Fuel Grade Ethanol Research Articles

Highly Efficient Production of Cellulosic Ethanol from Poplar Using an Optimal C6/C5 Co-Fermentation Strain of Saccharomyces cerevisiae.

Cellulosic ethanol is the key technology to alleviate the pressure of energy supply and climate change. However, the ethanol production process, which is close to industrial production and has a high saccharification rate and ethanol yield, still needs to be developed. This study demonstrates the effective conversion of poplar wood waste into fuel-grade ethanol. By employing a two-step pretreatment using sodium chlorite (SC)-dilute sulfuric acid (DSA), the raw material achieved a sugar conversion rate exceeding 85% of the theoretical value. Under optimized conditions, brewing yeast co-utilizing C6/C5 enabled a yield of 35 g/L ethanol from 10% solid loading delignified poplar hydrolysate. We increased the solid loading to enhance the final ethanol concentration and optimized both the hydrolysis and fermentation stages. With 20% solid loading delignified poplar hydrolysate, the final ethanol concentration reached 60 g/L, a 71.4% increase from the 10% solid loading. Our work incorporates the pretreatment, enzymatic hydrolysis, and fermentation stages to establish a simple, crude poplar waste fuel ethanol process, expanding the range of feedstocks for second-generation fuel ethanol production.

Waste Lignocellulosic Biomass as a Source for Bioethanol Production

Synthetically produced biofuels play a critical role in the energy transition away from fossil fuels. Biofuels could effectively lower greenhouse gas (GHG) emissions and contribute to better air quality. One of these biofuels is bioethanol, which could act as a gasoline replacement. For this purpose, a simulation of bioethanol production through lignocellulosic biomass fermentation, focused on distillation, was carried out in simulation software Aspen Plus. Since the possibility of absolute ethanol production through distillation is limited by the ethanol–water azeotrope, pressure swing distillation (PSD) was used to obtain fuel-grade ethanol (EtOH) with a fraction of 99.60 wt.%. The flowsheet was optimised with NQ analysis, which is a simple optimisation method for distillation columns. We found that the PSD has the potential to concentrate the EtOH to a desired value, while simultaneously removing other unwanted impurities whose presence is a consequence of pretreatment and fermentation processes.

Fatigue crack propagation of API 5L X70 steel in a modified simulated fuel-grade ethanol (MSFGE) environment

Fatigue crack propagation of API 5L X70 steel in a modified simulated fuel-grade ethanol (MSFGE) environment

An integrated sustainable bio-fuel and bio-energy supply chain: A novel approach based on DEMATEL and fuzzy-random robust flexible programming with [formula omitted] measure

The viability of the Indian government’s green initiative to blend 20% fuel grade ethanol with gasoline is investigated by modelling a sustainable integrated bio-fuel and bio-energy supply chain with multiple echelons in order to address the dual crisis of fossil fuels, i.e., environmental as well as gradually diminishing reserves. In order to find the best strategic and planning decisions, a multi-objective mixed integer programming model is developed that analyses the supply chain from a technological, economic, environmental, and social standpoints while handling various feedstocks, supply zones, products, and multiple periods. The drawbacks in addressing the uncertainty in the parameter as well as risk in decision making are overcome by introducing a novel fuzzy-random robust flexible programming approach based on Me measure and probabilistic programming. The presented model incorporates hybrid uncertainty, flexible constraints and a convex mixture of optimistic-pessimistic perspective of decision maker. A hybrid strategy combining the fuzzy Decision Making Trial and Evaluation Laboratory (DEMATEL) method and the multi-choice reference point goal programming with S-shaped utility function is presented to solve the generated multi-objective model. A case study in West Bengal, India is then performed that envisages the economic, environmental and social aspects of a bio-fuel and bio-energy supply chain.

Stress corrosion cracking in fuel-grade ethanol: The role of the testing methodology

The increase in fuel-grade ethanol (FGE) consumption demands efficient and safe storage and transportation. However, depending on the raw material used for ethanol production, stress corrosion cracking (SCC) might be a major concern. This work evaluated the API 5L X70 steel susceptibility to SCC in simulated fuel-grade ethanol (SFGE), corn, and sugar cane FGE. The maximum stress intensity factor (Kmax.) was determined from KR curves, and the stress intensity factor threshold for environment-assisted cracking (KEAC) was obtained from the direct current electric potential difference (DCEPD) versus load-line displacement (LLD) curves. The results showed that Kmax. was weakly affected by the environment (different variants of ethanol), although brittle fracture comprising cleavage-like features, intergranular facets, and secondary cracks was observed for SFGE and corn FGE. Under the specific set of testing conditions adopted here, the parameter KEAC was effective in showing that the API 5L X70 steel is quite sensitive to SCC in SFGE and corn FGE, and not susceptible to this progressive cracking process in sugar cane FGE.

Optimized Sieving Effect for Ethanol/Water Separation by Ultramicroporous MOFs.

High-purity ethanol is a promising renewable energy resource, however separating ethanol from trace amount of water is extremely challenging. Herein, two ultramicroporous MOFs (UTSA-280 and Co-squarate) were used as adsorbents. A prominent water adsorption and a negligible ethanol adsorption identify perfect sieving effect on both MOFs. Co-squarate exhibits a surprising water adsorption capacity at low pressure that surpassing the reported MOFs. Single crystal X-ray diffraction and theoretical calculations reveal that such prominent performance of Co-squarate derives from the optimized sieving effect through pore structure adjustment. Co-squarate with larger rhombohedral channel is suitable for zigzag water location, resulting in reinforced guest-guest and guest-framework interactions. Ultrapure ethanol (99.9 %) can be obtained directly by ethanol/water mixed vapor breaking through the columns packed with Co-squarate, contributing to a potential for fuel-grade ethanol purification.

Durable composites by vulcanization of oleyl-esterified lignin.

Productive utilization of lignocellulosic biomass is critical to the continued advancement of human civilization. Whereas the cellulose component can be efficiently upconverted to automotive fuel-grade ethanol, the lack of upconversion methods for the lignin component constitutes one of the grand challenges facing science. Lignin is an attractive feedstock for structural applications, in which its highly-crosslinked architecture can endow composite structures with high strengths. Prior work suggests that high-strength composites can be prepared by the reaction of olefin-modified lignin with sulfur. Those studies were limited to ≤5 wt% lignin, due to phase-separation of hydrophilic lignin from hydrophobic sulfur matrices. Herein we report a protocol to increase lignin hydrophobicity and thus its incorporation into sulfur-rich materials. This improvement is affected by esterifying lignin with oleic acid prior to its reaction with sulfur. This approach allowed preparation of esterified lignin-sulfur (ELS) composites comprising up to 20 wt% lignin. Two reaction temperatures were employed such that the reaction of ELS with sulfur at 180 °C would only produce S-C bonds at olefinic sites, whereas the reaction at 230 °C would produce C-S bonds at both olefin and aryl sites. Mechanistic analyses and microstructural characterization elucidated two ELS composites having compressive strength values (>20 MPa), exceeding the values observed with ordinary Portland cements. Consequently, this new method represents a way to improve lignin utilization to produce durable composites that represent sustainable alternatives to Portland cements.

DFT Analysis of Ethanol Electro-Oxidation on Fe(110) and Fe3c(110) and Its Correlation with the Stress Corrosion Cracking of Carbon Steel

Stress Corrosion Cracking (SCC) of carbon steel in fuel-grade ethanol is typically intergranular in service, but it is nearly always transgranular, in short-term laboratory experiments. While this might be considered an inconvenience, it provides an important clue about the SCC mechanism. The important point is that the transgranular cracking occurs under much milder mechanical conditions than any known form of hydrogen embrittlement in ordinary carbon steel. For this and other reasons, hydrogen is not considered to be the cause of this form of SCC. Transgranular SCC of carbon steel occurs in a very particular set of environments. Anhydrous liquid ammonia, anhydrous ammonia-methanol and CO-CO2-H2O are the key systems to be considered, apart from alcohols. High-temperature water containing oxygen also causes transgranular SCC, but is a less severe environment, probably because a magnetite film imposes a compressive stress that partially opposes any embrittlement effect. In our view, the important factor connecting these examples is embrittlement by interstitials. Just as hydrogen can embrittle iron, so can nitrogen or carbon (or oxygen). The main distinction is the diffusivity of the interstitial in iron. Ammonia can be oxidized to N, and CO can be reduced to C (or, in the language of surface chemistry, this could be dissociative adsorption). Still, at ambient temperature, those interstitials can only diffuse a few nm in relevant times of seconds. But we know little about the effect of such near-surface embrittlement on the propagation of a crack, and research on such surface effects is very important. Striking mechanical and morphological similarities of the SCC of carbon steel in ethanolic media with those governed by a cleavage-like mechanism in CO-CO2 aqueous solutions prompted the investigation of the possibility of ethanol electrochemical oxidation into CO on ferrite (Fe) and cementite (Fe3C) surfaces. Density functional theory computations on (110) surfaces revealed that the catalytic activity of Fe and Fe3C through the α dehydrogenation pathway can significantly reduce the energy barrier of electro-oxidation of ethanol and production of CO to 0.575 and 0.480 eV, respectively. These first principle calculations indicate that at the anodic potentials applied during potentiostatic slow strain rate testing, ethanol electro-oxidation to CO is thermodynamically viable on carbon steel, giving further credit to the involvement of cleavage type SCC of carbon steel in ethanolic environments.

Key prospects and major development of hydrogen and bioethanol production

Cheap Production of bioethanol from renewable lignocellulosic waste has the imperative potential to economically cut burgeoning world dependency on fossils while reducing net emission of carbon dioxide (CO2), a principal greenhouse gas (GHGs). This paper highlights key benefits and status of bioethanol production technologies, aiming mainly on recent developments and its key potentials in Pakistan. Most sector of Pakistan economy heavily rely on the energy and power that is being produced using traditional approaches like from oil and hydel. However, the sedimentation in dams cut-down the energy generation and overwhelmed severe energy crisis that are witnessed since last decade. Thus, Pakistan must go to avail alternative sources of energy like hydro, biomass and solar so that energy security can be ensured to recover the tremendous loss of economy. Renewable biomass is abundantly available in Pakistan which can be used to produce bioethanol and electricity. Currently, 22 distilleries are producing the ethanol from sugar cane bagasse and out of these only 8 distillation units are producing motor fuel grade ethanol. The current bioethanol production of country is about 403,500 tons/year along with 2423 tons of biodegradable waste available in major cities. In addition, Pakistan produces 6.57, 0.5, 0.66, and 2.66 million tons of sugarcane, corn, rice, and wheat straw per annum, respectively. This biomass can produce 1.6 million liters of bioethanol which can produce approximately 38% of Pakistan's electricity annually. Despite having large potential, Pakistan is still producing a few volumes of ethanol from sugarcane bagasse. The production of bioethanol can be boosted using (I) pretreatment of agricultural biomass by alkali (II) enzymatic and bacteria-based hydrolysis of the biomass (III) post-hydrolysis using pressurized steam above 100 °C (IV) Fermentation of the biomass@ 7–10 h and (V) and (VI) distillation of bioethanol. This study recommends (1) increase R&D capacities mainly in the west and central regions of Pakistan, (2) initiate mega-projects to promote integrated bio-ethanol production at agriculture farms by providing 1/3 subsides, (3) purchase of bioethanol directly from the major agricultural farms, (4) produce bioethanol related manpower from the key research institutes as specified in this study.

Estimating biofuel contaminant concentration from 4D ERT with mixing models

We present the results of a lab-scaled feasibility study to assess the performance of electrical resistivity tomography for detection, characterization, and monitoring of fuel grade ethanol releases to the subsurface. Further, we attempt to determine the concentration distribution of the ethanol from the electrical resistivity tomography data using mixing-models. Ethanol is a renewable fuel source as well as an oxygenate fuel additive currently used to replace the known carcinogen methyl tert-butyl ether; however, ethanol is preferentially biodegraded and a cosolvent. When introduced to areas previously impacted by nonethanol-based fuels, it will facilitate the persistence of carcinogenic fuel compounds like benzene and ethylbenzene, as well as remobilize them to the ground water. These compounds would otherwise be retained in the soil column undergoing active or passive remediation processes such as soil vapor extraction or natural attenuation. Here, we introduce ethanol to a saturated Ottawa sand in a tank instrumented for four-dimensional geoelectrical measurements. Forward model results suggest pure phase ethanol released into a water saturated silica sand should present a detectable target for electrical resistivity tomography relative to a saturated silica sand only. We observe the introduction of ethanol to the closed hydraulic system and subsequent migration over the duration of the experiment. One-dimensional and three–dimensional temporal data are assessed for the detection, characterization, and monitoring of the ethanol release. Results suggest one-dimensional geoelectrical measurements may be useful for monitoring a release, while three-dimensional geoelectrical field imaging would be useful to characterize, monitor, and design effective remediation approaches for an ethanol release, assuming field conditions do not preclude the application of geoelectrical methods. We then attempt to use predictive mixing models to calculate the distribution of ethanol concentration within the measurement domain. For this study we examine four different models: a nested parallel mixing model, a nested cubic mixing model, the complex refractive index model (CRIM), and the Lichtenecker-Rother (L-R) model. The L-R model, modified to include an electrical formation factor geometry term, provided the best agreement with expected EtOH concentrations.

Sensitivity Analysis of Bioethanol Simulation from Microalgae with Pressure Swing Distillation Process

Energy is an important parameter in the social and economic development of a country. Thus, it is necessary to seek renewable energy to supply energy needs in Indonesia. The production of bioethanol from microalgae as a biofuel is one way to reduce the use of fossil fuels. Microalgae has an advantage over other types of biomass sources due to its high biomass productivity and do not compete with agricultural crops for land and water resources. In the bioethanol production process, the ethanol and water form an azeotrope mixture of 95.6% of ethanol at 1 atm and 78.15°C. The objective of this research was to analyse and determine the operating conditions and the optimum distillation column configuration which results in high ethanol purity according to fuel specifications (fuel grade ethanol). The method of pressure-swing distillation was applied to separate the azeotrope of ethanol-water and obtain high purity ethanol. A simulation model of bioethanol production with pressure-swing distillation system was conducted by using Aspen Plus V10. In this research, the influence of process parameters such as distillation column pressure, reflux ratio, feed stage location, and the number of theoretical stages was analysed by using model analysis tools. The results showed that the obtained bioethanol purity of 99.9% with the condenser and reboiler duty of the LP column -79.931 kW and 667.651 kW, respectively; while the HP column is -47.627 kW and 57.698 kW.

Efficient purification of bioethanol by an ethanol-trapping coordination network

Bioethanol is an essential energy source and is produced from agricultural feedstocks. However, raw bioethanol contains much water and methanol, and the traditional distillation approach has hardly removed it. Adsorptive separation of ethanol from water and methanol by adsorbents is an energy-efficient and promising method to produce fuel-grade ethanol. In this work, by regulating the pore surface in a new coordination network, [Cd(4-pmntd)(tpa)] (4-pmntd = N,N’-Bis(4-pyridymethy) naphthalene diimide; tpa = terephthalic acid), we target ultrahigh ethanol uptake and efficient ethanol/water separation, surpassing most benchmark materials. Explicitly, the ethanol uptake of Cd(4-pmntd)(tpa) (62.5 wt% at 100 kPa and 298 K) has the second-highest adsorption capacity among all the metal–organic frameworks (MOFs). In addition, Cd(4-pmntd)(tpa) gives ethanol/water selectivity of 32 toward a mixture of ethanol and water. Dynamic breakthrough measurements confirmed the excellent separation of ethanol and water. Under different ethanol/water ratios, Cd(4-pmntd)(tpa) extracts a low ethanol concentration from an ethanol/water mixture and produces ethanol in 99.1% purity in one step. Spectroscopic measurement and grand canonical Monte Carlo (GCMC) simulations provide critical insight into the adsorption/separation mechanism. The framework can form rich intermolecular C-Hguest…πhost, C-Hguest…Ohost and C-Hhost…Oguest interactions with ethanol molecules because of the suitable pore size and pore surface set in Cd(4-pmntd)(tpa). Thus, the adsorption enthalpies for ethanol in Cd(4-pmntd)(tpa) reached 66.16 kJ/mol, but only 29.44 kJ/mol and 49.21 kJ/mol for water and methanol, respectively. Moreover, the porous material exhibits good stability and can be easily combined with chitosan to form filter film, which is vital for potential industrial applications.

Effect of cellulose crystallinity modification by starch gel treatment for improvement in ethanol fermentation rate by non-GM yeast cell factories

This paper studies the reduction of crystallinity degree (CD) of cellulose treated with starch gel (SG), and the correlation of CD with the fermentation efficiency of cellulose to fuel-grade ethanol. Cellulose bioconversion from wood sawdust, consisting of three processes, was conducted in the same batch (one-step). The XRD and TEM analysis revealed 11% reduction in cellulose CD after its treatment with SG. One-step bioconversion process was performed employing two cell factories (CF) of non-engineered S. cerevisiae. CFs contained non- engineered S. cerevisiae cells covered with either SG entrapping Trichoderma reesei or cellulases prepared in the laboratory and immobilized in SG. The consolidated fermentation of treated cellulose resulted in an increase of bioethanol concentration (60-90%) in 2-day fermentation and the maximum ethanol concentration reached was approximately 5mL/L (3.95g/L). The fermentation efficiency for grade-fuel ethanol production was improved by cellulose pretreatment using SG to achieve reduced CD.

Biosynthesis of fuel-grade ethanol from cellobiose by a cell-factory of non-GMO Saccharomyces cerevisiae/starch-gel-cellulase

The aim of this work was to ferment cellobiose to fuel-grade ethanol in one-step bioconversion employing a cell-factory (CF) of non-Genetically Modified Organism (non-GMO) Saccharomyces cerevisiae. The proposed technology involved the production of a freeze-dried preparation of CF of non-GMO S. cerevisiae covered by a layer of starch-gel (SG) containing cellulase enzyme. Parameters studied for one-step bioconversion of cellobiose to ethanol included temperature (33–40 °C), cellobiose concentration (70–150 g/L), and cellulase activity (60–150 FPU/g). High conversion (90%) of cellobiose in a 48 h one-step process was achieved using 70 g/L cellobiose, 150 FPU/g at 30 °C, indicating the efficiency of CF. S. cerevisiae in CF were also capable to ferment at 40 °C with the major role of enzyme activity and cellobiose concentration in fermentation. In our studies, the ethanol yield and conversion of cellobiose were found competitive, with other processes reported with S. cerevisiae as GMO and enzyme co-immobilized in alginates beads. Consequently, the results revealed a new concept for bio-ethanol production from cellobiose in one-step simultaneous-hydrolysis-fermentation (OSHF), which could be a precursor study for large-scale cellulose bioconversion for fuel-grade alcohol production.

A comparative study on the corrosion behaviour of welded and un-welded API 5L X70 steel in simulated fuel grade ethanol

A comparative study on the corrosion behaviour of welded and un-welded API 5L X70 steel in simulated fuel grade ethanol

Distillation-Adsorption of Bioethanol Using Natural Kaolin

Bioethanol has been known as one of the alternative energy sources to replace petroleum. The use of bioethanol as a fuel has requirements that must meet fuel standards or refer to as Fuel Grade Ethanol (FGE). Further refining is required to achieve this qualification. The distillation method is the most commonly used method in bioethanol purification, but the results are less than optimal and sometimes the ethanol produced will be more volatile. Distillation-adsorption method using clay-based materials was developed to solve this problem. The purpose of this study is to purify bioethanol and determine the physical characteristics of the bioethanol produced and to assess the % purity of bioethanol from adsorption distillation. Characterization of activated natural kaolin as adsorbent, determination of the optimum contact time in the distillation-adsorption process, determination of the optimum mass of kaolin used and determination of the physical properties of bioethanol have been carried out. The results showed that 1 hour adsorption distillation could increase the ethanol content from 7.9% to 29.33%. In the study of the effect of the mass of kaolin, the optimum result was 25.25% ethanol using a mass of 5 grams. physical properties test of bioethanol obtained a density of 0.8211 gr/cm3 and a viscosity of 2.096 cps.

Last synthetic ethanol plant in US to close

The petrochemical giant LyondellBasell Industries will exit the synthetic ethanol business—one of its longest-standing operations—by the end of October. The company is closing its ethanol plant in Tuscola, Illinois, where it makes the alcohol for industrial applications via the hydration of ethylene. It is the last synthetic ethanol plant in the US. The firm is also closing a plant in Newark, New Jersey, where it makes denatured ethanol. About 100 employees in Tuscola and 5 in Newark will be affected. LyondellBasell says that in recent years synthetic ethanol has struggled against the fermentation-based competition, much of which is used as fuel. “Long-range profitability is impacted due to an oversupply of fuel-grade ethanol and falling price premiums,” a LyondellBasell spokeswoman says. According to the Nebraska Department of Environment and Energy, the price of fuel-grade ethanol averaged $0.62 per L in 2014 and had fallen to $0.23 per L by 2020. Scott

Review on technologies to separate and purify ethyl alcohol from dilute aqueous solutions

Abstract Ethyl alcohol (ethanol) is viewed upon as a fuel additive or even as an alternative fuel. Fermentation is used to produce dilute (<20 mass%) ethanol. This is needed to be concentrated to almost anhydrous, fuel grade ethanol (>99.5 mass%). The technologies used for concentration from dilute grade to fuel grade ethanol are summarized in this review. Thus, extraction; distillation; use of membranes; adsorption and some miscellaneous methods are discussed in detail. For each technique, the inlet and outlet concentrations; merits and demerits and scope for future work are indicated. Hybrid separations are discussed. In addition to technical feasibility, economic viability of the techniques is also discussed. A brief discussion on current industrial practice is also presented.

Bioethanol prospect from agricultural crops and its biomass in Indonesia

Contradiction between the surplus domestic bioethanol supply and the failure to fulfill the bioethanol E2 biofuel program in 2020 is because the fuel grade ethanol price is still more expensive than gasoline. Indonesia’s fuel consumption needs, especially gasoline is increased from 37.49 million kL in 2020 to 43.59 million kL in 2025, with a deficit that is met with gasoline imports. Bioethanol production is still in surplus, the remainder is exported, still unable to supply the E2 bioethanol program and the import of non-fuel-grade ethanol is carried out. The abundance of mollase is not only the main raw material for bioethanol, but it is in competition with other industries such as MSG, and the decline in sugar cane land will reduce the availability of mollase in the future. In 2015, world bioethanol produces 1,390 million liter from 2G bioethanol, still in TRL4~TRL8 status, yet to commercial. To maintain ethanol supply security, potential biomass and waste-crops, and a lot of available sources that are not in competition with food needs, technological aspects, productivity, availability, and other aspects, biomass commodities need to continue to be developed with more intensive collaboration between institutions (academic, government, private). This study assesses the greatest potential of non-food biomass in Indonesia, including the 2nd generation bioethanol, 3rd generation, and the current biggest challenge in the readiness and maturity of the technology and its economic feasibility.

Fuel Property Investigation: Jatropha Biodiesel, Used Cooking Oil Biodiesel and Fuel-grade Ethanol Blends

Compression ignition (CI) engines are one of the promising power producing units which provide higher efficiency and durability. Increasing environmental pollution and depleting resources led the research in the field of alternative fuels such as biodiesels, ethanol etc. for utilization in CI engines. In the present study, two different types of biodiesels i.e. Jatropha Biodiesel (JBD), Used Cooking Oil (UCO) Biodiesel and Ethanol were investigated for the fuel properties and compared. Various fuel properties like density, kinematic viscosity, calorific value, oxidation stability, cold weather properties (CFPP, CF, and PP), and flash point temperature were measured and compared for pure form of alternative fuels. Different blends (5%, 10%, 15% and 20%) of JBD, UCO biodiesel and ethanol were also investigated. It has been observed that ethanol showed lower density, lower viscosity and superior cold weather properties compared to the tested fuels/blends. The average viscosity for ethanol was measured to be 1.08 mm2/sec which is ∼61.8 % less compared to mineral diesel. Oxidation stability tests were also performed where mineral diesel shows 83.15 min for 10% pressure drop at 140°C and 700 kPa, UCO biodiesel and JBD shows 9.2 min and 8.32 min. 5% ethanol blend showed sharp reduction in flash point compared to mineral diesel, however, it remained almost at the same level with further blending.