A method and system for the resource utilization of petroleum coke

Abstract

This invention relates to a method and system for the resource utilization of petroleum coke, belonging to the field of petroleum fractionation technology. The method includes the following steps: calcining a first portion of petroleum coke to obtain high-temperature flue gas and calcined coke; pyrolyzing a second portion of petroleum coke using the high-temperature flue gas as a heat source to obtain pyrolytic coke, pyrolytic gas, and low-temperature flue gas; mixing the pyrolytic coke with the first portion of petroleum coke for calcination; condensing the pyrolytic gas to obtain tar; using the low-temperature flue gas as a heat source, hot-pressing the calcined coke, coal tar pitch, and tar as raw materials to prepare a prebaked anode; and calcining the hot-pressed prebaked anode using the condensed pyrolytic gas as fuel to obtain the prebaked anode product. The high-temperature flue gas generated from the calcination of the first portion of petroleum coke is used for the pyrolysis of the second portion of petroleum coke; the residual gas phase after condensation of the pyrolytic gas is used in the calcination process of the prebaked anode. This method achieves multi-stage utilization of petroleum coke, high-temperature flue gas, and pyrolytic gas, resulting in energy-saving effects.

Description

Technical Field

[0001] This invention belongs to the field of energy substitution and energy conservation and emission reduction technology, and specifically relates to a method and system for the resource utilization of petroleum coke. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Petroleum coke is a byproduct of crude oil refining. It is produced by separating light and heavy oils during crude oil distillation, and then converting the heavy oil through thermal cracking. Its main elemental composition is carbon, accounting for over 80%, with 1.5%-8% hydrogen, and the remainder consisting of oxygen, nitrogen, sulfur, and metallic elements. Depending on its sulfur content, it can be used as fuel in thermal power plants and cement plants, and also in carbon materials such as prebaked anodes and graphite electrodes used in aluminum and steelmaking.

[0004] The general process in the prebaked anode industry is as follows: petroleum coke is calcined in a calcining furnace (tank or rotary type) to produce calcined coke. The calcined coke and coal tar pitch are then combined and calcined in an annular roasting furnace to obtain the final product. For the tank calcining furnace, the heat comes from the volatiles released during the calcination process of the petroleum coke. The combustion of these volatiles produces high-temperature flue gas, which powers the tank calcining furnace and allows for waste heat recovery for power generation or steam production. The annular roasting furnace uses natural gas and the heat released from the combustion of volatiles during its own roasting process as its heat source, consuming 45–65 Nm³ of natural gas per ton of product. 3 Currently, the entire prebaked anode production system generally suffers from low levels of intensification and unreasonable energy use, resulting in lower economic output. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for the resource utilization of petroleum coke. The method involves calcining and pyrolyzing petroleum coke according to a set ratio. The high-temperature flue gas generated from calcination and the pyrolysis gas generated from pyrolysis are utilized in multiple stages to prepare products such as calcined coke and prebaked anodes, thereby achieving resource utilization.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] Firstly, a method for the resource utilization of petroleum coke includes the following steps:

[0008] S1. The first part of the petroleum coke is calcined to obtain high-temperature flue gas at 1000-1450℃ and calcined coke;

[0009] S2. The second part of the petroleum coke is pyrolyzed using high-temperature flue gas as a heat source to obtain pyrolysis coke, pyrolysis gas and low-temperature flue gas at 200-250℃.

[0010] S3. Mix the pyrolysis coke with the first part of petroleum coke and calcine it.

[0011] S4. Condensate the pyrolysis gas to obtain tar;

[0012] S5. Using low-temperature flue gas as a heat source, and calcined coke, coal tar pitch and tar as raw materials, prebaked anodes are prepared by hot pressing.

[0013] S6. Using condensed pyrolysis gas as fuel, the prebaked anode raw material after hot pressing is roasted to obtain the prebaked anode product.

[0014] The optional mass ratio of the first part of petroleum coke to the second part of petroleum coke is (5-7):(3:5).

[0015] Optionally, a set proportion of high-temperature flue gas can be used for waste heat power generation.

[0016] Optionally, in S1, the calcination temperature is 1000–1350℃.

[0017] Optionally, in S2, the pyrolysis temperature is 150–700℃, and the high-temperature flue gas is converted into low-temperature flue gas.

[0018] Optionally, in S3, pyrolytic coke and the first portion of petroleum coke are mixed and calcined.

[0019] Optionally, in S4, the pyrolysis gas is condensed at 300–400°C to obtain tar and residual gas phase.

[0020] Optionally, in S6, the prebaked anode is roasted using the gas phase obtained from the condensation of pyrolysis gas in S4 as fuel.

[0021] Optionally, in S6, other gaseous fuels are mixed in during the roasting process.

[0022] Optionally, in S6, the exhaust gas generated during the preparation of the prebaked anode and the flue gas emitted from waste heat power generation are purified before being discharged.

[0023] Secondly, a petroleum coke resource utilization system based on the above-mentioned petroleum coke resource utilization method includes a calcination device, a pyrolysis device, a condensation device, and a roasting device connected in sequence; the pyrolysis device and the condensation device are respectively connected to a prebaked anode forming device.

[0024] Optionally, the calcination device and the prebaked anode forming device are respectively connected to the flue gas purification device.

[0025] Optionally, the calcining furnace is connected to a flue gas purification device via a waste heat power generation device.

[0026] Optionally, the calcination unit is used to calcine petroleum coke to obtain high-temperature flue gas and calcined coke.

[0027] Optionally, the pyrolysis unit is used to pyrolyze petroleum coke to obtain pyrolysis gas and pyrolysis coke.

[0028] Optionally, a condensation unit is used to condense the pyrolysis gas to obtain tar and gaseous fuel.

[0029] Optionally, the prebaked anode forming apparatus is used to prepare prebaked anode raw materials of a predetermined shape.

[0030] Optionally, the calcining apparatus is used to calcine prebaked anode raw materials of a predetermined shape to obtain prebaked anodes.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention provides a method and system for the resource utilization of petroleum coke. The first part of the petroleum coke is calcined, and a portion of the high-temperature flue gas generated is used for the pyrolysis of the second part of the petroleum coke. The residual gas phase after condensation of the pyrolysis gas is used in the roasting process of prebaked anodes. The tar generated from condensation is used in the forming process of prebaked anodes, and the low-temperature flue gas converted from the high-temperature flue gas is used for heating in the forming process. The pyrolysis coke generated from pyrolysis is co-calcined with the first part of the petroleum coke, avoiding intermediate cooling. This achieves multi-stage utilization of petroleum coke, high-temperature flue gas, and pyrolysis gas. The pyrolysis gas replaces the natural gas required in the original roasting process, resulting in energy savings that are more valuable than the cost savings from combustion for power generation or steam production during the calcination process. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 This is a schematic diagram of the petroleum coke resource utilization system in Embodiment 2 of the present invention.

[0035] The components include: 1. calcination device; 2. pyrolysis device; 3. condensation device; 4. roasting device; 5. prebaked anode hot pressing device; 6. waste heat power generation device; and 7. flue gas purification device. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] In the following technical solutions, pyrolysis coke refers to the solid product obtained by heating and decomposing petroleum coke without contact with oxygen, with the volatile content reduced to below 5%, and the density, mechanical strength, electrical conductivity, chemical stability, and antioxidant properties improved.

[0039] Calcined coke refers to petroleum coke products that meet certain indicators (moisture content, true density, mechanical strength, electrical conductivity, and oxidation resistance, etc.) after being calcined at high temperature. In this invention, it refers to mixed calcined petroleum coke obtained by calcining petroleum coke and pyrolysis coke together.

[0040] Prebaked anodes refer to carbon blocks produced using petroleum coke, pitch coke, etc. as aggregates and coal tar pitch as a forming agent (binder). They are used as anode materials in prebaked aluminum electrolysis cells. The preparation method includes a forming process and a roasting process. In the forming process, the raw materials are mixed and prepared into a set shape. In the roasting process, the raw materials of the set shape obtained in the forming process are roasted into prebaked anode products.

[0041] A method for the resource utilization of petroleum coke includes the following steps:

[0042] S1. Calcining the first part of petroleum coke to obtain high-temperature flue gas and calcined coke;

[0043] S2. The second part of petroleum coke is pyrolyzed using high-temperature flue gas as a heat source to obtain pyrolytic coke, pyrolytic gas and low-temperature flue gas.

[0044] S3. Mix the pyrolysis coke with the first part of petroleum coke and calcine it.

[0045] S4. Condensate the pyrolysis gas to obtain tar;

[0046] S5. Using low-temperature flue gas as a heat source, and calcined coke, coal tar pitch and tar as raw materials, prebaked anodes are prepared by hot pressing.

[0047] S6. Using condensed pyrolysis gas as fuel, the prebaked anode after hot pressing is roasted to obtain the prebaked anode product.

[0048] In the above process, the high-temperature flue gas generated by calcination of petroleum coke is utilized in two steps: petroleum coke pyrolysis and prebaked anode forming. The pyrolysis gas generated by petroleum coke pyrolysis is used in the prebaked anode roasting process. The pyrolysis gas is separated to obtain tar, which replaces part of the coal tar pitch raw material in the prebaked anode forming process, thereby realizing the multi-step resource utilization of petroleum coke.

[0049] The optional mass ratio of the first part of petroleum coke to the second part of petroleum coke is (5-7):(3-5). This ratio mainly ensures that the high-temperature flue gas generated by calcination can achieve pyrolysis while having enough flue gas and heat to provide heat for the calcination process and generate electricity from waste heat, thus meeting the power demand of the plant.

[0050] Optionally, a set proportion of high-temperature flue gas can be used for waste heat power generation to provide electricity for the entire plant, while also producing steam and surplus electricity for external supply.

[0051] Optionally, in S1, the calcination temperature is 1000-1350℃, generating high-temperature flue gas at 1000-1450℃. Calcination can produce calcined coke, and the high-temperature flue gas can be utilized in multiple stages.

[0052] Optionally, in S2, the pyrolysis temperature is 150–700°C, producing pyrolysis coke and pyrolysis gas. The high-temperature flue gas is converted into low-temperature flue gas at 200–250°C, which can be utilized in the subsequent forming process of the roasted anode.

[0053] Optionally, in S3, the pyrolytic coke and the first part of petroleum coke are mixed and calcined. The pyrolytic coke is calcined in a state without cooling, which can avoid heat loss.

[0054] Optionally, in S4, the pyrolysis gas is condensed at 300-400℃ to obtain tar and residual gas phase. The residual gas phase obtained from the condensation of the pyrolysis gas is used as fuel for the prebaking process of the anode, so as to achieve full utilization of the pyrolysis gas.

[0055] Optionally, in S6, the prebaked anode is roasted using the gas phase obtained from the condensation of pyrolysis gas in S4 as fuel.

[0056] Optionally, in S6, other gaseous fuels, such as natural gas, are mixed in the pre-baking process to supplement the fuel quantity and obtain the set roasting temperature.

[0057] Optionally, in S6, the exhaust gas generated during the preparation of the prebaked anode is purified before being discharged, wherein the exhaust gas includes the exhaust gas generated during the roasting process and the flue gas emitted during the hot pressing process.

[0058] A petroleum coke resource utilization system based on the above-mentioned petroleum coke resource utilization method includes a calcination device, a pyrolysis device, a condensation device, and a roasting device connected in sequence; the pyrolysis device and the condensation device are respectively connected to a prebaked anode forming device.

[0059] Optionally, the calcination unit is used to calcine petroleum coke to obtain high-temperature flue gas and calcined coke.

[0060] Optionally, the pyrolysis unit is used to pyrolyze petroleum coke to obtain pyrolysis gas and pyrolysis coke.

[0061] Optionally, a condensation unit is used to condense the pyrolysis gas to obtain tar and gaseous fuel.

[0062] Optionally, the prebaked anode forming apparatus is used to prepare prebaked anode raw materials of a predetermined shape.

[0063] Optionally, the calcining apparatus is used to calcine prebaked anode raw materials of a predetermined shape to obtain prebaked anodes.

[0064] Optionally, the calcining device supplies high-temperature flue gas to the pyrolysis device; the pyrolysis device supplies pyrolysis coke to the calcining device, supplies pyrolysis gas to the condensing device, and supplies low-temperature flue gas to the prebaked anode forming device; the condensing device supplies tar to the prebaked anode forming device and supplies gaseous fuel to the calcining device.

[0065] Optionally, the roasting device and the prebaked anode forming device are respectively connected to a flue gas purification device to purify the roasting tail gas and the cooled low-temperature flue gas before emission.

[0066] Optionally, the calcining furnace is connected to a flue gas purification device via a waste heat power generation device. The high-temperature flue gas generates electricity through the waste heat power generation device to provide power for the entire plant, while also producing steam and surplus electricity for external supply.

[0067] Example 1

[0068] A method for the resource utilization of petroleum coke includes the following steps:

[0069] S1. The first part of the petroleum coke is calcined at 1350℃ to obtain high-temperature flue gas at 1450℃ and calcined coke. 50-70% of the high-temperature flue gas is used for waste heat power generation.

[0070] S2. The remaining high-temperature flue gas is used as a heat source to pyrolyze the second part of petroleum coke at a pyrolysis temperature of 500℃, obtaining pyrolytic coke and pyrolytic gas at about 500℃; at the same time, the high-temperature flue gas, which is used as a heat source, preheats the low-temperature petroleum coke and cools it down to a low-temperature flue gas of 200-250℃.

[0071] S3. The pyrolysis coke is mixed with the first part of petroleum coke and calcined to avoid heat loss caused by intermediate cooling, thereby obtaining calcined coke produced from the first part of petroleum coke and the second part of petroleum coke as raw materials.

[0072] S4. The pyrolysis gas is condensed at 350℃ to obtain tar and residual gas phase;

[0073] S5. Using low-temperature flue gas as a heat source, and calcined coke, coal tar pitch and tar as raw materials, prebaked anodes are prepared by hot pressing.

[0074] S6. Using the condensed pyrolysis gas as a heat source, the prebaked anode after hot pressing is calcined to obtain the prebaked anode finished product.

[0075] In the hot pressing process of S5, the main raw material is calcined coke, and tar and external coal tar pitch are used as forming agents; in the roasting process of S6, the residual gas phase obtained in S4 and external natural gas are used as fuel; the tail gas generated by the hot pressing process and roasting process and the flue gas emitted from the waste heat power generation are purified before being discharged.

[0076] The mass ratio of the first part of petroleum coke in S1 to the second part of petroleum coke in S2 is 1:1.

[0077] By implementing this embodiment, 60-100% of the natural gas used in the existing roasting process can be replaced, resulting in significant energy savings and good economic benefits.

[0078] Example 2

[0079] A petroleum coke resource utilization system for implementing the petroleum coke resource utilization method in Example 1, such as... Figure 1 As shown, it includes a calcination device 1, a pyrolysis device 2, a condensation device 3, and a roasting device 4 connected in sequence; the pyrolysis device 2 and the condensation device 3 are respectively connected to a prebaked anode hot pressing forming device 5.

[0080] The calcination device 1 is a tank-type calcination furnace used to calcine petroleum coke. It uses the input petroleum coke and air as raw materials to carry out calcination, obtain high-temperature flue gas and calcined coke, and transport 30-50% of the high-temperature flue gas to the pyrolysis device 2, and transport 50-70% of the high-temperature flue gas to the waste heat power generation device 6.

[0081] The pyrolysis unit 2 uses the high-temperature flue gas from the calcination unit 1 as a heat source to pyrolyze the petroleum coke, obtaining pyrolysis gas and pyrolysis coke. The pyrolysis unit 2 is close to the calcination unit 1 and can transport the pyrolysis coke back to the calcination unit 1 to participate in calcination to become calcined coke during the period before the pyrolysis coke cools down, thus avoiding heat loss. The pyrolysis gas is used to transport to the condensation unit 3. The high-temperature flue gas becomes low-temperature flue gas after releasing heat and is transported to the prebaked anode hot pressing forming unit 5.

[0082] The condenser 3 is used to condense the pyrolysis gas from the pyrolysis unit 2 to obtain tar. The tar is then transported to the prebaked anode hot pressing forming unit 5. The remaining gas phase after condensing and separating the tar is transported to the roasting unit 4 as gas phase fuel.

[0083] The calcining device 4 is used to calcine the prebaked anode raw material of a set shape prepared in the prebaked anode hot pressing forming device 5. The gaseous fuel and external natural gas supplied by the condensing device 3 are used as raw materials, and the generated tail gas is transported to the flue gas purification device 7.

[0084] The prebaked anode hot pressing molding device 5 is used to prepare prebaked anode raw materials of a set shape. The hot pressing molding process uses low-temperature flue gas from the pyrolysis device 2 as the heat source, calcined coke as the main carbon source, and tar from the condensation device 3 and external coal tar pitch mixed together as the molding agent to realize resource utilization. The generated tail gas is sent to the flue gas purification device 7.

[0085] Waste heat power generation device 6 is a waste heat boiler used to provide electricity for other equipment in the plant, including the prebaked anode hot pressing molding device 5, while producing steam and surplus electricity for external supply, and the exhaust gas is transported to the flue gas purification device 7.

[0086] The flue gas purification device 7 is used to purify the exhaust gas discharged from the calcining device 4, the prebaked anode hot pressing device 5, and the waste heat power generation device 6 before discharging it into the atmospheric environment.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of petroleum coke, characterized in that, Includes the following steps: S1. The first part of the petroleum coke is calcined to obtain high-temperature flue gas at 1000~1450℃ and calcined coke; S2. Using the high-temperature flue gas as a heat source, the second part of petroleum coke is pyrolyzed to obtain pyrolysis coke, pyrolysis gas and low-temperature flue gas at 200~250℃. S3. The pyrolysis coke is mixed with the first part of petroleum coke and then calcined. S4. The pyrolysis gas is condensed to obtain tar; S5. Using the low-temperature flue gas as a heat source, and using the calcined coke, coal tar pitch and tar as raw materials, a prebaked anode is prepared by hot pressing. S6. Using condensed pyrolysis gas as fuel, the prebaked anode raw material after hot pressing is roasted to obtain the prebaked anode product.

2. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, In S1, the calcination temperature is 1000~1350℃.

3. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, In S2, the pyrolysis temperature is 150~700℃, and the high-temperature flue gas is converted into low-temperature flue gas.

4. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, In S3, pyrolysis coke and the first part of petroleum coke are mixed and calcined.

5. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, S6 In the process, the gas phase obtained by condensing the pyrolysis gas in S4 is used as fuel for the prebaking anode roasting process; In S6, other gaseous fuels are mixed in the pre-baking process.

6. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, In S6, the exhaust gas generated during the preparation of the prebaked anode and the flue gas emitted from waste heat power generation are purified before being discharged.

7. The method for resource utilization of petroleum coke as described in claim 1, characterized in that, High-temperature flue gas is used to generate electricity using a set ratio of waste heat.

8. A petroleum coke resource utilization system based on the resource utilization method of any one of claims 1-7, characterized in that, It includes a calcination device, a pyrolysis device, a condensation device, and a roasting device connected in sequence; the pyrolysis device and the condensation device are respectively connected to a prebaked anode hot pressing forming device; The high-temperature flue gas outlet of the calcining device is connected to the pyrolysis device. The pyrolysis gas outlet of the pyrolysis device is connected to the condensation device, and the low-temperature flue gas outlet of the pyrolysis device is connected to the prebaked anode hot pressing device; the residual gas phase outlet of the condensation device is connected to the roasting device, and the condensed tar outlet of the condensation device is connected to the prebaked anode hot pressing device.

9. The petroleum coke resource utilization system as described in claim 8, characterized in that, The roasting device and the prebaked anode hot pressing forming device are respectively connected to the flue gas purification device.

10. The petroleum coke resource utilization system as described in claim 8, characterized in that, The calcination device is connected to the flue gas purification device via a waste heat power generation device.

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