Catalytic cracking of oil (in translation from English - splitting) - the technological process aimed at increasing the yield of gasoline by special processing of the components of heavy oil fractions.When the primary processing of the product is obtained in 5-14% of the average total weight of the gasoline.The quality of the fuel after the straight-run does not satisfy the requirements of modern technology.
catalytic cracking increases gasoline yield and improves its quality.
are two types of thermal (catalytic) cracking: liquid and gas phase.For the first feedstock is a heavy oil, which is fed into a furnace at 600-625 ° C under a pressure close to atmospheric.The gas-phase catalytic cracking is carried out under the same conditions, but it is a raw material for gas oil (solar oil).In the thermal cracking in the structure of high-carbon alkane broken links and form molecules of low molecular weight hydrocarbons included in the gasoline fraction:
S10N22 - S5N12 + S5N10.
Thus, the dean of the high formation of two substances (saturated and unsaturated hydrocarbons) lower molecular weight.
catalytic cracking is carried out in the presence of catalyst (activated clay or aluminosilicates) at a temperature of 470-530 C under a pressure of from 70 to 370 kPa.The main raw material for the process is a gas oil, gasoline yield with the total weight of the oil may reach 30-40%.Therefore, the production of gasoline - it is difficult and time-consuming process.To improve the quality of the product is removed from its structure alkenes and alkynes, which sometimes take up 30% of the total weight.
Through the use of innovative technologies, the yield of gasoline during the distillation of crude oil can be up to 80 percent.To assess the quality of liquid fuel are octane.As a fuel sample with high anti-knock properties was chosen isooctane or 2,2,4-trimethylpentane.
its octane rating is considered equal to 100. As the sample with the lowest anti-knock properties take n-heptane: S7N16, the octane number (RON), which is considered equal to 0. In order to determine this indicator compared to the properties of the detonation properties of a mixture of gasoline with octane and nheptane.
For example, a product with an octane number of 80 has the same detonation properties, such as a mixture of 80% isooctane and 20% n-heptane.The higher the octane number, the higher the quality of the fuel.Increase of fuel economy and keeps the power of internal combustion engines.The product is added, and other components, including hydrocarbons and synthetic origin, and antiknock (substances that are at the minimum concentrations (no greater than 0.5%) improve antiknock properties of the fuel).Previously used for these purposes tetraetilplyumbum.Due to the fact that the substance is very toxic, it was replaced by other antiknock, which are made of margantsevoorganicheskih connections.These substances are less toxic to our body and make it possible to produce fuel with octane one hundred and twenty five hundred and thirty units.
gasoline production technology
by direct distillation of the oil obtained from the gasoline octane to 91. The method for today - a luxury, because the yield of gasoline is low.To increase the yield and to improve the fuel quality used redistillation, catalytic, thermal cracking, reforming, etc.
These methods increase the cost of labor, time and money, however, only they give less harmful to the environment gasoline.To increase the octane of today often use a variety of chemicals (alcohols, organometallic compounds, ethers, etc.).
