Biobutanol Research Articles

Impact of diesel/renewable fuels blend on gaseous and particle emissions of a light-duty vehicle under real driving emissions

In this study, the environmental impact of Bio-butanol (BB) and Hydrotreated Vegetable Oil (HVO) use, each blended with diesel fuel, was investigated. To this aim, pollutant emissions were measured at the exhaust of an Euro 5 commercial light-duty vehicle, fueled with diesel, BB/diesel blend (10 %v BB) and HVO/diesel blend (15 %v HVO). The experimental activity was realized by performing Real Driving Emission (RDE) tests in Napoli (Italy), which allowed to measure total hydrocarbons (THC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOX), and particle emissions during the real use of vehicle by using a portable emission measurement systems (PEMS). The results show that the differences between fuels are small and not statistically significant for all emission parameters. CO and THC emissions increase with the renewable fuel blends, mainly with the BB blend in the urban environment due to the increasing of cold start contribution. NOX emissions increased with BB (by approximately 4 %) and decreased with the HVO (by approximately 13 %). With both renewable fuel blends, particle emissions at engine output were reduced by 25 %–41 % and fuel consumption by 6 %–10 % compared with diesel.

Comparative Study of Combustion, Performance and Emission Characteristics of Hydrotreated Vegetable Oil–Biobutanol Fuel Blends and Diesel Fuel on a CI Engine

This article is a study of Hydrotreated Vegetable Oil and Butanol Fuel blends, which are mixed in three different proportions (HVOB5, HVOB10 and HVOB20), and the comparison of their combustion (in-cylinder pressure, pressure rise and ROHR), performance (fuel consumption, BSFC and BTE) and emission (CO2, NOX, HC and Smoke) characteristics with those of fossil diesel fuel. In the wake of finding an alternative fuel that requires little to zero modifications to the existing IC engines, it is necessary to account for the necessity of matching the efficiency of conventional fuels as well as greatly reducing its exhaust emissions. As a result of transesterification, HVO is found to have better stability and higher CN compared to other biofuels. It is termed a “renewable diesel” due to its ability to reduce emissions while maintaining efficiency. HVO as a fuel has higher cost efficiency, and for a more stable oxygen content in the fuel, an alcohol substitute is needed. Butanol, which has a considerable advantage over other alcohols due to its higher density, viscosity and CN, is selected. HVOB5 and HVOB10 are found to match diesel fuel in terms of fuel consumption while having a ~1% lesser efficiency. In terms of emissions, all the fuel mixtures including HVO100 are found to have ~4–5% lesser CO2, ~10–15% lesser NOX and a ~25–45% reduction in smoke levels.

Chemical and Sooting Structures of Counterflow Diffusion Flames of Butanol Isomers: An Experimental and Modeling Study

ABSTRACT This work reports an experimental and numerical analysis on the sooting characteristics of butanol isomers. Light extinction and gas chromatography were used to measure soot and gas-phase species, respectively. Kinetic analysis of the tested flames was performed with detailed gas-phase mechanism and a sectional soot model. The present work aims to provide an understanding on the effects of butanol isomeric structures on sooting tendencies. For a comprehensive analysis, flames of both neat butanol fuels and butanol/hydrocarbon mixtures were studied. The results showed that the relative ranking of sooting tendencies among the butanol isomers were similar in neat butanol flames and in butanol-doped ethylene flames. In addition, we show that a small amount of butanol addition in ethylene flame enhanced soot formation. It was found that different isomeric structures mainly affected the formation of C3H3, which led to the different concentrations of important aromatic soot precursors. In the butanol-doped ethylene flames, the blending of the four butanol isomers increased the number of C3H3 formation pathways, which in turn significantly increased the production of benzene. Structural effects explaining for the differences in the sooting tendencies of the four butanol isomers in neat butanol flames and ethylene/butanol flames were found to be the same.

Lignocellulose Pretreatment by Deep Eutectic Solvents for Biobutanol production

Lignocellulose Pretreatment by Deep Eutectic Solvents for Biobutanol production

Biobutanol maker is shutting down

Biobutanol maker is shutting down

Study of the Integrated Product Recovery by Gas Stripping for the Abe Fermentation with a Fed-batch Fermenter

Because of the growing demand for renewable fuels, the production of butanol through acetone-butanol-ethanol (ABE) fermentation of lignocellulosic biomasses has been recently attracting an increasing research interest.The major limit for an industrial-scale production of bio-butanol is the high separation cost, due to the presence of other fermentation products and to its low final concentration in the broth. In fact, the microorganism used in the ABE fermentation suffers from product inhibition leading to a low ABE final concentration in a batch process. The application of an integrated product recovery technique able to remove butanol during fermentation is a viable solution to solve the problem and to improve the economics of the ABE fermentation.In this context, gas stripping has been proven to be an effective separation technique, able to reduce the inhibition of the microorganism and, therefore, to increase the process productivity.However, gas stripping usually removes a large amount of water together with butanol and requires a higher energy input, because of its lower butanol selectivity, in comparison with other separation techniques. To improve the performances of the integrated fermentation-gas stripping process for butanol production, optimization of gas stripping and fermenter conditions, and a better understanding of its effects on the ABE fermentation is needed.This study deals with the synthesis of a process configuration for the integrated recovery of butanol from a fermentation unit operated in a fed-batch mode, in which the product is recovered from the fermentation broth by means of nitrogen gas stripping and is, subsequently, fractionated in a distillation train. For the studied configuration, a detailed simulation of the integrated recovery process including the fed-batch fermenter and the downstream separation train has been performed. The simulation results have been used to evaluate the effect of the integrated product recovery on the process productivity and on the total energy consumption, which has been quantified through the net equivalent fuel approach. Finally, the performances of the integrated process have been compared with the ones obtained with a traditional batch fermentation, in order to assess the potential of the proposed process solution.

A Novel Process Design for Biobutanol Purification from ABE Fermentation

The decrease in the oil supply and increasing environmental concerns boost the demand for alternative biofuels. In this context, biobutanol production from acetone-butanol-ethanol (ABE) fermentation comes forward as a remarkable process alternative. The main drawback of this alternative is the production of dilute fermentation broth which results in very energy demanding separation steps. Thus, several hybrid separation techniques have been studied combining extraction and distillation technologies to develop energy efficient separation processes. However, these techniques bring their own disadvantages, while they are solving the well-known drawbacks. In this study, a novel process including reactive distillation columns is proposed to purify biobutanol from acetone-butanol-ethanol (ABE) fermentation. The results indicate that there is a significant decrease in the reboiler heat duties. In addition, a co-product (ethylene glycol) is obtained as the result of the reaction taking place in the process besides the purification of butanol, ethanol and acetone.

Biobutanol: New era of biofuels

Biobutanol: New era of biofuels

Assessment of Hybrid Processes for Bio-Butanol Purification Applying Process Simulation

Bio-butanol production based on ABE (acetone-butanol-ethanol) fermentation is facing increasing interest as a transport fuel, since it offers significant advantages to other bio-fuels. However, to ensure an economic operation two bottlenecks has to be overcome: (1) high cost of the fermentation substrate, and (2) high energy demand for butanol purification via distillation due to low solvent concentration in fermentation broth. While first bottleneck might be overcome by the use of alternative feedstock like lignocelluloses or agro-food-wastes, the latter can be targeted by introducing hybrid purification concepts, combining in-situ removal techniques with distillation. Experimental and literature data based on lab-scale size experiments operated with synthetical fermentation broth are used to parameterize an Aspen Plus® simulation to predict the energy demand for bio-butanol purification for three in-situ removal techniques coupled with distillation and to compare to a standalone distillation sequence: gas stripping, pervaporation and adsorption/desorption. Depending on the initial solvent content of fermentation broth, with 23.2 - 31.2 MJ/kg butanol the heat demand of the standalone distillation sequence is slightly below the energy content of butanol of about 36 MJ/kg. Applying gas-stripping and pervaporation before purification via distillation reduces the heat demand by 50 % to 13.6 - 16.8 MJ/kg and 12.0 - 14.5 MJ/kg butanol, respectively. Best result is shown by combining adsorption and distillation with an energy demand of 5.0 – 5.7 MJ/kg butanol. However, the advantageous low overall energy demand results from low efforts in the distillation step, only considering separation of butanol and water, but neglecting purification of acetone and ethanol obtained in ABE fermentation.

Investigation of Process Alternatives for the Separation of Ethanol, N-Butanol and Water Ternary Mixture

Biofuel production is an ever current topic, as bioethanol and biobutanol have a great potential to partially or completely replace fossil fuels in the automotive industry due to their attractive characteristics. They are usually produced by fermentation resulting in a highly diluted mixture, which poses a challenge to the downstream processing and the production of pure alcohols.In the course of this work, conventional separation systems of simple, extractive and heteroazeotropic distillation are compared with hybrid distillation-pervaporation systems for the separation of a ternary ethanol-n-butanol-water (EBW) mixture. Pervaporation (PV) is studied as an option for the final dehydration of the alcohol-water mixtures due to its great industrial potential in the separation of azeotropes. Simulations are carried out in ChemCAD® flowsheeting software, and the process alternatives are evaluated in an economic point of view, revealing the potentials and drawbacks of PV in a complex separation task.

Theoretical Study of the Effects of Spark Timing on the Performance and Emissions of a Light-Duty Spark Ignited Engine Running under Either Gasoline or Ethanol or Butanol Fuel Operating Modes

Much research is ongoing to find suitable alternate fuels in order to reduce the exhaust emission levels without deteriorating the basic performance characteristics of conventional spark-ignited (SI) engines. One of the methods to achieve the above problem is the use of alcohols as full supplement fuels to normal gasoline. At the same time, many related research studies have shown that the use of alcohols has a negative impact on some basic engine performance characteristics, e.g., brake power output, etc. On the other hand, spark timing is one of the critical engine operating parameters that significantly influences the combustion mechanism inside the combustion chamber of a SI engine. Therefore, the primary objective of the present work is to investigate the effect of spark timing on the performance and emissions characteristics of a conventional, four-stroke, SI engine running under three different fuel operating modes, viz. with conventional gasoline or ethanol or butanol. The specific investigation is conducted by using an in-house, comprehensive, two-zone phenomenological model. The predictive ability of the model is tested against pertinent experimental data and it is found that the computed results are in good agreement with the respective experimental ones. For all test cases examined herein, the results concern basic engine performance characteristics, i.e., cylinder pressure, power output, specific fuel consumption etc., as well as NO and CO emissions. The main objectives of the work were to record and evaluate the impact that spark timing has on the performance characteristics and emitted pollutants of a conventional SI engine, operating under either conventional gasoline or ethanol or butanol fuel operating modes. Moreover, it deals with the determination of an optimum combination between the type of fuel used and the spark timing, so that probable undesirable effects on engine performance characteristics would be avoided. By comparing this investigation results, it is revealed that the use of alcohols as a full substitute fuel of gasoline accompanied with an appropriate alteration of the spark timing, could be a promising solution to improving both the efficiency and environmental behavior of a light-duty, spark-ignited (SI) engine, without causing any harmful problems to the engine operational lifetime. The conclusions from the study may prove valuable for the application of this technological solution to existing conventional SI engines.

Prediction and optimization of hydrogen yield and energy conversion efficiency in a non-catalytic filtration combustion reactor for jet A and butanol fuels

Hydrogen production is one of main subjects in fuel cells. The traditional method of synthesis gas production is based on fuel reforming using catalysts. The main problem of these methods is sensitivity and fast degradation of catalysts especially when fuels with high sulfur content are used. A new technique for hydrogen production is fuel-reforming using non-catalytic filtration combustion in porous media reactors. Various experimental works have been carried out to increase hydrogen production under different operating conditions such as inlet fuel velocity and equivalence ratio. First, we investigated the ability of adaptive neuro fuzzy inference system (ANFIS) for predicting the filtration combustion characteristics. Four distinct ANFIS models were developed for estimating the hydrogen yield and energy conversion efficiency for fuels of jet A and butanol. Eight different membership functions of dsigmf, gauss2mf, gaussmf, gbellmf, pimf, psigmf, trapmf and trimf were tested for training of the ANFIS networks. The results showed that the RMSE of the best developed ANFIS models for estimating of the hydrogen yield of jet fuel, hydrogen yield of butanol, conversion efficiency of jet fuel and conversion efficiency of butanol were 1.399, 1.213, 0.508 and 2.191, respectively. Moreover the R2 values of 0.998, 0.998, 0.999 and 0.999 were obtained for predicting the above mentioned variables, respectively. In the second step, a novel algorithm based on imperialist competitive algorithm (ICA) was used for optimization of hydrogen yield and energy efficiency. The maximum value of hydrogen yield and energy efficiency was 50.46% and 67.88% for jet A and 47.27% and 96.93% for butanol, respectively. The results showed that the imperialist competitive algorithm is an efficient and powerful algorithm to optimize combustion processes.

Inherent Occupational Health Assessment of Biobutanol Separation Processes During the Conceptual Design Stage

Occupational health assessment on chemical processes is a crucial step in the workplace management system. Constant exposure towards harmful chemical substances can be detrimental to worker’s health and the resulting medical compensation is often costly. Despite this, health performance of chemical processes was often being neglected as compared to safety and environment, and the assessment, upon conducted, was usually not carried out comprehensively. To bridge this existing gap, occupational health hazards assessment was conducted on biobutanol separation process - a biomass-based fuel that has the potential in replacing fossil fuel as the source of energy. For this, a method called the Inherent Occupational Health Index (IOHI) was used to assess eight biobutanol separation processes during the conceptual design stage. Chemical substances involved in the processes were evaluated based on their operating conditions, physical and chemical properties. Each of these elements was assigned with penalties depending on the degree of the potential health hazard they may pose. Based on the cumulative hazard level, the processes were ranked by the healthiness level. Following the assessment, the appropriate counter measures to reduce the hazards were then proposed.

Impact of oxygenated additives to diesel-biodiesel blends in the context of performance and emissions characteristics of a CI engine

Butanol is receiving huge interest in the area of alternative fuel in the compression ignition (CI) engines. In this work, butanol is used as an oxygenated additive to diesel and biodiesel blend fuels to evaluate the performance and emission of CI engine. The commercially available pure diesel fuel (D100) and 80% commercially available diesel- biodiesel bled (5% biodiesel and 95% by volume) and 20% butanol (BU20) fuels were investigated to evaluate the effects of the fuel blends on the performance and exhaust emissions of a single cylinder diesel engine. The experiment was conducted at fixed load of 75% with the five engine speeds (from 1200-2400 rpm with an interval of 300 rpm). The engine performance parameters such as power, torque, fuel consumption and thermal efficiency and exhaust gas emissions such as nitrogen oxides, carbon monoxide, and exhaust gas temperature were analysed from the experimental data. The results shows that although butanol addition has caused a slight reduction in power and torque values (11.1% and 3.5%, respectively), the emission values of the engine were improved. With respect to the exhaust gas temperature, CO and NOx emissions, of BU20 is reported to have reduction by 17.7%, 20% and 3%, respectively than the B100. Therefore, butanol can be used as a fuel additive to diesel-biodiesel blends.

Modulation of integral length scales of turbulence in an optical SI engine by direct injection of gasoline, iso-octane, ethanol and butanol fuels

In-cylinder air flow structures are known to play a major role in mixture preparation and engine operating limits for spark-ignition engines. In this paper PIV measurements were undertaken in an optical spark-ignition at 1500RPM, part-load with 0.5bar intake plenum pressure. One of the PIV planes was vertical, cutting through the centrally located spark plug (tumble plane). The other plane was horizontal 1mm below the spark plug ground electrode (swirl plane). The effect of engine head temperature was also examined by using engine-head coolant temperatures of 20°C and 80°C. The flow field was examined late in the compression stroke at typical ignition timing. The study was conducted under air-only motoring engine conditions but also under fuelled conditions in the early intake stroke using direct injection of gasoline, iso-octane, ethanol and butanol fuels. The flow field under air-only motored conditions showed velocities between 3 and 5m/s predominantly from intake to exhaust. Little differences were observed between hot and cold engine-head temperature; typically ∼10% larger mean velocity and turbulent kinetic energy was seen on the intake side. Integral length scales were on the tumble plane between 2 and 4.5mm in the vertical and 4–7mm in the horizontal direction. The swirl view showed scales between 4 and 10mm, larger at cold than at hot engine-head conditions. The vertical length scales appeared to be limited by the clearance height, scaling typically by about 10–15%. The horizontal components scaled to the cylinder bore diameter by about 5–12%. The fuel injection process in the early intake stroke led to little differences in the general mean flow structure at ignition timing, except for a small increase in the maximum velocities, ∼10%. The turbulent kinetic on the tumble plane was highest towards the exhaust side of the engine under non-fuelled engine conditions but fuel injection resulted in highest values on the intake side. The integral length scales with fuel injection were of the same order of magnitude to those of air only measurements on the tumble plane, but showed distinctly larger areas with length scales up to 9mm on the swirl plane. Differences between fuels for their fuel specific injection duration were small, with average length scales between 4 and 6mm. Ethanol exhibited typically largest scales and butanol smallest.

Butanol Production by Fermentation of Fruit Residues

The feedstock of the Acetone-Butanol-Ethanol (ABE) fermentation is a key issue for the economic success of the biotechnological route to produce biobutanol. Residues from agro-alimentary industries are particularly interesting as renewable substrates for the ABE fermentation because they are abundant and un-competitive with food sources. The residues are also a pressing issue for industries because more than 50% of the processed feedstocks are discharged and their disposal is particularly expensive. However, the high fraction of sugars of the residues makes them a promising interesting feedstock for the production of butanol.This contribution is about the characterization of the ABE fermentation by Clostridium acetobutylicum DSM 792 using sugars from fruit peels. Apple and pear peel extracts were tested as substrate for the fermentation. Batch tests were carried out under a wide interval of peels to water mass ratio. The conversion process was characterized in terms of metabolites and cell production, sugars conversion, specific rate of butanol production and of sugar consumption, butanol and cell yields.The fermentation tests with feedstock peels to water mass ratios lower than 1/6 were characterized by total sugar conversion and low butanol concentration (

Effect of Nutrient Supplementation on Biobutanol Production from Cheese Whey by Abe (acetone–butanol–ethanol) Fermentation

Cheese whey is a liquid effluent obtained from the cheese manufacturing process, presenting a high volumetric production and high organic loads related to its lactose content. The aim of this research was to increase the productivity of ABE fermentation with the bacterial strain Clostridium beijerinckii CECT 508, when using nanofiltered sheep cheese whey as a substrate. Thermal sterilization of the whey was essential to avoid the proliferation of lactic acid bacteria. An experimental design including Plackett-Burman and Response Surface Methodology (RSM) was applied to figure out which additional nutrients were necessary for the fermentation process and their optimum concentrations. For this specific whey, it was established that 1 g/L yeast extract, 5 g/L CaCO3, 0.019 g/L FeSO4·7H2O, 0.2 g/L MgSO4·7H2O and 2.1 g/L NH4Cl needed to be added. Under optimal nutrient conditions, the highest butanol production (9.11 g/L) was obtained with an initial lactose concentration of 57 g/L; achieving 49% lactose consumption and 0.311 g/g YB/L yield. However, the best lactose consumption rate (87%) was recorded for lactose initial concentrations of 30 g/L, which also allowed satisfactory fermentation values (8.51 g/L butanol and 0.328 g/g YB/L yield). On the other hand, the best YB/L yields (0.428 g/g; which is close to the theoretical value) were obtained for initial lactose concentrations of 40 g/L, attaining a value of 52% lactose consumption and 8.91 g/L butanol. Therefore, the ABE fermentation could be a feasible solution to treat cheese whey and remove lactose, obtaining acceptable amounts of butanol.

Sintezna biologija za proizvodnjo biobutanola

In 2015, the first-ever Slovenian high school team competed at the iGEM (international Genetically Engineered Machine) competition in synthetic biology. The team was carefully selected from a list of candidates proposed by their high school teachers of chemistry and biology. Composed of eight students from 7 high schools from across the country, the team split into two groups, working in two institutions but with regular common meetings. The group of four students who worked at the National Institute of Chemistry focused on biotechnological production and the second group was preparing genetic constructs at the University of Ljubljana Faculty of Chemistry and Chemical Technology. The central problem that students tangled was the conversion of C-4 acids that are side-products of anaerobic waste degradation, into the corresponding alcohol. In the biotechnological part of the project students tested butanoic acid production in an anaerobic fermentation broth using a 15-channel computer-controlled bioreactor system, configured to allow online analysis of gaseous products (by GC) and frequent analysis of dissolved compounds (by HPLC). Next, at optimal butanoic acid production conditions (c = 1 g/L butanoic acid) growth of E. coli was examined in terms of medium composition, temperature and pH in order to obtain optimal operational parameters for biotechnological transformation of butanoic acid to butanol. Overall, E. coli growth was analysed in 72 different growth media in microtiter plates. Students followed inhibition of E. coli growth by butanol, acetone and isobutanol in the presence of butanoic acid and glycerol. The synthetic biology group started with PCR amplification of three genes ( ctf A and ctf B encoding two polypeptide chains of Co-A transferase, and bdh B encoding butyraldehide dehydrogenase for a two.stage conversion of butyril CoA to butanol) from anaerobic microbial community. Amplification failed, probably due to contaminants in the broth and a low number of bacteria harbouring these genes. Consequently, synthetic genes were designed with appended sequences for easier cloning, for a hexahistidine tag for detection of recombinant proteins using specific antibodies. Synthetic genes were inserted into pSB1C3 vectors and for each of them a strong promoter- ribosome binding site region was inserted in front of the enzyme coding region. Such combined constructs were further transferred into vectors with double terminators of transcription. In total, 9 different DNA constructs were prepared and deposited in the Registry of biological parts. All final expression constructs efficiently directed production of recombinant enzymes in E. coli DH5α under aerobic conditions. The giant jamboree of competing teams took place in Boston, USA, from September 24 to 28 with more than 260 teams from around the globe. In the high school track the Slovenian team presented the project entitled “From waste to fuel: Reprogrammed E. coli for sustainable production of biobutanol from butanoic acid”. The project received high recognition, as it was awarded a gold medal for completed tasks and was nominated among five best teams in categories Best Integrated Human Practices, Best Wiki, Best Presentation and Best High School Project.

A Review on Butanol and Ethanol Fuels in Internal Combustion Engines

A controversial argument about alternative fuels is taking lots of researchers and scientists attention and so far ethanol and butanol, regardless their blending percentage, are the most promising alcohols due to their potential properties and low production cost. Many studies have been conducted to justify the optimum fuel to be implemented. In this work, a review will be conducted on both butanol and ethanol in internal combustion engine as well as their contribution in combustion engine regarding combustion performance, pollutant emission, ignition timing and knocking. According to the previous literature, an attractive advantage for alcohol-gasoline blends is that they don’t require engine modification design and still reduce the pollutant emission effectively. The properties of these fuels seem to prove not only that we can run our engines with a reduction of pollutant gases but with the emission of greenhouse gasses. This work will provide a review on ethanol and butanol as an alternative fuels and their properties and behaviour in the engine will be described individually.

A comparison of butanol and ethanol flame development in an optical spark ignition engine

The work was concerned with experimental study of the turbulent flame development process of ethanol and butanol fuels in an optically accessed spark ignition research engine. The fuels were evaluated in a single cylinder engine equipped with full-bore overhead optical access and operated at typical stoichiometric part-load conditions. High-speed natural light (or chemiluminescence) imaging and simultaneous in-cylinder pressure data measurement and analysis were used to understand the fundamental influence of both low and high carbon content in alcohol fuels on turbulent flame propagation and subsequent mass burning with the potential to solidify butanol’s reputation as a possible mainstream fuel additive. Overall, it was concluded that the butanol blend tested was similar to the ethanol blend tested in terms of combustion duration, pressure development and flame radius development. This was to be expected with equal oxygen weighting but further highlights butanol’s ability to surpass ethanol as one of the gasoline industry’s fuel additive of choice.