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Due to the scarcity of fossil fuels and to population increases, there is an urgent need for renewable energy sources that can replace petroleum-derived fuels. Lignocellulosic biomass, a renewable resource, can be converted to bio-oil by fast pyrolysis and further upgraded to renewable diesel through hydroprocessing. The upgrading of oil by fast pyrolysis is the main focus of this paper. Bio-oil has a higher energy density and heating value than biomass, but it cannot be used in place of petro-diesel as it is highly unstable, polar, and immiscible with hydrocarbons. Thus upgrading is necessary as it removes oxygen-containing compounds from bio-oil. Hydroprocessing was chosen for this review paper as the method of upgrading bio-oil because there are hydrotreating units in place in refineries. To upgrade bio-oil, hydrodeoxygenation (HDO) in the presence of both a catalyst and hydrogen can replace hydrodesulfurization (the removal of sulfur compounds from crude oil). A sulfided NiMo/CoMo catalyst supported on gamma alumina is used as a benchmark catalyst for a hydrodesulfurization reaction in refineries and is considered the reference catalyst for HDO in the production of renewable diesel. The properties of renewable diesel made through hydroprocessing are similar to those of petro-diesel. Catalyst deactivation and techno-economic assessments of the whole pathway are areas that need more attention before renewable diesel can be commercialized. This review paper concentrates on the reaction mechanism in bio-oil upgrading, process parameters, and the limitations of hydroprocessing technology. This paper will be helpful for further modeling of techno-economic analysis in renewable diesel production from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Abstract: Published data were used to develop an integrated spreadsheet-based model to estimate total water requirement for 12 biomass conversion pathways. The water requirement for crop production was attributed only to the grains in the estimates since agricultural residues are produced irrespective of their use for fuel or electricity. Corn stover- and wheat straw-based ethanol production pathways are water efficient, requiring only 0.3l, whereas biopower production pathways (i.e. direct combustion and bio-oil production) require about 0.8–0.9l of water per MJ. Wheat- and corn-based ethanol production pathways consume 77 and 108l of water per MJ, respectively. Utilization of switchgrass for production of ethanol, biopower through the direct combustion, and pyrolysis consume 128, 187 and 229l of water per MJ, respectively. Biodiesel production from canola seed consumes 124l of water per MJ. Corn stover- and wheat straw-based conversion pathways are most water efficient. [ABSTRACT FROM AUTHOR]

Abstract: Large amount of hydrogen is consumed during the upgrading of bitumen into synthetic crude oil (SCO), and this hydrogen is exclusively produced from natural gas in Western Canada. Because of large amount of emission from natural gas, alternative sources for hydrogen fuel especially renewable feedstocks could significantly reduce CO2 emissions. In this study, biomass is converted to bio-oil by fast pyrolysis. This bio-oil is steam reformed near bitumen upgrading plant for producing hydrogen fuel. A techno-economic model is developed to estimate the cost of hydrogen from biomass through the pathway of fast pyrolysis. Three different feedstocks including whole-tree biomass, forest residues (i.e. limbs, branches, and tops of tree produced during logging operations), and straw (mostly from wheat and barley crops) are considered for biohydrogen production. Delivered cost of biohydrogen from whole-tree-based biomass ($2.40/kg of H2) is lower than that of forest residues ($3.00/kg of H2) and agricultural residues ($4.55/kg of H2) at a plant capacity of 2000dry tonnes/day. In this study, bio-oil is produced in the field/forest and transported to a distance of 500km from the centralized remote bio-oil production plant to bitumen upgrading plant. Feedstock delivery cost and capital cost are the largest cost contributors to the bio-oil production cost, while more than 50% of the cost of biohydrogen production is contributed by bio-oil production and transportation. Carbon credits of $133, $214, and $356/tonne of CO2 equivalent could make whole-tree, forest residues, and straw-based biohydrogen production competitive with natural gas-based H2 for a natural gas price of $5/GJ, respectively. [Copyright &y& Elsevier]

Abstract: Bio-oil, produced by fast pyrolysis of biomass, has high energy density compared to ‘as received’ biomass. The study assesses and compares the cost of transportation ($/liter of bio-oil) of bio-oil by pipeline and truck. The fixed and variable cost components of transportation of bio-oil at a pipeline capacity of 560m3/day and to a distance of 100km are 0.0423$/m3 and 0.1201$/m3/km, respectively. Pipeline transportation of bio-oil costs less than transportation by liquid tank truck (load capacity 30m3) and super B-train trailer (load capacity 60m3) above pipeline capacities of 1000 and 1700m3/day, respectively. When transportation distance is greater than 100km, bio-oil must be heated at booster stations. When transporting bio-oil by pipeline to a distance of 400km, minimum pipeline capacities of 1150 and 2000m3/day are required to compete economically with liquid tank trucks and super B-train tank trailers, respectively. [Copyright &y& Elsevier]

Abstract: Biomass-based energy and fuels are receiving attention because they are considered carbon neutral; i.e. the amount of CO2 released during combustion of this biomass is nearly the same as that taken up by the plants during their growth. Bio-oil is a dark viscous liquid consisting of hydrocarbons. These are produced by fast pyrolysis of biomass. “As-is” biomass material has a low energy density (MJm−3), hence, the cost of transporting this energy is high. Bio-oil has a high energy density as compared to “as-is” biomass material, consequently it helps in reducing the cost of energy transport. This study compares the life cycle assessment of transportation of bio-oil by pipeline with that by truck. The scope of the work includes the transportation of bio-oil by truck or pipeline from a centralized plant (supplied with forest biomass) to an end-user. Two cases are studied for pipeline transport of bio-oil: the first case considers a coal-based electricity supply for pumping the bio-oil through a pipeline; the second case considers an electricity supply from a renewable resource. The two cases of pipeline transport are compared to two cases of truck transport (truck trailer and super B-train truck). The life cycle greenhouse gas (GHG) emissions from the pipeline transport of bio-oil for the two cases of electricity supply are 345 and 17g of CO2 m−3 km−1, respectively. Similar values for transport by trailer (capacity – 30m3) and super B-train truck (capacity – 60m3) are 89 and 60g of CO2 m−3 km−1, respectively. Energy input for bio-oil transport is 3.95MJm−3 km−1 by pipeline, 2.59MJm−3 km−1 by truck and 1.66MJm−3 km−1 by super B-train truck. The results show that GHG emissions in pipeline transport are largely dependent on the source of electricity (higher for coal-based electricity). Substituting 250m3 day−1 of pipeline-transported bio-oil for coal-based electricity can mitigate about 5.1 million tonnes of CO2 per year. Overall, this study gives a comprehensive life cycle assessment of bio-oil transport comparing pipeline and truck transport. [Copyright &y& Elsevier]

Biomass is nearly carbon neutral and can be used for the production of various liquid fuels and chemicals. Decisions on biomass utilization should be based on the most economical and mature route. This study analyzes mountain pine beetle (MPB) killed wood as the feedstock for production of bio-ethanol and bio-oil and compares it with the direct combustion route to produce electricity. The MPB infestation of British Columbia’s (BC), a western province of Canada, forest has reached an epidemic proportion and is spread over an area of 10 millionha. According to the current estimates of BC‘s Ministry of Forests and Range, about 1 billion m3 of trees would be killed by MPB by 2013. This infestation would result in large scale loss of jobs and the standing dead trees are a fire hazard and if left unharvested will decay and release carbon back to the atmosphere. The cost of bio-ethanol production from a 2100dry tonne/day plant using the infested wood for two locations (one remote and other near the industry) in BC is in the range of C$0.37–C$0.40/l (C$1.40–C$1.51/gallon). Similarly, cost of bio-oil production from a 220dry tonne/day plant using the infested wood for same two locations in BC is in the range of C$0.27–C$0.29/l (C$1.02–C$1.09/gallon). The cost of producing electricity using this bio-oil is above C$100/MWh which is higher than the current power price in BC. This cost is also higher than the cost of production of electricity by direct combustion of infested wood in a boiler (C$68–C$74/MWh). [Copyright &y& Elsevier]

Hydrothermal liquefaction is one of the common thermochemical conversion methods adapted to convert high-water content biomass feedstocks to biofuels and many other valuable industrial chemicals. The hydrothermal process is broadly classified into carbonization, liquefaction, and gasification with hydrothermal liquefaction conducted in the intermediate temperature range of 250–374 °C and pressure of 4–25 MPa. Due to the ease of adaptability, there has been considerable research into the process on using various types of biomass feedstocks. Over the years, various solvents and co-solvents have been used as mediums of conversion, to promote easy decomposition of the lignocellulosic components in biomass. The product separation process, to obtain the final products, typically involves multiple extraction and evaporation steps, which greatly depend on the type of extractive solvents and process parameters. In general, the main aim of the hydrothermal process is to produce a primary product, such as bio-oil, biochar, gases, or industrial chemicals, such as adhesives, benzene, toluene, and xylene. All of the secondary products become part of the side streams. The optimum process parameters are obtained to improve the yield and quality of the primary products. A great deal of the process depends on understanding the underlined reaction chemistry during the process. Therefore, this article reviews the major works conducted in the field of hydrothermal liquefaction in order to understand the mechanism of lignocellulosic conversion, describing the concept of a batch and a continuous process with the most recent state-of-art technologies in the field. Further, the article provides detailed insight into the effects of various process parameters, co-solvents, and extraction solvents, and their effects on the products' yield and quality. It also provides information about possible applications of products obtained through liquefaction. Lastly, it addresses gaps in research and provides suggestions for future studies. [ABSTRACT FROM AUTHOR]

The conversion of lignocellulosic biomass to biofuel requires water. This study is focused on the production of hydrogenation-derived renewable diesel (HDRD) from lignocellulosic biomass. Although there has been considerable focus on the assessment of greenhouse gas (GHG) emissions, there is limited work on the assessment of the life cycle water footprint of HDRD production. This paper presents a life cycle water consumption study on lignocellulosic biomass to HDRD via pyrolysis and hydrothermal liquefaction (HTL) processes. The results of this study show that whole tree (i.e., tree chips) biomass has water requirements of 497.79 L/MJ HDRD and 376.16 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Forest residues (i.e., chips from branches and tops generated during logging operations) have water requirements of 338.58 L/MJ HDRD and 255.85 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Agricultural residues (i.e., straw from wheat, oats, and barley), which are more water efficient, have water requirements of 83.7 L/MJ HDRD and 59.1 L/MJ HDRD through fast pyrolysis and the HTL process, respectively. Differences in water use between feedstocks and conversion processes indicate that the choices of biomass feedstock and conversion pathway water efficiency are crucial factors affecting water use efficiency of HDRD production. [ABSTRACT FROM AUTHOR]

In this work, hydrothermal liquefaction (HTL) of corn stover, obtained from north Alberta farms, was performed at different temperatures of 250, 300, 350 and 375 °C, initial pressures (P i) of 300 and 600 psi and retention time (t r) of 0, 15, 30 and 60 min. All experiments were performed in a 250 mL autoclave reactor with 5 g corn stover and 30 mL de-ionized water (corresponding feed to water ratio of 1:6) in inert N 2 condition. The highest yield of heavy oil (29.25 wt%) was obtained at 300 °C, final pressure (P f) of 2200 psi and 0 min retention time. The highest yield of hydrochar (30.21 wt%) was obtained at 350 °C, P f of 3150 psi and t r of 15 min. Based on elemental analysis and energy calculation, highest carbon content and higher heating value for heavy oil was 76.32 wt% and 35.13 MJ/kg at 375 °C, P f of 600 psi and t r of 15 min; and for hydrochar it was 68.23 wt% and 24.7 MJ/kg at 350 °C, P f of 3150 psi and t r of 15 min. The GC–MS results for heavy oil indicated that majority of the compounds were phenolic in nature. SEM and FTIR results confirmed the presence of oxygen containing function groups on hydrochar surface. The gas was mainly composed of CO 2 , CH 4 , C 2 H 6 , C 2 H 4 , C 3 H 6 , C 4 H 8 , C 4 H 6 , C 5 H 12 , C 6 H 14 , and C 6 H 12. [ABSTRACT FROM AUTHOR]

Bio-oil, produced through fast pyrolysis, can act as an intermediate, which can be further upgraded to biofuels. Fast pyrolysis is done in either a centralized or a decentralized (mobile pyrolysis system [MPS]) system. In a centralized system, biomass is transported to a plant to produce bio-oil, which is upgraded in the same unit, while in a decentralized system, the mobile plant is moved to the forest to produce bio-oil, which is transported to an upgrading facility. The objective of this study is to develop supply chain models and conduct a techno-economic assessment of bio-oil production in these two systems using the developed models. For both systems, the bio-oil plant capacity is considered to be 2000 dry t d−1. Because the capacity of an MPS ranges from 10 to 100 dry t d−1, several mobile pyrolysis units are required to achieve the target bio-oil produced in the base case capacity. In this study, models were developed for each supply chain network allocation scenario/configuration for MPS site location (the radial scenario and the truncated scenario) and four relocation time scenarios were assumed (yearly, semi-annually, quarterly, and monthly). Then, bio-oil production costs were evaluated and compared those with a centralized plant. For a 2000 dry t d−1 biomass plant, bio-oil production costs are 0.241$ L−1, 0.349 $ L−1, and 0.407 $ L−1 for the centralized plant, the MPS truncated scenario (100 dry t d−1 MPS unit, yearly relocation), and the MPS radial scenario (100 dry t d−1 MPS unit, yearly relocation), respectively. • Centralized and mobile pyrolysis systems (MPS) were investigated to produce bio-oil. • The capacity of an MPS unit ranged from 10 to 100 dry t d−1. • For an MPS, two allocation scenarios were considered: radial and truncated. • Bio-oil production costs for the two systems were assessed and compared. • The base case plant capacity was varied for both systems. [ABSTRACT FROM AUTHOR]