Fuel from Farms
A guide to Small-Scale Ethanol Production
Selections

Solar Energy Research Institute
United States Department of Energy
1980

The United States has the potential for growing grains and other crops well in excess of the requirements for domestic and export markets. Economic factors have consequently played a major role in the institution of "set-aside land" and "land diversion" programs by the U.S. Department of Agriculture (USDA). However, growing grain or other crops on this land for fuel production would not detract from the production of food. Rather, if properly utilized, it would constitute a resource that would otherwise have been left idle. Furthermore, the crops grown on this land can still be held in reserve for emergency food, should that become necessary. In 1978, for example, the USDA has certified that the amount of cropland left fallow was 13.4 million acres under the set-aside program and an additional 5.3 million acres under the diversion program. If this acreage had been cultivated with corn for ethanol production, nearly 3.03 billion gallons of ethanol and 10 million tons of distillers' dried grains (DDG) could have been produced. (This assumes a modest average yield of 65 bushels of corn per acre per year with an average production of 2.5 gallons of 200-proof ethanol and 17 pounds of DDG per bushel of corn.) This is only ethanol produced from land left idle through two specific farm programs. The production of fermentation ethanol is not limited by the extent of this land, and additional unused land as well as some land currently under cultivation can be used for crops for production of fermentation ethanol. All this makes the production of ethanol even more promising, and a conservative estimate for the potential displacement of petroleum is at least several billion gallons per year in the near term.

Belt tightening alone will not help the United States solve the present economic difficulties. Farmers, like everyone else, do not like austerity programs and would rather increase our national wealth. This can be achieved by increasing productivity-the production of more goods tand services from every barrel of oil we use and development of new sources of energy.

Clearly, the agricultural sector has a role whose full potential is just beginning to be realized. A farm-based fermentation ethanol industry can provide a dccentralized system of fuel production and a measure of energy self-sufficiency for the farm community. This can be accomplished as an integral part of normal farming operations following sound agricultural practices.

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Benefit

There are three areas in which there are benefits to the farm economy from small-scale, on-farm, ethanol production. These are direct sales, on-farm uses, and indirect farm benefits,

Farm-produced ethanol sold for profit provides an alternative market for farm commodities. It can provide a "shock absorber" for excess production and a "fall back position" if unforeseen events adversely affect crop or yields.

Farming, perhaps more than any other single occupation, offers the opportunity for self-reliance. The on-farm production of ethanol expands this opportunity. Ethanol can be used in farm equipment as a blend with gasoline in spark ignition engines, as anhydrous or hydrated ethanol fuels in modified spark ignition engines, as a blend with diesel fuel in diesel engines, and as a dual-carbureted mixture with water in diesel turbochargers to enhance efficiency. Protein co-products, such as stillage, can be fed to farm animals as a replacement for other protein sources. Cellulosic coproducts, if sufficiently dry, can be burned as fuel.

Farm overproduction is generally planned to meet anticipated demand in the event of possible reductions in crop yield. However, the cumulative result of consistent overproduction in the absence of alternative markets is depressed commodity prices. Consequently, the financial health of many farms depends on the opening of new markets. Fermentation ethanol production provides several alternative markets for a broad variety of farm commodities.
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Fermentation ethanol has replaced a significant portion of petroleum-derived ethanol in India and Brazil [5, 6]. In fact, ethylene is produced from fermentation ethanol in these countries. Similar programs are being developed in the Philippines, South Africa, Australia, and other countries, and it is reasonable to assume that such a development could also occur in the United States.

Other Uses. Other possible uses of ethanol are as fuel for

• crop drying,
• general heating, and
• electricity generation with small generators.

Coproducts

Stillage can be fed to farm animals as a protein supplement either whole (as produced), wet, solid (screened), or dry. The stillage from cereal grains ranges from 26% to 32% protein on a dry basis. The basic limitation on the amount that can be fed at any one time to an animal is palatability (acid concentration caused by drying makes the taste very acrid). Mature cattle can consume about 7 pounds of dry stillage per day or, roughly, the stillage resulting from the production of 1 gallon of ethanol. The feeding of whole stillage is limited by the normal daily water intake of the animal and the re- quirements for metabolizable energy and forage fiber. The feeding value to swine and poultry is somewhat limited. Wet stillage cannot be stored for long periods of time, and the lack of locally available herds of animals to consume it may lower its value. Stillage from grains contaminated with aflatoxins cannot be used as animal feed.

The cellulosic coproducts may be directly fermented to produce methane gas or dried for use as boiler fuel.

Carbon dioxide (CO2) produced by fermentation can be compressed and sold to users of refrigerants, soft drink bottlers, and others. It also has many agricultural applications which are beyond the scope of this handbook.

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Market Assessment

Before a decision to produce can be made, it is necessary to accurately determine if markets for the ethanol and coproducts exist close enough to allow for economical distribution. The size of the market is defined by the quantities of ethanol and coproducts that can be used directly on the farm and/or sold. The ethanol on-farm use potential can be determined from the consumption of gasoline and diesel fuel in current farming operations. Then, a decision must be made on the degree of modification that is acceptable for farm equipment. If none is acceptable, the on-farm use will range from 10% to 2040 of the total gasoline consumption. If direct modification to spark ignition equipment is acceptable, the on-farm potential use can be 110% to 120% of cur- rent gasoline consumption. If the risks associated with attempting undemonstrated technology are considered acceptable, the ethanol replacement of diesel fuel will be roughly 50% of current diesel fuel consumption [3].

The sale of ethanol off the farm will be dependent upon local conditions and upon the type of Bureau of Alcohol, Tobacco, and Firearms (BATF) license obtained. (Currently, a commercial license from BATF is required for off-farm sale of ethanol.) Market estimates should be based on actual letters of intent to purchase, not an intuitive guess of local consumption. The on-farm use of stillage must be calculated on the basis of the number of animals that are normally kept and the quantity of stillage they can consume. The potential for sale of stillage must be computed on the basis of letters of intent to purchase, not just on the existence of a local feedlot. The value of stillage wit1 never exceed the directly corresponding cost of protein from other sources. Direct on-farm use of carbon dioxide is limited; its principal value may come from sales. If Jerusalem artichokes, sorghum, or sugarcane are used, the bagasse and fiber that remain after the sugar is removed may be sufficient to supply the entire energy requirements of the ethanol plant. This value should be calculated in terms of the next less expensive source of fuel.

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Production Potential

Feedstocks

The mix of feedstocks determine in part the actual pro- duction potential. Chapter IV discusses the use and production of the various feedstocks individually and in combination. The guidance offered in that chapter will help define the sizing of the plant from the viewpoint of output, once the potential of the available feedstocks is determined. Additional feedstocks may also be pur- chased and combined with products available on-site.

Water

Significant amounts of water are used in the ethanol production process (about 16 gallons of water per gallon of ethancl produced). This demand includes require- ments for generating steam, cooling, and preparing mashes. Also, it may be desirable to grow a crop not normally produced in the area. If additional irrigation water is necessary for this crop, the increment must be included, but it is likely that stillage liquids can be directly applied to fulfill this need.

Heat Sources

Heat is required in the conversion of feedstocks to ethanol, primarily in cooking, distillation, and stillage drying. An accurate assessment must be made to deter- mine the type and quantity of available heat sources. Waste materials can contribute as energy sources and, from a national energy perspective, the use of petroleum fuels is not desirable. In some cases, other renewable sources of energy such as methane, solar, wind, and geothermal may be used as supplements.

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Financial Requirements

Considerations to Proceed

Once the considerations for equipment selection are completed, the capital and operating costs may be roughly computed.

The capital cost considerations are:

equipment,
real estate and buildings,
permits and licenses, and
availability of financing.

The operating costs are: .
labor,
cost of money.
insurance,
chemicals, enzymes, additives,
fuel,
feedstocks,
costs of delivery, and
bonds.

These considerations are then compared to the specific financial situtation of the individual. If the results of this comparison are not acceptable, then other options in equipment specifications and plant size must be con- sidered. If all possibilities result in an unfavorable posi- tion, the decision to produce is no. If a favorable set of conditions and specifications can be devised, detailed design considerations should be examined (see Chapter V, Plant Design) and an appropriate organization and financial plan developed (see Chapter VI, Business Plan).
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Decision & Planning Worksheets

[See separate document on this web site]

Pp. 14 - 30
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The production of ethanol is an established process. It involves some of the knowledge and skill used in normal farm operations, especially the cultivation of plants. It is also a mix of technologies which includes microbiology, chemistry, and engineering. Basically, fermentation is a process in which microorganisms such as yeasts convert simple sugars to ethanol and carbon dioxide. Some plants directly yield simple sugars; others produce starch or cellulose that must be converted to sugar. The sugar obtained must be fermented and the beer prod:uced must then be distilled to obtain fuel- grade ethanol.

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Production of fuel-grade ethanol is a practical operation to include in farm activities. Texts in microbiology and organic chemistry portray it as a complex pro- cedure, but this is not necessarily true. Fermentation is affected by a variety of conditions. The more care used in producing optimum conditions, the greater the ethanol yield. Distillation can range from the simple to the complex. Fortunately, the middle line works quite satisfactorily for on-farm ethanol production.

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Grain processing as practiced in large plants is not feasible for small plants. However, a simple form of processing to produce human food may be feasible. Wheat can be simply processed to separate the starch from the combined germ, gluten, and fiber. They form a cohesive, doughy mass which has long been used as a base for meat-analogs. This material can also be incorporated into bread dough to enhance its nutritional value by increasing the protein, fiber, and vitamin (germ) content.

Work at the University of Wisconsin has resulted in the development of a simple, practical processing machine that extracts about 60% of the protein from forage crops in the form of a leaf juice [6]. The protein in the juice can be separated in a dry form to be used as a very high quality human food. The fibrous residue is then in good condition to be hydrolyzed to fermentable sugars. Most of the plant sugars are in the leaf juice and, after separation of the protein, are ready for fermentation. Forage crops have the potential for producing large amounts of ethanol per acre together with large amounts of human-food-grade protein. The protein production potential is conservatively 1,000 pounds per acre, equivalent to 140 bushels per acre of 12%-protein wheat [7].

6. Besken, K. E.; et al. "Reducing the Energy Require- ments of Plant Juice Protein Production."Paper presented at the 1975 Annual Meeting of the American Society of Agricultural Engineers; paper no. 75-1056, 1975.
7. Mann, H. 0.; et al. "Yield and Quality-Sudan, Sorghum-Sudan, and Pearl Millet Hybrids." Prog- ress Report, Colorado State University, Fort Collins, co; 1975.

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Agronomic Considerations

A simple comparison of potential ethanol yield per acre of various crops will not rank the crops in terms of economic value for production of ethanol. The crops vary considerably in their demands on the soil, demands for water, need for fertilization, susceptibility to disease or insect damage, etc. These factors critically influence the economics of producing a crop. Fortunately, forage crops which have the potential for producing large amounts of ethanol per acre have specific agronomic advantages relative to some of the principal grain crops (e.g., corn).

The nonfruiting crops, including forage crops, some varieties of high-sugar sorghum, and Jerusalem artichokes, are less susceptible to catastrophic loss (e.g., due to hail, frost, insects, disease, etc.), and, in fact, are less likely to suffer significant loss of production due to adverse circumstances of any sort than are fruiting crops such as grains. Furthermore, forage crops and Jerusalem artichokes are less demanding in their culture than almost any grain. Their cost of culture is usually lower than for grains on the same farm, and they have great potential for planting on marginal land.

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Plant Design

[See separate document on this web site]

Pp. 48-61
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Flexibility in Operation and Feedstocks

Plant profitability should not hinge on the basis of theoretical maximum capacity. Over a period of time, any of a myriad of unforeseen possibilities can interrupt operations and depress yields. Market (or redundant commodity) variables or farm operation considerations may indicate a need to switch feedstocks. Therefore, the equipment for preparation and conversion should be capable of handling cereal grain and at least one of the following:
ensiled forage material;
starchy roots and tubers; or
sugar beets, or other storable, high-sugar-content plant parts.

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TABLE V-3. EQUIPMENT FOR REPRESENTATIVE PLANT
[See separate document on this web site]

Pp. 63-64
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http://eric.ed.gov/?id=ED195447 

Do It Yourself! Build a Small-Scale Ethanol Fuel Plant

Find out what it takes to build an ethanol fuel plant, including sourcing feedstock.

By Richard Freudenberger
May 9, 2013

From Mother Earth News

Alcohol Fuel: A Guide to Making and Using Ethanol as a Renewable Fuel by Richard Freudenberger is a practical, grassroots guide that gives readers all the information they need for making and using ethanol for fuel.

The search for alternative fuel sources has led to the development of ethanol, a gasoline substitute, but large-scale production of corn-based ethanol is controversial and it threatens the world's food supply. In Alcohol Fuel: A Guide to Small-Scale Ethanol (New Society Publishing, 2009), Richard Freudenberger gives readers all the information they need create a small-scale ethanol plant. In this excerpt from Chapter 4, he covers all the production aspects a would-be alcohol producer needs to consider.

Ideally, your ethanol plant would be part of a farm or market-growing venture, for two reasons. First, as a grower you'd already have a familiarity with the day-to-day practices that agriculture entails. This includes working within a routine, searching for markets, dealing with equipment in both fair and inclement weather, and quite importantly, improvising when necessary to keep things running smoothly. As anyone who has worked the land can tell you, the most successful farmers are well-rounded Renaissance people who can roll with the punches and take things in stride.

Second, a working farm provides a ready-made outlet for the manufactured fuel and its by-products. Most any internal-combustion engine or heating appliances can be adapted to run on alcohol — this inventory includes tractors, trucks, pumps, generators, burners and furnaces — and the residual material from mash production contains enough nutrient to supplement normal livestock feed.

If agriculture is not in your background, it's still possible to manufacture alcohol, even economically, provided you have a reliable source of raw material, or feedstock. There are many viable candidates for ethanol production, including both sugar and starch crops. Residues from canning and juicing operations, even far from the farm, are also distinct possibilities. Realistically, it would be difficult to carry on much more than an experimental venture in a confined space such a suburban backyard, but it's still possible. Ideally, a rural setting or a location where there's room to expand and function without interference would be the better choice.

Sourcing Raw Materials

Finding a reliable and consistent source for feedstock material can be a real challenge. Chapter 5 will address the distinction between sugar crops such as cane, sugar beets and fruit juices and starch-based crops such as corn, sorghum, grains and potatoes. (Visit our online store to buy the entire book.) For now, it's enough to say that certain plants produce more starch or sugar per ton or per acre than others, and given the right cost, crops with more concentrated nutrients are the best choice.

To complicate matters, though, is the fact that the equipment needed to process the raw material varies by crop. Grain-grinding machinery is quite a bit different from the extractive equipment used to process sugar beets. Unless you can cultivate a reliable source of feedstock, it would be unwise to invest in any specific equipment. Consider, instead, renting (or leasing) that equipment if possible, or look into using the services of a local co-op.

If you live in a rural community where processing and packing houses exist, you may find that reclaiming surplus and spoilage from these operations makes the best economic sense. Approached properly, most cooperatives and private processing facilities should be willing to negotiate an attractive arrangement — a deal, if you will — that would allow you to test the value of their spoilage as a feedstock, subject to performance results over a specific period of time.

Too, you can always try making arrangements with individual farmers, perhaps in exchange for culling waste from fields and orchards, which will provide you with the needed feedstock material, at least on a temporary basis while you establish its feasibility.

Storage can be an issue with certain crops. Some products should be processed within a few months of harvest, and if they are not, they need to be dried sufficiently to store. Drying and storage come at additional cost, and are best both avoided. You will, of course, have to make some provision for containing your feedstock on a day-to-day basis to keep the operation running smoothly, especially if you plan to operate the still in batches rather than on a continuous basis.

Buy It or Build It?

For the small-scale fuel producer, many still designs are so basic that it's much simpler and far less expensive to build the equipment rather than to buy it. This is especially true of small-capacity operations. Costly stainless steel components aren't needed at this scale — ordinary mild steel pipe will do for the columns and water lines, and in some applications plastic piping can be used. Likewise, tanks and vats need not be anything special, but for those elements, it's often cheaper to just buy used equipment at a farm auction (stainless steel dairy storage and processor tanks are common auction items).

If you have welding skills and a place to work, you're way ahead of the game. For the kind of components involved, there's no real reason to use new materials. Any salvage or metal scrap yard is likely to produce the sort of parts you'll need. If you're not fussy, an old oil tank can make a decent boiler vat, and similar liquid storage containers can be adapted to serve as agitated mash cookers. Many components are make-do items from other applications, so you'll have to use a creative eye when shopping for good candidates. Unfortunately, many manufactured steel items — particularly stainless steel — have increased in value in the pre-owned marketplace because there is an increased foreign market for quality steel salvage in general and for well-made American products in particular, especially among developing nations. The plumbing parts are for the most part standard off-the-shelf items.

Paying for the services of a professional welder will increase the cost of the equipment considerably and perhaps even double it. You can trim expenses by locating all the materials yourself and preparing the parts to be fit and welded prior to delivering the job. The less the welder has to do in shaping, fitting and grinding, the less time he or she will spend on the project, reducing the hourly charge. This prep work is not a particularly high-skilled endeavor, and the investment in tools is very reasonable at this stage, so you might consider taking this approach and saving a few dollars in the bargain.

The Value of Your Time

Unfortunately for some of us, we are blessed with a desire to learn and accomplish rather than driven to make a profit. Such is the case for those working at the preliminary stages of setting up a home-scale distillery. Still, putting a lot of sweat equity into your ethanol project is a sound decision, especially for those who aren't fully committed to the idea of making large volumes of fuel alcohol. It reduces the amount of monetary investment involved (and thus the risk) and also provides you an intimate familiarity with the equipment that you'd never experience simply by purchasing it.

Once you're at the point of producing ethanol, you should place some value on your time, even if it is minimal. Assigning a cost per hour to your labor in collecting and processing feedstock, maintaining the distillery's operation, and handling the ethanol product and its record keeping will allow you to honestly and accurately calculate what it costs to be independent of the normal petroleum fuel network.

Calculating Cost Per Gallon

It is not that difficult to figure out what it will cost you to make a gallon of ethanol fuel, given some degree of stability in the cost of your cooking/heating fuel and feedstock sources. In a traditional farming operation, the costs of production are well established and independent of yield per acre and market value of the crop, until it comes time to calculate the actual level of profit. (View the third image on the first page of this article for sample yields of 190 proof alcohol from different types of crops.)

The situation is similar with ethanol fuel, though many producers, particularly those working with spoilage and processing surplus, will not be concerned with crop yields other than their value in starch or sugars.
In order to keep your computation consistent, it is prudent to convert your alcohol yield to a standard proof measure, especially if you're drawing varying proof percentages of ethanol from your still. I established in Chapter 3 how the revenue authorities calculate ethanol measure for the purposes of taxation; you should use a similar method to determine the value of your fuel. (Visit our online store to purchase the entire book.)

For example, if you've made 100 gallons of 185-proof ethanol in one run and 50 gallons of 190-proof ethanol in another, you can conclude that your yield is 140 gallons of 100 percent ethanol. The actual product, of course, is not that pure, but you're simply establishing a standard common denominator you can work with for the purposes of calculation.

Once that's established, you can determine the cost of your raw material feedstock, calculate the cost of transporting it to your work site, and subtract the value of any by-product yield, whether it's sold as distiller's grain or used for yourself at fair market value. This would include carbon dioxide for bottling, and any cellulosic co-products, which can be fermented to produce methane gas or dried for boiler fuel.

At this point you have a net feedstock value, for which you must now factor the cost of conversion to ethanol. The operating expenditures involved in this process include the cost of supplies such as enzymes and yeast, the cost of fuel to cook the mash and heat the distillation boiler, and the cost of insurance, licensing and any financing. These are added to the net feedstock figure to give you the cost of ethanol prior to adjustments for depreciation and other miscellaneous costs such as electricity for pumping, maintenance and repairs. Depreciation may be the cost of any leased equipment or machinery purchased, which can be extended or amortized over a given period, generally five years. Labor costs can also be considered here, though they may change with increased or decreased production.

The total fuel cost is then established by adding the adjusted costs above to the pre-adjusted cost of your ethanol to get a net cost. Dividing this figure by the number of pure ethanol gallons (not actual gallons) will give you the cost per gallon of your hard-earned product.

Beginning in 2005, an enhanced Small Producer Tax Credit became available with passage of the Energy Policy Act of 2005. Section 40 of the US Internal Revenue Code now allows an eligible small ethanol producer, defined as one manufacturing less than 60 million gallons per year, a federal income tax credit equal to $ .10 per gallon for the first 15 million gallons produced. Individual states may have other such incentives for small producers as well.

This excerpt has been reprinted with permission from Alcohol Fuel: A Guide to Small-Scale Ethanol, published by New Society Publishing, 2009. Buy this book from our store: Alcohol Fuel: A Guide to Small-Scale Ethanol.

Source: http://motherearthnews.com/renewable-energy/diy-ethanol-fuel-plant-zebz1305znsp.aspx#axzz2UpQo7hSk

Farming for Energy

Anil K. Rajvanshi
Director
Nimbkar Agricultural Research Institute (NARI)

A farmer is a multi-purpose entrepreneur. His farm (factory) produces multiple crops (products) which he sells in the market. Yet only 25-40% of his crop (grain, fruits etc.) fetches him any money, whereas the rest of his produce (agricultural residues) which constitutes 60-75% of the product is totally wasted and most of the times he has to burn it in the fields.

I know no other industry in the world where 60-75% of the product is not sold or simply junked. No industry can survive on such low productivity. Yet for agriculture we do not think at all about this wastage. This besides the low support price by Government of India has made the farming non-remunerative.

Thus no amount of subsidies or government support price can help the farmers. The only way the farmers can be helped is when they get money for the agricultural residues. This can only happen when these residues can be used to produce energy for powering India. Any marginal farm can produce agricultural residues even if the main food crop fails. On an average a farmer can get an extra income of Rs. 2000-4000/acre from the residues alone if they are used for producing energy. This income can give him benefits even in case of a distress sale of his crop.

India produces ~ 600 million tons of agriculture residues every year. Majority of these are burnt in the fields as a solution to the waste disposal problem since the farmer wants his fields ready for next crop. A small part of the residues may be used for mulching, for fuel (for cooking) or as fodder.

Three types of energy can be produced from these residues. Liquid fuels such as ethanol or pyrolysis oil; gaseous fuels like biogas (methane) and electricity.

Ethanol fuel which can be used as transport fuel can be produced by lignocellulosic conversion of residues into ethanol. Extensive R&D is being done world over to optimize this technology. Few large scale plants in Canada, Japan and U.S. have already been set up on this technology. Nevertheless quite a lot of research still needs to be done to make ethanol production from residues economically viable and environmentally sound. Theoretically the residues in India can produce 156 billion liters of ethanol, which can take care of 42% of India's oil demand for the year 2012.

Pyrolysis oil on the other hand is produced by rapid combustion of biomass and then condensing rapidly the ensuing vapors or smoke to yield oil which is nearly equivalent to diesel. Around 20% of charcoal is also produced as a by-product in the process. The charcoal can be used as cooking fuel for rural households. The pyrolysis oil technology was developed in early 1990s in Europe and North America and is now maturing. Consequently a few plants in Canada, U.S.A. and China have been set up and are producing oil from various agriculture residues. Nevertheless R&D is still needed in producing it economically, improving its keeping quality and making it suitable for use in existing internal combustion engines. Recent experiments in Sweden on running a 5 MW diesel power plant on pyrolysis oil have been successful. India can produce about 400 billion kg of pyrolysis oil from its agricultural residues which is equivalent to 80% of India's total oil demand for 2012.

Similarly these residues can theoretically produce 80,000 MW of electric power year round through biomass-based power plants. This power is nearly 60% of the present installed capacity of India. The power plants could either be small scale (500 kW) running on producer gas from agricultural residues or medium scale (10-20 MW) running on direct combustion of these residues. The technology for this is very mature and there are thousands of such plants running all over the world.

A part of these agricultural residues can also be used via the bio-digester route to produce fertilizer for the crops and methane gas to either run rural transport, irrigation pump sets or for cooking purposes. Yet another stream can also be used for producing fodder for animals. Thus the residues if properly utilized can produce fuel, fodder and fertilizer besides taking care of a huge chunk of India's energy needs. Which stream of residue conversion technology is eventually followed will depend upon the existing market forces.

Energy from agricultural residues in India could be of the order of thirty to fifty thousands crore per year industry. Besides it has the potential of producing 30 million jobs in rural areas.

As the demand for energy increases we may see huge tracts of land coming under energy crops like sugarcane for ethanol production or Jatropha for producing biodiesel etc. This can adversely effect the food production. Already these effects are felt in U.S. where huge acreage has been planted under corn for ethanol production. Similarly very large tracts of land in Brazil are being directed from food production to growing sugarcane for ethanol production. Use of agricultural residues for energy production is therefore the best bet to take care of food vs. fuel debate.

I strongly feel that when the farmers are forgotten, the long term sustainability of the country is threatened. When farms produce both food and fuel then their utility becomes manifold. In India 65% of its population depends on farming for their livelihood and with energy from agriculture as the major focus, India has the potential of becoming a high tech farming community.

Presently the growth of traditional agricultural sector is pegged at 2-3% per year. This low growth is mainly because the agriculture is non-remunerative. If both food and energy is produced from the same piece of land then India's agricultural growth will be rapid and will bring in great wealth to rural areas.

Nimbkar Agricultural Research Institute (NARI)
P.O. Box 44, Phaltan-415523, Maharashtra, India
(E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.)

Published as a Leader Editorial article in Times of India, 6 June 2007.

http://www.nariphaltan.org/farmenergy.htm

Introduction to Alcohol Production

From the pages of HomeDistiller.org

Selections by CS

Distillation
Fermentation
Words of Wisdom
How do I get or make a still?
How do I run a Reflux / Fractionating Still?
Can I run my car on it?
How do I convert between gallons and litres and ....

Distillation - Introduction

Distillation is simply the collection of the ethanol (alcohol) that was made during fermentation. It is the process of heating up the liquid so that it becomes a vapour, then condensing the vapour on a cold surface & collecting it. This works due to the fact that the vapour will contain more alcohol than the liquid it is boil off, because of the different physical properties of water and ethanol. We can then make the vapour more pure by letting it be "stripped" of its water content by passing it up through a packed column which has some condensed vapour running back down through it as liquid. When the two pass each other, the vapour will absorb alcohol from the falling liquid, and the liquid will take some of the water from the vapour. Distilling doesn't "make" the alcohol, nor turn some of it "bad", or into something that will blind you; its only collecting the alcohol that was made during fermentation.

http://homedistiller.org/intro/intro

Fermentation - Introduction

Fermentation is the conversion of sugar to ethanol and carbon dioxide by yeasts (wort to wash). Whilst doing this, it can create a range of flavours beyond what the wort started with. During fermentation yeast converts sugar into alcohol and carbon dioxide by feeding on a series of increasingly complex sugars, essentially breaking the sugar down into other compounds which enable it to grow. First on the menu is glucose, before moving onto maltose, then maltotriose. Depending on the strain of yeast, these sugars may be tackled at different rates, and not always strictly in sequence. Although sugars account for the majority of flavours, yeast works on various other compounds, including amino acids and fatty acids, which also contribute flavours.

Theoretically 10 kg of sugar will produce 6.5 L (5.1 kg) of ethanol and 4.9 kg (4900L) of carbon dioxide. In doing so, some energy is released too (about 2.6 MJ/kg of ethanol).

Yeasts are single-cell fungi organisms. The most important ones used for making ethanol are members of the Saccharomyces genus, bred to give uniform, rapid fermentation and high ethanol yields, and be tollerant to wide ranges of temperature, pH levels, and high ethanol concentrations. Yeasts are facultative organisms - which means that they can live with or without oxygen. In a normal fermentation cycle they use oxygen at the start, then continue to thrive once it has all been used up. It is only during the anaerobic (without oxygen) period that they produce ethanol.

Gil explains ....

More correctly, in the absence of free dissolved oxygen the yeast will continue to breath by scavenging oxygen from the sugar molecules, and by doing so will continue to exhale carbon dioxide but leave the remnant sugar molecule behind in the form of ethyl alcohol.

The yeast does not consume sugar as food, but the other nutrients added to the wort. Mead making is an interesting experiment in this respect since unlike grape juice honey water will not in itself sustain yeast, and any half-decent distiller will do themselves a favour by mastering the technique of making such an environment more friendly.

Over the years I have learned to sustain the yeast in mead batches on a mixture of Vegemite and Epsom Salts, then aerate the wort thoroughly before activating the yeast and pitching. You can experiment with any number of nutrients and aerating systems to breed as much yeast as you want, but I have found the above mix avoids an off-taste in the finished mead and is easy to introduce to the colony.

The process implies two distinct fermentation phases. The primary fermentation takes place as the yeast breeds rapidly in the initially aerobic environment and the colony comes up to strength. Then the secondary fermentation takes place in the anaerobic environment thus generated, as the yeast strips oxygen from the sugar molecules in order to avoid suffocating.

Fermentation does not mean that alcoholic is being produced, only that the wort is in a ferment; that is, bubbling merrily.

Throughout both stages there is an abundance of carbon dioxide being exhaled which assists in maintain the anaerobic environment conductive to the production of ethyl alcohol. It does need to be kept in mind that it is not the yeast colony's intention to produce the alcohol, but ours.

All the yeast is trying to do is avoid suffocating in anaerobic conditions.

Beyond that it is fundamentally misleading to suppose that yeast is much interested in sugar, which can kill it the same as alcohol does, and here we must also recall that we are merely exploiting its ability to adapt to what are essentially hostile conditions.

My reference is A.J. Salle, "Fundamental Principles of Bacteriology", 3rd Edition, New York: McGraw-Hill, 1948.

Another book that must be read is Bill Mollison, "The Permaculture Book of Ferment and Human Nutrition", Tyalgum: Tagari Publications, 1993.

The influence of the yeast depends on the sugar concentration in the wort, the pitching temperature, and the rate of fermentation.

There are three phases to fermentation once the yeast has been added:

1. An initial lag phase, where little appears to be happening, but the yeast is adjusting to its new environment, and beginning to grow in size
2. After about 30 minutes, the yeast begins to reproduce rapidly and the number of yeast cells increases exponentially (thus known as the exponential growth phase). Carbon dioxide is released in large quantities, bubbling up through the liquor. As the fermentation proceeds, the yeast cells tend to cluster together (flocculate).
3. The last phase is a stationary phase during which nutrients are becoming scarce, and the growth rates slow down. The evolution of carbon dioxide slows down, and the yeast settles to the bottom of the fermentor.

Under optimal conditions, a yeast cell is able to split its own mass of glucose (ie about 200 million million molecules) into alcohol and carbon dioxide every second.

For more information about fermentation, see Fermented Fruits and Vegetables - A Global Perspective, and Brewing Yeasts. [Latter url corrected via Wayback Machine 4/1/14 CS]

Yeast produces 33 times more alcohol while reproducing than when resting (so most of the gains are in the first couple of days, then you're just relying on the large numbers of yeast finally present to slowly work their way through the remaining sugars)

Once the nutrients have run out, and the fermentation has become "stuck" or sluggish, it is then too late to provide either nutrients or new yeast. If this happens really early during the fermentation, then you're in trouble. This is because when a yeast is deprived of a nutrient, it grows as best as it can with what is available, and then growth comes to a halt. Those cells are then put together with less than satisfactory levels of (lets say) protein due to deficient nitrogen. Their enzyme content is less than adequate, and they don't metabolize well at all. Growing cells are ~33 x faster at ethanol production than non-growing cells. Supplementation at that point does not re-initiate growth in the older cells. By that time the medium is higher in alcohol and still deficient in some nutrients. Some cells may even have died. Even supplying the combination of BOTH nutrients and new yeast won't get the activity restarted again. So the trick is to ensure you have enough nutrients available at the start of the fermentation.

You end up with having grown about 2g per litre of yeast (eg 40g in a 20L wash) This is why you don't get the full 51.1% conversion of sugar to ethanol, and gives some idea of the amount of nutrients - particularly nitrogen - that you need to supply.

[snip re fusels - CS]

The most common limiting factor for yeast growth is a lack of nitrogen. Nitrogen is approx 9% of the cell mass. Most common form to add it is as the ammonium ion, as the sulphate and phosphate salts (phosphorus is approx 1-2% of the cell mass, and sulfur 0.3-0.5% so these are needed too - this is a nice way of getting all three in there). Add the ammonium phosphate at a rate of 25-50 grams for a 25L wash.

The second most common limiting factor is a lack of oxygen, but it only needs it until high cell numbers are present (eg during the first day) (so make sure that you've aerated the wash well just prior to adding the yeast, but don't do this too much later in the game) "Splash filling" is enough to do the job.

Bacteria can double in number every 20-30 minutes, but yeast takes 3 hours (so guess which one will win the race if an infection gets started and you don't deal to it). Another technique to help with this is to use a lot of yeast - when using Bakers yeast, use at least 150g for a 20L wash. Note that using more yeast wont make the yeast work through to a higher % alcohol, but just enable it to get where its going, faster.

There's a fair bit of choice available as to which yeast to use. I'm personally inclined to use the "Turbo" yeasts, which are pre-packaged with all the nutrients etc necessary. That's because I'm only ever doing sugar-water washes for pure neutral spirits, and I find it easy, convenient, and reliable. I don't try and reuse it a second time, as I only distill every couple of months, and can't be bothered storing it for that long. If however you are doing more of a grain or fruit based mash, and interested in flavours, then consider some of the other yeasts.

How do you know when fermentation has finished? Alex tells ..

You determine the end of fermentation with these signs:

1. There is no more bubbles coming to the surface.
2. There is no more hissing noise inside the vessel.
3. Gravity of the mash sinks equal or below 1.00
4. The mash does not tast sweet anymore.
5. It has been sitting in the bathroom for three weeks.

Hector writes ...

Yeast, as simple a living organism as it is, has some complex nutritional needs, certainly more than just sucrose. However there's a wide variety of yeast strains who's needs differ widely. Alcohol producing strains fall always under the Saccharomyces family, and they, and their metabolic needs and environment adaptation pathways have been the subject of much study. There are "usual" metabolic mechanisms for the fermentation of grape juice, beer wort, et all, by specific members of the Saccharomyces family (e.g. bayanus or capensis in wine, cerevisae and carlsbergensis / uvarum in beer). All of those mechanisms require the presence of their specific sugar and nutrient carrying mediums (grape or apple juice, malt wort, etc.) because their specific yeasts are perfectly adapted to this environments. There's no such thing as an alcohol producing yeast strain that can thrive in such a nutrient deprived medium as a sugar (sucrose) wash. Saccharomyces family strains are all adapted to nutrient rich environments as those cited before, but being that there's no other organism in earth that adapts and mutates as readily and fast as yeast (that's a fact, and it's why yeast is the natural "guinea pig" in cellular death studies that are being advanced right now in the hope of learning to fight cancer), it always finds a way to survive as long as some type of nourishment can be found. This "ways" almost certainly imply a certain loss in the edible qualities of the fermented product because the chemical compounds generated by starving and abused yeasts usually form azeotropic bonds with the ethanol molecule, which is the product you concentrate when you distill an alcohol carrying substance. This compounds are mainly fusel alcohols, esters like amyl and ethyl acetate; diacetyl, acetaldehyde and sulfur compounds like ethyl mercaptin and dimethyl sulfide and disulfide, just to mention the beer (my specialty) pertinent, but universal in this scenario, by-products.

I understand that the much popular ... "turbo" yeast products are no more than specially packaged Saccharomyces strains that include the bare necessities (in nutritional terms) that yeast will need to barely ferment just one sucrose based batch. That's why you guys find the notion of re-pitching your yeast so alien. I believe turbos are a very good thing for the yeast industry and truly they deserved a break. But I find they could try to strike a more consumer wise equilibrium on pricing (IMO they're obscenely expensive). However there's a notion that I believe would make this group improve exponentially their distilled products (and that I haven't read about in any post so far) and it's that whatever you can do to enhance your wash's quality as a fermented product brings by itself a better spirit. I'm no fanatic on this. I don't drink my molasses wines, for instance (though my whiskey's beers are just as good as the product I sell commercially, sans the hops, of course). It's just little things you need to do to avoid the basic problems, like always boiling and quickly cooling the wash, aerating the cooled wash prior to inoculation, keeping the fermentation temp below 23 deg. centigrade, and the original sugar concentration below 17-19° Brix (1.070-1.079 s.g.), and of course, work sanitarily. That's all.

http://homedistiller.org/wash/ferment 

Words of Wisdom

An interesting topic on the newsgroup was one of "if there were just three bits of advice to pass onto someone starting distilling, what would they be ?" [Selected – CS]

Patience + Persistence = Results

1. read every word of "homedistiller.org" at least three times.
2. wait till the enthusiasm wears off a little prior to getting confused/asking questions.
3. ease into it slow & take notes (just like your building your first customized harley)

Fermentation. Sanitize everything involved in the fermentation process. Boil all of the water used to make a mash. Perform aeration (aquarium pump & stone) prior to adding yeast. Use enough yeast. Keep fermenting wash below 30 C, 20 to 25 is better yet.

• Develop a plan to accomplish your goals.
• Ask questions from people who have done it before. Then ask some more questions. 3 people can read a question written by somebody else and see three whole different ways to answer it.
• Avoid buying a whole bunch of expensive fancy equipment until you know that this hobby is what you expected it to be. Lots of equipment can be substituted with less expensive (or free) items. Ask what equipment is absolutely necessary.

Do quite a few sugar washes before attempting grain/mollasses type washes.

Read as much as you can from a wide variety of sources. Get a good book or two with illustrations of how to build and operate a still. Build a small one first, not too large. You can practice your workshop skills. Join a club or news group and LISTEN to all opinions, ask questions, and after awhile, filter out the stuff that you don't believe fits in with the your accumulated experience. Believe in your own abilities, and get on and do it.

http://homedistiller.org/intro/steps/wow

How do I get or make a still ?

Reflux stills can be made from plans on the net, or bought from several manufacturers. For reflux still plans see

• There are 100's of designs in the reflux section, of the forums:
• The photos section for Offset head designs, and this section for general reflux stills.
• Alex's designs at http://groups.yahoo.com/group/Distillers/files/OFTS/
• Ian Smileys "Making Pure Corn Whisky" at http://www.home-distilling.com , with full design details.
• For an excellent book on all aspects of still design, see "The Compleat Distiller" at http://www.amphora-society.com
• See the list of "web resources" below for links to sites selling ready-made stills.
• For fuel alcohol stills see the Mother Earth Alcohol Fuel Manual at http://journeytoforever.org/biofuel_library/ethanol_motherearth/meToC.html, and the The Manual for the Home and Farm Production of Alcohol Fuel by S.W. Mathewson at http://journeytoforever.org/biofuel_library/ethanol_manual/manual_ToC.html. Regarding the choice of heating for the still - if you have 240V available it is usually easiest to control & safer (particularly with internal elements). Gas can be used, but more care is needed to keep the collection container further away and not letting it overfill.
• For more details on design, see Designs and Reflux Design

How do I run a Reflux / Fractionating Still?

See How to Use a Reflux Still for details +/or variations. Also, see this post from the HD forum: LM Still running instructions and a very good how to thread on running an older CM type still is found at: Running a brewshop CM still

Can I run my car on it?

You can run your car on alcohol over about 80% purity. Because any water present will seperate out in the presence of the gasoline (and become a problem), you either need to exclusively use the alcohol, or dry it right out (eg 99%+ purity) if using it to mix with gasoline. See Steve Spences site for more details, the Mother Earth Alcohol Fuel manual, or the The Manual for the Home and Farm Production of Alcohol Fuel. In addition, in the USA, you can get a "small fuel producer" permit, which allows small scale distilling for "motor fuel" purposes. A nice advantage is that they don't require denaturing for "fuel" used on the premises. [Editor's note: This is out of date; see further on this site. CS]

How do I convert between gallons and litres and ....

To convert between SI & Imperial units, multiply the first unit by the conversion factor to get the second. Divide back to do it in reverse .eg 1L = 0.264 US gal, so 20 L = 20 x 0.264 = 5.28 US gal, and 20 US gal / 0.264 = 75.76 L

1 L = 0.264 US gal = 0.221 UK gal
1 L = 1.057 US qt = 0.880 UK qt
1 kg = 2.204 lbm = 32.15 oz (troy) = 35.27 oz (av)
deg F = ((9/5) x deg C )+ 32
1m = 1000 mm = 39.37 inch = 3.28 ft = 1.09 yd

Source: http://homedistiller.org/intro/faq