Ultrasonic vibration - assisted pelleting and dilute acid pretreatment of cellulosic biomass for biofuel manufacturing

Doctor of PhilosophyDepartment of Industrial & Manufacturing Systems EngineeringZhijian PeiDonghai WangIn the U.S. and many other countries, the transportation sector is almost entirely dependent on petroleum-based fuels. In 2011, half of the petroleum used in the U.S. was imported. The dependence on foreign petroleum is a real threat to national energy security. Furthermore, the transportation sector is responsible for about 30% of U.S. greenhouse gas emissions and is growing faster than any other major economic sector. National energy security, economy, environment sustainability are all driving the U.S. to develop alternative liquid transportation fuels that are domestically produced and environmentally friendly. Promoting biofuel is one of the efforts to reduce the use of petroleum-based fuels in the transportation sector. Cellulosic biomass are abundant and diverse. Thus, the ability to produce biofuel from cellulosic biomass will be a key to making ethanol competitive with petroleum-based fuels. Ultrasonic vibration- assisted (UV-A) pelleting can increase not only the density of cellulosic biomass but also the sugar yield. This PhD dissertation consists of fourteen chapters. Firstly, an introduction of the research is given in Chapter 1. Chapters 2, 3, 4, and 5 present experimental investigations on effects of input variables in UV-A pelleting on pellet quality. Chapter 6 investigates effects of input variables on energy consumption in UV-A pelleting. Chapter 7 develops a predictive model for energy consumption in UV-A pelleting using the response surface method. Chapter 8 investigates effects of input variables on energy consumption, water usage, sugar yield, and pretreatment energy efficiency in dilute acid pretreatment. Chapter 9 develops a predictive model for energy consumption in dilute acid pretreatment using the response surface method. Chapter 10 studies ultrasonic vibration-assisted (UV-A) dilute acid pretreatment of poplar wood for biofuel manufacturing. Chapter 11 compares sugar yields in terms of total sugar yield and enzymatic hydrolysis sugar yield between two kinds of materials: pellets processed by UV-A pelleting and biomass not processed by UV-A pelleting in terms of total sugar yield and enzymatic hydrolysis sugar yield. Chapter 12 develops a physics-based temperature model to predict temperature in UV-A pelleting. Chapter 13 develops a physics-based density model to predict pellet density in UV-A pelleting. Finally, conclusions and contributions of this research are summarized in Chapter 14

Natural Fiber Based Composites

Entitled “Natural Fiber-Based Composites”, this Special Issue has the objective to give an inventory of the latest research in the area of composites reinforced with natural fibers. Fibers of renewable origin have many advantages. They are abundant and cheap, they have a reduced impact on the environment, and they are also independent from fossil resources. Their ability to mechanically reinforce thermoplastic matrices is well known, as their natural heat insulation ability. In the last twenty years, the use of cellulosic and lignocellulosic agricultural by-products for composite applications has been of great interest, especially for reinforcing matrices. The matrices can themselves be of renewable origin (e.g., proteins, starch, polylactic acid, polyhydroxyalkanoates, polyamides, etc.), thus contributing to the development of 100% bio-based composites with a controlled end of life. This Special Issue’s objective is to give an inventory of the latest research in this area of composites reinforced with natural fibers, focusing in particular on the preparation and molding processes of such materials (e.g., extrusion, injection-molding, hot pressing, etc.) and their characterization. It contains one review and nineteen research reports authored by researchers from four continents and sixteen countries, namely, Brazil, China, France, Italy, Japan, Malaysia, Mexico, Pakistan, Poland, Qatar, Serbia, Slovenia, Spain, Sweden, Tunisia, and Vietnam. It provides an update on current research in the field of natural fiber based composite materials. All these contributions will be a source of inspiration for the development of new composites, especially for producers of natural fibers, polymer matrices of renewable origin and composite materials. Generally speaking, these new materials are environmentally friendly and will undoubtedly find numerous applications in the years to come in many sectors. Dr. Philippe Evon Guest Edito

"Natural Fiber Based Composites", edited by Philippe Evon (Printed Edition of the Special Issue Published in Coatings)

This book is a printed edition of the Special Issue "Natural Fiber Based Composites" that was published in Coatings and edited by Dr. Philippe Evon. Dr. EVON is Research Engineer at the Laboratoire de Chimie Agro-industrielle (LCA). He has the habilitation to supervise researches (HDR). He specializes in the valorization of wastes from biomass to produce extracts and to design agromaterials. He is mainly developing studies for using biomass as raw material for: - Producing bioactive extracts through fractionation processes using “green” solvents and the twin-screw extrusion technology as continuous extraction technique. - The manufacture of agromaterials by combining single- or twin-screw extrusion technologies with molding processes (e.g. injection-molding or thermopressing). He is the Manager of the LCA’s Industrial Technological Hall “AGROMAT” dedicated to agromaterial’s (https://www6.toulouse.inra.fr/lca/AGROMAT), which is located in Tarbes (South-West of France)

Recent Perspectives in Pyrolysis Research

Recent Perspectives in Pyrolysis Research presents and discusses different routes of pyrolytic conversions. It contains exhaustive and comprehensive reports and studies of the use of pyrolysis for energy and materials production and waste management

Energy recovery from spent mushroom compost and coal tailings.

Spent mushroom compost (SMC) is an agricultural waste disposed of in an unsustainable and environmentally degrading manner - mainly in landfills. For every 1 kg of mushrooms grown, approximately 5 kg of SMC is produced, where current generation in the UK is 200,000 tJa. Coal tailings, an industrial by-product from coal mining, are also discarded untenably in lagoons; removing these deposits will eliminate the associated environmental hazards. This project aimed to combine these waste materials into a suitable 'green' fuel for industry through thermal treatment, to produce energy from a sustainable source. Not only will this alleviate the issues regarding existing waste management strategies, but will also attempt to mitigate the environmental impacts of energy generation from nonrenewable sources, such as anthropogenic climate change, through the generation of renewable energy. This PhD research has shown that both materials had high moisture contents, which negatively impacted the calorific value (CV). Drying, though expensive, would thus be required prior to pelletisation and thermal treatment. Key pelletisation parameters were identified and manipulated to control product quality. Optimal values were experimentally-determined for pellet composition (50:50 wt% SMC:coal tailing ratio), moisture (10.5 %) and pressure (6000 psi/41 MPa); such pellets had a NCV of 16.11 MJ/kg. As these pellets were still friable, additional studies were carried out to further improve pellet quality, in tenns of density, tensile strength and durability. Elevated temperatures and steam were considered, in addition to the use of starch and caustic soda binders, which were all successful to varying degrees. Combustion, gasification and pyrolysis tests compared the raw SMC to SMC-coal tailing pellets, where pellet combustion performed better than the SMC alone, and fluidised-bed combustion was more efficient than the packed-bed. Although pyrolysis worked well, the CV of the fuel products were low, whereas gasification was unsuccessful. Consequently, in-depth studies into pellet combustion in a laboratory scale fluidised-bed were perfonned, examining: (i) combustionl fluidisation air flowrates (4.9-10.7 kg/hr); (ii) fuel pellet feedrates (2.02-4.58 kg/hr); and (iii) sand bed depths (0.22-0.30 m). The impacts on temperatures, combustion efficiency and gas concentrations, including acid gas species were analysed. The most favourable operating conditions resulted in high temperatures for efficient energy recovery, with minimal pollutants, although the addition of secondary air jets could further improve the already high combustion efficiencies. While gaseous pollutants are unlikely to be an issue, as the emissions produced generally conformed to the Waste Incineration Directive, efficient particulate collection will be required to remove flyash from the gas stream prior to release to the atmosphere. Industrial implications were explored for heat and power generation, where mass and energy balances for a theoretical furnace, boiler and turbine set-up were completed for various fuel throughputs. Excess heat from the process could be utilized to dry the initial materials, but the economic analysis showed this would be costly - totalling 7) of overall pelletisation expenses. Assuming an overall process efficiency of 18.6 %, a steam turbine could generate over 10 MWe, based on an SMC-coal tailing pellet feedrate of 400,000 tJa - to simulate a large, centralised energy-from-waste facility. FLUENT, a mathematical model, was able to effectively replicate the results of the experimentation and was then used to model particle elutriation and entrainment to assess the suitability of the transport disengagement height provided