Catalytic cracking flue gas utilization method

Abstract

The invention relates to a catalytic cracking flue gas utilization method, which comprises: contacting a hydrocarbon oil raw material with a catalytic conversion catalyst in a catalytic conversion reactor, carrying out a catalytic conversion reaction, separating the material flow after the reaction, feeding the obtained spent catalyst into a first regenerator, and carrying out first regeneration, first flue gas and a semi-regenerated catalyst are obtained; feeding part or all of the first flue gas into a biological fermentation unit to ferment the first flue gas to obtain ethanol, a protein feed and fermentation tail gas; wherein the first regenerator is selected from one or a combination of several of a bubbling bed, a turbulent flow bed and a fast bed; the regeneration temperature of the first regeneration is 600-900 DEG C; and the second regenerator is selected from one or a combination of several of a bubbling bed, a turbulent flow bed and a fast bed. The method provided by the invention can reduce heat excess in the regeneration process of the spent catalyst, and also can greatly reduce CO2 emission.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals, specifically relating to a method for utilizing catalytic cracking flue gas. Background Technology

[0002] Catalytic cracking of petroleum feedstocks is an important petroleum refining process. A catalytic cracking unit mainly consists of a catalytic conversion reactor and a catalyst regenerator. Generally, the coked catalyst is 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 refinery's total emissions; the average CO2 emission from a catalytic cracking unit processing one ton of feedstock reaches 211.7 kg.

[0003] Catalyst regeneration generates a large amount of heat, leading to excess heat that necessitates external heat recovery devices to convert this heat into steam and recover energy from the high-temperature flue gas. However, these methods represent low-quality energy utilization. Furthermore, the regenerated flue gas contains carbon monoxide, which often causes tail combustion, leading to localized overheating of the regenerator, accelerated catalyst deactivation, and even damage to the regeneration equipment due to overheating. Controlling the oxygen content in the flue gas to reduce tail combustion would decrease the coking rate and intensity, while still raising concerns about emissions. Refineries typically use carbon monoxide combustion aids or flue gas carbon monoxide boilers to reduce carbon monoxide in the flue gas and recover energy.

[0004] CN1400159A discloses a method for producing hydrogen using catalytic cracking regenerated flue gas. This method allows for the rational utilization of CO in the regenerated flue gas and alleviates the problem of excess heat in FCC units. However, the CO content obtained by this method is around 14 vol%, while the nitrogen content is above 70 vol%.

[0005] CN102698817A discloses a pure oxygen regeneration process and hydrogen production method for a fluidized catalytic conversion catalyst, which can significantly improve the quality and efficiency of energy utilization, reduce the energy consumption and pollutant emissions of the FCC regeneration system, and simultaneously produce hydrogen from the generated CO through a water-gas shift reaction.

[0006] CN101457152A discloses a method for hydrocarbon-oil conversion. During the regeneration process, the spent catalyst is contacted with water vapor and oxygen-containing gas in a gasifier to obtain syngas and a semi-regenerated catalyst. This method can increase the yield of carbon monoxide and hydrogen, and carbon monoxide can also be converted into hydrogen in subsequent processing, thereby achieving a high hydrogen yield.

[0007] While existing technologies for producing hydrogen through incompletely regenerated flue gas can utilize coke, carbon emissions are still primarily in the form of carbon dioxide; and methods for producing syngas by directly contacting the spent catalyst with water vapor accelerate catalyst deactivation. Summary of the Invention

[0008] The purpose of this invention is to further improve the selectivity of CO in the regenerated flue gas of the carbon deposit catalyst and to carry out bio-fermentation of the regenerated flue gas to reduce CO2 emissions.

[0009] To achieve the above objectives, the present invention provides a method for utilizing catalytic cracking flue gas, the method comprising: The hydrocarbon feedstock is brought into contact with the catalytic conversion catalyst in a catalytic conversion reactor to carry out a catalytic conversion reaction. The reaction stream is then separated to obtain the reacted oil and gas and the unused catalyst with carbon deposits. The catalyst to be generated is fed into the first regenerator for first regeneration to obtain first flue gas and semi-regenerated catalyst; Part or all of the first flue gas is fed into a biological fermentation unit to ferment the first flue gas and obtain ethanol, protein feed and fermentation tail gas. The semi-regenerated catalyst is fed into a second regenerator for a second regeneration to obtain a regenerator and a second flue gas; wherein, the first regenerator is selected from one or a combination of several of the bubble bed, turbulent bed and fast bed; the regeneration temperature of the first regeneration is 600-900 ℃; the second regenerator is selected from one or a combination of several of the bubble bed, turbulent bed and fast bed.

[0010] Optionally, the regeneration temperature of the first regeneration is 680-780 °C; the conditions for the first regeneration include: 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 400-700 kg / m³. 3 Preferably 450-600 kg / m 3 .

[0011] Optionally, the conditions for the second regeneration include: a regeneration temperature of 600-750 °C, preferably 650-700 °C; 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 120-450 kg / m³. 3 Preferably 180-300 kg / m 3 .

[0012] Optionally, the first regeneration gas introduced into the first regenerator is selected from one or a mixture of several of air, oxygen-enriched air, oxygen, CO2, second flue gas, and fermentation tail gas; and / or the second regeneration gas introduced into the second regenerator is selected from one or a mixture of several of air, oxygen-enriched air, oxygen, first flue gas, fermentation tail gas, and CO2.

[0013] Optionally, the oxygen content in the first regenerated gas is 20-80% by volume.

[0014] Optionally, the CO content in the first flue gas is 10-50% by volume; the molar ratio of CO to CO2 in the first flue gas is 0.2-1.5; optionally, the method further includes: recovering energy from the first flue gas to obtain fermentation raw material gas, and sending the fermentation raw material gas into the bio-fermentation unit.

[0015] Optionally, the method for fermenting the first flue gas includes: purifying the first 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.

[0016] Optionally, the acetic acid bacteria are selected from Clostridium difficile, which produces its own ethanol, with the microbial accession number DSM 19630. Clostridium autoethanogenum Clostridium ethanoliferum (DSMZ, Germany) and microbial accession number DSM 23693 (DSM 23693) Clostridium autoethanogenum A mixture of one or two of the following (DSMZ, Germany).

[0017] Optionally, the carbon content of the regenerator is 0-0.05% by weight.

[0018] Optionally, the conditions for the catalytic conversion reaction include: a reaction temperature of 450-700 ℃, a time of 1-10 seconds, and a catalyst-to-oil ratio of (1-100):1; the catalytic conversion reactor is selected from one or a combination of riser reactors and fluidized bed reactors; optionally, the hydrocarbon feedstock is selected from petroleum hydrocarbons and / or mineral oils, wherein the petroleum hydrocarbons are selected from one or a combination of gasoline, diesel, vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, hydrotreated heavy oil, hydrotreated tail oil, extracted oil, and inferior recycled oil; and the mineral oil is selected from one or a combination of coal liquefaction oil, oil sands oil, and shale oil.

[0019] Through the above technical solution, the present invention obtains a first flue gas with high CO selectivity by sending the carbonized spent catalyst into the first regenerator for incomplete combustion. This allows some energy to be stored in CO as chemical energy, reducing excess heat during the spent catalyst regeneration process and significantly reducing CO2 emissions. At the same time, using the first flue gas for bio-fermentation to produce ethanol and protein feed can further improve the utilization value of the flue gas.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] 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: Figure 1 This is a flowchart illustrating a method provided in one embodiment of the present invention.

[0022] Figure 2 This is a schematic flowchart of a catalytic cracking-regeneration unit according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic flowchart of a bio-fermentation unit provided in one embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures: 1. Pipeline; 2. First Regenerator; 3. Semi-regenerating Pipeline; 4. Second Regenerator; 5. Pipeline; 6. Pipeline; 7. Pipeline; 8. Pipeline; 9-1, 9-2 Energy Recovery Units; 10. Bio-fermentation Unit; 11. Pipeline; 12. Pipeline; 13. Pipeline; 14. Pipeline; 15. Purification Device; 16. Pipeline; 17. Fermentation Device; 18. Pipeline; 19. Distillation Device; 20. Pipeline; 21. Ethanol Dehydration Device; 22. Pipeline; 23. Protein Separation Device; 24. Pipeline; 25. Protein Drying Device; 26. Pipeline; 31. Pipeline; 32. Catalytic conversion reactor; 33. Settler; 34. Pipeline; 35. Preparing inclined tube; 36. Slide valve; 37. Regenerating inclined tube; 38. Pipeline. Detailed Implementation

[0025] 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.

[0026] This invention provides a method for utilizing catalytic cracking flue gas, the method comprising: The hydrocarbon feedstock is brought into contact with the catalytic conversion catalyst in a catalytic conversion reactor to carry out a catalytic conversion reaction. The reaction stream is then separated to obtain the reacted oil and gas and the unused catalyst with carbon deposits. The catalyst to be generated is fed into the first regenerator for first regeneration to obtain first flue gas and semi-regenerated catalyst; Part or all of the first flue gas is fed into a biological fermentation unit to ferment the first flue gas and 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 second flue gas. The first regenerator is selected from one or a combination of bubbling bed, turbulent bed and fast bed; the regeneration temperature of the first regenerator is 600-900 ℃; the second regenerator is selected from one or a combination of bubbling bed, turbulent bed and fast bed.

[0027] This invention obtains a first flue gas with high CO selectivity by feeding the carbonized spent catalyst into a first regenerator for incomplete combustion. This allows some energy to be stored in CO as chemical energy, reducing excess heat during the spent catalyst regeneration process and significantly reducing CO2 emissions. At the same time, using the first flue gas for bio-fermentation to produce ethanol and protein feed can further improve the utilization value of the flue gas.

[0028] In some embodiments of the present invention, by feeding the carbonized spent catalyst into a first regenerator and introducing a first regeneration gas, the carbon deposits on the spent catalyst are selectively converted into the first flue gas. In order to allow the carbon deposits on the spent catalyst to come into contact with the first regeneration gas for incomplete combustion to obtain a semi-regenerated catalyst, the first regenerator may be selected from one or a combination of several of bubbling bed, turbulent bed and fast bed.

[0029] In a preferred embodiment of the present invention, the first regenerator is a bubble bed. By performing the first regeneration of the catalyst in the bubble bed, the concentration of coke and oxygen can be increased while ensuring the fluidization state of the catalyst, the average residence time of the catalyst can be increased, and more coke can be incompletely burned to generate CO, which is convenient for bio-fermentation utilization, thereby reducing the amount of CO2 generated by the combustion of coke in the second regenerator.

[0030] In the first regenerator, the contact mode between the catalyst to be generated and the first regeneration gas can be either countercurrent or cocurrent.

[0031] In a preferred embodiment of the present invention, the second regenerator is a turbulent bed and / or a fast bed, which can improve the coke burning efficiency, thereby quickly and completely converting the coke on the semi-regenerated catalyst and rapidly and efficiently restoring the activity of the catalytic conversion catalyst.

[0032] In some embodiments of the present invention, in the above-mentioned regenerator, the regeneration temperature in the first regenerator can be 600-900 °C, so that the carbon deposits on the catalyst to be regenerated can be converted into flue gas with higher CO selectivity; in order to further improve CO selectivity, the regeneration temperature of the first regeneration is preferably 680-780 °C.

[0033] In some embodiments of the present invention, the conditions for the first regeneration include: 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 400-700 kg / m³. 3 Preferably 450-600 kg / m 3 By controlling the reaction conditions of the first regenerator, the coke on the spent catalyst can be better converted into carbon monoxide, enabling the coke to be converted into flue gas with higher CO selectivity, significantly reducing CO2 emissions, while ensuring the regeneration effect of the catalyst.

[0034] In some embodiments of the present invention, the first regeneration gas introduced into the first regenerator is selected from one or a mixture of several of air, oxygen-enriched air, oxygen, CO2, second flue gas, and fermentation tail gas. Specifically, the second flue gas can be partially recycled back to the first regenerator after energy recovery. By recycling part of the second flue gas for the coke gasification reaction in the first regenerator, it is beneficial to improve CO yield and further reduce CO2 emissions.

[0035] The components of the first regenerated gas can be mixed before entering the first regenerator, or they can enter the first regenerator separately. When the components of the first regenerated gas enter the first regenerator separately, the gas inlet can be located at the bottom, middle, or other locations of the first regenerator.

[0036] In some embodiments of the present invention, the oxygen content in the first regenerated gas is 20-80% by volume. This is to increase the CO yield in the first flue gas.

[0037] In some embodiments of the present invention, the CO content in the first flue gas is 10-50% by volume.

[0038] The obtained semi-regenerated catalyst enters the second regenerator and comes into contact with the second regenerated gas for second regeneration. In the second regenerator, the contact between the semi-regenerated catalyst and the second regenerated gas can be countercurrent or cocurrent. The second flue gas obtained from the second regenerator can be partially recycled back to the first or second regenerator, or discharged from the device after energy recovery.

[0039] In some embodiments of the present invention, the conditions for the second regeneration include: a regeneration temperature of 600-750 °C, preferably 650-700 °C; 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 120-450 kg / m³. 3 Preferably 180-300 kg / m 3 By controlling the above reaction conditions, the coke on the semi-regenerated catalyst can be completely converted, thus restoring the catalyst activity. For example, when the regeneration temperature and / or bed density of the second regeneration are too low, the coke regeneration effect of the semi-regenerated catalyst is poor, which may result in a high carbon content on the regenerator.

[0040] In some 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, first flue gas, fermentation tail gas, and CO2. Specifically, in some embodiments of the present invention, the coke on the catalyst to be recycled is selectively converted into CO, and the molar ratio of CO to CO2 in the first flue gas is 0.2-1.5.

[0041] In some embodiments of the present invention, the method further includes: recovering energy from the first flue gas to obtain fermentation raw material gas, and sending the fermentation raw material gas into the bio-fermentation unit.

[0042] In this invention, the bio-fermentation unit includes a gas purification device, a fermentation device, a distillation device, an ethanol dehydration device, a microbial protein separation device, and a protein drying device. The gas purification device removes trace amounts of dust, trace amounts of oxygen, ammonia nitrogen, sulfides, chlorides, and other impurities from the first flue gas, while simultaneously pressurizing it to obtain purified flue gas. The fermentation device ferments the purified flue gas to obtain mash and fermentation tail gas.

[0043] In some embodiments of the present invention, the method for fermenting the first flue gas includes: The first flue gas is 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.

[0044] In some embodiments of the present invention, the microorganism used in the fermentation process is an acetic acid bacterium, which can be a self-producing ethanol-bearing Clostridium difficile with the microbial preservation number DSM 19630. Clostridium autoethanogenum), which is deposited at the German Center for Microbiology and Cell Culture Collection (DSMZ), and can also be the self-producing Clostridium ethanoliferous bacteria deposited at the German Center for Microbiology and Cell Culture Collection (DSMZ) with accession number DSM 23693 ( Clostridium autoethanogenum ) Pure biological isolates. Alternatively, the aforementioned two acetic acid bacteria can be used for fermentation to produce ethanol and protein feed.

[0045] The fermenter can be a stirred reactor, an airlift reactor, or other similar bioreactor. Fermentation conditions include: temperature 29-37 ℃; pressure 0.5-0.6 MPa.

[0046] The fermentation mash can be separated by distillation to obtain ethanol, a bacterial residue, and a sterile residue. The distillation apparatus includes, but is not limited to, a crude distillation column, a rectification column, and a combined column. The mash enters the crude distillation column, and the top distillate from the crude distillation column enters the rectification column and the combined column.

[0047] The ethanol obtained through distillation contains some water, which 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 a denaturing agent to obtain fuel ethanol, or it can be used as a chemical raw material for further synthesis and polymerization.

[0048] The bacterial protein separation device is used to centrifuge and concentrate the bacterial residue to obtain a concentrated centrifuged liquid and a clarified centrifuged liquid. The bacterial protein separation device includes, but is not limited to, devices for bacterial separation such as horizontal screw centrifuges, disc centrifuges, and plate and frame filter presses; the protein drying device is used to dry the concentrated centrifuged liquid to obtain protein feed. The protein drying device includes, but is not limited to, spray drying and drum drying.

[0049] 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.

[0050] In some embodiments of the present invention, the carbon content of the regenerator is 0-0.05% by weight, and the regenerator can be entirely recycled into the catalytic conversion reactor. At least a portion of the catalytic conversion catalyst used in the catalytic cracking reaction is the regenerator, preferably all of it.

[0051] The regenerator is preferably degassed before being returned to the catalytic conversion reactor for recycling.

[0052] The regenerator may be equipped with an internal or external heat exchanger to facilitate control of the regeneration temperature. The type, connection, and operation of the heat exchanger are well known to those skilled in the art.

[0053] The energy recovery process includes using a flue gas turbine to recover flue gas pressure energy and generate steam.

[0054] In one embodiment of the present invention, the hydrocarbon feedstock is selected from petroleum hydrocarbons and / or mineral oils. The petroleum hydrocarbons may be selected from one or more combinations of gasoline, diesel, vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, hydrotreated heavy oil, hydrotreated tail oil, extracted oil, and low-quality recycled oil. The mineral oils may be selected from one or more combinations of coal liquefaction oil, oil sands oil, and shale oil.

[0055] It should be noted that the method of the present invention has a wide range of applicability. The spent catalysts produced by the catalytic cracking of the above-mentioned various hydrocarbon feedstocks can be converted into flue gas with high CO selectivity through the above-mentioned regeneration process.

[0056] In some embodiments of the present invention, the catalytic conversion 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.

[0057] The zeolite, as the active component, is preferably one or a mixture of more than one of the following: Y zeolite, mordenite, β zeolite, and zeolite with MFI structure (e.g., ZSM series zeolite and / or ZRP zeolite); the natural mineral is selected from one or more of kaolinite, hydrous kaolinite, montmorillonite, diatomite, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite, and rettoite; and the inorganic oxide is selected from one or more of silicon dioxide, aluminum oxide, zirconium oxide, titanium dioxide, and amorphous aluminum silicate.

[0058] 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 (the weight ratio of the catalytic conversion catalyst to the hydrocarbon feedstock) of 1-100:1, preferably 5-30:1.

[0059] In some embodiments of the present invention, the catalytic conversion reactor may be a conventional catalytic cracking riser reactor, a fluidized bed reactor, or a combination thereof, as known to those skilled in the art. For example, it may be a catalytic cracking riser reactor connected in series with a fluidized bed reactor.

[0060] The riser reactor can be selected from equal-diameter riser reactors and / or equal-linear-velocity riser reactors, with equal-diameter risers being preferred.

[0061] The fluidized bed reactor is located downstream of the riser reactor and connected to the outlet of the riser reactor. The riser reactor includes a pre-rise section and at least one reaction zone from bottom to top. In order to ensure that the feed oil can react fully and according to different product quality requirements, there can be 2-8 reaction zones, preferably 1-3.

[0062] In this invention, water vapor can also be injected into the catalytic conversion reactor. The water vapor is preferably injected in the form of atomized steam. The weight ratio of the injected water vapor to the hydrocarbon feedstock can be 0.01-1:1, preferably 0.05-0.25:1.

[0063] In this invention, the separated reaction oil and gas can be fed into a subsequent separation system to obtain various catalytic cracking products. The reaction oil and gas, after further separation by the subsequent system, yields fractions such as dry gas, liquefied petroleum gas (LPG), stabilized gasoline, and catalytic diesel. The separation method can be any conventional technique in the art, and this invention does not limit this; therefore, it will not be described in detail here. The catalyst to be generated originates from the catalytic conversion reactor of the hydrocarbon feedstock.

[0064] The method of the present invention can be implemented based on a system for the bio-utilization of catalytic cracking flue gas, which includes a catalytic cracking reaction-regeneration unit, an energy recovery unit, and a bio-fermentation unit.

[0065] Figure 1 A preferred embodiment of the present invention is illustrated schematically. The following description, in conjunction with... Figure 1 The method for utilizing catalytic cracking flue gas provided by this invention will be described in detail.

[0066] The first regeneration gas from pipeline 1 is introduced into the first regenerator 2 to contact the catalyst to be regenerated for the first regeneration, resulting in the first flue gas and the semi-regenerated catalyst. The semi-regenerated catalyst is sent to the second regenerator 4 through the semi-regeneration pipeline 3 to contact the second regeneration gas from pipeline 7 for the second regeneration, resulting in the regenerator and the second flue gas.

[0067] The first flue gas obtained in the first regenerator 2 is introduced into the energy recovery unit 9-1 via pipeline 8 for energy recovery, resulting in fermentation feed gas. The fermentation feed gas is then introduced into the biological fermentation unit 10 via pipeline 14 for fermentation, yielding fermentation tail gas, ethanol, and protein feed. Part of the fermentation tail gas is recycled back to the first regenerator 2 via pipeline 13; ethanol and protein feed are sent out of the system via pipelines 11 and 12, respectively.

[0068] The second flue gas is introduced into the energy recovery unit 9-2 via pipeline 5 for energy recovery. The recovered second flue gas is then partially recycled back to the first regenerator via pipeline 26.

[0069] Figure 2This is a preferred embodiment of the catalytic cracking-regeneration unit. Hydrocarbon oil feedstock is introduced into the catalytic conversion reactor 32 via pipeline 31. The feedstock contacts the regenerator from the regeneration inclined tube 37, which is pre-lifted via pipeline 38, to undergo a catalytic conversion reaction. The reacted material undergoes gas-solid separation in the settling tank 33. The resulting reaction oil and gas are sent to the oil-gas stabilization system via pipeline 34. The separated, unregenerated catalyst enters the first regenerator 2 via the unregenerated inclined tube 35. In the first regenerator 2, it undergoes first regeneration by contacting first regeneration gas from pipeline 1, resulting in first flue gas and semi-regenerated catalyst. The semi-regenerated catalyst enters the second regenerator 4 via the semi-regeneration pipeline 3 and is controlled by the slide valve 36. In the second regenerator 4, the semi-regenerated catalyst undergoes second regeneration by contacting second regeneration gas from pipeline 7, resulting in regenerator and second flue gas. The regenerator is recycled back to the catalytic conversion reactor 32 via pipeline 6.

[0070] Figure 3 This is a preferred embodiment of the bio-fermentation unit in the method provided by the present invention. The fermentation raw material gas is introduced into the purification device 15 via pipeline 14 for purification to remove impurities from the first flue gas, resulting in purified flue gas. The purified flue gas is then introduced into the fermentation device 17 via pipeline 16 for fermentation, resulting in fermentation tail gas and mash.

[0071] The mash is fed into the distillation unit 19 via pipeline 18 for separation to obtain aqueous ethanol and bacterial residue. The aqueous ethanol is fed into the ethanol dehydration unit 21 via pipeline 20 for dehydration, and the obtained ethanol is sent out via pipeline 11. The bacterial residue is fed into the protein separation unit 23 via pipeline 22 to separate and obtain concentrated protein solution. The concentrated protein solution is fed into the protein drying unit 25 via pipeline 24 for drying to obtain protein feed. The protein feed is sent out of the reaction system via pipeline 12.

[0072] 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.

[0073] The present invention will be further described in detail below through embodiments, but these embodiments do not limit the scope of the invention. Unless otherwise specified, the experimental instruments and raw materials involved in the following embodiments are commercially available products.

[0074] The hydrocarbon oil feedstock used in the examples and comparative examples is Anqing feedstock oil, the properties of which are shown in Table 1.

[0075] 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.

[0076] In the examples and comparative examples, the first regenerator is a bubbling bed, and the second regenerator is a rapid bed.

[0077] Table 1

[0078] Table 2

[0079] Example 1 use Figure 1-3 The experiment was conducted according to the flowchart shown. The hydrocarbon feedstock was introduced into the catalytic conversion reactor via pipeline. The hydrocarbon feedstock contacted the regenerator from the regeneration inclined tube to undergo a catalytic conversion reaction. The reacted material underwent gas-solid separation in a settling tank, yielding reacted oil and gas and the catalyst to be recycled. The conditions in the catalytic conversion reactor included: a reaction temperature of 620 °C, a catalyst-to-oil ratio of 10, and a reaction time of 3 s. The separated, unregenerated catalyst enters the first regenerator via an inclined tube, where it undergoes first regeneration by contacting the first regeneration gas, yielding first flue gas and semi-regenerated catalyst. The first flue gas, after energy recovery, is sent to a bio-fermentation unit for fermentation, producing fermentation tail gas, ethanol, and protein feed. A portion of the fermentation tail gas is recycled back to the first regenerator. The conditions for the first regeneration include: a regeneration temperature of 700 ℃; an average catalyst residence time of 10 min; an apparent gas linear velocity of 0.8 m / s; and a bed density of 450 kg / m³. 3 The first regeneration gas is O2 + CO2, comprising 76.47% by volume CO2 and 25.33% by volume O2; *Clostridium ethanoliferum* with microbial accession number DSM 19630 is used. Clostridium autoethanogenum The fermentation was carried out using acetic acid bacteria (DSMZ, Germany) at a temperature of 30 °C and a pressure of 0.5 MPa in the fermenter; the cell concentration was 9.05 g / L, and the first flue gas feed rate was 5.5 SCFM.

[0080] The semi-regenerated catalyst is introduced into a second regenerator and contacted with the second regeneration gas for second regeneration, yielding a regenerated catalyst and a second flue gas. The conditions for the second regeneration include: a regeneration temperature of 680 ℃; an average catalyst residence time of 3 min; a gas apparent linear velocity of 2 m / s; and a bed density of 200 kg / m³. 3 The second regenerated gas is O2 + CO2, comprising 79% by volume CO2 and 21% by volume O2. The regenerator is circulated back to the catalytic conversion reactor via pipeline; the second flue gas is sent to the energy recovery unit for energy recovery.

[0081] The reaction conditions and results are shown in Table 3.

[0082] Example 2 The method of utilizing catalytic cracking flue gas in Example 2 is basically similar to that in Example 1, except that the regeneration temperature in the first regenerator is 670 °C; the reaction conditions and reaction results are shown in Table 3.

[0083] Example 3 The method of utilizing catalytic cracking flue gas in Example 3 is basically similar to that in Example 1, except that the regeneration temperature in the first regenerator is 740 °C; the reaction conditions and reaction results are shown in Table 3.

[0084] Example 4 The method of utilizing catalytic cracking flue gas in Example 4 is basically similar to that in Example 1, except that the regeneration temperature in the first regenerator is 780 °C; the reaction conditions and reaction results are shown in Table 3.

[0085] Example 5 The method for utilizing catalytic cracking flue gas in Example 5 is basically similar to that in Example 1, except that the catalyst bed density in the first regenerator is 410 kg / m³. 3 The reaction conditions and results are shown in Table 3.

[0086] Table 3

[0087] The data in the table above shows that the present invention provides a method to make better use of flue gas and significantly reduce carbon dioxide emissions by first subjecting the carbonized catalyst to incomplete combustion to generate more CO for bio-fermentation to produce ethanol.

[0088] Example 6 The method of utilizing catalytic cracking flue gas in Example 6 is basically similar to that in Example 1, except that the first regeneration gas includes 63.23% by volume of CO2 and 36.77% by volume of O2; the reaction conditions and reaction results are shown in Table 4.

[0089] Example 7 The method of utilizing catalytic cracking flue gas in Example 7 is basically similar to that in Example 1, except that: the first regeneration gas is O2 + second flue gas + fermentation tail gas; the reaction conditions and reaction results are shown in Table 4.

[0090] Example 8 The method of utilizing catalytic cracking flue gas in Example 8 is basically similar to that in Example 1, except that the first regeneration gas is O2 + the second flue gas; the reaction conditions and reaction results are shown in Table 4.

[0091] Example 9 The method of utilizing catalytic cracking flue gas in Example 9 is basically similar to that in Example 1, except that: the first regeneration gas is O2 + air; the first regeneration gas is air; and the reaction conditions and reaction results are shown in Table 4.

[0092] Example 10 The method of utilizing catalytic cracking flue gas in Example 10 is basically similar to that in Example 1, except that: the first regeneration gas is O2 + air + second flue gas; the first regeneration gas is air; and the reaction conditions and reaction results are shown in Table 4.

[0093] Comparative Example 1 Comparative Example 1 according to Appendix Figure 2 The experiment was conducted using a process where the first flue gas was not sent into the bio-fermentation unit for fermentation.

[0094] The reaction conditions and results are shown in Table 4.

[0095] Comparative Example 2 The utilization method of catalytic cracking flue gas in Comparative Example 2 is basically similar to that in Example 1, except that the operating conditions in the first regenerator and the second regenerator are different; the reaction conditions and reaction results are shown in Table 4.

[0096] Table 4

[0097] As can be seen from the results in Tables 3 and 4, the method of the present invention can significantly reduce carbon dioxide emissions and increase the proportion of CO in the first flue gas. By sending the first flue gas into the bio-fermentation unit for fermentation with acetic acid bacteria, the CO in the flue gas can be converted into high-value products such as ethanol.

[0098] Compared with Comparative Example 2, the method provided by the present invention performs incomplete regeneration by contacting the first regeneration gas with a high-density catalyst in the first regenerator, resulting in a higher CO content in the first flue gas, which is beneficial for reducing carbon dioxide emissions.

[0099] 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.

[0100] 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.

[0101] 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 utilizing catalytic cracking flue gas, characterized in that, The method includes: The hydrocarbon feedstock is brought into contact with the catalytic conversion catalyst in a catalytic conversion reactor to carry out a catalytic conversion reaction. The reaction stream is then separated to obtain the reacted oil and gas and the unused catalyst with carbon deposits. The catalyst to be generated is fed into the first regenerator for first regeneration to obtain first flue gas and semi-regenerated catalyst; Part or all of the first flue gas is fed into a biological fermentation unit to ferment the first flue gas and 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 second flue gas. The first regenerator is selected from one or a combination of bubbling bed, turbulent bed and fast bed; the regeneration temperature of the first regenerator is 600-900 ℃; the second regenerator is selected from one or a combination of bubbling bed, turbulent bed and fast bed.

2. The utilization method according to claim 1, wherein, The regeneration temperature for the first regeneration is 680-780 ℃; the conditions for the first regeneration include: 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 400-700 kg / m³. 3 Preferably 450-600 kg / m 3 .

3. The utilization method according to claim 1, wherein, The conditions for the second regeneration 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 120-450 kg / m³. 3 Preferably 180-300 kg / m 3 .

4. The utilization method according to claim 1, wherein, The first regeneration gas introduced into the first regenerator is selected from one or a mixture of several of the following: air, oxygen-enriched air, oxygen, CO2, second flue gas, and fermentation tail gas; and / or 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, first flue gas, fermentation tail gas, and CO2.

5. The utilization method according to claim 4, wherein, The oxygen content in the first regenerated gas is 20-80% by volume.

6. The utilization method according to claim 1, wherein, The CO content in the first flue gas is 10-50% by volume; the molar ratio of CO to CO2 in the first flue gas is 0.2-1.

5. Optionally, the method further includes: recovering energy from the first flue gas to obtain fermentation raw material gas, and sending the fermentation raw material gas into the biological fermentation unit.

7. The method of utilization according to claim 1, wherein, The method for fermenting the first flue gas includes: The first flue gas is 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.

8. The utilization method according to claim 7, wherein, The acetic acid bacteria were selected from Clostridium difficile, a self-producing ethanol bacterium with the microbial accession number DSM 19630. Clostridium autoethanogenum Clostridium ethanoliferum produced by the organism (DSMZ, Germany) and microbial accession number DSM23693. Clostridium autoethanogenum A mixture of one or two of the following (DSMZ, Germany).

9. The utilization method according to claim 1, wherein, The carbon content of the regenerator is 0-0.05% by weight.

10. The utilization method according to claim 1, wherein, The conditions for the catalytic conversion reaction include: a reaction temperature of 450-700 ℃, a time of 1-10 seconds, and a catalyst-to-oil ratio of (1-100):1; The catalytic conversion reactor is selected from one or a combination of two types of riser reactors and fluidized bed reactors; Optionally, the hydrocarbon feedstock is selected from petroleum hydrocarbons and / or mineral oils, wherein the petroleum hydrocarbons are selected from one or more combinations of gasoline, diesel, vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, hydrotreated heavy oil, hydrotreated tail oil, extracted oil, and low-quality recycled oil; and the mineral oils are selected from one or more combinations of coal liquefaction oil, oil sands oil, and shale oil.

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