The beneficial properties of oil have been known to mankind since time immemorial. It is used to produce fuel and raw materials for the production of synthetic fibers and plastics. At the same time, humanity has always sought to maximize the benefits derived from the processing of fossil fuels. One of these methods was catalytic reforming - a process that gave rise to high-quality gasolines and aromatic hydrocarbons.
This method of oil refining was invented back in 1911, and since 1939 the technology has been applied on an industrial scale. Since then, the distillation method of natural fuels has been continuously improved. Today it is one of the most complex and effective ways to produce high octane gasoline.
Fuel distillation
Catalytic reforming is the process of dehydrogenation (cleavage of a hydrogen molecule from organic compounds) of six-membered naphthenes in the presence of nickel and some other platinum group metals at high temperature, which leads to the formation of aromatic compounds. In other words, this is a process that allows you to get a high-octane product - reformate - from low-quality raw materials - straight-run gasolines.
The main reason that reforming has become so widespread is the concern for the environment. Prior to this, lead-based antiknock agents were used to produce high octane gasoline. When reforming, emissions are virtually absent.
Received Products
Using this technology, it is possible to extract the most valuable petrochemical raw materials - benzene, toluene, aromatic hydrocarbons. Today, catalytic reforming is a process by which up to 480 million tons of petrochemical products per year are produced worldwide.
The main end product of the production cycle is reformate - gasoline with an octane rating of 93-102.
At the same time, by-products arise - paraffin hydrocarbons, as well as 90% hydrogen gas, which is the purest than obtained by other methods.
Another product accompanying catalytic reforming is coke. He, precipitating on the surface of the catalysts, significantly reduces their activity. They are trying to reduce its quantity.
Catalytic reforming technology
The raw material for catalytic reforming is straight-run gasoline - a fuel with a low octane rating. The whole process is carried out in 3-4 reactors that have a fixed catalyst bed. The reactors are interconnected by pipes with a complex multi-chamber system and heating of the transition product.
Catalytic reforming catalysts are a carrier - alumina (A1203) interspersed with platinum crystals. In reactors at a temperature of 480-520 ° C and a pressure of 1.2 to 4 MPa, the feed is converted to high-octane isoparaffin and aromatic compounds.
Very often, to increase the stability of the process, more expensive metals (rhenium, germanium, iridium), as well as halogens - chlorine and fluorine are introduced into the technology.
Types of Catalytic Reforming
To date, many invented methods for producing high-octane gasoline and aromatic hydrocarbons through catalytic reforming reactions. Each foreign company keeps its own production method a secret. However, they are all based on three main methods:
- Oil reforming, carried out simultaneously in three to four reactors continuously. Its essence lies in the fact that the process catalyst first fully develops its potential, after which the reactors stop until the accelerator regains its properties.
- Continuous reaction in 2-3 plants - the reagent is periodically restored in each system as it develops. At the same time, the process does not stop, and the regenerating reactor is replaced by a “floating", additional one.
The greatest productivity can be achieved with a continuous reaction using regenerative plants and reactors. The catalyst, as its properties deteriorate, is placed in a regenerating chamber, and in its place comes a “recently recovered reagent,” aluminum-platinum compounds circulate.
Main problem
The main problem that accompanies reforming is the formation of a large amount of coke, which reduces the catalytic ability of aluminoplatinum materials. The solution to this problem is to burn coke deposits on the surface of the reacting elements using an oxygen-inert mixture at a temperature of 300-500 degrees Celsius. This process in the scientific community is called regeneration.
It is impossible to completely restore the catalytic element. As it exploits, it irretrievably ages, and then goes to special factories, where platinum and other expensive metals are extracted from it.
Catalytic Reform Reactors
This method of processing natural fuels is carried out by various types of plants. We will name a few of them:
- Selectoforming. Here, the reforming unit combines the catalytic dehydrogenation process with selective hydrocracking.
- Platforming It has 3 reactors in its composition, and the operation time of the catalysts is from 6 to 12 months.
- Ultraforming. One of the first installations with a "floating" reactor, which carries out the process of reagent recovery.
- Isoplus. Reforming and thermal cracking processes are combined to produce the product.
Oil reforming is most widespread in North America - it processes up to 180 million tons of natural fuel annually. In second place are the countries of Europe - they account for about 93 million tons. Russia closes the top three with an annual production of about 50 million tons of oil.