CN114702982A

CN114702982A - Process for preparing olefin by crude oil one-step full fraction cracking

Info

Publication number: CN114702982A
Application number: CN202210213502.7A
Authority: CN
Inventors: 姚日远; 肖传慰; 陈祥; 袁卫; 黄常青
Original assignee: Yangzhou Petrochemical Co ltd
Current assignee: Yangzhou Petrochemical Co ltd
Priority date: 2022-03-04
Filing date: 2022-03-04
Publication date: 2022-07-05

Abstract

The invention discloses a process for preparing olefin by cracking full fractions of crude oil by a one-step method, in particular relates to the technical field of petroleum olefin cracking, and comprises the following steps: the method comprises the following steps: preparing raw oil, and dividing the raw oil into different straight-run distillate oil according to the boiling point requirements of different products; step two: placing a granular catalyst in a reactor to form a static catalyst bed layer, and then supplementing hydrogen from the outside in the presence of the catalyst to improve the hydrogen-carbon ratio of the oil product; step three: heating and boosting raw oil and hydrogen, and enabling the raw oil and the hydrogen to enter a reaction system after the raw oil and the hydrogen reach reaction conditions through heating and boosting; step four: firstly, hydrofining is carried out to remove sulfur, nitrogen, oxygen impurities and alkadiene, and then hydrocracking reaction is carried out; step five: cooling, separating, depressurizing and fractionating the reaction product, and then sending the product out of the device to separate out gas with higher hydrogen content to be used as recycle hydrogen; step six: the unconverted oil may be partially recycled, fully recycled or not recycled in one pass.

Description

Process for preparing olefin by crude oil one-step full fraction cracking

Technical Field

The invention relates to the technical field of petroleum olefin cracking, in particular to a process for preparing olefin by cracking whole fractions of crude oil in a one-step method.

Background

The petroleum olefin cracking device mainly produces ethylene, co-produces propylene and carbon four-fraction, and obtains butadiene through extraction by a Dimethylformamide (DMF) or acetonitrile method; the carbon five and the carbon nine of the pyrolysis gasoline which is a byproduct are cut off, and the rest carbon six to carbon eight fractions are hydrogenated by two sections to obtain the hydrogenated pyrolysis gasoline; it contains more aromatic hydrocarbons, generally up to 60% or more, and can be extracted to obtain benzene, toluene and xylene.

The raw materials used for producing ethylene range widely from the lightest ethane to the heaviest vacuum diesel (some to be hydrogenated and saturated), including natural gas condensate (NGL), Liquefied Petroleum Gas (LPG), Naphtha (NAP) and atmospheric diesel (AGO), even hydrogenated heavy diesel (VGO), etc.; the ethylene yield or the total yield of triene and triphenyl is different along with the change of the raw material source; the general rule is that the raw material hydrocarbon has high ethylene yield; the ethane feed from NGL is generally considered to be optimal since the final ethylene yield can be as high as around 80%; the quality of a cracked feedstock was evaluated as measured by the hydrocarbon composition of the feedstock (typically expressed in terms of PONA values; P, 0, N, A represent respectively alkanes (Paraffin), alkenes (Olefin), cycloalkanes (naphene), aromatics, hydrogen content, relative density, and aromatics character in heavy oil (BCMI).

In the petrochemical production process, a petroleum fractionation product (including petroleum gas) is used as a raw material, and the temperature (700-800 ℃, sometimes even higher than 1000 ℃) higher than cracking is adopted to break the hydrocarbon with long-chain molecules into various short-chain gaseous hydrocarbons and a small amount of liquid hydrocarbons, so as to provide an organic chemical raw material. This process is known in the industry as petroleum cracking. Cracking is therefore said to be deep cracking, and petroleum processing processes based on short chain unsaturated hydrocarbons are chemical changes.

The preparation of olefin by one-step whole fraction cracking of crude oil in the prior art has the following problems:

at present, in order to fully utilize crude oil resources and improve the yield of low-carbon olefins, various hydrocarbon raw materials are generally cracked into olefins by a cracking furnace through steam cracking, the commonly used cracking furnace comprises a convection section and a radiation section, the crude oil contains high-molecular-weight nonvolatile components with the boiling point exceeding 590 ℃, when the convection section of the conventional cracking furnace is preheated, a small part of the nonvolatile components are not gasified, the unvaporized nonvolatile components are entrained to the radiation section along with mixed gas flow, coking deposition of the radiation section is easily caused, even the radiation section is blocked, and the yield of cracked products is influenced; to this end, we propose a process for preparing olefins by full-cut cracking of crude oil in one step, which solves the above problems.

Disclosure of Invention

The invention aims to provide a process for preparing olefin by cracking a whole fraction of crude oil in a one-step method, so as to solve the problems in the background technology.

In order to solve the technical problem, the invention adopts the following technical scheme: a process for preparing olefin by cracking a whole fraction of crude oil in a one-step method comprises the following steps:

the method comprises the following steps: preparing raw oil, and cutting the raw oil into different straight-run distillate oil according to the boiling point requirements of different products.

Step two: the granular catalyst is placed in a reactor to form a static catalyst bed layer, and then hydrogen is supplemented from the outside in the presence of the catalyst to improve the hydrogen-carbon ratio of the oil product.

Step three: heating and boosting raw oil and hydrogen, and enabling the raw oil and the hydrogen to enter a reaction system after the raw oil and the hydrogen reach reaction conditions through heating and boosting.

Step four: firstly, hydrofining is carried out to remove sulfur, nitrogen, oxygen impurities and dialkene, and then hydrocracking reaction is carried out.

Step five: after the reaction product is cooled, separated, depressurized and fractionated, the target product is sent out of the device, and gas with high hydrogen content (80 percent and 90 percent) is separated out and used as recycle hydrogen.

Step six: the unconverted oil (called tail oil) can be partially circulated, fully circulated or not circulated once through.

Preferably, the raw oil in the step one is heavy oil.

Preferably, the temperature rise in the third step is about 400-450 ℃.

Preferably, the pressure for raising the temperature and the pressure in the third step is 10-15 MPa (100-150 atm), and about 400 ℃.

Preferably, the catalyst in step two is an oxidation catalyst, a hydrogenation catalyst, a dehydrogenation catalyst, a hydroformylation catalyst or a polymerization catalyst.

Compared with the prior art, the invention has the beneficial effects that:

the invention belongs to a hydrogenation route of petroleum processing through hydrocracking, and the hydrogen is supplemented from the outside in the presence of a catalyst to improve the hydrogen-carbon ratio of an oil product; hydrocracking is essentially an organic combination of hydrogenation and catalytic cracking processes, on one hand, heavy oil can be converted into light oil such as gasoline, kerosene and diesel oil through cracking reaction, on the other hand, a large amount of coke can be prevented from being generated like catalytic cracking, and sulfur, chlorine and oxygen compound impurities in raw materials can be removed through hydrogenation to saturate olefins; the fluidized bed reaction process with a plurality of reaction zones can better control the reaction temperature and improve the stability of the process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram of an integrated crude oil one-step whole fraction cracking process for olefin production according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

The embodiment is as follows: as shown in figure 1, the invention provides a process for preparing olefin by cracking a whole fraction of crude oil in a one-step method, which comprises the following steps:

The method comprises the following steps: preparing raw oil, and cutting the raw oil into different straight-run distillate oils according to the boiling point requirements of different products.

Further, the raw oil in the step one is heavy oil.

Furthermore, the temperature rise in the third step is about 400-450 ℃.

Furthermore, the pressure for raising temperature and pressure in the third step is 10-15 MPa (100-150 atm), and about 400 ℃.

Further, the catalyst in the second step is an oxidation catalyst, a hydrogenation catalyst, a dehydrogenation catalyst, a hydroformylation catalyst or a polymerization catalyst.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The process for preparing the olefin by cracking the whole fraction of the crude oil through a one-step method is characterized by comprising the following steps of:

2. The process for preparing olefins by crude oil one-step whole fraction cracking as claimed in claim 1, wherein the raw oil in the first step is heavy oil.

3. The process for preparing olefin by cracking the whole fraction of the crude oil in the one-step method as claimed in claim 1, wherein the temperature rise in the third step is about 400-450 ℃.

4. The process for preparing olefin by cracking the whole fraction of the crude oil through the one-step method as claimed in claim 1, wherein the pressure for raising the temperature and the pressure in the third step is 10-15 MPa (100-150 atm) and about 400 ℃.

5. The process for preparing olefins by the one-step whole fraction cracking of crude oil as claimed in claim 1, wherein the catalyst in the second step is an oxidation catalyst, a hydrogenation catalyst, a dehydrogenation catalyst, a hydroformylation catalyst or a polymerization catalyst.