Blend Stock Research Articles

Integration of chemical catalysis with extractive fermentation to produce fuels

Nearly one hundred years ago, the fermentative production of acetone by Clostridium acetobutylicum provided a crucial alternative source of this solvent for manufacture of the explosive cordite. Today there is a resurgence of interest in solventogenic Clostridium species to produce n-butanol and ethanol for use as renewable alternative transportation fuels. Acetone, a product of acetone-n-butanol-ethanol (ABE) fermentation, harbours a nucleophilic α-carbon, which is amenable to C-C bond formation with the electrophilic alcohols produced in ABE fermentation. This functionality can be used to form higher-molecular-mass hydrocarbons similar to those found in current jet and diesel fuels. Here we describe the integration of biological and chemocatalytic routes to convert ABE fermentation products efficiently into ketones by a palladium-catalysed alkylation. Tuning of the reaction conditions permits the production of either petrol or jet and diesel precursors. Glyceryl tributyrate was used for the in situ selective extraction of both acetone and alcohols to enable the simple integration of ABE fermentation and chemical catalysis, while reducing the energy demand of the overall process. This process provides a means to selectively produce petrol, jet and diesel blend stocks from lignocellulosic and cane sugars at yields near their theoretical maxima.

Effect of blends of Diesel and Palm-Castor biodiesels on viscosity, cloud point and flash point

Many countries are promoting the use of biodiesel as a direct replacement for, or blend stock component with petroleum based diesel fuel using policy instruments that aim to gradually increase the use of vegetable oil biodiesel–diesel ratio from the current (or inexistent) blend to values among 15–20% by an specific upcoming year. For the particular use of palm oil as biomass raw material in the diesel–palm oil biodiesel (Diesel–POB) blend that goal could bring some difficulties because the high content of saturated fatty acids in POB could confer a problematic high cloud point to the fuel mixtures. On the other hand, the use of castor oil biodiesel in the blends could lower the cloud point value but, simultaneously, increase the viscosity of the diesel–biodiesel blends. In this article there were evaluated three properties (viscosity, cloud point and flash point) of binary mixtures castor oil biodiesel (COB), palm oil biodiesel (POB) and diesel fuel. It was also measured the cloud point for some ternary bends of Diesel/POB/COB. It was found that diesel–castor oil biodiesel (DieselCOB) blends showed appropriate and approximately the same cloud point temperatures when the biodiesel concentration in those mixtures was under 40% in volume. The use of palm oil biodiesel–castor oil biodiesel (POBCOB) blends to obtain a type of pure biodiesel with both low cloud point and viscosity was not a practical option. Experimental data were also compared with the predictions of different published models for diesel–biodiesel mixtures. The general thermodynamic expressions used for estimation of viscosity and cloud point for liquid mixtures showed lower deviations from experimental values properties predictions from other proposed empirical models.

Investigating the techno‐economic trade‐offs of hydrogen source using a response surface model of drop‐in biofuel production via bio‐oil upgrading

This study presents a parametric fitting of the economics of bio‐oil stabilization and hydroprocessing to naphtha and diesel range blend fuel. The data is fit with a response surface model (RSM). Technical variables evaluated in this study are rate of bio‐oil upgrading and natural gas input rate. Economic variables considered include bio‐oil, natural gas, hydrogen, catalyst, capital, and fossil carbon costs.Our base case consists of a 1440 tonnes per day bio‐oil upgrading biorefinery concept design for the production of naphtha and diesel range blend stock fuels. The RSM represents variation around this base case. The process model includes reforming, stabilization, and hydroprocessing sections. Total project investment for this concept is $171.5 million or $2.34 per gallon of bio‐oil input capacity. This base case biorefinery generates 71.8 million gallons of fuel (5182 barrels per day) at a minimum fuel selling price (MFSP) of $2.48 per gallon.We investigated the techno‐economic impacts of different hydrogen sources on the bio‐oil upgrading process. Hydrogen from bio‐oil reforming results in the lowest biofuel emissions but is not always economical. A portion of available bio‐oil should be converted to hydrogen under two main conditions: the cost of hydrogen from bio‐oil is lower than procuring hydrogen from other sources and the lost income due to a lower biofuel output; and/or when there is a market or policy constraint limiting fossil fuel use. Results indicate that to minimize fuel costs, the amount of bio‐oil upgraded should decrease from ≥90% to 80% as bio‐oil prices decline from $1.37 to $0.70 per gallon depending on market conditions. Carbon emission constrains such as those mandated by the Renewable Fuels Standard (RFS) could force bio‐oil upgrading rates to less than 90%.

Manufacture, Qualification and Approval of New Aviation Turbine Fuels and Additives

Energy consumption has always been instrumental in raising the living standards of the people of this planet. Unfortunately, it is predicted that the fossils fuels which have heretofore been the main source of energy will be practically depleted in 50 years. It is also now abundantly clear that the use of the fossil fuels involves environmentally damaging emissions such as CO, SOand a variety of Nitrogen Oxides. The lifting of hundreds of millions of people in the developing world from poverty into the middle class has greatly increased the demand for energy, which is currently derived mainly from fossil fuels and thus dramatically exacerbating the pollution trends. Due to the limiting nature of the fossil fuels and their undesirable pollution effects, there is a concerted effort to find alternative and less polluting energy sources. Since the aviation industry is on the cusp of unprecedented expansion to accommodate the travelling needs of the rapidly increasing middle class of the emerging economies, the quest for alternative fuels, such as biofuels, for aviation has assumed a form of urgency. Since the approval of the use of Fischer Tropsch Hydroprocessed Synthesized Paraffinic Kerosenes (SPK) produced by Sasol as a blending stock in DEFSTAN 91-91 research has been ongoing to introduce feedstock from alternative feedstock using different methods. However, the use of biofuels in aviation presents greater restrictions for any candidate fuel and may require extensive changes to engines. The aim of this paper is to review and provide a guideline in the production and certification of aviation 22.

Paving Asphalt Products Exhibit a Lack of Carcinogenic and Mutagenic Activity

A paving asphalt and a vacuum residuum (derived from crude oil by atmospheric and subsequent vacuum distillation and used as a blend stock for asphalt) were tested in skin carcinogenesis assays in mice and in optimized Ames assays for mutagenic activity. In the skin cancer tests, each substance was applied twice weekly for 104 weeks to the clipped backs of groups of 50 male C3H mice. Neither the paving asphalt nor the vacuum residuum (30% weight/volume and 75% weight/weight in US Pharmacopeia mineral oil, respectively) produced any tumors. The positive control benzo[a]pyrene (0.05% w/v in toluene) induced tumors in 46 of 50 mice, demonstrating the effectiveness of the test method. Salmonella typhimurium tester strain TA98 was used in the optimized Ames assay to evaluate mutagenic potential. Dimethylsulfoxide (DMSO) extractions of the substances were not mutagenic when tested up to toxic limits. Thus, under the conditions of these studies, neither the paving asphalt nor the vacuum residuum was carcinogenic or mutagenic.

Techno-economic analysis of autotrophic microalgae for fuel production

It is well-established that microalgal-derived biofuels have the potential to make a significant contribution to the US fuel market, due to several unique characteristics inherent to algae. Namely, autotrophic microalgae are capable of achieving very high efficiencies in converting solar energy into biomass and oil relative to terrestrial oilseed crops, while at the same time exhibiting great flexibility in the quality of land and water required for algal cultivation. These characteristics allow for the possibility to produce appreciable amounts of algal biofuels relative to today’s petroleum fuel market, while greatly mitigating “food-versus-fuel” concerns. However, there is a wide lack of public agreement on the near-term economic viability of algal biofuels, due to uncertainties and speculation on process scale-up associated with the nascent stage of the algal biofuel industry. The present study aims to establish baseline economics for two microalgae pathways, by performing a comprehensive analysis using a set of assumptions for what can plausibly be achieved within a five-year timeframe. Specific pathways include autotrophic production via both open pond and closed tubular photobioreactor (PBR) systems. The production scales were set at 10 million gallons per year of raw algal oil, subsequently upgraded to a “green diesel” blend stock via hydrotreating. Rigorous mass balances were performed using Aspen Plus simulation software, and associated costs were evaluated on a unit-level basis. Upon completing the base case scenarios, the cost of lipid production to achieve a 10% return was determined to be $8.52/gal for open ponds and $18.10/gal for PBRs. Hydrotreating to produce a diesel blend stock added onto this marginally, bringing the totals to $9.84/gal and $20.53/gal of diesel, for the respective cases. These costs have potential for significant improvement in the future if better microalgal strains can be identified that would be capable of sustaining high growth rates at high lipid content. Given that it is difficult to maximize both of these parameters simultaneously, it was determined that the near-term research should focus on maximizing lipid content as it offers more substantial cost reduction potential relative to an improved algae growth rate. Additional economic sensitivity studies were established to identify other important cost drivers, and a resource assessment comparison was made to evaluate parameters such as water and CO 2 requirements.

Comparison of Biomass-Derived Turbine Fuels with the Composition-Explicit Distillation Curve Method

In recent years, civilian and military users of aviation kerosene have been interested in expanding the scope of fuel feed stocks to include nonpetroleum sources. The most well-known examples of such alternative sources of fuel are the Fischer−Tropsch fluids made from coal and natural gas. In addition to these feed stocks, there is great interest in biomass derived sources for aviation fuels. It is unlikely that a completely new, drop-in replacement fuel will be successful in the foreseeable future, but an intermediate goal is to extend or enhance present petroleum derived stocks. For this to be done on a rational basis, careful attention must be paid to fuel properties, one of the most important of which is the fluid volatility as expressed by the distillation curve. In this paper, we apply the composition explicit distillation curve method to examine three aviation fuels made from camelina (a genus within the flowering plant family Brassicaceae), from castor seed (Ricinus communis), and from plant isoprenoid feed stocks. We also use this method to compare the properties of these fluids with JP-8 and an earlier bio derived synthetic aviation kerosene made with reclaimed waste grease. We found that both the fuels derived from plant isoprenoids and from camelina vaporized at lower temperatures than did a typical JP-8 through the entire distillation curve. In contrast, the fuel derived from castor seed vaporized at higher temperatures than did the plant and camelina fuels, and also JP-8, through the entire curve. The distillation behavior of the plant isoprenoid fuel is most striking in that the distillation curve is rather more flat than the curve for a typical petroleum derived turbine fuel or for the alternatives we have examined. It is likely to be more suitable as a blending stock than a drop in replacement. More research will be needed to ensure that there would be no combustor operability issues as a result of the flat curve.

Quality of Some Nigerian Coals as Blending Stock in Metallurgical Coke Production

Two Nigerian coals, Lafia-Obi and Chikila were blended in the mass ratio of 70:30 with imported American and Polish coking coals. Proximate analysis, free swelling index, Ruhr dilatometer and Gieseler plastometer were used in assessing the coking qualities of both the single coals and the blends. The results show that the blends are lower in moisture and ash contents; higher in volatile matter and fixed carbon than the single Nigerian coals. The rheological parameters revealed superiority in thermo-plastic properties of the blends over the unblended local coals. Lafia-Obi/Foreign coals blends possess lower ash and better rheological properties compared to Chikila/Foreign coal composites which have high ash and poor rheological properties. These together suggest that amongst the two Nigerian coals, Lafia-Obi is superior for blending with the foreign ones in metallurgical coke production.

Increase of reformate yield by using polyacrylic acid as template in preparation of Pt/Re naphtha reforming catalysts

The need for naphtha reforming to produce high quality reformate for gasoline blend stocks with increased yield has become more urgent due to dwindling crude oil reserves and stringent air pollution regulations. Reforming catalysts prepared using polyacrylic acid (PAA) as a metal ion template exhibited 1.4–2.4% improvement in reformate yield and 1.0–2.0 wt% lower aromatic production compared to commercially available catalysts prepared using traditional metal salt coimpregnation methods, while maintaining a comparably high octane number. The catalyst prepared using the PAA template also showed higher liquid recovery with less coke deposition and longer projected catalyst lifetime. Characterization using infrared spectroscopy following the adsorption of CO revealed that catalysts made using the PAA method contained platinum particle surfaces with reduced atom coordination numbers.

Selective Additives for Improvement of Gasoline Octane Number

High octane blend base gasoline stocks are reformulated from 30% LSRN, 45% Reformate and 25% Powerformate on volume basis. ASTM standard and IROX 2000 analysis are performed to test blend stocks sample. Different additive types are used to improve octane number. These additives are tetraethyl lead, methylcyclopentadienyl manganese tricarbonyl; methyl alcohol, ethyl alcohol, iso-propanol, n-butanol, sec-butanol, tertiary butyl alcohol, tert-amyl alcohol, active amyl alcohol, iso-pentyl alcohol, isobutyl carbinol, benzol ,telone, xylene, amino benzene, N-N-dimethyl aniline, dimethyl ketone, and ethyl methyl ketone. Comparison is made between significant individual RON gains measured by standard CFR test-engine. The results indicated that the combined iso-propanol, oxinol (50/50 blend of methanol and TBA), aniline, and xylene with hydrocarbons fraction content in the gasoline base pool is better to ensure high RON. The results showed that a mixture of 20/54/10/16 of blend aniline/ iso-propanol/ oxinol/ xylene respectively, led to an increase in RON of gasoline blend pool from 84.5 to 96 RON, or 11.5% RON gain.

Butter as a Feedstock for Biodiesel Production

Fatty acid methyl esters (FAME) were produced from cow's milk (Bostaurus) butter by esterification/transesterification in the presence of methanol. The product was assayed according to the Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels (ASTM D 6751). The preparation failed to meet the specifications for flash point, free and total glycerin contents, total sulfur, and oxidation stability. Failures to meet the flash point and free/total glycerin specifications were determined to be due to interference with standard assays for these parameters by short-chain-length fatty acid esters. The oxidation stability of the butterfat FAME was improved by supplementation with a commercial antioxidant formulation. Approximately 725 ppm of antioxidant was required to meet the ASTM-specified stability value for biodiesel. This work indicates that, without further purification to reduce a slightly excessive sulfur content, fatty acid ester preparations produced from butter are unacceptable as sole components of a biodiesel fuel. However, it is possible that even without further purification a butter-based ester preparation could be mixed with biodiesel from other feedstocks to produce a blend that meets the current quality standards for biodiesel. The results presented here also illustrate some potential weaknesses in the accepted methods for biodiesel characterization when employed in the analysis of FAME preparations containing mid- and short-chain fatty acid esters.

Selective Additives for Improvement of Gasoline Octane Number

High octane blend base gasoline stocks are reformulated from 30% LSRN, 45% Reformate and 25% Powerformate on volume basis. ASTM standard and IROX 2000 analysis are performed to test blend stocks sample. Different additive types are used to improve octane number. These additives are tetraethyl lead, methylcyclopentadienyl manganese tricarbonyl; methyl alcohol, ethyl alcohol, iso-propanol, n-butanol, sec-butanol, tertiary butyl alcohol, tert-amyl alcohol, active amyl alcohol, iso-pentyl alcohol, isobutyl carbinol, benzol ,telone, xylene, amino benzene, N-N-dimethyl aniline, dimethyl ketone, and ethyl methyl ketone. Comparison is made between significant individual RON gains measured by standard CFR test-engine. The results indicated that the combined iso-propanol, oxinol (50/50 blend of methanol and TBA), aniline, and xylene with hydrocarbons fraction content in the gasoline base pool is better to ensure high RON. The results showed that a mixture of 20/54/10/16 of blend aniline/ iso-propanol/ oxinol/ xylene respectively, led to an increase in RON of gasoline blend pool from 84.5 to 96 RON, or 11.5% RON gain.

The Impact of Fischer–Tropsch Diesel on the Oxidation Stability of Biodiesel (FAME) Blends

Abstract Fischer–Tropsch (FT) distillates and first generation biodiesel are alternative fuels that can both be used directly as neat fuels in an internal combustion diesel engine or as blend stocks with conventional diesel fuel. Biodiesel is generally produced by the catalytic trans-esterification of triglycerides (vegetable oil) with methanol to form fatty acid methyl esters (FAME) and glycerol as a by-product. The FT process (or FT synthesis) is a catalyzed chemical reaction in which synthesis gas (syngas), a mixture of carbon monoxide and hydrogen, is converted into liquid hydrocarbons of various compositions. The oxidation and thermal stability of diesel fuel are very important properties since unstable diesel fuels can form soluble gums and or insoluble organic particulates that can clog the fuel filters and fuels system components. In the quest for increased efficiency of internal combustion compression ignition engines, the engines are increasingly downsized and turbo charged. These developments, together with the latest demands from modern injector systems, place a greater demand on the oxidative and thermal stability performance of a fuel due to the exposure of fuels to higher temperatures in comparison to historic engine and injector designs. Recirculation of heated fuel can also cause injector deposits originating from either gum or particulate formation. Biodiesel (FAME) and FT diesel have shown to be fully compatible as blend components with conventional crude derived diesel. FT diesel, produced from the low temperature FT (LTFT) process, generally has a lower density and viscosity and good cold flow properties. It is also a very stable fuel, which compensates for the high viscosity and density, poor cold flow properties, and unstable nature associated with biodiesel (FAME). This paper discusses the results obtained from a comparative study of the oxidation stability (using the Rancimat methodology) of FT (high temperature FT and LTFT) and petroleum diesel fuels, blended with up to 20 vol % of soya and rapeseed derived biodiesel (FAME).

Incompatibility of Fischer−Tropsch Diesel with Petroleum and Soybean Biodiesel Blends

The Department of Defense is the largest consumer of middle distillate fuels. It has been recommended that alternative fuel sources be considered as replacements or blending stocks for middle distillate ground transportation and marine fuels. Therefore, the search for suitable replacements or blending stocks is earnestly continuing. Renewable agricultural crops such as soybeans and others are now in the forefront. Nonrenewable synthetic fuels such as those produced by Fischer−Tropsch, FT, synthesis from coal and natural gas have been suggested. It is probable that several of these substitutes would be simultaneously blended into a middle distillate petroleum based diesel fuel. Care must be employed when blending fuels so that fuel specifications and storage stability are not decreased. This paper compares the storage stability of a three-part mixture consisting of Fischer−Tropsch diesel, a petroleum diesel, and a 5% and 10% soy biodiesel under ambient conditions.

SONOCHEMICAL SYNTHESIS OF BIODIESEL FROM CATFISH FAT

Biodiesel was prepared from catfish fat by alkaline-catalyzed transesterification with methanol. Using ultrasonic irradiation considerably sped up the transesterification and the phase separation as well as reduced by-product formation in the product in comparison with the heat-chemical method. The basis factors, such as content of catalysts, reaction time, dissolved time of catalyst in methanol, mol ratio of reactants, ultrasonic power, etc. were investigated and optimized. Biodiesel yield was more than 90%. Obtained biodiesel fuel was up to the Vietnamese standard for biodiesel fuel blend stock (B100).

Investigation of Enzyme-Catalyzed Transesterification of Used Frying Oils

Investigation of the possibility to convert used frying oils to less harmful but more valuable products is driven by the protection of environment and human health as well as economical reasons. One solution could be the conversion of these oils to transportation fuels and their application in Diesel engines in “pure” form or as blend stocks of diesel fuels. The conversion to biodiesel can be realized by transesterification with various catalysts. This paper presents the results of some experiments made by applying used frying oils and a process which is studied less intensively in the literature. The main goal of our experiments was to compare the transesterification efficiency of the three commercially available immobilized lipases [Candida antarctica (Novozym 435), Rhizomucor miehei (Lipozyme RM IM) and Thermomyces lanuginosus (Lipozyme TL IM)] which were applied under the same conditions and using the same feed. Based on our experimental results we established that we achieved the highest methyl ester content (£94%) approaching well the theoretical yield when we applied Candida antarctica (Novozym 435) among the investigated lipase enzymes.

Recent Inventions in Biodiesel Production and Processing- A Review

Since recent past the research on biodiesel production and processing has got high momentum as evidenced from the large number of publications and patents on the subject. Many novel and improved protocols based on chemical, physical, and biological approaches have been reported that addresses the critical issues related to biodiesel production, recovery, purification, and associated recovery of high valued secondary products. Biodiesel typically comprises lower alkyl fatty acid (chain length C14-C22) esters of short-chain alcohols, primarily, methanol or ethanol. Various methods, such as pyrolysis, micro-emulsification, ozonization, ultrasonication, and transesterification have been reported for the production of biodiesel from vegetable oil. Among these, transesterification is appeared as attractive and widely accepted technique. This transesterification is mostly done chemically or enzymatically using lipase as biocatalyst. Lipase catalysis has received increasing attention due to its certain advantages over the conventional chemical catalysis. However, poor operational stability and low focus on the application of lipase for the biodiesel production are some of the important obstructing factors that impede the progress of the enzyme-based process. In addition to the transesterification step, separation of the ester from the reaction mixture, purification of the ester and glycerol, maintenances of appropriate fuel quality standards of the biodiesel (or blend stocks) as per specification for the particular nation, storage and stabilization are ascribed as the critical steps having immense effect on the successful implementation of biodiesel production and processing. In this review the authors emphasise the important patents developed in the last few years that contribute to mitigate the major technological challenges on biodiesel production and processing.

Investigation of the production of high cetane number bio gas oil from pre-hydrogenated vegetable oils over Pt/HZSM-22/Al 2O 3

A new field of the catalytic application of Pt/HZSM-22/Al 2O 3 catalysts for the isomerization of pre-hydrogenated sunflower oils (PHSO) aiming the production of diesel fuel is presented. High cetane number blending components that are practically free of sulfur (<1 ppm) and of aromatic compounds are required for satisfying environmental and human health regulations as well as specifications of diesel fuels in the European Union (cetane number: min 51; CFPP: max −20 °C depending on the climate of the country). Experiments were carried out over catalysts containing 0.25–1.1% platinum on HZSM-22 at temperatures of 280–370 °C, total pressures of 35–80 bar; liquid hourly space velocities (LHSV) of 1.0–4.0 h −1, H 2 to hydrocarbon ratios of 250–400 Nm 3/m 3. Results indicated that the yield of liquid products obtained under favorable process conditions was >90%, the ratio of i-/n-paraffins was in the range of 3.7:1–4.7:1, cetane numbers were 81–84 units and CFPP values were between −18 and −14 °C. These are excellent blend stocks of diesel fuels.

Recycled Soybean Derived Cooking Oils as Blending Stocks for Middle Distillate Transportation Fuels

It has been proposed that biodiesel liquids be used as blending stocks for middle distillate ground transportation fuels by the Department of Defense. The U.S. Navy is considering allowing up to 20% biodiesel to be added as a blending stock to petroleum diesel fuels. It is important for operational consideration to look at the many problems this could present. Among the more important considerations are storage stability, filterability, fuel solubility, oxidative stability and induced instability reactions. This article reports on the use of recycled soybean derived fuel liquids. The fuel liquid was derived from recycled restaurant cooking oil with no added antioxidant after reprocessing. We compare this biodiesel in blends of both 10% and 20% with stable and unstable middle distillate fuels for storage stability, oxidative stability, solubility, and chemical instability results.

Recycled Soybean Cooking Oils As Blending Stocks for Diesel Fuels

It has been proposed that renewable energy sources be substituted or at least used as blending stocks for middle distillate ground transportation fuels. The U.S. Navy is considering allowing up to 20% soybean biodiesel to be added as a blending stock to petroleum diesel fuels. It is important for operational considerations to look at the many positives and/or negatives that this could engender. Among the more important considerations are storage stability, filterability, fuel solubility, oxidative stability, and induced instability reactions. This paper reports on methylated recycled restaurant soybean cooking oils used as blending stocks for ground transportation diesel fuels. We compare this recycled soy liquid in blends of both 10% and 20% with petroleum middle distillate fuels for storage stability, oxidative stability, solubility, and chemical instability results. These results are contrasted to those of pure soy-derived fuel liquids used as blending stocks.