Ethanol Manufacturing Research Articles

Isolated Iridium Sites on Potassium‐Doped Carbon‐nitride wrapped Tellurium Nanostructures for Enhanced Glycerol Photooxidation

AbstractMany industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by‐product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium‐doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible‐NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core‐shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X‐ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.

Cassava (Manihot esculenta Crantz)—A potential source of phytochemicals, food, and nutrition—An updated review

AbstractCassava (Manihot esculenta Crantz) is believed to be an important staple food crop providing potential valuable food source as well as variety of phytoconstituents. Its starchy tubers provide a significant source of energy for around 500 million individuals. Among staple crops, it is regarded to be one of the top suppliers of carbohydrates. Its physicochemical qualities, as well as its availability, have made it a captivating food component. Cassava starch is a valuable raw material used to make a variety of both native and modified starch for cooking purposes. They have also been used for a variety of industrial uses. Cassava starch and flour have the potential to be valuable alternatives to rice, maize, and wheat crops. The advantages included being a staple diet for humans, a component of animal feeds, a raw ingredient for food processing, edible coatings, locally produced alcoholic beverages, and ethanol manufacturing. The roots consist of cyanogenic glycosides, which can lead to lethal cyanide poisoning if tubers arse not properly detoxified using different processing methods include washing, fermentation, boiling, peeling and chemical processing to escape toxin content. The current review summarizes cassava's bioactive components which could be a potential source of various pharmaceutical drugs as well as a source of traditional and modern food applications.

Addressing two major limitations in high-solids enzymatic hydrolysis by an ordered polyethylene glycol pre-incubated strategy: Rheological properties and lignin adsorption for enzyme

High-solids enzymatic hydrolysis for biomass has currently received considerable interest. However, the solid effect during the process limits its economic feasibility. This work presented an ordered polyethylene glycol (PEG) pre-incubated strategy for enhancing the auxiliary effect of PEG in a high-solids enzymatic hydrolysis system. The substrate and enzyme were separately pre-incubated with PEG in this strategy. The ordered PEG pre-incubated strategies yielded a maximum glucose concentration of 166.6 g/L from 32 % (w/v) pretreated corncob with an enzymatic yield of 94.1 % by 72 h hydrolysis. Using this method, PEG not only lessened the lignin adsorption to cellulase but also altered particle rheological characteristics in the high-solids enzymatic hydrolysis system as a viscosity modifier. This study offered a new insight into the mechanism behind the PEG synergistic effect and would make it possible to achieve efficient high-solids loading hydrolysis in the commercial manufacture of cellulosic ethanol.

Distillery Effluent Melanoidin Decolorization Induced by a Yeast Strain <i>Candida tropicalis</i> (Y-2)

Molasses is used in the manufacturing of ethanol at sugarcane distilleries, which also produces a significant volume of effluent with melanoidin pigment and high BOD, COD, and pH. Melanoidin is a dark brown pigment that may be treated before disposal since it has a number of harmful consequences. This study’s objective was to identify possible melanoidin pigment-decolorizing yeast from natural resources and optimize it for various physiological, chemical, and dietary factors. From the various samples taken from the neighbouring distillery site, a total of 15 yeasts were isolated. Candida tropicalis (Y-2) was the name of the yeast strain that had the most colour decolorization. Within 32 hours of incubation, this strain of yeast displayed maximal decolorization (83%) at 35°C with 0.5% glucose, 0.5% peptone, 0.05% MgSO4, and 0.01% KH2PO4 pH-5. This yeast displayed maximal decolorization in the shortest amount of time while using the least quantity of carbon and nitrogen sources. This yeast strain may be used on an industrial scale to decolorize melanoidin since it is exceedingly successful. This is the first investigation of this unique strain of yeast that decolorizes spent wash.

Pengaruh Konsentrasi Crude Enzim Bacillus subtilis IFO 13719 terhadap Kadar Gula dan Etanol Fermentasi Kulit Coffea arabica Menggunakan Zymomonas mobilis IFO 13756

Fossil energy is part of the needs of people in any country, including Indonesia. The need for fossil energy is increasing day by day. Therefore, efforts were made to find alternative raw materials from the non-food sector for the manufacture of ethanol. Cellulose material has potential as an alternative raw material for the manufacture of ethanol. One of the wastes that can be used is Arabica coffee skin. This study aims to determine the effect of the concentration of crude cellulase enzyme on sugar and ethanol content of fermented Arabica coffee husk using Zymomonas mobilis and to determine the concentration of crude cellulase enzyme which produces the highest sugar and ethanol content of fermented Arabica coffee husk using Zymomonas mobilis. This research is an experimental study with the independent variables, namely the concentration of crude cellulase enzymes, namely 0%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, and 17.5% (V/V), and the dependent variable is the sugar content of hydrolysis with crude cellulase enzyme and the ethanol content of fermented with Zymomonas mobilis. The results of the experimental research were analyzed using regression test, ANOVA, and Duncan's test. The addition of crude cellulase enzyme Bacillus subtilis influence the increase in sugar and bioethanol content of fermented Arabica coffee husks using Zymomonas mobilis. The highest sugar content in the P6 treatment (concentration of crude cellulase enzyme Bacillus subtilis 15%) was 0.93 g/mL. The highest levels of bioethanol in treatment P4 (crude cellulase enzyme Bacillus subtilis concentration 10%) was 4.46%.

Vinasse for sugarcane crop nutrition: accumulation and efficiency in the use of nutrients

The use of agro-industrial by-products such as biofertilizers hinders polluting discharges and allows savings commercial fertilizers. The application of vinasse (a by-product of ethanol manufacture) in sugarcane (Saccharum officinarum) production was evaluated in two soils of Uruguay (L1 and LB2). In a first ratoon crop, 150 and 300 m3 ha-1 of vinasse were applied (V150 and V300) and compared with the application of fertilizer (F) and a Control (C) with no application. Then, production and the plant’s N, P, K, Ca and Mg contents were determined. Vinasse and fertilizer applications increased sugarcane growth, as compared to C. However, there were no differences between vinasse dosses. The L1 fertilization treatment produced higher stem yield than vinasse application, whereas LB2 caused no differences. The application of vinasse at LB2 and L1 increased K uptake, exceeding the control, by 151 and 133 kg ha-1 of K, respectively, indicating that it could substitute fertilizer, while supplemental nitrogen fertilization would be required for maximum yield. The low use-efficiency of potassium (K) in vinasse treatments suggests that there was excessive consumption. Although vinasse increased soil exchangeable K, its residual effect would be insufficient for the second ratoon harvest, requiring annual applications

Environmental and Health Consequences of Distillery Wastewater and Ways to Tackle: A Review

Liquid sludge, due to its low pH, elevated temp, dark brown hue, high ash content, a high proportion of organic and inorganic dissolved materials, and high biochemical oxygen demand, distillery wastewater is one of the most harmful pollutants that must be disposed off. The brightly colourful quality of the washed wash, which may obscure sunlight and reduce water oxygenation through photosynthesis, is the first way that the washed wash polluted the water bodies. This is harmful to aquatic life. The second problem is that it has a high contamination load that may lead to eutrophication in polluted water sources. Because of the numerous industrial uses of ethanol, including in chemicals, medicines, cosmetics, drinks, food, and perfumes, distilleries are expanding all over the world. The industrial manufacture of ethanol by fermentation results in the release of significant amounts of elevated BOD and COD levels. The food stock and different elements of the ethanol manufacturing process affect its features. To have a better understanding of the phenomena, the function of numerous microorganisms and their enzymes in wastewater treatment has been addressed. Without treatment, distillery wastewater can seriously endanger aquatic life by reducing the amount of dissolved oxygen in the water currents it enters. This paper includes a thorough analysis of current biological treatment methods as well as a list of issues related to distillery wastewater concerns.

Geographical discrimination of ethanol based on stable isotope ratio analysis coupled with statistical methods: The Chinese case study

The demand for the effective traceability of hazardous chemicals is crucial for preventing and controlling chemical spills and other accidents involving hazardous chemicals. The aim of the study was to investigate the correlation between the geographical location of ethanol-producing industrial sites and the carbon, hydrogen, and oxygen stable isotope ratios of the Chinese-manufactured ethanol using statistical classification analysis to enable the traceability of the ethanol. The isotopic data of 54 ethanol samples obtained from 18 different ethanol manufacturing plants in China between 2019 and 2020. The results of the statistical analysis demonstrated that the δ18O values of the ethanol positively correlated with latitudes of the production plants but negatively correlated with the δ13C values of the ethanol. A small number of samples derived from sites that were geographically close to each other could not be visually distinguished by PCA and HCA. However, by applying and comparing the results of classification by LDA, K-NN and Ensemble, an optimal classification model was obtained. Upon application of these models, 96.3% of the ethanol samples were correctly classified based on their geographical origin, indicating that the combination of isotopic ratios and latitude data is practical and effective for measuring the traceability of ethanol.

Biogas production from vinasse derived from ethanol manufacturing using a continuous stirred tank reactor pilot plant

Biogas production from vinasse derived from ethanol manufacturing using a continuous stirred tank reactor pilot plant

Carbon-Efficient Production Scheduling of a Bioethanol Plant Considering Diversified Feedstock Pelletization Density: A Case Study

This paper presents a dual-objective optimization model for production scheduling of bioethanol plant with carbon-efficient strategies. The model is developed throughout the bioethanol production process. Firstly, the production planning and scheduling of the bioethanol plant’s transportation, storage, pretreatment, and ethanol manufacturing are fully considered. Secondly, the carbon emissions in the ethanol manufacturing process are integrated into the model to form a dual-objective optimization model that simultaneously optimizes the production plan and carbon emissions. The effects of different biomass raw materials with optional pelletization density and pretreatment methods on production scheduling are analyzed. The influence of demand and pretreatment cost on selecting a pretreatment method and total profit is considered. A membership weighted method is developed to solve the dual-objective model. The carbon emission model and economic model are integrated into one model for analysis. An example is given to verify the effectiveness of the optimization model. At the end of the paper, the limitation of this study is discussed to provide directions for future research.

Analysis of sorghum content in corn–sorghum flour bioethanol feedstock by near infrared spectroscopy

In the sorghum-growing regions of the United States, some bioethanol plants use mixtures of corn and sorghum grains as feedstocks depending on price and availability. For regulatory purposes and for optimizing the ethanol manufacturing process, knowledge of the grain composition of the milled feedstock is important. Thus, a near infrared spectroscopy method was developed to determine the content of sorghum in corn–sorghum flour mixtures. Commercial corn and sorghum grain samples were obtained from a bioethanol plant over an 18-month period and across two crop seasons. An array of corn–sorghum flour mixtures having 0–100% sorghum was prepared and scanned using a near infrared spectrometer in the 950–1650 nm wavelength range. A partial least squares regression model was developed to estimate sorghum content in flour mixtures. A calibration model with R2 of 0.99 and a root mean square error of cross validation of 3.91% predicted the sorghum content of an independent set of flour mixtures with r2 = 0.97, root mean square error of prediction = 5.25% and bias = −0.49%. Fourier-transform infrared spectroscopy was utilized to examine spectral differences in corn and sorghum flours. Differences in absorptions were observed at 2930, 2860, 1710, 1150, 1078, and 988 cm−1 suggesting that C–H antisymmetric and symmetric, C=O and C–O stretch vibrations of corn and sorghum flours differ. The regression coefficients of the near infrared model had major peaks around overtone and combination bands of C–H stretch and bending vibrations at 1165, 1220, and 1350 nm. Therefore, the above results confirmed that sorghum content in corn sorghum flour mixtures can be determined using near infrared spectroscopy.

A Miracle Metal@Zeolite for Selective Conversion of Syngas to Ethanol

Direct catalytic conversion of syngas provides a desirable route for ethanol manufacture; however, it still suffers from poor ethanol selectivity and insufficient catalyst durability. In this issue of Chem, Wang et al. design a catalyst with a metal@zeolite core-shell structure, enabling remarkably high ethanol production from syngas with long-term stability.

Evaluation of the inter-particle interference of cellulose and lignin in lignocellulosic materials

The inter-particle interference of lignocellulosic materials describes the order of the macromolecules at a larger size scale, which can give information about the pore structure, and interface of cellulose and lignin. The pore structure and interface influence the rate of enzymatic hydrolysis and thermal decomposition in cellulosic ethanol manufacturing. In this study, the inter-particle interference of cellulose and lignin of three major categories of lignocellulosic materials: wood-based (cedar and oak), energy crop (bamboo), and agricultural or forestry waste (palm) were evaluated. Scanning electron microscopy (SEM) reveals morphological irregularities in the case of bamboo and palm, which may form nucleation sites for faster accessibility to enzyme molecules. Small-angle X-ray scattering (SAXS) shows increased power-law exponent for palm, suggesting a less clustered structure, which was consistent with the rough surface morphology as detected by the SEM. Differential Scanning Calorimetry (DSC) showed a higher temperature maximum for cedar and oak, which is indicative of higher intermolecular forces within their organic compounds, and could result in slower disintegration of the macromolecules during biochemical processing. This study will help to estimate the activity of the macromolecules and absorption capacity of lignocellulosic materials during biochemical processing.

Investigation of molecular and supramolecular assemblies of cellulose and lignin of lignocellulosic materials by spectroscopy and thermal analysis

The study of lignocellulosic materials calls for understanding the structure, and function of different cellulosic materials from diverse sources to scale-up cellulosic ethanol production. For the first time, a systematic assessment of the molecular and supramolecular structure highlighting the similarities and dissimilarities of three major categories of lignocellulosic materials: wood-based (cedar and oak), energy crop (bamboo), and agricultural or forestry waste (palm) are reported. The cellulose, hemicellulose, and lignin constituents were compared for their suitability in cellulosic ethanol production. FTIR showed structural variations within the functional groups with notable OH group in the palm and CC group in cedar. From the X-ray scattering, bamboo exhibited the highest crystallinity (49.5%), and palm showed the lowest crystallinity (22.6%) and crystallite size (2.6 nm). TGA revealed high cellulose amount and stable structure for cedar and oak, and the most unstable structure in the palm, which indicates a better cellulose/hemicellulose accessibility and biodegradability for enzymatic or chemical action in the palm. This comparative assessment can greatly facilitate material selection and component mixture, for developing an efficient and cost-effective biochemical process in ethanol manufacturing.

Biofiltration of acetaldehyde resulting from ethanol manufacturing facilities

At ethanol plants, the control of acetaldehyde emissions is accomplished by scrubbers and regenerative thermal oxidizers. However, their operation imposes substantial operating costs. Alternatively, two biotrickling filters were operated in parallel under acetaldehyde loadings ranging from 4 to 136 g m−3 hr−1. One filter was operated at room temperature while the other one was heated to 60 °C, to mimic hot drier emissions. The unheated filter maintained 100% removal efficiency up to 45.28 g m−3 hr−1 loading rate at 30-s empty bed residence time. Highest elimination capacity recorded was 112 g m−3 hr−1 at 83.2% removal efficiency. The heated filter achieved removal efficiency larger than 60% at influent concentrations of 200 ppmv and lower, however, removal was significantly lower at 400 and 600 ppmv influent concentrations. Performance was improved by reseeding with cooking compost resulting in increased thermophilic bacterial population. Main byproduct formed was acetic acid with traces of formic acid. Mathematical modelling was used to successfully describe acetaldehyde concentration profiles.

Treatment of vinasse from sugarcane ethanol industry: H2SO4, NaOH and Ca(OH)2 precipitations, FeCl3 coagulation-flocculation and atmospheric CO2 carbonation

Vinasse is a key by-product of the ethanol manufacturing industry. Several processes have been studied for the first time in order to treat sugarcane vinasse. Removals of the absorbances (220, 254 and 410 nm) and nutrients (Ca, Mg, P, N, K and Na)≤36% were achieved in the H2SO4 precipitation with the production of a low sludge volume (rich in organic matter and magnesium). A nominal chemical oxygen demand (COD) decline = 12% was also noted when using H2SO4 precipitation, owing to the presence of soluble organic acids in vinasse. Operating pH in the Ca(OH)2 precipitation affected the removal of COD, absorbances and nutrients, obtaining high efficiencies (COD = 51%, absorbances = 88–100%, Mg = 91%, N = 74%, K = 37%, P = 95%, Na = 20%) for high precipitation pH (12–12.5). High depletions in the Ca(OH)2 precipitation can be explained by the formation of insoluble species and polymerization and precipitation of fatty acids, producing a sludge rich in Ca, P, K and Mg. Comparable results were attained for the thermocalcic precipitation. NaOH precipitation treatability for the vinasse decontamination was based on the removals of Ca (80%), P (74%), Mg (64%), N (24%), K (19%), generating a sludge rich in organic matter and nutrients (Mg, K, P and Na). The supernatant produced in the Ca(OH)2 precipitation, under optimal conditions, was subjected to: 1) a coagulation-flocculation step with FeCl3 addition (1 g L−1), improving the removals of absorbance at 410 nm, COD, phosphorus and volatile solids (VS); and 2) a novel green technology (natural carbonation) for the atmospheric CO2 mitigation with treatment and neutralization of the effluent.

Comparative analysis of key technologies for cellulosic ethanol production from Brazilian sugarcane bagasse at a commercial scale

AbstractBiorefineries can upgrade waste lignocellulosic biomass (LB) into soluble (C5 and C6) sugars that can be fermented into second‐generation (2G) ethanol‐based biofuels and a range of valuable byproducts derived from lignin. Research advances made in various laboratories worldwide have not been easy to translate into large‐scale operations. Here, we performed a simple economic analysis of cellulosic ethanol production from a stand‐alone 100ton dry sugarcane bagasse per day process, from a Brazilian market perspective, based on current state‐of‐the‐art biorefinery process technologies. Economic analysis reveals that the cost of manufacturing (COM) of 2G ethanol in an annexed Brazilian facility is close to USD 1.33 L−1. Fixed and variable costs contributed 57% and 24% in COM of 2G ethanol with a high payback period of ~31 years and a negative net present value (NPV). Further cost reduction can be realized by continuous R&D efforts aiming for innovation in new processing paradigms for cellulosic biorefineries. The key market players (Poet‐DSM, DuPont, Abengoa, Beta Renewables, Raizen, Granbio, Praj, etc.) and other new emerging players (Global Yeast, Taurus Energy, Leaf, Mascoma‐Lallemand) working on ethanologen development, and cellulase producers (Novozyme, Metgen), should also develop partnerships / joint ventures to establish a sustainable business model to develop cost‐competitive 2G ethanol production from bagasse in Brazil. This paper presents additional commentary and analysis with pertinent information about the commercialization of integrated 2G ethanol biorefineries processing sugarcane bagasse, from a Brazilian perspective. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd

Performance optimisation for ethanol manufacturing system of distillery plant using particle swarm optimisation algorithm

The paper deals with performance optimisation for ethanol manufacturing system of distillery plant using particle swarm optimisation (PSO) algorithm. The performance of the system is first estimated with the help of transition diagram and a mathematical model based on Markov approach in real working environment. The differential equations associated with the transition diagram are developed assuming that the failure and repair rate parameters of each component follow the exponential distribution. The long-run availability expression for the system has been derived with probabilistic approach using normalising condition. The availability of the system is then computed with the help of PSO technique and compared with the genetic algorithm (GA) results to verify the solution. The results show that PSO modifies the solution more precisely and provides the optimum combinations of failure and repair rate parameters for various subsystems which are practically useful in maintenance planning for plant personnel.

Production optimization for concentration and volume-limited fed-batch reactors in biochemical processes.

Since a very slight violation of constraint could cause process safety and product quality problems in biochemical processes, an adaptive approach of fed-batch reactor production optimization that can strictly satisfy constraints over the entire operating time is presented. In this approach, an improved smooth function is proposed such that the inequality constraints can be transformed into smooth constraints. Based on this, only an auxiliary state is needed to monitor violations in the augmented performance index. Combined with control variable parameterization (CVP), the dynamic optimization is executed and constraint violations are examined by calculating the sensitivities of states to ensure that the inequality constraints are satisfied everywhere inside the time interval. Three biochemical production optimization problems, including the manufacturing of ethanol, penicillin and protein, are tested as illustrations. Meanwhile, comparisons with pure penalty CVP method, famous dynamic optimization toolbox DOTcvp and literature results are carried out. Research results show that the proposed method achieves better performances in terms of optimization accuracy and computation cost.

Valorization of Grass Lignins: Swift and Selective Recovery of Pendant Aromatic Groups with Ozone

The lack of a simple process for valorizing the lignin produced during cellulosic ethanol manufacture is a major hurdle preventing such biorefineries from becoming economically sustainable. Here, we demonstrate a facile ozonolysis process in a continuous stirred tank reactor (CSTR) to generate a value-added product stream from lignin dissolved in either acetic acid (as in acetosolv lignin) or formic acid. At ambient pressure, relatively mild temperature (70 °C), and short residence times (few minutes), ozone is bubbled through the solution to selectively cleave the C═C bonds associated with specific pendant groups present in corn stover and wheat straw lignins. The resulting products, mainly vanillin and 4-hydroxybenzaldehyde, constitute approximately 7 wt % of the lignin and command high value with established applications in the flavoring, pharmaceutical, and electronics industries. These products are easily separated from the remaining lignin via membrane nanofiltration of the product mixture. The lign...