Petroleum coke production process

Abstract

The invention provides a petroleum coke production process which comprises the following steps: (1) heating a first raw material, feeding the heated first raw material into a delayed coking device for reaction, and stopping feeding the first raw material when the reaction time reaches 10-60%, preferably 20-40%, of the whole reaction period; and (2) heating the second raw material, feeding the heated second raw material into a delayed coking device, reacting to obtain petroleum coke after the reaction is finished, and further fractionating an oil-gas material flow generated by the reaction. The process provided by the invention solves the problem of ethylene tar treatment on one hand, can obviously improve the problem of high volatile component content of petroleum coke obtained by taking ethylene tar as a raw material, can reduce the coking tendency of a furnace tube of a heating furnace, and prolongs the operation period of the heating furnace.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum refining, and relates to a petroleum coke production process, in particular to a production process for preparing high-grade petroleum coke by taking oil slurry and ethylene tar as raw materials. Background Art

[0002] As petroleum resources are gradually decreasing, it is particularly important for the oil refining industry to make good use of limited petroleum resources. Ethylene tar is rich in polycyclic aromatic hydrocarbons and easily condenses to form coke after thermal reaction. It is a high-quality raw material for producing petroleum coke, but it contains a large amount of asphaltene, which seriously limits its industrial processing.

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

[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 in a weight ratio of 1:0.05-0.2, and sending the mixture to a cracking coking furnace for distillation; or mixing 70% of the heavy components separated by flash distillation of ethylene tar with light component oil in a weight ratio of 1:0.05-0.2, and 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 comprising the following contents: the catalytic oil slurry is subjected to desolidification treatment to obtain pulled oil and tail oil, the pulled oil is subjected to hydrogenation treatment, the reaction products are separated to obtain hydrogenated heavy distillate oil and ethylene tar, which are respectively heated and enter a delayed coking device for reaction, when the reaction time reaches 1% to 50% of the entire reaction cycle, the ethylene tar feed is stopped, and the coking reaction products are separated to obtain gas, light oil and heavy oil; the light oil is subjected to polymerization reaction, mixed with the hydrogenated heavy distillate oil, heated and enters a delayed coking device for reaction, and the heavy oil is circulated back and mixed with the catalytic oil slurry for desolidification treatment. Summary of the invention

[0006] In view of the deficiencies in the prior art, the technical solution of the present invention is to provide a petroleum coke production process, which can, on the one hand, provide a high value-added production process for ethylene tar and solve the problem of ethylene tar treatment. The main thing is to significantly improve the problem of high volatile matter content in petroleum coke obtained from ethylene tar as raw material, and can also reduce the coking tendency of the heating furnace tubes and extend the operating cycle of the heating furnace; at the same time, the product cycle stability is improved by optimizing the coking raw materials.

[0007] The present invention provides a petroleum coke production process, which comprises the following steps:

[0008] (1) After being heated, the first raw material enters the delayed coking device for reaction. When the reaction time reaches 10 to 60% of the entire reaction cycle, preferably 20 to 40%, the feeding of the first raw material is stopped;

[0009] (2) The second raw material is heated and then sent to a delayed coking device 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 oil slurry, residual oil, and hydrogenated tail oil, preferably catalytic oil 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 distillation tower and two coke towers, and the coke towers always keep at least one coke tower in the reaction stage and at least one coke tower 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 a delayed coking device, and 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, and the ethylene tar is a by-product obtained by cracking hydrocarbons to produce ethylene.

[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, and 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 device are: the top pressure of the coke tower is 0.01-2.5 MPa, preferably 0.5-1.0 MPa, and the residence time of the material in the coking device is 10-50 h, preferably 14-38 h.

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

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

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

[0019] The second aspect of the present invention provides a petroleum coke obtained by the above production process.

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

[0021] Preferably, as some specific embodiments, the petroleum coke product is used as the negative electrode material and is cycled 10,000 times at a rate of 0.1, and the capacity can still be maintained at 328 to 348 mAh / g.

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

[0023] Since ethylene tar contains high levels of unsaturated hydrocarbons and heterocyclic compounds such as olefins and alkynes, active chemical properties and poor oxidative stability, it is very easy to undergo self-polymerization and condensation during the reaction as a coking raw material, and to produce new colloids and asphaltene, which can easily cause scaling and coking of the heat exchange system, pipelines and heating furnace tubes of the coking unit, seriously affecting the stable operation and start-up cycle of the unit. The existing method mainly suppresses the coking problem by lowering the feed temperature (such as controlling the outlet temperature of the heating furnace), but the applicant found during the research process that lowering the temperature will cause the volatile matter of the petroleum coke product to increase rapidly, affecting the subsequent utilization of the petroleum coke, limiting its use scenarios, and greatly reducing the product value. This prominent contradiction seriously restricts the high value-added utilization of ethylene tar. The applicant has adjusted the petroleum coke production process through research. Through the step-by-step feeding method of the first raw material and the second raw material, on the one hand, the high value-added utilization of ethylene tar is achieved, the volatile matter of the petroleum coke product is improved, and at the same time the problem of coking in the furnace tube is solved, and the operation cycle of the heating furnace is extended. Moreover, through the step-by-step feeding method, the second raw material will form a mosaic structure in the polymerization reaction. The petroleum coke product contains a certain mosaic structure, which can improve its cycle stability as a graphite negative electrode for lithium batteries and increase its applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the petroleum coke production process of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0026] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0027] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different orientations of the object in use or operation in addition to the orientation depicted in the figure. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both the below and above directions. Objects may also have other orientations (e.g., rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0028]

[0043] All numerical values ​​for parameters (eg, amounts or conditions) herein are to be understood as being modified in all instances by the term "about," whether or not "about" actually appears before the numerical value.

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

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

[0031] Electrochemical performance evaluation test:

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

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

[0034] like Figure 1 As shown, the petroleum coke production process provided by the present invention is as follows: high-pressure steam 3 is heated by a heating furnace 4 and then enters a coke tower 6 of a delayed coking device through a pipeline 5 for a tower warming operation. After the tower warming operation is completed, a first raw material 1 is heated by a heating furnace 4 and then enters a coke tower 6 through a pipeline 5. After a certain period of feeding, the feeding of the first raw material 1 is stopped, and a second raw material 2 is heated by a heating furnace 4 and then enters a coke tower 6 of a delayed coking device through a pipeline 5, and is mixed with the first raw material that has been reacted to continue the polymerization reaction. During the polymerization reaction, an inert atmosphere 13 is entered into the coke tower 6 of the delayed coking device through a pipeline at a certain period for purging. The oil and gas generated by the reaction flows through a coking oil and gas pipeline 7 and enters a 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 device 6 through a pipeline 5 for treatment, and a petroleum coke product is obtained at the bottom of the coke tower.

[0035] Table 1 Raw material properties

[0036] Nature indicators Catalytic slurry Ethylene tar <![CDATA[Density, g / cm 3 > 1.0378 1.0732 Ash, 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% Saturation 7.9 10.4 Aroma 82.9 61.1 Gel 7.9 27.8 Asphaltene 1.3 0.7

[0037] Example 1

[0038] Embodiment 1 adopts the present invention Figure 1As shown in the process flow, when catalytic oil slurry is fed, the outlet temperature of the heating furnace is controlled to be 515°C, 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 heated and fed, at this time the outlet temperature of the heating furnace is controlled to be 460°C, and the reaction conditions of the coking unit are: pressure (absolute pressure) is 1MPa, residence time is 30h; the mass ratio of catalytic oil slurry and ethylene tar feed is 1:1; after the reaction, petroleum coke is obtained, the volatile matter content of which is 6.1%, and a lithium button battery is made according to the electrochemical evaluation method, and the capacity is maintained at 348mAh / g after 10,000 cycles.

[0039] Example 2

[0040] Embodiment 2 adopts the present invention Figure 1 As shown in the process flow, when catalytic oil slurry is fed, the outlet temperature of the heating furnace is controlled to be 495°C, 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 heated and fed, and the outlet temperature of the heating furnace is controlled to be 440°C. At this time, the reaction conditions of the coking unit are: pressure (absolute pressure) is 1MPa, and the residence time is 38h; the mass ratio of catalytic oil slurry and ethylene tar feed is 1:1; after the reaction, petroleum coke is obtained, the volatile matter content of which is 7.3%, and a lithium button battery is made according to the electrochemical evaluation method, and the capacity is maintained at 345mAh / g after 10,000 cycles.

[0041] Example 3

[0042] Embodiment 3 adopts the present invention Figure 1 As shown in the process flow, when catalytic oil slurry is fed, the outlet temperature of the heating furnace is controlled to be 460°C, 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 heated and fed, and the outlet temperature of the heating furnace is controlled to be 470°C. At this time, the reaction conditions of the coking unit are: pressure (absolute pressure) is 0.5MPa, and the residence time is 38h; the mass ratio of catalytic oil slurry and ethylene tar is 1:1; after the reaction, petroleum coke is obtained, the volatile matter content of which is 8.0%, and a lithium button battery is made 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: Figure 1The process flow shown in the figure only uses ethylene tar as raw material. The ethylene tar is fed after being heated. At this time, the outlet temperature of the heating furnace is controlled to be 495°C. The reaction conditions of the coking unit are: pressure (absolute pressure) is 1MPa, and the residence time is 20h. During the experiment, the heating furnace tubes are severely coked and the experiment cannot be carried out smoothly.

[0045] Comparative Example 2

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

[0047] Comparative Example 3

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

[0049] Comparative Example 4

[0050] In Comparative Example 4, ethylene tar is heated and then fed in advance. At this time, the outlet temperature of the heating furnace is controlled to be 460°C, and the reaction conditions of the coking unit are: pressure (absolute pressure) is 1MPa, and the residence time is 30h; after the reaction of ethylene tar is completed, the catalytic oil slurry is heated (the outlet temperature of the heating furnace is 515°C) and enters the coking unit at normal pressure for a residence time of 40h. After the reaction is completed, petroleum coke is obtained, and the volatile matter content is 19.4%. According to the electrochemical evaluation method, a lithium button battery is made, and the capacity is maintained at 286mAh / g after 10,000 cycles.

[0051] Comparative Example 5

[0052] In Comparative Example 5, the catalytic oil slurry is heated and then fed. At this time, the outlet temperature of the heating furnace is controlled to be 515°C, and the reaction conditions of the coking unit are: pressure (absolute pressure) is 1MPa, and the residence time is 40h; after the reaction of ethylene tar is completed, the ethylene tar is heated (the outlet temperature of the heating furnace is 460°C) and then enters the coking unit at normal pressure. The reaction time after the ethylene tar is fed accounts for 70% of the entire reaction cycle, and then the feeding is stopped. After the reaction is completed, petroleum coke is obtained, and the volatile matter content is 17.6%. According to the electrochemical evaluation method, a lithium button battery is made, and the capacity is maintained at 305mAh / g after 10,000 cycles.

Claims

1. A petroleum coke production process, the production process comprising the following steps: (1) After being heated, the first raw material enters the delayed coking device for reaction. When the reaction time reaches 10 to 60% of the entire reaction cycle, preferably 20 to 40%, the feeding of the first raw material is stopped; (2) The second raw material is heated and then sent to 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.

2. The petroleum coke production process according to claim 1, characterized in that: The first raw material in step (1) is a petroleum-based raw material and / or a coal-based raw material, wherein the petroleum-based raw material is one or more of catalytic oil slurry, residual oil, and hydrogenated tail oil, preferably catalytic oil slurry; the coal-based raw material is one or more of coal tar, coal liquefaction residue, and coal tar pitch.

3. 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 tower and two coke towers, wherein at least one coke tower is always kept in a reaction stage and at least one coke tower is always kept in a decoking stage.

4. 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 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.

5. The petroleum coke production process according to claim 1, characterized in that: The second raw material in step (2) is ethylene tar.

6. 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 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.

7. The petroleum coke production process according to claim 1, characterized in that: The reaction conditions of the delayed coking device are as follows: the pressure at the top of the coking 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 device is 10 to 50 hours, preferably 14 to 38 hours.

8. The petroleum coke production process according to claim 1, characterized in that: After the second raw material is started to be fed in step (2), an inert atmosphere is introduced for purging at the same time. The inert atmosphere is nitrogen and / or an inert gas, and the inert gas is at least one of helium, neon, argon, krypton, and xenon. The purging operation is performed every 0.1 to 1 hour for 0.2 to 1 hour, and preferably every 0.2 to 0.8 hours for 0.3 to 0.6 hours.

9. The petroleum coke production process according to claim 1, characterized in that: Based on the weight ratio, the ratio of the first raw material to the second raw material is 1:2 to 1:0.01, preferably 1:1 to 1:0.

25.

10. The petroleum coke production process according to claim 1, characterized in that: The oil and gas stream generated by the reaction in step (2) is fractionated and separated to obtain coking gas, coking gasoline, coking diesel and heavy oil, and the heavy oil is recycled to the delayed coking unit for treatment.

11. Petroleum coke obtained by the production process described in any one of claims 1 to 10.

12. The petroleum coke according to claim 11, characterized in that: The volatile matter of petroleum coke is 6-10%.

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