Production Of Liquid Fuels Research Articles

Utilisation of biomass for sustainable fuels and chemicals: Molecules, methods and metrics

The various catalytic methodologies for the utilisation of renewable biomass for the sustainable production of liquid fuels and commodity chemicals are reviewed. Attention is focused on second generation processes starting from lignocellulose as a sustainable feedstock, thus circumventing the food vs fuel dilemma, and on the green features of these new processes. Emphasis is also placed on the need for establishing a set of metrics for assessing the sustainability of different processes and products. It is concluded that one set of metrics is probably not sufficient to assess the sustainability of both biofuels and platform commodity chemicals. The latter can probably be evaluated on the basis of E factors (kgs waste/kg product) that take both the carbon dioxide derived from energy consumption and water usage into account, perhaps together with some form of life cycle assessment. With biofuels on the other hand, the sheer magnitude of the volumes involved present extra issues, such as land usage, and the goal is different, i.e. to produce a particular energy density for an economically viable price in a sustainable fashion.

Phosphotungstic Acid Encapsulated in Metal–Organic Framework as Catalysts for Carbohydrate Dehydration to 5‐Hydroxymethylfurfural

MIL-101, a chromium-based metal-organic framework, is known for its very large pore size, large surface area and good stability. However, applications of this material in catalysis are still limited. 5-Hydroxymethylfurfural (HMF) has been considered a renewable chemical platform for the production of liquid fuels and fine chemicals. Phosphotungstic acid, H₃PW₁₂O₄₀ (PTA), encapsulated in MIL-101 is evaluated as a potential catalyst for the selective dehydration of fructose and glucose to 5-hydroxymethylfurfural. The results demonstrate that PTA/MIL-101 is effective for HMF production from fructose in DMSO and can be reused. This is the first example of the application of a metal-organic framework in carbohydrate dehydration.

Peak oil analyzed with a logistic function and idealized Hubbert curve

A logistic function is used to characterize peak and ultimate production of global crude oil and petroleum-derived liquid fuels. Annual oil production data were incrementally summed to construct a logistic curve in its initial phase. Using a curve-fitting approach, a population-growth logistic function was applied to complete the cumulative production curve. The simulated curve was then deconstructed into a set of annual oil production data producing an “idealized” Hubbert curve. An idealized Hubbert curve (IHC) is defined as having properties of production data resulting from a constant growth-rate under fixed resource limits. An IHC represents a potential production curve constructed from cumulative production data and provides a new perspective for estimating peak production periods and remaining resources. The IHC model data show that idealized peak oil production occurred in 2009 at 83.2Mb/d (30.4Gb/y). IHC simulations of truncated historical oil production data produced similar results and indicate that this methodology can be useful as a prediction tool.

Thermochemical production of liquid fuels from biomass: Thermo-economic modeling, process design and process integration analysis

A detailed thermo-economic model combining thermodynamics with economic analysis and considering different technological alternatives for the thermochemical production of liquid fuels from lignocellulosic biomass is presented. Energetic and economic models for the production of Fischer–Tropsch fuel (FT), methanol (MeOH) and dimethyl ether (DME) by means of biomass drying with steam or flue gas, directly or indirectly heated fluidized bed or entrained flow gasification, hot or cold gas cleaning, fuel synthesis and upgrading are reviewed and developed. The process is integrated and the optimal utility system is computed. The competitiveness of the different process options is compared systematically with regard to energetic, economic and environmental considerations. At several examples, it is highlighted that process integration is a key element that allows for considerably increasing the performance by optimal utility integration and energy conversion. The performance computations of some exemplary technology scenarios of integrated plants yield overall energy efficiencies of 59.8% (crude FT-fuel), 52.5% (MeOH) and 53.5% (DME), and production costs of 89, 128 and 113 € MWh −1 on fuel basis. The applied process design approach allows to evaluate the economic competitiveness compared to fossil fuels, to study the influence of the biomass and electricity price and to project for different plant capacities. Process integration reveals in particular potential energy savings and waste heat valorization. Based on this work, the most promising options for the polygeneration of fuel, power and heat will be determined in a future thermo-economic optimization.

Thermodynamic and Experimental Analyses of the Three-Stage Calcium Looping Process

Clean-coal technologies that include carbon dioxide and sulfur capture during the production of electric power, liquid fuels, and hydrogen represent a major thrust area. The calcium looping process (CLP) is one such technology that is being developed to convert syngas obtained from coal gasification to hydrogen using a regenerable calcium oxide sorbent. It integrates the water−gas shift reaction with in situ carbon dioxide, sulfur, and halide removal at high temperatures while eliminating the need for a water−gas shift catalyst and reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors: the carbonation reactor, where the thermodynamic constraint of the water−gas shift reaction is overcome by the constant removal of the carbon dioxide product and high-purity hydrogen is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready carbon dioxide stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. In this article, the reaction chemistry occurring in the three calcium looping reactors and the performance of the reactors at various process conditions are presented through thermodynamic and experimental analyses. High-purity H2 with less than 1 ppm of H2S is obtained in the carbonation stage at a stoichiometric steam-to-carbon ratio at high pressures. Although calcination of the sorbent under realistic conditions causes severe sintering and a loss in reactivity, sorbent reactivation by hydration is effective in restoring sorbent reactivity.

Large-scale utilization of biomass energy and carbon dioxide capture and storage in the transport and electricity sectors under stringent CO 2 concentration limit scenarios

Large-scale, dedicated commercial biomass energy systems are a potentially large contributor to meeting global climate policy targets by the end of the century. We use an integrated assessment model of energy and agriculture systems to show that, given a climate policy in which terrestrial carbon is appropriately valued equally with carbon emitted from the energy system, biomass energy has the potential to be a major component of achieving these low concentration targets. A key aspect of the research presented here is that the costs of processing and transporting biomass energy at much larger scales than current experience are explicitly incorporated into the modeling. From the scenario results, 120–160 EJ/year of biomass energy is produced globally by midcentury and 200–250 EJ/year by the end of this century. In the first half of the century, much of this biomass is from agricultural and forest residues, but after 2050 dedicated cellulosic biomass crops become the majority source, along with growing utilization of waste-to-energy. The ability to draw on a diverse set of biomass-based feedstocks helps to reduce the pressure for drastic large-scale changes in land use and the attendant environmental, ecological, and economic consequences those changes would unleash. In terms of the conversion of bioenergy feedstocks into value added energy, this paper demonstrates that biomass is and will continue to be used to generate electricity as well as liquid transportation fuels. A particular focus of this paper is to show how climate policies and technology assumptions – especially the availability of carbon dioxide capture and storage (CCS) technologies – affect the decisions made about where the biomass is used in the energy system. The potential for net-negative electric sector emissions through the use of CCS with biomass feedstocks provides an attractive part of the solution for meeting stringent emissions constraints; we find that at carbon prices above $150/tCO 2, over 90% of biomass in the energy system is used in combination with CCS. Despite the higher technology costs of CCS, it is a very important tool in controlling the cost of meeting a target, offsetting the venting of CO 2 from sectors of the energy system that may be more expensive to mitigate, such as oil use in transportation. CCS is also used heavily with other fuels such as coal and natural gas, and by 2095 a total of 1530 GtCO 2 has been stored in deep geologic reservoirs. The paper also discusses the role of cellulosic ethanol and Fischer–Tropsch biomass derived transportation fuels as two representative conversion processes and shows that both technologies may be important contributors to liquid fuels production, with unique costs and emissions characteristics.

Vertical Distribution of Corn Stover Dry Mass Grown at Several US Locations

Corn (Zea mays L.) stover was identified as a renewable non-food agricultural feedstock for production of liquid fuels, biopower, and other bioproducts, but it is also needed for erosion control, carbon sequestration, and nutrient cycling. To help balance these multiple demands, our objectives were to (1) determine height distribution of corn stover biomass, (2) quantify the percentage of stover that is corn cob, and (3) develop a general relationship

Biomass Refinery as a Renewable Complement to the Petroleum Refinery

Biomass Refinery is a sequential of eleven thermochemical processes and one biological process with two initial basic treatments: prehydrolysis for lignocellulosics and low temperature conversion for biomass with medium-to-high content of lipids and proteins. The other ten processes are: effluent treatment plant, furfural plant, biodiesel plant, cellulignin dryer, calcination, fluidized bed boiler, authotermal reforming of cellulignin for syngas production, combined cycle of two-stroke low-speed engine or syngas turbine with fluidized bed boiler heat recovery, GTL technologies and ethanol from cellulose, prehydrolysate and syngas. Any kind of biomass such as wood, agricultural residues, municipal solid waste, seeds, cakes, sludges, excrements and used tires can be processed at the Biomass Refinery. Twelve basic products are generated such as cellulignin, animal feed, electric energy, fuels (ethanol, crude oil, biodiesel, char), petrochemical substitutes, some materials (ash, gypsum, fertilizers, silica, carbon black) and hydrogen. The technology is clean with recovery of energy and reuse of water, acid and effluents. Based on a holistic integration of various disciplines Biomass Refinery maximizes the simultaneous production of food, electric energy, liquid fuels and chemical products and some materials, achieving a competitive position with conventional and fossil fuel technologies, as well as payment capacity for biomass production. Biomass Refinery has a technical economical capability to complement the depletion of the conventional petroleum sources and to capture its GHGs resulting a biomass + petroleum “green” combination.

Renewable energies: Choosing the best options

Life cycle analyses of renewable energy sources focus on static accounting of energy and green house gases balances. In this work, we introduce a conceptual framework and a mathematical model to simulate the time evolution of the energy balance of energy conversion technologies. This approach complements static energy return analyses. It is based on a few technical parameters that describe a standard conversion module, a set of deployment objectives, and assumed growth rates for deployment. It is independent of working details of the conversion technology. A set of equations is formulated and solved to model the deployment of the new technology. It allows for evaluation of gross and net produced energy and for estimation of required investments. The model is applied to photovoltaic electricity in Brazil, wind electricity globally and in Brazil, and sugar cane bioethanol. The main conclusions are: (i) photovoltaic electricity, because it requires large energy investments, leads to negative net production of electricity for many years, i.e., for an extended period it is an energy sink and not source; (ii) wind electricity is an attractive option is terms of net electricity production; (iii) sugar cane bioethanol is an attractive option for liquid fuels production for the world.

Oxidation of methane by a biological dicopper centre.

Vast world reserves of methane gas are underutilized as a feedstock for production of liquid fuels and chemicals due to the lack of economical and sustainable strategies for selective oxidation to methanol1. Current processes to activate the strong C–H bond (104 kcal/mol) in methane require high temperatures, are costly and inefficient, and produce waste2. In nature, methanotrophic bacteria perform this reaction under ambient conditions using metalloenzymes called methane monooxygenases (MMOs). MMOs are thus the optimal inspiration for an efficient, green catalyst3. There are two types of MMOs. Soluble MMO (sMMO), which is expressed by several strains of methanotrophs under copper limited conditions, oxidizes methane with a well characterized catalytic diiron center4. Particulate methane monooxygenase (pMMO), an integral membrane metalloenzyme produced by all methanotrophs, is composed of three subunits, pmoA, pmoB, and pmoC, arranged in a trimeric α3β3γ3 complex5. Despite 20 years of research and the availability of two crystal structures, the metal composition and location of the pMMO metal active site are not known. Here we show that pMMO activity is dependent on copper, not iron, and that the copper active site is located in the soluble domains of the pmoB subunit rather than within the membrane. Recombinant soluble fragments of pmoB (spmoB) bind copper and exhibit propylene and methane oxidation activities. Disruption of each copper center in spmoB by mutagenesis indicates that the active site is a dicopper center. These findings resolve the pMMO controversy and provide a promising new approach to developing environmentally friendly C–H oxidation catalysts.

Techno-economic analysis of 5-nonanone production from levulinic acid

We analyze a process for production of 5-nonanone (dibutyl ketone, DBK) from levulinic acid (LA) which is a biobased platform chemical that can be produced in large quantities from a variety of lignocellulosic biomass sources. The techno-economic analysis is based on a catalytic pathway developed in lab scale. The final product (DBK) has applications as an industrial solvent and serves as a platform chemical for the production of liquid hydrocarbon fuels in the diesel and gasoline ranges. A detailed process model has been created for two different product purity levels (90% and 99%). Process economics have been studied in a discounted cash flow analysis to analyze the viability of production and relative product purification costs. The modeled process utilizes 480 metric ton/day of LA feedstock to produce 194 metric ton/day of DBK along with other by-products. Sensitivity analysis is used to identify the impact of key parameters on the minimum selling price of product. Thus, the price of the feedstock (LA) and the DBK final yield were found to be the most sensitive parameters affecting the final price of the product. With the current LA market price ($3.2 per kg) and the experimental yield of 66%, the minimum selling price estimated for a high purity DBK was $8.5 per kg, comparable to the current DBK purchase price ($9.07 per kg) but still quite high compared to the price of a typical petroleum-derived solvent such as methyl ethyl ketone ($0.77 per kg). Further improvements on the lab scale to increase the yield of DBK, and the use of inexpensive LA from the patented Biofine process, would allow the production of DBK at competitive prices for chemical and fuel applications.

Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part II: Carbohydrates

The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation2 and other products such as biocomposite materials6. Plant biomass remains one of the greatest untapped reserves on the planet4. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin5 and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation5. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant4. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose7. The protocol for analyzing the lignin components in lignocellulosic biomass is discussed in Part I3.

Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part II: Carbohydrates

The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation2 and other products such as biocomposite materials6. Plant biomass remains one of the greatest untapped reserves on the planet4. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin5 and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation5. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant4. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose7. The protocol for analyzing the lignin components in lignocellulosic biomass is discussed in Part I3.

Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part I: Lignin

The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation1 and other products such as biocomposite materials7. Plant biomass remains one of the greatest untapped reserves on the planet4. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses (matrix polysaccharides, and the polyphenol lignin6 and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls provide tensile strength to cells and the entire plants, ward off pathogens, and allow water to be transported throughout the plant; in the case of trees up to more the 100 m above ground level. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant4. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerization by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis. In this first part we focus on the analysis of the polyphenol lignin (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its lignin content by acetylbromide solubilization3, and its lignin composition in terms of its syringyl, guaiacyl- and p-hydroxyphenyl units5. The protocol for analyzing the carbohydrates in lignocellulosic biomass including cellulose content and matrix polysaccharide composition is discussed in Part II2.

Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part I: Lignin

The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation1 and other products such as biocomposite materials7. Plant biomass remains one of the greatest untapped reserves on the planet4. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses (matrix polysaccharides, and the polyphenol lignin6 and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls provide tensile strength to cells and the entire plants, ward off pathogens, and allow water to be transported throughout the plant; in the case of trees up to more the 100 m above ground level. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant4. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerization by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis. In this first part we focus on the analysis of the polyphenol lignin (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its lignin content by acetylbromide solubilization3, and its lignin composition in terms of its syringyl, guaiacyl- and p-hydroxyphenyl units5. The protocol for analyzing the carbohydrates in lignocellulosic biomass including cellulose content and matrix polysaccharide composition is discussed in Part II2.

Biomass upgrading through acid–base catalysis

The development of economic processes for the production of liquid fuels from biomass requires large investments. Therefore, the search of new catalysts for the enhancement of both the yields and the quality of biofuels is the key to improve the efficiency and reduce costs. In this scenario, acid and base catalysis plays a crucial role in most of the processes used for the production of biofuels, such as the transesterification of vegetable oils with methanol in the biodiesel process and the hydrolysis of cellulose to fermentable sugars for bioethanol production. An overview of some of the technologies currently used commercially or tested at pilot and laboratory scale, based on acid and base catalysts, is presented in this paper.

The US Department of Energy Great Lakes Bioenergy Research Center: Midwestern Biomass as a Resource for Renewable Fuels

The Great Lakes Bioenergy Research Center is one of three Bioenergy Research Centers establish by the US Department of Energy and the only one based at an academic institution. The Center’s mission is to perform basic and applied science to enable economically and environmentally sustainable production of liquid fuels derived from biomass. The research is focused on converting plant biomass into soluble sugars and the sugars into fuels. A large group focused on sustainability informs and guides the applied research to ensure that new technology will provide the required environmental benefits.

Applications of Synthetic Biology in Microbial Biotechnology

Applications of Synthetic Biology in Microbial Biotechnology

Synthetic Biology Guides Biofuel Production

The advancement of microbial processes for the production of renewable liquid fuels has increased with concerns about the current fuel economy. The development of advanced biofuels in particular has risen to address some of the shortcomings of ethanol. These advanced fuels have chemical properties similar to petroleum-based liquid fuels, thus removing the need for engine modification or infrastructure redesign. While the productivity and titers of each of these processes remains to be improved, progress in synthetic biology has provided tools to guide the engineering of these processes through present and future challenges.

Production of liquid hydrocarbon transportation fuels by oligomerization of biomass-derived C9 alkenes

A process is described to produce renewable liquid fuels, similar to existing petroleum-derived transportation fuels, through the oligomerization over solid acid catalysts of C9-alkenes derived from γ-valerolactone (GVL). Larger, non-terminal alkenes are shown to be less reactive than short chain α-alkenes for oligomerization over solid acid sites, and Amberlyst-70 has been identified to be an active and stable catalyst with sufficient acidity to couple C9-alkenes. The inhibiting effect of water on alkene oligomerization can be minimized, because C9 alkenes derived from aqueous solutions of GVL separate spontaneously from water. The effect of other impurities arising from the cascade process for production of C9 alkenes from GVL, such as 5-nonanone and 5-nonanol, has been studied. Ketones are shown to be inert, while alcohols readily dehydrate on acid sites, producing an equivalent of water, which inhibits the rate of oligomerization. Small amounts of 5-nonanol present with C9-alkenes (< 1%) have a promotional effect, due to swelling of the catalyst by polar molecules; however, large amounts of 5-nonanol lead to inhibition of oligomerization. Other more reactive alkenes present in C9-alkenes produced from GVL, such as hexene and heptene isomers, compete for acid sites with the nonene feed. These smaller, more reactive alkenes are readily coupled at high conversion. Accordingly, with this process approximately 50 kg of liquid hydrocarbons can be produced from 100 kg of GVL retaining more than 90% of its energy content.