CN108179028B

CN108179028B - Heavy oil processing method and system

Info

Publication number: CN108179028B
Application number: CN201711419863.2A
Authority: CN
Inventors: 王洪彬; 郑应绪; 黄新龙; 张婧帆; 庞晓飞; 亚飞; 冯凌; 周文琳; 张国库
Original assignee: Sinopec Engineering Group Co Ltd
Current assignee: Sinopec Engineering Group Co Ltd
Priority date: 2017-12-25
Filing date: 2017-12-25
Publication date: 2020-03-31
Anticipated expiration: 2037-12-25
Also published as: CN108179028A

Abstract

The invention provides a heavy oil processing method and a heavy oil processing system. A method of processing heavy oil comprising the steps of: step A: enabling hydrogen-rich gas and a heavy oil raw material to react in a low-temperature cold plasma reactor to generate a first product; the weight ratio of the hydrogen-rich gas to the heavy oil raw material is 0.001-0.2: 1, preferably 0.005-0.15: 1; and B: subjecting the first product to delayed coking to produce a second product; and C: and fractionating the gas-liquid phase component in the second product to obtain products with different fractions. The invention is based on the unique activity of the plasma, and the plasma is used for strengthening the traditional delayed coking reaction process to activate the raw oil, thereby improving the yield of the liquid oil.

Description

Heavy oil processing method and system

Technical Field

The invention relates to the technical field of chemical industry, in particular to a heavy oil processing method and system.

Background

With the decreasing world petroleum resources, crude oil shows the tendency of heavy oil and deterioration, and the proportion of heavy oil (atmospheric residue and vacuum residue) generated in the processing process is higher and higher. How to improve the comprehensive utilization efficiency of the existing resources, especially heavy oil, has become a great problem to be solved urgently by the oil refining industry.

The traditional heavy oil processing technology mainly comprises two processes of hydrogenation and decarburization.

The heavy oil hydrogenation process mainly comprises three technologies of fixed bed hydrogenation, fluidized bed hydrogenation and suspended bed hydrogenation. The fixed bed hydrogenation technology has the advantages of simple and mature process flow and equipment structure, simple and convenient device operation, high product yield, and mainly has the technical defects that the catalyst is easy to coke and poison, the operation period is short (generally 12 months), and the adaptability to poor raw materials is poor; the fluidized bed hydrogenation technology can realize the on-line supplement and discharge of the catalyst, can keep the higher activity of the catalyst in the reactor, can process high-sulfur, high-carbon residue and high-metal inferior heavy oil compared with the fixed bed hydrogenation technology, and has higher conversion rate, but the technology has the defects of large device investment, complex equipment structure, large catalyst loss, high operation cost and the like; the suspension bed hydrogenation technology is a research hotspot in the field of heavy oil processing in recent years, is suitable for processing inferior heavy oil with high metal content, high carbon residue, high sulfur content, high acid value and high viscosity, and has the advantages of high conversion rate, high light oil yield, relatively simple reactor structure, low device operation cost and the like.

The heavy oil decarbonization process mainly comprises delayed coking, visbreaking, solvent deasphalting, heavy oil catalytic cracking and the like. Currently, the heavy oil decarbonization process most used in the oil refining industry is still a delayed coking process technology. The delayed coking technology has the advantages of simple process, mature technology, low equipment investment and operation cost, strong adaptability of raw materials and the like, and plays a crucial role in the heavy oil processing technology, but the delayed coking also has the problems of high coke yield and the like.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

A first object of the present invention is to provide a heavy oil processing method which has a low coke formation rate and a significantly improved liquid yield as compared with the conventional delayed coking method.

A second object of the present invention is to provide a heavy oil processing system that has a small modification to existing heavy oil processing systems and reduces the difficulty of renewal.

In order to achieve the above purpose, the invention provides the following technical scheme:

a method of processing heavy oil comprising the steps of:

step A: enabling hydrogen-rich gas and a heavy oil raw material to react in a low-temperature cold plasma reactor to generate a first product; the weight ratio of the hydrogen-rich gas to the heavy oil raw material is 0.001-0.2: 1, preferably 0.005-0.15: 1;

and B: subjecting the first product to delayed coking to produce a second product;

and C: and fractionating the gas-liquid phase component in the second product to obtain products with different fractions.

The plasma is a fourth state material except for gas, liquid and solid three-state materials. The plasma is composed of several typical particles, i.e., electrons, positive ions, negative ions, excited state atoms or molecules, ground state atoms or molecules, and the like. Since the total number of negative charges is equal to the total number of positive charges, it is macroscopically electrically neutral and thus called plasma. The plasma contains a large number of ions, energetic electrons, excited atoms or molecules, etc., and can provide a large number of reactive groups which are prone to chemical reactions. Depending on the temperature, plasmas can be divided into two categories: high temperature plasmas (such as the sun, nuclear fusion plasmas, etc.) and low temperature plasmas. Low temperature plasmas can be further classified into thermal plasmas (such as those generated by arc discharge and combustion) and cold plasmas (such as those generated by glow discharge, corona discharge, dielectric barrier discharge, etc.). Plasma is considered as a new clean energy technology as a new molecular activation mode. With the development of plasma technology, the application of the plasma technology in the chemical field is more and more.

The invention is based on the unique activity of plasma, and the plasma is used for strengthening the traditional delayed coking reaction process to activate the raw oil, thereby improving the yield of the liquid oil.

In the invention, firstly, in the step A, hydrogen-rich gas generates plasma and is converted into excited state particles or free radicals, meanwhile, part of raw material heavy oil molecules are subjected to cracking reaction and are cracked into more than two short chain free radicals, the short chain free radicals are protected by using the plasma state of the hydrogen-rich gas, the recoupling of the short chain free radicals is avoided, and meanwhile, the excited state hydrogen-rich gas particles can also perform hydrogenation reaction with part of active state heavy oil molecules. Therefore, the low-temperature cold plasma reaction activates the heavy oil raw material, so that the reaction rate of subsequent delayed coking is improved, and the reaction energy consumption is reduced; on the other hand, partial hydrogenation reaction is generated, so that the reaction quantity of subsequent delayed coking is reduced, and the liquid yield is also improved.

And then, the delayed coking reaction is carried out in the step B, namely, the activated raw material heavy oil is heated by a heating furnace and rapidly heated to the coking reaction temperature, and enters a coke tower for coking reaction.

The final fractionation determines the fraction interval according to the product requirements, and common valuable products comprise gasoline, diesel oil, wax oil, heavy wax oil, gas and the like.

In the present invention, the weight ratio of the hydrogen-rich gas to the heavy oil feedstock is 0.001 to 0.2:1, for example, 0.001:1, 0.003:1, 0.005:1, 0.007:1, 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.17:1, 0.2:1, and preferably 0.005 to 0.15: 1.

Compared with the traditional delayed coking method, the processing method of the invention improves the liquid yield by at least 4 percent, and correspondingly reduces the coke rate by at least 5 percent.

The above processing method of the present invention can be further improved from the following points:

preferably, the reaction temperature in the low-temperature cold plasma reactor is 100-400 ℃, preferably 180-350 ℃;

the reaction temperature in the low-temperature cold plasma reactor is related to the activation degree and hydrogenation degree of the raw material heavy oil, and the liquid yield is higher when the reaction temperature is higher. The carbon chain may be lengthened when the reaction temperature is too high, which is not beneficial to heavy oil upgrading. The optimized reaction temperature is 100-400 deg.C, such as 100 deg.C, 120 deg.C, 140 deg.C, 150 deg.C, 200 deg.C, 250 deg.C, 300 deg.C, 330 deg.C, 350 deg.C, 370 deg.C, 400 deg.C, etc., preferably 180-350 deg.C.

Preferably, the reaction temperature of the delayed coking is 400 ℃ to 550 ℃, preferably 475 ℃ to 525 ℃.

The reaction temperature of delayed coking is related to the quality of the raw heavy oil and the plasma reaction in the previous step, and the reaction temperature is preferably 475 ℃, 480 ℃, 490 ℃, 500 ℃, 510 ℃, 520 ℃ or 525 ℃ and the like (please modify according to the scope of the claims) after screening to obtain higher liquid yield.

Preferably, after the reaction in the low-temperature cold plasma reactor and before the delayed coking reaction, further:

fractionating the first product into a light fraction and a heavy fraction; subjecting the heavy fraction to said delayed coking.

At the moment, the light oil produced after the plasma reaction is separated in advance, and only heavy components are subjected to delayed coking, so that the production efficiency can be improved.

Preferably, the light component gas is returned to the low-temperature cold plasma reactor for further reaction.

The light components contain a large amount of hydrogen-rich gas, and the hydrogen-rich gas is returned to the low-temperature cold plasma reactor, so that the hydrogen-rich gas can be recycled, the resource utilization rate is improved, the hydrogen-rich gas can also serve as the steam in the traditional delayed coking process, the fluid linear speed is improved, and the carbon deposition phenomenon is slowed down.

The present invention is not limited to the amount of gas returned in the light fraction, and for example, the ratio of the gas that can be returned to this fraction to the feedstock heavy oil may be smaller due to the loss, depending on the ratio of the feedstock oil to the hydrogen-rich gas at the time of the initial reaction.

Preferably, the hydrogen-rich gas is a mixture of one or more of hydrogen, methane, ethane and propane.

The hydrogen-rich gas does not introduce foreign impurities, and the product quality is reduced. The present invention is described above with reference to hydrogen-rich gas, but the practical application is not limited thereto.

Preferably, the heavy oil raw material is one or more of atmospheric residue, vacuum residue, catalytic slurry oil, heavy crude oil, heavy oil, deoiled asphalt and refinery masonry oil.

These heavy oil raw materials are conventional inferior raw materials, and the present invention is only exemplified above, and the practical application is not limited thereto.

Preferably, the method further comprises the following steps: and C, returning the gas distilled off in the step C to the low-temperature cold plasma reactor for continuous reaction.

And the part of gas can be recycled, so that the resource utilization rate is improved, the part of gas can also serve as the steam in the traditional delayed coking process, the linear velocity of the fluid is improved, and the carbon deposition phenomenon is slowed down.

The present invention is not limited to the amount of gas returned in the final fraction, and for example, the ratio of the gas that can be returned to this portion to the feedstock heavy oil may be smaller due to the loss, depending on the ratio of the feedstock oil to the hydrogen-rich gas at the initial reaction.

Preferably, before the step a, the method further comprises:

preheating the hydrogen-rich gas to 50-300 ℃, preferably 120-260 ℃;

preheating the heavy oil raw material to 100-400 ℃, preferably 180-350 ℃.

The contact efficiency of the hydrogen-rich gas and the heavy oil raw material is improved through preheating, and the activation rate and the activation effect are improved.

The system corresponding to the processing method of the invention has the following structure:

the device comprises a low-temperature cold plasma reactor, a delayed coking unit and a fractionating tower which are sequentially connected through pipelines;

the low-temperature cold plasma reactor is used for: enabling hydrogen-rich gas and a heavy oil raw material to react in a low-temperature cold plasma reactor to generate a first product; the weight ratio of the hydrogen-rich gas to the heavy oil raw material is 0.001-0.2: 1, preferably 0.005-0.15: 1;

the delayed coking unit is to: subjecting the first product to delayed coking to produce a second product;

the fractionation column is for: and fractionating the gas-liquid phase component in the second product to obtain products with different fractions.

The liquid yield of the system is improved by the raw materials as described above.

The delayed coking unit of the present invention includes a furnace unit and a coke drum unit.

Preferably, another fractionating tower is connected between the low-temperature cold plasma reactor and the delayed coking unit.

Two fractionating towers are arranged for twice fractionation, so that the reaction efficiency is improved.

Preferably, the fractionating tower and the other fractionating tower are provided with gas outlets, and the gas outlets of the fractionating tower and the other fractionating tower are connected with the low-temperature cold plasma reactor through pipelines.

The structure facilitates the gas in the fraction to flow back to the low-temperature cold plasma reactor to participate in the plasma reaction.

Preferably, the low-temperature cold plasma reactor is a dielectric barrier discharge reactor, such as a parallel plate type or coaxial type dielectric barrier discharge reactor. The type of reactor of the present invention is not limited thereto.

In summary, compared with the prior art, the invention achieves the following technical effects:

(1) the coke rate of the invention is low;

(2) the liquid yield of the invention is high;

(3) the invention does not need to inject steam, obviously reduces the discharge amount of process waste water and is more environment-friendly;

(4) the invention recycles gas, reduces raw material consumption and saves energy;

therefore, the process of the invention can replace the traditional delayed coking process and generate great economic value and social benefit.

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 description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Figure 1 is a schematic of heavy oil processing according to example 1 of the present invention.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

Heavy oil processing system and method

The system of this embodiment comprises: the low-temperature cold plasma reactor, the first fractionating tower, the delayed coking unit and the second fractionating tower are sequentially connected through pipelines.

The first fractionating tower and the second fractionating tower are provided with gas outlets, and the gas outlets of the first fractionating tower and the second fractionating tower are connected with the low-temperature cold plasma reactor through pipelines.

The low-temperature cold plasma reactor is a dielectric barrier discharge reactor.

The route for processing heavy oil by using the system is shown in figure 1:

preheating a gas raw material (hydrogen) to 150 ℃, entering the upper part of the low-temperature cold plasma reactor through a pipeline, and preheating the raw material oil to 280 ℃, entering the side surface of the upper part of the low-temperature cold plasma reactor through the pipeline; the method comprises the following steps of (1) reacting a gas raw material and raw oil in a low-temperature cold plasma reactor, wherein the low-temperature cold plasma reactor is a parallel plate type dielectric barrier discharge reactor, the temperature of the low-temperature cold plasma reactor is controlled at 280 ℃, the mass ratio of the gas raw material to the raw oil is 0.08, and the reacted material enters a fractionation system through a pipeline for separation; the separated heavy fraction enters a delayed coking unit through a pipeline, the separated light component enters a fractionating tower through a pipeline, or the gas in part of the light component is mixed with the heavy component through a pipeline and then enters the delayed coking unit, and the mass ratio of the gas in the light component entering the delayed coking unit through the pipeline to the raw oil is about 0.05; the reaction temperature of the delayed coking unit is 500 ℃, and the generated oil gas enters a fractionating tower through a pipeline; the oil gas generated by the delayed coking reaction is subjected to product separation in a fractionating tower to obtain products such as gas, gasoline, diesel oil, wax oil and heavy wax oil; part of gas products separated by the fractionating tower return to the low-temperature cold plasma reactor for reaction through a pipeline, and the mass ratio of the gas products (recycle gas products) returned by the pipeline to the raw oil is about 0.04.

The properties of the feed oil used in this example are shown in Table 1, and the comparison of the operating conditions and product distribution of this example with those of the conventional delayed coking process is shown in Table 2. As can be seen from Table 2, the process of the present invention increases the liquid product yield by 4.39 percentage points and the amount of coking water injection (steam) by 0, compared to the conventional delayed coking process.

TABLE 1 analysis of Properties of raw materials

TABLE 2 operating conditions and product distribution

Example 2

The same processing system and raw heavy oil as in example 1 were used, but the processing conditions differed:

the reaction temperature in the low-temperature cold plasma reactor of this example was 100 deg.C, the reaction temperature for delayed coking was 475 deg.C, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 62.51% (mass%).

Example 3

the reaction temperature in the low-temperature cold plasma reactor of this example was 400 deg.C, the reaction temperature for delayed coking was 515 deg.C, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 67.11% (mass%).

Example 4

the reaction temperature in the low-temperature cold plasma reactor of this example was 180 ℃, the reaction temperature for delayed coking was 500 ℃, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 65.23% (mass%).

Example 5

the initial hydrogen to feed heavy oil weight ratio in this example was 0.001:1, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 63.55% (mass%).

Example 6

the weight ratio of initial hydrogen to the raw heavy oil in this example was 0.2:1, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 66.46% (mass%).

Example 7

the initial hydrogen to feed heavy oil weight ratio in this example was 0.005:1, and the other reaction conditions were the same as in example 1.

This example finally gives a liquid product yield of 65.93% (mass%).

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of processing heavy oil, comprising the steps of:

step A: enabling hydrogen-rich gas and a heavy oil raw material to react in a low-temperature cold plasma reactor to generate a first product;

the weight ratio of the hydrogen-rich gas to the heavy oil raw material is 0.001-0.2: 1;

fractionating the first product into a light component and a heavy component, and returning the gas of the light component to the low-temperature cold plasma reactor for continuous reaction;

and B: subjecting the heavy fraction to delayed coking to produce a second product;

and C: fractionating the gas-liquid phase component in the second product to obtain products with different fractions;

the reaction temperature in the low-temperature cold plasma reactor is 180-300 ℃.

2. The heavy oil processing method according to claim 1, wherein the weight ratio of the hydrogen-rich gas to the heavy oil feedstock is 0.005 to 0.15: 1.

3. A heavy oil processing method according to claim 1, wherein the reaction temperature of the delayed coking is 400 ℃ to 550 ℃.

4. The heavy oil processing method of claim 1 wherein the reaction temperature of the delayed coking is 475 ℃ to 525 ℃.

5. The heavy oil processing method of claim 1 wherein the hydrogen-rich gas is a mixture of one or more of hydrogen, methane, ethane, and propane.

6. The heavy oil processing method according to claim 1, wherein the heavy oil feedstock is one or more of atmospheric residue, vacuum residue, catalytic slurry oil, heavy crude oil, heavy oil, deoiled asphalt, and refinery masonry oil.

7. The heavy oil processing method of claim 1, further comprising: and C, returning the gas distilled off in the step C to the low-temperature cold plasma reactor for continuous reaction.

8. A heavy oil processing method according to claim 1, further comprising, before said step a:

preheating the hydrogen-rich gas to 50-300 ℃;

preheating the heavy oil raw material to 100-400 ℃.

9. A heavy oil processing method according to claim 8, wherein the hydrogen-rich gas is preheated to 120 ℃ to 260 ℃.

10. A heavy oil processing method according to claim 8, wherein the heavy oil feedstock is preheated to 180 ℃ to 350 ℃.

11. A system for the heavy oil processing method of any one of claims 1 to 10, comprising a low-temperature cold plasma reactor, a delayed coking unit and a fractionating tower connected in series by a pipeline;

the low-temperature cold plasma reactor is used for: enabling hydrogen-rich gas and a heavy oil raw material to react in a low-temperature cold plasma reactor to generate a first product; the weight ratio of the hydrogen-rich gas to the heavy oil raw material is 0.001-0.2: 1;

the delayed coking unit is to: carrying out delayed coking on heavy components obtained after the first product is fractionated to generate a second product;

the fractionation column is for: fractionating the gas-liquid phase component in the second product to obtain products with different fractions;

and another fractionating tower is connected between the low-temperature cold plasma reactor and the delayed coking unit.

12. The system of claim 11, wherein the fractionating column and the further fractionating column are each provided with a gas outlet, and the gas outlets of both are connected to the cold plasma reactor via a pipeline.

13. The system of claim 11, wherein the low temperature cold plasma reactor is a dielectric barrier discharge reactor.