Light-hydrocarbon catalytic cracking device and method

Abstract

Provided in the present invention are a light-hydrocarbon catalytic cracking device and method. The device comprises a liquid hydrocarbon treatment pipe, a crude separation apparatus, a gaseous hydrocarbon diameter-expanded reactor, a reaction product riser, and a reaction product post-treatment unit. The tail end of the liquid hydrocarbon treatment pipe is provided with a swirling nozzle. The crude separation apparatus is a variable-diameter pipe, in which the diameter of a top pipe section < the diameter of a bottom pipe section < the diameter of a middle pipe section. The crude separation apparatus is arranged in the gaseous hydrocarbon diameter-expanded reactor, wherein the bottom end of the crude separation apparatus is located at a middle pipe section of the gaseous hydrocarbon diameter-expanded reactor and the top end of the crude separation apparatus is located at the top end of the gaseous hydrocarbon diameter-expanded reactor or at the head of the reaction product riser. The tail end of the liquid hydrocarbon treatment pipe extends into the gaseous hydrocarbon diameter-expanded reactor from an opening at the bottom end of the gaseous hydrocarbon diameter-expanded reactor and then penetrates into the crude separation apparatus from the bottom end of the crude separation apparatus, and is located in the middle pipe section of the crude separation apparatus. The ratio of the inner diameter of the gaseous hydrocarbon diameter-expanded reactor, the outer diameter of the middle pipe section of the crude separation apparatus and the outer diameter of the bottom pipe section of the crude separation apparatus is 1:0.4-0.8:0.15-0.3.

Description

Light hydrocarbon catalytic cracking apparatus and method

[0001] Cross-reference information

[0002] The present application claims priority to the Chinese patent application No. 202411052751.8, filed on August 01, 2024, and entitled "Light hydrocarbon catalytic cracking apparatus and method", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to a light hydrocarbon catalytic cracking apparatus and method suitable for catalytic cracking of petroleum hydrocarbons under non-hydrogen conditions. BACKGROUND

[0004] In the early stage, petroleum hydrocarbon catalytic cracking was carried out using a dense phase bed reactor with aluminum silicate beads as catalyst. With the emergence of high-activity and high-selectivity zeolite catalysts, the reaction rate of petroleum hydrocarbons with catalysts was greatly accelerated; on this basis, fast conveying bed riser reactors were used to carry out petroleum hydrocarbon catalytic cracking reactions, and the liquid product yield and selectivity of petroleum hydrocarbon catalytic cracking reactions were significantly improved.

[0005] Compared with the dense phase bed reactor, the riser reactor has obvious progress in structure and operation mode. The main performance is the mixing of oil gas and catalyst in the feed pipe section, the rapid separation of outlet products, the reduction of temperature gradient on the riser cross section, and the reduction of return. After the emergence of high-activity and high-selectivity zeolite catalysts that can significantly improve the reaction intensity, various types of fast conveying bed reactors, i.e. riser reactors, have been developed. Due to the excellent flexibility and flexibility of the riser reactor, it can realize the primary cracking of heavy oil, and the yield and selectivity of light oil are relatively ideal, so such reactors still have strong vitality to date. At present, a variable-diameter riser reactor (for example, the variable-diameter riser disclosed in CN99105903A, CN99109193A, CN99105904A, etc.) has been developed, which increases the diameter pipe section in the middle of the riser to form a fluidized bed reaction pipe section, thereby strengthening the secondary reaction of the generated gasoline. The variable-diameter riser reactor can perform primary cracking of heavy oil while taking into account the secondary conversion of gasoline; however, it is difficult for such a reactor to crack the recycled light hydrocarbon (such as gasoline) into smaller cracking gas molecules. When using such a reactor for light hydrocarbon (such as gasoline) cracking reaction, the liquid gas yield is less than 30%, and the propylene yield is less than 9%.

[0006] Light hydrocarbon 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 cracking gas, researchers in the field have proposed light hydrocarbon recycling technology, typically two kinds: (1) the gasoline or other light hydrocarbons are transported to the original heavy oil riser (usually injected into the upstream of the feed oil nozzle) for recycling; for example, USP5043522 and USP5846403 disclose that the catalytic cracking gasoline is injected into the upstream of the feed oil nozzle, and is catalytically converted by using high-temperature and high-activity regenerated catalyst; further, CN1160746A discloses that the straight-run gasoline, coking gasoline and other low-quality gasoline are injected into the lower part of the riser reactor to make them preferentially contact with the regenerated catalyst for reaction; (2) a separate gasoline or light hydrocarbon riser is used for recycling; for example, CN1069054A and USP3784463 disclose that a catalytic cracking unit with a double-riser reactor is used for reaction, and low-quality gasoline including catalytic cracking gasoline is injected into the gasoline riser reactor to realize catalytic upgrading of the low-quality gasoline by using high-temperature and large catalyst / oil ratio reaction conditions, so as to increase the yield of liquefied gas and the octane number of gasoline. The molecules generated after the light hydrocarbon feedstock contacts with the catalyst are relatively small, and the volume expansion is obvious, which has an impact on the heavy oil feedstock 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 large negative impact on the heavy oil reaction, the proportion of light hydrocarbon recycling in mode (1) is low. In mode (2), a separate light hydrocarbon recycling reactor is additionally provided on the basis of the traditional heavy oil reactor to recycle or secondarily crack the light hydrocarbon components, but the light hydrocarbon molecules are small, and the required catalyst density in the reactor is high, and the traditional riser cannot well meet the requirements of the contact reaction between the light hydrocarbon molecules and the catalyst.

[0007] In order to solve the above problems, researchers have developed some light hydrocarbon catalytic cracking devices suitable for light hydrocarbon catalytic cracking. For example, CN201520020322.2 discloses a light hydrocarbon catalytic cracking device, in which the light hydrocarbon and the catalyst transported from the catalyst riser contact and react in an expanded-diameter reactor. In the expanded-diameter reactor, the catalyst enters the catalyst distributor from the outlet of the riser, and the light hydrocarbon enters the light hydrocarbon distributor, and the catalyst and the light hydrocarbon realize contact strengthening and contact reaction through the catalyst distributor and the light hydrocarbon distributor. The current light hydrocarbon catalytic cracking devices generally have the problems of complex internal components, only one light hydrocarbon feedstock can realize strengthened contact reaction with the catalyst, limited processing capacity and light hydrocarbon processing efficiency, and unstable gas-solid fluidization in the expanded-diameter reactor.

[0008] In summary, there is still a need to solve the problems of complex internal components of the light hydrocarbon catalytic cracking device, only one light hydrocarbon feedstock can realize strengthened contact reaction with the catalyst, limited processing capacity and light hydrocarbon processing efficiency, and unstable gas-solid fluidization in the expanded-diameter reactor. SUMMARY

[0009] The present application aims to provide a light hydrocarbon catalytic cracking device and a corresponding light hydrocarbon catalytic cracking method, which are suitable for light hydrocarbon catalytic cracking, have simple structure, can realize enhanced contact reaction of multi-strand light hydrocarbon feed and catalyst, and stabilize the gas-solid fluidization in the diameter-expanded reactor.

[0010] To solve the above problems, the present application provides the following two technical solutions.

[0011] In a first aspect, the present application provides a light hydrocarbon catalytic cracking device, wherein the device comprises a liquid hydrocarbon treatment pipe, a coarse separation equipment, and a gaseous hydrocarbon diameter-expanded reactor.

[0012] The gaseous hydrocarbon diameter-expanded reactor is a tubular shell with open top and bottom and is provided with a gaseous hydrocarbon feed port at the bottom. The coarse separation equipment is a variable-diameter pipe comprising a bottom pipe section, a middle pipe section, and a top pipe section from bottom to top, and the pipe diameter of the top pipe section is < the pipe diameter of the bottom pipe section < the pipe diameter of the middle pipe section (the inner diameter of the top pipe section < the inner diameter of the bottom pipe section < the inner diameter of the middle pipe section, and the outer diameter of the top pipe section < the outer diameter of the bottom pipe section < the outer diameter of the middle pipe section). The coarse separation equipment is arranged in the gaseous hydrocarbon diameter-expanded reactor, with the bottom end located in the middle pipe section (1 / 3-2 / 3 length pipe section from bottom to top of the gaseous hydrocarbon diameter-expanded reactor) or the bottom pipe section (0-1 / 3 length pipe section from bottom to top of the gaseous hydrocarbon diameter-expanded reactor) of the gaseous hydrocarbon diameter-expanded reactor, and the top end located at the top end of the gaseous hydrocarbon diameter-expanded reactor or outside the gaseous hydrocarbon diameter-expanded reactor (to enable the stream discharged from the top end of the coarse separation equipment to enter the equipment connected to the top opening of the gaseous hydrocarbon diameter-expanded reactor, such as a reactant riser). The liquid hydrocarbon treatment pipe is provided with a cyclone nozzle at the tail end, and the tail end of the liquid hydrocarbon treatment pipe penetrates into the interior of the gaseous hydrocarbon diameter-expanded reactor from the bottom opening of the gaseous hydrocarbon diameter-expanded reactor, penetrates into the interior of the coarse separation equipment from the bottom end of the coarse separation equipment, and is located in the middle pipe section of the coarse separation equipment.

[0013] In the present application, the tail end of the pipe refers to the outlet end of the pipe, the head end of the pipe refers to the inlet end of the pipe, the tail part of the pipe refers to the outlet part pipe section of the pipe, and the head part of the pipe refers to the inlet part pipe section of the pipe.

[0014] In the above light hydrocarbon catalytic cracking device, liquid hydrocarbon and catalyst are contacted in the liquid hydrocarbon treatment pipe and catalytic cracking reaction is carried out, and the mixture after reaction is separated from the catalyst through the cyclone nozzle of the liquid hydrocarbon treatment pipe and the coarse separation device; wherein the mixture enters the middle pipe section of the coarse separation device through the cyclone nozzle of the liquid hydrocarbon treatment pipe and generates cyclone, the catalyst slides into the bottom pipe section of the coarse separation device with smaller inner diameter, and the oil gas enters the top pipe section of the coarse separation device with smaller inner diameter, so as to realize the coarse separation of the oil gas and the catalyst. The separated oil gas enters the device connected with the top opening of the gas hydrocarbon diameter expansion reactor through the top end of the coarse separation device for subsequent treatment, and the separated catalyst enters the gas hydrocarbon diameter expansion reactor through the bottom end of the coarse separation device; wherein the catalyst enters the gas hydrocarbon diameter expansion reactor from the bottom end of the coarse separation device, and due to the increase of the horizontal cross-sectional area of the gas hydrocarbon diameter expansion reactor, the linear velocity of the oil gas flow is significantly reduced, the catalyst falls into the lower part of the gas hydrocarbon diameter expansion reactor, and the catalyst density in the lower part of the gas hydrocarbon diameter expansion reactor is higher. In the space formed between the gas hydrocarbon diameter expansion reactor and the coarse separation device and the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor, the gas hydrocarbon contacts with the catalyst from the coarse separation device and reacts; wherein the gas hydrocarbon and the catalyst from the coarse separation device first carry out catalytic cracking reaction at a relatively slow flow rate in the larger space, i.e. the dense phase section, formed between the gas hydrocarbon diameter expansion reactor and the bottom pipe section of the coarse separation device and between the gas hydrocarbon diameter expansion reactor and the liquid hydrocarbon treatment pipe, and the mixture after the catalytic cracking reaction includes the catalyst and the oil gas, which passes through the relatively narrow space formed between the gas hydrocarbon diameter expansion reactor and the middle pipe section of the coarse separation device to accelerate the flow rate of the oil gas and the catalyst, so as to more stably take out the oil gas and the catalyst in the lower part of the gas hydrocarbon diameter expansion reactor. The mixture after reaction passes through the space formed between the gas hydrocarbon diameter expansion reactor and the top pipe section of the coarse separation device and enters the device connected with the top opening of the gas hydrocarbon diameter expansion reactor for subsequent treatment.

[0015] In the above light hydrocarbon catalytic cracking device, through the special connection and coupling mode of the liquid hydrocarbon treatment pipe, the coarse separation device and the gas hydrocarbon diameter expansion reactor, the catalyst after contacting with the liquid hydrocarbon, which is at high temperature and still has high activity, is deposited in the middle and lower part of the gas hydrocarbon diameter expansion reactor, then contacts with the gas hydrocarbon and reacts, and the contact between the light hydrocarbon and the catalyst is strengthened and the gas-solid fluidization is stabilized in the gas hydrocarbon diameter expansion reactor by means of the space formed between the gas hydrocarbon diameter expansion reactor and the coarse separation device, so as to achieve the purpose of realizing the strengthened contact reaction between the two light hydrocarbon feeds and the catalyst and stabilizing the gas-solid fluidization in the gas hydrocarbon diameter expansion reactor through simple structure.

[0016] In the above light hydrocarbon catalytic cracking device, the coarse separation device can realize the coarse separation of the oil gas and the catalyst, and also plays the role of fluidization and flow regulation for the fluid in the gas hydrocarbon diameter expansion reactor.

[0017] According to the preferred implementation of the first aspect, wherein the light hydrocarbon catalytic cracking device comprises a liquid hydrocarbon treatment pipe, a rough separation device, a gas hydrocarbon diameter expansion reactor and a reactant riser;

[0018] The gas hydrocarbon diameter expansion reactor is a tubular shell with open top and bottom, and is provided with a gas hydrocarbon feeding port at the bottom. The top opening of the gas hydrocarbon diameter expansion reactor is connected with the head end of the reactant riser (which can realize the flow of the gas hydrocarbon diameter expansion reactor into the reactant riser). The rough separation device is a variable-diameter pipe, which comprises a bottom pipe section, a middle pipe section and a top pipe section from bottom to top, and the pipe diameter of the top pipe section is < the pipe diameter of the bottom pipe section < the pipe diameter of the middle pipe section (the inner diameter of the top pipe section < the inner diameter of the bottom pipe section < the inner diameter of the middle pipe section, and the outer diameter of the top pipe section < the outer diameter of the bottom pipe section < the outer diameter of the middle pipe section). The rough separation device is arranged in the gas hydrocarbon diameter expansion reactor, and the bottom end of the rough separation device is located in the middle pipe section (1 / 3-2 / 3 length pipe section from bottom to top of the gas hydrocarbon diameter expansion reactor) or the bottom pipe section (0-1 / 3 length pipe section from bottom to top of the gas hydrocarbon diameter expansion reactor) of the gas hydrocarbon diameter expansion reactor, and the top end is located at the top end of the gas hydrocarbon diameter expansion reactor or the head of the reactant riser (which can realize the flow from the top end of the rough separation device into the reactant riser). The liquid hydrocarbon treatment pipe is provided with a cyclone nozzle at the tail end. The tail end of the liquid hydrocarbon treatment pipe penetrates into the interior of the gas hydrocarbon diameter expansion reactor from the bottom opening of the gas hydrocarbon diameter expansion reactor, and penetrates into the interior of the rough separation device from the bottom end of the rough separation device, and is located in the middle pipe section of the rough separation device.

[0019] In the above light hydrocarbon catalytic cracking device, the oil gas discharged from the top end of the rough separation device and the reacted mixture discharged from the top end of the gas hydrocarbon diameter expansion reactor enter the reactant riser. The cross-sectional area of the reactant riser is small, and the linear velocity of the oil gas and the catalyst increases after entering the reactant riser. The gas-solid fluidization in the reactant riser is a fast transport bed state.

[0020] According to the preferred implementation of the first aspect, wherein the liquid hydrocarbon treatment pipe, the pipe section located in the gas hydrocarbon diameter expansion reactor, the gas hydrocarbon diameter expansion reactor and the rough separation device are coaxial.

[0021] According to the preferred implementation of the first aspect, wherein the light hydrocarbon catalytic cracking device comprises a liquid hydrocarbon treatment pipe, a rough separation device, a gas hydrocarbon diameter expansion reactor, a reactant riser and a reactant post-treatment unit;

[0022] The gas hydrocarbon diameter expansion reactor is a tubular shell with open top and bottom ends, the top end of the gas hydrocarbon diameter expansion reactor is connected with the head end of the reactant riser (so that the gas hydrocarbon diameter expansion reactor can be connected with the reactant riser), and the bottom end of the gas hydrocarbon diameter expansion reactor is provided with a gas hydrocarbon feeding port; the coarse separation device is a variable-diameter pipe, which comprises a bottom pipe section, a middle pipe section and a top pipe section from bottom to top, and the pipe diameter of the top pipe section < the pipe diameter of the bottom pipe section < the pipe diameter of the middle pipe section (the inner diameter of the top pipe section < the inner diameter of the bottom pipe section < the inner diameter of the middle pipe section, and the outer diameter of the top pipe section < the outer diameter of the bottom pipe section < the outer diameter of the middle pipe section); the coarse separation device is arranged in the gas hydrocarbon diameter expansion reactor, the bottom end of the coarse separation device is located in the middle pipe section (1 / 3-2 / 3 length pipe section of the gas hydrocarbon diameter expansion reactor from bottom to top) or the bottom pipe section (0-1 / 3 length pipe section of the gas hydrocarbon diameter expansion reactor from bottom to top) of the gas hydrocarbon diameter expansion reactor, and the top end of the coarse separation device is located at the top end of the gas hydrocarbon diameter expansion reactor or the head of the reactant riser (so that the flow discharged from the top end of the coarse separation device can enter the reactant riser); the tail end of the liquid hydrocarbon treatment pipe is provided with a cyclone nozzle, the tail end of the liquid hydrocarbon treatment pipe penetrates into the interior of the gas hydrocarbon diameter expansion reactor from the bottom end opening of the gas hydrocarbon diameter expansion reactor, penetrates into the interior of the coarse separation device from the bottom end of the coarse separation device, and is located in the middle pipe section of the coarse separation device, the pipe section of the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor, the gas hydrocarbon diameter expansion reactor and the coarse separation device are coaxial, and the reactant post-processing unit is connected with the tail end of the reactant riser.

[0023] According to the preferred embodiment of the first aspect, the ratio of the inner diameter of the gas hydrocarbon diameter expansion reactor to the outer diameter of the middle pipe section and the outer diameter of the bottom pipe section of the coarse separation device is 1:0.4-0.8:0.15-0.3.

[0024] In the above light hydrocarbon catalytic cracking device, the coarse separation device can realize the coarse separation of oil gas and catalyst, and can also play a fluidizing and rectifying role on the fluid in the gas hydrocarbon diameter expansion reactor.

[0025] According to the preferred embodiment of the first aspect, the liquid hydrocarbon treatment pipe is provided with a catalyst pre-lifting section and a liquid hydrocarbon reaction section, the tail end of the catalyst pre-lifting section is connected with the head end of the liquid hydrocarbon reaction section, and the inner diameter of the catalyst pre-lifting section < the inner diameter of the liquid hydrocarbon reaction section; the head of the catalyst pre-lifting section is provided with a catalyst inlet and a pre-lifting medium inlet; the head of the liquid hydrocarbon reaction section is provided with a liquid hydrocarbon feeding port; and the pipe section of the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor is the liquid hydrocarbon reaction section.

[0026] More preferably, the light hydrocarbon catalytic cracking device is further provided with a catalyst feeding inclined pipe, the catalyst feeding inclined pipe is connected with the catalyst feeding port of the catalyst pre-lifting section.

[0027] More preferably, the tail end of the catalyst pre-lifting section is directly or through a platform-shaped buffer section connected with the head end of the liquid hydrocarbon reaction section.

[0028] More preferably, the liquid hydrocarbon feed inlet is provided with at least two feed nozzles; further preferably, the feed nozzles are equally spaced on the sidewall of the liquid hydrocarbon reaction section, each feed nozzle is centrally symmetric, and the spray direction of each feed nozzle is towards the central axis; the spray direction of each feed nozzle forms an angle with the cross section of the liquid hydrocarbon reaction section (which can be downward or upward); further preferably, the spray direction of the feed nozzles forms an angle of 5°-60° (preferably 15°-45°) with the cross section of the liquid hydrocarbon reaction section, the cross section of the liquid hydrocarbon reaction section refers to the plane perpendicular to the axis of the liquid hydrocarbon reaction section; further preferably, the spray direction of the feed nozzles forms a downward angle with the cross section of the liquid hydrocarbon reaction section.

[0029] More preferably, the length of the catalyst pre-lifting section is 3-8 m; further preferably, the length of the catalyst pre-lifting section is 4-6 m.

[0030] More preferably, the length of the liquid hydrocarbon reaction section is 3-20 m; further preferably, the length of the liquid hydrocarbon reaction section is 5-15 m.

[0031] More preferably, the ratio of the inner diameter of the catalyst pre-lifting section to the inner diameter of the liquid hydrocarbon reaction section is less than 1:1 and greater than or equal to 1:1.8; further preferably, the ratio of the inner diameter of the catalyst pre-lifting section to the inner diameter of the liquid hydrocarbon reaction section is 1:1.1-1.4.

[0032] More preferably, the liquid hydrocarbon treatment pipe is vertically arranged, the head end of the catalyst pre-lifting section is the bottom end of the catalyst pre-lifting section, the tail end of the catalyst pre-lifting section is the top end of the catalyst pre-lifting section, the head end of the liquid hydrocarbon reaction section is the bottom end of the liquid hydrocarbon reaction section, and the tail end of the liquid hydrocarbon reaction section is the top end of the liquid hydrocarbon reaction section.

[0033] According to the preferred embodiment of the first aspect, the cyclone nozzle is provided with 2-6 fluid outlets which are equally spaced and axially symmetric.

[0034] According to the preferred embodiment of the first aspect, the direction of the fluid outlet of each cyclone nozzle is towards the pipe wall of the middle pipe section of the coarse separation device, and the angle between the direction of the fluid outlet of each cyclone nozzle and the pipe wall of the middle pipe section of the coarse separation device is the same and not equal to 90 degrees.

[0035] According to the preferred embodiment of the first aspect, the top end of the bottom pipe section of the coarse separation device is directly or through a platform-shaped buffer section connected with the bottom end of the middle pipe section of the coarse separation device.

[0036] According to the preferred embodiment of the first aspect, wherein the top end of the middle tube section of the rough separation device is connected to the bottom end of the top tube section of the rough separation device directly or through a dome-shaped buffer section.

[0037] According to the preferred embodiment of the first aspect, wherein the ratio of the outer diameter of the tube section inside the gas hydrocarbon up-sizing reactor, the inner diameter of the middle tube section of the rough separation device, the inner diameter of the bottom tube section of the rough separation device is 1:2-3:1.2-1.4.

[0038] According to the preferred embodiment of the first aspect, wherein the ratio of the inner diameter of the top tube section of the rough separation device, the inner diameter of the bottom tube section of the rough separation device, the inner diameter of the middle tube section of the rough separation device is 1:1.2-1.4:2-3.

[0039] According to the preferred embodiment of the first aspect, wherein the length of the middle tube section of the rough separation device is 0.5-3m; more preferably, the length of the middle tube section of the rough separation device is 1-2m;

[0040] According to the preferred embodiment of the first aspect, wherein the length of the bottom tube section of the rough separation device is 0.5-7m; more preferably, the length of the bottom tube section of the rough separation device is 1-6m;

[0041] According to the preferred embodiment of the first aspect, wherein the length of the top tube section of the rough separation device is 0.5-2m; more preferably, the length of the top tube section of the rough separation device is 0.6-1.5m;

[0042] According to the preferred embodiment of the first aspect, wherein the gas hydrocarbon up-sizing reactor is provided with a gas hydrocarbon feed distributor at the gas hydrocarbon feed inlet;

[0043] More preferably, the gas hydrocarbon feed distributor is selected from one of the following: a ring-shaped feed pipe with multiple (at least two) nozzles, a concentric ring-shaped feed pipe with multiple (at least two) nozzles, and a dendritic distribution pipe with multiple (at least two) nozzles.

[0044] According to the preferred embodiment of the first aspect, wherein the bottom tube section of the gas hydrocarbon up-sizing reactor is provided with a gas distribution plate;

[0045] The gas light hydrocarbon enters the gas hydrocarbon up-sizing reactor through the holes of the gas distribution plate, which is more conducive to realizing the efficient contact between the light hydrocarbon and the catalyst;

[0046] More preferably, the gas distribution plate is arranged in a manner of high in the center and low at the periphery in the gas hydrocarbon up-sizing reactor, so as to facilitate the fluidization of the catalyst flowing out of the bottom of the rough separation device at the bottom of the gas hydrocarbon up-sizing reactor; further preferably, the height difference between the center and the periphery of the gas distribution plate is 0.1-1m; more preferably, the height difference between the center and the periphery of the gas distribution plate is 0.2-0.7m;

[0047] More preferably, the holes on the gas distribution plate are uniformly distributed;

[0048] More preferably, the walls of the holes on the gas distribution plate are provided with ceramic wear-resistant lining;

[0049] More preferably, the diameter of the holes on the gas distribution plate is 5-60 mm; further preferably, the diameter of the holes on the gas distribution plate is 10-30 mm;

[0050] More preferably, the total open area ratio of the gas distribution plate is 5%-50%; further preferably, the total open area ratio of the gas distribution plate is 15%-30%;

[0051] More preferably, the height of the center of the gas distribution plate from the bottom end of the gas hydrocarbon up-sizing reactor is 0.2-2 m; further preferably, the height of the center of the gas distribution plate from the bottom end of the gas hydrocarbon up-sizing reactor is 0.3-1 m;

[0052] More preferably, the height of the center of the gas distribution plate from the fluid outlet of the cyclone nozzle is 1-8 m; further preferably, the height of the center of the gas distribution plate from the fluid outlet of the cyclone nozzle is 2-5 m;

[0053] More preferably, the height of the center of the gas distribution plate from the bottom end of the middle pipe section of the coarse separation device is 0.3-1 m.

[0054] According to the preferred embodiments of the first aspect, the ratio of the inner diameter of the reactant riser to the inner diameter of the gas hydrocarbon up-sizing reactor is 1:2-5, preferably 1:3-4.

[0055] According to the preferred embodiments of the first aspect, the length of the reactant riser is 3-30 meters; more preferably, the length of the reactant riser is 5-15 meters.

[0056] According to the preferred embodiments of the first aspect, the reactant riser is vertically arranged, the head end of the reactant riser is the bottom end of the reactant riser, and the tail end of the reactant riser is the top end of the reactant riser.

[0057] According to the preferred embodiments of the first aspect, the reactant post-processing unit comprises a settler, the upper part of the settler is provided with a gas-solid separation system, the feed inlet of the gas-solid separation system is connected with the tail end of the reactant riser, the gas-solid separation system is used to separate the catalyst from the oil gas, the lower part of the settler is provided with a stripping system to strip the catalyst separated from the gas-solid separation system, the top of the settler is provided with a gas outlet, and the bottom is provided with a catalyst outlet;

[0058] In the settler, the catalysts with deposited coke are separated from the oil gas by using a gas-solid separation system, the separated oil gas is discharged from the gas outlet of the settler to a subsequent oil gas fractionating tower, etc., the catalysts with coke fall into the stripping system at the lower part of the settler from the solid outlet of the separation system, in the stripping system, the volatile hydrocarbon gas entrained on the catalysts with coke is separated by using water vapor and is mixed into the oil gas separated from the gas-solid separation system to be discharged from the gas outlet of the settler to the subsequent oil gas fractionating tower, the catalysts after separation of the volatile hydrocarbon gas are discharged from the catalyst outlet of the settler;

[0059] More preferably, a gas collecting device is arranged at the gas outlet at the top of the settler;

[0060] More preferably, the gas-solid separation system adopts an inertial separation device or a cyclone separation device (for example, a 1-3 stage gas cyclone separation device); further preferably, the inertial separation device includes one of an umbrella cap type inertial separation, an inverted L type inertial separation, a T type inertial separation, a three-leaf type inertial separation and a catapult type inertial separation; further preferably, the cyclone separation device is a volute type cyclone separation device or a straight-cut type cyclone separation device;

[0061] More preferably, the reactant post-treatment unit further includes a regenerator, the catalyst outlet of the settler is connected with the feed inlet of the regenerator, and the catalyst outlet of the regenerator is communicated with the catalyst feed inlet of the catalyst pre-lifting section, so as to realize that the catalyst after stripping treatment in the stripping system enters the regenerator for regeneration treatment, and the catalyst after regeneration treatment of the regenerator enters the catalyst pre-lifting section for utilization.

[0062] In the second aspect, the present application provides a light hydrocarbon catalytic cracking method, which is carried out by using the light hydrocarbon catalytic cracking device provided in the first aspect of the present application, and specifically includes the following steps:

[0063] 1) In the liquid hydrocarbon treatment pipe, the liquid light hydrocarbon raw material is contacted with the catalyst to occur catalytic cracking reaction;

[0064] 2) The mixture (including oil gas and catalyst) obtained after the catalytic cracking reaction in the liquid hydrocarbon treatment pipe is discharged from the cyclone nozzle of the liquid hydrocarbon treatment pipe into the middle pipe section of the coarse separation device and occurs cyclone, the catalyst in the mixture slides into the bottom pipe section of the coarse separation device and then enters the gas hydrocarbon diameter expansion reactor through the tail end of the coarse separation device, the oil gas in the mixture enters into the top pipe section of the coarse separation device and then enters the reactant lifting pipe through the top end of the coarse separation device;

[0065] 3) the catalytic cracking reaction of the gaseous light hydrocarbon feedstock with the catalyst in the gas hydrocarbon upgrader dense section occurs, and the mixture (including catalyst and oil gas) after the catalytic cracking reaction enters the reactor riser after passing through the space between the gas hydrocarbon upgrader and the middle and top pipe sections of the crude separation equipment; wherein the gas hydrocarbon upgrader dense section refers to the space formed between the gas hydrocarbon upgrader and the bottom pipe section of the crude separation equipment and between the gas hydrocarbon upgrader and the liquid hydrocarbon processing pipe below the middle pipe section of the crude separation equipment in the gas hydrocarbon upgrader;

[0066] 4) the oil gas from step 2) and the mixture from step 3) that enter the reactor riser fluid pass through the tail end of the reactor riser to enter the reactor post-treatment unit for post-treatment.

[0067] According to the preferred embodiments of the second aspect, wherein in step 1), the catalytic cracking reaction of the liquid light hydrocarbon feedstock with the catalyst in the liquid hydrocarbon processing pipe includes:

[0068] In the liquid hydrocarbon processing pipe, the pre-lift medium entering the liquid hydrocarbon processing pipe contacts the catalyst entering the liquid hydrocarbon processing pipe and fluidizes the catalyst to flow along the liquid hydrocarbon processing pipe;

[0069] The liquid light hydrocarbon feedstock is atomized and enters the liquid hydrocarbon processing pipe, contacts the catalyst flowing in the liquid hydrocarbon processing pipe and undergoes a catalytic cracking reaction;

[0070] Further, the pre-lift medium is selected from water vapor or dry gas;

[0071] Further, the temperature of the catalyst entering the liquid hydrocarbon processing pipe before contacting the pre-lift medium is 660-760°C;

[0072] Further, the temperature of the mixture at the position of the cyclone nozzle is 560-650°C; further, the temperature of the mixture at the position of the cyclone nozzle is 580-630°C;

[0073] Further, the apparent residence time of the oil gas in the liquid hydrocarbon processing pipe is 0.8-2 seconds.

[0074] According to the preferred embodiments of the second aspect, wherein the reaction temperature of the catalytic cracking reaction of the gaseous light hydrocarbon feedstock with the catalyst in the gas hydrocarbon upgrader dense section is 540-630°C;

[0075] More preferably, the reaction temperature of the catalytic cracking reaction of the gaseous light hydrocarbon feedstock with the catalyst in the gas hydrocarbon upgrader dense section is 560-620°C.

[0076] According to a preferred embodiment of the second aspect, the apparent residence time of the oil gas in the gaseous hydrocarbon up-scaling reactor is 1.5-10 seconds.

[0077] More preferably, the apparent residence time of the oil gas in the gaseous hydrocarbon up-scaling reactor is 2-5 seconds.

[0078] According to a preferred embodiment of the second aspect, the apparent linear velocity of the oil gas in the dense phase section of the gaseous hydrocarbon up-scaling reactor is 0.7-1.4 m / s, and the oil gas is maintained in a turbulent flow state in the dense phase section of the gaseous hydrocarbon up-scaling reactor.

[0079] According to a preferred embodiment of the second aspect, the method further comprises:

[0080] (5) in the reactant post-treatment unit, the fluid from the reactant riser is subjected to gas-solid separation to separate the catalyst from the oil gas, the separated catalyst is subjected to stripping treatment, the oil gas after stripping treatment is discharged from the reactant post-treatment unit together with the oil gas obtained by gas-solid separation and is collected, and the catalyst after stripping treatment is collected;

[0081] More preferably, the catalyst after stripping treatment is collected is subjected to air calcination regeneration, and the regenerated catalyst is reused in the liquid hydrocarbon treatment pipe.

[0082] According to a preferred embodiment of the second aspect, during the catalytic cracking reaction process of the gaseous light hydrocarbon raw material and the catalyst in step 3), water vapor not more than 8% of the mass of the gaseous light hydrocarbon raw material is injected into the bottom of the up-scaling reactor to adjust the fluidization state of the catalyst and the partial pressure of the hydrocarbon, thereby strengthening the cracking reaction path of the gaseous light hydrocarbon raw material.

[0083] According to a preferred embodiment of the second aspect, the method further comprises: injecting a quenching agent into the oil gas from step 2) and the mixture fluid from step 3) entering the reactant riser; and using the quenching agent to control the temperature of the fluid in the reactant riser to control the reaction of the fluid in the reactant riser.

[0084] More preferably, the quenching agent comprises one or a combination of two or more of water, backer oil, gasoline, diesel oil, and slop oil.

[0085] More preferably, the injection amount of the quenching agent is 1-10 wt% of the catalytic addition amount.

[0086] More preferably, the temperature of the quenching agent is normal temperature-200°C; and further preferably, the temperature of the quenching agent is normal temperature.

[0087] According to the preferred embodiment of the second aspect, the liquid light hydrocarbon feedstock comprises one or more than two kinds of mixture of olefin-rich gasoline, diesel, and light hydrocarbon with carbon number of 4-8; wherein the olefin-rich gasoline refers to gasoline with olefin content of 40v% or more;

[0088] More preferably, the olefin-rich gasoline comprises one or more than two kinds of mixture of catalytic cracking gasoline, catalytic cracking gasoline, coking gasoline, thermal cracking gasoline, and thermal cracking gasoline.

[0089] More preferably, the light hydrocarbon with carbon number of 4-8 comprises one or more than two kinds of mixture of straight-run naphtha, straight-run gasoline, hydrogenated naphtha, alkane with carbon number of 4-8, and raffinate oil.

[0090] According to the preferred embodiment of the second aspect, the gas light hydrocarbon feedstock is selected from low-carbon light hydrocarbon with olefin-rich, wherein the low-carbon light hydrocarbon with olefin-rich refers to low-carbon light hydrocarbon with olefin content of 40v% or more, and the low-carbon has carbon number of 3-8; more preferably, the low-carbon has carbon number of 3-6.

[0091] More preferably, the low-carbon light hydrocarbon with olefin-rich comprises one or more than two kinds of mixture of catalytic cracking gasoline, catalytic cracking gasoline, coking gasoline, thermal cracking gasoline, and thermal cracking gasoline.

[0092] More preferably, the light hydrocarbon with carbon number of 4-8 comprises one or more than two kinds of mixture of ether post-C4 light hydrocarbon, ether post-light gasoline, catalytic light gasoline, coking light gasoline, and thermal cracking light gasoline.

[0093] According to the preferred embodiment of the second aspect, the catalyst is selected from light hydrocarbon catalytic cracking or catalytic cracking catalyst, and the catalyst can be but is not limited to at least one selected from catalysts with active components selected from one or more than two kinds of combination of Y zeolite with or without rare earth, HY zeolite with or without rare earth, ultra-stable Y zeolite with or without rare earth, ZSM-5 zeolite with or without rare earth, and other high-silicon zeolites with five-membered ring structure, and amorphous silicon-aluminum catalyst.

[0094] The technical solution provided by the present application is suitable for light hydrocarbon catalytic cracking, can realize the enhanced contact reaction of multiple light hydrocarbon feedstocks and catalysts based on a simple structure device, and can realize the stability of gas-solid fluidization in the expanded diameter reactor. Compared with the prior art, the beneficial effects of the technical solution provided by the present application mainly reflect in the following aspects:

[0095] (1) The light hydrocarbon catalytic cracking device provided by the present application can realize the feeding of two light hydrocarbons and the effective contact with the catalyst.

[0096] The liquid hydrocarbon treatment pipe is used for processing liquid light hydrocarbon, and the liquid light hydrocarbon can be directly introduced and catalytically cracked, so that the liquid light hydrocarbon is provided with a separate contact environment with the high-temperature catalyst, and the cracking reaction of the light hydrocarbon is facilitated;

[0097] The liquid hydrocarbon treatment pipe, the coarse separation device and the gas hydrocarbon diameter expansion reactor are coupled through special design, the catalyst which is still high in temperature and high in activity after being contacted with the liquid light hydrocarbon is deposited in the middle and lower parts of the diameter expansion reactor, then the catalyst is contacted with and reacts with the gas light hydrocarbon, and the contact of the gas light hydrocarbon in the middle and lower parts of the gas hydrocarbon diameter expansion reactor with the catalyst is strengthened by using the space with different cross-sectional areas formed by the coarse separation device to control the gas linear velocity.

[0098] In summary, the light hydrocarbon catalytic cracking device provided by the present application realizes the controllable flow of the catalyst and oil gas and builds the reaction environment in which the two light hydrocarbon feeds are in contact with the catalyst, so that the light hydrocarbon processing capacity and the light hydrocarbon processing efficiency of the device are improved.

[0099] (2) The light hydrocarbon catalytic cracking device provided by the present application realizes the following through the coupling of the liquid hydrocarbon treatment pipe, the coarse separation device and the gas hydrocarbon diameter expansion reactor: A, the effective separation of the oil gas at the outlet of the liquid hydrocarbon treatment pipe from the catalyst, the oil gas after the catalytic cracking reaction of the liquid light hydrocarbon in the liquid hydrocarbon treatment pipe is discharged from the top of the coarse separation device, and the catalyst is discharged from the bottom of the coarse separation device and enters the lower part of the gas hydrocarbon diameter expansion reactor; B, the variable-diameter coarse separation device is arranged at a specific position in the diameter expansion reactor, so that the controllable flow and stable gas-solid fluidization of the oil gas and the catalyst in the diameter expansion reactor can be effectively realized, and the catalyst in the diameter expansion reactor can be brought out into the reaction material riser by the oil gas, so that the stability of the gas-solid fluidization in the diameter expansion reactor is effectively improved.

[0100] (3) The light hydrocarbon catalytic cracking device provided by the present application has multiple use modes and can flexibly adjust the product structure. The light hydrocarbon catalytic cracking device provided by the present application can be used alone, or can form a double-reactor system with a heavy oil catalytic cracking / catalytic cracking reactor (both can share a catalyst regeneration device or use separate catalyst regeneration devices, and the oil gas after the reaction can be introduced into the same oil gas separation device or separate oil gas separation devices).

[0101] The light hydrocarbon catalytic cracking device provided by the present application can be used for recycling the light hydrocarbon, gasoline and diesel oil etc. rich in C4-C8 olefins in a refinery or a petrochemical plant, so that the oil product quality, the diesel-gasoline ratio and the cracking gas yield can be improved, the production of raw materials required by the light hydrocarbon processing devices such as MTBE, light gasoline etherification and polypropylene can be increased, and the product structure of the refinery and petrochemical plant can be adjusted. BRIEF DESCRIPTION OF DRAWINGS

[0102] Figure 1 is a schematic diagram of the structure of the light hydrocarbon catalytic cracking device in Example 1.

[0103] Figure 2 is a schematic diagram of the structure of the cross section of the cyclone nozzle and the coarse separation equipment in Example 1.

[0104] Figure 3 is a schematic diagram of the structure of the light hydrocarbon catalytic cracking device in Comparative Example 1. DETAILED DESCRIPTION

[0105] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail below, but should not be understood as limiting the scope of the present application.

[0106] Example 1

[0107] The present embodiment provides a light hydrocarbon catalytic cracking device. As shown in Figure 1, the device comprises a liquid hydrocarbon treatment pipe 1, a coarse separation equipment 2, a gas hydrocarbon diameter expansion reactor 3, a reactant riser 4, a reactant post-treatment unit 5 and a catalyst feeding inclined pipe 6.

[0108] The liquid hydrocarbon treatment pipe 1 is provided with a catalyst pre-lifting section 11 and a liquid hydrocarbon reaction section 12 from the bottom end to the top end, the top end of the catalyst pre-lifting section 11 is connected with the bottom end of the liquid hydrocarbon reaction section 12 through a circular truncated cone-shaped buffer section, the inner diameter of the catalyst pre-lifting section 11 < the inner diameter of the liquid hydrocarbon reaction section 12; the bottom end of the catalyst pre-lifting section 11 is provided with a pre-lifting medium inlet 111, the bottom pipe section of the catalyst pre-lifting section 11 is provided with a catalyst inlet 112 near the bottom end position, the catalyst inlet 112 is connected with the catalyst feeding inclined pipe 6; the bottom end of the liquid hydrocarbon reaction section 12 is provided with a liquid hydrocarbon feeding port (not marked in FIG. 1); the liquid hydrocarbon feeding port is provided with two feeding nozzles (not marked in FIG. 1), each feeding nozzle is distributed on the side wall of the liquid hydrocarbon reaction section 12 at the same height (the height from the bottom end of the liquid hydrocarbon reaction section 12 is 0.5 m) and at the same interval, each feeding nozzle is centrally symmetric, the spraying direction of each feeding nozzle is towards the central axis, and the spraying direction of each feeding nozzle and the cross section of the liquid hydrocarbon reaction section 12 (the plane perpendicular to the axis of the liquid hydrocarbon reaction section) form an included angle of 30° (the downward included angle). The top end of the liquid hydrocarbon reaction section 12 is provided with a cyclone nozzle 121, the cyclone nozzle 121 is provided with three fluid outlets which are distributed at the same height and at the same interval, the direction of the fluid outlet of the cyclone nozzle 121 is towards the pipe wall of the middle pipe section of the coarse separation device 2, and the direction of each fluid outlet of the cyclone nozzle and the pipe wall of the middle pipe section of the coarse separation device form the same included angle which is not equal to 90 degrees. The length of the catalyst pre-lifting section 11 is 5 m, the length of the liquid hydrocarbon reaction section 12 is 15 m, the inner diameter of the catalyst pre-lifting section 11 is 0.5 m, the inner diameter of the liquid hydrocarbon reaction section 12 is 0.6 m, the outer diameter of the catalyst pre-lifting section 11 is 0.6 m, and the outer diameter of the liquid hydrocarbon reaction section 12 is 0.7 m.

[0109] The coarse separation device 2 is a variable-diameter pipe which includes a bottom pipe section, a middle pipe section and a top pipe section from the bottom end to the top end, and the pipe diameter of the top pipe section < the pipe diameter of the bottom pipe section < the pipe diameter of the middle pipe section (the inner diameter of the top pipe section < the inner diameter of the bottom pipe section < the inner diameter of the middle pipe section and the outer diameter of the top pipe section < the outer diameter of the bottom pipe section < the outer diameter of the middle pipe section), the top end of the bottom pipe section of the coarse separation device 2 is connected with the bottom end of the middle pipe section of the coarse separation device 2 through a circular truncated cone-shaped buffer section, and the top end of the middle pipe section of the coarse separation device 2 is connected with the bottom end of the top pipe section of the coarse separation device 2 through a dome-shaped buffer section. The inner diameter of the bottom pipe section of the coarse separation device 2 is 0.9 m, the inner diameter of the middle pipe section is 1.4 m, the inner diameter of the top pipe section is 0.45 m, the outer diameter of the bottom pipe section is 1.0 m, the outer diameter of the middle pipe section is 1.5 m, the outer diameter of the top pipe section is 0.55 m, the length of the bottom pipe section is 1 m, the length of the middle pipe section is 0.8 m, and the length of the top pipe section is 0.5 m.

[0110] The gas hydrocarbon up-sizing reactor 3 is a tubular shell with open top and bottom, which comprises a cylindrical body and a circular truncated cone top (diameter gradually decreases from top to bottom) ; the bottom end of the gas hydrocarbon up-sizing reactor 3 is provided with a gas hydrocarbon feeding port 12, and the gas hydrocarbon feeding port of the gas hydrocarbon up-sizing reactor 3 is provided with a gas hydrocarbon feeding distributor 31, which is selected as a ring-shaped feeding pipe with 10 nozzles. The position above the gas hydrocarbon feeding distributor 31 of the bottom pipe section of the gas hydrocarbon up-sizing reactor 3 is provided with a gas distribution plate 32; the gas distribution plate 32 is arranged in the gas hydrocarbon up-sizing reactor 3 in a manner that the center is high and the periphery is low, so as to facilitate the fluidization of the catalyst flowing out of the bottom of the coarse separation device in the bottom of the gas hydrocarbon up-sizing reactor; the height difference between the center and the periphery of the gas distribution plate 32 is 0.25 m; the holes on the gas distribution plate 32 are uniformly distributed, the walls of the holes on the gas distribution plate 32 are provided with ceramic wear-resistant lining, the diameter of the holes on the gas distribution plate 32 is 5 mm, and the total opening rate of the gas distribution plate 32 is 6%. The inner diameter (referring to the inner diameter of the cylindrical body) of the gas hydrocarbon up-sizing reactor 3 is 1.9 m, and the length of the gas hydrocarbon up-sizing reactor 3 is 3 m, wherein the length of the cylindrical body of the gas hydrocarbon up-sizing reactor 3 is 2.3 m.

[0111] The top end of the gas hydrocarbon up-sizing reactor 3 is connected with the bottom end of the reactant riser 4 (which can realize the flow of the gas hydrocarbon up-sizing reactor into the reactant riser). The coarse separation device 2 is arranged in the gas hydrocarbon up-sizing reactor 3, and the bottom end of the coarse separation device 2 is located in the lower pipe section of the gas hydrocarbon up-sizing reactor 3, and the top end is located in the bottom of the reactant riser (which can realize the flow of the material discharged from the top end of the coarse separation device 2 into the reactant riser 4) ; the top end of the liquid hydrocarbon reaction section 12 of the liquid hydrocarbon treatment pipe 1 penetrates into the inside of the gas hydrocarbon up-sizing reactor 3 from the bottom opening of the gas hydrocarbon up-sizing reactor 3, and penetrates into the inside of the coarse separation device 2 from the bottom end of the coarse separation device 2, and is located in the middle pipe section of the coarse separation device 2, and the liquid hydrocarbon treatment pipe 1, the gas hydrocarbon up-sizing reactor 3 and the coarse separation device 2 are coaxial, wherein the cross section of the cyclone nozzle 121 and the coarse separation device 2 is shown in Fig. 2. The height of the center of the gas distribution plate 32 from the bottom end of the gas hydrocarbon up-sizing reactor is 0.3 m, and the height of the center of the gas distribution plate 32 from the fluid outlet of the cyclone nozzle 121 is 1.7 m.

[0112] The inner diameter of the reactant riser 4 is 0.6 m, and the length of the reactant riser 4 is 18 m.

[0113] The reactant post-treatment unit 5 comprises a settler 51 and a regenerator (not labeled in Fig. 1). The upper part of the settler 51 is provided with a gas-solid separation system 511 for separating the catalyst from the oil gas. The lower part of the settler 51 is provided with a stripping system 512 for stripping the catalyst separated from the gas-solid separation system 511. The top of the settler 51 is provided with a gas outlet 513, and the bottom of the settler 51 is provided with a catalyst outlet 514. The top of the settler 51 is provided with a gas collecting device 515 for collecting the oil gas separated from the gas-solid separation system 511 and the oil gas stripped by the stripping system 512. The top end of the reactant riser 4 extends into the settler 51 from the bottom end of the settler 51 and is connected to the feed inlet of the gas-solid separation system 511. The gas outlet 513 of the settler 51 is connected to the oil gas outlet pipeline 7. The catalyst outlet 514 of the settler 51 is connected to the feed inlet of the regenerator, and the catalyst outlet of the regenerator is connected to the catalyst feed inclined pipe 6, so that the catalyst after the stripping treatment in the stripping system 512 enters the regenerator for regeneration treatment, and the catalyst after the regeneration treatment in the regenerator enters the catalyst pre-lifting section 11 through the catalyst feed inclined pipe 6 for reuse.

[0114] The embodiment also provides a light hydrocarbon catalytic cracking method, which is performed by using the light hydrocarbon catalytic cracking device provided by the embodiment and specifically includes the following steps.

[0115] 1) The pre-lifting medium (steam) enters the catalyst pre-lifting section 11 of the liquid hydrocarbon treatment pipe 1 from the bottom end of the catalyst pre-lifting section 11. In the catalyst pre-lifting section 11 of the liquid hydrocarbon treatment pipe 1, the pre-lifting medium contacts the high-temperature catalyst (the composition and properties of which are shown in Table 2) entering the catalyst pre-lifting section 11 of the liquid hydrocarbon treatment pipe 1, fluidizes the catalyst, and makes the catalyst flow along the liquid hydrocarbon treatment pipe 1.

[0116] The liquid light hydrocarbon raw material (the composition of which is shown in Table 1) enters the liquid hydrocarbon reaction section 12 of the liquid hydrocarbon treatment pipe 1 from the liquid hydrocarbon feed inlet at the bottom end of the liquid hydrocarbon reaction section 12 and is atomized. In the liquid hydrocarbon reaction section 12 of the liquid hydrocarbon treatment pipe 1, the atomized liquid light hydrocarbon raw material contacts the catalyst flowing in the liquid hydrocarbon treatment pipe 1 and performs a catalytic cracking reaction.

[0117] 2) The mixture (including oil gas and catalyst) obtained after the catalytic cracking reaction in the liquid hydrocarbon reaction section 12 of the liquid hydrocarbon treatment pipe 1 is discharged from the cyclone nozzle 121 into the middle pipe section of the coarse separation device 2 and is subjected to cyclone. The catalyst in the mixture slides into the bottom pipe section of the coarse separation device 2 and then enters the gas hydrocarbon diameter expansion reactor 3 through the tail end of the coarse separation device 2. The oil gas in the mixture enters the top pipe section of the coarse separation device 2 and then enters the reactant riser 4 through the top end of the coarse separation device 2.

[0118] 3) The gaseous light hydrocarbon feedstock (its composition is shown in Table 3) enters the gaseous hydrocarbon upgrader 3 through the gaseous hydrocarbon feed inlet at the bottom end of the gaseous hydrocarbon upgrader 3 and enters the gaseous hydrocarbon upgrader 3 through the gas distributor 32 into the dense catalyst section of the gaseous hydrocarbon upgrader 3; in the dense catalyst section of the gaseous hydrocarbon upgrader 3, the gaseous light hydrocarbon feedstock is catalytically cracked with the catalyst entering the gaseous hydrocarbon upgrader 3 through the tail end of the coarse separation device 2; wherein the dense catalyst section of the gaseous hydrocarbon upgrader 3 refers to the space between the gaseous hydrocarbon upgrader 3 and the bottom pipe section of the coarse separation device 2 and between the gaseous hydrocarbon upgrader 3 and the liquid hydrocarbon processing pipe 2 above the gas distributor 32 and below the middle pipe section of the coarse separation device 2 in the gaseous hydrocarbon upgrader 3. The mixture (including catalyst and oil gas) after the catalytic cracking reaction enters the reaction material riser 4 through the space between the gaseous hydrocarbon upgrader 3 and the middle pipe section of the coarse separation device 2 and between the gaseous hydrocarbon upgrader 3 and the top pipe section of the coarse separation device 2 in the gaseous hydrocarbon upgrader 3.

[0119] Wherein, during the catalytic cracking reaction of the gaseous light hydrocarbon feedstock with the catalyst, 2% of the mass of the gaseous light hydrocarbon feedstock entering the gaseous hydrocarbon upgrader 2 through the bottom end of the gaseous hydrocarbon upgrader 2 is injected into the gaseous hydrocarbon upgrader 2 as water vapor for adjusting the fluidization state of the catalyst and the partial pressure of the hydrocarbon, thereby strengthening the cracking reaction path of the gaseous light hydrocarbon feedstock.

[0120] 4) The oil gas from step 2) and the mixture from step 3) entering the reaction material riser 4 enter the reaction material post-processing unit 5 through the top end of the reaction material riser 4 for post-processing.

[0121] During the process, a quenching agent is injected into the oil gas from step 2) and the mixture from step 3) entering the reaction material riser 4 to control the temperature of the fluid in the reaction material riser 4; wherein the quenching agent is selected as olefin-rich gasoline with an olefin content of 42v%.

[0122] 5) In the reaction material post-processing unit 5, the fluid from the reaction material riser 4 is subjected to gas-solid separation in the settler 51 to separate the catalyst from the oil gas, the separated catalyst is subjected to stripping treatment, the oil gas after the stripping treatment is discharged together with the oil gas obtained from the gas-solid separation from the settler 51 and enters the oil gas outlet pipeline 7, and the catalyst after the stripping treatment is collected. The collected catalyst after the stripping treatment enters the regenerator for air coke-burning regeneration, and the regenerated catalyst reenters the liquid hydrocarbon processing pipe 1 for recycling.

[0123] The operating parameters of each step in this embodiment and the properties of the products collected by the oil gas outlet pipeline 7 are shown in Table 4.

[0124] Example 2

[0125] The present embodiment provides a light hydrocarbon catalytic cracking method, which uses the light hydrocarbon catalytic cracking device as in Embodiment 1, uses the same types of raw materials as in Embodiment 1, and has a similar step process as in Embodiment 1, with the only difference being that the operating parameters are not exactly the same as in Embodiment 1. See Table 4 for the specific operating parameters and the properties of the products collected by the oil and gas outlet pipeline 7.

[0126] Embodiment 3

[0127] The present embodiment provides a light hydrocarbon catalytic cracking device, which has a similar structure to the light hydrocarbon catalytic cracking device provided in Embodiment 1, with the only difference being that:

[0128] The spray direction of the feed nozzle forms a 45° angle (upward angle) with the cross-section of the liquid hydrocarbon reaction section 12 (the plane perpendicular to the axis of the liquid hydrocarbon reaction section). The cyclone nozzle 121 is provided with 2 fluid outlets with equal spacing.

[0129] The length of the catalyst pre-lifting section 11 is 3 m, the length of the liquid hydrocarbon reaction section 12 is 16 m, the inner diameter of the catalyst pre-lifting section 11 is 0.3 m, the inner diameter of the liquid hydrocarbon reaction section 12 is 0.48 m, the outer diameter of the catalyst pre-lifting section 11 is 0.4 m, and the outer diameter of the liquid hydrocarbon reaction section 12 is 0.58 m.

[0130] The inner diameter of the bottom section of the crude separation device 2 is 0.6 m, the inner diameter of the middle section is 1.5 m, the inner diameter of the top section is 0.4 m, the outer diameter of the bottom section is 0.7 m, the outer diameter of the middle section is 1.6 m, the outer diameter of the top section is 0.5 m, the length of the bottom section is 1.6 m, the length of the middle section is 0.6 m, and the length of the top section is 0.25 m.

[0131] The height difference between the center and the periphery of the gas distribution plate 32 is 0.18 m; the diameter of the holes on the gas distribution plate 32 is 30 mm, and the total opening rate on the gas distribution plate 32 is 25%. The inner diameter of the gas hydrocarbon expansion reactor 3 (referring to the inner diameter of the cylindrical body) is 2.1 m, and the length of the gas hydrocarbon expansion reactor 3 is 3.5 m, of which the length of the cylindrical body of the gas hydrocarbon expansion reactor 3 is 3 m.

[0132] The height of the gas distribution plate 32 from the bottom end of the gas hydrocarbon expansion reactor is 0.35 m, and the height of the gas distribution plate 32 from the fluid outlet of the cyclone nozzle 121 is 2.8 m.

[0133] The inner diameter of the reactant riser 4 is 0.6 m, and the length of the reactant riser 4 is 16 m.

[0134] The embodiment provides a light hydrocarbon catalytic cracking method, which uses the light hydrocarbon catalytic cracking device provided in the embodiment, uses the same raw materials as in the embodiment 1, and has a similar step process to the embodiment 1, and the only difference is that the operation parameters are not completely the same as those in the embodiment 1. For specific operation parameters and the properties of products collected by the oil and gas outlet pipeline 7, refer to Table 4.

[0135] Comparative example 1

[0136] The comparative example provides a light hydrocarbon cracking riser catalytic device. As shown in FIG. 3, the device comprises a light hydrocarbon treatment pipe 81, a reactant post-treatment unit 82 and a catalyst feeding inclined pipe 83.

[0137] The light hydrocarbon treatment pipe 81 is provided with a catalyst pre-lifting section 811 and a light hydrocarbon reaction section 812 from the bottom end to the top end. The top end of the catalyst pre-lifting section 811 is connected to the bottom end of the light hydrocarbon reaction section 812 through a circular truncated cone buffer section, and the inner diameter of the catalyst pre-lifting section 811 is < the inner diameter of the light hydrocarbon reaction section 812. The bottom end of the catalyst pre-lifting section 811 is provided with a pre-lifting medium inlet 8111, and the bottom pipe section of the catalyst pre-lifting section 811 is provided with a catalyst inlet 8112 near the bottom end position, and the catalyst inlet 8112 is connected with the catalyst feeding inclined pipe 83. The bottom end of the light hydrocarbon reaction section 812 is provided with a gaseous hydrocarbon feeding port (not labeled in FIG. 3) and a liquid hydrocarbon feeding port (not labeled in FIG. 3); the liquid hydrocarbon feeding port is provided with two feeding nozzles (not labeled in FIG. 3), each feeding nozzle is distributed at the same height (6m from the bottom end of the light hydrocarbon reaction section 812) and at the same interval on the side wall of the light hydrocarbon reaction section 812, each feeding nozzle is centrally symmetric, the spraying direction of each feeding nozzle is towards the central axis, and the spraying direction of each feeding nozzle forms an angle of 30° (downward angle) with the cross section (a plane perpendicular to the axis of the liquid hydrocarbon reaction section) of the light hydrocarbon reaction section 812; the light hydrocarbon feeding port of the light hydrocarbon reaction section 812 is provided with a light hydrocarbon feeding distributor, and the gaseous hydrocarbon feeding distributor is selected as a ring-shaped feeding pipe with 8 nozzles. The length of the catalyst pre-lifting section 811 is 5m, the length of the light hydrocarbon reaction section 812 is 36m, the inner diameter of the catalyst pre-lifting section 811 is 0.5m, the inner diameter of the light hydrocarbon reaction section 812 is 0.6m, the outer diameter of the catalyst pre-lifting section 811 is 0.6m, and the outer diameter of the liquid hydrocarbon reaction section 812 is 0.7m.

[0138] The reactant post-treatment unit 82 comprises a settler 821 and a regenerator (not labeled in Fig. 1). The upper part of the settler 821 is provided with a gas-solid separation system 8211 for separating the catalyst from the oil gas. The lower part of the settler 821 is provided with a stripping system 8212 for stripping the catalyst separated from the gas-solid separation system 8211. The top of the settler 821 is provided with a gas outlet 8213, and the bottom is provided with a catalyst outlet 8214. The top of the settler 821 is provided with a gas collecting device 8215 at the gas outlet 8213 for collecting the oil gas separated by the gas-solid separation system 8211 and the oil gas stripped by the stripping system 8212.

[0139] The top end of the light hydrocarbon reaction section 812 extends into the settler 821 from the bottom end of the settler 821 and is connected to the feed port of the gas-solid separation system 8211. The gas outlet 8213 of the settler 821 is connected to the oil gas outlet line 84. The catalyst outlet 8214 of the settler 821 is connected to the feed port of the regenerator, and the catalyst outlet of the regenerator is connected to the catalyst feed inclined pipe 83, so that the catalyst after the stripping treatment in the stripping system 8212 enters the regenerator for regeneration treatment, and the catalyst after the regeneration treatment in the regenerator enters the catalyst pre-lifting section 811 through the catalyst feed inclined pipe 83 for reuse.

[0140] The present comparative example also provides a light hydrocarbon catalytic cracking method, which is carried out using the light hydrocarbon catalytic cracking device provided by the present comparative example, and specifically comprises the following steps:

[0141] 1) The pre-lifting medium (water vapor) enters the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81 from the bottom end of the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81. In the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81, the pre-lifting medium contacts the high-temperature catalyst (its composition and properties are shown in Table 2) entering the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81, fluidizes the catalyst, and makes the catalyst flow along the light hydrocarbon treatment pipe 81.

[0142] The gaseous light hydrocarbon raw material (its composition is shown in Table 3) enters the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 from the gaseous hydrocarbon feed port at the bottom end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81. In the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81, the gaseous light hydrocarbon raw material contacts the catalyst flowing in the light hydrocarbon treatment pipe 81 and carries out a catalytic cracking reaction.

[0143] 2) The catalytic cracking reaction mixture fluid in the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 enters the reactant post-treatment unit 5 for post-treatment from the top end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81;

[0144] 3) in the post-reactant treatment unit 82, the mixture fluid from the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 is subjected to gas-solid separation by the settler 821 to separate the catalyst from the oil gas, the separated catalyst is subjected to stripping treatment, the oil gas after stripping treatment and the oil gas separated by the gas-solid separation are discharged from the settler 821 and enter the oil gas outlet pipeline 84, and the catalyst after stripping treatment is collected. The collected catalyst after stripping treatment enters the regenerator for air coke-burning regeneration, and the regenerated catalyst reenters the light hydrocarbon treatment tube 81 for recycling.

[0145] The operating parameters of each step in the present comparative example and the properties of the products collected by the oil gas outlet pipeline 84 are shown in Table 4.

[0146] Comparative Example 2

[0147] The present comparative example also provides a light hydrocarbon catalytic cracking method, which uses a light hydrocarbon catalytic cracking device identical to that of Comparative Example 1, and specifically includes the following steps:

[0148] 1) The pre-lifting medium (water vapor) enters the catalyst pre-lifting section 811 of the light hydrocarbon treatment tube 81 from the bottom end of the catalyst pre-lifting section 811 of the light hydrocarbon treatment tube 81. In the catalyst pre-lifting section 811 of the light hydrocarbon treatment tube 81, the pre-lifting medium contacts the high-temperature catalyst (its composition and properties are shown in Table 2) entering the catalyst pre-lifting section 811 of the light hydrocarbon treatment tube 81, fluidizes the catalyst, and makes the catalyst flow along the light hydrocarbon treatment tube 81.

[0149] The liquid light hydrocarbon feedstock (its composition is shown in Table 1) enters the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 from the liquid hydrocarbon feed inlet at the bottom end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 and is atomized. In the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81, the atomized liquid light hydrocarbon feedstock contacts the catalyst flowing in the light hydrocarbon treatment tube 81 and undergoes catalytic cracking reaction.

[0150] 2) The mixture fluid after the catalytic cracking reaction in the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 enters the post-reactant treatment unit 5 from the top end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 for post-treatment;

[0151] 3) in the post-reactant treatment unit 82, the mixture fluid from the light hydrocarbon reaction section 812 of the light hydrocarbon treatment tube 81 is subjected to gas-solid separation by the settler 821 to separate the catalyst from the oil gas, the separated catalyst is subjected to stripping treatment, the oil gas after stripping treatment and the oil gas separated by the gas-solid separation are discharged from the settler 821 and enter the oil gas outlet pipeline 84, and the catalyst after stripping treatment is collected. The collected catalyst after stripping treatment enters the regenerator for air coke-burning regeneration, and the regenerated catalyst reenters the light hydrocarbon treatment tube 81 for recycling.

[0152] The operating parameters designed for each step in the present comparative example and the properties of the products collected by the oil and gas outlet pipeline 84 are shown in Table 4.

[0153] Comparative Example 3

[0154] The present comparative example also provides a light hydrocarbon catalytic cracking method, which uses a light hydrocarbon catalytic cracking device identical to that of Comparative Example 1, and specifically includes the following steps:

[0155] 1) The pre-lifting medium (water vapor) enters the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81 from the bottom end of the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81. In the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81, the pre-lifting medium contacts the high-temperature catalyst (whose composition and properties are shown in Table 2) entering the catalyst pre-lifting section 811 of the light hydrocarbon treatment pipe 81 and fluidizes and flows along the light hydrocarbon treatment pipe 81.

[0156] The liquid light hydrocarbon feedstock (whose composition is shown in Table 1) enters the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 from the liquid hydrocarbon feed port at the bottom end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 and is atomized, and the gaseous light hydrocarbon feedstock (whose composition is shown in Table 3) enters the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 from the gaseous hydrocarbon feed port at the bottom end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81. In the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81, the gaseous light hydrocarbon feedstock and the atomized liquid light hydrocarbon feedstock contact the catalyst flowing in the light hydrocarbon treatment pipe 81 and undergo catalytic cracking reactions.

[0157] 2) The catalytic cracking reaction mixture fluid in the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 enters the post-treatment unit 5 from the top end of the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 for post-treatment;

[0158] 3) In the post-treatment unit 82, the mixture fluid from the light hydrocarbon reaction section 812 of the light hydrocarbon treatment pipe 81 is subjected to gas-solid separation using the settler 821 to separate the catalyst from the oil and gas, the separated catalyst is subjected to stripping treatment, the stripped catalyst is discharged together with the oil and gas obtained from the gas-solid separation from the settler 821 and enters the oil and gas outlet pipeline 84, and the stripped catalyst is collected. The collected stripped catalyst enters the regenerator for air calcination regeneration, and the regenerated catalyst reenters the light hydrocarbon treatment pipe 81 for recycling.

[0159] The operating parameters designed for each step in the present comparative example and the properties of the products collected by the oil and gas outlet pipeline 84 are shown in Table 4.

[0160] Table 1

[0161] Table 2

[0162] Table 3

[0163] Table 4

[0164] The light hydrocarbon catalytic cracking device provided by the present application is used for light hydrocarbon catalytic cracking in the light hydrocarbon catalytic cracking method provided by the present application, and the comparative example 1 to the comparative example 3 are used for light hydrocarbon catalytic cracking in the existing light hydrocarbon catalytic cracking device-light hydrocarbon catalytic cracking riser, and the comparative example 1 only uses a gaseous light hydrocarbon feed, the comparative example 2 only uses a liquid light hydrocarbon feed, and the comparative example 3 uses a combined feed of the gaseous light hydrocarbon and the liquid light hydrocarbon. The two light hydrocarbon feeds are used in the present application example 1 and the comparative example 3, and it can be seen from Table 4 that, compared with the comparative example 3 using the existing light hydrocarbon catalytic cracking device for light hydrocarbon catalytic cracking, the present application example 1 using the light hydrocarbon catalytic cracking device provided by the present application for light hydrocarbon catalytic cracking can significantly increase the processing amount of the light hydrocarbon, and can greatly increase the yield of the liquefied gas and the propylene, and can also increase the content of the aromatic hydrocarbon in the gasoline. This shows that the light hydrocarbon catalytic cracking device and method provided by the present application can significantly increase the processing amount of the light hydrocarbon and the light hydrocarbon cracking depth.

[0165] The present application example 2 is used for light hydrocarbon catalytic cracking under high severity operating conditions, and it can be seen from Table 4 that the present application example 2 still achieves a high yield of the liquefied gas and the propylene, and the content of the aromatic hydrocarbon in the gasoline is very high and can be further extracted.

[0166] The present application example 3 is used for light hydrocarbon catalytic cracking under low severity operating conditions after the device parameters are moderately modified, and it can be seen from Table 4 that the present application example 3 can moderately produce more liquefied gas and propylene, and the content of the olefin in the gasoline also has a large decrease.

[0167] It can be seen from the three examples that the operating parameters of the light hydrocarbon catalytic cracking device provided by the present application can be changed in a large range, the range of the process operating conditions is wide, and is suitable for moderately producing more liquefied gas, producing more liquefied gas, and maximizing the production of liquefied gas.

[0168] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A light hydrocarbon catalytic cracking apparatus, wherein, The device comprises a liquid hydrocarbon treatment pipe, a coarse separation device and a gaseous hydrocarbon diameter expansion reactor. The gaseous hydrocarbon diameter expansion reactor is a tubular shell with open top and bottom and is provided with a gaseous hydrocarbon feeding port at the bottom; the coarse separation device is a variable-diameter pipe comprising a bottom pipe section, a middle pipe section and a top pipe section from bottom to top, and the diameter of the top pipe section is smaller than that of the bottom pipe section and that of the middle pipe section; the coarse separation device is arranged in the gaseous hydrocarbon diameter expansion reactor, with the bottom end of the coarse separation device located in the middle or bottom pipe section of the gaseous hydrocarbon diameter expansion reactor and the top end of the coarse separation device located at the top end of the gaseous hydrocarbon diameter expansion reactor or extending out of the gaseous hydrocarbon diameter expansion reactor; the tail end of the liquid hydrocarbon treatment pipe is provided with a cyclone nozzle, and the tail end of the liquid hydrocarbon treatment pipe penetrates into the gaseous hydrocarbon diameter expansion reactor from the bottom opening of the gaseous hydrocarbon diameter expansion reactor and penetrates into the coarse separation device from the bottom end of the coarse separation device, and is located in the middle pipe section of the coarse separation device.

2. The apparatus of claim 1, wherein, The light hydrocarbon catalytic cracking device comprises a liquid hydrocarbon treatment pipe, a coarse separation device, a gaseous hydrocarbon diameter expansion reactor and a reactant riser. The gaseous hydrocarbon diameter expansion reactor is a tubular shell with open top and bottom and is provided with a gaseous hydrocarbon feeding port at the bottom; the coarse separation device is a variable-diameter pipe comprising a bottom pipe section, a middle pipe section and a top pipe section from bottom to top, and the diameter of the top pipe section is smaller than that of the bottom pipe section and that of the middle pipe section; the coarse separation device is arranged in the gaseous hydrocarbon diameter expansion reactor, with the bottom end of the coarse separation device located in the middle or bottom pipe section of the gaseous hydrocarbon diameter expansion reactor and the top end of the coarse separation device located at the top end of the gaseous hydrocarbon diameter expansion reactor or extending out of the gaseous hydrocarbon diameter expansion reactor; the tail end of the liquid hydrocarbon treatment pipe is provided with a cyclone nozzle, and the tail end of the liquid hydrocarbon treatment pipe penetrates into the gaseous hydrocarbon diameter expansion reactor from the bottom opening of the gaseous hydrocarbon diameter expansion reactor and penetrates into the coarse separation device from the bottom end of the coarse separation device, and is located in the middle pipe section of the coarse separation device.

3. The apparatus of claim 1 or 2, wherein, The liquid hydrocarbon treatment pipe is coaxial with the pipe section in the gaseous hydrocarbon diameter expansion reactor, the gaseous hydrocarbon diameter expansion reactor and the coarse separation device.

4. The apparatus of claim 1, wherein, The light hydrocarbon catalytic cracking device comprises a liquid hydrocarbon treatment pipe, a coarse separation device, a gaseous hydrocarbon diameter expansion reactor, a reactant riser and a reactant post-treatment unit. The gas hydrocarbon diameter expansion reactor is a tubular shell with open top and bottom, the bottom of the gas hydrocarbon diameter expansion reactor is provided with a gas hydrocarbon inlet, and the top opening of the gas hydrocarbon diameter expansion reactor is connected with the head end of the reactant riser; the coarse separation device is a variable-diameter pipe, which comprises a bottom pipe section, a middle pipe section and a top pipe section from bottom to top, and the pipe diameter of the top pipe section < the pipe diameter of the bottom pipe section < the pipe diameter of the middle pipe section; the coarse separation device is arranged in the gas hydrocarbon diameter expansion reactor, the bottom end of the coarse separation device is located in the middle or bottom pipe section of the gas hydrocarbon diameter expansion reactor, and the top end is located at the top end of the gas hydrocarbon diameter expansion reactor or the head of the reactant riser; the tail end of the liquid hydrocarbon treatment pipe is provided with a cyclone nozzle, the tail end of the liquid hydrocarbon treatment pipe penetrates into the inside of the gas hydrocarbon diameter expansion reactor from the bottom opening of the gas hydrocarbon diameter expansion reactor, and penetrates into the inside of the coarse separation device from the bottom end of the coarse separation device, and is located in the middle pipe section of the coarse separation device; the pipe section of the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor, the gas hydrocarbon diameter expansion reactor and the coarse separation device are coaxial; the reactant post-processing unit is connected with the tail end of the reactant riser.

5. The apparatus of any one of claims 1, 2, 4, wherein, the ratio of the inner diameter of the gas hydrocarbon diameter expansion reactor to the outer diameter of the middle pipe section of the coarse separation device and the outer diameter of the bottom pipe section of the coarse separation device is 1:0.4-0.8:0.15-0.3; the ratio of the outer diameter of the pipe section of the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor, the inner diameter of the middle pipe section of the coarse separation device and the inner diameter of the bottom pipe section of the coarse separation device is 1:2-3:1.2-1.4; the ratio of the inner diameter of the top pipe section of the coarse separation device, the inner diameter of the bottom pipe section of the coarse separation device and the inner diameter of the middle pipe section of the coarse separation device is 1:1.2-1.4:2-3; the length of the middle pipe section of the coarse separation device is 0.5-3m, preferably 1-2m; the length of the bottom pipe section of the coarse separation device is 0.5-7m, preferably 1-6m; the length of the top pipe section of the coarse separation device is 0.5-2m, preferably 0.6-1.5m.

6. The apparatus of any one of claims 1, 2, 4, wherein, The liquid hydrocarbon treatment pipe is provided with a catalyst pre-lifting section and a liquid hydrocarbon reaction section, the tail end of the catalyst pre-lifting section is connected with the head end of the liquid hydrocarbon reaction section, and the inner diameter of the catalyst pre-lifting section < the inner diameter of the liquid hydrocarbon reaction section; the head of the catalyst pre-lifting section is provided with a catalyst inlet and a pre-lifting medium inlet; the head of the liquid hydrocarbon reaction section is provided with a liquid hydrocarbon inlet; the pipe section of the liquid hydrocarbon treatment pipe in the gas hydrocarbon diameter expansion reactor is the liquid hydrocarbon reaction section.

7. The apparatus of claim 6, wherein, The liquid hydrocarbon inlet is provided with at least two material nozzles; each material nozzle is distributed at the same height interval on the side wall of the liquid hydrocarbon reaction section, each material nozzle is centrally symmetric, and the spray direction of each material nozzle is towards the central axis; the spray direction of each material nozzle forms a certain upward or downward angle with the cross section of the liquid hydrocarbon reaction section; the cross section of the liquid hydrocarbon reaction section refers to a plane perpendicular to the axis of the liquid hydrocarbon reaction section; wherein the spray direction of each material nozzle forms a downward angle with the cross section of the liquid hydrocarbon reaction section; The spray direction of each feed nozzle forms an angle of 5-60° with the cross section of the liquid hydrocarbon reaction section; preferably, the spray direction of the feed nozzle forms an angle of 15-45° with the cross section of the liquid hydrocarbon reaction section; The length of the catalyst pre-elevation section is 3-8 m, preferably 4-6 m; The length of the liquid hydrocarbon reaction section is 3-20 m, preferably 5-15 m; The ratio of the inner diameter of the catalyst pre-elevation section to the inner diameter of the liquid hydrocarbon reaction section is less than 1:1 and greater than or equal to 1:1.8, preferably 1:1.1-1.

4.

8. The device of any one of claims 1, 2, 4, wherein, The cyclone nozzle is provided with 2-6 fluid outlets of the same height and axially symmetric distribution; The direction of the fluid outlet of each cyclone nozzle is towards the pipe wall of the middle pipe section of the coarse separation device, and the angle between the direction of the fluid outlet of each cyclone nozzle and the pipe wall of the middle pipe section of the coarse separation device is the same and not equal to 90 degrees.

9. The device of claim 2 or 4, wherein, The ratio of the inner diameter of the reactant riser to the inner diameter of the gaseous hydrocarbon diameter expansion reactor is 1:2-5, preferably 1:3-4; The length of the reactant riser is 3-30 m, preferably 5-15 m.

10. The device of any one of claims 1, 2, 4, wherein, The bottom pipe section of the gaseous hydrocarbon diameter expansion reactor is provided with a gas distribution plate; The gas distribution plate is arranged in the gaseous hydrocarbon diameter expansion reactor in a manner that the center is high and the periphery is low, and the height difference between the center and the periphery of the gas distribution plate is 0.1-1 m, preferably 0.2-0.7 m; The diameter of the holes on the gas distribution plate is 5-60 mm, preferably 10-30 mm; The total opening rate on the gas distribution plate is 5%-50%, preferably 15%-30%; The height of the center of the gas distribution plate from the bottom end of the gaseous hydrocarbon diameter expansion reactor is 0.2-2 m, preferably 0.3-1 m; The height of the center of the gas distribution plate from the fluid outlet of the cyclone nozzle is 1-8 m, preferably 2-5 m; The height of the center of the gas distribution plate from the bottom end of the middle pipe section of the coarse separation device is 0.3-1 m.

11. The apparatus of claim 4, wherein, The reactant post-treatment unit comprises a settler and a regenerator; The upper part of the settler is provided with a gas-solid separation system, the feed inlet of the gas-solid separation system is connected with the tail end of the reactant riser, the gas-solid separation system is used to separate the catalyst from the oil gas, the lower part of the settler is provided with a stripping system to strip the catalyst separated from the gas-solid separation system, the top of the settler is provided with a gas outlet and the bottom is provided with a catalyst outlet; The catalyst outlet of the settler is connected with the feed inlet of the regenerator, and the catalyst outlet of the regenerator is communicated with the catalyst feed inlet of the catalyst pre-elevation section, so that the catalyst after stripping treatment in the stripping system enters the regenerator for regeneration treatment, and the catalyst after regeneration treatment in the regenerator is used in the catalyst pre-elevation section.

12. A light hydrocarbon catalytic cracking method, which is carried out by using the light hydrocarbon catalytic cracking device of any one of claims 1-11, comprising the following steps: 1) in the liquid hydrocarbon treatment pipe, the liquid light hydrocarbon feedstock is contacted with the catalyst to occur catalytic cracking reaction; 2) the mixture obtained after the catalytic cracking reaction in the liquid hydrocarbon treatment pipe is discharged from the cyclone nozzle of the liquid hydrocarbon treatment pipe into the middle pipe section of the coarse separation device and occurs cyclone, the catalyst in the mixture slides into the bottom pipe section of the coarse separation device and then enters the gas hydrocarbon diameter expansion reactor through the tail end of the coarse separation device, the oil gas in the mixture enters into the top pipe section of the coarse separation device and then enters the reactant riser through the top end of the coarse separation device; 3) the catalytic cracking reaction of the gaseous light hydrocarbon feedstock with the catalyst occurs in the dense phase section of the gaseous hydrocarbon upgrader reactor, and the mixture after the catalytic cracking reaction enters the reactor riser after passing through the space between the middle section and the top section of the pipe of the gaseous hydrocarbon upgrader reactor and the crude separation equipment; wherein, the gas hydrocarbon diameter expansion reactor dense phase section refers to the space between the middle pipe section of the coarse separation device in the gas hydrocarbon diameter expansion reactor and the bottom pipe section of the coarse separation device and the space between the gas hydrocarbon diameter expansion reactor and the liquid hydrocarbon treatment pipe; 4) the oil gas from step 2) and the mixture fluid from step 3) entering the reactant riser pass through the tail end of the reactant riser to enter the reactant post-processing unit for post-processing.

13. The method of claim 12, wherein, In step 1), in the liquid hydrocarbon treatment pipe, the liquid light hydrocarbon feedstock is contacted with the catalyst to occur catalytic cracking reaction, which includes: In the liquid hydrocarbon treatment pipe, the pre-lift medium entering the liquid hydrocarbon treatment pipe is contacted with the catalyst entering the liquid hydrocarbon treatment pipe and fluidizes the catalyst to flow along the liquid hydrocarbon treatment pipe; The liquid light hydrocarbon feedstock is atomized and enters the liquid hydrocarbon treatment pipe, contacted with the catalyst flowing in the liquid hydrocarbon treatment pipe and catalytic cracking reaction occurs; Wherein, the pre-lift medium is selected from water vapor or dry gas; Wherein, the temperature of the catalyst entering the liquid hydrocarbon treatment pipe before contacting with the pre-lift medium is 660-760℃; Wherein, the temperature of the mixture at the position of the cyclone nozzle is 560-650℃, preferably 580-630℃; Wherein, the apparent residence time of the oil gas in the liquid hydrocarbon treatment pipe is 0.8-2 seconds.

14. The method of claim 12, wherein, The reaction temperature of the catalytic cracking reaction of the gas light hydrocarbon feedstock with the catalyst in the gas hydrocarbon diameter expansion reactor dense phase section is 540-630℃, preferably 560-620℃.

15. The method of claim 12, wherein, The apparent residence time of the oil gas in the gas hydrocarbon diameter expansion reactor is 1.5-10 seconds, preferably 2-5 seconds.

16. The method of claim 12, wherein, The apparent linear velocity of the oil gas in the gas hydrocarbon diameter expansion reactor dense phase section is 0.7-1.4 m / s.

17. The method of claim 12, wherein, The method further includes: (5) in the reactant post-processing unit, the fluid from the reactant riser is subjected to gas-solid separation to separate the catalyst from the oil gas, the separated catalyst is subjected to stripping treatment, the oil gas after stripping treatment is discharged from the reactant post-processing unit together with the oil gas obtained by gas-solid separation and collected, and the catalyst after stripping treatment is collected; the catalyst after stripping treatment is collected is subjected to air coke-burning regeneration, and the regenerated catalyst is recycled into the liquid hydrocarbon treatment pipe.

18. The method of claim 12, wherein, In the process of step 3) that the gas light hydrocarbon feedstock is contacted with the catalyst to occur catalytic cracking reaction, water vapor not more than 8% of the mass of the gas light hydrocarbon feedstock is injected into the bottom of the gas hydrocarbon diameter expansion reactor, which is used to adjust the catalyst fluidization state and hydrocarbon partial pressure, so as to strengthen the cracking reaction path of the gas light hydrocarbon feedstock.

19. The method of claim 12, wherein, The method further comprises: injecting a quenching agent into the oil gas from step 2) and the mixture fluid from step 3) entering into the reactant riser, so as to control the temperature of the fluid in the reactant riser and thus control the reaction of the fluid in the reactant riser; The injection amount of the quenching agent is 1-10 wt% of the catalytic addition amount. The temperature of the quenching agent is normal temperature-200°C.

20. The method of claim 12, wherein, The liquid light hydrocarbon raw material comprises one or a mixture of two or more of olefin-rich gasoline, diesel oil, and light hydrocarbons with carbon atom number of 4-8; wherein the olefin-rich gasoline refers to gasoline with olefin content of 40 v% or more; The gaseous light hydrocarbon raw material is selected from olefin-rich low-carbon light hydrocarbons, wherein the olefin-rich low-carbon light hydrocarbons refer to low-carbon light hydrocarbons with olefin content of 40 v% or more, and the low-carbon light hydrocarbons have carbon atom number of 3-8, preferably 3-6.

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