Ethanol Production Cost Research Articles

Technology and economics of ethanol production from fodder beets via solid-phase fermentation

Operating conditions for our semi-continuous, solid-phase fermentation system were optimized for conversion of fodder beets to fuel ethanol and distiller's wet feed (DWF). This information was then used to estimate operating parameters achievable in a commercial plant, and likely baseline production costs of such a plant. Initial acidification of pulp to pH 2.9–3.2 was effective in controlling bacterial contamination. The maximum operating capacity of the fermentor was approximately 92%, with 75% used for commercial application. A fermentation time of 24 h was sufficient to completely ferment the beet pulp to 8–9% (v/v) ethanol. Based on these parameters, a fodder beet cost of $19.25/metric ton ($17.50/ton), other operating and capital costs, and a PF credit of $0.14/L ($0.53/gal), ethanol production costs were estimated to be $0.49/L ($1.87/gal).

Processing cereal grains, thin stillage, and cheese whey to fuel ethanol in a farm-scale plant

Hydrous fuel ethanol (95%) and distiller's wet grain (DWG) were produced in a farm-scale plant (< 4 million liters ethanol year −1) from corn, wheat, and grain sorghum particles of various sizes, from corn combined with thin stillage-whey, and from various other cereal grains. These variations were made in a search to find the best set of conditions for maximizing the energy balance (energy output divided by energy input) and minimizing the cost of ethanol production. We found that the optimum hammermill screen size for corn, wheat, and grain sorghum was 1·59–2·38 mm. In tests with thin stillage and whey a higher energy balance (2·91) occurred when one part whey was mixed with three parts stillage, rather than the reverse (2·69). However, the reverse (three parts whey and one part stillage) gave a lower ethanol cost ($0.45 liter −1) than the original ($0.47 liter −1). Tests with various cereal grains (corn, oats, wheat, barley, rye, and grain sorghum) gave identical energy balance values (2·26) when 10% (v/v) ethanol beers were produced. However, rye ($0.50 liter −1), grain sorghum ($0.46 liter −1), and corn ($0.51 liter −1) yielded ethanol at the lowest net cost. Recommendations for farm-scale plants are also provided.

Substitution of petroleum products in Brazil Urgent issues

Brazilian energy policy in recent years has focused on curbing demand for imported petroleum by fostering conservation and substitution with domestic energy resources. These measures have resulted in substantial surpluses of both gasoline and fuel oil, thereby weakening the case for continued subsidization of alternatives to those fuels. The pace of oil substitution must be revised and policies reassessed. The areas deserving the highest priority are the cost and productivity of ethanol (alcohol fuel) production, electricity tariffs, motor fuel policy, and the role of fuel oil in industrial energy demand.

Sulfuric acid-sugar separation by ion exclusion

Abstract Biomass conversion continues to have significant potential in the production of fuel ethanol by fermentation. A major cost in acid hydrolysis of biomass to fermentable sugars is the acid itself. Separation and recyle of the acid could reduce ethanol production costs by $0.10 / gallon or more. In this context, a process that separates sulfuric acid from glucose using ion-exclusion technology is presented. A 61 cm long, fixed-bed of Rohm and Haas Amberlite IR-118, strong cation-exchange resin in the hydrogen form was used. Samples containing 7.7% H2SO4 and 1.0% glucose, at sample volumes of 10% to 50% of the column void volume gave separation of H2SO4 from glucose at column temperatures ranging from 27 to 81°C with water as eluent at a superficial velocity of 0.6 cm/min. Skewing of the H2SO4 peak was observed and traced to a sharp density gradient between the acid and the water eluent while the glucose peak was sufficiently symmetric to be fitted by an axial dispersion model. This work shows that a chromatographic resin having a particle size range of 300 to 1200 micrometers can give complete recovery of sulfuric acid with 94% recovery of glucose. This case study has interesting implications for both the practice of process chromatography, using a resin with large particle size at gross loading conditions, and the prospects of further reducing fermentable sugar costs in biomass conversion.

Der Einfluß der Prozeßparameter auf die Ethanolausbeute in Batchprozessen bei Verwendung von Saccharomyces cerevisiae

AbstractThe production costs of ethanol are dependent on the efficiency of the substrate‐ethanol conversion to a high degree. The more the substrate used during the fermentation is converted into alcohol the better is the economy of the process.Therefore the ethanol yield Y SP is an important object of the process optimization.In batch fermentation processes the most essential influence factors are the initial biomass concentration X0, the initial substrate concentration S0, the temperature T, and the pH‐value.A model reflecting the complex relationships between these influence factors and the ethanol yield could be obtained by regression. It allows an exact valuation of these optimum process parameters which are necessary for realizing high ethanol yields in the batch fermentation.For the strain Saccharomyces cerevisiae Sc 5 used in this research was found an ethanol yield maximum YSP = 0˙5384 at the parameters X0 = 64.61 g/l S0 = 82.91 g/l T = 36.45°C pH = 6.54.

The potential for synfuels production from cellulosic papermaking wastes

Papermaking wastes, available in large quantities, have the potential for providing the raw materials for production of commodity chemicals, many of which are suitable for fuels use. A number of techniques are being developed for the recovery of these chemicals. All methods involve three stages: pretreatment, hydrolysis, then fermentation. The hydrolysis techniques include using conventional and non-conventional pulping, acid hydrolysis, high temperature and pressure, microbial digestion (fermentation), or combinations of these. Several recent advances show potential for being cost effective. Estimated production costs for ethanol so produced range as low as 22.5¢/L (85 ¢/gallon U.S.).

The feasibility of national fuel-alcohol programs in Southeast Asia

The feasibility of producing fuel alcohol from crops containing sugars or starch in Southeast Asian countries has been investigated from various points of view. A review of energy balance analysis showed that in fuel-ethanol production from crops the ratio of energy output to energy input is close to or less than unity unless bagasse is used as a heat source. The cost of ethanol production depends mainly on the price of raw material (crops), which may be supported by low labor cost in farming. The total ethanol energy planned to be supplied in the Philippines and Thailand is only 2–4% of the current fossil energy consumption in those countries. Fuel-ethanol production from crops will thus make little contribution to the improvement of trade balance. On the other hand, the exportation of excess crops by the non-oil producing countries is the main source of revenue to be used in the importation of crude oil, petroleum products, machines and so on. Increased land use to cultivate crops for ethanol production would cause large scale destruction of the ecosystem of tropical regions.

Process design and economic studies of alternative fermentation methods for the production of ethanol

AbstractCell recycle and vacuum fermentation processes are described for the continuous production of ethanol. Preliminary process design studies are employed to make an economic comparison of these alternative fermentation schemes with continuous and batch fermentation technologies. Designs are based on a production capacity of 78,000 gal 95% ethanol (EtOH)/day employing molasses as the fermentation substrate. The studies indicate that a 57% reduction in fixed capital investment is realized by continuous rather than batch operation. Further decreases in required capital investment of 68 and 71% over batch fermentation were obtained for cell recycle and vacuum operation, respectively. However, ethanol production costs were dominated by the cost of molasses, representing over 75% of the total manufacturing cost. But, when a reasonable yeast by‐product credit was assumed, the net production cost for 95% ethanol was estimated at 82.3 and 80.6 cent/gal, for the cell recycle and vacuum processes, respectively.

Key drivers influencing the commercialization of ethanol-based biorefineries

The imposition of ethanol derived from biomass for blending in gasoline would make countries less dependent on current petroleum sources, which would save foreign exchange reserves, improve rural economies and provide job opportunities in a clean and safe environment. The key drivers for successful commercial ethanol production are cheap raw materials, economic pretreatment technologies, in-house cellulase production with high and efficient titers, high ethanol fermentation rates, downstream recovery of ethanol and maximum by-products utilization. Furthermore, recent developments in engineering of biomass for increased biomass, down-regulation of lignin synthesis, improved cellulase titers and re-engineering of cellulases, and process integration of the steps involved have increased the possibility of cheap bioethanol production that competes with the price of petroleum. Recently, many companies have come forward globally for bioethanol production on a large scale. It is very clear now that bioethanol will be available at the price of fossil fuels by 2010. This article intends to provide insight and perspectives on the important recent developments in bioethanol research, the commercialization status of bioethanol production, the step-wise cost incurred in the process involved, and the possible innovations that can be utilized to reduce the cost of ethanol production.