In the publication it is a question of alternative types of fuel for autotractor engines. Need of their development and application for internal combustion engines is caused by fast reduction of stocks of oil in the earth and deterioration of an ecological situation in many countries Alternative to usual fuel today is natural gas the methane, the liquefied gas propane-butane, alcohols (methanol and a standard) biofuel, dimetilovy air, and also hydrogen.
DIESEL CHANGE
Alternative types of fuel for autotractor engines
The alternative come to replacement to fuel from oil. Need of their development and application for internal combustion engines of autotractor equipment is caused by fast reduction of stocks of oil in Earth and deterioration of an ecological situation in many countries, first of all the developed.
Oil stocks in a subsoil of Earth are limited, costs of its getting and transportation constantly increase and, under condition of preservation of modern growth rates of production and consumption, explored reserves of oil will suffice only for 40-50 years.
Today oil is almost uniform source of production of motor fuel for which receiving about 50 % (1,7 billion t from 3,5) oil which is extracted therefore practically in all countries searches of substitutes of oil types of fuel are conducted are spent.
Tractors pollutants
The autotractor equipment, and especially motor transport, is one of the biggest sources of environmental pollution in the majority of the countries of the world – it is the share of its share from 50 to 60 % in total amount of emissions, and in big cities this figure reaches 80-90 % and more.
Alternative – planet health
It is conventional that application of alternative fuel reduces contents of toxic substances (carbon dioxide – CO2, nitrogen oxides – NOx, carbohydrate – SnNm) in exhaust gases of autotractor equipment. However among experts there is no consensus concerning extent of decrease in harm.
Alternative to usual fuel today is natural gas the methane, the liquefied gas propane-butane, alcohols (methanol and ethanol), biofuel, dimetilovy air, and also hydrogen.
Natural gas
The main component of natural gas is methane (CH4). Use of natural gas as alternative fuel for an internal combustion engine possible in such directions: the compressed (komprimovanny) natural gas (SPG); the liquefied natural gas (SPG); processing of natural gas in liquid oil products (the so-called GTL technology – gas to liquid – gas in liquid) which can be used as motor fuel or its components.
Today more than in 50 countries of the world works on zavmene oil fuel on the compressed natural gas became more active. First of all it is caused by that it has high octane rating (110-115 units by results of researches, allows to use it in engines with extent of compression 10-12. Contents of toxic substances in exhaust gases in 1,5-2 times are lower against exhaust gases of petrol engines. Gas has no liquid phase in an air-gas mix which excludes washing off of wooden oil from walls of cylinders, as a result the resource of operation of the engine increases in 1,4-2 times, and replacement of wooden oil is carried out to 2-2,5 times less often. Methane is characterized by rather low ozonoobrazuyushchy potential and owing to the chemical inertness doesn’t take participation in photochemical reactions of formation of a smog.
The main lack of the compressed natural gas as motor fuel consists in smaller warmth of combustion which leads to reduction of run of the car on one filling approximately in 2 times and decrease in engine capacity for 9-14 %. However it is possible to eliminate it by means of increase of extent of compression in the chamber of combustion or injecting fuel it is direct in the combustion chamber, or applying a turbo-supercharging.
Abroad the tendency to use on autotractor equipment of the liquefied natural gas was outlined. Feature of its use consists that temperature of boiling of such gas – a minus 162°S. And it creates certain difficulties at its receiving and storage. But 20 summer experience of the American company "Mask" which lets out automobile engines for this type of fuel, shows that these difficulties can be overcome.
CTL technology
This technology is realized at present only according to the scheme of prime receiving synthesis gas (a mix of oxide of carbon and hydrogen) on the basis of which carry out synthesis of methanol and a mix of hydrocarbons. The methanol received from sintza-gas and a mix of hydrocarbons are processed further in different motor fuel or its components.
The liquefied oil gas
The main components of the liquefied oil gas (CIS) are propane and the butane which contents depend on fuel brand. On the to properties it comes nearer to gasoline that caused its effective use in petrol engines.
The main obstacle for a growth in volumes of use of the CIS is need of creation of a network of fillings and the high prices for the gazobalonny equipment.
Spirit fuel
Among low-molecular alcohols as motor fuel found application only methyl and ethyl. It in considerable volumes speaks their productions and high detonation properties.
However, because their warmth of combustion is almost twice lower than in carbohydrate fuel, application of such fuel is limited. Unpopularity of alcohols is influenced also by other factors. Low pressure of saturated steam and high warmth of a vyparyvaniye complicates, and sometimes and does impossible, engine start-up at low temperatures. Alcohols have high corrosion activity which amplifies in the presence of water, as they hygroscopic.
Therefore much more often these alcohols are used as an additive to hydrocarbonic types of fuel. Such mixing of fuel, with a certain fate of convention, it is possible to carry to the alternative.
Dimetilovy air (DME)
According to experts, nowadays it is the most perspective alternative fuel for diesel engines. Raw materials for its receiving is natural gas.
Among positive operational properties of dimetilovy air, first of all, it is necessary to note high cetanove number (55-60 units) and completeness of combustion which provides practical absence in the chamber of combustion of a deposit and sazhisty parts in exhaust gases.
As fuels it is possible to carry to DME shortcomings in 1,5 times smaller temperature of combustion that leads to increase in expenses of air in 1,5-1,6 times, low kinematic viscosity (more than at 20-30 time smaller, in comparison with diesel fuel), and also very low lubricant properties.
Biofuel
Biological call motor fuel which receive with renewable, generally vegetative, raw materials sources. To them carry bioethanol – ethyl alcohol (hydrolytic and food) from vegetative raw materials, a biodiesel engine – biodiesel fuel and so-called fuel of a R-series.
Biodiesel engine. For its production use different olive cultures (a soya, a rape, etc.), and also industrial wastes of animal fats. Oil subject to hydrolysis therefore receive glycerin and a mix of fat acids. This mix eterificiruyut methanol with receiving methyl fat acids – biodiesel fuel which can be used in pure form or in the form of different compositions with traditional diesel fuel.
The fuel of a R-series developed at Princeton university (USA), represents an ethanol mix, metiltetragidrofurana, C5 hydrocarbons. This fuel passed wide tests which finished that behind ecological properties R-series fuel much more surpasses oil gasolines.
Hydrogen fuel
Interest to hydrogen as to motor fuel big, after all at its combustion in the engine obrazovyvaetsya water and in this regard it is most environmentally friendly fuel. The temperature of its combustion in 2,5 times is higher in comparison with gasoline, and a source of raw materials for receiving hydrogen – almost boundless.
As fuel it can be used both directly hydrogen, and hydrogen together with traditional fuels. It can be applied and in fuel elements.
The main problem of use of hydrogen is its storage onboard power means. So, it is offered to contain it in the form of the compressed gas or the liquefied hydrogen. One of solutions of this problem is use of carriers of hydrogen in the form of hydrides of metals or other carriers.
Practice shows that the best indicators are provided at storage of the liquefied hydrogen.
Technical difficulties when using and high cost of hydrogen led gasoline-hydrogen to development of the combined fuel. The carried-out tests showed that use of benzino-hydrogen mixes allows to lower twice a consumption of gasoline on speeds of 90-120 km/h and on 28 % – at movement in the city.
In recent years a lot of attention is allocated for development and use on motor transport of fuel elements fuel for which is hydrogen or the products, capable to allocate it when processing.
Fuel elements – it devices which develop electric energy at the expense of energy of oxidizing and renewable chemical reaction of liquid or gaseous reagents which continuously arrive in electrodes from the outside, i.e. they are chemical sources of a current of continuous action. The greatest distribution was received by hydrogen-oxygen fuel elements.
Work of a hydrogen-oxygen fuel element is based on transformation of energy of chemical reaction of hydrogen with oxygen in the electric. Thus hydrogen from a tank moves on "anode" of a fuel element, oxygen – on "cathode". In the presence of the catalyst (platinum) atoms of hydrogen are split on protons and electrons which different ways get on "cathode". The Ionnoobmenny membrane passes protons, forcing electrons to pass through an electric contour and incorporates to protons on the cathode. The electric current arising in a chain is used for an electric motor drive before the atom of hydrogen which was formed on the cathode, will incorporate to oxygen in a water molecule. Heat and water is by-products of this reaction. Each fuel element develops electric energy tension about 0,6 Century. The connected 200-700 fuel elements provide necessary capacity within 50-75 kw.
The car with fuel elements which work at hydrogen, sterilely pure: instead of exhaust gases - pure water.
(On Agrosektor magazine materials).