A method for reducing carbon emissions from catalytic conversion of poor-quality heavy oil

Abstract

This invention relates to a method for reducing carbon emissions from the catalytic conversion of low-quality heavy oil. The method includes: contacting the low-quality heavy oil feedstock with a catalytic conversion catalyst in a catalytic conversion reactor to carry out a catalytic conversion reaction; separating the reaction stream to obtain reacted oil and gas and carbon deposits as a precursor catalyst; introducing the precursor catalyst into a first regenerator for a first regeneration under the condition of introducing a first regeneration gas, obtaining primary regenerated flue gas and semi-regenerated catalyst; recovering energy from the primary regenerated flue gas and sending it to a bio-fermentation unit for fermentation; sending the semi-regenerated catalyst into a second regenerator for a second regeneration, obtaining regenerated catalyst and secondary regenerated flue gas; and recycling at least a portion of the secondary regenerated flue gas without heat recovery back to the first regenerator. The method provided by this invention can reduce excess heat and carbon dioxide emissions during the catalytic conversion process.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals, specifically relating to a method for reducing carbon emissions from the catalytic conversion of inferior heavy oil. Background Technology

[0002] As conventional crude oil resources become increasingly depleted, the density, sulfur content, metal content, asphaltene, and carbon residue of crude oil are rising. Catalytic cracking, as a crucial process for refining low-quality heavy oil, plays a vital role in refineries. During the catalytic cracking of low-quality heavy oil, coke is continuously generated and deposited on the active sites of the catalyst surface. This coke is typically regenerated by introducing regeneration gas into the catalyst regenerator. During catalyst regeneration, the combustion of coke produces a large amount of CO2 gas, making the catalytic cracking unit the largest source of CO2 emissions in the refinery. CO2 in catalytic cracking flue gas accounts for 15% to 50% of the total refinery emissions; the average CO2 emission from a catalytic cracking unit processing one ton of feedstock reaches 211.7 kg.

[0003] The flue gas from catalyst regeneration contains carbon monoxide, which often causes tail combustion, leading to localized overheating of the regenerator, accelerated catalyst deactivation, and even potential damage to the regeneration unit due to overheating. To reduce tail combustion, the oxygen content in the flue gas can be reduced; however, this reduces the coking rate and intensity, and also raises concerns about exhaust emissions.

[0004] To recover and utilize carbon monoxide from flue gas, CN102698817A discloses a fluidized bed catalytic converter catalyst pure oxygen regeneration process and hydrogen production method. This significantly improves energy utilization quality and efficiency, reduces energy consumption and pollutant emissions in FCC regeneration systems, and simultaneously produces hydrogen from the generated CO via a water-gas shift reaction. CN101457152A discloses a hydrocarbon-oil conversion method where, during regeneration, the spent catalyst contacts water vapor and oxygen-containing gas in a gasifier to obtain syngas and a semi-regenerated catalyst. This method increases the yield of both carbon monoxide and hydrogen, and carbon monoxide can be converted into hydrogen in subsequent processing, thus achieving a high hydrogen yield.

[0005] The large amount of heat generated during catalyst regeneration can be converted into steam energy using an external heat extraction device, and the energy can be recovered from the high-temperature flue gas. CN105586066A discloses a method for treating catalytic cracking flue gas. This method involves atomizing heavy oil coking feedstock at a temperature of 50-400℃, and then contacting the atomized heavy oil coking feedstock with deoxygenated gas from catalytic cracking regeneration flue gas at a temperature of 490-750℃, thereby recovering energy from the flue gas.

[0006] However, existing technologies for producing hydrogen through incompletely regenerated flue gas, while utilizing coke, still primarily emit carbon as carbon dioxide; and the method of directly contacting the spent catalyst with water vapor to produce syngas would greatly accelerate catalyst deactivation. Summary of the Invention

[0007] The purpose of this invention is to find a way to convert the large amount of coke generated during the catalytic conversion of inferior heavy oil into high-value-added products and reduce carbon emissions.

[0008] To achieve the above objectives, the present invention provides a method for reducing carbon emissions from the catalytic conversion of low-quality heavy oil, the method comprising:

[0009] Inferior heavy oil feedstock is brought into contact with catalytic conversion catalyst in a catalytic conversion reactor to carry out catalytic conversion reaction. The reaction stream is separated to obtain reacted oil and gas and carbon deposits as the catalyst to be generated.

[0010] Under the condition of introducing the first regeneration gas, the catalyst to be regenerated is introduced into the first regenerator for the first regeneration to obtain the first regenerated flue gas and the semi-regenerated catalyst; the first regenerated flue gas is sent to the bio-fermentation unit for fermentation after energy recovery to obtain ethanol, protein feed and fermentation tail gas.

[0011] The semi-regenerated catalyst is fed into a second regenerator for second regeneration to obtain a regenerated agent and regenerated flue gas.

[0012] At least a portion of the second reheated flue gas that has not been heated is recycled back to the first regenerator;

[0013] The first regenerator is selected from one or a combination of two types of bubbling bed and turbulent bed, and the second regenerator is a rapid bed; the regeneration temperature in the first regenerator is 600-900℃, and the bed density is 400-700 kg / m³. 3 .

[0014] Optionally, the residual carbon content in the inferior heavy oil feedstock is 2-20% by weight, and the metal content is 0.1-200 mg / kg; preferably, the inferior heavy oil feedstock is selected from one or more combinations of wax oil, residue oil, hydrogenated residue oil, inferior recycled oil, coal liquefaction oil, oil sands oil, biomass and plastic pyrolysis oil.

[0015] Optionally, the regeneration conditions of the first regenerator include: a regeneration temperature of 680-780℃; an average catalyst residence time of 0.6-20 min, preferably 5-15 min; an apparent gas linear velocity of 0.1-1 m / s; and a bed density of 450-650 kg / m³. 3Preferably, the oxygen content in the first regenerated gas is 20-80% by volume; the CO2 content in the secondary regenerated flue gas is 12-100% by volume; more preferably, the first regenerated gas includes secondary regenerated flue gas and one or more other regenerated gases selected from air, oxygen-enriched air, oxygen, CO2 and fermentation tail gas.

[0016] Optionally, the method further includes: sending the unheated secondary flue gas into a Venturi jet injector to mix and pressurize it with other regenerated gases to obtain a first regenerated gas.

[0017] Optionally, the regeneration conditions of the second regenerator include: a regeneration temperature of 600-750℃, preferably 650-700℃; an average catalyst residence time of 0.6-15 min, preferably 2-10 min; an apparent gas linear velocity of 0.4-3 m / s; and a bed density of 120-350 kg / m³. 3 The preferred value is 180-300 kg / m³. 3 Preferably, the second regeneration gas introduced into the second regenerator is selected from one or a mixture of several of the following: air, oxygen-enriched air, oxygen, secondary flue gas, fermentation tail gas, and CO2.

[0018] Optionally, the CO content in the flue gas is 10-50% by volume.

[0019] Optionally, the method for fermenting the recycled flue gas includes: purifying the recycled flue gas to obtain purified flue gas; feeding the purified flue gas into a fermenter and fermenting the purified flue gas under the action of acetic acid-producing bacteria to obtain fermentation mash and fermentation tail gas; separating the fermentation mash to obtain ethanol and protein feed; preferably, the method further includes: supplementing the bio-fermentation unit with hydrogen; the molar ratio of supplemented hydrogen to CO in the recycled flue gas is (2-30):1.

[0020] Optionally, the acetic acid bacteria are selected from one or a mixture of Clostridium autoethanogenum (DSMZ, Germany) with accession number DSM 19630 and Clostridium autoethanogenum (DSMZ, Germany) with accession number DSM 23693.

[0021] Optionally, the carbon content on the recycled catalyst is not less than 1.2% by weight, preferably 1.5-4% by weight; more preferably, the carbon content on the regenerator is 0-0.05% by weight.

[0022] Optionally, the conditions for the catalytic conversion reaction include: a reaction temperature of 450-700℃, preferably 500-650℃, more preferably 510-630℃; a reaction time of 1-10 seconds, preferably 2-5 seconds; and a catalyst-to-oil ratio of (1-100):1, preferably (5-30):1. The catalytic conversion reactor is selected from one or a combination of two of the following: a riser reactor, a fast bed reactor, and a fluidized bed reactor.

[0023] Through the above technical solution, this invention enables the incomplete combustion of the catalyst that has carbonized after the catalytic conversion of inferior heavy oil feedstock to generate CO, storing some of the energy as chemical energy in the CO, and using the CO-rich secondary flue gas as feedstock for bio-fermentation to produce ethanol and protein feed, thereby reducing excess heat in the catalytic conversion process; at the same time, directly returning the uncooled secondary flue gas to the first regenerator can increase the temperature in the first regenerator during the regeneration process, further reducing energy loss.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a flowchart illustrating a preferred embodiment of the present invention for treating inferior heavy oil catalytic conversion and regeneration flue gas.

[0027] Figure 2 yes Figure 1 A schematic diagram of the structure of a Chinese-made Tully jet injector.

[0028] Figure 3 This is a flowchart of a preferred embodiment of the catalytic cracking-regeneration unit of the present invention.

[0029] Figure 4 This is a flowchart of a preferred embodiment of the bio-fermentation unit provided by the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. First regeneration gas; 2. First regenerator; 3. Semi-regenerated catalyst; 4. Second regenerator; 5. Second regeneration flue gas; 6. Regenerator; 7. Second regeneration gas; 8. First regeneration flue gas; 9. Steam generation unit; 10. Bio-fermentation unit; 11. Ethanol; 12. Protein feed; 13. Fermentation tail gas; 14. Cooled first regeneration flue gas; 15. Venturi jet injector; 16. Other regeneration gases;

[0032] 18. Purification device; 19. Purified flue gas; 20. Fermentation device; 21. Mash; 22. Distillation device; 23. Aqueous ethanol; 24. Ethanol dehydration device; 25. Bacterial residual distillate; 26. Protein separation device; 27. Protein concentrate; 28. Protein drying device;

[0033] 31. Inferior feedstock oil; 32. Catalytic conversion reactor; 33. Settler; 34. Reaction oil and gas; 35. Inclined tube awaiting regeneration; 36. Inclined tube awaiting regeneration; 37. Regeneration inclined tube; 38. Pre-lifting medium. Detailed Implementation

[0034] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0035] In the catalytic conversion of low-quality heavy oil feedstock, the catalyst is more prone to coking. If the coke deposits on the catalyst are completely burned off directly, the heat generated during the burning process is mostly used to generate steam through heat exchange, failing to achieve high-quality utilization of the heat from the coke deposits and also leading to the emission of large amounts of carbon dioxide. To effectively utilize regenerated flue gas and achieve energy conservation and emission reduction, the inventors discovered through research that by controlling the coke combustion conditions during the regeneration process to induce incomplete combustion of the coke deposits, and then using the CO-rich flue gas for bio-fermentation, it is possible to turn waste into treasure and achieve energy conservation and emission reduction. Therefore, this invention is proposed.

[0036] This invention provides a method for reducing carbon emissions from the catalytic conversion of low-quality heavy oil, the method comprising:

[0037] Inferior heavy oil feedstock is brought into contact with catalytic conversion catalyst in a catalytic conversion reactor to carry out catalytic conversion reaction. The reaction stream is separated to obtain reacted oil and gas and carbon deposits as the catalyst to be generated.

[0038] Under the condition of introducing the first regeneration gas, the catalyst to be regenerated is introduced into the first regenerator for the first regeneration to obtain the first regenerated flue gas and the semi-regenerated catalyst; the first regenerated flue gas is sent to the bio-fermentation unit for fermentation after energy recovery to obtain ethanol, protein feed and fermentation tail gas.

[0039] The semi-regenerated catalyst is fed into a second regenerator for second regeneration to obtain a regenerated agent and regenerated flue gas.

[0040] At least a portion of the second reheated flue gas that has not been heated is recycled back to the first regenerator;

[0041] The first regenerator is selected from one or a combination of two of the bubbling bed and the turbulent bed, and the regeneration temperature in the first regenerator is 600-900℃; the second regenerator is a rapid bed.

[0042] This invention utilizes the incomplete combustion of carbonized catalyst from the catalytic conversion of low-quality heavy oil feedstock to generate CO, storing some of the energy as chemical energy in the CO, thus reducing excess heat during the catalytic conversion process. The CO-rich primary flue gas is then used as feedstock for bio-fermentation to produce ethanol and protein feed, increasing the added value of the regenerated flue gas and reducing carbon dioxide emissions. Simultaneously, directly returning the unheated secondary flue gas to the primary regenerator increases the temperature during the regeneration process, further reducing energy loss.

[0043] In this invention, the first regenerator employs a bubbling bed or a turbulent bed, which, while ensuring the fluidization state of the catalyst, increases the concentration of coke and oxygen, extends the catalyst residence time, and promotes more incomplete combustion of coke to generate CO, facilitating its utilization through bio-fermentation. This reduces the amount of CO2 generated from coke combustion in the second regenerator. The second regenerator employs a fast bed, which improves coke burning efficiency, rapidly and completely converts the coke on the semi-regenerated catalyst, effectively restoring the catalyst's activity.

[0044] In some specific embodiments of the present invention, the regeneration temperature in the first regenerator can be 600℃, 650℃, 672℃, 680℃, 791℃, 700℃, 740℃, 780℃, 800℃, 805.3℃, 850℃, or 900℃, or any temperature within the aforementioned range, or a temperature range composed of any two values. Furthermore, the bed density in the first regenerator can be 400 kg / m³. 3 450kg / m 3 500kg / m 3 550kg / m 3 600kg / m 3 650kg / m 3 700kg / m 3 It can be any bed density within the aforementioned range, or any range of values ​​within the aforementioned range.

[0045] This invention involves incomplete regeneration of the spent catalyst in a bubbling or turbulent bed, followed by introduction of the semi-regenerated catalyst into a rapid bed to achieve complete coke conversion. By controlling the regeneration temperature and bed density of the first regenerator, the coke deposits on the spent catalyst can be converted into flue gas with higher CO selectivity. To further improve CO selectivity, the regeneration temperature of the first regeneration is preferably 680–780°C.

[0046] It should be noted that the separated reaction oil and gas can be sent to a subsequent separation system to obtain various catalytic cracking products. After separation by the subsequent separation system, fractions such as dry gas, liquefied petroleum gas, stabilized gasoline and catalytic diesel can be obtained. The separation method can be a conventional technique in the field, and this invention does not limit it, so it will not be described in detail here.

[0047] In some embodiments of the present invention, the carbon content on the spent catalyst is not less than 1.2% by weight, preferably 1.5-4% by weight.

[0048] In the method provided by the present invention, by controlling the bed density of the first regenerator as described above, the coke on the catalytic cracking catalyst can be better converted into carbon monoxide, thereby improving the selectivity of CO in the flue gas and significantly reducing CO2 emissions.

[0049] In some preferred embodiments of the present invention, in order to further improve the selectivity of CO in the regenerated flue gas, the regeneration temperature of the first regenerator is 680-780°C; and the bed density of the first regenerator is 450-650 kg / m³. 3 .

[0050] In some embodiments of the present invention, in order to achieve selectivity in the conversion of coke to CO, the oxygen content in the first regeneration gas in the first regenerator is 20-80% by volume. For example, the oxygen content in the regeneration gas introduced into the first regeneration zone is 20% by volume, 20.21% by volume, 21% by volume, 23.23% by volume, 25% by volume, 25.33% by volume, 30% by volume, 35% by volume, 36.77% by volume, 40% by volume, 50% by volume, 60% by volume, 70% by volume, 80% by volume, or any value within the aforementioned range, or any range of values.

[0051] In some specific embodiments of the present invention, the first regeneration gas includes the secondary flue gas, and also includes one or more other regeneration gases selected from air, oxygen-enriched air, oxygen, CO2, and fermentation tail gas. The secondary flue gas and the other regeneration gases can be mixed and then introduced into the first regenerator, or they can be introduced into the first regenerator separately. When introduced into the first regenerator separately, the gas inlet can be located at the bottom, middle, or other height of the first regenerator.

[0052] In some preferred embodiments of the present invention, the method further includes: feeding the unheated secondary flue gas into a Venturi jet injector to mix and pressurize it with other regenerated gases to obtain a first regenerated gas. The high-temperature, high-pressure secondary flue gas enters the Venturi jet injector, is accelerated through a contraction section, and then rapidly mixes and pressurizes with other low-temperature, low-pressure regenerated gases from the compressor, thus achieving the mixing of gases at different pressures.

[0053] In some preferred embodiments of the present invention, the regeneration conditions of the first regenerator include: an average catalyst residence time of 0.6-20 min, preferably 5-15 min; and a gas apparent linear velocity of 0.1-1 m / s. By controlling the average catalyst residence time and gas apparent linear velocity during the first regeneration process, incomplete combustion of the coke can be achieved.

[0054] In some embodiments of the present invention, the bed density of the second regenerator is 120-350 kg / m³. 3 The preferred value is 180-300 kg / m³. 3 In this invention, by controlling the bed density of the second regenerator, the regeneration effect of the catalyst is ensured while better converting the coke on the spent catalyst of catalytic cracking into carbon monoxide. Specifically, the carbon content on the regenerator is 0-0.05% by weight.

[0055] In some embodiments of the present invention, the regeneration conditions of the second regenerator include: a regeneration temperature of 600-750°C, preferably 650-700°C; an average residence time of the catalyst of 0.6-15 min, preferably 2-10 min; and an apparent gas linear velocity of 0.4-3 m / s.

[0056] In some embodiments of the present invention, the residual carbon content in the inferior heavy oil feedstock is 2-20% by weight, and the metal content is 0.1-200 mg / kg. Inferior heavy oil contains a large amount of impurities such as sulfur, nitrogen, and metals, which makes the catalyst extremely prone to coking during the catalytic conversion process. By selectively converting the coke deposits on the spent catalyst after the catalytic conversion of inferior heavy oil feedstock into CO, CO2 emissions can be significantly reduced, and the energy stored in the coke deposits can be rationally utilized.

[0057] In some embodiments of the present invention, the inferior heavy oil feedstock is selected from one or more combinations of wax oil, residue oil, hydrogenated residue oil, inferior recycled oil, coal liquefaction oil, oil sands oil, biomass and plastic pyrolysis oil.

[0058] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil provided by this invention has wide applicability. The spent catalysts from the carbon deposits produced by the catalytic cracking of the above-mentioned various inferior heavy oil feedstocks can all be converted into flue gas with high CO selectivity through the above-mentioned regeneration process.

[0059] In some specific embodiments of the present invention, the second regeneration gas introduced into the second regenerator is selected from one or a mixture of several of air, oxygen-enriched air, oxygen, secondary flue gas, fermentation tail gas and CO2.

[0060] In this invention, the secondary flue gas is directly recycled back to the first regenerator and / or the second regenerator without heat exchange, which can further reduce energy loss.

[0061] In some embodiments of the present invention, the CO content in the primary flue gas is 10-50% by volume. By controlling the combustion conditions during the regeneration process of the catalyst for the catalytic conversion of inferior heavy oil, CO-rich primary flue gas can be obtained, thereby increasing the CO content in the fermentation feed gas and reducing heat loss.

[0062] In some embodiments of the present invention, the method for fermenting the repeated flue gas includes:

[0063] The flue gas is then purified to obtain purified flue gas.

[0064] The purified flue gas is fed into a fermenter, where it is fermented by acetic acid-producing bacteria to obtain fermentation mash and fermentation tail gas.

[0065] The fermentation mash was separated to obtain ethanol and protein feed;

[0066] The bio-fermentation unit includes a gas purification device, a fermentation device, a distillation device, an ethanol dehydration device, a cell protein separation device, and a protein drying device.

[0067] In some embodiments of the present invention, the microorganism used in the biofermentation process is a strain of *Clostridium autoethanogenum*, deposited at the German Center for Microbiology and Cell Culture Collection (DSMZ) with accession number DSM19630; or the microorganism used is a pure biological isolate of *Clostridium autoethanogenum*, deposited at the German Center for Microbiology and Cell Culture Collection (DSMZ) with accession number DSM23693. These microorganisms have been described in patent applications such as CN103415612A.

[0068] It should be noted that the gas purification device is used to remove trace amounts of dust, trace amounts of oxygen, ammonia nitrogen, sulfides, chlorides, and other impurities from the flue gas, while simultaneously pressurizing it to obtain purified flue gas; the fermentation device is used to ferment the purified flue gas to obtain mash and fermentation tail gas; the fermentation device includes, but is not limited to, stirred reactors, airlift reactors, or other similar bioreactors; the distillation device is used to distill the mash to obtain ethanol, bacterial residual distillate, and sterile residual distillate; the distillation device includes, but is not limited to, crude distillation columns, rectification columns, and combined columns, with the mash entering the crude distillation column, and the top distillate from the crude distillation column entering the rectification column and combined column; the ethanol obtained after distillation contains Some water needs to be removed by an ethanol dehydration device to obtain anhydrous ethanol. The ethanol dehydration device can use molecular sieve dehydration or vaporization permeation membrane dehydration. The anhydrous ethanol obtained by dehydration can be mixed with denaturant to obtain fuel ethanol, or it can be used as a chemical raw material for further synthesis and polymerization. The bacterial protein separation device is used to centrifuge and concentrate the bacterial residual water to obtain centrifuged concentrate and centrifuged clear liquid. The bacterial protein separation device includes, but is not limited to, horizontal screw centrifuge, disc centrifuge, plate and frame filter press and other devices for bacterial separation. The protein drying device is used to dry the centrifuged concentrate to obtain protein feed. The protein drying device includes, but is not limited to, spray drying and drum drying.

[0069] It should be noted that, based on the flue gas composition, the bio-fermentation unit supplements hydrogen to improve the utilization of the recycled flue gas by microorganisms. Preferably, the method further includes: supplementing the bio-fermentation unit with hydrogen; the molar ratio of supplemented hydrogen to CO in the recycled flue gas is (2-30):1.

[0070] It should be noted that, depending on the growth requirements of microorganisms, a small amount of hydrogen sulfide and / or other nutrients required for microbial growth may be supplemented.

[0071] In some embodiments of the present invention, the conditions for the catalytic conversion reaction include: a reaction temperature of 450-700°C, preferably 500-650°C, more preferably 510-630°C; a reaction time of 1-10 seconds, preferably 2-5 seconds; and an agent-to-oil ratio of (1-100):1, preferably (5-30):1.

[0072] In this invention, as a variation of the embodiment, water vapor can also be injected into the catalytic conversion reactor. The water vapor is preferably injected in the form of atomized steam, and the weight ratio of the injected water vapor to the hydrocarbon feedstock can be (0.01-1):1, preferably (0.05-0.25):1.

[0073] The catalytic cracking catalyst used in the catalytic cracking reaction may include 15-65% by weight of natural minerals, 10-30% by weight of inorganic oxides, and 25-75% by weight of zeolite. The zeolite, as the active component, is preferably one or a mixture of more than one of γ-zeolite, mordenite, β-zeolite, and zeolites with an MFI structure (e.g., ZSM series zeolites and / or ZRP zeolite). The natural minerals are selected from one or more of kaolinite, hydrous kaolinite, montmorillonite, diatomite, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite, and rettoite. The inorganic oxides are selected from one or more of silica, alumina, zirconium oxide, titanium dioxide, and amorphous silica-alumina.

[0074] It should be noted that the catalytic conversion reactor can be a conventional catalytic cracking riser reactor, fluidized bed reactor, or a combination thereof, as known to those skilled in the art. For example, a catalytic cracking riser reactor connected in series with a fluidized bed reactor. The riser reactor can be selected from a constant-diameter riser reactor and / or a constant-linear-velocity riser reactor, preferably using a constant-diameter riser. The fluidized bed reactor is located downstream of the riser reactor and connected to the riser reactor outlet. The riser reactor includes, from bottom to top, a pre-rise section and at least one reaction zone. To ensure sufficient reaction of the feedstock and depending on different target product quality requirements, there can be 2-8 reaction zones, preferably 1-3.

[0075] Figure 1 A flowchart illustrating a preferred embodiment of the present invention is shown below. Figure 1 The present invention provides a detailed description of the method for treating the regenerated flue gas from the catalytic cracking of inferior heavy oil.

[0076] The first regeneration gas 1 is introduced into the first regenerator 2 to contact the spent catalyst for the first regeneration, resulting in primary regenerated flue gas 8 and semi-regenerated catalyst 3. The semi-regenerated catalyst 3 enters the second regenerator 4 to contact the second regeneration gas 7 for the second regeneration, resulting in regenerated agent 6 and secondary regenerated flue gas 5. Regenerated agent 6 is recycled back to the catalytic cracking-regeneration unit to continue the reaction.

[0077] The primary flue gas 8 is introduced into the steam generation unit 9 for heat exchange to generate steam, resulting in cooled primary flue gas 14. The cooled primary flue gas 14 is then introduced into the bio-fermentation unit 10 for fermentation, yielding fermentation tail gas 13, ethanol 11, and protein feed 12. Part of the fermentation tail gas 13 is mixed with other regenerated gases 16, compressed, and then sent to a Venturi jet injector 15, where it is mixed with the recirculated secondary flue gas 5 to obtain the first regenerated gas 1.

[0078] Figure 2 yes Figure 1The schematic diagram of the Venturi jet 15 shows that when the fermentation exhaust gas is returned to the first regenerator, the fermentation exhaust gas 13 and other regenerated gases 16 are mixed and compressed, and then enter the Venturi jet 15 to mix with the secondary flue gas 5 to obtain the first regenerated gas 1.

[0079] Figure 3 This is a preferred embodiment of the catalytic cracking-regeneration unit. Inferior feedstock oil 31 is introduced into the catalytic conversion reactor 32, where it contacts a regenerator from the regeneration inclined tube 37, which has been lifted by the pre-lifting medium 38, to undergo a catalytic conversion reaction. The reacted material undergoes gas-solid separation in the settling tank 33, yielding reacted oil and gas 34 and a spent catalyst. The reacted oil and gas 34 is fed into the oil and gas stabilization system, while the spent catalyst enters the first regenerator 2 via the spent catalyst inclined tube 35, where it contacts the first regeneration gas 1 for first regeneration, yielding primary regenerated flue gas 8 and semi-regenerated catalyst 3.

[0080] The semi-regenerated catalyst 3 enters the second regenerator 4 through the waiting inclined tube 36 for second regeneration, and obtains regenerated agent and secondary flue gas 5. Figure 4 This is a preferred embodiment of the bio-fermentation unit in the method provided by the present invention. Cooled primary flue gas 14 is introduced into purification device 18 as the bio-fermentation feed gas for purification to remove impurities. The resulting purified flue gas 19 is introduced into fermentation device 20 and fermented by Clostridium perfringens, yielding fermentation tail gas 13 and mash 21. Mash 21 is sent to distillation device 22 for separation, yielding aqueous ethanol 23 and bacterial residue 24. Aqueous ethanol 23 is sent to ethanol dehydration device 24 for dehydration, yielding ethanol 11. Bacterial residue 24 is sent to protein separation device 26 for separation, yielding concentrated protein 27. Concentrated protein 27 is then dried in protein drying device 28 to obtain protein feed 12.

[0081] The method provided by this invention can not only reduce carbon dioxide emissions from catalytic devices, but also produce ethanol and protein feed from flue gas through bio-fermentation, thereby achieving full utilization of resources, reducing pollution, and improving the economic and social benefits of the petrochemical industry.

[0082] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0083] In the following examples, the first regenerator is a turbulent bed, and the second regenerator is a rapid bed. The microorganism used in the biofermentation unit, Clostridium autoethanogenum, DSM 19630, was purchased from the German Culture Collection (DSMZ, Germany).

[0084] The inferior heavy oil feedstock used in the examples and comparative examples was hydrotreated residue oil, the properties of which are shown in Table 1.

[0085] Table 1

[0086]

[0087]

[0088] The catalytic conversion catalysts used in the examples and comparative examples are commercially available under the brand name CDOS, manufactured by Changling Branch of Sinopec Catalyst Co., Ltd., and their properties are shown in Table 2. Before use, they were hydrothermally aged at 800°C in 100% steam for 17 hours.

[0089] Table 2

[0090] Catalytic conversion catalyst CDOS Chemical composition, weight % <![CDATA[SiO2]]> 38.2 <![CDATA[Al2O3]]> 54.5 Physical properties <![CDATA[BET specific surface area, m 2 / g]]> 108 <![CDATA[Substrate area, m 2 / g]]> 60 <![CDATA[Micropore area, m 2 / g]]> 48 <![CDATA[Total pore volume, cm 3 / g]]> 0.181 <![CDATA[Micropore volume, cm 3 / g]]> 0.022 Activity (17h), % 54

[0091] Example 1

[0092] This embodiment illustrates the method of reducing carbon emissions from the catalytic conversion of inferior heavy oil according to the present invention, including:

[0093] use Figures 1 to 4 The process shown was tested. Inferior heavy oil feedstock (properties shown in Table 1) was fed into a catalytic conversion reactor and contacted with a regenerator for catalytic conversion. The reacted material underwent gas-solid separation in a settling tank, yielding reacted oil gas and a spent catalyst. The conditions in the catalytic conversion reactor included: a reaction temperature of 620℃, a catalyst-to-oil ratio of 10, and a reaction time of 3 seconds; the carbon content on the spent catalyst was 1.83% by weight.

[0094] The separated catalyst enters the first regenerator through the regenerated inclined tube. In the first regenerator, it comes into contact with the first regeneration gas for the first regeneration, resulting in primary regeneration flue gas and semi-regenerated catalyst. The primary regeneration flue gas is sent to the steam generation unit for heat exchange, cooling and impurity removal, and then sent to the biological fermentation unit for fermentation, resulting in fermentation tail gas, ethanol and protein feed.

[0095] The semi-regenerated catalyst enters the second regenerator and comes into contact with the second regenerated gas for a second regeneration, resulting in a regenerator and a second regenerated flue gas. The regenerator is then circulated back to the catalytic conversion reactor via pipeline. At least a portion of the unheated second regenerated flue gas is sent to a Venturi jet injector and mixed with other regenerated gases from the compressor before being circulated back to the first regenerator.

[0096] The conditions for the first regeneration include: a regeneration temperature of 700℃; an apparent gas linear velocity of 0.8 m / s; and a bed density of 450 kg / m³. 3The average residence time of the catalyst is 8 min; other regeneration gases in the first regeneration gas include O2 and CO2, and the first regeneration gas includes 74.67 vol% CO2 and 25.33 vol% O2; the temperature in the fermenter is 30℃ and the pressure is 0.5 MPa; the cell concentration is 9.05 g / L and the first regeneration flue gas feed rate is 5.5 SCFM.

[0097] The conditions for the second regeneration include: a regeneration temperature of 680℃; an apparent gas linear velocity of 2 m / s; and a bed density of 200 kg / m³. 3 The average residence time of the catalyst is 3 min; the second regeneration gas is a mixture of O2 and CO2, including 79% CO2 and 21% O2 by volume.

[0098] The reaction conditions and results are shown in Table 3.

[0099] Example 2

[0100] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that the regeneration temperature of the first regenerator is 740°C.

[0101] The reaction conditions and results are shown in Table 3.

[0102] Example 3

[0103] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that the regeneration temperature of the first regenerator is 672°C.

[0104] The reaction conditions and results are shown in Table 3.

[0105] Example 4

[0106] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that the regeneration temperature of the first regenerator is 791℃ and the bed density is 400 kg / m³. 3 .

[0107] The reaction conditions and results are shown in Table 3.

[0108] Comparative Example 1

[0109] The catalytic conversion method for inferior heavy oil in this comparative example follows the appendix. Figure 3 The process was tested, meaning that the regenerated flue gas was not fed into the bio-fermentation unit for fermentation; the first regeneration gas was air, and the conditions for the first regeneration included: a regeneration temperature of 650℃; an apparent gas linear velocity of 2 m / s; and a bed density of 200 kg / m³. 3 The average residence time of the catalyst is 8 minutes.

[0110] The second regeneration gas is air, and the conditions for the second regeneration include: a regeneration temperature of 700℃; an apparent gas linear velocity of 2 m / s; and a bed density of 200 kg / m³. 3 The average residence time of the catalyst is 3 minutes.

[0111] The reaction conditions and results are shown in Table 3.

[0112] Comparative Example 2

[0113] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this comparative example is basically similar to that in Example 1, except that: the first regeneration gas contains 74.67% by volume CO2 and 25.33% by volume O2; the regeneration conditions for the first regeneration include: a regeneration temperature of 700°C; a gas apparent linear velocity of 2 m / s; and a bed density of 200 kg / m³. 3 The average residence time of the catalyst is 8 minutes.

[0114] The second regeneration gas comprises 79% by volume CO2 and 21% by volume O2; the regeneration conditions for the second regeneration include: a regeneration temperature of 680℃; an apparent gas linear velocity of 8 m / s; and a bed density of 80 kg / m³. 3 The average residence time of the catalyst is 1 min.

[0115] The reaction conditions and results are shown in Table 3.

[0116] Table 3

[0117]

[0118]

[0119] Example 5

[0120] The method for reducing carbon emissions from the catalytic conversion of low-quality heavy oil in this embodiment is basically similar to that in Example 1, except that the first regenerated gas contains 63.23% by volume CO2 and 36.77% by volume O2. The reaction conditions and results are shown in Table 4.

[0121] Example 6

[0122] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that: O2 and fermentation tail gas are mixed and compressed and then fed into a Venturi jet injector. In the Venturi jet injector, it is mixed with unheated secondary flue gas to obtain the first regenerated gas, which includes 74.11 vol% CO2, 23.23 vol% O2 and 2.66 vol% CO.

[0123] The reaction conditions and results are shown in Table 4.

[0124] Example 7

[0125] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that the first regeneration gas is a mixture of O2 and secondary flue gas, including 79.79% by volume of CO2 and 20.21% by volume of O2.

[0126] The reaction conditions and results are shown in Table 4.

[0127] Example 8

[0128] The method for reducing carbon emissions from the catalytic conversion of inferior heavy oil in this embodiment is basically similar to that in Example 1, except that: the first regeneration gas is a mixture of O2, secondary flue gas and air, including 5.21 vol% CO2, 25.33 vol% O2 and 69.46 vol% N2; the second regeneration gas is air.

[0129] The reaction conditions and results are shown in Table 4.

[0130] Table 4

[0131]

[0132]

[0133] As can be seen from the results in Tables 3 and 4, the method of the present invention can reduce carbon dioxide emissions, increase the proportion of CO in the regenerated flue gas, and increase the added value of CO in the regenerated flue gas of inferior feedstock oil catalyst.

[0134] In existing technologies, air is directly used to regenerate the spent catalyst by burning coke. The coke deposits on the spent catalyst are mainly converted into carbon dioxide, and the energy stored in the coke cannot be effectively utilized, further exacerbating the problem of exhaust gas treatment. Compared to Comparative Example 2, the method provided by this invention achieves incomplete regeneration by contacting the first regeneration gas with a high-density catalyst in the first regenerator, thereby improving the selectivity of CO in the first regeneration flue gas and further reducing carbon dioxide emissions. In Examples 1-4 of this application, by changing the regeneration conditions in the first regeneration zone, the selectivity of CO in the second flue gas can be improved, thereby increasing the amount of ethanol in the bio-fermentation products and reducing CO2 emissions.

[0135] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0136] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0137] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for reducing carbon emissions from the catalytic conversion of low-quality heavy oil, characterized in that, The method includes: Inferior heavy oil feedstock is brought into contact with catalytic conversion catalyst in a catalytic conversion reactor to carry out catalytic conversion reaction. The reaction stream is separated to obtain reacted oil and gas and carbon deposits to be generated catalyst. Under the condition of introducing the first regeneration gas, the catalyst to be regenerated is introduced into the first regenerator for the first regeneration to obtain the first regenerated flue gas and the semi-regenerated catalyst; the first regenerated flue gas is sent to the bio-fermentation unit for fermentation after energy recovery to obtain ethanol, protein feed and fermentation tail gas. The semi-regenerated catalyst is fed into a second regenerator for second regeneration to obtain a regenerated agent and regenerated flue gas. At least a portion of the second reheated flue gas that has not been heated is recycled back to the first regenerator; The first regenerator is selected from one or a combination of two types of bubbling bed and turbulent bed, and the second regenerator is a rapid bed; the regeneration temperature in the first regenerator is 600-900℃, and the bed density is 400-700 kg / m³. 3 .

2. The method according to claim 1, wherein, The residual carbon content in the inferior heavy oil feedstock is 2-20% by weight, and the metal content is 0.1-200 mg / kg; Preferably, the inferior heavy oil feedstock is selected from one or more combinations of wax oil, residue oil, hydrogenated residue oil, inferior recycled oil, coal liquefaction oil, oil sands oil, biomass and plastic pyrolysis oil.

3. The method according to claim 1, wherein, The regeneration conditions of the first regenerator include: a regeneration temperature of 680-780℃; an average catalyst residence time of 0.6-20 min, preferably 5-15 min; an apparent gas linear velocity of 0.1-1 m / s; and a bed density of 450-650 kg / m³. 3 ; Preferably, the oxygen content in the first regenerated gas is 20-80% by volume; and the CO2 content in the second regenerated flue gas is 12-100% by volume. More preferably, the first regenerated gas includes secondary flue gas and other regenerated gases selected from one or more of air, oxygen-enriched air, oxygen, CO2 and fermentation tail gas.

4. The method according to claim 1 or 3, wherein, The method further includes: sending the unheated secondary flue gas into a Venturi jet injector to mix and pressurize it with other regenerated gases to obtain a first regenerated gas.

5. The method according to claim 1, wherein, The regeneration conditions for the second regenerator include: a regeneration temperature of 600-750℃, preferably 650-700℃; an average catalyst residence time of 0.6-15 min, preferably 2-10 min; an apparent gas linear velocity of 0.4-3 m / s; and a bed density of 120-350 kg / m³. 3 The preferred value is 180-300 kg / m³. 3 ; Preferably, the second regeneration gas introduced into the second regenerator is selected from one or a mixture of several of air, oxygen-enriched air, oxygen, secondary flue gas, fermentation tail gas, and CO2.

6. The method according to claim 1, wherein, The CO content in the flue gas is 10-50% by volume.

7. The method according to claim 1, wherein, The method for fermenting the re-fermented flue gas includes: The flue gas is then purified to obtain purified flue gas. The purified flue gas is fed into a fermenter, where it is fermented by acetic acid-producing bacteria to obtain fermentation mash and fermentation tail gas. The fermentation mash was separated to obtain ethanol and protein feed; Preferably, the method further includes: supplementing the bio-fermentation unit with hydrogen; the molar ratio of the supplemented hydrogen to CO in the primary flue gas is (2-30):

1.

8. The method according to claim 7, wherein, The acetic acid bacteria are selected from one or a mixture of Clostridium autoethanogenum (DSMZ, Germany) with accession number DSM 19630 and Clostridium autoethanogenum (DSMZ, Germany) with accession number DSM 23693.

9. The method according to claim 1, wherein, The carbon content on the catalyst to be generated is not less than 1.2% by weight, preferably 1.5-4% by weight; Preferably, the carbon content of the regenerator is 0-0.05% by weight.

10. The method according to claim 1, wherein, The conditions for the catalytic conversion reaction include: a reaction temperature of 450-700℃, preferably 500-650℃, more preferably 510-630℃; a reaction time of 1-10 seconds, preferably 2-5 seconds; and an agent-to-oil ratio of (1-100):1, preferably (5-30):

1. The catalytic conversion reactor is selected from one or a combination of two of the following: riser reactor, fast bed reactor, and fluidized bed reactor.

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