Light hydrocarbon catalytic cracking device and process

Abstract

The application provides a light hydrocarbon catalytic cracking device and process, the light hydrocarbon catalytic cracking device includes liquid feed riser, light hydrocarbon diameter expansion reactor, reactant riser and light hydrocarbon settler;One end of the liquid feed riser penetrates into the shell at the bottom of the light hydrocarbon diameter expansion reactor to enter the light hydrocarbon diameter expansion reactor, the annular space formed by the liquid feed riser and the shell of the light hydrocarbon diameter expansion reactor has a gas light hydrocarbon feed distributor, a gas distribution plate and a catalyst dense bed section arranged from bottom to top in sequence in the lower part, and the upper part of the light hydrocarbon diameter expansion reactor is provided with a flow regulating member;The top of the light hydrocarbon diameter expansion reactor is communicated with the bottom of the reactant riser, the top of the reactant riser penetrates into the shell at the bottom of the light hydrocarbon settler to enter it and is communicated with the separation equipment in the light hydrocarbon settler, and the gas outlet of the separation equipment is connected with the oil gas outlet pipeline;The liquid feed riser includes a catalyst pre-lifting section, a liquid light hydrocarbon feed and reaction section and an outlet adjusting section communicated in sequence from bottom to top.

Description

TECHNICAL FIELD

[0001] The present application relates to a light hydrocarbon catalytic cracking device and process, and belongs to the technical field of catalytic cracking. BACKGROUND

[0002] Early catalytic cracking uses aluminum silicate beads as catalyst, and the reactor adopts a dense phase bed reactor; with the emergence of high-activity and high-selectivity zeolite catalysts, the reaction rate of petroleum hydrocarbons and catalysts is greatly accelerated, and the reactor adopts a fast conveying bed riser, which is conducive to improving the liquid product yield and selectivity.

[0003] The riser reactor has great progress in structure and operation mode compared with the dense phase bed reactor, mainly in the mixing of oil gas and catalyst in the feed section, the rapid separation of outlet products, the reduction of temperature gradient on the riser cross section, and the reduction of return, etc. Due to the high activity of zeolite catalysts, the reaction intensity is greatly improved, and Kellogg, UOP, Shell and other companies have developed a fast conveying bed reactor, i.e. a riser reactor. Due to the good flexibility and flexibility of the riser reactor, the emphasis is on 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 Petroleum Chemical Industry Research Institute proposed a variable-diameter riser in the prior art CN99105903, CN99109193, CN99105904, etc. A section of the riser is expanded in the middle part, thereby forming a fluidized bed reaction section, and further strengthening the secondary reaction of the generated gasoline. Research shows that this type of reactor is a reactor that can perform primary cracking of heavy oil in the same reactor while considering the secondary conversion of gasoline. However, it is difficult for this type of reactor to crack the recycled light hydrocarbon (gasoline) into smaller cracking gas. The literature reports that the liquid gas yield is less than 30%, and the propylene yield is less than 9%.

[0004] Light hydrocarbon into catalytic cracking device is a research hotspot. In order to improve the quality of gasoline, reduce the olefin content of gasoline and improve the yield of cracking gas, a large number of technical measures for recycling light hydrocarbon are disclosed in the prior art, and there are two typical methods: (1) recycling gasoline or other light hydrocarbons to the original heavy oil riser, which is generally injected into the upstream of the feed oil nozzle, such as USP5043522 and USP5846403, which discloses that the catalytic cracking gasoline is injected into the upstream of the feed oil nozzle, and the high temperature and high activity regenerated catalyst is used for catalytic conversion; CN1160746A also discloses a kind of low quality gasoline such as straight-run gasoline, coking gasoline, etc. Injected into the lower part of the riser reactor, so that it is preferentially contacted with the regenerated catalyst; (2) using a separate gasoline or light hydrocarbon riser for recycling, such as CN1069054A and USP3784463, which uses a catalytic cracking device with double riser reactors for reaction, and low quality gasoline including catalytic cracking gasoline is injected into the gasoline riser reactor, and the high temperature and large catalyst / oil ratio reaction conditions are used to realize the catalytic upgrading of low quality gasoline, so as to improve the yield of liquefied gas and the octane number of gasoline. The molecules generated after the light hydrocarbon feed contacts with the catalyst are relatively small, and the volume expansion is obvious, 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 the negative impact of the heavy oil reaction, the proportion of light hydrocarbon recycling in method (1) is low. Method (2) uses a separate light hydrocarbon recycling reactor based on the traditional heavy oil reactor to recycle or secondary crack the light hydrocarbon components, but the light hydrocarbon molecules are small, and the required reactor has a high requirement for catalyst density, and the traditional riser cannot 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 hydrocarbon and catalyst in an expanded shell by light hydrocarbon feed preliminary separator and catalyst transported from the catalyst riser. In the expanded shell, the catalyst enters the catalyst distributor from the riser outlet, and the light hydrocarbon enters the light hydrocarbon distributor. The catalyst and the light hydrocarbon realize the contact strengthening through the catalyst distributor and the light hydrocarbon distributor. The inner structure of the reactor is relatively complex, and only one light hydrocarbon feed and catalyst can realize the strengthened contact.

[0006] The article "Analysis of the operation of a catalytic cracking unit with a heavy oil MIP combined with a poor quality catalytic cracking diesel LTAG process" by Liu Tianbo, Lin Chunyang, Tang Jinlian and Shihua in Petroleum Refining and Chemical Industry, No. 6, 2020, pages 72-78 discloses a double reactor process combined with a heavy oil MIP reactor and a poor quality catalytic cracking diesel LTAG reactor, but the reactor involved, such as the inner structure and the process, such as the optimal operation interval and the oil gas and catalyst direction, are completely different from the present application.

[0007] Therefore, providing a new light hydrocarbon catalytic cracking device and process has become a technical problem to be solved in the field. SUMMARY

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

[0009] Another purpose of the present application is also to provide a light hydrocarbon catalytic cracking process.

[0010] In order to achieve the above purposes, in one aspect, the present application provides a light hydrocarbon catalytic cracking device, wherein the light hydrocarbon catalytic cracking device comprises a liquid feed riser, a light hydrocarbon diameter expansion reactor, a reactant riser and a light hydrocarbon settler.

[0011] The liquid feed riser is arranged at the lower end of the light hydrocarbon diameter expansion reactor, one end of the liquid feed riser penetrates into the light hydrocarbon diameter expansion reactor through the shell at the bottom of the light hydrocarbon diameter expansion reactor and is coaxially arranged with the shell, the inner lower part of the annular space formed by the liquid feed riser and the shell of the light hydrocarbon diameter expansion reactor is sequentially provided from bottom to top with a gaseous light hydrocarbon feed distributor, a gas distribution plate and a catalyst dense bed section, and the inner upper part (preferably near the top position inside the light hydrocarbon diameter expansion reactor) of the light hydrocarbon diameter expansion reactor is provided with a flow regulating member; the top of the light hydrocarbon diameter expansion reactor is in communication with the bottom of the reactant riser, the top of the reactant riser penetrates into the light hydrocarbon settler through the shell at the bottom of the light hydrocarbon settler and is in communication with a separation device inside the light hydrocarbon settler, and the gas outlet of the separation device is connected with an oil and gas outlet pipeline.

[0012] The liquid feed riser comprises a catalyst pre-lifting section, a liquid light hydrocarbon feed and reaction section and an outlet adjusting section which are sequentially communicated from bottom to top; the bottom of the catalyst pre-lifting section is provided with a pre-lifting gas inlet, and the middle and lower part of the catalyst pre-lifting section is in communication with a regeneration inclined pipe; the bottom of the liquid light hydrocarbon feed and reaction section is provided with a liquid light hydrocarbon feed nozzle, the upper part of the side wall of the adjusting section is provided with an oil and gas outlet, and the top of the adjusting section is connected with the flow regulating member.

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

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

[0015] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the liquid light hydrocarbon feed nozzles are arranged symmetrically along the same level around the bottom of the liquid light hydrocarbon feed and reaction section, the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon feed nozzles is arranged slightly upward or slightly downward, that is, the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon feed nozzles forms an angle with the horizontal plane, one side of the angle is on the horizontal plane, and the other side can be upward or downward, and preferably arranged downward, the size of the angle is 5°-60°, and preferably 15°-45°.

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

[0017] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the oil and gas outlet of the liquid feed riser is arranged on the upper part of the side wall of the outlet adjustment section and close to the top, and has a rectangular or elliptical shape, 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 application, the oil and gas outlet is provided 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 application, the oil and gas outlet of the liquid feed riser is externally connected with a side passage, which has a rectangular or elliptical cross-section, the side passage is arranged in the same horizontal plane, and the axis of the side passage forms an angle of 30°-60° with the radial extension line of the liquid feed riser. In this way, the oil and gas and catalyst sprayed from the side passage can form a rotation along the central axis in the upper part of the light hydrocarbon diameter expansion reactor, that is, the oil and gas and catalyst of the liquid feed riser can form a cyclone in the middle and upper part of the light hydrocarbon diameter expansion reactor, so as to reduce the edge wall effect in the reactor, and make the oil and gas and catalyst in the two reactors, i.e. the liquid feed riser and the light hydrocarbon diameter expansion reactor, fully mixed.

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

[0021] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the bottom of the light hydrocarbon diameter expansion reactor is in the shape of an inverted dome, the middle part is in the shape of a cylinder, and the top is in the shape of a dome or a circular truncated cone.

[0022] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the gas light hydrocarbon feed distributor is a ring-shaped feed pipe with multiple layers of concentric circles 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 above-mentioned light hydrocarbon catalytic cracking device of the present application, the gas distribution plate is uniformly provided with multiple holes with a total opening rate of 5%-50%, preferably 15%-35%, and a hole diameter of 5-60 mm, preferably 10-30 mm.

[0024] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the multiple holes uniformly provided on the gas distribution plate are installed or coated with a ceramic wear-resistant lining.

[0025] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the flow regulating member is a conical cylinder at the top of the liquid feed riser, with a vertical projection in the shape of a circle, and the ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon diameter expansion reactor is 0.5-0.9:1, preferably 0.65-0.85:1.

[0026] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the flow regulating member is located in the upper part of the light hydrocarbon diameter expansion reactor, i.e. a relatively narrow space is created in this section, thereby accelerating the flow rate of the oil gas and catalyst, and thus bringing out the oil gas and catalyst from the lower part of the light hydrocarbon diameter expansion reactor.

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

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

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

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

[0031] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the top of the light hydrocarbon settler is further provided with a gas collecting device, and the gas outlet of the separation device is connected to the oil gas outlet pipeline through the gas collecting device.

[0032] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the shell of the reactant riser and the light hydrocarbon settler forms 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 application, a separation device is arranged in the light hydrocarbon settler, and the top of the reactant riser is connected to the separation device. The reaction oil gas and 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 riser. The catalyst deposited with coke and the reaction oil gas are separated by the separation device. The reaction oil gas enters the subsequent reaction oil gas fractionating tower through the pipeline at the top of the separation device, i.e. the oil gas outlet pipeline, while the catalyst deposited with coke falls into the stripping section in the lower part of the light hydrocarbon settler from the bottom outlet of the separation device. The steam distributor in the stripping section injects steam to sweep out the volatile hydrocarbon gas carried by the spent catalyst, i.e. the catalyst deposited with coke, and then the volatile hydrocarbon gas is mixed into the reaction product in the gas phase, i.e. the reaction oil gas.

[0034] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking device of the present application, the lower part of the stripping section is further connected to a spent catalyst inclined pipe. The spent catalyst is introduced into the regenerator for coke-burning regeneration or into the heavy oil reactor to improve the reaction performance.

[0035] The light hydrocarbon catalytic cracking device provided by the present application can form a double-reactor system with a heavy oil catalytic cracking / catalytic cracking reactor, and both share a set of catalyst regeneration system. The post-reaction oil gas can be mixed into a set of oil gas separation system or can enter the respective oil gas separation system. The light hydrocarbon catalytic cracking device provided by the present application can also be applied independently, i.e. it is independently combined with a catalyst regeneration system to form a light hydrocarbon catalytic cracking reaction-regeneration system. In general, the regeneration system needs to take measures such as supplemental combustion to maintain the heat balance of the device.

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

[0037] Preferably, the feedstock of the heavy oil catalytic cracking / catalytic cracking reactor is selected from one or a combination of the following: vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, hydrocracked heavy oil. Among them, VGO, AGO, CGO, DAO, VR, AR are full fraction or partial fraction before hydrogenation, or full fraction or partial fraction after hydrogenation.

[0038] In another aspect, the present application also provides a light hydrocarbon catalytic cracking process, wherein the light hydrocarbon catalytic cracking process is realized by using the light hydrocarbon catalytic cracking device described above, comprising the following steps:

[0039] Step (1): The pre-lift gas and the high-temperature regenerated catalytic cracking or catalytic cracking catalyst enter the catalyst pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe respectively to contact fluidization, and the fluidized catalyst is lifted with the pre-lift gas to enter the liquid light hydrocarbon feed and reaction section;

[0040] Step (2): The liquid light hydrocarbon is sprayed into the bottom of the liquid light hydrocarbon feed and reaction section through the liquid light hydrocarbon feed nozzle, and is contacted with the fluidized catalyst to realize the gasification of the liquid light hydrocarbon and its cracking reaction; the gaseous light hydrocarbon and its cracking reaction products, the pre-lift gas and the catalyst go up along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed out from the oil gas outlet along the horizontal direction into the upper part of the light hydrocarbon diameter expansion reactor, and due to the increase of the horizontal cross-sectional area of the light hydrocarbon diameter expansion reactor, the oil gas flow linear velocity is greatly reduced, so that most of the catalyst falls into the catalyst dense bed section, and most of the oil gas(including gaseous light hydrocarbon and its cracking reaction products, pre-lift gas) and a small amount of catalyst bypass the flow regulating member to enter the reactant riser;

[0041] Step (3): The gaseous light hydrocarbon enters the catalyst dense bed section of the light hydrocarbon diameter expansion reactor through the gaseous light hydrocarbon feed distributor and the gas distribution plate, and after being contacted with the catalyst falling into the catalyst dense bed section, cracking reaction occurs, and the gaseous light hydrocarbon and its cracking reaction products and the catalyst continue to go up and bypass the flow regulating member to enter the reactant riser;

[0042] Step (4): The two streams in step (2) and step (3), i.e. most of the oil gas and a small amount of catalyst in step (2), and the gaseous light hydrocarbon and its cracking reaction products and the catalyst in step (3), enter the separation equipment through the reactant riser for separation, and the obtained gas is discharged through the oil gas outlet pipeline.

[0043] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process of the present application, the process further comprises: the spent catalyst obtained by separation through the separation equipment enters the stripping section, and steam is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas carried by the spent catalyst and make it enter the separation equipment to combine with the reaction products.

[0044] In the above-mentioned light hydrocarbon catalytic cracking process, the upper part of the light hydrocarbon diameter expansion reactor is provided with a flow regulating member, under the influence of the flow regulating member, the gas linear velocity is accelerated, so that the catalyst in the light hydrocarbon diameter expansion reactor can be taken out and enter the upper part of the reactant riser together with the gas, in the reactant riser, due to the decrease of the cross-sectional area of the reactant riser, the gas linear velocity is increased, the gas-solid flow in the reactant riser is fluidized into a fast transport bed, and the above-mentioned two materials pass through the reactant riser into the separation equipment 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 such catalyst is coke generated in the reaction process, which is called spent catalyst, the obtained gas is discharged through the oil gas outlet pipeline, the lower part of the stripping section is connected with a spent catalyst inclined pipe, the spent catalyst can be introduced into the regenerator through the spent catalyst inclined pipe for air coke burning regeneration, then introduced into the catalyst pre-lifting section through the regeneration inclined pipe for recycling, or introduced into the heavy oil reactor for improving its reaction performance.

[0045] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process, the process further comprises: mixing the gas phase light hydrocarbon and water vapor first, and then making the obtained mixture pass through the gas light hydrocarbon feed distributor and the gas distribution plate into the catalyst dense bed section of the light hydrocarbon diameter expansion reactor, for adjusting the catalyst fluidization state and the hydrocarbon partial pressure, so as to strengthen the cracking reaction path of the hydrocarbon, and the amount of water vapor used in the present application is not specifically required, which can be reasonably adjusted according to the actual operation needs on site.

[0046] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process, the gas phase apparent linear velocity of the gas phase light hydrocarbon and its cracking reaction products and water vapor in the light hydrocarbon diameter expansion reactor is maintained at 0.7-1.4 m / s, so as to maintain the turbulent flow state in the light hydrocarbon diameter expansion reactor, which can strengthen the contact between the oil gas and the catalyst.

[0047] As a specific embodiment of the above-mentioned light hydrocarbon catalytic cracking process, the temperature of the high-temperature regenerated catalytic cracking or catalytic cracking catalyst, i.e. the catalyst before contacting with oil, is 660-760℃, the oil gas outlet temperature of the liquid feed riser is 560-650℃, preferably 580-630℃, the temperature of the catalyst dense bed section at the lower part of the light hydrocarbon diameter expansion reactor is 540-630℃, preferably 560-620℃.

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

[0049] As a specific embodiment of the above-mentioned catalytic cracking process of light hydrocarbons of the present application, the liquid light hydrocarbons are introduced into the liquid light hydrocarbon feed and reaction section by means of steam atomization or direct mechanical spraying through liquid light hydrocarbon feed nozzles; preferably, the liquid light hydrocarbon feed nozzles are atomized steam nozzles, which utilize the collision between water vapor and liquid light hydrocarbons inside the nozzles to achieve the atomization of the light hydrocarbons.

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

[0051] As a specific embodiment of the above-mentioned catalytic cracking process of light hydrocarbons of the present application, the gas phase light hydrocarbons (i.e. light hydrocarbons after gasification) include light hydrocarbons with carbon atom number of 3-8, which are rich in olefins, etc., and preferably light hydrocarbons with carbon atom number of 4-6, which are rich in olefins. In some embodiments of the present application, the gas phase light hydrocarbons can be selected from one or a combination of several of ether post-C4 light hydrocarbons, ether post-light gasoline, catalytic light gasoline, coking light gasoline and thermal cracking light gasoline, etc.

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

[0053] As a specific embodiment of the above-mentioned catalytic cracking process of light hydrocarbons of the present application, the process is suitable for all types of catalytic cracking or catalytic cracking catalysts, the active components of which are selected from one, two or three combinations of Y or HY type zeolites with or without rare earth, ultra-stable Y type zeolites with or without rare earth, ZSM-5 series zeolites, high-silicon zeolites with five-membered ring structure prepared by other methods, and amorphous silicon-aluminum catalysts.

[0054] Compared with the prior art, the present application can achieve the following beneficial effects:

[0055] (1) The light hydrocarbon catalytic cracking device provided by the application is a light hydrocarbon catalytic cracking reaction device under non-hydrogen condition in series, which can realize the feeding of two light hydrocarbons, i.e., one light hydrocarbon is gas-phase feeding, and the other light hydrocarbon is liquid-phase feeding and effective contact with the catalyst. The liquid feeding riser is used for processing liquid light hydrocarbon, and the liquid light hydrocarbon can be directly introduced for processing. In the liquid light hydrocarbon feeding section of the liquid feeding riser and the feeding section at the bottom of the reaction section, the liquid light hydrocarbon is contacted with the high-temperature regenerated catalytic cracking or catalytic cracking catalyst after reaction, which is beneficial to realize the cracking reaction of the liquid light hydrocarbon;

[0056] (2) The liquid feeding riser in the light hydrocarbon catalytic cracking device is coupled with the light hydrocarbon diameter-expanding reactor through special design, the catalyst contacted with the liquid light hydrocarbon, high-temperature and still having high activity, can be deposited in the middle and lower part of the light hydrocarbon diameter-expanding reactor, i.e., the catalyst dense bed section, and then contacted with the gasified light hydrocarbon, i.e., the gas-phase light hydrocarbon feeding, and reacted;

[0057] (3) The light hydrocarbon catalytic cracking device has special reactor configuration and connection mode, realizes the controllable flow of the catalyst and oil gas, constructs the reaction environment of the enhanced contact of the two light hydrocarbon feedings with the catalyst, so that the enhanced contact of the light hydrocarbon with the catalyst can be realized, the purpose of making the light hydrocarbon fully react can be achieved, and the specific processing capacity of the device and the processing efficiency of the light hydrocarbon can be improved;

[0058] (4) The inner member is arranged in the upper part of the light hydrocarbon diameter-expanding reactor in the light hydrocarbon catalytic cracking device, which can effectively regulate the controllable flow of the oil gas and catalyst in the light hydrocarbon diameter-expanding reactor and the stability of the gas-solid fluidization. Specifically, the inner member includes two parts: the outlet adjusting section of the liquid feeding riser and the flow regulating member in the light hydrocarbon diameter-expanding reactor. The outlet adjusting section of the liquid feeding riser effectively adjusts the flow direction of the oil gas and catalyst at the outlet of the liquid feeding riser, changes the oil gas flow direction from upward to horizontal and rotates along the axial direction of the riser, forms a cyclone in the upper part of the light hydrocarbon diameter-expanding reactor, and facilitates the reduction of the edge wall effect in the reactor, so that the oil gas and catalyst in the two reactors, i.e., the liquid feeding riser and the light hydrocarbon diameter-expanding reactor, can be fully mixed. The ratio of the diameter of the vertical projection (circle) of the flow regulating member in the light hydrocarbon diameter-expanding reactor to the diameter of the cross section of the light hydrocarbon diameter-expanding reactor is 0.5-0.9:1, which can accelerate the gas linear velocity, so that the catalyst in the light hydrocarbon diameter-expanding reactor can be taken out and enter the upper reaction riser together with the gas, which can effectively improve the stability of the gas-solid fluidization in the light hydrocarbon diameter-expanding reactor.

[0059] (5) The light hydrocarbon catalytic cracking device has multiple operation modes, and product structure can be flexibly adjusted. For example, the light hydrocarbon catalytic cracking device can be used alone, i.e. the light hydrocarbon catalytic cracking device is used alone to form a light hydrocarbon catalytic cracking reaction-regeneration system with a catalyst regeneration system, in which case the regeneration system needs to take measures such as supplemental combustion to maintain the heat balance of the device, or the light hydrocarbon catalytic cracking device can be combined with a heavy oil catalytic cracking / catalytic cracking reactor to form a double-reactor system, in which the two reactors share a catalyst regeneration system, and the oil gas after reaction can be merged into an oil gas separation system or can enter respective oil gas separation systems.

[0060] (6) The light hydrocarbon catalytic cracking device and process can recycle light hydrocarbons, gasoline or diesel oil and the like rich in C4-C8 olefins in the whole plant; product quality can be improved, and the diesel-gasoline ratio can be controlled; and the yield of cracked gas in the whole plant can be further increased, i.e. the yield of raw materials required by light hydrocarbon processing devices such as MTBE, light gasoline etherification and polypropylene can be increased, so that the product structure of the whole plant can be controlled. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0062] Figure 1 The structure schematic diagram of the light hydrocarbon catalytic cracking device provided for the embodiment 1 of the present application.

[0063] Figure 2 The cross-sectional schematic diagram of the outlet adjustment section in the light hydrocarbon catalytic cracking device provided for the embodiment 1 of the present application.

[0064] Figure 3 The structure schematic diagram of the light hydrocarbon catalytic cracking riser reactor used in the comparative example 1 to the comparative example 3.

[0065] Main drawing number explanation:

[0066] 1, catalyst pre-lifting section, 2, liquid light hydrocarbon feed and reaction section, 3, outlet adjustment section, 4, light hydrocarbon diameter expansion reactor, 5, reactant riser, 6, light hydrocarbon settler, 7, stripping section, 8, oil gas outlet pipeline, 9, pre-lifting gas inlet, 10, regenerated catalyst inclined pipe, 11, liquid light hydrocarbon, 12, gaseous light hydrocarbon feed, 13, gaseous light hydrocarbon feed distributor, 14, gas distribution plate, 15, flow regulating member, 16, oil gas outlet, 17, spent catalyst inclined pipe;

[0067] 31, pre-lifting section, 32, riser reaction section, 33, gaseous light hydrocarbon feed ring pipe. Detailed Implementation

[0068] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. 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 explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0069] In this invention, the terms "upper," "lower," "inner," "outer," "middle," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0070] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0071] Furthermore, the terms "set up" and "connected" should be interpreted broadly. For example, "connected" can refer to 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 refer to the internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] The "range" disclosed in this invention is given in the form of a lower limit and an 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 and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0073] In the present application, unless otherwise specified, the numerical range "a-b" represents a shorthand notation for any real combination of numbers between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" represents that all real numbers between "0-5" have been listed in the present application, and "0-5" is just a shorthand notation for these numerical combinations.

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

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

[0076] In the present application, unless otherwise specified, all steps mentioned in the present application can be performed in sequence or randomly, but preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method further comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0077] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in combination with the accompanying tables, drawings and examples. The following described examples are part of the examples of the present application, but not all the examples, which are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the examples in the present application, all other examples obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0078] Device embodiment

[0079] Example 1

[0080] The present embodiment provides a light hydrocarbon catalytic cracking device, the structural schematic diagram of which is shown in Figure 1 As can be seen from Figure 1 The light hydrocarbon catalytic cracking device comprises:

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

[0082] The liquid feed riser is arranged at the lower end of the light hydrocarbon enlarged-diameter reactor, one end of the liquid feed riser penetrates into the shell of the bottom of the light hydrocarbon enlarged-diameter reactor 4 to enter the light hydrocarbon enlarged-diameter reactor 4, and both are coaxially arranged, the lower part of the annular space formed by the liquid feed riser and the shell of the light hydrocarbon enlarged-diameter reactor 4 is sequentially provided from bottom to top with a gaseous light hydrocarbon feed distributor 13, a gas distribution plate 14 and a catalyst dense bed section (not shown in the figure), and a flow regulating member 15 is arranged near the top of the light hydrocarbon enlarged-diameter reactor 4; the top of the light hydrocarbon enlarged-diameter reactor 4 is communicated with the bottom of the reactant riser 5, one end of the reactant riser 5 penetrates into the shell of the bottom of the light hydrocarbon settler 6 to enter the light hydrocarbon settler 6, and is communicated with a separation device in the light hydrocarbon settler 6, the gas outlet of the separation device is communicated with the oil and gas outlet pipeline 8 through a gas collecting device (not shown in the figure);

[0083] The liquid feed riser sequentially comprises a catalyst pre-lifting section 1, a liquid light hydrocarbon feed and reaction section 2 and an outlet adjusting section 3 which are communicated in sequence, the liquid light hydrocarbon feed and reaction section 2 and the outlet adjusting section 3 are integrally arranged in this embodiment, and the outlet adjusting section 3 and part of the liquid light hydrocarbon feed and reaction section 2 are located in the light hydrocarbon enlarged-diameter reactor 4; the bottom of the catalyst pre-lifting section 1 is provided with a pre-lifting gas inlet 9, the middle and lower part of the catalyst pre-lifting section 1 is communicated with a regeneration inclined pipe 10; the bottom of the liquid light hydrocarbon feed and reaction section 2 is provided with a liquid light hydrocarbon feed nozzle (not shown in the figure), the upper part of the side wall of the outlet adjusting section 3 is provided with an oil and gas outlet 16, and the top of the outlet adjusting section 3 is connected with the flow regulating member 15.

[0084] The liquid light hydrocarbon feed nozzle is arranged symmetrically along the same height around the liquid light hydrocarbon feed and reaction section 2, a sectional view of the outlet adjusting section 3 is shown in Figure 2 The oil and gas outlet 16 is arranged at the upper part of the side wall of the outlet adjusting section 3 and near 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 with the liquid light hydrocarbon feed and reaction section 2 through a moderate expansion frustum, the bottom of the light hydrocarbon enlarged-diameter reactor 4 is in the shape of an inverted dome, the middle part is in the shape of a cylinder, the top is in the shape of a dome or a frustum, the gaseous light hydrocarbon feed distributor 13 is a ring-shaped feed pipe in the shape of multiple concentric circles with multiple gaseous light hydrocarbon feed nozzles, the flow regulating member 15 is a conical cylinder, the vertical projection of which is circular, the shell of the reactant riser 5 and the light hydrocarbon settler 6 forms 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 further connected with a green catalyst inclined pipe 17, the separation device is a 1-3 stage cyclone separator, and the cyclone separator is a volute type or straight-cut type cyclone separator.

[0085] The operation process of the light hydrocarbon catalytic cracking device provided by the embodiment comprises:

[0086] The pre-lift gas enters the pre-lift gas inlet 9 arranged at the bottom of the catalyst pre-lift section 1, contacts the high-temperature regenerated catalytic cracking or catalytic cracking catalyst from the regeneration inclined pipe 10 connected to the catalyst pre-lift section 1, and fluidizes the catalyst to flow upwards along the catalyst pre-lift section 1; the liquid light hydrocarbon feed and reaction section 2 is moderately expanded, 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 the fluidized catalyst rising from the lower part, realizes the gasification of the liquid light hydrocarbon and the cracking reaction thereof, and the gaseous light hydrocarbon and the reaction products thereof, the pre-lift gas and the catalyst continue to flow upwards 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 sprayed out from the side channel of the outlet adjustment section 3 to enter the upper part of the light hydrocarbon expanded reactor 4; due to the increase of the horizontal cross section of the light hydrocarbon expanded reactor 4, the linear velocity of the oil gas flow is greatly reduced, causing most of the catalyst to fall into the lower part of the light hydrocarbon expanded reactor 4; and most of the oil gas and a small amount of catalyst, denoted as material 1, bypass the flow regulating member 15 in the light hydrocarbon expanded reactor 4 to enter the upper reaction material riser 5.

[0087] The gaseous light hydrocarbon feed 12 enters the bottom of the light hydrocarbon expanded reactor 4 through the gaseous light hydrocarbon feed distributor 13, and then enters the catalyst dense bed section of the light hydrocarbon expanded reactor 4 through the holes of the upper gas distribution plate 14, so as to realize the high-efficiency contact between the light hydrocarbon and the catalyst and realize the reaction of the light hydrocarbon. Due to the influence of the flow regulating member 15 at the upper part of the catalyst dense bed section, the linear velocity of the gas is accelerated, so that the gaseous light hydrocarbon and the cracking reaction products thereof can carry the catalyst in the catalyst dense bed section out of the catalyst dense bed section and enter the upper reaction material riser 5 together with the gas, and the gaseous light hydrocarbon, the cracking reaction products thereof and the catalyst are denoted as material 2.

[0088] The material 1 and the material 2 are transported through the reaction material riser 5 and enter the separation equipment at the upper part of the light hydrocarbon settler 6 to separate the gas from the catalyst; under the action of the separation equipment, the gas enters the gas collection equipment at the top of the light hydrocarbon settler, is discharged from the oil gas outlet pipeline at the top, and the catalyst is discharged from the lower part of the separation equipment to enter the stripping section 7 of the light hydrocarbon settler 6; the surface of such catalyst is coke generated in the reaction process, which is called spent catalyst. In the stripping section 7, the water vapor injected into the stripping section 7 through the steam distributor can strip the volatile hydrocarbon gas entrained on the spent catalyst and make it enter the separation equipment to combine with the gaseous reaction products. The lower part of the stripping section 7 is connected with the spent catalyst inclined pipe 17, the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe 17 to be regenerated by air coking, and then is introduced into the catalyst pre-lift section 1 through the regeneration inclined pipe 10 for recycling, or is introduced into the heavy oil reactor to improve the reaction performance thereof.

[0089] Process embodiment

[0090] Embodiment 2

[0091] The embodiment provides a process for producing low-carbon olefins by catalytic cracking of light hydrocarbons, which is realized by using the light hydrocarbon catalytic cracking device provided in embodiment 1. In the light hydrocarbon catalytic cracking device, the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon nozzle is arranged in a slightly downward inclined manner, the included angle between the axial direction and the horizontal plane is 30°, the shape of the oil gas outlet 16 is oval, the sum of the areas of the oil gas outlet is 70% of the cross-sectional area of the outlet adjusting section, and the oil gas outlet 16 is connected with symmetrically arranged oval side channels. The side channels are arranged in the same horizontal plane, and the axis of the side channel and the radial extension line of the liquid feed riser form an angle of 30°. The lengths of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feeding and reaction section 2 are 5 m and 15 m respectively, and the inner diameters are 0.5 m and 0.6 m respectively, that is, the ratio of the inner diameters of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feeding and reaction section 2 is 1:1.2. The height of the light hydrocarbon diameter expansion reactor 4 is 3 m, and the inner diameter is 1.9 m. The gas distribution plate 14 is uniformly provided with a plurality of holes, and the total opening rate is 6%. The hole diameter of the hole is 5 mm. The hole is provided with a ceramic wear-resistant lining. The flow regulating member 15 is a conical cylinder, and the vertical projection is a circle. The diameter of the circle is 1.6 m, that is, the ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon diameter expansion reactor 4 is 0.84:1. The length of the reactant riser 5 is 18 m, and the inner diameter is 0.6 m.

[0092] The process comprises the following specific steps:

[0093] The pre-lifting gas (water vapor or dry gas) and the high-temperature regenerated catalytic cracking or catalytic cracking catalyst are respectively introduced into the catalyst pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe to contact and fluidize. The fluidized catalyst is lifted with the pre-lifting gas and enters the liquid light hydrocarbon feeding and reaction section.

[0094] The liquid light hydrocarbon is sprayed into the bottom of the liquid light hydrocarbon feeding and reaction section through the liquid light hydrocarbon nozzle, and is contacted with the fluidized catalyst to realize the gasification and cracking reaction of the liquid light hydrocarbon. The gaseous light hydrocarbon and its cracking reaction products, the pre-lifting gas and the catalyst flow upwards along the liquid light hydrocarbon feeding and reaction section, enter the outlet adjusting section, and are sprayed from the oil gas outlet into the upper part of the light hydrocarbon diameter expansion reactor in the horizontal direction. Due to the increase of the horizontal cross section of the light hydrocarbon diameter expansion reactor, the linear velocity of the oil gas flow is greatly reduced, causing most of the catalyst to fall into the catalyst dense phase bed section in the lower part of the light hydrocarbon diameter expansion reactor 4, and most of the oil gas and a small amount of catalyst, denoted as material 1, bypass the flow regulating member and enter the reactant riser.

[0095] The gas phase light hydrocarbon enters the catalyst dense bed section of the light hydrocarbon up-sizing reactor through the gas light hydrocarbon feed distributor and the gas distribution plate, and has a cracking reaction with the catalyst falling into the catalyst dense bed section. The gas phase light hydrocarbon and the cracking reaction products and catalyst, denoted as material 2, continue to go up and bypass the rectifying member to enter the reactant riser; wherein the light hydrocarbon up-sizing reactor is in a turbulent flow state;

[0096] The material 1 and the material 2 enter the separation device through the reactant riser for separation, and the obtained gas is discharged through the oil gas outlet pipeline;

[0097] The spent catalyst obtained by separation through the separation device enters the stripping section, steam is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas carried by the spent catalyst and enter the separation device to combine with the gas phase reaction products, and the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe for air coke burning regeneration, and finally introduced into the catalyst pre-lifting section through the regeneration inclined pipe for recycling.

[0098] The property parameters of the liquid light hydrocarbon, the gas phase light hydrocarbon (ether after C4) and the catalyst used in the embodiment are shown in Tables 1-3 respectively, and the operating conditions, product distribution and main properties of the products in the embodiment are shown in Table 4. The embodiment adopts moderate severity operating conditions.

[0099] Example 3

[0100] The embodiment provides a process for producing low carbon olefins by light hydrocarbon catalytic cracking, which is only different from the embodiment 2 in that the operating conditions are different. The embodiment adopts higher severity operating conditions, and the operating conditions, product distribution and main properties of the products are also listed in Table 4.

[0101] Example 4

[0102] The embodiment provides a process for producing low-carbon olefins by catalytic cracking of light hydrocarbons, which is realized by using the light hydrocarbon catalytic cracking device provided in the embodiment 1. In the light hydrocarbon catalytic cracking device, the axial direction of the liquid light hydrocarbon sprayed by the liquid light hydrocarbon nozzle is arranged in a slightly upward inclined manner, the included angle between the axial direction and the horizontal plane is 45°, the shape of the oil gas outlet 16 is a rectangle, the sum of the areas of the oil gas outlet is 400% of the cross-sectional area of the outlet adjusting section, and the oil gas outlet 16 is connected with three center-symmetrically arranged rectangular side channels, the side channels are arranged on the same horizontal plane, the axis of the side channel and the radial extension line of the liquid feed lifting pipe form an angle of 60°, the lengths of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feeding and reaction section 2 are 3 m and 16 m respectively, and the inner diameters are 0.3 m and 0.48 m respectively, that is, the ratio of the inner diameters of the catalyst pre-lifting section 1 and the liquid light hydrocarbon feeding and reaction section 2 is 1:1.6, the height of the light hydrocarbon diameter expansion reactor 4 is 3.5 m, the inner diameter is 2.1 m, the gas distribution plate 14 is uniformly provided with a plurality of holes, the total opening rate is 25%, the hole diameter of the hole is 60 mm, the hole is provided with a ceramic wear-resistant lining, the flow regulating member 15 is a conical cylinder, the vertical projection is a circle, the diameter of the circle is 1.3 m, that is, the ratio of the diameter of the circle to the diameter of the cross section of the light hydrocarbon diameter expansion reactor 4 is 0.62:1, and the length of the reactant lifting pipe 5 is 16 m and the inner diameter is 0.6 m.

[0103] The process comprises the following specific steps:

[0104] The pre-lifting gas (water vapor or dry gas) and the high-temperature regenerated catalytic cracking or catalytic cracking catalyst are respectively introduced into the catalyst pre-lifting section through the pre-lifting gas inlet and the regeneration inclined pipe to contact and fluidize, and the fluidized catalyst is lifted into the liquid light hydrocarbon feeding and reaction section along with the pre-lifting gas.

[0105] The liquid light hydrocarbon is sprayed into the bottom of the liquid light hydrocarbon feeding and reaction section through the liquid light hydrocarbon nozzle, and is contacted with the fluidized catalyst to realize the gasification and cracking reaction of the liquid light hydrocarbon; the gaseous light hydrocarbon and the cracking reaction products, the pre-lifting gas and the catalyst are upwardly introduced into the outlet adjusting section along the liquid light hydrocarbon feeding and reaction section, and are sprayed out of the oil gas outlet into the upper part of the light hydrocarbon diameter expansion reactor in the horizontal direction, due to the increase of the horizontal cross section of the light hydrocarbon diameter expansion reactor, the oil gas flow linear velocity is greatly reduced, most of the catalyst falls into the catalyst dense phase bed section in the lower part of the light hydrocarbon diameter expansion reactor 4, and most of the oil gas and a small amount of catalyst, denoted as material 1, bypasses the flow regulating member and enters the reactant lifting pipe;

[0106] The gas phase light hydrocarbon enters the catalyst dense bed section of the light hydrocarbon up-sized reactor through the gas light hydrocarbon feed distributor and the gas distribution plate, and cracks after contacting with the catalyst falling into the catalyst dense bed section. The gas phase light hydrocarbon, the cracking product thereof and the catalyst, denoted as material 2, continue to go up and bypass the rectifying member to enter the reactant riser. The light hydrocarbon up-sized reactor is in a turbulent flow state;

[0107] The material 1 and the material 2 enter the separation device through the reactant riser to be separated, and the obtained gas is discharged through the oil gas outlet pipeline;

[0108] The spent catalyst obtained by separation through the separation device enters the stripping section, steam is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas entrained by the spent catalyst and enter the separation device to combine with the gas phase reaction product, and then the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe for air coke burning regeneration, and finally introduced into the catalyst pre-lifting section through the regeneration inclined pipe for recycling.

[0109] The property parameters of the liquid light hydrocarbon, the gas phase light hydrocarbon (ether after C4) and the catalyst used in the embodiment are also the same as those in embodiment 1, and are shown in tables 1-3. The operating conditions, product distribution and main properties of the products in the embodiment are also listed in table 4. The operating conditions in the embodiment are lower in severity.

[0110] Comparative example 1

[0111] The comparative example provides a process for producing low carbon olefins by catalytic cracking of gas phase light hydrocarbons, which is realized by using a light hydrocarbon catalytic cracking riser reactor as shown in Figure 3 The light hydrocarbon catalytic cracking riser reactor includes a pre-lifting section 31, a riser reaction section 32 and a light hydrocarbon settler 6. The pre-lifting section 31 is connected with the riser reaction section 32 through a moderately up-sized circular truncated cone. The lengths of the pre-lifting section 31 and the riser reaction section 32 are 5 m and 36 m respectively, and the inner diameters thereof are 0.5 m and 0.6 m respectively. The bottom of the pre-lifting section 31 is provided with a pre-lifting gas inlet 9, and the middle and lower part of the pre-lifting section 31 is communicated with a regeneration inclined pipe 10. The top of the riser reaction section 32 penetrates into the shell of the bottom of the light hydrocarbon settler 6 to enter the light hydrocarbon settler 6, and is communicated with a separation device in the light hydrocarbon settler 6. The gas outlet of the separation device is communicated with an oil gas outlet pipeline 8 through a gas collecting device (not shown in the figure). The shell of the riser reaction section 32 and the light hydrocarbon settler 6 forms an annular space. The inner and lower part of the annular space is a stripping section 7, which is provided with a steam distributor (not shown in the figure). The lower part of the stripping section 7 is also connected with a spent catalyst inclined pipe 17. A gas phase light hydrocarbon feed ring pipe 33 is arranged at the bottom of the riser reaction section 32.

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

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

[0114] The pre-lift gas (water vapor or dry gas) and the catalytic cracking or catalytic cracking catalyst after high-temperature regeneration are respectively introduced into the pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe to contact fluidization, and the fluidized catalyst is lifted into the riser reaction section along with the pre-lift gas;

[0115] The gas-phase light hydrocarbons are introduced into the riser reaction section through the gas-phase light hydrocarbon feed ring pipe, and are contacted with the fluidized catalyst to realize the cracking reaction of the gas-phase light hydrocarbons; the gas-phase light hydrocarbons and their cracking reaction products, the pre-lift gas and the catalyst are upward along the riser reaction section and enter the separation device for separation, and the obtained gas is discharged through the oil and gas outlet pipeline;

[0116] The spent catalyst obtained by separation through the separation device is introduced into the stripping section, steam is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas entrained by the spent catalyst and introduce it into the separation device to combine with the gaseous reaction products, and finally the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe for air coke-burning regeneration, and then is introduced into the catalyst pre-lift section through the regeneration inclined pipe for recycling.

[0117] The properties and parameters of the gas-phase light hydrocarbons (ether after C4) and the catalyst used in the present comparative example are shown in Tables 2-3, the operating conditions, product distribution and main properties of the products in the comparative example are listed in Table 4, and the light hydrocarbon processing amount is recorded as a reference M kg / h.

[0118] Comparative Example 2

[0119] The present comparative example provides a process for producing low-carbon olefins by catalytic cracking of liquid light hydrocarbons, which is realized by using a light hydrocarbon catalytic cracking riser reactor. The difference between the light hydrocarbon catalytic cracking riser reactor used in the present comparative example and the light hydrocarbon catalytic cracking riser reactor used in Comparative Example 1 is that the gas-phase light hydrocarbon feed ring pipe 33 is not arranged at the bottom of the riser reaction section 32, but a liquid light hydrocarbon feed nozzle is arranged 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 included angle between the axial direction of the liquid light hydrocarbon discharged from 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 includes the following specific steps:

[0121] The pre-lift gas (water vapor or dry gas) and the high-temperature regenerated catalytic cracking or catalytic cracking catalyst are respectively introduced into the pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe to contact fluidization, and the fluidized catalyst is lifted into the riser reaction section along with the pre-lift gas;

[0122] The liquid light hydrocarbon is introduced into the riser reaction section through the liquid light hydrocarbon feed nozzle and is contacted with the fluidized catalyst to realize the gasification and cracking reaction of the liquid light hydrocarbon; the gaseous light hydrocarbon and the cracking reaction products, the pre-lift gas and the catalyst are upwardly introduced into the separation device along the riser reaction section and are separated, and the obtained gas is discharged through the oil and gas outlet pipeline;

[0123] The spent catalyst obtained by separation is introduced into the stripping section, steam is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas carried by the spent catalyst and introduce it into the separation device to combine with the gaseous reaction products, and the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe for air coke-burning regeneration, and finally is introduced into the catalyst pre-lift section through the regeneration inclined pipe for recycling.

[0124] The properties of the liquid light hydrocarbon and the catalyst used in the present 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, and the light hydrocarbon processing amount is denoted as a reference M kg / h.

[0125] Comparative Example 3

[0126] The present comparative example provides a process for producing low-carbon olefins from liquid light hydrocarbons and gaseous light hydrocarbons by catalytic cracking, which is realized by using a light hydrocarbon catalytic cracking riser reactor. The difference between the light hydrocarbon catalytic cracking riser reactor used in the present comparative example and the light hydrocarbon catalytic cracking riser reactor used in Comparative Example 1 is that a gaseous light hydrocarbon feed ring pipe 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 4 m from the bottom of the riser reaction section 32, and the liquid light hydrocarbon feed nozzle is arranged slightly downward (the inclination angle is 30°, i.e. the included angle between the axial direction of the liquid light hydrocarbon discharged from the liquid light hydrocarbon feed nozzle and the horizontal plane is 30°);

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

[0128] The pre-lift gas (water vapor or dry gas) and the high-temperature regenerated catalytic cracking or catalytic cracking catalyst are respectively introduced into the pre-lift section through the pre-lift gas inlet and the regeneration inclined pipe to contact fluidization, and the fluidized catalyst is lifted into the riser reaction section along with the pre-lift gas;

[0129] The gas phase light hydrocarbon enters the riser reaction section through the gas phase light hydrocarbon feed ring, and is contacted with the fluidized catalyst to realize the cracking reaction of the gas phase light hydrocarbon; the gas phase light hydrocarbon and its cracking reaction products, the pre-lifting gas and the catalyst go up along the riser reaction section, and are contacted with the liquid light hydrocarbon entering the riser reaction section through the liquid light hydrocarbon feed nozzle to realize the gasification of the liquid light hydrocarbon and its cracking reaction; the gas phase light hydrocarbon and its cracking reaction products, the pre-lifting gas and the catalyst continue to go up along the riser reaction section and enter the separation device for separation, and the obtained gas is discharged through the oil and gas outlet pipeline;

[0130] The spent catalyst obtained by separation is introduced into the stripping section, water vapor is injected into the stripping section through the steam distributor to strip the volatile hydrocarbon gas carried by the spent catalyst and combine with the gaseous reaction products in the separation device, and then the spent catalyst is introduced into the regenerator through the spent catalyst inclined pipe for air coke-burning regeneration, and finally is introduced into the catalyst pre-lifting section through the regenerated inclined pipe for recycling.

[0131] The property parameters of the liquid light hydrocarbon, the gas phase light hydrocarbon (ether after C4) and the catalyst used in the present comparative example are shown in Tables 1-3 respectively, and 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 hydrocarbon

[0133] Component Light gasoline Cracked gasoline properties Density (20°C), kg / m 3 ]] 698 Hydrocarbon group composition, v% Saturates 25 Olefins 68 Aromatics 7 Distillation range, wt% ~ °C Initial boiling point 35 10％ 52 50％ 69 90％ 85 EBP (end boiling point) 99

[0134] Table 2 Properties of gas phase light hydrocarbon

[0135] Component Light gasoline Cracked gasoline properties Density (20°C), kg / m 3 ]] 698 Hydrocarbon group composition, v% Saturates 25 Olefins 68 Aromatics 7 Distillation range, wt% ~ °C Initial boiling point 35 10％ 52 50％ 69 90％ 85 EBP (end boiling point) 99

[0136] Table 3 Properties of catalyst

[0137] Main catalyst Catalyst Zeolite type ZSM-5 as main Chemical composition, wt% Alumina 52.1 Sodium oxide 0.15 Screening composition, wt% 0-40 μm 25.54 40-80 μm 48.05 > 110 μm 26.41 Specific surface area / m 2 ·g -1 ]]> 210 Deposition density / g-cm -3 ]] 0.79 Apparent density / g-cm -3 ]] 0.75 Micro-activity, % 58 Screening composition, wt% 0.28

[0138] The catalyst in Table 3 is produced by Lanzhou Catalyst Factory of PetroChina.

[0139] Table 4 Operating conditions and product distribution

[0140]

[0141] In summary, the process for producing low-carbon olefins by catalytic cracking of light hydrocarbons provided by the embodiment 2 of the present application is realized by using the light hydrocarbon catalytic cracking device provided by the embodiment 1, the processes provided by the comparative examples 1-3 are realized by using the existing light hydrocarbon catalytic cracking riser, and the comparative example 1 only uses gaseous light hydrocarbon feed, the comparative example 2 only uses liquid light hydrocarbon feed, and the comparative example 3 uses combined feed of gaseous light hydrocarbon and liquid light hydrocarbon. As can be seen from Table 4, the embodiment 2 of the present application and the comparative example 3 are both two light hydrocarbon feeds, compared with each other, the light hydrocarbon processing capacity can be significantly improved by using the light hydrocarbon catalytic cracking device, and the yield of liquefied gas and propylene can be greatly improved, and the content of aromatic hydrocarbons in gasoline can also be improved, which all show that the light hydrocarbon catalytic cracking device and process provided by the present application can significantly improve the light hydrocarbon processing capacity and light hydrocarbon cracking depth, and is an excellent light hydrocarbon catalytic cracking reactor.

[0142] As can be seen from Table 4, the embodiment 3 of the present application uses high severity operation, can achieve higher yield of liquefied gas and propylene, and the content of aromatic hydrocarbons in gasoline is very high and can be further extracted; and the embodiment 4 of the present application is moderately modified in device parameters, investigates the parameters of the relative boundary of the device, and operates at a lower severity, can moderately produce more liquefied gas and propylene, and the content of olefins in gasoline also has a large decrease. As can be seen from the three embodiments, the related parameters of the device provided by the present application can be changed in a large range, the range of process operation conditions is wide, and is suitable for moderately producing more liquefied gas, producing more liquefied gas and maximizing the production of liquefied gas.

[0143] The above is only a specific embodiment of the present application, which cannot limit the range of the present application, so the replacement of equivalent components or equivalent changes and modifications made within the scope of the present application should still belong to the scope of the present application. In addition, the technical features in the present application can be freely combined with each other, between technical features, between technical features and technical inventions, and between technical inventions.

Claims

1. A light hydrocarbon catalytic cracking device, characterized in that, The light hydrocarbon catalytic cracking unit includes a liquid feed riser, a light hydrocarbon expansion reactor, a reactant riser, and a light hydrocarbon settling device. The liquid feed riser is located at the lower end of the light hydrocarbon expansion reactor. One end of the liquid feed riser penetrates the shell at the bottom of the light hydrocarbon expansion reactor and enters the reactor. The two are arranged coaxially. The lower part of the annular space formed by the liquid feed riser 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 from bottom to top. The upper part of the light hydrocarbon expansion reactor is provided with a flow rectifying component. The top of the light hydrocarbon expansion reactor is connected to the bottom of the reactant riser. The top of the reactant riser penetrates the shell at the bottom of the light hydrocarbon settling tank and enters the light hydrocarbon settling tank. It is connected to the separation equipment inside the light hydrocarbon settling tank. The gas outlet of the separation equipment is connected to an oil and gas outlet pipeline. The liquid feed riser includes, from bottom to top, a catalyst pre-lifting section, a liquid light hydrocarbon feed and reaction section, and an outlet adjustment section connected in sequence. The bottom of the catalyst pre-lifting section is provided with a pre-lifting gas inlet, and the middle and lower part of the catalyst pre-lifting section is connected to the regeneration inclined pipe. The bottom of the liquid light hydrocarbon feed and reaction section is provided with a liquid light hydrocarbon feed nozzle. The upper part of the side wall of the outlet adjustment section is provided with an oil and gas outlet, and the top of the outlet adjustment section is connected to the rectifier component.

2. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that, The liquid light hydrocarbon feed nozzles are symmetrically arranged at the same height around the bottom of the liquid light hydrocarbon feed and reaction section. The axial direction of the liquid light hydrocarbons ejected from the feed nozzles is upward or downward, and the angle between them 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 riser is located on the upper part of the side wall of the outlet adjustment section and near the top. 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.

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

5. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that, 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.

6. The light hydrocarbon catalytic cracking device according to claim 1, characterized in that, The bottom of the light hydrocarbon expansion reactor is inverted dome-shaped, the middle is cylindrical, and the top is dome-shaped or frustum-shaped.

7. The light hydrocarbon catalytic cracking apparatus according to claim 1 or 6, characterized in that, The gaseous light hydrocarbon feed distributor is a multi-layered concentric annular feed pipe with multiple gaseous light hydrocarbon feed nozzles, or a branched distribution pipe with multiple gaseous light hydrocarbon feed nozzles.

8. The light hydrocarbon catalytic cracking apparatus according to claim 1 or 6, characterized in that, The gas distribution plate is uniformly provided with multiple channels, with a total open area ratio of 5%-50% and a channel diameter of 5-60mm.

9. The light hydrocarbon catalytic cracking apparatus 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. Its vertical projection is circular, and 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 settling tank form an annular space, and the lower part of the annular space is a stripping section, which is equipped with a steam distributor.

11. The light hydrocarbon catalytic cracking apparatus according to claim 10, characterized in that, The lower part of the stripping section is also connected to an inclined tube for the generation of catalyst.

12. A light hydrocarbon catalytic cracking process, characterized in that, The light hydrocarbon catalytic cracking process is implemented using the light hydrocarbon catalytic cracking device according to any one of claims 1-11, and includes the following steps: Step (1): The pre-lift gas and the catalytic cracking or catalytic pyrolysis catalyst after high temperature regeneration enter the catalyst pre-lift section for contact fluidization through the pre-lift gas inlet and the regeneration inclined tube, respectively. The fluidized catalyst enters the liquid light hydrocarbon feed and reaction section as the pre-lift gas lifts it. Step (2): Liquid light hydrocarbons are injected into the bottom of the liquid light hydrocarbon feed and reaction section through the liquid light hydrocarbon feed nozzle and brought into contact with the fluidized catalyst to realize the gasification and cracking reaction of liquid light hydrocarbons; gaseous light hydrocarbons and their cracking reaction products, pre-lift gas and catalysts move upward along the liquid light hydrocarbon feed and reaction section, enter the outlet adjustment section, and are sprayed out from the oil and gas outlet into the upper part of the light hydrocarbon expansion reactor in the horizontal direction, and most of the catalyst falls into the catalyst dense phase bed section, while most of the oil and gas and a small amount of catalyst bypass the rectification component and enter the reactant riser pipe; Step (3): The gaseous light hydrocarbons enter the catalyst dense phase bed section of the light hydrocarbon expansion reactor through the gas light hydrocarbon feed distributor and gas distribution plate and undergo a cracking reaction after contacting the catalyst that falls into the catalyst dense phase bed section. The gaseous light hydrocarbons and their cracking reaction products and catalyst continue to rise and bypass the rectifier to enter the reactant riser. Step (4): The two materials in Step (2) and Step (3), namely most of the oil and gas and a small amount of catalyst in Step (2), the gaseous light hydrocarbons and their cracking reaction products and catalyst in Step (3), enter the separation equipment through the reactant riser for separation, and the resulting gas is discharged through the oil and gas outlet pipeline.

13. The light hydrocarbon catalytic cracking process according to claim 12, characterized in that, The reactant riser and the shell of the light hydrocarbon settling tank form an annular space. The lower part of the annular space is a stripping section, which is equipped with a steam distributor. The process also includes: introducing the catalyst to be generated by separation through the separation equipment into the stripping section, and injecting steam into the stripping section through the steam distributor to strip out the volatile hydrocarbon gas entrained in the catalyst and allow it to flow into the reaction products.

14. The light hydrocarbon catalytic cracking process according to claim 12 or 13, characterized in that, The process also includes: First, gaseous light hydrocarbons and water vapor are mixed, and then the resulting mixture is fed into the dense phase catalyst bed section of the light hydrocarbon expansion reactor through a gaseous light hydrocarbon feed distributor and a gas distribution plate.

15. The light hydrocarbon catalytic cracking process according to claim 14, characterized in that, The process further includes maintaining the apparent linear velocity of gaseous light hydrocarbons, their cracking reaction products, and water vapor in the light hydrocarbon expansion reactor at 0.7-1.4 m / s to maintain a turbulent state within the light hydrocarbon expansion reactor.

16. The light hydrocarbon catalytic cracking process according to claim 12 or 13, characterized in that, The temperature of the catalytic cracking or catalytic pyrolysis catalyst after high-temperature regeneration is 660-760℃, the oil and gas outlet temperature of the liquid feed riser is 560-650℃, and the temperature of the dense phase catalyst bed section at the bottom of the light hydrocarbon expansion reactor is 540-630℃.

17. The light hydrocarbon catalytic cracking process according to claim 16, characterized in that, The apparent residence time of oil and gas in the liquid feed riser is 0.8-2 s, the apparent residence time of oil and gas in the light hydrocarbon expansion reactor is 1.5-10 s, and the apparent residence time of oil and gas in the reactant riser is 0.5-5 s.

18. The light hydrocarbon catalytic cracking process according to claim 12 or 13, characterized in that, The liquid light hydrocarbons include one or a combination of olefin-rich gasoline and diesel.

19. The light hydrocarbon catalytic cracking process according to claim 18, characterized in that, The olefin-rich gasoline includes light hydrocarbons with 4-8 carbon atoms that are either not rich in or rich in olefins.

20. The light hydrocarbon catalytic cracking process according to claim 12 or 13, characterized in that, The gaseous light hydrocarbons include light hydrocarbons with 3-8 carbon atoms that are rich in olefins.

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