Showing papers by "Shahab Sokhansanj published in 2017"
TL;DR: In this article, the authors review contributions by Canadian researchers vis-a-vis the development of bioconversion pretreatment technologies needed to advance the commercialization of Canada's cellulosic ethanol biorefinery concept.
Abstract: Canada is endowed with abundant lignocellulosic biomass from agriculture and forestry. These sources provide a foundation for the development of Canada's cellulosic ethanol biorefinery concept which is supported by government renewable energy policy initiatives. However, the chemical structure of lignocellulosic biomass comprising carbohydrate polymers and lignin makes the structure recalcitrant to deconstruction, thereby constraining the ability of enzymes to convert these polymers into fermentable sugars without expensive and highly capital intensive pretreatment processes. The challenges are further compounded by the diversity of lignocellulosic biomass available in Canada, which typically necessitates commercial pretreatment pathways optimized for each feedstock type. In turn, these conditions constrain the development of viable business models for the commercialization of Canada's cellulosic ethanol biorefinery concept. In order to address these challenges, Canadian researchers have continued to undertake research to develop pretreatment technologies applicable to several Canadian lignocellulosic biomass sources. The objective of this paper is to review contributions by Canadian researchers vis-a-vis the development of bioconversion pretreatment technologies needed to advance the commercialization of Canada's cellulosic biorefinery concept. These pretreatment technologies include physical, physico-chemical, biological, and processes that combine these methods. This paper also highlights the role of multi-institutional science and innovation collaborative approaches for advancing Canada's cellulosic ethanol biorefinery concept further downstream.
46 citations
TL;DR: In this paper, Canada's cellulosic ethanol biorefinery concept is supported by federal and provincial government legislative ethanol mandates as well as enabling science and innovation policies for technology development to support the economic and sustainable production of ethanol and co-products from Canada's abundant supply of lignocellulosic agricultural and forestry biomass.
Abstract: Canada's cellulosic ethanol biorefinery concept is supported by federal and provincial government legislative ethanol mandates as well as enabling science and innovation policies for technology development to support the economic and sustainable production of cellulosic ethanol and co-products from Canada's abundant supply of lignocellulosic agricultural and forestry biomass. In particular, the development of pretreatment, hydrolysis, and fermentation technologies is regarded as a critical integrating step for the commercialization of cellulosic ethanol biorefinery business concepts. These critical steps are necessitated by the chemical structure of lignocellulosic biomass comprising carbohydrate polymers and lignin which constrains the ability of enzymes to convert these polymers into fermentable sugars without expensive and highly capital intensive pretreatment processes. This paper reviews science and innovation efforts by Canadian researchers in finding solutions to these constraints, in particular the development of hydrolysis and fermentation technologies. This paper also highlights the role of multi-institutional science and innovation collaborative approaches for advancing Canada's cellulosic ethanol biorefinery concept further downstream. While highlighting Canada's scientific progress, this review also outlines technology commercialization lags between basic research and full scale commercialization of a Canadian cellulosic ethanol biorefinery concept. Although this paper focuses on the near-term goal of cellulosic ethanol production, it nevertheless recognizes that ethanol is only the first step in the longer-term goal aimed at a full integrated bioconversion of lignocellulosic biomass into biofuels and a wide range of value-added biochemicals and biomaterials, consistent with the cellulosic biorefinery concept.
38 citations
TL;DR: In this article, the authors estimate the cost of drying microalgae chlorella in a conveyor belt dryer using waste heat from an industrial source and show that integrating waste heat recovery with conveyor belts dryers decreases the drying costs.
38 citations
TL;DR: In this article, three scenarios are considered to quantify the impact of the biorefinery size on the required biomass logistical resources: harvest area and contracted fields, logistics equipment fleet and the workforce to run this fleet and intermediate storage sites and their biomass inventory levels.
38 citations
TL;DR: This paper develops a statistically robust quantile-based approach for stochastic optimization under uncertainty, which builds upon scenario analysis and was found to outperform alternative methods in terms of computational efficiency and ability to meet the Stochastic problem requirements.
31 citations
TL;DR: In this paper, a one-dimensional unsteady-state heat transfer model coupled with time dependent mass loss equation of wood particles exposed to drying and pyrolysis conditions was developed.
29 citations
TL;DR: In this article, an improvement in fluidization quality and mass transfer rate was made to the pulsed fluidized bed for the fluidization of biomass particles without the need of inert bed materials by modifying the rectangular cross-section to a tapered bottom section to eliminate the dead zones.
27 citations
TL;DR: In this paper, the authors quantified the logistical resources required to develop a bioeconomy based on corn stover in the USA, including field equipment, storage sites, transportation and handling equipment, workforce, corn growers, and corn lands.
Abstract: In this study, the logistical resources required to develop a bioeconomy based on corn stover in the USA are quantified, including field equipment, storage sites, transportation and handling equipment, workforce, corn growers, and corn lands. These resources are essential to mobilize large quantities of corn stover from corn fields to biorefineries. The logistical resources are estimated over the lifetime of the biorefineries. Seventeen corn-growing states are considered for the logistical resource assessment. Over 6.8 billion gallons of cellulosic ethanol can be produced annually from 108 million dry tons of corn stover in these states. The maximum number of required field equipment (i.e., choppers, balers, collectors, loaders, and tractors) is estimated to be 194 110 units with a total economic value of about $26 billion. In addition, 40 780 trucks and flatbed trailers would be required to transport bales from corn fields and storage sites to biorefineries with a total economic value of $4.0 billion. About 88 899 corn growers need to be contracted with an annual net income of over $2.1 billion. About 1903 storage sites would be required to hold 53.1 million dry tons of inventory after the harvest season. These storage sites would take up about 35 320.2 acres and 4077 loaders with an economic value of $0.4 billion would handle this inventory. The total required workforce to run the logistics operations is estimated to be 50 567. The magnitude of the estimated logistical resources demonstrates the economic and social significance of the corn stover bioeconomy in rural areas in the USA. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd
23 citations
TL;DR: In this paper, the hydrodynamic properties of ground chip (GC) and ground pellet (GP) particles of pine wood are reported and pressure drop versus the air flow across a bed of particles is measured and the parameters of Ergun equation are estimated.
Abstract: The present work reports the hydrodynamic properties of ground chip (GC) and ground pellet (GP) particles of pine wood. Ground particles are made by grinding whole wood chips and whole wood pellets in a hammer mill equipped with a 3.2 mm screen. The average diameter of the particles measured by using image processing is 0.75 mm for GC particles and 1.31 mm for GP particles. The average density of particles is 1.33 g/cm3 for GC and 1.43 g/cm3 for GP. Pressure drop versus the air flow across a bed of particles is measured and the parameters of Ergun equation are estimated. GP particles have a minimum fluidization velocity of 15.2 cm/s which is much higher than the minimum fluidization velocity of GC particles at 8.5 cm/s. Both GC and GP particles undergo channeling and bed separation during fluidization. No bubbling regime was observed.
20 citations
TL;DR: In this paper, the drying rates of ground chip and ground pellet particles of pine were investigated, and they were ground in a hammer mill with perfora-grinder screens.
Abstract: In this research, the drying rates of ground chip and ground pellet particles of pine were investigated. Pulp wood chips and whole pellets were ground in a hammer mill. Grinder screens with perfora...
16 citations
TL;DR: In this article, the effects of flow rate, pulsation frequency, particle size distribution, fine distribution, and vibration on heat transfer were investigated, and it was found that higher gas flow rates generally yielded higher heat transfer coefficients.
Abstract: Bed-to-surface heat transfer coefficients of various biomass particles were measured in a pulsed fluidized bed. Effects of flow rate, pulsation frequency, particle size distribution, fines, and vibration on heat transfer were investigated. Higher gas flow rates generally yielded higher heat transfer coefficients. Natural frequency was found to be optimum as it offered ample bed movement and internal solid circulation without too much inactivity between pulsation cycles. Heat transfer was also heavily influenced by the interaction between gas convective and particle convective heat transfer, which was verified by the proposed heat transfer model. Two mechanisms, one of which treated the flow-on and flow-off period within a pulsation cycle individually, the other utilized the actual bubble rise velocity obtained via high-speed imaging were identified to account for the significantly different flow behavior below and above natural frequency. Good agreement was observed between experimental data and modeled r...
TL;DR: A constrained k-means algorithm and nearest neighbor approach to the BCP, which minimizes travel time and hence fuel consumption and can be incorporated into precision agricultural systems to assist in the planning of routes for loaders and bale wagons.
TL;DR: A combination of scenario analysis and heuristics are used to solve this stochastic vehicle routing problem for a network composed of a single depot and several sawmills, revealing an estimated daily energy savings of 6 GJ over the benchmark method.
TL;DR: The prediction of moisture content of alfalfa independent of bulk density in 12 seconds exhibited the potential of this technique in measuring the moisture content in batch and in production moisture measurements.
Abstract: Moisture content of a commercially important forage biomass such as alfalfa (Madicago sativa), the specific alfalfa that we used in this research, is essential at various stages of production including harvesting, baling, storing, pelleting, and cubing. The moisture content of commodities such as green tea leaves also plays a key role in retaining natural taste and color during drying. The dielectric constants and the dielectric loss factors of chopped alfalfa were measured with moisture contents between 11.5% and 73%, wet basis (wb), and bulk densities ranging over 139 kg·m-3 to 716 kg· m-3. They were measured at 10 frequencies between 1 and 18 GHz at 20 °C with an open ended coaxial probe with 20 inputs for artificial neural networks. A three-layer neural network with 20 inputs, five hidden nodes, and one output for moisture content was built on an error back-propagation algorithm with momentum and adaptive learning techniques to predict the moisture content of alfalfa. It was independent of bulk density with a root-mean-square error of 1.09%. The prediction of moisture content of alfalfa independent of bulk density in 12 seconds exhibited the potential of this technique in measuring the moisture content of alfalfa and other medicinal and cash crops in batch and in production moisture measurements.
TL;DR: In this article, the effects of varying the mass and volume of ground chip and pellet particles on the particle drying rate were analyzed, and a variable radius first order drying model was found to fit the experimental data better than a fixed radius model.
TL;DR: In this paper, the authors analyzed hourly weather data (temperature, humidity, and rainfall) from the Typical Meteorological Year v.3 (TMY3) dataset developed by the National Renewable Energy Laboratory.
Abstract: . The moisture content of a maturing crop varies as the harvest season progresses. For crop residues such as corn stover, moisture content at the time of harvest can be as high as 75% (wet mass basis) to less than 20% depending on the geographic location (climate conditions) and stage of harvest. Biomass moisture content is critical for baling and extended storage. It is therefore essential to have an estimate of the quantities of corn stover available as wet or dry for various parts of the U.S. To this end, we analyzed hourly weather data (temperature, humidity, and rainfall) from the Typical Meteorological Year v.3 (TMY3) dataset developed by the National Renewable Energy Laboratory. A recently published set of equations for calculating the moisture content of stover as a function of hourly temperature, humidity, and rainfall were used. The annual start and end of corn grain harvest along with annual grain production (in bushels) for each state were extracted from USDA National Agricultural Statistics Service reports. Using these datasets and moisture sorption equations, the percentage of corn stover tonnage with moisture content less than 20%, between 20% and 40%, or greater than 40% was estimated from the length of time that the biomass was in these moisture content ranges. These calculations were carried out for several locations within each of the states for which TMY data were available. It was concluded that about 37.2% of corn stover is dry ( 40% moisture content) nationwide. The remaining 27.0% of corn stover is between 20% and 40% moisture content.