Energy Consumption of Corn Stover Size Reduction

Corn-based ethanol, the most common first generation biofuel in the US, plays an important role as a fossil fuels alternative. Second generation biofuels, which are mostly based on lignocellulosic biomass, have gained great attention in recent years. Size reduction of the lignocellulosic biomass is a key step to the efficiency of downstream processes (i.e., pretreatment, enzymatic hydrolysis, and fermentation), which will affect the yield of ethanol significantly. However, size reduction consumes considerable energy itself, it is an expensive process and needs to be optimized. Some studies have been done on corn stover size reduction, but none of them have examined the initial particle size of feedstock as a variable, and they failed to take the biomass harvest and storage conditions and downstream process requirements into consideration when setting the variables. The objective of this research was to study the effect of initial particle size of corn stover, moisture content, and screen size on energy consumption of corn stover size reduction. Consequently, these results should be generally applicable over a range of conditions that are affected by corn stover harvest and storage conditions and downstream processing

A Corn Stover Supply Logistics System

Published in Applied Engineering in Agriculture, Vol. 26(3): 455‐461, 2010. American Society of Agricultural and Biological EngineersCorn stover, Economics, GHG emission, Logistics, Roll press compaction, Tub grinding, Agribusiness, Crop Production/Industries,

The Viability of Harvesting Corn Cobs and Stover for Biofuel Production in North Dakota

This study examines the impact of stochastic harvest field time, corn cob and stover harvest technologies, increases in farm size, and alternative tillage practices on profit maximizing potential of corn cob and stover collection in North Dakota. Using three mathematical programming models, we analyze farmers’ harvest activities under 1) corn grain only harvest option, 2) simultaneous corn grain and cob harvest(one-pass) option 3) separate corn grain and stover harvest (two-pass) option. Under the first corn grain only option, farmers are able to complete harvesting corn grain and achieve maximum net income in a fairly short amount of time with existing combine technology. However, under the simultaneous corn grain and cob one-pass harvest option, our findings indicate that farmers generate lower net income as compared to the net income of corn grain only harvest option. This is due to the slowdown in combine harvest capacity as a consequence of attaching cob harvester to the back of combine. Under the third option of a two-pass harvest system, time allocation is the main challenge and our evidence shows that with limited harvest field time available, farmers find it optimal to allocate most of their time harvesting grain, and then proceed to bale stover if time permits at the end of harvest season. As farm size increases, farmers are especially challenged in finding time to harvest both corn grain and cobs/stover. We show that a small decrease in corn yield due to changes in tillage practice can result in a large decline in the net profit of harvesting corn grain and cobs/stover.Cob, Stover, harvest field time, optimization, farm size, tillage, Crop Production/Industries, Production Economics,

Finding Balance: Agricultural Residues, Ethanol, and the Environment

Outlines the environmental impact of using wheat straw or corn stover for ethanol production. Makes policy recommendations for ensuring the adoption of best management practices such as no-till production, cover crops, and precision fertilizer management

Long-Term and Global Tradeoffs between Bio-Energy, Feed, and Food

Projections of U.S. ethanol production and its impacts on planted acreage, crop prices, livestock production and prices, trade, and retail food costs are presented under the assumption that current tax credits and trade policies are maintained. The projections were made using a multi-product, multi-country deterministic partial equilibrium model. The impacts of higher oil prices, a drought combined with an ethanol mandate, and removal of land from the Conservation Reserve Program (CRP) relative to baseline projections are also presented. The results indicate that expanded U.S. ethanol production will cause long-run crop prices to increase. In response to higher feed costs, livestock farmgate prices will increase enough to cover the feed cost increases. Retail meat, egg, and dairy prices will also increase. If oil prices are permanently $10-per-barrel higher than assumed in the baseline projections, U.S. ethanol will expand significantly. The magnitude of the expansion will depend on the future makeup of the U.S. automobile fleet. If sufficient demand for E-85 from flex-fuel vehicles is available, corn-based ethanol production is projected to increase to over 30 billion gallons per year with the higher oil prices. The direct effect of higher feed costs is that U.S. food prices would increase by a minimum of 1.1% over baseline levels. Results of a model of a 1988-type drought combined with a large mandate for continued ethanol production show sharply higher crop prices, a drop in livestock production, and higher food prices. Corn exports would drop significantly, and feed costs would rise. Wheat feed use would rise sharply. Taking additional land out of the CRP would lower crop prices in the short run. But because long-run corn prices are determined by ethanol prices and not by corn acreage, the long-run impacts on commodity prices and food prices of a smaller CRP are modest. Cellulosic ethanol from switchgrass and biodiesel from soybeans do not become economically viable in the Corn Belt under any of the scenarios. This is so because high energy costs that increase the prices of biodiesel and switchgrass ethanol also increase the price of corn-based ethanol. So long as producers can choose between soybeans for biodiesel, switchgrass for ethanol, and corn for ethanol, they will choose to grow corn. Cellulosic ethanol from corn stover does not enter into any scenario because of the high cost of collecting and transporting corn stover over the large distances required to supply a commercial-sized ethanol facility.biofuels, corn acreage, crop prices, ethanol production, food prices, Resource /Energy Economics and Policy,

The Potential Viability of Biomass Ethanol as a Renewable Fuel

Much attention has been paid to alternative fuel sources of late. Ethanol has been a politically popular alternative fuel additive and has recently been pushed to the forefront as a leading replacement to MTBE as an oxygenate. This paper examines the potential markets for ethanol, including biomass ethanol, and discusses the strengths and weaknesses of different oxygenate products. We find that the market for ethanol is tenuous and dependent on government support at this time. Biomass ethanol is more expensive to produce, but does have the advantage of being able to be produced near petroleum refineries, thus reducing transport costs, compared to other sources of ethanol.biomass, ethanol

THE POTENTIAL VIABILITY OF BIOMASS ETHANOL AS A RENEWABLE FUEL SOURCE: A DISCUSSION

Much attention has been paid to alternative fuel sources of late. Ethanol has been a politically popular alternative fuel additive and has recently been pushed to the forefront as a leading replacement to MTBE as an oxygenate. This paper examines the potential markets for ethanol, including biomass ethanol, and discusses the strengths and weaknesses of different oxygenate products. We find that the market for ethanol is tenuous and dependent on government support at this time. Biomass ethanol is more expensive to produce, but does have the advantage of being able to be produced near petroleum refineries, thus reducing transport costs, compared to other sources of ethanol.Resource /Energy Economics and Policy,

Application of the rollermill and hammermill for biomass fractionation

Much research is being done to establish corn stover. Stover as an economical feedstock for ethanol and other industrial processes has many advantages including low cost, high production, and low competition. However; corn stover has disadvantages due mainly to its low density and heterogeneous make-up. Research was performed to evaluate and compare a hammermill versus a rollermill as two grinding methods to reduce particle size and change chemical distribution. The hammermill generated finer particles of a relatively homogenous nature, while the rollermill generated a broader particle size spread with differences in chemical composition for the different sizes. The rollermill created a 1% shift in lignin content, a 2% shift in ash content, an 8% shift in Hemicellulose content, and a 4% shift in cellulose content compared to the untreated control

A critical review on sustainable biochar system through gasification: energy and environmental applications

This review lays great emphasis on production and characteristics of biochar through gasification. Specifically, the physicochemical properties and yield of biochar through the diverse gasification conditions associated with various types of biomass were extensively evaluated. In addition, potential application scenarios of biochar through gasification were explored and their environmental implications were discussed. To qualitatively evaluate biochar sustainability through the gasification process, all gasification products (i.e., syngas and biochar) were evaluated via life cycle assessment (LCA). A concept of balancing syngas and biochar production for an economically and environmentally feasible gasification system was proposed and relevant challenges and solutions were suggested in this review

LCA and TEA of Corn Stover Size Reduction

Cost and environmental impacts are the two key issues related to the development of biofuels. The size reduction process of feedstock for the production of lignocellulosic ethanol, a second generation biofuel, is energy-intensive and costly. In this study, life cycle analyses and techno-economic analyses were conducted for six different scenarios of corn stover size reduction. Six grinding condition combinations of three different moisture content (5%, 10%, 20%, wet basis) and two different screens (2 mm, 6 mm) of a knife mill were each used for the six scenarios. The cost and environment impact was compared for each scenario on the basis of producing the same amount of fermentable sugars. A comparably cost-efficient and environmentally friendly corn stover size reduction scenario was concluded