Light hydrocarbon catalytic cracking device and process

Abstract

The invention provides a light hydrocarbon catalytic cracking device and process. The light hydrocarbon catalytic cracking device comprises a liquid feeding lifting pipe, a light hydrocarbon expanding reactor, a reactant lifting pipe and a light hydrocarbon settler, one end of the liquid feeding lifting pipe penetrates into a shell at the bottom of the light hydrocarbon expanding reactor and enters the light hydrocarbon expanding reactor, and a gas light hydrocarbon feeding distributor, a gas distribution plate and a catalyst dense-phase bed section are sequentially arranged at the inner lower part of an annular space formed by the liquid feeding lifting pipe and the shell of the light hydrocarbon expanding reactor from bottom to top; a rectifying component is arranged at the inner upper part of the light hydrocarbon expanding reactor; the top of the light hydrocarbon expanding reactor is communicated with the bottom of a reactant lifting pipe, the top of the reactant lifting pipe penetrates into a shell at the bottom of the light hydrocarbon settler to enter the shell and is communicated with separation equipment in the light hydrocarbon settler, and a gas outlet of the separation equipment is connected with an oil gas outlet pipeline; the liquid feeding lifting pipe comprises a catalyst pre-lifting section, a liquid light hydrocarbon feeding and reaction section and an outlet adjusting section which are communicated in sequence from bottom to top.

Description

Technical Field

[0001] The invention relates to a light hydrocarbon catalytic cracking device and process, belonging to the technical field of catalytic cracking. Background Art

[0002] Early catalytic cracking used aluminum silicate beads as catalysts, and the reactor was a dense bed reactor; with the emergence of highly active and highly selective zeolite catalysts, the reaction rate of petroleum hydrocarbons with the catalyst was greatly accelerated, and the reactor used a fast-transport bed riser, which was beneficial to improving the yield and selectivity of liquid products.

[0003] Compared with dense bed reactors, riser reactors have made great progress in structure and operation mode, mainly in the mixing of oil, gas and catalyst in the feed section, rapid separation of outlet products, reduction of temperature gradient on the riser section and reduction of return, etc. Since the highly active zeolite catalyst greatly improves the reaction intensity, Kellogg, UOP, Shell and other companies have developed fast transport bed reactors, namely riser reactors. Since riser reactors have good elasticity and flexibility, emphasize the primary cracking of heavy oil, and the light oil yield and selectivity are relatively ideal, this type of reactor still has strong vitality. Sinopec Research Institute of Petrochemical Technology proposed a variable diameter riser in the prior art such as CN99105903, CN99109193, and CN99105904, and added a section of expansion in the middle of the riser to form a fluidized bed reaction section, thereby strengthening the secondary reaction of the generated gasoline. Studies have shown that this type of reactor can perform primary cracking of heavy oil and secondary conversion of gasoline in the same reactor; however, it is difficult for this type of reactor to crack recycled light hydrocarbons (gasoline) into cracked gas with smaller molecules. The liquefied gas yield reported in the literature is less than 30%, and the propylene yield is less than 9%.

[0004] The re-reaction of light hydrocarbons entering the catalytic cracking unit is a research hotspot. In order to improve the quality of gasoline, reduce the olefin content of gasoline and increase the yield of cracked gas, the prior art discloses a large number of technical measures for recycling light hydrocarbons, of which there are two typical ones: (1) recycling gasoline or other light hydrocarbons to the original heavy oil riser, generally injecting them into the upstream of the feedstock oil nozzle, such as USP5043522 and USP5846403 disclose injecting catalytic cracking gasoline into the upstream of the feedstock oil nozzle, and catalytically converting it using a high-temperature, high-activity regenerated catalyst; CN1160746A also discloses a method of injecting low-quality gasoline such as straight-run gasoline and coking gasoline into the lower part of the riser reaction, so that it contacts the regenerated catalyst first; (2) using a separate gasoline or light hydrocarbon riser for recycling, such as CN1069054A and USP3784463 use a catalytic cracking unit with a double riser reactor for reaction, injecting low-quality gasoline including catalytic cracking crude gasoline into the gasoline riser reactor, and using high temperature and large agent-to-oil ratio reaction conditions to achieve catalytic modification of the low-quality gasoline to improve the yield of liquefied gas and the octane number of gasoline. The molecules generated after the light hydrocarbon feed contacts the catalyst are relatively small, and the volume expands significantly, which affects the heavy oil feed in the upper part of the catalytic cracking riser reactor and the contact between the heavy oil and the catalyst. Therefore, in order to avoid a significant negative impact on the heavy oil reaction, the proportion of light hydrocarbon recycling is relatively low in method (1). Method (2) uses a separate light hydrocarbon recycling reactor on the basis of the traditional heavy oil reactor to recycle or secondary crack the light hydrocarbon components. However, the light hydrocarbon molecules are small, and the required reactor has a high catalyst density requirement. The traditional riser cannot well meet the requirements of the contact reaction between the light hydrocarbon molecules and the catalyst.

[0005] CN204455003U proposes a light hydrocarbon cracking device, which realizes the contact reaction between light hydrocarbons and catalysts in an expanded shell through light hydrocarbons in a light hydrocarbon feed primary separator and catalysts transported from a catalyst riser. In the expanded shell, the catalyst enters the catalyst distributor from the outlet of the riser, and the light hydrocarbons enter the light hydrocarbon distributor. The catalyst and the light hydrocarbons are contacted and strengthened through the catalyst distributor and the light hydrocarbon distributor. The internal components of this type of reactor are relatively complex, and can only achieve enhanced contact between a stream of light hydrocarbon feed and the catalyst.

[0006] Operation analysis of catalytic cracking unit combining heavy oil MIP and inferior catalytic cracking diesel LTAG process [J]. Liu Tianbo, Lin Chunyang, Tang Jinlian, Petroleum Refining and Chemical Industry, Issue 6, 2020, pp. 72-78. The article discloses a dual-reactor process combining a heavy oil MIP reactor and an inferior catalytic cracking diesel LTAG reactor, but the reactors involved, such as internal components and processes, such as the optimal operating range and the destination of oil, gas and catalyst are completely different from the present invention.

[0007] Therefore, providing a new type of light hydrocarbon catalytic cracking device and process has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0008] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide a light hydrocarbon catalytic cracking device.

[0009] Another object of the present invention is to provide a light hydrocarbon catalytic cracking process.

[0010] In order to achieve the above objectives, on the one hand, the present invention provides a light hydrocarbon catalytic cracking device, wherein the light hydrocarbon catalytic cracking device comprises: a liquid feed riser, a light hydrocarbon expansion reactor, a reactant riser and a light hydrocarbon settler;

[0011] Wherein, the liquid feed lifting pipe is arranged at the lower end of the light hydrocarbon expansion reactor, one end of the liquid feed lifting pipe penetrates the shell at the bottom of the light hydrocarbon expansion reactor and enters the light hydrocarbon expansion reactor, and the two are coaxially arranged, the inner lower part of the annular space formed by the liquid feed lifting pipe and the shell of the light hydrocarbon expansion reactor is provided with a gas light hydrocarbon feed distributor, a gas distribution plate and a catalyst dense phase bed section in sequence from bottom to top, and the inner upper part of the light hydrocarbon expansion reactor (preferably close to the top position in the light hydrocarbon expansion reactor) is provided with a rectifying component; the top of the light hydrocarbon expansion reactor is connected to the bottom of the reactant lifting pipe, the top of the reactant lifting pipe penetrates the shell at the bottom of the light hydrocarbon settler and enters the light hydrocarbon settler, and is connected to the separation equipment in the light hydrocarbon settler, and the gas outlet of the separation equipment is connected to the oil and gas outlet pipeline;

[0012] The liquid feed lifting pipe includes, from bottom to top, a catalyst pre-lifting section, a liquid light hydrocarbon feed and reaction section, and an outlet adjustment section which are connected in sequence; a pre-lifting gas inlet is provided at the bottom of the catalyst pre-lifting section, and the middle and lower parts of the catalyst pre-lifting section are connected to the regeneration inclined pipe; a liquid light hydrocarbon feed nozzle is provided at the bottom of the liquid light hydrocarbon feed and reaction section, an oil and gas outlet is provided on the upper part of the side wall of the adjustment section, and the top of the adjustment section is connected to the rectifying component.

[0013] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the catalyst pre-lifting section is connected to the liquid light hydrocarbon feed and the reaction section directly or through a properly expanded truncated cone.

[0014] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the pre-lift gas inlet is also provided with a gas distribution member.

[0015] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the liquid light hydrocarbon feed nozzle is symmetrically arranged along the liquid light hydrocarbon feed and the bottom of the reaction section at the same height, and the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon feed nozzle is arranged slightly upward or slightly downward, that is, the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon feed nozzle forms a certain angle with the horizontal plane, one side of the angle is in the horizontal plane, and the other side can be upward or downward, preferably a downward arrangement is adopted, and the size of the angle is 5°-60°, preferably 15°-45°.

[0016] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the length of the catalyst pre-lift section is generally 3-8m, preferably 4-6m, and the length of the liquid light hydrocarbon feed and reaction section is generally 3-20m, preferably 5-15m.

[0017] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the oil and gas outlet of the liquid feed lifting pipe is arranged on the upper part of the side wall of the outlet adjustment section and close to the top, and its shape is rectangular or elliptical, and the sum of the areas of the oil and gas outlets is 60%-400% of the cross-sectional area of ​​the outlet adjustment section.

[0018] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the oil and gas outlet is installed with a ceramic inner core wear-resistant lining.

[0019] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the oil and gas outlet of the liquid feed riser is connected to a side channel, whose cross section is rectangular or elliptical, and the side channel is arranged in the same horizontal plane, and the axis of the side channel is at an angle of 30°-60° with the radial extension line of the liquid feed riser. In this way, the oil and gas and catalyst ejected from the side channel can form a rotation along the central axis in the upper part of the light hydrocarbon expansion reactor, that is, the oil and gas and catalyst at the oil and gas outlet of the liquid feed riser can form a vortex in the middle and upper part of the light hydrocarbon expansion reactor, so as to reduce the side wall effect inside it, so that the oil and gas and catalyst in the two reactors, namely the liquid feed riser and the light hydrocarbon expansion reactor, can be fully mixed.

[0020] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the ratio of the inner diameter of the catalyst pre-lifting section to the inner diameter of the liquid light hydrocarbon feed and reaction section is 1:1-1.8, preferably 1:1.1-1.4.

[0021] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the bottom of the light hydrocarbon expanded diameter reactor is an inverted dome type, the middle is a cylindrical type, and the top is a dome type or a truncated cone type.

[0022] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the gas light hydrocarbon feed distributor is a multi-layer concentric annular feed pipe with multiple gas light hydrocarbon feed nozzles, or a branch-shaped distribution pipe with multiple gas light hydrocarbon feed nozzles.

[0023] As a specific embodiment of the light hydrocarbon catalytic cracking device described above, the gas distribution plate is evenly provided with a plurality of channels, the total opening rate is 5%-50%, preferably 15%-35%, and the pore size of the channel is 5-60mm, preferably 10-30mm.

[0024] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, a plurality of holes evenly distributed on the gas distribution plate are installed or coated with ceramic wear-resistant linings.

[0025] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the rectifying component is a conical cylinder located at the top of the liquid feed riser, and its vertical projection is a circle. The ratio of the diameter of the circle to the diameter of the cross-section of the light hydrocarbon expanded reactor is 0.5-0.9:1, preferably 0.65-0.85:1.

[0026] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the rectifying component is located in the upper part of the light hydrocarbon expansion reactor, that is, by creating a relatively narrow space in this section, the flow rate of oil, gas and catalyst is accelerated, thereby bringing out the oil, gas and catalyst in the lower part of the light hydrocarbon expansion reactor.

[0027] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the height from the bottom of the light hydrocarbon expanded reactor to the gas distribution plate is 0.1-1m, preferably 0.2-0.6m; the height from the gas distribution plate to the oil and gas outlet arranged on the upper side wall of the liquid feed riser is 1-8m, preferably 2-5m.

[0028] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the length of the reactant riser is 3-30m, preferably 5-15m.

[0029] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, wherein the separation device is one or a combination of an inertial separator and a cyclone separator, preferably a cyclone separator;

[0030] The inertial separator is one of an umbrella-shaped, inverted L-shaped, T-shaped, three-leaf-shaped or ejection-shaped type, and the cyclone separator is a volute-shaped or straight-cut cyclone separator. In some embodiments of the present invention, the separation device may be, for example, a 1-3 stage cyclone separator.

[0031] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, a gas collecting device is also arranged on the top of the light hydrocarbon settler, and the gas outlet of the separation device is connected to the oil and gas outlet pipeline via the gas collecting device.

[0032] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present invention, the reactant riser and the shell of the light hydrocarbon settler form an annular space, the inner lower part of the annular space is a stripping section, and the stripping section is provided with a steam distributor.

[0033] In the light hydrocarbon catalytic cracking device provided by the present invention, a separation device is arranged in the light hydrocarbon settler, and the top of the reactant lifting pipe is connected to the separation device, and the reaction oil and gas and the catalyst in the light hydrocarbon expansion reactor are transported to the inlet of the separation device arranged in the light hydrocarbon settler through the reactant lifting pipe. The catalyst with deposited coke and the reaction oil and gas can be separated by the separation device, and the reaction oil and gas can enter the subsequent reaction oil and gas fractionation tower from the pipeline at the top of the separation device, that is, the oil and gas outlet pipeline, while the catalyst with deposited coke falls from the bottom outlet of the separation device into the stripping section at the lower part of the light hydrocarbon settler. In the stripping section, water vapor is injected through a steam distributor to blow out the volatile hydrocarbon gas entrained on the catalyst to be generated, that is, the catalyst with deposited coke, and then merge into the gas phase reaction product, that is, the reaction oil and gas.

[0034] As a specific embodiment of the light hydrocarbon catalytic cracking device described above in the present invention, the lower part of the stripping section is also connected to a spent catalyst inclined tube, through which the spent catalyst can be introduced into a regenerator for charring regeneration or introduced into a heavy oil reactor to improve its reaction performance.

[0035] The light hydrocarbon catalytic cracking device provided by the present invention can form a dual reactor system with the heavy oil catalytic cracking / catalytic cracking reactor, and the two share a catalyst regeneration system; after the reaction, the oil and gas can be collected into an oil and gas separation system, or they can enter their own oil and gas separation systems. The light hydrocarbon catalytic cracking device provided by the present invention can also be used alone, that is, it can form a light hydrocarbon catalytic cracking reaction-regeneration system with the catalyst regeneration system. Under normal circumstances, the regeneration system needs to take measures such as supplementary combustion to maintain the heat balance of the device.

[0036] The raw material of the heavy oil catalytic cracking / catalytic cracking reactor is petroleum hydrocarbons and / or other mineral oils. Specifically, the petroleum hydrocarbons can be selected from one or a combination of vacuum gas oil (VGO), atmospheric gas oil (AGO), coker gas oil (CGO), deasphalted oil (DAO), vacuum residue oil (VR), atmospheric residue oil (AR) and hydrogenated heavy oil; other mineral oils are selected from one or a combination of coal liquefaction oil, oil sand oil and shale oil;

[0037] Preferably, the raw material of the heavy oil catalytic cracking / catalytic cracking reactor is selected from one or a combination of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, and hydrogenated heavy oil. Among them, VGO, AGO, CGO, DAO, VR, and AR are the whole fraction or part of the fraction that is not hydrogenated, or the whole fraction or part of the fraction that is hydrogenated.

[0038] On the other hand, the present invention also provides a light hydrocarbon catalytic cracking process, wherein the light hydrocarbon catalytic cracking process is implemented using the light hydrocarbon catalytic cracking device described above, and comprises the following steps:

[0039] Step (1): the pre-lift gas and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the catalyst pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the liquid light hydrocarbon feed and reaction section along with the lifting of the pre-lift gas;

[0040] Step (2): spraying liquid light hydrocarbons into the bottom of the liquid light hydrocarbon feed and reaction section through a liquid light hydrocarbon feed nozzle, and making it contact with the fluidized catalyst to achieve gasification of the liquid light hydrocarbon and cracking reaction; gaseous light hydrocarbons and cracking reaction products, pre-lifting gas and catalyst ascend along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed from the oil and gas outlet to enter the upper part of the light hydrocarbon expansion reactor in a horizontal direction. Due to the increase in the horizontal cross-sectional area of ​​the light hydrocarbon expansion reactor, the linear velocity of the oil and gas flow is greatly reduced, so that most of the catalyst falls into the catalyst dense bed section, while most of the oil and gas (including gaseous light hydrocarbons and cracking reaction products, pre-lifting gas) and a small amount of catalyst bypass the rectifying component and enter the reactant riser;

[0041] Step (3): The gaseous light hydrocarbons enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through the gaseous light hydrocarbon feed distributor and the gas distribution plate and come into contact with the catalyst falling into the catalyst dense phase bed section to undergo a cracking reaction, and the gaseous light hydrocarbons and their cracking reaction products and the catalyst continue to ascend and bypass the rectifying component and enter the reactant riser;

[0042] Step (4): The two streams of materials in step (3) and step (4), i.e., most of the oil and gas and a small amount of catalyst in step (3), the gaseous light hydrocarbons and their cracking reaction products and the catalyst in step (4) enter the separation equipment through the reactant lifting pipe for separation, and the obtained gas is discharged through the oil and gas outlet pipeline.

[0043] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, the process further includes: allowing the spent catalyst obtained by separation through the separation equipment to enter the stripping section, injecting water vapor into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and allowing it to enter the separation equipment to merge with the reaction product.

[0044] In the above-mentioned light hydrocarbon catalytic cracking process of the present invention, since a rectifying component is arranged at the upper part of the light hydrocarbon expansion reactor, under the influence of the rectifying component, the gas linear velocity is accelerated, so that the catalyst in the light hydrocarbon expansion reactor can be brought out and enter the upper reactant riser together with the gas. In the reactant riser, the gas-solid fluidization of the reactant riser is transformed into a rapid conveying bed, and the above-mentioned two streams of materials are allowed to enter the separation equipment through the reactant riser for separation. The obtained catalyst is input from the lower part of the separation equipment and enters the stripping section of the light hydrocarbon settler. The surface of this type of catalyst is coke generated during the reaction process, which is called a catalyst to be regenerated. The obtained gas is discharged through the oil and gas outlet pipeline. The lower part of the stripping section is connected to an inclined tube for the catalyst to be regenerated. The catalyst to be regenerated can be first introduced into the regenerator through the inclined tube for air coking regeneration, and then introduced into the catalyst pre-lifting section through the regeneration inclined tube for recycling, or introduced into the heavy oil reactor for improving its reaction performance.

[0045] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, the process also includes: first mixing gaseous light hydrocarbons and water vapor, and then allowing the resulting mixture to enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through a gas light hydrocarbon feed distributor and a gas distribution plate, so as to adjust the fluidization state of the catalyst and the partial pressure of hydrocarbons, thereby strengthening the cracking reaction path of the hydrocarbons. The present invention does not make specific requirements on the amount of water vapor used, and its amount can be reasonably adjusted according to the actual needs of on-site operations.

[0046] As a specific embodiment of the light hydrocarbon catalytic cracking process described above, the gas phase superficial linear velocity of the gas phase light hydrocarbons and their cracking reaction products and water vapor in the light hydrocarbon expansion reactor is maintained at 0.7-1.4 m / s to maintain a turbulent state in the light hydrocarbon expansion reactor, thereby enhancing the contact between the oil and gas and the catalyst.

[0047] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, the temperature of the catalytic cracking or catalytic cracking catalyst after high-temperature regeneration, that is, the catalyst before contact with the oil agent, is 660-760°C, the oil and gas outlet temperature of the liquid feed riser is 560-650°C, preferably 580-630°C, and the temperature of the catalyst dense phase bed section at the lower part of the light hydrocarbon expanded reactor is 540-630°C, preferably 560-620°C.

[0048] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, the apparent residence time of oil and gas in the liquid feed riser is 0.8-2s, the apparent residence time of oil and gas in the gaseous light hydrocarbon feed in the light hydrocarbon expansion reactor is 1.5-10s, preferably 2-5s, and the apparent residence time of oil and gas in the reactant riser is 0.5-5s.

[0049] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, liquid light hydrocarbons enter the liquid light hydrocarbon feed and reaction section through a liquid light hydrocarbon feed nozzle by steam atomization or direct mechanical spraying; preferably, a liquid light hydrocarbon feed nozzle atomized by atomizing steam is used to achieve the atomization of light hydrocarbons by utilizing the collision of water vapor and liquid light hydrocarbons inside the nozzle.

[0050] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process of the present invention, the liquid light hydrocarbon includes one or a combination of olefin-rich gasoline, diesel, and light hydrocarbons with carbon atoms of 4-8 that are not rich in olefins or rich in olefins. Among them, the olefin-rich gasoline can be selected from one or a combination of gasoline obtained by the process provided by the present invention, conventional catalytic cracking gasoline, other catalytic cracking gasoline, coking gasoline, thermal cracking gasoline, and thermal cracking gasoline; the light hydrocarbons that are not rich in olefins can be selected from one or a combination of straight-run naphtha, straight-run gasoline, hydrogenated naphtha, alkanes with carbon atoms of 4-8, and raffinate oil.

[0051] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process of the present invention, the gaseous light hydrocarbon (i.e., the light hydrocarbon after gasification) includes olefin-rich light hydrocarbons with carbon atoms of 3-8, etc., preferably olefin-rich light hydrocarbons with carbon atoms of 4-6. In some embodiments of the present invention, the gaseous light hydrocarbons can be selected from one or a combination of post-etherification C4 light hydrocarbons, post-etherification light gasoline, catalytic light gasoline, coking light gasoline, and thermal cracking light gasoline.

[0052] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process of the present invention, the pre-lifting gas includes water vapor and / or dry gas.

[0053] As a specific embodiment of the light hydrocarbon catalytic cracking process described above in the present invention, the process is applicable to all types of catalytic cracking or catalytic cracking catalysts, the active components of which are selected from Y or HY type zeolites containing or not containing rare earths, ultra-stable Y type zeolites containing or not containing rare earths, ZSM-5 series zeolites, high-silicon zeolites with a five-membered ring structure prepared by other methods, one, a combination of two or three, and an amorphous silica-alumina catalyst.

[0054] Compared with the prior art, the beneficial effects achieved by the present invention include:

[0055] (1) The light hydrocarbon catalytic cracking device described in the present invention is a parallel-connected light hydrocarbon catalytic cracking reaction device under non-hydrogen conditions, which can realize the feeding of two streams of light hydrocarbons, that is, one stream of light hydrocarbons is a gas phase feed, and the other stream of light hydrocarbons is a liquid phase feed and effective contact between them and the catalyst. The liquid feed riser is used to process liquid light hydrocarbons. The liquid light hydrocarbons can be directly introduced for processing. In the liquid light hydrocarbon feed and the feed section at the bottom of the reaction section of the liquid feed riser, the liquid light hydrocarbons react with the catalytic cracking or catalytic cracking catalyst after high-temperature regeneration, which is conducive to realizing the cracking reaction of this stream of liquid light hydrocarbons;

[0056] (2) The present invention connects and couples the liquid feed riser in the light hydrocarbon catalytic cracking unit with the light hydrocarbon expansion reactor through a special design, so that the catalyst which has been in contact with the liquid light hydrocarbon and still has high activity at a high temperature can be deposited in the middle and lower part of the light hydrocarbon expansion reactor, i.e., the catalyst dense phase bed section, and then contacts and reacts with the gasified light hydrocarbon, i.e., the gas phase light hydrocarbon feed;

[0057] (3) The present invention achieves controllable flow of catalyst and oil gas by making the light hydrocarbon catalytic cracking device have a special reactor configuration and connection mode, and constructs a reaction environment for enhanced contact between two streams of light hydrocarbon feed and catalyst, so that enhanced contact between light hydrocarbon and catalyst can be achieved, so as to achieve the purpose of sufficient reaction of light hydrocarbon, and also improve the specific processing capacity of the device and the processing efficiency of light hydrocarbon;

[0058] (4) The present invention arranges an internal component in the upper part of the light hydrocarbon expansion reactor in the light hydrocarbon catalytic cracking device, and the internal component can effectively regulate the controllable flow of oil, gas and catalyst in the light hydrocarbon expansion reactor and the stability of gas-solid fluidization. Specifically, the internal component includes two parts: an outlet adjustment section of the liquid feed riser and a rectifying component in the light hydrocarbon expansion reactor. Among them, the outlet adjustment section of the liquid feed riser effectively adjusts the flow direction of oil, gas and catalyst at the outlet of the liquid feed riser, changes the oil and gas flow direction from upward to horizontal and rotates along the axial direction of the riser, and forms a vortex in the middle and upper part of the light hydrocarbon expansion reactor, so as to reduce the wall effect inside it, so that the oil, gas and catalyst in the two reactors, namely the liquid feed riser and the light hydrocarbon expansion reactor, are fully mixed; the ratio of the diameter of the vertical projection (circle) of the rectifying component in the light hydrocarbon expansion reactor to the diameter of the cross section of the light hydrocarbon expansion reactor is 0.5-0.9:1, which can accelerate the gas linear velocity, so that the catalyst in the light hydrocarbon expansion reactor can be brought out and enter the upper reactant riser together with the gas, so as to effectively improve the gas-solid fluidization stability in the light hydrocarbon expansion reactor.

[0059] (5) The light hydrocarbon catalytic cracking device of the present invention has multiple operation modes and can flexibly adjust the product structure. For example, the light hydrocarbon catalytic cracking device can be used alone, that is, it can be used alone with the catalyst regeneration system to form a light hydrocarbon catalytic cracking reaction-regeneration system. Under normal circumstances, the regeneration system needs to take measures such as supplementary combustion to maintain the heat balance of the device. It can also be used together with the heavy oil catalytic cracking / catalytic cracking reactor to form a dual reactor system. The two share a catalyst regeneration system. After the reaction, the oil and gas can be collected into an oil and gas separation system, or they can enter their own oil and gas separation systems.

[0060] (6) The light hydrocarbon catalytic cracking device and process described in the present invention can recycle light hydrocarbons, gasoline or diesel rich in C4-C8 olefins throughout the entire plant; it can improve product quality, regulate the diesel-gasoline specific energy, and further increase the cracking gas output of the entire plant, that is, increase the output of raw materials required for light hydrocarbon processing units such as MTBE, light gasoline etherification, and polypropylene, thereby regulating the refining product structure of the entire plant and responding to the refining transformation needs of petrochemical enterprises under the "dual carbon" situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 This is a schematic diagram of the structure of the light hydrocarbon catalytic cracking device provided in Example 1 of the present invention.

[0063] Figure 2 A cross-sectional schematic diagram of the outlet adjustment section in the light hydrocarbon catalytic cracking unit provided in Example 1 of the present invention.

[0064] Figure 3 Schematic diagram of the structure of the light hydrocarbon catalytic cracking riser reactor used in Comparative Examples 1 to 3.

[0065] Description of main figures:

[0066] 1. Catalyst pre-lifting section, 2. Liquid light hydrocarbon feed and reaction section, 3. Export adjustment section, 4. Light hydrocarbon expansion reactor, 5. Reactant lifting pipe, 6. Light hydrocarbon settler, 7. Stripping section, 8. Oil and gas export pipeline, 9. Pre-lifting gas inlet, 10. Regeneration inclined tube, 11. Liquid light hydrocarbon, 12. Gas phase light hydrocarbon feed, 13. Gas light hydrocarbon feed distributor, 14. Gas distribution plate, 15. Rectification component, 16. Oil and gas outlet, 17. Catalyst to be regenerated inclined tube;

[0067] 31. Pre-lifting section, 32. Riser reaction section, 33. Gas-phase light hydrocarbon feed loop. DETAILED DESCRIPTION

[0068] It should be noted that the term "comprises" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0069] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "middle", "top" and "bottom" are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0070] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0071] In addition, the terms "disposed" and "connected" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] "Scope" disclosed in the present invention is given in the form of lower limit and upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, a range of 60-120 and 80-110 is listed, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4 and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

[0073] In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviation of these numerical combinations.

[0074] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0075] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0076] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0077] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the attached table, drawings and examples. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0078] Device Embodiment

[0079] Example 1

[0080] This embodiment provides a light hydrocarbon catalytic cracking device, and its structural schematic diagram is as follows: Figure 1 As shown, from Figure 1 It can be seen that the light hydrocarbon catalytic cracking unit includes:

[0081] Liquid feed riser, light hydrocarbon expansion reactor 4, reactant riser 5 and light hydrocarbon settler 6;

[0082] Wherein, the liquid feed lifting pipe is arranged at the lower end of the light hydrocarbon expansion reactor, one end of the liquid feed lifting pipe penetrates the shell at the bottom of the light hydrocarbon expansion reactor 4 and enters the light hydrocarbon expansion reactor 4, and the two are coaxially arranged, and the lower part of the annular space formed by the liquid feed lifting pipe and the shell of the light hydrocarbon expansion reactor 4 is sequentially arranged with a gas light hydrocarbon feed distributor 13, a gas distribution plate 14 and a catalyst dense phase bed section (not shown in the figure) from bottom to top, and a rectifying component 15 is arranged near the top of the light hydrocarbon expansion reactor 4; the top of the light hydrocarbon expansion reactor 4 is connected with the bottom of the reactant lifting pipe 5, and the top of the reactant lifting pipe 5 penetrates the shell at the bottom of the light hydrocarbon settler 6 and enters the light hydrocarbon settler 6, and is connected with the separation equipment in the light hydrocarbon settler 6, and the gas outlet of the separation equipment is connected with the oil and gas outlet pipeline 8 via the gas collection equipment (not shown in the figure);

[0083] The liquid feed lifting pipe includes, from bottom to top, a catalyst pre-lifting section 1, a liquid light hydrocarbon feed and reaction section 2, and an outlet adjustment section 3 which are connected in sequence. In this embodiment, the liquid light hydrocarbon feed and reaction section 2 and the outlet adjustment section 3 are arranged as a whole, and the outlet adjustment section 3 and part of the liquid light hydrocarbon feed and reaction section 2 are located in the light hydrocarbon expansion reactor 4; a pre-lifting gas inlet 9 is arranged at the bottom of the catalyst pre-lifting section 1, and the middle and lower parts of the catalyst pre-lifting section 1 are connected to the regeneration inclined pipe 10; a liquid light hydrocarbon feed nozzle (not shown in the figure) is arranged at the bottom of the liquid light hydrocarbon feed and reaction section 2, an oil and gas outlet 16 is arranged on the upper part of the side wall of the outlet adjustment section 3, and the top of the outlet adjustment section 3 is connected to the rectifying component 15.

[0084] The liquid light hydrocarbon feed nozzles are arranged symmetrically along the liquid light hydrocarbon feed and around the reaction section 2, and the cross-sectional schematic diagram of the outlet adjustment section 3 is as follows: Figure 2 As shown, the oil and gas outlet 16 is arranged at the upper part of the side wall of the outlet adjustment section 3 and close to the top. The oil and gas outlet 16 is installed with a ceramic inner core wear-resistant lining. The catalyst pre-lifting section 1 is connected to the liquid light hydrocarbon feed and reaction section 2 through a moderately expanded truncated cone. The bottom of the light hydrocarbon expansion reactor 4 is an inverted dome type, the middle is a cylindrical type, and the top is a dome type or a truncated cone type. The gas light hydrocarbon feed distributor 13 is a multi-layer concentric annular feed pipe with multiple gas light hydrocarbon feed nozzles. The rectifying component 15 is a conical cylinder, and its vertical projection is a circle. The shells of the reactant lifting pipe 5 and the light hydrocarbon settler 6 form an annular space. The inner lower part of the annular space is a stripping section 7. The stripping section 7 is provided with a steam distributor (not shown in the figure). The lower part of the stripping section 7 is also connected to an inclined tube 17 for the catalyst to be produced. The separation equipment is a 1-3 stage cyclone separator, and the cyclone separator is a volute type or a straight cut type cyclone separator.

[0085] The operation process of the light hydrocarbon catalytic cracking device provided in this embodiment includes:

[0086] The pre-lifting gas enters from the pre-lifting gas inlet 9 provided at the bottom of the catalyst pre-lifting section 1, contacts with the catalytic cracking or catalytic cracking catalyst after high-temperature regeneration from the regeneration inclined tube 10 connected to the catalyst pre-lifting section 1, and fluidizes it and moves upward along the catalyst pre-lifting section 1; enters the appropriately expanded liquid light hydrocarbon feed and reaction section 2, and the liquid light hydrocarbon 11 enters the bottom of the liquid light hydrocarbon feed and reaction section 2 through the liquid light hydrocarbon feed nozzle, contacts with the fluidized catalyst rising from the bottom, realizes the gasification of the liquid light hydrocarbon and its cracking reaction, and the gas phase light hydrocarbon and its reaction products, The pre-lifting gas and the catalyst continue to ascend along the liquid light hydrocarbon feed and reaction section 2, enter the outlet adjustment section 3 at the top of the liquid light hydrocarbon feed and reaction section 2, and are ejected from the side channel of the outlet adjustment section 3 to enter the upper part of the light hydrocarbon expansion reactor 4. Due to the increase in the horizontal cross-section of the light hydrocarbon expansion reactor 4, the linear velocity of the oil and gas flow is greatly reduced, causing most of the catalyst to fall into the lower part of the light hydrocarbon expansion reactor 4; while most of the oil and gas and a small amount of catalyst, recorded as material 1, bypass the rectifying component 15 in the light hydrocarbon expansion reactor 4 and enter the upper reactant lifting pipe 5;

[0087] The gas phase light hydrocarbon feed 12 enters the bottom of the light hydrocarbon expansion reactor 4 through the gas light hydrocarbon feed distributor 13, and then enters the catalyst dense phase bed section of the light hydrocarbon expansion reactor 4 through the holes of the gas distribution plate 14 above, thereby achieving high-efficiency contact between light hydrocarbons and catalysts and achieving the reaction of light hydrocarbons. Due to the influence of the rectifying component 15 at the upper part of the catalyst dense phase bed section 4, the gas linear velocity is accelerated, so that the gas phase light hydrocarbons and their cracking reaction products can bring out the catalyst in the catalyst dense phase bed section 4 and enter the upper reactant riser 5 together with the gas, and the gas phase light hydrocarbons and their cracking reaction products and catalysts are recorded as material 2;

[0088] The materials 1 and 2 are transported through the reactant lifting pipe 5 and enter the separation equipment at the top of the light hydrocarbon settler 6 to separate the gas from the catalyst. Under the action of this separation equipment, the gas enters the gas collecting equipment at the top of the light hydrocarbon settler and is discharged from the oil and gas outlet pipeline at the top. The catalyst is discharged from the lower part of the separation equipment and enters the stripping section 7 of the light hydrocarbon settler 6. The surface of this type of catalyst is coke generated during the reaction process, which is called a catalyst to be regenerated. In the stripping section 7, water vapor is injected into the stripping section 7 through a steam distributor to strip the volatile hydrocarbon gas entrained on the catalyst to be regenerated and enter the separation equipment to merge with the gas phase reaction product. The lower part of the stripping section 7 is connected to a catalyst to be regenerated inclined pipe 17, and the catalyst to be regenerated is introduced into the regenerator through the catalyst to be regenerated by air burning, and then introduced into the catalyst pre-lifting section 1 through the regeneration inclined pipe 10 for recycling, or introduced into the heavy oil reactor for improving its reaction performance.

[0089] Process Example

[0090] Example 2

[0091] The present embodiment provides a process for producing low-carbon olefins by catalytic cracking of light hydrocarbons, which is implemented by using the light hydrocarbon catalytic cracking device provided in Example 1. In the light hydrocarbon catalytic cracking device, the axial direction of the liquid light hydrocarbon spraying nozzle of the liquid light hydrocarbon is set in a slightly downwardly inclined manner, and the angle between the axial direction and the horizontal plane is 30°. The shape of the oil and gas outlet 16 is elliptical, and the sum of the areas of the oil and gas outlets is 70% of the cross-sectional area of ​​the outlet adjustment section. The oil and gas outlet 16 is externally connected to a symmetrically arranged elliptical side channel, which is arranged in the same horizontal plane, and the axis of the side channel is at an angle of 30° to the radial extension line of the liquid feed lifting pipe. The catalyst pre-lifting section 1 and the liquid light hydrocarbon feed are connected to the catalyst pre-lifting section 1. The lengths of the feed and reaction sections 2 are 5m and 15m respectively, and the inner diameters are 0.5m and 0.6m respectively, that is, the ratio of the inner diameters of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feed and reaction section 2 is 1:1.2, the height of the light hydrocarbon expansion reactor 4 is 3m, and the inner diameter is 1.9m, the gas distribution plate 14 is evenly provided with a plurality of channels, the total opening rate is 6%, the pore diameter of the channels is 5mm, the channels are installed or coated with ceramic wear-resistant linings, the rectifying component 15 is a conical cylinder, and its vertical projection is a circle, the diameter of the circle is 1.6m, that is, the ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon expansion reactor 4 is 0.84:1, the length of the reactant lifting pipe 5 is 18m, and the inner diameter is 0.6m;

[0092] Wherein, the process comprises the following specific steps:

[0093] The pre-lifting gas (steam or dry gas) and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the catalyst pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the liquid light hydrocarbon feed and reaction section along with the lifting of the pre-lifting gas;

[0094] Liquid light hydrocarbons are sprayed into the bottom of the liquid light hydrocarbon feed and reaction section through a liquid light hydrocarbon feed nozzle, and are brought into contact with the fluidized catalyst to achieve gasification of the liquid light hydrocarbons and cracking reaction thereof; gaseous light hydrocarbons and cracking reaction products thereof, pre-lifting gas and catalysts ascend along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed from the oil and gas outlet to enter the upper part of the light hydrocarbon expansion reactor in a horizontal direction. Due to the increase in the horizontal cross-section of the light hydrocarbon expansion reactor, the linear velocity of the oil and gas flow is greatly reduced, causing most of the catalyst to fall into the catalyst dense phase bed section at the lower part of the light hydrocarbon expansion reactor 4, while most of the oil and gas and a small amount of catalyst, recorded as material 1, bypass the rectifying component and enter the reactant riser;

[0095] The gaseous light hydrocarbons enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through the gaseous light hydrocarbon feed distributor and the gas distribution plate and undergo cracking reaction after contacting the catalyst falling into the catalyst dense phase bed section. The gaseous light hydrocarbons and their cracking reaction products and catalyst, recorded as material 2, continue to move upward and bypass the rectifying component and enter the reactant riser; wherein, the light hydrocarbon expansion reactor is in a turbulent state;

[0096] Material 1 and material 2 enter the separation equipment through the reactant lifting pipe for separation, and the resulting gas is discharged through the oil and gas outlet pipeline;

[0097] The spent catalyst obtained by separation equipment enters the stripping section, and water vapor is injected into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and enter the separation equipment to merge with the gas phase reaction product. The spent catalyst is then introduced into the regenerator through a spent catalyst inclined pipe for air charring regeneration, and finally introduced into the catalyst pre-lifting section through a regeneration inclined pipe for recycling.

[0098] The property parameters of the liquid light hydrocarbons, gaseous light hydrocarbons (C4 after etherification) and catalyst used in this example are shown in Tables 1 to 3, respectively. The operating conditions, product distribution and main properties of the products in the example are listed in Table 4. This example adopts medium-severity operating conditions.

[0099] Example 3

[0100] This embodiment provides a process for producing low-carbon olefins by catalytic cracking of light hydrocarbons. The only difference between this embodiment and Example 2 is the operating conditions. This embodiment adopts more severe operating conditions. The operating conditions, product distribution and main properties of the products are also listed in Table 4.

[0101] Example 4

[0102] The present embodiment provides a process for producing low-carbon olefins by catalytic cracking of light hydrocarbons, which is implemented by using the light hydrocarbon catalytic cracking device provided in Example 1. In the light hydrocarbon catalytic cracking device, the axial direction of the liquid light hydrocarbon spraying nozzle of the liquid light hydrocarbon is set in a slightly upward tilted manner, and the angle between the axial direction and the horizontal plane is 45°. The shape of the oil and gas outlet 16 is rectangular, and the sum of the areas of the oil and gas outlets is 400% of the cross-sectional area of ​​the outlet adjustment section. The oil and gas outlet 16 is externally connected to three centrally symmetrically arranged rectangular side channels, and the side channels are arranged in the same horizontal plane, and the axis of the side channels is at an angle of 60° to the radial extension line of the liquid feed lifting pipe. The catalyst pre-lifting section 1 and the liquid light hydrocarbon feed are connected to the catalyst pre-lifting section 1. The lengths of the feed and reaction sections 2 are 3m and 16m respectively, and the inner diameters are 0.3m and 0.48m respectively, that is, the ratio of the inner diameters of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feed and reaction section 2 is 1:1.6, the height of the light hydrocarbon expansion reactor 4 is 3.5m, and the inner diameter is 2.1m, the gas distribution plate 14 is evenly provided with a plurality of channels, the total opening rate is 25%, the aperture of the channel is 60mm, the channel is installed or coated with a ceramic wear-resistant lining, the rectifying component 15 is a conical cylinder, and its vertical projection is a circle, the diameter of the circle is 1.3m, that is, the ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon expansion reactor 4 is 0.62:1, the length of the reactant lifting pipe 5 is 16m, and the inner diameter is 0.6m;

[0103] Wherein, the process comprises the following specific steps:

[0104] The pre-lifting gas (steam or dry gas) and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the catalyst pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the liquid light hydrocarbon feed and reaction section along with the lifting of the pre-lifting gas;

[0105] Liquid light hydrocarbons are sprayed into the bottom of the liquid light hydrocarbon feed and reaction section through a liquid light hydrocarbon feed nozzle, and are brought into contact with the fluidized catalyst to achieve gasification of the liquid light hydrocarbons and cracking reaction thereof; gaseous light hydrocarbons and cracking reaction products thereof, pre-lifting gas and catalysts ascend along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed from the oil and gas outlet to enter the upper part of the light hydrocarbon expansion reactor in a horizontal direction. Due to the increase in the horizontal cross-section of the light hydrocarbon expansion reactor, the linear velocity of the oil and gas flow is greatly reduced, causing most of the catalyst to fall into the catalyst dense phase bed section at the lower part of the light hydrocarbon expansion reactor 4, while most of the oil and gas and a small amount of catalyst, recorded as material 1, bypass the rectifying component and enter the reactant riser;

[0106] The gaseous light hydrocarbons enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through the gaseous light hydrocarbon feed distributor and the gas distribution plate and undergo cracking reaction after contacting the catalyst falling into the catalyst dense phase bed section. The gaseous light hydrocarbons and their cracking reaction products and catalyst, recorded as material 2, continue to move upward and bypass the rectifying component and enter the reactant riser; wherein, the light hydrocarbon expansion reactor is in a turbulent state;

[0107] Material 1 and material 2 enter the separation equipment through the reactant lifting pipe for separation, and the resulting gas is discharged through the oil and gas outlet pipeline;

[0108] The spent catalyst obtained by separation equipment enters the stripping section, and water vapor is injected into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and enter the separation equipment to merge with the gas phase reaction product. The spent catalyst is then introduced into the regenerator through a spent catalyst inclined pipe for air charring regeneration, and finally introduced into the catalyst pre-lifting section through a regeneration inclined pipe for recycling.

[0109] The property parameters of the liquid light hydrocarbons, gaseous light hydrocarbons (C4 after etherification) and catalyst used in this embodiment are also the same as those in Example 1, as shown in Tables 1 to 3, respectively. The operating conditions, product distribution and main properties of the products in this embodiment are also listed in Table 4. This embodiment adopts less severe operating conditions.

[0110] Comparative Example 1

[0111] This comparative example provides a process for producing low-carbon olefins by catalytic cracking of gas-phase light hydrocarbons. Figure 3 The light hydrocarbon catalytic cracking riser reactor shown in the figure is realized, wherein the light hydrocarbon catalytic cracking riser reactor comprises a pre-lift section 31, a riser reaction section 32 and a light hydrocarbon settler 6, the pre-lift section 31 is connected to the riser reaction section 32 through a moderately expanded truncated cone, and the lengths of the pre-lift section 31 and the riser reaction section 32 are 5m and 36m respectively, and the inner diameters are 0.5m and 0.6m respectively, the bottom of the pre-lift section 31 is provided with a pre-lift gas inlet 9, and the middle and lower parts of the pre-lift section 31 are connected to the regeneration inclined pipe 10; the riser reaction section 32 The top of the riser penetrates into the shell at the bottom of the light hydrocarbon settler 6 and enters the light hydrocarbon settler 6, and is connected to the separation equipment in the light hydrocarbon settler 6, and the gas outlet of the separation equipment is connected to the oil and gas outlet pipeline 8 via the gas collection equipment (not shown in the figure); the riser reaction section 32 and the shell of the light hydrocarbon settler 6 form an annular space, and the inner lower part of the annular space is the stripping section 7, and the stripping section 7 is provided with a steam distributor (not shown in the figure), and the lower part of the stripping section 7 is also connected to the catalyst inclined tube 17 to be produced; a gas-phase light hydrocarbon feed ring pipe 33 is provided at the bottom of the riser reaction section 32;

[0112] The separation equipment is a 1-3 stage cyclone separator, and the cyclone separator is a volute type or a straight cut type cyclone separator;

[0113] The process for producing low-carbon olefins by catalytic cracking of gas-phase light hydrocarbons comprises the following specific steps:

[0114] The pre-lifting gas (steam or dry gas) and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the riser reaction section along with the pre-lifting gas.

[0115] The gaseous light hydrocarbons enter the reaction section of the riser through the gaseous light hydrocarbon feed ring pipe and are brought into contact with the fluidized catalyst to achieve cracking reaction of the gaseous light hydrocarbons; the gaseous light hydrocarbons and their cracking reaction products, pre-lifting gas and catalyst ascend along the reaction section of the riser and enter the separation equipment for separation, and the resulting gas is discharged through the oil and gas outlet pipeline;

[0116] The spent catalyst obtained by separation equipment enters the stripping section, and water vapor is injected into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and enter the separation equipment to merge with the gas phase reaction product. The spent catalyst is then introduced into the regenerator through a spent catalyst inclined pipe for air charring regeneration, and finally introduced into the catalyst pre-lifting section through a regeneration inclined pipe for recycling.

[0117] The property parameters of the gaseous light hydrocarbons (C4 after etherification) and the catalyst used in this comparative example are shown in Tables 2 and 3, respectively. The operating conditions, product distribution and main properties of the products in the comparative example are listed in Table 4, where the processed light hydrocarbon processing volume is recorded as a benchmark M kg / h.

[0118] Comparative Example 2

[0119] This comparative example provides a process for producing low-carbon olefins by catalytic cracking of liquid light hydrocarbons, which is implemented by using a light hydrocarbon catalytic cracking riser reactor. The light hydrocarbon catalytic cracking riser reactor is different from the light hydrocarbon catalytic cracking riser reactor used in comparative example 1 only in that: no gas phase light hydrocarbon feed ring pipe 33 is provided at the bottom of the riser reaction section 32, but a liquid light hydrocarbon feed nozzle is provided at a height of 4 m from the bottom of the riser reaction section 32, and the liquid light hydrocarbon feed nozzle is arranged slightly upward (the inclination angle is 30°, that is, the angle between the axial direction of the liquid light hydrocarbon ejected by the liquid light hydrocarbon feed nozzle and the horizontal plane is 30°);

[0120] The process for producing low-carbon olefins by catalytic cracking of liquid light hydrocarbons comprises the following specific steps:

[0121] The pre-lifting gas (steam or dry gas) and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the riser reaction section along with the pre-lifting gas.

[0122] Liquid light hydrocarbons enter the reaction section of the riser through the liquid light hydrocarbon feed nozzle and come into contact with the fluidized catalyst to achieve gasification and cracking reaction of the liquid light hydrocarbons; gaseous light hydrocarbons and their cracking reaction products, pre-lifting gas and catalyst ascend along the reaction section of the riser and enter the separation equipment for separation, and the resulting gas is discharged through the oil and gas outlet pipeline;

[0123] The spent catalyst obtained by separation equipment enters the stripping section, and water vapor is injected into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and enter the separation equipment to merge with the gas phase reaction product. The spent catalyst is then introduced into the regenerator through a spent catalyst inclined pipe for air charring regeneration, and finally introduced into the catalyst pre-lifting section through a regeneration inclined pipe for recycling.

[0124] The property parameters of the liquid light hydrocarbons and catalyst used in this comparative example are shown in Table 1 and Table 3, respectively. The operating conditions, product distribution and main properties of the products in the comparative example are listed in Table 4, where the processed light hydrocarbon processing volume is recorded as a benchmark M kg / h.

[0125] Comparative Example 3

[0126] This comparative example provides a process for producing low-carbon olefins by catalytic cracking of liquid light hydrocarbons and gaseous light hydrocarbons, which is implemented by using a light hydrocarbon catalytic cracking riser reactor. The light hydrocarbon catalytic cracking riser reactor is different from the light hydrocarbon catalytic cracking riser reactor used in comparative example 1 only in that: a gaseous light hydrocarbon feed ring 33 is arranged at the bottom of the riser reaction section 32, and a liquid light hydrocarbon feed nozzle is arranged at a height of 4m at the bottom of the riser reaction section 32. The liquid light hydrocarbon feed nozzle is arranged slightly downward (the inclination angle is 30°, that is, the angle between the axial direction of the liquid light hydrocarbon ejected by the liquid light hydrocarbon feed nozzle and the horizontal plane is 30°);

[0127] The process for producing low-carbon olefins by catalytic cracking of liquid light hydrocarbons and gaseous light hydrocarbons comprises the following specific steps:

[0128] The pre-lifting gas (steam or dry gas) and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the riser reaction section along with the pre-lifting gas.

[0129] The gaseous light hydrocarbons enter the riser reaction section through the gaseous light hydrocarbon feed ring pipe and are brought into contact with the fluidized catalyst to achieve cracking reaction of the gaseous light hydrocarbons; the gaseous light hydrocarbons and their cracking reaction products, pre-lifting gas and catalyst ascend along the riser reaction section and contact with the liquid light hydrocarbons entering the riser reaction section through the liquid light hydrocarbon feed nozzle to achieve gasification of the liquid light hydrocarbons and cracking reaction; the gaseous light hydrocarbons and their cracking reaction products, pre-lifting gas and catalyst continue to ascend along the riser reaction section and enter the separation equipment for separation, and the resulting gas is discharged through the oil and gas outlet pipeline;

[0130] The spent catalyst obtained by separation equipment enters the stripping section, and water vapor is injected into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained in the spent catalyst and enter the separation equipment to merge with the gas phase reaction product. The spent catalyst is then introduced into the regenerator through a spent catalyst inclined pipe for air charring regeneration, and finally introduced into the catalyst pre-lifting section through a regeneration inclined pipe for recycling.

[0131] The property parameters of the liquid light hydrocarbons, gaseous light hydrocarbons (C4 after etherification) and catalyst used in this comparative example are shown in Tables 1 to 3, respectively. The operating conditions, product distribution and main properties of the products in the comparative example are listed in Table 4.

[0132] Table 1 Properties of liquid light hydrocarbons

[0133] Components Light gasoline Pyrolysis Gasoline Properties <![CDATA[Density (20 °C), kg / m 3 > 698 Hydrocarbon composition, v% Saturated hydrocarbons 25 Olefins 68 Aromatics 7 Distillation range, wt%~℃ Initial distillation point 35 10％ 52 50％ 69 90％ 85 EBP (End Boil Point) 99

[0134] Table 2 Properties of gas phase light hydrocarbons

[0135]

[0136]

[0137] Table 3 Catalyst properties

[0138] Main Catalyst catalyst Zeolite Type ZSM-5 is the main Chemical composition, wt% Alumina 52.1 Sodium oxide 0.15 Sieve composition, wt% 0-40μm 25.54 40-80μm 48.05 >110μm 26.41 <![CDATA[Specific surface area / m 2 ·g -1 > 210 <![CDATA[Deposition density / g·cm -3 > 0.79 <![CDATA[Apparent density / g·cm -3 > 0.75 Micro-anti-activity, % 58 Sieve composition, wt% 0.28

[0139] The catalysts in Table 3 were produced by the Lanzhou Catalyst Plant of China National Petroleum Corporation.

[0140] Table 4 Operating conditions and product distribution

[0141]

[0142]

[0143] In summary, the process for producing low-carbon olefins by catalytic cracking of light hydrocarbons provided in Example 2 of the present invention is implemented by the light hydrocarbon catalytic cracking device provided in Example 1, and the processes provided in Comparative Examples 1 to 3 are implemented by existing light hydrocarbon catalytic cracking riser reactors, and Comparative Example 1 only uses gaseous light hydrocarbon feed, Comparative Example 2 only uses liquid light hydrocarbon feed, and Comparative Example 3 uses a combination of gaseous light hydrocarbon and liquid light hydrocarbon feed. As can be seen from Table 4, both Example 2 and Comparative Example 3 of the present invention use two streams of light hydrocarbon feed. In comparison, the use of the light hydrocarbon catalytic cracking device described in the present invention can significantly increase the processing volume of light hydrocarbons, and can greatly increase the yield of liquefied gas and propylene, and can also increase the content of aromatics in gasoline. This shows that the light hydrocarbon catalytic cracking device and process described in the present invention can significantly increase the processing volume of light hydrocarbons and the cracking depth of light hydrocarbons, and is an excellent light hydrocarbon catalytic cracking reactor;

[0144] It can also be seen from Table 4 that Example 3 of the present invention adopts high severity operation, which can achieve a higher yield of liquefied gas and propylene, and the aromatic content in gasoline is very high, and aromatics can be further extracted; while Example 4 of the present invention appropriately modifies the device parameters, examines the parameters of the relative boundary of the device, and operates at a lower severity, which can appropriately produce more liquefied gas and propylene, and the olefin content in gasoline also decreases significantly. It can be seen from the three embodiments that the relevant parameters of the device provided by the present invention can be changed in a large range, and the range of process operating conditions is wide, which is suitable for moderately producing more liquefied gas, producing more liquefied gas, and maximizing the production of liquefied gas.

[0145] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims

1. A light hydrocarbon catalytic cracking device, characterized in that: The light hydrocarbon catalytic cracking device comprises a liquid feed riser, a light hydrocarbon expansion reactor, a reactant riser and a light hydrocarbon settler; The liquid feed lifting pipe is arranged at the lower end of the light hydrocarbon expansion reactor, one end of the liquid feed lifting pipe penetrates the shell at the bottom of the light hydrocarbon expansion reactor and enters the light hydrocarbon expansion reactor, and the two are coaxially arranged, the inner lower part of the annular space formed by the liquid feed lifting pipe and the shell of the light hydrocarbon expansion reactor is provided with a gas light hydrocarbon feed distributor, a gas distribution plate and a catalyst dense phase bed section in sequence from bottom to top, and the inner upper part of the light hydrocarbon expansion reactor is provided with a rectifying component; the top of the light hydrocarbon expansion reactor is connected with the bottom of the reactant lifting pipe, the top of the reactant lifting pipe penetrates the shell at the bottom of the light hydrocarbon settler and enters the light hydrocarbon settler, and is connected with the separation equipment in the light hydrocarbon settler, and the gas outlet of the separation equipment is connected with the oil and gas outlet pipeline; The liquid feed lifting pipe includes, from bottom to top, a catalyst pre-lifting section, a liquid light hydrocarbon feed and reaction section, and an outlet adjustment section which are connected in sequence; a pre-lifting gas inlet is provided at the bottom of the catalyst pre-lifting section, and the middle and lower parts of the catalyst pre-lifting section are connected to the regeneration inclined pipe; a liquid light hydrocarbon feed nozzle is provided at the bottom of the liquid light hydrocarbon feed and reaction section, an oil and gas outlet is provided at the upper part of the side wall of the outlet adjustment section, and the top of the outlet adjustment section is connected to the rectifying component.

2. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that: The liquid light hydrocarbon feed nozzle is symmetrically arranged along the liquid light hydrocarbon feed and around the bottom of the reaction section. The axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon feed nozzle is upward or downward, and the angle between it and the horizontal plane is 5°-60°.

3. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that: The oil and gas outlet of the liquid feed lifting pipe is arranged on the upper part of the side wall of the outlet adjustment section and close to the top. Its shape is rectangular or elliptical. The sum of the areas of the oil and gas outlets is 60%-400% of the cross-sectional area of ​​the outlet adjustment section.

4. The light hydrocarbon catalytic cracking device according to claim 1 or 3, characterized in that: The oil and gas outlet of the liquid feed lifting pipe is connected to a side channel, whose cross section is rectangular or elliptical. The side channel is arranged in the same horizontal plane, and the axis of the side channel forms an angle of 30°-60° with the radial extension line of the liquid feed lifting pipe.

5. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that: The ratio of the inner diameters of the catalyst pre-lift section and the liquid light hydrocarbon feed and reaction section is 1:1-1.

8.

6. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that: The bottom of the light hydrocarbon expansion reactor is in an inverted dome shape, the middle is in a cylindrical shape, and the top is in a dome shape or a truncated cone shape.

7. The light hydrocarbon catalytic cracking device according to claim 1 or 6, characterized in that: The gas light hydrocarbon feed distributor is a multi-layer concentric annular feed pipe with a plurality of gas light hydrocarbon feed nozzles, or a branch-shaped distribution pipe with a plurality of gas light hydrocarbon feed nozzles.

8. The light hydrocarbon catalytic cracking device according to claim 1 or 6, characterized in that: The gas distribution plate is evenly provided with a plurality of pores, the total opening rate is 5%-50%, and the pore diameter of the pores is 5-60 mm.

9. The light hydrocarbon catalytic cracking device according to claim 1 or 6, characterized in that: The rectifying component is a conical cylinder located at the top of the liquid feed riser, and its vertical projection is a circle. The ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon expansion reactor is 0.5-0.9:

1.

10. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that: The reactant riser and the shell of the light hydrocarbon settler form an annular space, the inner lower part of the annular space is a stripping section, and the stripping section is provided with a steam distributor; Preferably, the lower part of the stripping section is also connected to an inclined tube for the catalyst to be produced.

11. A light hydrocarbon catalytic cracking process, characterized in that: The light hydrocarbon catalytic cracking process is implemented by using the light hydrocarbon catalytic cracking device according to any one of claims 1 to 10, and comprises the following steps: Step (1): the pre-lift gas and the catalytic cracking or catalytic cracking catalyst after high temperature regeneration enter the catalyst pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe respectively for contact fluidization, and the fluidized catalyst enters the liquid light hydrocarbon feed and reaction section along with the lifting of the pre-lift gas; Step (2): spraying liquid light hydrocarbons into the bottom of the liquid light hydrocarbon feed and reaction section through a liquid light hydrocarbon feed nozzle, and making it contact with the fluidized catalyst to achieve gasification of the liquid light hydrocarbons and cracking reaction; gaseous light hydrocarbons and cracking reaction products, pre-lifting gas and catalyst ascend along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed from the oil and gas outlet to enter the upper part of the light hydrocarbon expansion reactor in a horizontal direction, and most of the catalyst falls into the catalyst dense bed section, while most of the oil and gas and a small amount of catalyst bypass the rectifying component and enter the reactant lifting pipe; Step (3): The gaseous light hydrocarbons enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through the gaseous light hydrocarbon feed distributor and the gas distribution plate and come into contact with the catalyst falling into the catalyst dense phase bed section to undergo a cracking reaction, and the gaseous light hydrocarbons and their cracking reaction products and the catalyst continue to ascend and bypass the rectifying component and enter the reactant riser; Step (4): The two streams of materials in step (3) and step (4) enter the separation equipment through the reactant lifting pipe for separation, and the obtained gas is discharged through the oil and gas outlet pipeline.

12. The light hydrocarbon catalytic cracking process according to claim 11, characterized in that: The process also includes: allowing the spent catalyst separated by the separation device to enter the stripping section, injecting water vapor into the stripping section through a steam distributor to strip out the volatile hydrocarbon gas entrained by the spent catalyst and merge it into the reaction product.

13. The light hydrocarbon catalytic cracking process according to claim 11 or 12, characterized in that: The process also includes: Firstly, gaseous light hydrocarbons and water vapor are mixed, and then the obtained mixture is passed through a gaseous light hydrocarbon feed distributor and a gas distributor plate into a catalyst dense phase bed section of a light hydrocarbon expansion reactor; Preferably, the gas phase superficial linear velocity of the gas phase light hydrocarbons and their cracking reaction products and water vapor in the light hydrocarbon expansion reactor is maintained at 0.7-1.4 m / s to maintain a turbulent state in the light hydrocarbon expansion reactor.

14. The light hydrocarbon catalytic cracking process according to claim 11 or 12, characterized in that: The temperature of the catalytic cracking or catalytic cracking catalyst after high-temperature regeneration is 660-760°C, the oil and gas outlet temperature of the liquid feed riser is 560-650°C, and the temperature of the catalyst dense phase bed section at the bottom of the light hydrocarbon expansion reactor is 540-630°C; Preferably, the apparent residence time of oil and gas in the liquid feed riser is 0.8-2s, the apparent residence time of oil and gas in the gaseous light hydrocarbon feed in the light hydrocarbon expansion reactor is 1.5-10s, and the apparent residence time of oil and gas in the reactant riser is 0.5-5s.

15. The light hydrocarbon catalytic cracking process according to claim 11 or 12, characterized in that: The liquid light hydrocarbons include one or a combination of olefin-rich gasoline, diesel, and olefin-free or olefin-rich light hydrocarbons with a carbon number of 4 to 8; Preferably, the gas phase light hydrocarbons include olefin-rich light hydrocarbons with carbon atoms of 3-8.

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