A process for the production of petroleum coke

Abstract

The present application provides a kind of petroleum coke production process, the production process includes the following steps: (1) first raw material is heated and enters the delayed coking device and is reacted, when reaction time reaches 10-60% of the entire reaction cycle, preferably 20-40%, first raw material feeding is stopped; (2) the second raw material is heated and sent into the delayed coking device and is reacted, and the oil gas stream generated by reaction is further fractionated after reaction to obtain petroleum coke.The present application solves the problem of ethylene tar treatment, and can significantly improve the problem of high volatile content of petroleum coke obtained from ethylene tar as raw material, and can reduce the coking tendency of heating furnace tube, prolong the operation cycle of heating furnace.

Description

Technical Field

[0001] This invention belongs to the field of petroleum refining technology and relates to a petroleum coke production process, particularly a production process for preparing high-grade petroleum coke using oil slurry and ethylene tar as raw materials. Background Technology

[0002] With dwindling oil resources, the rational utilization of these limited resources is of paramount importance to the oil refining industry. Ethylene tar, rich in polycyclic aromatic hydrocarbons, readily condenses into coke through thermal reactions, making it a high-quality raw material for petroleum coke production. However, its high asphaltenes content severely limits its industrial processing.

[0003] CN109207186A discloses a delayed coking method and the coking liquid and / or coke obtained by the method. The method includes injecting coking feed heated by a heating furnace into a coking tower for delayed coking to obtain coke and coking oil and gas. The coking oil and gas are separated to obtain coking gas, coking gasoline, coking diesel and coking wax oil. The coking feed includes coking raw materials and ethylene tar distillate.

[0004] CN104449799A discloses a method for producing high-purity petroleum coke from ethylene tar, comprising the following steps: mixing ethylene tar with light component oil at a weight ratio of 1:0.05 to 0.2, and then sending the mixture to a cracking coking furnace for distillation; or mixing 70% of the heavy component separated from the flash distillation of ethylene tar with light component oil at a weight ratio of 1:0.05 to 0.2, and then sending the mixture to a delayed coking tower for coking, thereby producing high-purity petroleum coke.

[0005] CN113122330A discloses a method and system for preparing petroleum coke from catalytic oil slurry and ethylene tar. The method includes the following steps: the catalytic oil slurry is desolidified to obtain pull-out oil and tail oil. The pull-out oil is hydrotreated. The reaction products are separated to obtain hydrotreated heavy distillate oil and ethylene tar, which are then heated and fed into a delayed coking unit for reaction. When the reaction time reaches 1% to 50% of the entire reaction cycle, the ethylene tar feed is stopped. The coking reaction products are separated to obtain gas, light oil, and heavy oil. The light oil is polymerized and mixed with the hydrotreated heavy distillate oil, heated, and then fed into the delayed coking unit for reaction. The heavy oil is recycled back to be mixed with the catalytic oil slurry for desolidification treatment. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention provides a petroleum coke production process. On the one hand, it provides a high-value-added production process for ethylene tar, solving the problem of ethylene tar processing. On the other hand, it significantly improves the problem of high volatile content in petroleum coke obtained from ethylene tar as raw material, reduces the tendency of coking in furnace tubes, and extends the operating cycle of the furnace. At the same time, it improves the product circulation stability by optimizing coking feedstock.

[0007] This invention provides a process for producing petroleum coke, the process comprising the following steps:

[0008] (1) The first raw material is heated and then enters the delayed coking unit for reaction. When the reaction time reaches 10-60% of the entire reaction cycle, preferably 20-40%, the feeding of the first raw material is stopped.

[0009] (2) The second raw material is heated and then fed into a delayed coking unit for reaction. After the reaction is completed, petroleum coke is obtained, and the oil and gas stream generated by the reaction is further fractionated.

[0010] Preferably, as some specific embodiments, the first raw material in step (1) can be a petroleum-based raw material and / or a coal-based raw material, wherein the petroleum-based raw material can be one or more of catalytic slurry, residual oil, and hydrotreated tail oil, preferably catalytic slurry; the coal-based raw material can be one or more of coal tar, coal liquefaction residue, and coal tar pitch.

[0011] Preferably, as some specific embodiments, the delayed coking device in step (1) generally includes at least one heating furnace, one fractionation tower and two coke towers, wherein at least one coke tower is always in the reaction stage and at least one coke tower is in the decoking stage.

[0012] Preferably, as some specific embodiments, in step (1), the first raw material is heated to a predetermined temperature and then enters the delayed coking device. At this time, the outlet temperature of the heating furnace is controlled to be 470-550°C, preferably 490-515°C.

[0013] Preferably, as some specific embodiments, the second raw material in step (2) is ethylene tar, which is a by-product obtained from the production of ethylene by cracking hydrocarbons.

[0014] Preferably, as some specific embodiments, in step (2), the second raw material is heated to a predetermined temperature and then enters the delayed coking device. At this time, the outlet temperature of the heating furnace is controlled to be 350-490°C, preferably 400-470°C, and more preferably 430-460°C.

[0015] Preferably, as some specific embodiments, the reaction conditions of the delayed coking unit are: the pressure at the top of the coke tower is 0.01 to 2.5 MPa, preferably 0.5 to 1.0 MPa, and the residence time of the material in the coking unit is 10 to 50 hours, preferably 14 to 38 hours.

[0016] Preferably, as some specific implementations, in step (2), after the second raw material is fed, an inert atmosphere is simultaneously introduced for purging. The inert atmosphere can be nitrogen and / or an inert gas, and the inert gas can be at least one of helium, neon, argon, krypton, and xenon. The purging operation is generally performed every 0.1 to 1 hour for 0.2 to 1 hour, preferably every 0.2 to 0.8 hours for 0.3 to 0.6 hours.

[0017] Preferably, as some specific embodiments, the ratio of the first raw material to the second raw material by weight is 1:2 to 1:0.01, preferably 1:1 to 1:0.25.

[0018] Preferably, as some specific implementations, the oil and gas stream generated in step (2) is further fractionated and separated to obtain coking gas, coking gasoline, coking diesel and heavy oil. The heavy oil can be recycled back to the delayed coking unit for further processing.

[0019] A second aspect of the present invention provides petroleum coke obtained using the above-described production process.

[0020] Preferably, as some specific embodiments, the volatile matter content of petroleum coke is 6-10%.

[0021] Preferably, as some specific embodiments, when petroleum coke products are used as a negative electrode material, the capacity can still be maintained at 328-348 mAh / g after 10,000 cycles at a 0.1 rate.

[0022] Compared with the prior art, the petroleum coke production process provided by the present invention has the following beneficial effects, specifically including:

[0023] Because ethylene tar contains high levels of unsaturated hydrocarbons such as olefins and alkynes, as well as heterocyclic compounds, it is chemically reactive and has poor oxidation stability. As a coking feedstock, it is prone to self-polymerization and condensation during the reaction process, generating new secondary asphaltenes and other substances. This easily leads to scaling and coking in the heat exchange system, pipelines, and heating furnace tubes of the coking unit, seriously affecting the stable operation and operating cycle of the unit. Existing methods mainly suppress coking by reducing the feed temperature (such as controlling the outlet temperature of the heating furnace). However, the applicant's research found that reducing the temperature causes a rapid increase in the volatile matter content of petroleum coke products, affecting the subsequent utilization of petroleum coke, limiting its application scenarios, and significantly reducing the product value. This prominent contradiction severely restricts the high-value utilization of ethylene tar. The applicant has adjusted the petroleum coke production process through research, and by using a tiered feeding method for the first and second raw materials, it has achieved high-value utilization of ethylene tar, improved the volatile matter content of petroleum coke products, solved the problem of coking in furnace tubes, and extended the operating cycle of the heating furnace. Moreover, through the tiered feeding method, the second raw material will form an embedded structure in the polymerization reaction. The presence of a certain embedded structure in the petroleum coke products can improve their cycle stability as graphite anodes for lithium batteries and increase their applicability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the petroleum coke production process of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0026] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0027] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (e.g., rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0028] In this document, all numeric values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0029] In this paper, volatile matter was determined using the SH_T0026-90 method.

[0030] In this paper, the properties of the first feedstock, catalytic slurry, and the second feedstock, ethylene tar, are shown in Table 1.

[0031] Electrochemical performance evaluation test:

[0032] The obtained petroleum coke was graphitized at 2900℃. The graphitized petroleum coke samples were assembled into button cells according to the relevant requirements of standard GB / T 24533-2019. Constant current charge-discharge tests were performed according to the current density and voltage in the standard, and the cells were cycled 10,000 times.

[0033] In this paper, the capacity of petroleum coke graphitized batteries was determined using the method in GB / T 24533-2019.

[0034] like Figure 1 As shown, the petroleum coke production process provided by this invention is as follows: High-pressure steam 3 is heated by a heater 4 and then enters the coke tower 6 of the delayed coking unit via pipeline 5 for tower warming. After the tower warming is completed, the first raw material 1 is heated by the heater 4 and then enters the coke tower 6 via pipeline 5. After a certain feeding time, the feeding of the first raw material 1 is stopped. The second raw material 2 is heated by the heater 4 and then enters the coke tower 6 of the delayed coking unit via pipeline 5. It is mixed with the first raw material that has already reacted and continues to carry out the polymerization reaction. During the polymerization reaction, an inert atmosphere 13 is introduced into the coke tower 6 of the delayed coking unit via pipeline at a certain period to purge. The oil and gas generated by the reaction flows through the coking oil and gas pipeline 7 and enters the fractionation tower 8. After separation, coking gas 9, coking gasoline 10, coking diesel 11 and heavy oil 12 are obtained. The heavy oil 12 is circulated back to the delayed coking unit 6 via pipeline 5 for processing. Petroleum coke product is obtained at the bottom of the coke tower.

[0035] Table 1 Properties of Raw Materials

[0036] Property Indicators Catalytic slurry Ethylene tar <![CDATA[Density, g / cm 3 > 1.0378 1.0732 Ash content, wt% 0.049 0.010 C, wt% 89.85 91.38 H, wt% 8.76 6.71 S, wt% 0.52 0.14 <![CDATA[N,μg ˙ g -1 ]]> 0.09 0.04 Four components, wt% Saturated fraction 7.9 10.4 Aromatic components 82.9 61.1 gelatin 7.9 27.8 Asphalt 1.3 0.7

[0037] Example 1

[0038] Example 1 uses the present invention Figure 1The process flow shown is as follows: when the catalytic oil slurry is fed, the outlet temperature of the heater is controlled at 515℃, and then it enters the coking unit for polymerization reaction. The pressure (absolute pressure) is 1MPa and the residence time is 26h. After the catalytic oil slurry reaction is completed, ethylene tar is fed after heating. At this time, the outlet temperature of the heater is controlled at 460℃. The reaction conditions of the coking unit are: pressure (absolute pressure) 1MPa, residence time 30h; the mass ratio of catalytic oil slurry to ethylene tar feed is 1:1; after the reaction, petroleum coke is obtained with a volatile content of 6.1%. According to the electrochemical evaluation method, it is made into a lithium button battery, and the capacity is maintained at 348mAh / g after 10,000 cycles.

[0039] Example 2

[0040] Example 2 uses the present invention Figure 1 The process flow shown is as follows: when the catalytic oil slurry is fed, the outlet temperature of the heater is controlled at 495℃, and then it enters the coking unit for polymerization reaction. The pressure (absolute pressure) is 1.5MPa, and the residence time is 18h. After the catalytic oil slurry reaction is completed, ethylene tar is fed after heating. At this time, the outlet temperature of the heater is controlled at 440℃. The reaction conditions of the coking unit are: pressure (absolute pressure) 1MPa, residence time 38h; the mass ratio of catalytic oil slurry to ethylene tar feed is 1:1; after the reaction, petroleum coke is obtained with a volatile content of 7.3%. According to the electrochemical evaluation method, it is made into a lithium button battery, and the capacity is maintained at 345mAh / g after 10,000 cycles.

[0041] Example 3

[0042] Example 3 uses the present invention Figure 1 The process flow shown is as follows: when the catalytic oil slurry is fed, the outlet temperature of the heater is controlled at 460℃, and then it enters the coking unit for polymerization reaction. The pressure (absolute pressure) is 0.5MPa, and the residence time is 28h. After the catalytic oil slurry reaction is completed, ethylene tar is fed after heating. At this time, the outlet temperature of the heater is controlled at 470℃. The reaction conditions of the coking unit are: pressure (absolute pressure) 0.5MPa, residence time 38h; mass ratio of catalytic oil slurry to ethylene tar is 1:1. After the reaction, petroleum coke is obtained with a volatile content of 8.0%. It is made into a lithium button battery according to the electrochemical evaluation method, and the capacity is maintained at 341mAh / g after 10,000 cycles.

[0043] Comparative Example 1

[0044] Comparative Example 1 uses the present invention Figure 1The process flow shown is as follows, but only ethylene tar is used as raw material. The ethylene tar is heated before being fed into the furnace. At this time, the outlet temperature of the heating furnace is controlled at 495℃. The reaction conditions of the coking unit are: pressure (absolute pressure) of 1MPa and residence time of 20h. During the experiment, the furnace tubes of the heating furnace were severely coked, and the experiment could not proceed smoothly.

[0045] Comparative Example 2

[0046] Comparative Example 2 uses the present invention Figure 1 The process flow shown uses only ethylene tar as raw material. The ethylene tar is heated before being fed into the furnace, and the outlet temperature of the furnace is controlled at 460°C. The reaction conditions of the coking unit are: reaction temperature 480°C, pressure (absolute pressure) 1 MPa, and residence time 30 h. After the reaction, petroleum coke is obtained with a volatile content of 18.2%. It is made into a lithium button battery according to the electrochemical evaluation method, and the capacity is maintained at 298 mAh / g after 10,000 cycles.

[0047] Comparative Example 3

[0048] In Comparative Example 3, catalytic oil slurry and ethylene tar were mixed evenly at a mass ratio of 1:1 and then heated before being fed into the furnace. At this time, the outlet temperature of the heating furnace was controlled at 490°C, and the reaction conditions of the coking unit were: pressure (absolute pressure) of 1 MPa and residence time of 30 h. During the experiment, the furnace tubes of the heating furnace were severely coked, and the experiment could not proceed smoothly.

[0049] Comparative Example 4

[0050] In Comparative Example 4, ethylene tar was first fed after heating, with the outlet temperature of the heater controlled at 460°C. The reaction conditions of the coking unit were: pressure (absolute pressure) of 1 MPa and residence time of 30 h. After the ethylene tar reaction was completed, the catalytic slurry was heated (heater outlet temperature of 515°C) and then entered the coking unit at atmospheric pressure for a residence time of 40 h. After the reaction was completed, petroleum coke was obtained with a volatile content of 19.4%. It was made into a lithium button battery according to the electrochemical evaluation method, and the capacity remained at 286 mAh / g after 10,000 cycles.

[0051] Comparative Example 5

[0052] In Comparative Example 5, the catalytic slurry was heated before being fed into the coking unit. At this time, the outlet temperature of the heater was controlled at 515°C. The reaction conditions of the coking unit were: pressure (absolute pressure) of 1 MPa and residence time of 40 h. After the ethylene tar reaction was completed, the ethylene tar was heated (heater outlet temperature of 460°C) and then entered the coking unit at atmospheric pressure. The feeding was stopped after the reaction time of the ethylene tar feed accounted for 70% of the entire reaction cycle. After the reaction was completed, petroleum coke was obtained with a volatile content of 17.6%. It was made into a lithium button battery according to the electrochemical evaluation method, and the capacity remained at 305 mAh / g after 10,000 cycles.

Claims

1. A petroleum coke production process, the production process comprising the following steps: (1) a first raw material is heated and then fed into a delayed coking device to react, and when the reaction time reaches 10-60% of the entire reaction period, the feeding of the first raw material is stopped; the first raw material is a petroleum-based raw material and / or a coal-based raw material, the petroleum-based raw material is one or more of catalytic slurry oil, residual oil, and hydrocracking tail oil; the coal-based raw material is one or more of coal tar, coal liquefaction residue, and coal tar pitch; (2) a second raw material is heated and then fed into the delayed coking device to react, and after the reaction, petroleum coke is obtained, and the oil gas stream generated in the reaction is further fractionated; the second raw material is ethylene tar; The reaction conditions of the delayed coking device are as follows: the pressure at the top of the coke drum is 0.01-2.5 MPa, and the residence time of the material in the coking device is 10-50 h.

2. The petroleum coke production process according to claim 1, characterized in that: The petroleum-based raw material is catalytic slurry oil.

3. The petroleum coke production process according to claim 1, characterized in that: When the reaction time reaches 20-40% of the entire reaction period, the feeding of the first raw material is stopped.

4. The petroleum coke production process according to claim 1, characterized in that: The delayed coking device in step (1) comprises at least one heating furnace, one fractionating column, and two coke drums, and at least one coke drum is always kept in the reaction stage and at least one coke drum is kept in the decoking stage.

5. The petroleum coke production process according to claim 1, characterized in that: In step (1), the first raw material is heated to a predetermined temperature and then fed into the delayed coking device, and at this time, the outlet temperature of the heating furnace is controlled to be 470-550°C.

6. The petroleum coke production process according to claim 1, characterized in that: In step (1), the first raw material is heated to a predetermined temperature and then fed into the delayed coking device, and at this time, the outlet temperature of the heating furnace is controlled to be 490-515°C.

7. The petroleum coke production process according to claim 1, characterized in that: In step (2), the second raw material is heated to a predetermined temperature and then fed into the delayed coking device, and at this time, the outlet temperature of the heating furnace is controlled to be 350-490°C.

8. The petroleum coke production process according to claim 1, characterized in that: In step (2), the second raw material is heated to a predetermined temperature and then fed into the delayed coking device, and at this time, the outlet temperature of the heating furnace is controlled to be 400-470°C.

9. The process for producing petroleum coke according to claim 1, characterized in that: In step (2), the second raw material is heated to a predetermined temperature and then fed into the delayed coking device, and at this time, the outlet temperature of the heating furnace is controlled to be 430-460°C.

10. The process for producing petroleum coke according to claim 1, characterized by: The reaction conditions of the delayed coking device are as follows: the pressure at the top of the coke drum is 0.5-1.0 MPa.

11. The process for producing petroleum coke according to claim 1, characterized in that: The reaction conditions of the delayed coking device are as follows: the residence time of the material in the coking device is 14-38 h.

12. The process for producing petroleum coke according to claim 1, characterized by: In step (2), after the feeding of the second raw material is started, an inert atmosphere is introduced for purging, the inert atmosphere is nitrogen and / or an inert gas, the inert gas is at least one of helium, neon, argon, krypton, and xenon; the purging operation is performed every 0.1-1 h, and the purging operation is performed for 0.2-1 h every time.

13. The process for producing petroleum coke according to claim 1, characterized in that: In step (2), after the feeding of the second raw material is started, an inert atmosphere is introduced for purging, the inert atmosphere is nitrogen and / or an inert gas, the inert gas is at least one of helium, neon, argon, krypton, and xenon; the purging operation is performed every 0.2-0.8 h, and the purging operation is performed for 0.3-0.6 h every time.

14. The process for producing petroleum coke according to claim 1, characterized in that: The ratio of the first raw material to the second raw material is 1:2-1:0.01 on the basis of weight ratio.

15. The process for producing petroleum coke according to claim 1, characterized in that: The ratio of the first raw material to the second raw material is 1:1-1:0.25 on the basis of weight ratio.

16. The process for producing petroleum coke according to claim 1, characterized in that: The oil gas stream generated in step (2) is separated by fractional distillation to obtain coking gas, coking gasoline, coking diesel and heavy oil, and the heavy oil is recycled to the delayed coking device for treatment.

17. A petroleum coke obtained by the production process according to any one of claims 1 to 16.

18. The petroleum coke according to claim 17, characterized in that: The volatile content of the petroleum coke is 6-10%.

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