Comprehensive coverage

A simple method for obtaining biodiesel

Since the US wants to reduce its dependence on imported oil, it is expected that biodiesel fuels will play an important role in this goal. According to the National Renewable Energy Laboratory, a unit of the US Department of Energy, biodiesel "is a significant energy resource and could supply 5-3% of the petroleum distillate market in the future."

Brown University researchers Aaron Socha (left) and Jason Slough demonstrate the biodiesel production process
Brown University researchers Aaron Socha (left) and Jason Slough demonstrate the biodiesel production process

One of the main obstacles to achieving this goal is finding the method to efficiently convert the abundance of waste vegetable oil (for example, the waste oil used to fry falafel and fries) into biodiesel fuel. The existing methods are lengthy, expensive and ineffective. Worse, the process requires the use of the toxic chemicals phosphoric acid and potassium/sodium hydroxide.

Two chemists from Brown University (USA) describe in an article, recently published in the scientific journal Organic & Biomolecular Chemistry, how they managed to convert waste vegetable oil into biodiesel in a single reaction vessel using environmentally friendly catalysts. Their process is also six times faster than current methods of converting waste vegetable oil into biodiesel, so it uses less energy.

"We wanted to develop a technically simple and environmentally friendly method for converting waste vegetable oil to biodiesel," said the lead researcher, a professor of chemistry at the university.

Waste vegetable oil consists of triacylglycerols (free fatty acids) and water. The conventional method of converting waste vegetable oil to biodiesel requires two separate reactions. The first reaction converts the free fatty acids into biodiesel, but this conversion requires the use of phosphoric acid. The second reaction converts the triglycerides to biodiesel, but this conversion requires the use of potassium/sodium hydroxide. These two reactants cannot act together, so the reactions must be carried out in separate vessels. This constraint makes the process less efficient.

In order to find a better method, the researchers began to examine catalysts that would be cheap, chemically stable and have limited toxicity. Finally, they focused on the materials bismuth triplet and scandium triplet, which are common in organic chemistry as chemical catalysts. In addition, they performed the reactions using a microwave device instead of a heating oven. They found that the new catalysts converted the waste vegetable oil into biodiesel in about twenty minutes, while with existing methods the process takes about two hours. Although the new method requires a higher temperature - 150 degrees Celsius compared to 60 degrees Celsius in the usual methods - it consumes less energy cumulatively since the reaction is much faster.

The chemists were also able to perform the conversion in a single reaction vessel, since the catalysts are able to promote both types of reactions. In addition, the researchers reported that the catalysts used in the conversion of the free fatty acids, which are the more challenging catalysts for the development of the two reactions, were suitable for five cycles of activity, while maintaining a reaction utilization of 97 percent. The ability to recycle the catalysts reduces their cost and minimizes the damage to the environment, the researchers point out.

"Although we have not yet proven the utility of our approach on an industrial scale," says the lead researcher, "we have identified highly promising catalysts and reaction conditions that could, in principle, be used in the industrial conversion of waste vegetable oil to biodiesel in an environmentally friendly manner."

The news about the study

3 תגובות

  1. Apart from politics, at the top of our survival concerns - the ecology.

    We are worried about the state of the Amazon, greenhouse gases, environmental pollution, the ozone layer and the depletion of sex, and of course the purity of our bodies, the purity of the air, water and food.

    There is a complete and exclusive consensus in our collective consciousness that the main threat to our existence and our economy is posed by carbon fuels. We all wonder if it is even possible to reduce the burning rate and who knows what we have already done.

    The fuel industry invests vigorously in continuing to train the spreader of pollution through a global strategy according to which most car manufacturers are already working to convert the industry and the market to the "trend" of hybrid vehicles in order to preserve the use of carbon fuels on the one hand, while at the same time perpetuating a "green" illusion in the public mind.

    The problem inherent in this approach lies not only in the toxicity of the batteries to the environment, but also in the subsequent increase in fossil fuel emissions from the power plants. It is patently clear that salvation will not come from hybrid vehicles. The smoke of the so-called ecological electric scooters is now emitted from the power stations instead of Rothschild. Big deal.

    We must focus our attention and efforts on reducing carbon dioxide emissions and there is no denying that cleantech is a global, effective and coordinated first effort designed to finally begin to deal with the problem, however the essential breakthroughs are still far in the future. The gas that Israel won will perhaps allow it to pollute less from the power plants, clean up a bit and perhaps improve the balance of points and bonuses, but the life expectancy of humanity depends to a large extent on its ability to wean itself off carbon for energy needs and reconcile with the environment with the benign and friendly hydrogen (hydrogen).

    Hydrogen can be produced in many different ways, all in their infancy and still prohibitively expensive or impractical. The existing technologies for producing hydrogen require a lot of external energy, up to 75% of its cost today as car fuel. The car manufacturers have long been polishing their eyes for the hydrogen age, but for now its production involves impossible costs that only Nissan and a handful of fans in California and three (3) hydrogen gas stations manage to run in the meantime.

    Hydrogen, the lightest and most common chemical element in the universe (90%), is also the most efficient and cleanest fuel that nature offers us (it is three and a half times more energy intensive than coal, gasoline, diesel, etc.). Experimental vehicles powered by hydrogen have already been developed and are already being marketed (in expensive leasing). Others are still on the drawing tables of the major car companies planning the cars of the future. Power plants that will generate electricity by burning hydrogen are also in advanced planning stages since burning hydrogen almost does not cause environmental pollution. The main problem that stands between us and the realization of this technological vision is not the programming of the hydrogen production, but the price of its production.

    The most available source of hydrogen is water (a water molecule contains two hydrogen atoms and one oxygen atom) but in order to break the water molecule into its components, water must be heated to a very high temperature under low pressure. Under these conditions, the hydrogen atoms separate from the oxygen atoms, but when the mixture gradually cools, the hydrogen and oxygen return and form water. It goes without saying that the cost of the energy invested is 75% of the cost of the fuel for these gasoline cars.

    The technology that appears to have the highest technological economic programming is the most brilliant and the simplest.

    It turns out that it is possible by easy, simple and clean fermentation of coli and clostridium bacterial cultures (pathogenically free of course) on a substrate of garbage grinding residues, agricultural waste, or of course clean sugar, in order to produce enough hydrogen cheaply. For example, in the absence of oxygen, certain bacteria convert carbohydrates and acids into hydrogen. Purple bacteria that use light to produce energy by photosynthesis emit hydrogen to break down acidic molecules.

    I wish we all get this ultimate fuel. It is already attainable, will be sustainable and will increase health.

    And what is most beautiful, we will produce it ourselves in the home reactor or refuel at the neighborhood facility or landfill.

    Nissan is going for the revolution. We can only hope for its success.

    Even the word hydrogen is pleasing to the ear in Hebrew.

    Happy Holidays to everyone. How symbolic - the purification of the temple.

  2. The paragraph beginning with the words vegetable oil waste consists of triacylglycerols is not translated correctly, instead of brackets should come commas, instead of nitric acid the acid is phosphoric acid
    In the third sentence in the paragraph, the error is in the source and the reaction converts the free acids to biodiesel and not the triacylglycerols as written in the source.
    Besides, an excellent article like all the articles on the site and also like all the articles by Dr. Moshe Nachmani. Well done.

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.