Life cycle assessment of biochar production from southern pine

Biochar, a major co-product from the pyrolysis of lignocellulosic biomass is rich in carbon and is often used as a soil amendment to promote crop production and as a soil carbon sequestration medium to maintain long-term soil health of marginal lands. Pyrolysis is the thermal decomposition of biomass in the absence of oxygen to primarily produce bio-oil with biochar being a co-product. Biochar is also primarily produced from wood logs using conventional carbonization methods (eg. Missouri kilns). For sustainable production of biochar, the most sustainable production route is important for large-scale production of biochar for soil carbon sequestration applications. The main objectives of this study were to conduct the life cycle analysis of producing biochar using three major production routes (fast pyrolysis, slow pyrolysis and Missouri kiln) and to evaluate the life cycle energy and environmental impacts of biochar production from southern pinewood. Please click on the file below for full content of the abstract

Physical properties of charred pellets after two months of storage

Six types of charred pellets: canola straw, willow, bagasse, wheat straw, switchgrass and miscanthus, were stored for a period of two months at room temperature 25±2 °C in sealed containers. The tests were part of off gassing experiment on charred and uncharred pellets. The following physical properties of the pellets were measured: bulk density, individual pellet density, Individual pellet dimensions were similar between samples but the pellet mass ranged from 0.79 g for switchgrass to 1.13 g for bagasse pellet. Please click on the file below for full content of the abstract

Off-gassing of charred pellets during storage

The off-gassing tests for six types of charred pellets: canola straw, willow, bagasse, wheat straw, switchgrass and miscanthus, were conducted at room temperature 25±2 °C in sealed storage containers. Pairs of 2-litre sealable glass containers were filled with 800 g of each sample to approximately 75% of the container volume. One container contained charred pelles. The other container contained uncharred (untreated pellets). The two glass containers were sampled in alternate weeks for CO2, CO, O2, and CH4. Please click on the file below for full content of the abstract

Biorefinery and Hydrogen Fuel Cell Research

In this project we focused on several aspects of technology development that advances the formation of an integrated biorefinery. These focus areas include: [1] establishment of pyrolysis processing systems and characterization of the product oils for fuel applications, including engine testing of a preferred product and its pro forma economic analysis; [2] extraction of sugars through a novel hotwater extaction process, and the development of levoglucosan (a pyrolysis BioOil intermediate); [3] identification and testing of the use of biochar, the coproduct from pyrolysis, for soil applications; [4] developments in methods of atomic layer epitaxy (for efficient development of coatings as in fuel cells); [5] advancement in fermentation of lignocellulosics, [6] development of algal biomass as a potential substrate for the biorefinery, and [7] development of catalysts from coproducts. These advancements are intended to provide a diverse set of product choices within the biorefinery, thus improving the cost effectiveness of the system. Technical effectiveness was demonstrated in the pyrolysis biooil based diesel fuel supplement, sugar extraction from lignocelluose, use of biochar, production of algal biomass in wastewaters, and the development of catalysts. Economic feasibility of algal biomass production systems seems attractive, relative to the other options. However, further optimization in all paths, and testing/demonstration at larger scales are required to fully understand the economic viabilities. The various coproducts provide a clear picture that multiple streams of value can be generated within an integrated biorefinery, and these include fuels and products

Biorefinery and Carbon Cycling Research Project

In this project we focused on several aspects of technology development that advances the formation of an integrated biorefinery. These focus areas include: [ 1] pretreatment of biomass to enhance quality of products from thermochemical conversion; [2] characterization of and development of coproduct uses; [3] advancement in fermentation of lignocellulosics and particularly C5 and C6 sugars simultaneously, and [ 4] development of algal biomass as a potential substrate for the biorefinery. These advancements are intended to provide a diverse set of product choices within the biorefinery, thus improving the cost effectiveness of the system. Technical effectiveness was demonstrated in the thermochemical product quality in the form of lower tar production, simultaneous of use of multiple sugars in fermentation, use ofbiochar in environmental (ammonia adsorption) and agricultural applications, and production of algal biomass in wastewaters. Economic feasibility of algal biomass production systems seems attractive, relative to the other options. However, further optimization in all paths, and testing/demonstration at larger scales are required to fully understand the economic viabilities. The coproducts provide a clear picture that multiple streams of value can be generated within an integrated biorefinery, and these include fuels and products

Translating a Global Emission-Reduction Framework for Subnational Climate Action: A Case Study from the State of Georgia

Subnational entities are recognizing the need to systematically examine options for reducing their carbon footprints. However, few robust and comprehensive analyses are available that lay out how US states and regions can most effectively contribute. This paper describes an approach developed for Georgia—a state in the southeastern United States called “Drawdown Georgia”, our research involves (1) understanding Georgia’s baseline carbon footprint and trends, (2) identifying the universe of Georgia-specific carbon-reduction solutions that could be impactful by 2030, (3) estimating the greenhouse gas reduction potential of these high-impact 2030 solutions for Georgia, and (4) estimating associated costs and benefits while also considering how the solutions might impact societal priorities, such as economic development opportunities, public health, environmental benefits, and equity. We began by examining the global solutions identified by Project Drawdown. The resulting 20 high-impact 2030 solutions provide a strategy for reducing Georgia’s carbon footprint in the next decade using market-ready technologies and practices and including negative emission solutions. This paper describes our systematic and replicable process and ends with a discussion of its strengths, weaknesses, and planned future research

A systems analysis of biomass densification process

Pelletizing is a method of densifying biomass. Pellets have low moisture content (about 8% wet basis) for safe storage and a high bulk density (more than 500 kg/m3) for efficient transport. Biomass pellets that are usually up to 6 mm in diameter and 12 mm long, are uniform in moisture content. They can be handled, transported and fed to boilers and furnaces easily. Manufacturing of pellets involves energy intensive drying, grinding, and pelleting processes. In a typical operation, manufacturing one ton of dried pellets may use 300-3500 MJ for drying, 100-180 MJ for grinding, and 100-300 MJ for densification. The present study investigates the entire densification process using the systems analysis approach and on finding out the best alternative fuel source for biomass drying application with the lowest cost, emissions and energy consumptions. In this study, biomass drying, size reduction and compaction were studied in detail theoretically and experimentally. Drying of biomass is performed in a direct contact, co-current type rotary drum dryer. Single and triple pass rotary dryers were modeled using the lumped parameter approach. The developed models predicted the temperature and moisture profiles of hot flue gas and biomass particles and the results were in agreement with commercial rotary dryer outlet conditions. Five heating fuel sources for the dryer were compared: natural gas, coal, wet sawdust, dry sawdust and wood pellets. The combustion of fuels was modeled to predict the hot flue gas compositions and fuel requirement for the given dryer inlet conditions. A series of experiments were conducted where biomass samples were ground using a laboratory hammer mill at different screen sizes and moisture contents. Specific energy consumption of grinding biomass was estimated and used to develop the relationship between hammer mill screen size and specific grinding energy data. The laboratory hammer mill energy data were compared with commercial hammer mill data. The ground samples were analysed for particle size distribution, geometric mean particle size, bulk density and particle density. Biomass grinds' were compacted into pellets using a single pelleter unit. Compression data from the experiment were analyzed using several compaction models. Particle rearrangement and elastic and plastic deformation were the predominant compaction mechanisms during the pelleting process. Particle interlocking or local melting of constituents could have occurred at high pressures and temperatures during compaction, although this phenomenon was not examined in detail. The force-displacement data were collected and analyzed to estimate the specific energy required to compress and extrude biomass materials. It was found that more than 60% of the total energy spent during the extrusion of pellet was to overcome the wall friction. The pelleting energy could be reduced if some processing aids are used without losing the quality of compacted pellets. Or a new compaction unit may be designed and developed to eliminate the friction energy consumed during the compaction process. To conduct a systems analysis of the entire biomass densification process, a typical wood pelleting plant was chosen to evaluate the total energy consumption, environmental emissions and cost of pellet production using different alternative fuels. The process models developed in the thesis were used to predict the energy consumption and emissions during combustion process. Average emission factors were used from published literature sources to estimate the emissions of trace metals and toxic pollutants. The environmental impacts of the emissions were evaluated based on greenhouse gases, acid rain formation, smog formation and human toxicity impact potentials. A detailed engineering cost analysis was conducted to estimate the pellet production cost using different process options and fuel sources. A multi-criteria decision making method, Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) was used to rank fuel alternatives. The best fuel source was selected based on the four main criteria - energy, environmental impacts, economics and fuel quality. It was found that wood pellet or dry sawdust may be the best alternative to natural gas followed by coal and wet sawdust, if all the criteria are weighed equally. The ranking was changed to: 1) coal; 2) dry sawdust; 3) wet sawdust; 4) wood pellet; and 5) natural gas, when the weighting factor for cost was doubled.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat

Material and Environmental Properties of Natural Polymers and Their Composites for Packaging Applications—A Review

The current trend of using plastic material in the manufacturing of packaging products raises serious environmental concerns due to waste disposal on land and in oceans and other environmental pollution. Natural polymers such as cellulose, starch, chitosan, and protein extracted from renewable resources are extensively explored as alternatives to plastics due to their biodegradability, biocompatibility, nontoxic properties, and abundant availability. The tensile and water vapor barrier properties and the environmental impacts of natural polymers played key roles in determining the eligibility of these materials for packaging applications. The brittle behavior and hydrophilic nature of natural polymers reduced the tensile and water vapor barrier properties. However, the addition of plasticizer, crosslinker, and reinforcement agents substantially improved the mechanical and water vapor resistance properties. The dispersion abilities and strong interfacial adhesion of nanocellulose with natural polymers improved the tensile strength and water vapor barrier properties of natural polymer-based packaging films. The maximum tensile stress of these composite films was about 38 to 200% more than that of films without reinforcement. The water vapor barrier properties of composite films also reduced up to 60% with nanocellulose reinforcement. The strong hydrogen bonding between natural polymer and nanocellulose reduced the polymer chain movement and decreased the percent elongation at break up to 100%. This review aims to present an overview of the mechanical and water vapor barrier properties of natural polymers and their composites along with the life cycle environmental impacts to elucidate their potential for packaging applications

Two-Stage Hydrothermal Liquefaction of Sweet Sorghum BiomassPart II: Production of Upgraded Biocrude Oil

The hydrothermal liquefaction (HTL), followed by hydrodeoxygenation (HDO) of lignin-rich biomass has a potential to improve the yield and the quality of upgraded biocrude oil. In this study, the lignin-rich biomass obtained from the low-temperature HTL (stage 1) of sweet sorghum bagasse was investigated to evaluate the biocrude oil yield and its compositions using catalytic high-temperature HTL-HDO (stage 2) and was compared with the conventional, whole-stage HTL-HDO process. Biocrude oil yield was achieved up to 38% during a high-temperature HTL, while 42% was obtained after catalytic (5% Ru/C) HDO process. Up to 96% hydrocarbon content of biocrude oil was achieved, which is twice as high as that of the conventional whole-stage HTL-HDO process. Aromatic hydrocarbons and long-chain alkanes were also dominant in the upgraded biocrude oil, which collectively accounted for 28% of the total hydrocarbons. From raw sweet sorghum bagasse, the hydrocarbons yield from second-stage HTL-HDO process (11%) was substantially increased by 78%, compared to that of the whole-stage HTL-HDO process (7%). The upgraded biocrude oil could be directly processed or co-processed in the existing refinery to produce drop-in fuels