Biofuel

Already in the 1940s, the first steps were taken to utilize biogas for vehicle operation in Sweden. The biogas was collected from to example, digested manure and then used as fuel in the vehicles that could also run on gangrene, a gas mixture that mixes other contained carbon monoxide and hydrogen gas and obtained by incomplete combustion of charcoal. In recent years, biogas has begun used as a vehicle fuel on a larger scale. Sweden is today (2004) the country that lies at the front of this development. PREPARATION OF THE GAS Vehicle operation requires relatively large efforts on the treatment side. First, must energy value is increased by upgrading, that is, separation of carbon dioxide. Also water and pollutants that can be corrosive or environmentally and health hazardous example, hydrogen sulfide is removed. Particles must also removed so that mechanical disturbances does not occur. Finally, it is required that the gas be compressed, that is, pressurized, before use. Producing fuel from biogas is therefore, in the initial stage, relatively costly, as it requires both treatment facilities and a functioning infrastructure with enough gas vehicles and refueling points. Biogas's environmental benefits do yet this fuel increases in importance. Its environmental benefits are also utilized maximum when used as a replacement for gasoline or diesel for vehicle operation. One Government inquiry (The Swedish National Fire Commissioner SOU 1996: 184) has appointed biogas to the most environmentally friendly propellant in competition with electricity, ethanol and rapeseed methyl ester

VEHICLE Vehicle technology is the same as for natural gas and upgraded biogas can be refilled together with natural gas. Cars that can Run on biogas and natural gas are so called two-fuel cars (bi-fuel), that is, they are equipped with two separate tanks for gasoline respective gas. The same engine is used for both fuels and the car can be easily connected to gasoline operation if the gas should run out. This is an advantage since the number of filling stations with gas pump is still limited. The Most models start on gasoline and hit automatically switch to gas operation after some seconds. Heavy vehicles like buses and on the other hand, trucks built for gas operation adapted to driving only on this fuel. In gas operation, the otto process is always used, which gives the engine slightly different properties than when a diesel engine used. Among other things, a heavier engine is required gas operation and fuel consumption are slightly higher. The most common way to store gas in vehicles are in pressure tanks at about 200 bar pressure. Because the biogas has a relatively low density (volume weight), the tank becomes quite space-consuming, but nowadays the idea is integrated into

the vehicle in such a way that it does not intrude on cargo or passenger spaces. The relative short range of a gas tank (about 25 - 40 miles) makes heavy vehicles that only can be run on gas is best suited for shorter ones mileage, for example in city traffic k. The first Swedish passenger car for methane gas was launched in 1996, a Volvo 850 bi-fuel. Today, gas cars are manufactured in a number of different ways models. A gas-powered vehicle costs on the order of 10-20% more than the equivalent standard vehicle. For many of the alternatives however, the fuel, your biogas, counts State governments economic instruments examples in the form of subsidies and lower fuel taxes, which may be stimulate increased use in the future.

REFUELING Upgraded biogas for vehicle operation can is distributed to the filling station via a pipeline directly from the biogas plant, mixed up with natural gas via the gas network or with help of a container system where pressurized biogas to be filled in, etc., which is replaced when the gas runs out. Refueling is as fast as when refueling of gasoline or diesel. For buses in city traffic k There are also filling stations intended for so-called long-term remuneration, which has a lower investment cost, since they do not need to be so large compressor capacity. Refueling takes here 5-20 hours and usually takes place at night. The general filling stations providing Vehicle gas is still the closest in the south and western Götaland, but new gas stations built in different parts of the country. The number of biogas cars that roll on our roads increases in pace with fl and fl are fitted with gas pump. A current list of different gas stations for gas in Sweden can be collected from The Environment Agency's website, www.miljofordon.se.

The emissions of dust and particles in the environment are negligible in gas operation. The exhaust also does not contain pollutants such as benzene or toluene. The exhausts smell less and the gas engine is quieter and vibrates less than a diesel engine, which makes the noise reduces. This is not least important when driving with heavy vehicles in city traffic. The emissions of carbon monoxide, hydrocarbons, sulfur compounds and nitrogen oxides are lower than at petrol and diesel operation. Strict requirements on those traditional fuels along with Improved engine technology also contributes to emissions from petrol and diesel vehicles are now decreasing. However, when it comes to climate impact, the biogas has a clear advantage since its combustion does not any addition of greenhouse gases to the atmosphere. Methane is a safer fuel than gasoline and diesel as the gas is not toxic and lighter than air. Should a leak occur the gas rises rapidly upwards and diluted in the surrounding air. The gas tank's robustness construction also means that it can withstand much more stress than a conventional gas tank.