阅读说明：本技术 一种由高金属含量原料油制备石油焦的装置及方法 (Device and method for preparing petroleum coke from high-metal-content raw oil ) 是由 蔡烈奎 王志超 裴晓光 王伟 王衍法 于 2020-04-16 设计创作，主要内容包括：本发明提供了一种由高金属含量原料油制备石油焦的装置及方法,所述装置包括一级焦化单元、二级焦化单元和分馏单元,所述一级焦化单元的顶部出口经分馏单元的底部与二级焦化单元的入口相连,所述二级焦化单元的顶部出口与分馏单元的入口相连；每级焦化单元均包括预热装置和焦炭塔,所述预热装置的出口与焦炭塔的入口相连。本发明以高金属含量原料油为原料,通过两级焦化单元的设置,根据原料油中金属组分的存在形式,利用其化学特性进行分解脱除,从而制备得到满足技术要求的优质石油焦；所述装置结构简单,设备成本低,所述方法操作简便,对原料的适应性好,扩展了生产企业的操作弹性,提升了经济效益,适合大规模应用。(The invention provides a device and a method for preparing petroleum coke from high-metal-content raw oil, wherein the device comprises a primary coking unit, a secondary coking unit and a fractionation unit, wherein a top outlet of the primary coking unit is connected with an inlet of the secondary coking unit through the bottom of the fractionation unit, and a top outlet of the secondary coking unit is connected with an inlet of the fractionation unit; each stage of coking unit comprises a preheating device and a coke drum, wherein the outlet of the preheating device is connected with the inlet of the coke drum. According to the invention, raw oil with high metal content is used as a raw material, and decomposition and removal are carried out by utilizing the chemical characteristics of the raw oil according to the existence form of metal components in the raw oil through the arrangement of two stages of coking units, so that high-quality petroleum coke meeting the technical requirements is prepared; the device has the advantages of simple structure, low equipment cost, simple and convenient operation of the method, good adaptability to raw materials, expanded operation flexibility of production enterprises, improved economic benefit and suitability for large-scale application.)

1. The device for preparing the petroleum coke from the high-metal-content raw oil is characterized by comprising a primary coking unit, a secondary coking unit and a fractionation unit, wherein a top outlet of the primary coking unit is connected with an inlet of the secondary coking unit through the bottom of the fractionation unit, and a top outlet of the secondary coking unit is connected with an inlet of the fractionation unit; each stage of coking unit comprises a preheating device and a coke drum, wherein the outlet of the preheating device is connected with the inlet of the coke drum.

2. The apparatus of claim 1, wherein the preheating means comprises a furnace;

preferably, the furnace comprises a convection section and a radiant section.

3. The apparatus of claim 1 or 2, wherein the primary coking unit comprises a first preheater and a first coke drum, the secondary coking unit comprises a second preheater and a second coke drum, and the top outlet of the first coke drum is connected to the inlet of the second preheater via the bottom of the fractionation unit;

preferably, the fractionation unit comprises a fractionation column.

4. A method for producing petroleum coke using the apparatus of any one of claims 1-3, wherein the method comprises the steps of:

(1) preheating the high-metal content raw oil, and then carrying out mild thermal cracking to obtain coke and first-stage coking oil gas;

(2) the first-stage coking oil gas obtained in the step (1) is heated again after heat and mass transfer at the bottom of the fractionation unit for cracking and coke formation reaction to obtain petroleum coke and second-stage coking oil gas;

(3) and (3) fractionating the secondary coking oil gas obtained in the step (2) to obtain gas, light oil and heavy oil, and returning part of the heavy oil to the step (2) for reaction.

5. The method according to claim 4, wherein the high metal content raw oil of step (1) comprises any one of or a combination of at least two of atmospheric residue, vacuum residue, ethylene tar, furfural extract oil or fuel oil;

preferably, the metal content in the high-metal-content raw oil is 200-1000 ppm;

preferably, the metal components in the raw oil comprise vanadium, iron, calcium, nickel and sodium;

preferably, the raw oil takes steam as a conveying gas.

6. The method according to claim 4 or 5, wherein said preheating of step (1) is performed in a first preheating device;

preferably, the temperature of the preheated raw oil in the step (1) is 420-480 ℃;

preferably, said mild thermal cracking of step (1) is conducted in a first coke drum;

preferably, the reaction pressure in the first coke tower is 0.1-0.2 MPa;

preferably, the residence time in the first coke tower is 0.1-12 h;

preferably, water or steam is injected into the raw oil during preheating in the step (1), and the injection amount accounts for 0-20 wt% of the mass of the raw oil.

7. The process of any of claims 4-6, wherein after said mild thermal cracking of step (1), the metal components in the feedstock oil are enriched in the coke product;

preferably, the content of each metal in the first-stage coking oil gas in the step (1) is not more than 50 ppm;

preferably, the yield of the coke in the step (1) is 1-5%.

8. The method of any one of claims 4-7, wherein the first stage coker gas oil of step (2) is mixed with the bottom fraction of the fractionation unit and is heated by a second preheating device;

preferably, the temperature of the mixed raw materials after being heated by the second preheating device is 490-520 ℃;

preferably, the cracking and coking reaction of step (2) is carried out in a second coke drum;

preferably, the reaction pressure in the second coke tower is 0.1-0.2 MPa;

preferably, the residence time in the second coke tower is 16-24 h;

preferably, water or steam is injected into the feeding material when the heating in the step (2) is carried out again, wherein the injection amount accounts for 0-20 wt% of the feeding amount;

preferably, the circulation ratio of the second coke drum is 0.1-1.0;

preferably, the petroleum coke of step (2) is agglomerated in a second coke drum.

9. The process of any of claims 4-8, wherein said fractionating of step (3) is performed in a fractionation column;

preferably, the light oil of step (3) comprises gasoline and diesel;

preferably, the heavy oil in step (3) comprises wax oil and bottom cycle oil.

10. A petroleum coke produced by the process of any one of claims 4 to 9.

Technical Field

The invention belongs to the technical field of petroleum coking, and relates to a device and a method for preparing petroleum coke from high-metal-content raw oil.

Background

Petroleum coke, as a petroleum product, including ordinary petroleum coke, acicular petroleum coke and the like, is a main raw material of an ordinary power graphite electrode for steelmaking or a prebaked anode for electrolytic aluminum, however, at present, few enterprises capable of producing petroleum coke are available, so that the cost is high, and the application of the petroleum coke in the steelmaking and electrolytic aluminum industries is limited.

At present, the main factor influencing the quality of petroleum coke is the high metal content in the raw materials of a delayed coking device, so that the metal content in the petroleum coke produced by the process cannot meet the technical requirements of high-quality petroleum coke, and the production process of the petroleum coke needs to be improved. CN 102634361A discloses a preparation method of needle petroleum coke, which comprises the steps of putting petroleum paraffin base or naphthenic base heavy raw materials into a test tube, then placing the test tube into a tubular reaction kettle, pressurizing and sealing inert gas, preheating the reaction kettle, then heating to the carbonization temperature of 430-480 ℃, discharging gas to the initial pressure at intervals, measuring the volume of the discharged gas, and carbonizing for 12-18 h at the temperature after the gas volume is less than 10-20 ml/10min to obtain needle coke with complete coke blocks; however, the raw material used in the method does not relate to the treatment of metal components, the metal content of the raw material oil used in the method is high, the quality of petroleum coke obtained is greatly influenced, the steps of the method are numerous, the operating conditions need to be finely controlled, and the method is not suitable for large-scale production and application.

CN 1315490a discloses a method for producing acicular petroleum coke from atmospheric residue, which comprises subjecting atmospheric residue and cycle oil generated in the coking process to mild heat treatment, separating the generated light fraction from coking oil gas, heating the rest heavy fraction, introducing into a coke tower, leaving the generated coke in the coke tower, and separating the coking oil gas in a fractionating tower. CN 1325938A discloses a method for producing acicular petroleum coke from sulfur-containing atmospheric residue, which comprises the steps of sequentially carrying out hydrofining, hydrodemetallization and hydrodesulfurization on the sulfur-containing atmospheric residue, separating and hydrogenating to generate oil, obtaining hydrogenated heavy distillate oil, entering the hydrogenated heavy distillate oil into a delayed coking device, and then generating the acicular coke in a coke tower. In the above patent, the former also does not mention whether the raw oil contains metal and how to treat the raw oil, and the pretreatment hydrogenation operation in the latter not only increases the equipment and operation cost, but also makes the light fraction more active and increases the difficulty of subsequent processing.

For the treatment of raw oil with high metal content, at present, two processes are mainly used, namely, electric desalting operation, but the metal removal effect is poor based on the existence form of metal in the oil, and secondary problems such as corrosion and the like are brought to a production device; and secondly, a residual oil hydrogenation process is added before the delayed coking process to remove metal impurities in the raw materials, but the processing cost is increased sharply and the subsequent treatment difficulty is increased, so that a new method is required to be searched for the treatment of the raw oil with high metal content to reduce the difficulty of removing metal components so as to obtain high-quality petroleum coke.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a device and a method for preparing petroleum coke from high-metal-content raw oil, wherein the device is provided with a two-stage coking unit, and the metal component in the raw oil is removed by utilizing the characteristic of the metal component, so that a high-quality petroleum coke product is prepared; the device has the advantages of simple structure, simple and convenient operation method, low equipment and operation cost and suitability for large-scale application.

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

in one aspect, the invention provides a device for preparing petroleum coke from high-metal-content raw oil, which comprises a primary coking unit, a secondary coking unit and a fractionation unit, wherein a top outlet of the primary coking unit is connected with an inlet of the secondary coking unit through the bottom of the fractionation unit, and a top outlet of the secondary coking unit is connected with an inlet of the fractionation unit; each stage of coking unit comprises a preheating device and a coke drum, wherein the outlet of the preheating device is connected with the inlet of the coke drum.

According to the invention, the device takes high-metal-content raw oil as a raw material, through the arrangement of two-stage coking units, metal components in the raw oil are firstly removed, and the raw oil is decomposed and removed by utilizing the chemical characteristics according to the existence form of the metal components in the raw oil, so that the raw oil is prevented from entering petroleum coke products, and thus high-quality petroleum coke with low metal content is prepared and obtained, and the technical requirement of the petroleum coke is met; the oil gas component of the coking unit is fractionated to obtain a plurality of distillate oil, so that the utilization value of the raw material residual oil is greatly improved; the device has simple structure, does not need to add additional devices, has lower equipment cost and reduces the production cost of petroleum coke products.

The following technical solutions are preferred technical solutions of the present invention, but not limited to the technical solutions provided by the present invention, and technical objects and advantageous effects of the present invention can be better achieved and achieved by the following technical solutions.

As a preferable technical scheme of the invention, the preheating device comprises a heating furnace.

Preferably, the furnace comprises a convection section and a radiant section.

As a preferred technical scheme of the invention, the primary coking unit comprises a first preheating device and a first coke tower, the secondary coking unit comprises a second preheating device and a second coke tower, and the top outlet of the first coke tower is connected with the inlet of the second preheating device through the bottom of the fractionation unit.

According to the invention, the coking oil gas of the primary coking unit passes through the bottom of the fractionation unit, so that the primary separation of oil gas components can be realized, the raw material amount entering the secondary coking unit is reduced, the temperature can be raised by using the heat at the bottom of the fractionation unit, and simultaneously the heavy oil at the bottom is taken out and mixed to carry out the coking reaction again.

Preferably, the fractionation unit comprises a fractionation column.

In another aspect, the present invention provides a method for preparing petroleum coke from high metal content raw oil, wherein the method is performed by using the above apparatus, and comprises the following steps:

(1) preheating the high-metal content raw oil, and then carrying out mild thermal cracking to obtain coke and first-stage coking oil gas;

(2) the first-stage coking oil gas obtained in the step (1) is heated again after heat and mass transfer at the bottom of the fractionation unit for cracking and coke formation reaction to obtain petroleum coke and second-stage coking oil gas;

(3) and (3) fractionating the secondary coking oil gas obtained in the step (2) to obtain gas, light oil and heavy oil, and returning part of the heavy oil to the step (2) for reaction.

As a preferred technical scheme of the invention, the high metal content raw oil in the step (1) comprises any one or a combination of at least two of atmospheric residue, vacuum residue, ethylene tar, furfural extract oil or fuel oil, and typical but non-limiting examples of the combination include: the combination of the atmospheric residue oil and the vacuum residue oil, the combination of the vacuum residue oil and the ethylene tar, the combination of the atmospheric residue oil, the furfural extract oil and the fuel oil, the combination of the atmospheric residue oil, the vacuum residue oil, the ethylene tar and the furfural extract oil, and the like.

In the invention, the raw oil is mainly selected from raw materials capable of preparing low-sulfur petroleum coke, and various residual oils obtained in the petroleum refining process can be selected in the range, so that waste is changed into valuable, and the full utilization of residual oil components is realized.

Preferably, the metal content in the feed oil is 200 to 1000ppm, for example 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm or 1000ppm, but not limited to the recited values, and other values not recited in the above range are also applicable.

Preferably, the metal components in the feedstock oil include vanadium, iron, calcium, nickel and sodium.

In the invention, the metal content in the raw oil reaches the value, and if the raw oil is not removed first, the quality of petroleum coke products is greatly influenced; meanwhile, due to the composition characteristics of the raw oil, the metal component mainly exists in the form of organic metal salt compounds, such as naphthenate, fatty acid salt, phenolate and the like, so that the metal removal is carried out in a mode suitable for removing the organic metal salt.

Preferably, the raw oil takes steam as a conveying gas.

In the invention, because the raw oil is generally in a liquid state and is viscous and not easy to flow quickly in a pipeline, the gas is adopted as the conveying gas to be conveyed under the driving action of the conveying gas, and the steam is convenient to recover and low in energy consumption, and can also be used as the steam injection of a device and a pipeline simultaneously to avoid the influence on material conveying caused by coke formation in the pipeline.

As the preferable technical scheme of the invention, the preheating in the step (1) is carried out in a first preheating device, and the heating furnace selected by the invention comprises a convection section and a radiation section, namely, the raw oil sequentially flows through the convection section and the radiation section to be heated.

Preferably, the preheated raw oil in step (1) has a temperature of 420 to 480 ℃, for example, 420 ℃, 430 ℃, 440 ℃, 450 ℃, 460 ℃, 470 ℃ or 480 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, said mild thermal cracking of step (1) is conducted in a first coke drum.

Preferably, the reaction pressure in the first coke drum is 0.1 to 0.2MPa, for example, 0.1MPa, 0.12MPa, 0.14MPa, 0.16MPa, 0.18MPa or 0.2MPa, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

Preferably, the residence time in the first coke drum is 0.1 to 12 hours, such as 0.1 hour, 0.5 hour, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, or 12 hours, but is not limited to the recited values, and other values not recited in this range are equally applicable.

In the invention, proper reaction temperature and pressure are selected according to the composition and the property of the raw oil, and then the reaction residence time is determined.

Preferably, water or steam is injected into the raw oil during the preheating in step (1), and the injection amount is 0 to 20 wt% of the mass of the raw oil, for example, 0, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 13 wt%, 16 wt%, or 20 wt%, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.

According to the reaction parameters, the device and the pipeline can be injected with water or steam to reduce coke formation in the pipeline and the furnace tube and avoid influencing normal operation.

As a preferred technical scheme of the invention, after the mild thermal cracking in the step (1), the metal components in the raw oil are enriched in the coke product.

Preferably, the content of each metal in the first-stage coker oil gas in step (1) is not more than 50ppm, such as 50ppm, 45ppm, 40ppm, 35ppm, 30ppm, 25ppm, 20ppm, 15ppm or 10ppm, but is not limited to the recited values, and other unrecited values in the range of values are also applicable.

Preferably, the coke yield of step (1) is 1% to 5%, such as 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, or 1%, but not limited to the recited values, and other values not recited within the range are equally applicable.

According to the invention, through mild thermal cracking in the primary coke tower, the chemical characteristics of metal impurities such as naphthenate and metal porphyrin compounds are utilized, the metal impurities are decomposed in a heat treatment mode, most of the impurities are decomposed into a form of sulfide or oxide, the existing form is more stable, and the impurities are enriched in the byproduct coke under the process condition; therefore, the yield of the coke also influences the production of subsequent products, and if the yield of the coke is too high, the yield of the first-stage coking oil gas is reduced, and further the yield of high-quality petroleum coke is reduced, so that resource waste is caused, and economic benefits are influenced; if the coke yield is too low, the metal components are not completely removed and cannot be sufficiently introduced into the coke.

As a preferable technical scheme of the invention, the first-stage coking oil gas in the step (2) is mixed with the bottom fraction of the fractionation unit and enters a second preheating device together for heating.

In the invention, the primary coking oil gas passes through the bottom of the fractionation unit, so that the primary separation of oil gas components can be realized, the raw material amount entering a secondary coke tower is reduced, the temperature can be raised by utilizing the heat at the bottom of the fractionation unit, and simultaneously, the heavy oil at the bottom of the fractionation unit is taken out and mixed to perform cracking and coking reaction again.

Preferably, the temperature of the mixed raw material after heating by the second preheating device is 490 to 520 ℃, for example, 490 ℃, 495 ℃, 500 ℃, 505 ℃, 510 ℃, 515 ℃ or 520 ℃, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the cracking and coking reaction of step (2) is carried out in a second coke drum.

Preferably, the reaction pressure in the second coke drum is 0.1 to 0.2MPa, for example, 0.1MPa, 0.12MPa, 0.14MPa, 0.16MPa, 0.18MPa or 0.2MPa, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

According to the method, the proper reaction temperature is selected according to the composition and the property of the first-stage coking oil gas, the coking of a furnace tube is avoided, the pressure is adjusted according to the index requirement of the petroleum coke in the second-stage coke tower, so that the indexes of volatile matters and the like of the petroleum coke meet the standard requirement, and the yield of high-quality petroleum coke is adjusted.

Preferably, the residence time in the second coke drum is 16 to 24 hours, such as 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, or 24 hours, but not limited to the recited values, and other values not recited in this range are equally applicable.

Preferably, water or steam is injected into the feed during the reheating in step (2), and the injected amount is 0 to 20 wt% of the feed, such as 0, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 13 wt%, 16 wt% or 20 wt%, but not limited to the recited values, and other unrecited values in the range of values are also applicable.

Preferably, the recycle ratio of the second coke drum is 0.1 to 1.0, such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, or 1.0, but not limited to the recited values, and other values not recited within this range are equally applicable.

In the invention, the material entering the second preheating device comprises two parts, wherein one part is first-stage coking oil gas, namely the material entering the bottom of the fractionation unit, the other part is bottom fraction returning of the fractionation unit, the circulation ratio is the ratio of the latter to the former, and the retention time and the circulation ratio are adjusted according to the properties of raw materials and related process parameters to obtain high-quality petroleum coke meeting the requirements; the mode of water injection or steam injection is adopted to reduce the coke formation in the pipeline and the furnace tube so as to avoid influencing the normal operation.

Preferably, the petroleum coke of step (2) is agglomerated in a second coke drum.

As a preferred embodiment of the present invention, the fractionation in the step (3) is carried out in a fractionating column.

Preferably, the light oil of step (3) comprises gasoline and diesel.

Preferably, the heavy oil in step (3) comprises wax oil and bottom cycle oil.

According to the invention, raw oil can also obtain mixed oil-gas components besides petroleum coke, different fractions are obtained by separating different positions of a fractionating tower through the fractionation operation by utilizing different boiling points of the raw oil, and the raw oil is sequentially gas, gasoline, diesel oil, wax oil and bottom circulating oil from top to bottom, wherein the bottom circulating oil mainly comprises heavy wax oil.

On the other hand, the invention also provides the petroleum coke prepared by the method, and the performance of the petroleum coke meets the requirements of the petroleum coke industry standard NB/SH/T0527-2015 petroleum coke (green coke), and is not lower than the performance of the ordinary petroleum coke No. 1 required by the standard.

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

(1) according to the invention, raw oil with high metal content is used as a raw material, and decomposition and removal are carried out by utilizing the chemical characteristics of the raw oil according to the existence form of metal components in the raw oil through the arrangement of two-stage coking units, so that the raw oil is prevented from entering petroleum coke products, and high-quality petroleum coke meeting the technical requirements is prepared;

(2) the oil gas component obtained by two-stage coking is fractionated to obtain various distillate oil, so that the utilization value of the raw material residual oil is greatly improved;

(3) the device has the advantages of simple structure, simple and convenient operation method, low equipment and operation cost, reduction of the production cost of petroleum coke products and suitability for large-scale application.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for preparing petroleum coke from a high metal content feedstock oil according to example 1 of the present invention;

wherein, 1-the first preheating device, 2-the first coke tower, 3-the second preheating device, 4-the second coke tower, and 5-the fractionating tower.

Detailed Description

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the present invention, which is defined by the claims.

The invention provides a device and a method for preparing petroleum coke from high-metal-content raw oil, wherein the device comprises a primary coking unit, a secondary coking unit and a fractionation unit, wherein a top outlet of the primary coking unit is connected with an inlet of the secondary coking unit through the bottom of the fractionation unit, and a top outlet of the secondary coking unit is connected with an inlet of the fractionation unit; each stage of coking unit comprises a preheating device and a coke drum, wherein the outlet of the preheating device is connected with the inlet of the coke drum.

The method comprises the following steps:

(1) preheating the high-metal content raw oil, and then carrying out mild thermal cracking to obtain coke and first-stage coking oil gas;

(2) the first-stage coking oil gas obtained in the step (1) is heated again after heat and mass transfer at the bottom of the fractionation unit for cracking and coke formation reaction to obtain petroleum coke and second-stage coking oil gas;

(3) and (3) fractionating the secondary coking oil gas obtained in the step (2) to obtain gas, light oil and heavy oil, and returning part of the heavy oil to the step (2) for reaction.

The following are typical but non-limiting examples of the invention: