CN108998060B

CN108998060B - Novel process for producing low-sulfur coke

Info

Publication number: CN108998060B
Application number: CN201810969443.XA
Authority: CN
Inventors: 蒋兴家; 王龙延; 崔新安; 申明周; 唐应彪; 李春贤
Original assignee: Sinopec Engineering Group Co Ltd; Sinopec Luoyang Technology Co Ltd
Current assignee: Sinopec Engineering Group Co Ltd; Sinopec Luoyang Technology Co Ltd
Priority date: 2018-08-23
Filing date: 2018-08-23
Publication date: 2021-06-08
Anticipated expiration: 2038-08-23
Also published as: CN108998060A

Abstract

The invention discloses a novel process for producing low-sulfur coke, which comprises the following steps: mixing residual oil with oxidant, microwave pre-treating and coking to obtain low sulfur coke. The invention provides a novel process for preparing low-sulfur petroleum coke by a residual oil microwave pretreatment oxidation one-step method from raw materials for preparing the petroleum coke and by combining the characteristics of chemical oxidation and selective heating of microwave pretreatment.

Description

Novel process for producing low-sulfur coke

Technical Field

The invention relates to the technical field of low-sulfur petroleum coke preparation, and in particular relates to a novel process for producing low-sulfur coke.

Background

In recent years, the demand of high-quality low-sulfur petroleum coke (the sulfur content is lower than 3%) is increasing in China. However, petroleum coke products in China generally have the problem of high sulfur content (the sulfur content is higher than 3%). The higher sulfur content in petroleum coke not only limits the utilization way of the petroleum coke, but also reduces the utilization value of the petroleum coke. The use of high sulfur petroleum coke also causes problems, such as the generation of a large amount of sulfur-containing gas (such as sulfur dioxide), which causes environmental pollution; can cause corrosion of equipment and increase the production cost of enterprises. Therefore, how to obtain low-sulfur petroleum coke is a problem which needs to be solved urgently by related enterprises.

At present, the subsequent desulfurization treatment is mainly carried out on the existing high-sulfur petroleum coke to obtain low-sulfur petroleum coke. Common desulfurization methods include high temperature calcination, wet chemical oxidation, medium gas desulfurization, solvent extraction, and the like. The high-temperature calcination method needs calcination at more than 1600 ℃ to ensure that the desulfurization rate exceeds 50 percent, and the energy consumption is large; the wet chemical oxidation method converts organic sulfur which is insoluble in water in petroleum coke into inorganic sulfur which is soluble in water or acid through the oxidation of chemical agents so as to achieve the aim of desulfurization, but the method generates a large amount of waste water. The medium gas desulfurization refers to that the petroleum coke is placed in a desulfurization medium gas for a period of constant temperature, so that sulfur in the petroleum coke and the medium gas interact to achieve the aim of desulfurization, but the method has high energy consumption and great danger. The solvent extraction method is a method for removing sulfur in petroleum coke by using a solvent extraction method, and although the method is simpler, the desulfurization rate is low, and most of organic solvents are toxic, flammable and explosive, and have higher cost. Therefore, the development of a new process for producing low-sulfur coke has very important practical significance.

Disclosure of Invention

The invention aims to provide a novel process for producing low-sulfur coke, which overcomes the defect of sulfur removal of various high-sulfur petroleum cokes and has the advantages of higher efficiency, more energy conservation, higher safety and environmental protection.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

The invention provides a novel process for producing low-sulfur coke, which is characterized in that residual oil and an oxidant are mixed, and the low-sulfur coke is prepared through microwave pretreatment and coking treatment.

The invention has the beneficial effects that:

the invention provides a novel process for producing low-sulfur coke, which can realize the production of the low-sulfur coke in one step, has the advantages of low investment, quick response, no pollution and clean production.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a flow chart of the production of low sulfur coke in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

Because the petroleum coke has a compact structure, once the sulfur content of the petroleum coke is high, the desulfurization treatment is carried out, the difficulty is high, and the cost is high. The sulfur content of petroleum coke mainly depends on the sulfur content and sulfur form in the raw material for producing petroleum coke, namely, residual oil, if the residual oil is pretreated before entering a coking tower, the sulfur form in the residual oil is changed, so that the residual oil is converted into sulfur-containing gas in the coking process, and the low-sulfur petroleum coke can be obtained. Therefore, the development of a new process for producing low-sulfur coke has very important practical significance.

The invention provides a novel process for preparing low-sulfur petroleum coke by a one-step method of residual oil microwave pretreatment oxidation, which starts from raw materials for preparing petroleum coke and combines the selective heating characteristics of chemical oxidation and microwave pretreatment.

The novel process for producing low sulfur coke provided by the examples of the present invention is described in detail below.

The embodiment of the invention provides a novel process for producing low-sulfur coke, which is used for preparing the low-sulfur coke by mixing residual oil and an oxidant and carrying out microwave pretreatment and coking treatment.

Referring to the preparation process in fig. 1, in the present invention, an oxidant and residual oil are mixed and added into a microwave treatment tank for microwave pretreatment, and sulfur-containing compounds in the residual oil mainly comprise mercaptan (RSH), thioether (RSR), disulfide (RSSR), thiophene, etc. The sulfur-containing compound with high polarity contained in the residual oil can easily absorb microwaves, the sulfur-containing compound reacts with an oxidant under the strong vibration action of the microwaves to generate sulfur-containing components (such as sulfone substances) which are easily removed in the coking process, the microwave pretreatment changes the form of sulfur in the residual oil, so that the sulfur-containing components are separated from the residual oil, the residual oil after the microwave pretreatment is directly transferred into a coking tower for coking treatment, the coking treatment converts the sulfur-containing components (such as the sulfone substances) of the residual oil into sulfur-containing gas, the sulfur-containing gas is introduced into a tail gas treatment system, the generated crude oil is introduced into a fractionation system, the generated coke is low-sulfur coke, and the coke is introduced into a coke system after being decoked.

The preparation method provided by the embodiment of the invention has the advantages that the preparation process is simple and high in efficiency, the oxidant and the residual oil are mixed, the microwave pretreatment is carried out, so that the sulfur-containing compound in the residual oil is separated from the residual oil, the residual oil after the microwave pretreatment is directly transferred into a coking tower for coking treatment without separation and purification operations, the yield of the obtained low-sulfur coke is high, the sulfur content is low, and the preparation method is a novel green and environment-friendly process.

In some embodiments, the oxidizing agent is selected from at least one of persulfates, sulfates, peroxides, mixed solvents of peroxides and acetic acid, potassium dichromate, potassium permanganate, chlorates, hypochlorites, oleum, nitric acid, preferably peroxides and nitric acid, preferably the peroxides are dibenzoyl peroxide, dicumyl peroxide, and mixed solvents of hydrogen peroxide and acetic acid.

In some embodiments, the mass ratio of oxidant to residual oil is between 0.5% and 10%, preferably between 0.5% and 5%, more preferably between 1% and 3%.

The above oxidant in the invention is easy to react with sulfur-containing components in the residual oil, namely mercaptan (RSH), thioether (RSR), disulfide (RSSR), thiophene and the like, so as to change the form of sulfur in the residual oil (such as generation of sulfone substances), the amount of the added oxidant can be selected according to the addition amount of the residual oil, and the ratio of the oxidant to the residual oil in the invention can ensure that the sulfur-containing components in the residual oil are fully reacted and separated.

In some embodiments, the microwave pretreatment is performed in a microwave pretreatment tank. The microwave pretreatment frequency is 300-3000 MHz, preferably 900-2500MHz, more preferably 915MHz and 2450MHz, the treatment temperature of the microwave pretreatment is 50-450 ℃, preferably 100-250 ℃, and the treatment time of the microwave pretreatment is 0.5-4h, preferably 0.5-2h, more preferably 0.5-1.5 h.

Microwave refers to electromagnetic wave with frequency of 300 MHz-300 GHz, and is short for a limited frequency band in radio wave. One notable feature of microwaves is: the heating property is selected, namely the intensity of microwave absorption of a substance is substantially related to the complex dielectric constant of the substance, namely the larger the loss factor is, the stronger the microwave absorption capacity is, and the substance with polar molecules can absorb the microwave, and belongs to the substance with large loss factor, such as: water, acid, and the like. Their molecules have a permanent dipole moment, i.e. the centers of the positive and negative charges of the molecules do not coincide. The polar molecules change orientation rapidly along with the frequency of the microwave in the microwave field, and rotate back and forth, so that the molecules collide and rub with each other, and the energy of the microwave is absorbed to increase the temperature. The sulfur-containing component in the residual oil has higher polarity, is easy to absorb microwaves, and can quickly react with the oxidant under the action of the microwaves to change the form of the sulfur-containing component, such as the generation of sulfone substances, so that the sulfur-containing component is separated from the residual oil.

Experiments show that the removal of sulfur-containing components in residual oil can be accelerated by increasing the frequency of microwave treatment, the microwave pretreatment frequency in the embodiment of the invention is 300-3000 MHz, preferably 900-2500MHz, and further preferably 915MHz and 2450MHz, the sulfur-containing components in the residual oil can be rapidly and effectively removed by the microwave treatment frequency above, the further increase of the microwave power can form cavitation shielding in oxidation liquid, and the efficiency is reduced.

Above microwave preliminary treatment temperature and time can effectively get rid of the sulphur component in the residual oil, and when the processing temperature was crossed low or the time was short excessively, can't make oxidant and the sufficient oxidation that takes place of sulphur component, cause the sulphur removal inefficiency, when processing temperature was crossed high or time was too long, can not bring the further promotion of desulfurization efficiency.

In some embodiments, the coking process is carried out in a coke drum having a temperature of 450 to 550 ℃, preferably 450 to 500 ℃, and more preferably 490 ℃.

In some embodiments, the coking treatment time is 0.5 to 8 hours, preferably 0.5 to 4 hours, and more preferably 1 to 2 hours.

In some embodiments, the sulfur-containing gas produced by the coking process is introduced into a tail gas treatment system and the crude oil produced is introduced into a fractionation system, the coke produced is a low sulfur coke, and the coke is decoked and then enters a coke system.

Petroleum coking is one of petroleum refining processes, and is a process of converting residual oil into gas, gasoline, diesel oil, heavy distillate oil and petroleum coke through deep cracking reaction under the conditions of heating and long reaction time. Through the coking treatment, the residual oil can be converted into the required low-sulfur coke, meanwhile, sulfur-containing substances (such as sulfone substances) in the residual oil are converted into sulfur-containing gas, the sulfur-containing gas is directly treated, and the crude oil enters a fractionation system.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

Mixing residual oil with an oxidant (the oxidant/the residual oil (0 percent) is selected from a mixture of hydrogen peroxide and acetic acid), adding the mixture into a microwave pretreatment tank, wherein the microwave pretreatment temperature is 150 ℃, the frequency is 915MHz, and the time is 1h, then carrying out coking treatment, the temperature of a coking tower is 490 ℃, and the coking treatment time is 2h, thus preparing the low-sulfur coke, wherein the sulfur content of the low-sulfur coke is 3.43 percent.

Examples 2-23, the experimental procedure was similar to example 1, except for the differences in the parameters.

Comparative examples 24-26, the experimental procedure is similar to example 1, except for the differences in the parameters.

In comparative examples 27 to 32, the residue was not subjected to microwave pretreatment and was directly subjected to coking treatment to obtain coke.

The test parameters and coke sulfur content in examples 1-29 are shown in Table 1:

^amolar ratio of 1:1

As can be seen from table 1, the sulfur content of the microwave pretreated residual oil is much lower than that of the microwave pretreated residual oil compared with that of the microwave pretreated residual oil without the microwave pretreatment; in the microwave pretreatment implementation range of the embodiment of the invention, the higher the microwave pretreatment frequency is, the higher the temperature is, the longer the time is, the more beneficial to the removal of sulfur-containing components in residual oil is, so that the sulfur content in the obtained low-sulfur coke is lower, and the sulfur content exceeds the microwave pretreatment implementation range of the embodiment of the invention, even if the microwave pretreatment time is further prolonged, the temperature and the frequency of the microwave pretreatment are improved, and the desulfurization efficiency is not obviously improved; the longer the coking process, the more sulfur-containing coke is produced.

In summary, the novel process for producing low-sulfur coke provided by the present invention comprises the steps of mixing the residual oil with the oxidant, performing microwave pretreatment, wherein the sulfur-containing compound in the residual oil is easy to absorb microwaves, and reacting the sulfur-containing compound with the oxidant under the microwave pretreatment, so as to change the form of sulfur in the residual oil (such as generation of sulfone substances), separate the sulfur-containing compound from the residual oil, and reduce the sulfur content in the raw material residual oil, therefore, after the microwave pretreatment, the residual oil overcomes the defects of complex process and low efficiency in the existing preparation of low-sulfur coke by reducing the sulfur content in the coke after the preparation, and on the other hand, after the microwave pretreatment, the separation and purification treatment are not required, the residual oil after the microwave pretreatment is directly introduced into a coking tower for coking treatment, and the separation and purification treatment process is omitted, the microwave pretreated residual oil is used as a raw material for coking treatment, then coking and coking treatment are carried out, the coking treatment enables sulfur-containing substances to be converted into sulfur-containing gas, the sulfur-containing gas enters a tail gas treatment system, the generated crude oil enters a fractionation system, the generated coke is low-sulfur coke, and the coke is decoked and then enters a coke system. The coking process is simple and efficient, and the generated substances are respectively treated correspondingly.

Compared with the prior coke desulfurization technology, the process has the following advantages:

1. the process is used for pretreating the coke making raw materials, and can realize the control and centralized recovery treatment of sulfur from the source.

2. The process adopts microwave pretreatment technology, utilizes the characteristics of selective heating of microwave and the like, can selectively oxidize the sulfur-containing polar components in the residual oil, changes the sulfur form in the residual oil, converts the sulfur form into an easily removable form, and has high treatment efficiency.

3. The process adopts a microwave pretreatment technology, the microwave pretreatment temperature is low, the reaction is fast, the operation is simple and convenient, and the automatic control is easy to realize.

4. The process can realize the production of low-sulfur coke in one step, has the advantages of low investment, quick response, no pollution and clean production.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the 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.

Claims

1. A low-sulfur coke production process is characterized in that residual oil and an oxidant are mixed, and a low-sulfur coke is prepared through microwave pretreatment and coking treatment;

wherein the microwave pretreatment is carried out in a microwave pretreatment tank, the treatment frequency of the microwave pretreatment is 900-2500MHz,

the treatment temperature of the microwave pretreatment is 100-250 ℃,

the treatment time of the microwave pretreatment is 0.5-2h,

the coking treatment is carried out in a coke tower, the treatment temperature of the coking treatment is 450-550 ℃, the treatment time of the coking treatment is 0.5-8h,

introducing sulfur-containing gas generated by the coking treatment into a tail gas treatment system, introducing the generated crude oil into a fractionation system, wherein the generated coke is low-sulfur coke, and entering a coke system after decoking.

2. The process for producing low sulfur coke according to claim 1, wherein the oxidizing agent is at least one selected from the group consisting of persulfates, sulfates, peroxides, mixed solvents of peroxides and acetic acid, potassium dichromate, potassium permanganate, chlorates, hypochlorites, oleum, and nitric acid.

3. The low sulfur coke production process of claim 2, wherein the oxidizing agent is selected from the group consisting of peroxides selected from at least one of dibenzoyl peroxide, dicumyl peroxide, and a mixed solvent of hydrogen peroxide and acetic acid, and nitric acid.

4. The low sulfur coke production process of claim 1, wherein the mass ratio of oxidant to resid is 0.5% to 10%.

5. The low sulfur coke production process of claim 1 wherein the coking process has a processing temperature of 450-500 ℃.

6. The low sulfur coke production process of claim 1, wherein the coking process has a treatment time of 0.5 to 4 hours.