Text/Mite Polymer milan only
Now international price of crude oil is down to $20/bbl, why is domestic price of gasoline down only a few cents? We know that oil is still a highly demanded commodity on world market, and not only its core part is very valuable in refining process. At same time, some of its additional materials may also play a role, so it still has a very significant price in international market, and we know that not all parts of oil can be used when it is in crude oil stage. . Regarding quality of crude oil and impact of refining process, composition ratio of refined gasoline and diesel fuel will also vary. At present, refining ratio of crude oil in world is between 40% and 80%. The level of refinement is probably in middle stage, around 60%. Take our well-known Sinopec for example, in 2017, Sinopec refined about 239 million tons of crude oil and produced about 151 million tons of refined oil, gasoline grew by 1.2% year on year, and there was no production. an increase of 5.5%, but diesel fuel decreased by 0.9% compared to it, and share of refined oil is about 63%. We can say that level of travel in international market is still in lead.
Currently, after processing these crude oils, resulting waste can still be used for other purposes. In addition to production of these direct-use petroleum products, residues can also be used to produce some chemical raw materials. , such as ethylene, propylene butadiene, etc. It is a chemical raw material that is widely used in various industries, and can also be used in lubricants, asphalt and paraffin in manufacture of other products. From road construction to small plastic items used in our homes, it's entirely possible that they originated from oil refinery waste.
In general, otherwise, it is very understandable why these countries only export crude oil and do not process crude oil, because not only can there be losses in refining process, but also a mature refining technology is required. useful, otherwise, with this technology, not only is processing rate very low, which is more uneconomical than sale of crude oil, but you also need to bear a lot of intermediate costs. Some developed countries can even recycle crude oil at a rate of 80%, while many backward countries, although their domestic oil reserves are very rich, their refining rate is only about 40%, so they recycle their refined oil. oil, profit that can be made is not necessarily more than direct sales of crude oil, which is why many countries in Middle East are very rich, because they have their own ideas and think it is better to sell directly than to sell. process yourself Crude oil is more profitable.The main route from crude oil to oil is usually:
①Crude oil is first separated into various straight-run distillate oils according to boiling point requirements of various products, and then imperfect components in these distillate oils are removed according to standard product quality requirements;< /p>
② As a result of transformation of chemical reaction, necessary components are formed, and then a number of qualified petroleum products are obtained.
Commonly used refinery processes are atmospheric and vacuum distillation, catalytic cracking, delayed coking, hydrocracking, solvent deasphalting, hydrotreating and catalytic reforming.Atmospheric and vacuum distillation 1. Raw material: crude oil, etc. 2. Products: naphtha, gas oil (gas oil), fuel oil, asphalt, minus line.
Atmospheric and vacuum distillation is collective name for atmospheric distillation and vacuum distillation, which is basically a physical process: crude oil is separated into petroleum products (called fractions) with different boiling point ranges in a distillation column depending on evaporation. Some of these oils, after mixing and adding additives, leave factory in form of products, and a large part is raw material for subsequent processing of devices.
Atmospheric vacuum distillation is first oil refining process in refineries, called primary crude oil refining, which includes three processes: a) desalination and dehydration of crude oil, b) atmospheric distillation, c) vacuum distillation.
Only 10-40% of light oil products such as gasoline, kerosene and diesel fuel can be obtained from conventional crude oil by atmospheric and vacuum distillation, and rest is heavy distillate and residual oil. If more light oils are required, heavy distillates and residues must be recycled. Catalytic cracking is most commonly used process for production of gasoline and diesel, and gasoline and diesel are mainly produced by this process. It is also most important production link of general oil refining and chemical enterprises.
1. Raw material:
Residual oil and wax oil account for about 70%. Vacuum distillate oil and coking wax oil are commonly used as feedstock for catalytic cracking. However, with growth of crude oil and increase in demand for light oil, most chemical companies have begun to add vacuum residues to feedstock and even directly use atmospheric residues as raw materials for refining.
Gasoline, diesel fuel, slurry oil (heavy distillate oil), liquid propylene and liquefied petroleum gas; gasoline accounts for 42%, diesel fuel accounts for 21.5%, propylene accounts for 5.8%, and liquefied petroleum gas accounts for 8%. , and oil sludge accounts for 12%.
Coking (called coking) is a deep thermal cracking process and one of ways to handle oil residues. This is only process that can produce petroleum coke and cannot be replaced by any other process. In particular, special need for high quality petroleum coke in some industries has led to fact that coking process has taken an important place in oil refining industry. In coking, hydrogen-depleted heavy residual oil is used as feedstock.oil (such as vacuum residue, cracked residue and bitumen) and a deep thermal cracking reaction occurs at high temperature (400-500°C). According to cracking reaction, part of residual oil is converted into gaseous hydrocarbons and light oil products, by condensation reaction, another part of residual oil is converted into coke. On one hand, since raw material is heavy and contains a significant amount of aromatics, on other hand, coking reaction conditions are more severe, so condensation reaction makes a larger proportion, and more coke is generated.
1. Raw material:
Delayed coking is a decarbonization process similar to catalytic cracking to change ratio of carbon and hydrogen in oil. The feedstock for delayed coking can be heavy oil, residual oil, or even asphalt, and feedstock quality requirements are relatively low. . The main processes for processing fuel oil are delayed coking and hydrocracking.
Main products: wax oil, diesel fuel, coke, naphtha and some gases 16%, gas 7-10%, external oil 1-3%.
The basic principle of lightening heavy oil is to change relative molecular weight and ratio of hydrogen and carbon in oil, and relative molecular weight and ratio of hydrogen and carbon often change simultaneously. There are two ways to change hydrogen-carbon ratio of petroleum products: decarburization and hydrogenation. Hydrocracking refers to process of hydrogenation of oil refining process, which consists in adding hydrogen from outside in presence of a catalyst to increase ratio of hydrogen to carbon in oil.
Hydrocracking is an organic combination of hydrogenation and catalytic cracking processes. On one hand, it can convert heavy oil products into light oil products such as gasoline, kerosene and diesel fuel through cracking reactions. Catalytic cracking produces large amounts of coke. , and impurities of sulfur, chlorine and oxygen compounds in feed can also be removed by hydrogenation to saturate olefins.
1. Raw material: heavy oil, etc.
2. Products: Light oils (gasoline, kerosene, diesel or catalytic cracking, feedstock for olefin cracking)
Solvent deasphalting is a pretreatment process for low grade residues. The extraction method is used to remove colloids and bitumen from vacuum residue obtained from distillation of crude oil (sometimes from atmospheric residue), to produce oil deasphalted oil and obtain petroleum bitumen. Solvent deasphalting is a refining process for refining heavy oil. This process uses heavy oil as raw material such as vacuuma large residue, and propane, butane and other hydrocarbons are used as solvents for extraction. The extract is deasphalted oil. lubricating oil feedstock or cracking feedstock, and raffinate defatted asphalt can be used as road asphalt or other uses.
1. Feedstock:heavy oil such as vacuum or atmospheric residue
2. Products: deasphalted oil, etc.
Hydrotreating usually refers to processing of certain petroleum products that cannot meet requirements of use, through a hydrogenation process, in order to achieve specified efficiency indicators. The hydrotreating process is a general term for catalytic refining of various petroleum products under pressure of hydrogen. It refers to hydrogenolysis reaction of various non-hydrocarbon compounds in oil under conditions of a certain temperature and pressure, catalyst and hydrogen, and then removed from oil to achieve purpose of oil purification.
Hydrotreating is mainly used for refining petroleum products, and its main purpose is to improve performance of petroleum products through refining.
1. Raw material:
Gasoline, diesel fuel, kerosene, lubricating oil, petroleum wax, etc., which contain more harmful impurities such as sulfur, oxygen and nitrogen.
Refined and modified gasoline, diesel fuel, kerosene, lubricating oils, petroleum wax and other products.
Reformation: transformation of hydrocarbon molecules into new molecular structures.
Catalytic reformer: as raw materials use straight-run gasoline (i.e. naphtha) or blended oil from recycled gasoline, under action of a catalyst (platinum or polymetallic), undergo dehydrocyclization and hydrocracking. Reactions such as isomerization and isomerization to convert hydrocarbon molecules into new molecular structures with primary purpose of producing C6-C9 aromatics or high octane gasoline, and using hydrogen reforming by-product for thermal cracking secondary treatment, delayed coking gasoline or diesel hydrotreating.
1. Raw material:
Naphtha (light gasoline, chemical light oil, stable light oil)
High-octane gasoline, benzene, toluene, xylene and other products (these products are main raw materials for production of synthetic plastics, synthetic rubber, synthetic fibers, etc.), as well as a large amount of secondary hydrogen.