At present, humanity faces three main problems: reducing greenhouse gas emissions into the atmosphere, obtaining alternative fuels and increasing soil fertility. And the second and third problems are closely interrelated. So a promising source of energy is biofuel, for the production of which currently grown technical crops, which removes agricultural land from the rotation and ultimately leads to higher food prices.
On the other hand, the development of industry leads to an increase in greenhouse gas emissions, an increase in their concentration in the atmosphere leads to climate change, drought and, ultimately, crop reduction.
All these phenomena are observed against the background of an increase in the population of the Earth. Thus, a vicious circle is obtained: increasing production – increasing energy consumption – increasing greenhouse gas emissions – using biofuels – removing from the turnover of land for technical crops – reducing yield and rising food prices.
Biofuel is a fuel from biological raw materials, obtained, as a rule, by processing stalks of sugar cane or rape seeds, corn, soy.
At present, critics studying the development of the biofuel industry say that the growing demand for biofuels forces agricultural producers to cut crop areas under food crops and redistribute them in favor of fuel. For example, when producing ethanol from fodder corn, a bard is formed – a waste of ethanol production. It is used to produce mixed fodders for livestock and poultry. In the production of biodiesel from soybeans or rapeseed, cake is used, which is used for the production of mixed fodder for livestock. That is, the production of biofuel creates another stage of processing of agricultural raw materials.
According to economists from the University of Minnesota, as a result of the biofuel boom, the number of hungry people on the planet will increase to 1.2 billion by 2025.
In Indonesia and Malaysia, a large part of the rainforest was cut down to create palm plantations. The reason was the race for the production of biodiesel – fuel, created on the basis of vegetable or animal fats, as an alternative to diesel fuel (rapeseed oil as fuel can be used in pure form).
Low cost and low energy costs are what are needed to produce alternative fuels from semi-technical oilseeds.
On the one hand, the increase in acreage under technical maize varieties will result in the employment of fertile land suitable for the production of food products. On the other – according to Bank of America Merrill Lynch estimates, the cessation of biofuel production will lead to an increase in prices for oil and gasoline by 15%. But consumers, especially in poor developing countries, will face a double blow if prices for both food and oil prices rise. According to the World Bank estimates, in 2009 2.7 billion people in the world lived less than two US dollars a day, and even a slight increase in the cost of major cereal crops would be a disaster for them.
Thus, it is necessary to look for other ways of obtaining ethanol (bioethanol).
At present, several technologies for biofuel production have been developed and successfully applied. The main ones are the following:
production of fuel from agricultural waste;
Adding biological components to traditional fuels;
chemical synthesis of fuel.
In the case of obtaining biofuel from agricultural waste, the raw materials are plant residues and manure. Wastes are dried and heated to a temperature of 400-500 on S. Of precipitated by this treatment gas fractions obtained high quality diesel fuel, devoid of harmful impurities. The resulting diesel fuel is neutral with respect to CO 2 , since the combustion of such fuel releases as much carbon dioxide as was absorbed in the growth of plants. The purity of such biological solar oil meets the most stringent standards. According to experts, agriculture of only European countries can provide up to 80% of modern requirements for diesel fuel.
To improve the ecological characteristics of fuels, biological components such as rapeseed oil are added therein. If up to 30% of rapeseed oil is added to diesel fuel, then its ecological characteristics improve significantly, and the energy characteristics remain practically unchanged. It is also important that such biofuel can be used in traditional internal combustion engines.
Chemical synthesis of gasolines and diesel fuels is very energy-intensive. Typically, the raw material for this method of producing fuel is wood. Changing the parameters of the technological process, from wood, you can get various types of fuel, from aviation gasolines to diesel fuels. Synthetic fuel has good environmental performance. When it burns, no harmful substances are formed, it is neutral with respect to CO 2 . Due to high energy costs and complexity of technological processes, synthetic fuel is very expensive.
In the European Union countries, thanks to government support, the production of diesel fuel with biological additives increased more than 5 times and reached 10 million tons. Worldwide biofuel production has increased more than 2.5 times during this period.
As biological additives, derivatives derived from vegetable oils obtained from sunflower, rape, soybean and other oilseeds are used. Oils for biofuel are obtained by spinning and extraction with subsequent purification. The heat of combustion of pure bio-additives to biofuel is close to the heat of combustion of the diesel fuel itself.
It is noteworthy that soybean is used as raw material for biofuel production in the USA and Brazil, and in Europe more than 75% of biodiesel is obtained from rape. By 2020, in the countries of the European Union, the share of bioadditives to diesel fuel will be brought up to 20%. The US and China by this time will bring the percentage of bioadditives to 40%.
Currently, most of the bioethanol is produced from corn (USA) and sugar cane (Brazil). Raw materials for the production of bioethanol can also be various crops with a high content of starch or sugar: manioc, potatoes, sugar beets, sweet potato, sorghum, barley, etc. Ethanol can be produced in large quantities from cellulose. Raw materials can be various waste from agriculture and forestry: wheat straw, rice straw, bagasse of sugar cane, sawdust, etc.
Thus, at present too many crop areas are occupied by technical varieties of agricultural plants. This leads to an increase in food prices. From such plants biofuel – ethanol is received. It is necessary to find new methods for obtaining ethanol.
Ethanol (ethyl alcohol), which is usually called simply alcohol, is formed during so-called alcoholic fermentation. Many types of sugars, as well as the product of saccharification of starch in the presence of malt, are cleaved under the action of microscopically small yeast fungi, with the formation of alcohol and carbon dioxide.
Everyone who has ever seen fruit juice wander, watched the intensive release of carbon dioxide from a branch pipe. Because alcohol fermentation can occur spontaneously, dilute alcohol is known to people from ancient times as an exciting drink. It’s hardly necessary to talk about the harmful consequences of drunkenness.
The alcohol content during fermentation of solutions of sugar and fruit juices varies widely. However, since yeast fungi can not exist at a high alcohol concentration, no more than 15% alcohol can be produced by fermentation. The more concentrated alcohol is obtained from the diluted solutions by distillation.
Fermentation is a rapidly expanding decomposition of organic matter, caused by microorganisms, to which this process serves as a source of kinetic energy.
When alcoholic fermentation the simple sugars are decomposed into ethyl alcohol, C0 2 and heat:
With 6 ? 12 ? 6 = 2? 2 ? 5 ?? + 2?0 2 + 28 calories.
A typical organism that causes alcoholic fermentation is unicellular ascomycete mushrooms from the genus Saccharomyces. In addition, alcoholic fermentation is also caused by some mucoral fungi and many bacteria. All normal breathing under air higher and lower plants in the absence of oxygen to form a certain amount of alcohol and C0 2 . In alcohol fermentation of yeast, in addition to normal fermentation products, ethyl alcohol and C0 2 , a small amount of by-products is formed, namely, acetic aldehyde, acetic acid, glycerin, succinic acid, malic acid and so-called fusel oils.
In addition to the aforementioned yeast, it is reasonable to use medusomycete (Medusomyces Gisevi) – a symbiosis of acetic acid bacteria and several yeast species.
In Russia, it is possible to find production waste containing small amounts of sugar (sugar-containing waste). If you try to use them to get biofuel, then it is possible to increase its share without additional material costs.
If it is possible to obtain ethanol with the help of a fungus from waste, rather than from agricultural crops, it will be possible to reduce the acreage under technical crops and cheaper foodstuffs, which in turn will lead to economic growth.