sequester CO2 and on the other hand to reprocess fly ash and reuse it, this study focuses on developing new technologies with cost-effective and less energy consumption in the domain of CO2 capture and sequestration. CO2 has priority attention for being the largest contributor to global warming. Various techniques have been used for CO2 capture and sequestration, such as aqueous alkylamine absorption or adsorption onto a solid adsorbent such as zeolites. In this study NaA zeolite adsorbent was hydrothermally synthesised from South African fly ash. This fly ash based NaA zeolite was then used as starting material to prepare LiA, CaA, and MgA zeolite catalysts via ion-exchange for comparative CO2 adsorption capacity. A systematic design of the ion-exchange procedure was undertaken at either 30 °C or 60 °C for a contact time of 1 hr, 4 hrs, and 8 hrs with 1, 2 and 3 consecutive exchanges in each case in order to determine the optimum conditions for loading each cation exchanged. The adsorption of CO2 on the ion- exchanged fly ash based zeolite-A catalysts was carried out at 40 °C similar to the temperature of flue gas since the catalysts obtained in this study were also prepared with a view to their applications in flue gas system. The CO2 desorption temperature ranged between 40-700 °C. All materials used in this study, starting from fly ash feedstock, werecharacterized using various techniques to monitor the mineral and structural composition, the morphology, surface area and elemental composition and the adsorption capacity. The techniques included mainly Fourier transform infra-red, X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy, Energy dispersive spectroscopy, X-ray fluorescence, Temperature programmed desorption.The results obtained from both Fourier transform infra-red and the X-raydiffraction spectroscopy for samples exchanged at either 30° C or 60 °C showedlower crystallinity in CaA and MgA zeolite samples. This decrease in crystallinitymainly affected the D4R (0-20° 2) and was demonstrated in the study to beinversely proportional to the increase of the atomic radius of cations (Li+ > Mg2+ >Ca2+). In the Fourier transform infra-red, the vibration band at 677 cm-1 attributedto the extra-framework cation, also proportionally increased with the decrease ofthe atomic radius or size of the cations, and was intense in LiA zeolite samples.

Hydrocracking of plastic wastes offers the best value in terms of quality of its process oil product among other feedstock recycling methods capable of recycling mixed plastic waste; a paraffin-rich synthetic crude similar in composition to gasoline and diesel is produced. Additional benefits of the process include heteroatom removal, catalyst conservation as well as a lower process temperature. However PVC content in mixed plastics waste and the high viscosity of plastics are prominent issues in relation to subjecting plastics to petrochemical processes such as hydrocracking. A 5ppm chlorine limit and maximum feedstock viscosity of 0.5 Pas at 200oC is tolerable in the petrochemical industry. Although dechlorination of mixed plastic waste has been studied exhaustively, viscosity studies in relation to process improvement or efficiency in the pyrolysis or hydrocracking of plastics haven’t received as much attention. Viscosity has been identified as being inhibitive to heat and mass transfer, and transport into reactors, as well as being a major problem in relation to designing reactors for feedstock recycling. In this research, four of the main polymer types; high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), Polypropylene (PP), Polystyrene (PS) and Polyethylene Terephthalate (PET) were rheological characterised to establish the extent to which they exceed the recommended viscosity in the petroleum industry. Viscosities 400 – 1200 times the feedstock viscosity in the petrochemical industry at a shear rate of 500s-1, which is typical for pumping and atomisation operations, were obtained during the characterisation of the plastic samples in a conventional capillary rheometer. Saturated chain hydrocarbon solvents (iso-octane, decane, tetradecane, pentadecane and hexadecane) were investigated for treating HDPE, in a range of HDPE-solvent mixtures, in order to reduce its viscosity. Preliminary results of differential scanning calorimetry tests carried out on the solvent-treated HDPE revealed a 12 – 16% drop in the melting peak temperature of the pure HDPE (129 oC) using tetradecane (108 oC), pentadecane (110 oC) and hexadecane (113 oC) for the 20:80 PE-solvent mixtures. iso-octane and decane however only produced a viscosity drop of 3% and 4% respectively for the same 20:80 PE-solvent mixtures. Thermal stability of HDPE was largely unaffected by the solvent treatment except in the case of pentadecane which showed a reducing trend on the decomposition onset temperature as solvent concentration in the starting mixtures was increased, albeit marginal (from 441oC to 437oC). A custom built sealed-vessel impeller viscometer designed to facilitate the treatment of the HDPE via solvent refluxing and in situ viscosity measurement was calibrated by determining constants which enable the conversion of machine data to viscosity and shear rate using Newtonian and non-Newtonian calibration fluids. These constants, the shape factor and shear rate conversion factor, were determined to be 81.03 and 22.08, respectively, with corresponding 95% confidence limits of 79.21 and 86.26, and 21.47 and 24.00. Viscosity measurements of a 40:60 PE-nC15 mixture carried out in the sealed-vessel impeller viscometer at a shear rate of between 71s-1 and 80s-1 at 95% confidence level and 250oC was 7 Pas representing approximately 200 fold reduction from the virgin HDPE measured in the conventional capillary rheometer.