Mineral and bio fuels

The propane-butane is a mixture of light hydrocarbons – propane (C3H8) and butane (C4H10), which are in gaseous state at atmosphere temperature and pressure. It is derived from deposits of petrol and gas. About 60% from the world production is from deposits of oil and gas, and around 40% is derived at the processing of oil at the refineries. It finds application as motor fuel, and as a combustion product for household use.

Automotive gasoline is toxic, transparent and yellow-tinted liquid. It is mixture produced at boiling at low temperature oil products and are mainly used as fuel for internal combustion engines. Their chemical composition contains mainly aliphatic hydrocarbons, produced by fractional distillation of petroleum.

Low octane gasoline products are reinforced by isooctane or aromatic hydrocarbons, toluene and benzene for increasing the octane. Small amounts of various additives are common, for engine tuning or lowering the harmful emissions from poisonous gases. The volume of sulphur is lower than 10 mg/kg.

Kerosene is a flammable hydrocarbon liquid. It is used as jet engine fuel. It is produced from primary kerosene distilled fractions, which have undergone additional hydro treating.

The mineral diesel fuel is a product of the distillation of petroleum at temperature between 200 °C and 360 °C at atmosphere pressure. Its chemical components are carbon chains, which usually contain between 8 and 21 carbon atoms in each molecule. It is designed for burning in diesel internal combustion engines in all kinds of self-propelled vehicles. The content of sulphur cannot be

Gas oil is liquid fuel of petroleum origin. It is characterised by at least 65 percentage of its volume is distilled at 250 °C and accordingly at least 85% recovery at 350°С. It is designed for stationary combustion installations for industrial and communal purposes in accordance with application. Gas oils are used for propulsion of all kinds of non-road vehicles, machinery, inland waterways ships, and recreational craft. The sulphur content cannot be more than 10 mg/kg.

Boiler fuel is a heavy oil fraction, which is obtained after distillation of gasoline, kerosene and gas oil (diesel) fractions. It looks like dense and non-transparent, dark-brown liquid. Depending on the physiochemical properties of oil from which it is obtained and its purpose, the mazut is classified as oil, lubricants, fuel, paraffin. In the refineries it is used as a raw material for producing lubricating oil or light oil extraction by cracking (petrol, diesel, kerosene). It is also used as fuel in power plant boilers or for heating in industrial boilers, as well as diesel fuel in powerful slow-moving engines, especially in the navy.

The road bitumens are exclusively obtained by distillation process of specific selection of crude oils. Bitumen is the glue, which is used for joining of non-organic components as sand, crushed stones, rubble and limestone powder at asphalt laying. To guarantee the longevity and stability of the pavements when applying the finishing asphalt coating, a modified petroleum bitumen with added butadiene and styrene is used.

Biodiesel is a fuel produced by biological resources different from petroleum. Biodiesel can be produced from vegetable oils – soy, rapeseed, and sunflower as well as from animal fats and it is used in automobile and other engines.

It is considered as the most perspective and ecologically clean fuel. Biodiesel improves the work of the engine, increasing its power, it does not contain sulphur and reduces the fuel consumption. Biodiesel can be used as pure biodiesel (indicated B100) or it could be mixed with mineral diesel at different ratios and it is suitable for the majority of the modern diesel engines. From 2012 the Bulgarian legislation provides a minimum volume of 6% biocomponent (indicated B6).

There are two principle approaches for biodiesel production.

• The first relies on several consecutive chemical treatments of the initial raw oil. During these, ethyl or methyl esters of the fatty acids are produced. The chemical process is always connected with the production of glycerine and of other by-products. The quality of the that glycerine is low and it should be neutralized, as it is pollutant.

To avoid the described problems oil-based biofuel could be used by technology B.

• In the second approach physiochemical and physical processing of the feedstock is being used. It does not require special stationary installation. It does not involve processes using toxic chemical reagents. This technology is used to produce biofuel only and it there are no pollutant by-products.

Bioethanol is a substitute for the traditional petrol. It is produced by corn, barley, sugar cane and others. According the renewable sources energy law the content of bioethanol in the automotive gasoline should reach 9% (Indication B9) in 2016.

Bioethanol is a renewable source energy, a substitute or supplement to the traditional petroleum. The bioethanol is not only characterized with higher octane and provides accordingly more effective work of the engine, but also produces less harmful emissions in the atmosphere. The Bioethanol does not contain toxic components and sulphur and it is produced by waste-free process.

At combustion the bioethanol does not produce greenhouse gases, smell or smoke, but only water vapour and carbon dioxide as every live fire. The combustion of 1 litre bioethanol produces carbon dioxide equal to the quantity produced when burning two big candles.