Ethanol Fuel Pros and Cons

November 8, 2013

Ethanol fuel is a highly touted alternative to gasoline, but while it's "green", it's not necessarily more efficient in all contexts.

Ethanol Plant

Many vehicles now use ethanol fuel. If you look at the production process, you might easily mistake it for a brewery and you would not be too far from the truth. The process involves fermentation, distillation and dehydration as a means of finally extracting the fuel as a refined product.

What It's Made From
Ethanol is mainly a natural product and comes from crops such as corn, grain and sugar cane. This makes it highly sustainable in an environment where energy conscious producers are being pushed to steer away from fossil fuels. In a sustainable crop there is enough space to grow food crops as well as fuel crops and it could be highly advantageous to farmers in the coming years. All natural by products of these crops can be transformed into some sort of bio-fuel to benefit the masses and sustain green living.

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The Production Process
The process of creating ethanol as a fuel begins with microbial fermentation of natural sugars. Before this process can begin, some products need to undergo a process of saccharification. This process converts the natural carbohydrates, like starch and cellulose, into sugar by means of enzymes. As with alcohol production, these sugars are then distilled. Once this process is complete, the process of dehydration takes place.

Distilling the Mixture
In order for ethanol to become a viable fuel, the water within its structure has to be removed. Distillation will remove most of it, but it reduces the purity to around 96 percent. This lowers the effectiveness, so further processes must be undergone in order to create a more pure version. Therefore, dehydration is another stage by which the process is furthered to produce the end product.

The Dehydration Process
Dehydration consists of five basic stages to completely eliminate the from the azeotropic ethanol water mix. The initial process is called "azeotropic distilling," in which cyclohexane and benzene are added. This combination creates a heterogeneous azeotropic mix of a vapor/liquid/liquid mixture. When this is distilled it causes the production of anhydrous ethanol. It also produces vaporous mix of cyclohexane, benzene and water, which, when condensed, transforms into a two part liquid. From there a ternary component is added in order to increase the volatility of the ethanol.

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Environmental Concerns
Ethanol fuel plants should pay special attention to energy saving policies. This has lead some companies to look at ways of reducing the processing costs as well as the environmental impact. Some have become proponents of cutting out the distilling process in favor of simple dehydration. This requires the use of sieves to molecularly eliminate the water from ethanol fuel. There are many other methods being researched and considered in order to make the process simpler, shorter and less expensive, but these are still under review.

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Ethanol Fuel Pros and Cons

The U.S. and Brazil are the biggest consumers and producers of ethanol fuel. Many U.S. vehicles on the road today are flexible-fuel vehicles, which are capable of running on a mixture of gasoline and ethanol. Most flexible-fuel vehicles in the U.S. allow 10 percent ethanol and 90 percent gasoline blends. In Brazil, many cars run on E85 ethanol fuel, or 85 percent ethanol. Due to pressure to become energy independent and more environmentally aware, alternative fuels like ethanol have become a significant source of fuel. There are, of course, advantages and disadvantages to ethanol fuel.

Greener Fuel Production
Ethanol production creates less greenhouse emissions than other fuels. The production process includes cultivation, which requires diesel powered equipment that emits pollution. The process also involves distilling or separating water from alcohol, which usually uses coal-generating electrical energy. But producing ethanol from corn instead of gasoline reduces greenhouse emissions by 13 percent, according to researchers. This reduction can also be increased in the future by improving technology and using sources like switchgrass instead.

Positive Energy Balance
Many critics of ethanol believe that it takes more energy to produce ethanol than it delivers as a fuel. The reason being that ethanol decreases the mileage of a car. However, a study reveals that ethanol fuel from corn creates a positive energy balance. The production of ethanol creates several by-products and valuable products like corn oil.

Fluctuating Price
The price to fill up on ethanol varies greatly and fluctuates differently from gasoline. In the past, ethanol has sold for almost 30 cents less per gallon compared to regular gasoline. However, ethanol has also sold for 80 cents more than gasoline. These price changes and differences are usually due to regional location. For example, ethanol is likely to be cheaper in the Midwest where more corn is being grown.

Lower Mileage
Ethanol naturally holds less energy than gasoline. The unfortunate result is decreased mileage by 20 to 30 percent for vehicles running on the alternative fuel. For people who live in areas where ethanol is pricier, gasoline may be especially cheaper to buy. However, there are engine technologies that lessen this mileage effect and are found in some flexible-fuel vehicles.

Poor Infrastructure
There is a lack of ethanol production facilities for the fuel to become more widely used. As a result, there is also a lack of ethanol fueling stations. The majority of these stations are found in the Midwest where ethanol production is highest. Many drivers who have flexible-fuel automobiles are only filling up on gasoline instead of the fuel mixture. It's evident that more distribution and production is needed before ethanol can become as accessible as conventional gasoline.

How an Ethanol Fuel Cell Works

An ethanol fuel cell is an alternative to a traditional internal combustion engine. In a fuel cell, the fuel conversion rate is 40 to 50 percent, compared to 15 to 20 percent with an internal combustion engine. Because the membrane of the cell must be kept clean, the logical fuel choice is clean, hydrated ethanol.

A fuel cell can be compared to a battery. In a fuel cell there are two electrodes, an anode and a cathode, separated by a proton exchange membrane. The anode on one end acts as the positive end and the cathode on the other end acts as the negative end. One side contains a hydrogen based fuel, in this case ethanol, and the other is oxygen-based. Surrounding the proton exchange membrane is an electrolyte catalyst. When the fuel and oxygen pass through the electrolytes and are mixed, energy is produced. As long as the fuel is replenished, the cell will continue to produce energy until such time as the membrane or catalyst becomes too dirty or damaged to continue the production.

Where They're Used
Ethanol fuel cells are still in development, but they can be used to power cars and trucks. The more advanced the technology, the more prevalent cells will become. They can also be used to power other transportation sources, including scooters, buses, trains and planes, and hospitals, businesses and office buildings. The applications are endless and growing daily. Industry goals have fuel cells eventually being used much like batteries are now, powering cell phones, laptops and other types of communication technologies.

Why Ethanol Fuel Cells Are Important
Clean fuel technology, flex-fuel cars and trucks, development of biodiesels, decreased dependence on fossil fuels; all of these technologies are paving the way for the United States to end its dependency on fossil fuels. Included in these technologies is the use of ethanol as a fuel or a fuel additive. As our need for fuel and energy sources increases, the push to develop technologies like the ethanol fuel cell grows, in order to create energy production and transportation that is cleaner to operate and sustainable.

Methanol vs. Ethanol
Both methanol and ethanol fuel are among greener alternatives to gasoline. Both offer less dependence on fossil fuels, and use, in part at least, sustainable materials as their source. Which of them offers the better solution as a fuel?

It's cheaper to produce methanol fuel than it is to produce ethanol fuel. That gives it a distinct advantage. A greater variety of materials, both biomass materials and coal and natural gas can be exploited to make methanol, whereas ethanol is essentially grain alcohol, also known as moonshine. In terms of safety, methanol and ethanol fuel aren't equal at all. Methanol is a great deal safer, largely due to the fact that it's far less flammable. On the side of ethanol, it's far less toxic than methanol.

Methanol contains only 67 percent of the energy of gasoline per gallon, while ethanol has 75 percent of gasoline's energy per gallon. What this means is that neither manages the same mileage per gallon. That figure is offset by the fact that they're cheaper to produce. They manage a much greater mileage per dollar. As gas prices continue to increase, methanol and ethanol fuel become much better deals.

Methanol fuel does need additives to work in a car engine, otherwise it can cause corrosion. Ethanol fuel, on the other hand, can work in a standard gasoline engine without any adjustment. If the engine has been modified to run methanol, it will also be able to run ethanol or regular gas.

Green Qualities
Both methanol and ethanol fuel are biodegradable and will dissolve in contact with water. This makes them a much better option for the environment than gasoline. It should be noted, however, that as ethanol is produced from plant matter, you need to factor in the energy expended in the growth of those plants. When broken down, ethanol is nowhere near as green as its proponents claim. It takes far more energy to produce a single gallon of ethanol than it does to produce a gallon of methanol, as almost anything can be used to produce that. To supply the nation's fuel needs with ethanol would mean turning over all the farm land to the production of corn, which could be used to make it, and that's not a feasible solution.

E85 Ethanol
E85 Ethanol is a mix of ethanol and gasoline. It's 85 percent ethanol and 15 percent gasoline. It burns more cleanly than gasoline, and helps stretch the finite supply of gas further. However, the mileage in a car isn't as good a regular gas. The gain in air pollution is offset by the lack of mileage, making for an awkward tradeoff, with methanol still out ahead as a fuel.

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