From Ecopedia

Overview

Diesel Fuel a type of power source that is derived from various sources such as petroleum, natural gas, coal, vegetable oil, and animal fats.^[1] This type of fuel is used in internal combustion engines and typically has a much greater torque output than generic gasoline. It is commonly used to power some automobiles, generators, and heavy machinery and transportation vehicles such as ships, semi-trucks, and construction equipment.

Diesel fuel may also be referred to as Petroleum diesel or Petrodiesel, which is also produced from fossil fuel sources such as coal and natural gas, though it is developed using crude oil distillation.^[2]

In addition to Petrodiesel, other types of Diesel Fuel exist including Biomass to liquid diesel (BTL), Biodiesel, Gas to liquid diesel (GTL), and Clean Diesel Fuel (CDL) or Ultra-low Sulfur Diesel (ULSD).^[3][4]

Petroleum Diesel Vs Gasoline

Compared to Gasoline, petroleum diesel is about 18% denser. Also, diesel refining from petroleum is much simpler than from gasoline.

Unlike gasoline, petrodiesel is highly efficient and provide additional torque, besides exhibiting lower explosiveness and inflammability, a reason why most military vehicles including trucks and tanks run on petrodiesel.

However, a major disadvantage in using petrodiesel is the fuel’s inability to quickly start in cold weathers due to viscosity fluctuations. Another disadvantage of diesel-fueled engines is the possibility of the engine’s runaway failure because of the fact that diesel fueled-engines support non-spark ignition and can sustain operation only and until diesel is supplied.

Environmental Impacts

Sulfur Emissions

Conventional petrodiesels contain high sulfur content, which is found to severely harm the environment. Sulfur content in diesel would typically prevent the use of catalytic filters that control diesel particulate emissions. In addition, Sulfur emissions coming from diesel fueled-automobiles cause environmentally-hazardous acid rains.

In an attempt to minimize sulfur emissions, many alternative non-petroleum based diesel fuels such as biodiesel or most earth-friendly ULSD clean diesels are increasingly promoted by the environment-governing bodies.

ULSD is an ultra-clean, highly refined low-sulfur content diesel. Sulfur content in ULSD fuel is 15 ppm (parts per million) or even less. Compared to the standard high-way use diesel fuels, ULSD is 97% cleaner. In the US, EPA (Environmental Protection Agency) made it mandatory for all highway diesel fuels to meet the 15ppm sulfur standard. The leading automobile manufacturer, Mercedes-Benz was the first automaker to release passenger vehicles powered by ULSD diesel fuel.

Chemical Pollutants

Most of the petroleum-derived diesel fuels are composed of approximately 75% of saturated hydrocarbons, primarily including paraffinsm, and 25% of aromatic hydrocarbons that include alkylbenzenes and naphthalenes.

Microbe Contamination

Diesel fuels provide suitable medium for certain microbes like algae to survive and feed on the fuel. Increased growth of microbe population would eventually lead to clogging of fuel lines as well as fuel filters. Biocide treatment is the only solution for treating such contamination.

Diesel Spills

Diesel spills, a common occurrence on roads, would severely affect tire grip as well as traction, causing many road accidents.

Green Diesels

In order to reduce the toxic sulfur emissions, many alternative diesel fuels such as synthetic diesel, biodiesel and ULSD are introduced into the fuel market. Synthetic diesels made from hemp, wood, corn, garbage, food scraps, sewage-sludge or straw through synthetic gasification and purification. Such synthetically produced diesels ensure 30% lower emissions of particulates as against conventional petrodiesels.^[5]

Biodiesels, on the other hand, are derived from eco-friendly vegetable or animal sources. Biodiesels are extremely useful in the event of any fuel spills, as biodiesel is less-toxic and gets easily washed away with water unlike other fuels.

Both sulfate and sulfur oxide emissions that cause the deadly acid rains, are effectively eliminated with biodiesel. Moreover, pure biodiesel fuels contribute to substantial reductions in unburned hydrocarbons, particulate matter or carbon monoxide as against petrodiesel or gasoline fuels.^[6]

References

1. ↑ http://en.wikipedia.org/wiki/Diesel_fuel
2. ↑ http://en.wikipedia.org/wiki/Diesel_fuel
3. ↑ http://en.wikipedia.org/wiki/Diesel_fuel
4. ↑ http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/how-clean-diesel-fuel-works.htm
5. ↑ http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/how-clean-diesel-fuel-works.htm
6. ↑ http://www.uop.com/renewables/10010.html