Diesel Blendstocks Research Articles

Industrial waste to diesel engines: A novel hydrothermal co-liquefaction approach to produce diesel blendstocks

A mixture of industrial rejects containing textile and chemical wastes were co-liquefied using industrial wastewater at different mixture compositions and temperatures to produce bio-crude. The bio-crude yield from a 75:25 w/w textile:chemical waste was 64.5 wt.% at 325 °C and 30 min, and it was further distilled in 150–350 °C range for diesel blending. The distillate was rich in C13–C24 aliphatic hydrocarbons with H/C mole ratio of 1.86. The bio-crude-diesel blends were tested for their compatibility and efficiency in diesel engines, thus presenting an end-to-end approach from wastes to diesel-range fuels. The blends exhibited similar properties to that of commercial diesel. The 5 vol.% blend of the distillate with commercial diesel exhibited performance and emission characteristics similar to diesel when used in an internal combustion engine. The hydrochars exhibited calorific values between 14 and 32 MJ kg−1, and the aqueous phase contained Na+, K+, Ca2+, Cl–, and SO42– ions.

Characterizing the Opportunity Space for Sustainable Hydrothermal Valorization of Wet Organic Wastes.

Resource recovery from wet organic wastes can support circular economies by creating financial incentives to produce renewable energy and return nutrients to agriculture. In this study, we characterize the potential for hydrothermal liquefaction (HTL)-based resource recovery systems to advance the economic and environmental sustainability of wastewater sludge, FOG (fats, oils, and grease), food waste, green waste, and animal manure management through the production of liquid biofuels (naphtha, diesel), fertilizers (struvite, ammonium sulfate), and power (heat, electricity). From the waste management perspective, median costs range from -193 $·tonne-1 (FOG) to 251 $·tonne-1 (green waste), and median carbon intensities range from 367 kg CO2 eq·tonne-1 (wastewater sludge) to 769 kg CO2 eq·tonne-1 (green waste). From the fuel production perspective, the minimum selling price of renewable diesel blendstocks are within the commercial diesel price range (2.37 to 5.81 $·gal-1) and have a lower carbon intensity than petroleum diesel (101 kg CO2 eq·MMBTU-1). Finally, through uncertainty analysis and Monte Carlo filtering, we set specific targets (i.e., achieve wastewater sludge-to-biocrude yield >0.440) for the future development of hydrothermal waste management system components. Overall, our work demonstrates the potential of HTL-based resource recovery systems to reduce the costs and carbon intensity of resource-rich organic wastes.

New Renewable Hydrothermal Liquefaction (HTL) Biofuel: A Combustion and Emissions Study in an Optical Engine

This study involves the investigation of municipal solid waste (MSW) based biofuel in order to demonstrate its utilization as a diesel blendstock in a compression ignition (CI) engine. The biofuel was produced from the Hydrothermal Liquefaction (HTL) process. The tested biofuels represented both distilled (known as nonupgraded HTL biofuel) and hydrotreated (known as upgraded HTL biofuel) fuels, obtained from raw bio-crude. The effects of the HTL biofuel and diesel blending on the combustion and emission characteristics were investigated. A comparative study of nonupgraded and upgraded HTL biofuel in terms of combustion and emissions was conducted. The upgraded HTL biofuel was blended with reference diesel (RD) by 5%, 10%, and 40% by weight, respectively, and the nonupgraded HTL biofuel was blended with RD by 10% by weight. The experiments were conducted in an optically accessible compression ignition chamber (OACIC) with engine-like thermodynamic conditions. The parameters were recorded at a constant speed and at fixed thermodynamic conditions. The heat release rate (HRR), in-cylinder pressure, ignition delay (ID), flame lift-off length (FLOL), and in-flame soot were measured. The PM, CO, NOx, and CO2 were also recorded. In summary, the HTL blends exhibited a close resemblance to the reference diesel across a range of combustion parameters and regulated emissions. Furthermore, the upgraded HTL blends outperformed the nonupgraded blend in terms of both combustion characteristics and emissions.

The effect of 1-octanol blending on the multi-stage autoignition of conventional diesel and HVO fuels

Alternative fuels can reduce the carbon intensity of diesel engine use, and a detailed understanding of the combustion process for these fuels can minimize resulting fuel consumption and emissions. 1-Octanol has been considered as an alternative diesel fuel, but little work evaluating its combustion process in detail exists. In this work, ignition of 1-octanol, both pure and in blends with conventional and renewable diesel base fuels, is analyzed in a constant volume combustion chamber and a modified Cooperative Fuels Research Octane Rating engine operating in homogeneous charge compression ignition combustion mode. 1-Octanol blending reduced the derived cetane number of either base fuel, but modest increases in chamber temperature at injection could compensate for even dramatic reductions in derived cetane number. It was further found that greater amounts of low-temperature heat release were required to reach main ignition as the 1-octanol blending volume fraction was increased in the constant volume combustion chamber. This finding is attributed to the changing local equivalence ratio, as the reacting spray diffuses further into the chamber and approaches the (lean) global equivalence ratio as the ignition delay grows. Finally, it was found that, despite lowering the derived cetane number, 1-octanol blending enhanced the reactivity of the conventional diesel fuel observed in the variable compression ratio engine. This finding is attributed to the higher rates of hydrogen abstraction from the weaker average C–H bonds in 1-octanol, as hydrogen abstraction governs intermediate temperature heat release. These findings clarify the effect of 1-octanol on physical processes and the various chemical regimes of heat release in compression ignition. The dependence of the effects of 1-octanol blending on the base fuel are emphasized, as these can inform the deployment of 1-octanol as a diesel blendstock. Application of these results can support the optimization of conventional combustion strategies for use with 1-octanol, as well as the development of 1-octanol-fueled low-temperature combustion strategies with the associated promise of very low criteria pollutant emissions.

Automotive sustainable diesel blendstock production through biocrude obtained from hydrothermal liquefaction of municipal solid waste

Hydrothermal liquefaction (HTL) bio-crude is known as a potential alternative to conventional fossil fuels in the existing infrastructure. Although HTL has enormous potential as a process for renewable fuel production, developing economically viable HTL-based value-chains has encountered extensive challenges owing to the contaminants and the complex matrix it possesses. Therefore, devising efficient downstream processing and blending strategies is of high importance. This study evaluates different bio-crude refining scenarios; namely 1) pre-stabilization using partial hydrotreating, 2) fractionation through vacuum distillation and 3) the integration of the former processes, in producing a compliant HTL-derived road diesel blendstock. The combination of the distillation fractions is optimized through a multi-objective optimization method minimizing the deviation from the road diesel standard specifications. The optimized blend fuels are combusted in an optical accessible compression-ignited chamber (OACIC) to assess the exhaust emissions. Partial hydrotreating successfully improves the distillation recovery from 22.7 wt% (raw bio-crude) to 55.6 wt% along with a significant improvement in the physicochemical properties. The hydrotreated bio-crude distillate mixture is an adequate diesel blendstock that complies with the standard specification by at least 5 wt% contribution to the finished fuel. The results also show that with a slight improvement in the desulphurization of bio-crude, the bio-blendstock share can increase up to 10 wt%. With the comparable GHG emission profile to the reference diesel, the hydrotreated bio-crude distillate mixture heralds a promising green blendstock that can significantly contribute to meeting the current road transport diesel fuel demand.

Application of Alkoxyalkanoates (AOAs) as Renewable Diesel Blendstocks from Chemical Coupling of High-Yield Fermentation Products

Combustion of liquid fossil fuels for transportation is a major source of carbon emissions only partially offset by the incumbent renewable alternatives─biodiesel, renewable diesel, and ethanol. New renewable ground transportation fuels derived from abundant sources of biomass, and utilizing carbon-efficient bioprocessing, are needed to further offset fossil fuel use. Low carbon intensity liquid fuels are especially required for medium- to heavy-duty engine architectures supporting the long-range transportation fleet. Realization of substantial carbon efficiency gains in renewable fuel production can be achieved by extending feedstocks beyond lipids, which are the primary bioderived source material for biodiesel and renewable diesel. Toward these ends, chemical upgrading of the high carbon yield, central metabolism-derived intermediates, glycolic acid, lactic acid, and 4-hydroxybutyrate with various fermentation-derived alcohols was accomplished using standard chemical transformations to provide a class of compounds that show promise as an alternative to petroleum diesel. Fuel property testing of these C7–C22 hydroxyalkanoate-derived compounds demonstrated improved cold temperature performance compared to biodiesel (cloud point temperatures < −50 °C) and improved derived cetane number (DCN) and sooting metrics compared to renewable diesel, providing the technical basis for a new high-performance renewable blendstock for decarbonization of heavy-duty transport.

Tunable Production of Diesel Bio-Blendstock by Rhenium-Catalyzed Hydrogenation of Crude Hexanoic Acid from Grape Pomace Fermentation

The transition from fossil resources to renewable ones represents a pressing need. The acidogenic fermentation of biomass-derived ethanol to carboxylic acids represents a novel and smart possibility, opening the way for the production of further value-added bio-products through cascade chemical approaches. In this work, the hydrogenation of commercial hexanoic acid to give 1-hexanol/hexyl hexanoate mixtures was preliminary studied in the presence of commercial rhenium catalysts (Re2O7 and 5 wt% Re/C), which resulted as mainly active and selective towards 1-hexanol. On the other hand, the use of niobium phosphate as the acid co-catalyst markedly shifted the selectivity towards hexyl hexanoate. Moreover, 5 wt% Re/C and physical mixtures of (5 wt% Re/C + niobium phosphate) were further tested for the hydrogenation of crude hexanoic acid obtained through fermentation of white grape pomace, confirming the promising performance of these catalytic systems and their recyclability. For the first time, the employment of 1-hexanol/hexyl hexanoate mixtures as a diesel blendstock was evaluated, highlighting a significant reduction of soot and CO emissions, without any significant change in the engine performance. The promising properties of these oxygenated additives are favorable for the partial replacement of traditional fossil fuels, in accordance with the short-term goals of EU countries.

Biorefinery upgrading of herbaceous biomass to renewable hydrocarbon fuels, Part 2: Air pollutant emissions and permitting implications

The development of advanced biofuel production facilities is still at a nascent stage, and the biorefineries could face challenges in obtaining air permits required for their construction and operation because they are novel emission sources. To fill gaps in knowledge regarding potential emissions, we perform a detailed federal regulatory analysis and estimate air pollutant emissions for an advanced biorefinery that produces renewable diesel blendstock (RDB) from lignocellulosic biomass via aerobic respiration documented in Part 1 of the paper. We evaluate 12 design permutations that include two feedstocks, a uniform format blend (UFB) and corn stover; three biorefinery scales, 2,000, 5,200, and 9,100 dry metric tons per day (dmtd) of lignocellulosic biomass feed; and two lignin uses, as either a boiler fuel or for pellet production. We also evaluate 6 additional design permutations by incorporating non-emitting renewable power, which could reduce up to 63% carbon monoxide (CO) and nitrogen oxides (NO x ) each, 21% volatile organic compounds (VOC), and 43% hazardous air pollutants (HAP) as opposed to on-site power production, for biorefineries that produce pellets, using either UFB or corn stover. Our results indicate that all 18 design permutations would be classified as a major source under the Clean Air Act's New Source Review program without additional emission controls. Compared to using lignin as a boiler fuel, diverting lignin for pellet production reduces the emissions of CO up to 88%, NO x up to 73%, sulfur dioxide (SO 2 ) up to 99%, VOCs up to 72%, and HAPs up to 66%. Additionally, we explore control options that could further reduce emissions and assess whether reductions are enough to achieve minor source classification. Insights from our analysis can help biorefinery developers and regulators develop permitting strategies to mitigate investment risks. • Air emissions from 12 biorefinery process design variations are quantified. • Biorefineries would be classified as major sources without additional controls. • Control options are available for compliance with applicable federal regulations. • Diverting lignin for pellet production could reduce air emissions by at least 66%. • Integrating non-emitting renewable power could help achieve minor source.

Blended fuel property analysis of butyl-exchanged polyoxymethylene ethers as renewable diesel blendstocks

Methyl-terminated polyoxymethylene ethers (MM-POMEs), having the formula CH3O-(CH2O)n-CH3 (n = 3–6), are a class of oxygenates with desirable diesel-like fuel properties including high cetane number and low soot formation. However, their low energy density and high water-solubility present barriers to their adoption. Both concerns were recently addressed by our research group by synthesizing a mixture of POME structures having butyl end-groups and n = 1–6, termed B*POME1–6. B*POME1–6 maintained the advantageous properties of the parent MM-POMEs, and exhibited improved energy density and most notably, dramatically decreased water solubility. For evaluation against a set of criteria for a blended diesel blendstock, a 20 vol% blend of B*POME1–6 with a base diesel fuel was investigated here. Oxidation stability, cetane number, sooting tendency, lubricity and conductivity were improved in the B*POME1–6 blend compared with the base diesel, while also maintaining the flash point, cloud point, energy density, viscosity, and boiling point requirements. The B*POME1–6 product demonstrated a synergistic blending behavior at 10 vol% and a linear blending behavior at 20–30 vol% blends, in agreement with similar POME blends at comparable blend levels. Finally, common environmental and toxicity models performed on B*POME1–6 component molecules suggested they have a greater propensity to partition into the water compartment compared to a common diesel surrogate, but with a lower tendency to bioaccumulate.

A Simple Process for the Dimerization and Cross-Coupling of Isoprene and Myrcene to High-Performance Jet and Diesel Blendstocks

A Simple Process for the Dimerization and Cross-Coupling of Isoprene and Myrcene to High-Performance Jet and Diesel Blendstocks

Synthesis of Butyl-Exchanged Polyoxymethylene Ethers as Renewable Diesel Blendstocks with Improved Fuel Properties

Methyl-terminated polyoxymethylene ethers (MM-POMEs), having the formula CH3O–(CH2O)n–CH3 (n = 3–5), are a high-cetane, low-sooting group of oxygenates that have recently attracted attention as pot...

Property predictions demonstrate that structural diversity can improve the performance of polyoxymethylene ethers as potential bio-based diesel fuels

High emissions of particulate matter from diesel engines presents a serious risk to human health and the environment. The addition of oxygenated molecules to diesel fuels has been shown to reduce soot formation during combustion. Polyoxymethylene ethers (POMEs) are a novel class of oxygenated molecules that can be produced from biomass and that have the potential to be used as soot-reducing diesel fuel blendstocks. However, only a few variations of these molecules have been studied thus far, and those that have been characterized present significant disadvantages that could compromise current liquid fuel systems and diesel engines. Using a variety of structure–activity models, we evaluated 67 POMEs to predict the effects of structural variations on important fuel properties. Prediction accuracy was assessed by comparing predictions with measurements for a subset of structures. Nine POME molecules were identified as having potential to reduce soot formation by over 75% compared to conventional diesel fuels while being compatible with current liquid fuel infrastructure, maintaining optimal engine performance, and presenting a minimal risk to the environment. None of these nine POMEs has been previously identified as a potential diesel blendstock. This is the first evaluation of POMEs as a class of molecules and the results guide research on the synthesis, properties, and engine performance of POMEs.

Compatibility of Biologically Derivable Alcohols, Alkanes, Esters, Ketones, and an Ether as Diesel Blendstocks with Fuel System Elastomers

The compatibility of 11 bioderivable diesel blendstocks with 17 elastomer materials common to fuel storage, dispensing, and delivery systems was evaluated though volume and hardness measurements. T...

Economic impacts of feeding microalgae/wood blends to hydrothermal liquefaction and upgrading systems

Experimental work observed a synergetic effect of using microalgae/wood blended feedstocks for hydrothermal liquefaction (HTL) conversion with a yield advantage over using microalgae only or wood only as the feedstock. Experimental results for HTL and hydrotreating were used to develop the techno-economic analysis (TEA) for a blended feedstock HTL and biocrude upgrading system. For the blended feedstock system, wood is blended with algae feedstock during the lower algal productivity seasons (winter, fall, and spring) to match the maximum algal seasonal production rate. Adding woody biomass led to a 34% larger plant scale than the algae-only system with the same assumptions for algae seasonal productivity. In addition, low-cost woody biomass led to lower blended feedstock cost than the algae-only case. Blended feedstock also eliminated the need for drying a portion of the algae during summer and spring for winter and fall use, a requirement of the algae-only case, and thus reduced the related capital and operating costs. Economic analysis results indicated that, with feeding of microalgae/wood blended feedstock, the minimum fuel selling price (MFSP) to produce naphtha and diesel blendstock was reduced by 21% and the conversion-only cost (excluding cost for feedstock) was reduced by 13% compared to the algae-only case. Sensitivity analysis identified algae feedstock cost, algae blend ratios, and biocrude yields as key factors affecting the MFSP of the blended feedstock system.

Single-Step Conversion of Ethanol to n-Butene over Ag-ZrO2/SiO2 Catalysts

Ethanol is a promising platform molecule for production of a variety of fuels and chemicals. Of particular interest is producing middle distillate fuels (i.e., jet and diesel blendstock) from renew...

Highly Selective Cross-Etherification of 5-Hydroxymethylfurfural with Ethanol

Etherification of 5-hydroxymethylfurfural (HMF) and ethanol to yield ethoxymethylfurfural (EMF) is an important reaction for producing diesel blendstocks from biomass resources. This aqueous-phase ...

Renewable diesel blendstocks and bioprivileged chemicals distilled from algal biocrude oil converted via hydrothermal liquefaction

Hydrothermal liquefaction (HTL) has been demonstrated as a promising technology to convert algae into biocrude oil.

Camphorane as a Renewable Diesel Blendstock Produced by Cyclodimerization of Myrcene

Camphorene was synthesized by the thermal Diels–Alder cyclodimerization of myrcene and subsequently hydrogenated to produce camphorane. On the basis of common fuel metrics (density, lower heating v...

Methyl ketone production by Pseudomonas putida is enhanced by plant-derived amino acids.

Plants are an attractive sourceof renewable carbon for conversion to biofuels and bio-based chemicals. Conversion strategies often use a fraction of the biomass, focusing on sugars from cellulose and hemicellulose. Strategies that use plant components, such as aromatics and amino acids, may improve the efficiency of biomass conversion. Pseudomonas putida is a promising host for its ability to metabolize a wide variety of organic compounds. P. putida was engineered to produce methyl ketones, which are promising diesel blendstocks and potential platform chemicals, from glucose and lignin-related aromatics. Unexpectedly, P. putida methyl ketone production using Arabidopsis thaliana hydrolysates was enhanced 2-5-fold compared with sugar controls derived from engineered plants that overproduce lignin-related aromatics. This enhancement was more pronounced (~seven-fold increase) with hydrolysates from nonengineered switchgrass. Proteomic analysis of the methyl ketone-producing P. putida suggested that plant-derived amino acids may be the source of this enhancement. Mass spectrometry-based measurements of plant-derived amino acids demonstrated a high correlation between methyl ketone production and amino acid concentration in plant hydrolysates. Amendment of glucose-containing minimal media with a defined mixture of amino acids similar to those found in the hydrolysates studied led to a nine-fold increase in methyl ketone titer (1.1 g/L).

Screening of Potential Biomass-Derived Streams as Fuel Blendstocks for Mixing Controlled Compression Ignition Combustion

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Mixing controlled compression ignition, i.e., diesel engines are efficient and are likely to continue to be the primary means for movement of goods for many years. Low-net-carbon biofuels have the potential to significantly reduce the carbon footprint of diesel combustion and could have advantageous properties for combustion, such as high cetane number and reduced engine-out particle and NO&lt;sub&gt;x&lt;/sub&gt; emissions. We developed a list of over 400 potential biomass-derived diesel blendstocks and populated a database with the properties and characteristics of these materials. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a blendstock met the basic requirements for handling in the diesel distribution system and use as a blend with conventional diesel. Criteria included cetane number ≥40, flashpoint ≥52°C, and boiling point or T90 ≤338°C. Blendstocks needed to be soluble in diesel fuel, have a toxicity no worse than conventional diesel, not be corrosive, and be compatible with fuel system elastomers. Additionally, cloud point or freezing point below 0°C was required. Screening based on blendstock properties produced a list of 12 that were available as fuels or reagent chemicals or could be synthesized by biofuels production researchers. This group included alkanes, alcohols, esters, and ethers. These candidates were further examined for their impact fuel properties upon blending with a conventional diesel fuel. Blend properties included cetane number, lubricity, conductivity, oxidation stability, and viscosity. Results indicate that all 12 candidates can meet the basic requirements for diesel fuel blending, although in some cases would require additive treatment to meet requirements for lubricity, conductivity, and oxidation stability.&lt;/div&gt;&lt;/div&gt;