Crude oil is extracted from the Earth’s surface; the oil contains hydrocarbon compounds which are made up of carbon and hydrogen atoms in a specific ratio. The number of carbon and hydrogen atoms characterizes the size, length and property of the hydrocarbon chain. When being refined the hydrocarbon groups that have the same molecule size are separated based on the difference in their boiling points. There are three steps in the refining process, separation, conversion and purification. In the separation process, the crude oil is filled in a fractional distillation Colum, and then heated to a specific temperature. When separation is complete high amounts of diesel is converted from the to diesel fuel. The diesel is made pure by reacting it with a catalyst which expose it to hydrogen under controlled conditions.
Hydrocarbon chain.
Petroleum refining process… The first part of the refining process for petroleum happens in a crude oil distillation centre, when the crude oil is withdrawn from the ground it is send to the distillation centre where it is separated into different ranges regarding to its boiling temperature. The distillation process is normally referred to as the atmospheric distillation centre as the process usually operates above atmospheric pressure. The incoming crude oil is then preheated when passing the heated liquid in the other stages of the process, it is then desalted which is the process where they remove all of the sodium chloride ‘inorganic salts’. After the de-salting process is complete the liquid is then reheated by the other hotter streams of liquid and is then put into a fire heater to heat it up to a temperature of around 398 degrees, it is then routed to the bottom of the distillation tower. The cooling of the distillation tower is partially completed by heat exchange from heated liquids and incoming crude oils, it can also be cooled by and air cooled or water cooled condenser system. There is also a pump around system which can be used to reduce even more heat from the tower. If any of the liquid over heats during this process it is then sent off to other regions of the centre and i s stored for further processing, this substance is called naphtha and also maybe pure gas, anything below the specified temperature is separated into other substances like kerosene, diesel, lubricating oil, heavy gas oil and residual.
Petroleum - motor fuel •liquid •mix of alkanes and cycloalkanes (5 to 12 carbon atoms) •boiling range = 104 to 401 degrees Fahrenheit / 40 to 205 degrees Celsius
The differences between petrol and diesel Petrol -A mixture of alkanes and cycloalkanes with about 5 to 12 carbon atoms -The boiling point for distillation is about 40 to 205 degrees Celsius -Octane rating, this is the amount of pressure the fuel can width stand during the compression stroke before ignition, the octane also reduces knock when starting. -Petrol burns hotter; this means less energy is going to drive the wheels. - Calorific value is 45.8 mega joules per kilogram -less dense -roughly 33.7 mega joules of power produced per letter. Diesel -Alkanes containing 12 or more carbon atoms. -Boiling point for distillation is 250 to 350 degrees Celsius -Cetane rating, the higher the cetane rating the easier it will be to combust. -Burns cooler, more power going to the wheels and less heat produced -Calorific value 45.5 mega joules per kilograms - Diesel is denser -15% more power, roughly 36.9 mega joules per letter