Separation device and process for catalytic cracking products

Abstract

The invention discloses a catalytic cracking product separation device and process, the device comprises a reactor for preparing olefin through catalytic cracking, a chiller for cooling the reactor product and a quenching oil tower for fractionating the product passing through the chiller, the feed port of the chiller is connected with the discharge port of the reactor, and the feed port of the chiller is connected with the discharge port of the reactor. The bottom of the quenching oil tower is connected with a discharge hole of the chiller; the device further comprises a wax oil tank used for receiving external wax oil, a top discharge port of the wax oil tank is connected with the middle of the quenching oil tower, a bottom discharge port of the wax oil tank is connected with the bottom of the quenching oil tower, and bottom effluent of the wax oil tank serves as a circulating medium of the quenching oil tower. In the invention, the chiller can properly cool the reaction oil gas, and the cooled reaction oil gas enters the quenching oil tower for fractionation, so that the problem that the high-temperature oil gas is easy to precipitate and coke when medium-high pressure steam is generated can be solved, or the sudden boiling phenomenon caused by the fact that the high-temperature oil gas directly enters the quenching oil tower is avoided, the operation stability is improved, and the fractionation effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic cracking, and in particular relates to a separation device and process for catalytic cracking products. Background Art

[0002] In the field of petrochemicals, catalytic cracking mainly decomposes macromolecular compounds into smaller and more useful small molecule products through the action of catalysts. During the catalytic cracking process, due to the high temperature and high pressure conditions, some components in the oil and gas will undergo cracking reactions to generate precipitates that are easy to coke. For the quenching oil tower equipment used for cooling and fractionation, if the high-temperature oil and gas directly enter the quenching oil tower, the large amount of energy it carries will be transferred to the low-boiling point substances, making them in an unstable state or overheated state. After reaching a certain level, the low-boiling point substances suddenly vaporize and expand in volume, resulting in sudden boiling in the tower, which is easy to affect the stability of the device operation and the fractionation effect of the product.

[0003] In addition, during the operation of the quench oil tower, the operating parameters of the quench oil tower, such as the positional relationship, distance, flow rate, etc. of each outlet, and the control of the temperature at each processing node, will have an important impact on the separation effect of the quench oil tower. Since the control of the positional relationship, distance, flow rate, temperature and other parameters of each outlet is relatively complex, how to scientifically set the outlets of each fraction and reasonably optimize the relevant parameters at the outlets to improve the separation effect of the quench oil tower is still an important challenge.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art. In order to solve the problems that high-temperature oil and gas directly enter a quenching oil tower for cooling after catalytic cracking, which may lead to sudden boiling, or improper operating parameters of the quenching oil tower may lead to poor separation effect of the quenching oil tower, the present invention provides a separation device and process for catalytic cracking products.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a device for separating catalytic cracking products, which includes a reactor for preparing olefins by catalytic cracking, a chiller for cooling the reactor products, and a quenching oil tower for fractionating the products of the chiller, wherein the chiller feed port is connected to the reactor discharge port, and the quenching oil tower bottom is connected to the chiller discharge port.

[0008] Furthermore, the separation device for catalytic cracking products also includes a wax oil tank for receiving external wax oil. The top discharge port of the wax oil tank is connected to the middle of the quench oil tower, and the bottom discharge port of the wax oil tank is connected to the bottom of the quench oil tower, so that the effluent from the bottom of the wax oil tank is used as the circulating medium of the quench oil tower; the external wax oil can also be directly used as the cooling medium of the chiller.

[0009] Furthermore, the separation device of the catalytic cracking products also includes a heavy fuel oil tank for receiving the heavy components in the distillation products and a light fuel oil stripping tower for receiving and processing the light components in the distillation products. The heavy fuel oil tank is arranged below the wax oil tank, and the light fuel oil stripping tower is arranged above the wax oil tank.

[0010] Furthermore, the chiller uses wax oil and / or quenching circulating oil as a cooling medium, and the temperature of the reaction oil gas after being cooled by the chiller is 50-150°C.

[0011] Furthermore, wax oil is used as quenching oil, and wax oil from the outside enters the wax oil tank, and the outflow from the top of the wax oil tank enters the middle section of the quenching oil tower through the outlet at the top of the wax oil tank, and the outflow from the bottom of the wax oil tank enters the lower section of the quenching oil tower through the outlet at the bottom of the wax oil tank;

[0012] Preferably, the flow rate of the outflow from the top of the wax oil tank is 5t / h to 30t / h, and the outflow temperature is 180°C to 280°C;

[0013] Preferably, the flow rate of the effluent from the bottom of the wax oil tank is 5 t / h to 30 t / h, and the outflow temperature is 180°C to 280°C.

[0014] Furthermore, the quench oil circulated through the quench oil tower enters the quench oil steam generator through the quench oil outlet at the bottom of the quench oil tower, and the heat contained in the quench oil is used to generate medium-pressure steam, and the cooled quench oil is transported to the lower part of the quench oil tower for recycling;

[0015] Preferably, the temperature of the quench oil after cooling is 40 to 60°C;

[0016] Preferably, the quench oil after partial cooling is transported to the regenerator as fuel oil.

[0017] Furthermore, a light fuel oil extraction port is provided at the upper section of the quench oil tower, and the light fuel oil separated in the quench oil tower enters the light fuel oil stripping tower through the light fuel oil extraction port, and the flash point is controlled by the stripping steam, and the qualified light fuel oil is sent out through the discharge port at the bottom of the light fuel oil stripping tower;

[0018] Preferably, the light fuel oil production outlet is located higher than the position where the outflow from the top of the wax oil tank enters the quench oil tower;

[0019] Preferably, the gas phase in the light fuel oil stripping tower is returned to the quench oil tower from the discharge port at the top of the light fuel oil stripping tower to be fractionated again.

[0020] Usually, the light fuel oil extraction port is arranged in the middle and upper part of the quench oil tower to facilitate the smooth discharge of light fuel oil. At the same time, the location of the light fuel oil extraction port also needs to correspond to the feed port of the light fuel oil stripping tower to facilitate the transportation of light fuel oil.

[0021] Furthermore, a heavy fuel oil extraction port is provided in the middle and lower section of the quench oil tower, and the heavy fuel oil enters the heavy fuel oil tank from the heavy fuel oil extraction port. Part of the bottom material of the heavy fuel oil tank returns to the quench oil tower to provide liquid reflux for the bottom tray of the tower, and part of it is transported to the regenerator as fuel oil to provide heat;

[0022] Preferably, the top effluent of the heavy fuel oil tank and the top effluent of the wax oil tank together constitute the gas phase return tower material, which returns to the quench oil tower for fractionation;

[0023] Preferably, the location of the heavy fuel oil production outlet is lower than the location where the effluent from the top of the wax oil tank enters the quench oil tower.

[0024] Furthermore, a middle section circulating oil heat exchange unit is provided in the middle section of the quench oil tower, and the middle section circulating oil of the quench oil tower enters the middle section circulating oil heat exchange unit for heat exchange and cooling before returning to the quench oil tower;

[0025] Preferably, the position where the middle circulating oil of the quench oil tower enters the middle circulating oil heat exchange unit is higher than the position where the outflow from the top of the wax oil tank enters the quench oil tower;

[0026] Preferably, the temperature of the cooled middle-stage circulating oil returned to the quenching oil tower after being cooled by the middle-stage circulating oil heat exchange unit is 70-80°C.

[0027] The present invention also proposes a separation process of catalytic cracking products, which is applied to any of the above-mentioned separation devices for catalytic cracking products, and comprises the following steps:

[0028] The reaction raw materials enter the reactor for catalytic cracking reaction, and the catalytic cracking products after the reaction are cooled by the chiller;

[0029] The catalytic cracking products after cooling are fractionated through a quench oil tower to obtain light fuel oil, heavy fuel oil and tower top oil gas.

[0030] Preferably, the temperature of the reaction oil gas after being cooled by the chiller is 50-150°C.

[0031] Preferably, the flow rate of the outflow from the top of the wax oil tank is 5t / h to 30t / h, and the outflow temperature is 180°C to 280°C;

[0032] Preferably, the flow rate of the effluent from the bottom of the wax oil tank is 5 t / h to 30 t / h, and the outflow temperature is 180°C to 280°C.

[0033] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0034] 1. The chiller provided in the present invention can properly cool the reaction oil and gas, and the cooled reaction oil and gas enter the quench oil tower for fractionation, which can solve the problem that high-temperature oil and gas are easy to precipitate and coke when medium and high-pressure steam occurs, or avoid the sudden boiling phenomenon caused by high-temperature oil and gas directly entering the quench oil tower, thereby improving the operation stability of the device and enhancing the fractionation effect of the product;

[0035] 2. The quenching oil tower uses wax oil as the oil cooling medium to increase the temperature of the quenching oil tower kettle and generate medium-pressure steam to improve energy recovery;

[0036] 3. Several extraction ports are evenly arranged through the quenching oil tower. The quenching oil tower extracts the oil at different heights through the extraction ports according to the different densities of the fractions, following the principle of extracting at a high and low position with high density and extracting at a low and high position with low density. Thus, a variety of catalytic cracking products can be reasonably obtained on the basis of reducing the extraction energy, and the separation effect of the catalytic cracking products can also be improved.

[0037] 4. By reasonably setting the specific location and relative position, flow rate and extraction temperature of the extraction outlet, the separation efficiency can be improved and the operation stability of the quench oil tower can be improved;

[0038] 5. Reasonably match and set the flow rate of reaction oil and gas and cooling medium in the chiller, reduce the oil and gas temperature through the chiller, shorten the residence time of oil and gas in the pipeline, reduce coking, and also improve the separation efficiency.

[0039] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are part of the present invention and are used to provide a further understanding of the solutions of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0041] Figure 1 It is a process flow diagram of the separation process of the catalytic cracking product in the present invention.

[0042] Icons: 10, reaction raw materials; 12, reactor; 13, regenerator; 14, reactor output flow; 16, quencher; 17, cooling medium; 18, reaction oil and gas; 20, quench oil tower; 22, tower top oil and gas; 24, wax oil; 26, wax oil tank; 28, wax oil tank top effluent; 30, wax oil tank bottom effluent; 32, wax oil pump; 34, pump outlet wax oil; 36, quench oil; 38, quench oil spray pump; 40, pump outlet quench oil; 42, quench oil steam generator; 44, quench oil after cooling; 45, quench oil for cooling back to the tower; 46, cooling oil; 48, quench oil spray pump; 50, quench circulating oil; 52, fuel oil ; 54. Gasoline reflux; 56. Side-line light fuel oil; 58. Light fuel oil stripping tower; 60. Light fuel oil; 62. Light fuel oil stripping tower gas phase return tower material; 64. Stripping steam; 66. Mid-section circulating oil; 68. Mid-section circulating oil pump; 70. Mid-section circulating oil at pump outlet; 72. Mid-section circulating oil heat exchange unit; 74. Mid-section circulating oil after cooling; 76. Heavy fuel oil; 78. Heavy fuel oil tank; 80. Heavy fuel oil tank bottom effluent; 82. Heavy fuel oil pump; 84. Heavy fuel oil return tower material; 86. Heavy fuel oil tank top effluent; 88. Heavy fuel oil extracted material; 90. Gas phase return tower material.

[0043] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0045] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The present invention provides a separation device for catalytic cracking products, the device comprising a reactor 12 for catalytic cracking to prepare olefins, a chiller 16 for cooling the product of the reactor 12, and a quenching oil tower 20 for fractionating the product of the chiller 16, the feed port of the chiller 16 is connected to the discharge port of the reactor 12, and the bottom of the quenching oil tower 20 is connected to the discharge port of the chiller 16. The present invention eliminates the waste heat boiler at the discharge port of the reactor in the conventional process flow, and arranges the chiller 16 at the discharge port of the reactor 12, thereby solving the technical problem that high-temperature oil and gas in the conventional process flow are prone to coking on the tube bundle when medium- and high-pressure steam is generated, or directly enter the quenching oil tower to cause sudden boiling.

[0048] As a possible embodiment of the present invention, the device also includes a wax oil tank 26 for receiving external wax oil, the wax oil tank 26 is connected to the quenching oil tower 20, and the bottom effluent 30 of the wax oil tank is the circulating medium of the quenching oil tower 20; the external wax oil can also be directly used as the cooling medium of the chiller 16.

[0049] Furthermore, the top discharge port of the wax oil tank 26 is connected to the middle of the quench oil tower 20, and the bottom discharge port of the wax oil tank is connected to the bottom of the quench oil tower 20 via a wax oil pump 32, so that the effluent 30 from the bottom of the wax oil tank is used as the circulating medium of the quench oil tower. By setting wax oil as quench oil, the technical problems of low temperature of the quench oil tower kettle, low quality and low output of the generated steam caused by the conventional process flow using the high-temperature cracking product produced by the device as quench oil are solved.

[0050] As a possible embodiment of the present invention, the device also includes a heavy fuel oil tank 78 for receiving heavy components in the distillation product and a light fuel oil stripping tower 58 for receiving and processing light components in the distillation product. The heavy fuel oil tank 78 is arranged below the wax oil tank 26, and the light fuel oil stripping tower 58 is arranged above the wax oil tank 26.

[0051] Furthermore, the top of the heavy fuel oil tank 78 is connected to the top of the wax oil tank 26, and the material mixture is sent back to the upper part of the quench oil tower 20. The bottom of the heavy fuel oil tank 78 is connected to the lower part of the quench oil tower 20 and the regenerator 13, so that a part of the material provides liquid phase reflux for the bottom tower plate of the quench oil tower 20, and the rest is used as fuel oil to provide heat for the regenerator 13; the discharge port of the quench oil steam generator 42 is connected to the regenerator 13 via the quench oil spray pump 48. In the above scheme, the quench oil spray pump can be omitted according to actual production needs, so that the discharge port of the quench oil steam generator is directly connected to the regenerator.

[0052] The device also includes: a quench oil steam generator 42, whose feed port is connected to the quench oil outlet at the bottom of the quench oil tower, and whose discharge port is connected to the lower part of the quench oil tower 20. After the heat contained in the quench oil is used to generate medium-pressure steam, the cooled quench oil 44 is returned to the lower part of the quench oil tower 20 to form the return-tower cooling quench oil 45 for circulation by the quench oil tower; the bottom of the quench oil tower is connected to the feed port of the quench oil steam generator 42 via the quench oil spray pump 38 to realize the pressurized transportation of the quench oil.

[0053] The cooling oil 46 cooled by the quench oil steam generator 42 can also be pressurized by the quench oil spray pump 48 and sent to the regenerator 13 to provide heat; in addition, the cooling oil 46 cooled by the quench oil steam generator 42 can also be pressurized by the quench oil spray pump 48 to form quench circulating oil 50, and sent to the chiller 16 as a cooling medium 17.

[0054] As a possible embodiment of the present invention, the separation device of the catalytic cracking product also includes: a regenerator 13, which is connected to the reactor 12, and the regenerator 13 and the reactor 12 are arranged in a high-low or parallel manner, for catalyst char regeneration and providing reaction heat for the catalytic cracking reaction.

[0055] As an embodiment of the present invention, the quench oil tower 20 is also connected to a medium-circulation oil heat exchange unit 72 and a light fuel oil stripping tower 58 disposed above the wax oil tank 26, and the composition of the light fuel oil 60 is controlled by adjusting the stripping steam and the heat exchange heat.

[0056] The side-line light fuel oil 56 is produced from the quench oil tower 20 and enters the light fuel oil stripping tower 58. The flash point is controlled by stripping steam, and the qualified light fuel oil 60 is sent out. The middle-stage circulating oil 66 is extracted from the quench oil tower 20, and then returns to the quench oil tower 20 after heat exchange and cooling with other process media. The role of the middle-stage circulation is to remove excess heat and adjust the quality of the light fuel oil 60.

[0057] The embodiment of the present invention also provides a separation process of catalytic cracking products, comprising the following steps: the reaction raw material 10 enters the reactor 12 for catalytic cracking reaction, and the catalytic cracking products after the reaction are cooled by the chiller 16; the catalytic cracking products after cooling are fractionated by the quenching oil tower 20 to obtain light fuel oil 60, heavy fuel oil 76 and tower top oil gas 22. This embodiment eliminates the waste heat boiler at the discharge port of the reactor 12 in the conventional process flow, and sets the chiller 16 at the discharge port of the reactor 12, which solves the technical problem that the high-temperature oil and gas in the conventional process flow is easy to coke on the tube bundle when medium and high pressure steam is generated, or directly enters the quenching oil tower 20 to cause sudden boiling.

[0058] It should be noted that the reaction raw materials 10 include but are not limited to one or more of C4 alkanes, LPG, raffinate, reformed top oil, naphtha, jet fuel, diesel, and hydrocracking tail oil. The overhead oil and gas 22 includes water vapor and pyrolysis gasoline and the following pyrolysis gas light components.

[0059] Since the catalytic cracking products are prone to coking on the tube bundle or directly entering the quenching oil tower 20 at high temperature, causing sudden boiling, the catalytic cracking products need to be cooled by the chiller 16 before entering the quenching oil tower 20 for cooling and fractionation. Specifically, the chiller 16 is connected to the discharge port of the reactor 12 through the feed port, so as to timely cool the catalytic cracking products produced by the reactor 12; the chiller 16 is connected to the quenching oil tower 20 through the discharge port, so as to timely transport the cooled catalytic cracking products to the quenching oil tower 20 for fractionation.

[0060] As a possible embodiment of the present application, the chiller 16 uses wax oil and / or quenching circulating oil as a cooling medium; the temperature of the reaction oil gas after being cooled by the chiller 16 is 50-150°C.

[0061] The chiller 16 uses wax oil 24 and / or quenching circulating oil 50 as the cooling medium 17, which can effectively achieve industrial cooling. Preferably, the cooling medium 17 of the chiller 16 uses wax oil 24. By utilizing the advantages of wax oil 24 such as high melting point, good thermal conductivity, non-corrosiveness, good environmental protection, and easy handling, the catalytic cracking product can be cooled in time to obtain the cooled reaction oil gas 18.

[0062] Furthermore, the chiller 16 is a pipeline chiller, and the flow mode of the two streams of reaction oil gas 18 and quenching medium in the pipeline chiller can be countercurrent or parallel flow.

[0063] Preferably, the flow mode of the reaction oil gas 18 and the cooling medium 17 in the tubular chiller is countercurrent, and the countercurrent flow is conducive to the transfer of heat and can achieve higher heat exchange efficiency.

[0064] Matching the cooling medium flow rate with the reaction oil and gas flow rate: To achieve the best cooling effect, the cooling medium flow rate should match the reaction oil and gas flow rate. If the cooling medium flow rate is too large, the reaction oil and gas temperature may be too low, thus affecting the production process; if the cooling medium flow rate is too small, the reaction oil and gas may not be effectively cooled, resulting in excessively high temperatures. Therefore, it is necessary to determine the appropriate cooling medium flow rate based on the specific production situation and the properties of the reaction oil and gas.

[0065] The cooling time depends on the initial temperature of the reaction oil and gas, the target temperature, and the cooling capacity of the chiller. Generally speaking, the shorter the cooling time, the better, because this can improve production efficiency. However, too short a cooling time may cause the reaction oil temperature to be too high, thus affecting product quality. Therefore, it is necessary to balance the cooling time and cooling effect to ensure the optimal operation of the production process.

[0066] The design of the chiller will also affect the cooling effect and cooling time. For example, the size of the chiller, the layout of the cooling pipes, and the flow pattern of the cooling medium will affect the cooling capacity of the chiller. Therefore, when designing and selecting the chiller, these factors need to be considered to ensure that the chiller can provide the best cooling effect.

[0067] Operating conditions, such as the pressure, composition and ambient temperature of the reaction oil and gas, will also affect the cooling effect and cooling time of the chiller. Therefore, when determining the operating conditions of the chiller, these factors need to be considered to ensure that the chiller can adapt to different operating conditions.

[0068] As an embodiment of the present application, wax oil 24 is selected as the quenching oil of the quenching oil tower 20, the wax oil from the outside enters the wax oil tank 26, the effluent 28 from the top of the wax oil tank enters the middle section of the quenching oil tower 20 through the top discharge port of the wax oil tank 26, and the effluent 30 from the bottom of the wax oil tank enters the lower section of the quenching oil tower 20 through the discharge port at the bottom of the wax oil tank 26. The effluent 30 from the bottom of the wax oil tank is the quenching oil used for circulating and cooling in the quenching oil tower 20, and the effluent 28 from the top of the wax oil tank is various hydrocarbon compounds generated by the wax oil tank 26 during operation, and these gas mixtures and the effluent 86 from the top of the heavy fuel oil tank together constitute the gas phase return tower material 90. This embodiment uses wax oil 24 as quench oil to solve the technical problem that the conventional process uses the high-temperature cracking product produced by the device as the quench oil, and the high-temperature cracking product undergoes condensation and coking reactions to increase the viscosity of the quench oil, resulting in a low bottom temperature of the quench oil tower 20, and low quality and output of the generated steam.

[0069] Furthermore, a feed port is provided at the upper portion of the wax oil tank 26 to receive wax oil 24 from the outside, and a top discharge port of the wax oil tank 26 is connected to the middle portion of the quench oil tower 20 to transport the top effluent 28 of the wax oil tank, and a bottom discharge port of the wax oil tank 26 is connected to the bottom of the quench oil tower 20 via a wax oil pump 32, so that the bottom effluent 30 of the wax oil tank serves as a circulating medium of the quench oil tower 20.

[0070] Preferably, the flow rate of the outflow from the top of the wax oil tank is 5t / h to 30t / h, and the outflow temperature is 180°C to 280°C;

[0071] Preferably, the flow rate of the effluent from the bottom of the wax oil tank is 5 t / h to 30 t / h, and the outflow temperature is 180°C to 280°C.

[0072] In order to improve the utilization of the heat of the oil and gas at the bottom of the quenching oil tower 20, in the present embodiment, the quenching oil 36 circulated through the quenching oil tower 20 enters the quenching oil steam generator 42 through the quenching oil outlet at the bottom of the quenching oil tower, and the heat contained in the quenching oil 36 is used to generate medium-pressure steam, and the cooled quenching oil is transported to the lower part of the quenching oil tower 20 for recycling.

[0073] Specifically, the quenching oil 36 flows out from the outlet at the bottom of the quenching oil tower, enters the quenching oil steam generator 42 through the feed port of the quenching oil steam generator 42, and after the heat contained in the quenching oil 36 is used to generate medium-pressure steam, a part of the cooled quenching oil 44 returns to the lower part of the quenching oil tower 20 through the discharge port of the quenching oil steam generator 42 to form the return-tower cooling quenching oil 45 for circulation by the quenching oil tower 20; the other part is used as cooling oil 46 to be mixed with the heavy fuel oil extracted material 88 to form fuel oil, which provides heat for the operation of the regenerator 13.

[0074] Further optionally, the bottom of the quench oil tower 20 can be connected to the feed port of the quench oil steam generator 42 via the quench oil spray pump 38 to achieve pressurized delivery of the quench oil 36 and increase the delivery speed of the quench oil 36.

[0075] Preferably, the temperature of the quench oil 44 after cooling is 40 to 60°C;

[0076] Preferably, part of the cooled quench oil 44 is delivered to the regenerator 13 as fuel oil 52, thereby improving the utilization of the quench oil 36 and reducing the operating cost of the regenerator 13. Optionally, a quench oil pump 48 may be provided on the pipeline for delivering the cooled quench oil 44 to the regenerator 13 to realize pressurized delivery of the cooled quench oil 44 and improve delivery efficiency.

[0077] The quenching oil tower 20 is provided with a plurality of extraction ports to obtain the cooling fractionation product. The setting height of each extraction port is set according to the density and / or distillation height of the material to be processed. The position setting of the extraction port can change and affect the flow conditions inside the quenching oil tower 20. The reasonable position of the extraction port can improve the cooling efficiency, thereby reducing the adverse reactions of the cracking products and improving the product quality.

[0078] Specifically, a light fuel oil production outlet is provided at the upper section of the quenching oil tower 20. The light fuel oil 60 separated in the quenching oil tower 20 enters the light fuel oil stripping tower 58 through the light fuel oil production outlet. The flash point is controlled by the stripping steam, and the qualified light fuel oil 60 is delivered through the discharge port at the bottom of the light fuel oil stripping tower 58.

[0079] Furthermore, the gas phase in the light fuel oil stripping tower 58 is returned to the quench oil tower 20 from the discharge port at the top of the light fuel oil stripping tower 58 for further fractionation, which can fully save materials and avoid the loss of gas phase returning to the tower.

[0080] Furthermore, the position of the light fuel oil production outlet is higher than the position where the outflow from the top of the wax oil tank 26 enters the quenching oil tower 20, so that the production of light fuel oil is not affected by the wax oil tank 26, thereby improving the safety of the operation of the wax oil tank 26 and the light fuel oil stripping tower 58.

[0081] The light fuel oil extraction port will be arranged in the middle and upper part of the quench oil tower to facilitate the smooth discharge of light fuel oil. At the same time, the location of the light fuel oil extraction port also needs to correspond to the feed port of the light fuel oil stripping tower to facilitate the transportation of light fuel oil.

[0082] The light fuel oil stripping tower 58 is located above the wax oil tank 26, which can reduce the risk of fire and explosion. If the light fuel oil stripping tower 58 leaks or other situations occur, it will not directly affect the wax oil tank 26, reducing safety hazards. Secondly, it also makes better use of space, reduces floor space, and improves the rationality of the equipment layout.

[0083] Preferably, the extraction temperature of the light fuel oil extraction port is 55-65° C.; the flow rate at each outlet of the light fuel oil stripping tower 58 is 1.5-2.5 cubic meters per hour, and the temperature is 65-75° C. The reasonable light fuel oil extraction temperature, outlet flow rate and temperature proposed in this embodiment can ensure low-loss extraction of light fuel oil, thereby improving the separation effect of the reaction oil and gas 18 in the quenching oil tower 20.

[0084] A heavy fuel oil production port is provided in the middle and lower sections of the quenching oil tower 20, and the heavy fuel oil enters the heavy fuel oil tank 78 from the heavy fuel oil production port. Part of the bottom material of the heavy fuel oil tank 78 returns to the quenching oil tower 20 to provide liquid phase reflux for the bottom tower plate, and part of it is transported to the regenerator 13 as fuel oil to provide heat.

[0085] Preferably, the heavy fuel oil tank top effluent 86 and the wax oil tank top effluent 28 together constitute the gas phase return tower material 90, which returns to the quench oil tower 20 for fractionation.

[0086] Preferably, the location of the heavy fuel oil production port is lower than the location where the outflow 28 from the top of the wax oil tank enters the quench oil tower 20.

[0087] It should be further explained that the bottom of the heavy fuel oil tank 78 is connected to the lower part of the quench oil tower 20 and the regenerator 13 respectively through a heavy fuel oil pump 82, so that a part of the bottom effluent 80 of the heavy fuel oil tank is returned to the quench oil tower 20 as the heavy fuel oil return material 84, providing liquid phase reflux for the bottom tower plate of the quench oil tower 20 and assisting in adjusting the liquid level at the bottom of the distillation tower or the product distribution of the adjustment device; the remaining part of the bottom effluent 80 of the heavy fuel oil tank is used as fuel oil 52 to provide heat for the operation of the regenerator 13.

[0088] Furthermore, the top of the heavy fuel oil tank 78 is connected to the top discharge port of the wax oil tank 26, and the top outflow 86 of the heavy fuel oil tank is mixed with the top outflow 28 of the wax oil tank to obtain a gas phase return tower material 90, and the obtained gas phase return tower material 90 is sent to the upper part of the quenching oil tower 20, and is cooled and distilled again along with the material in the quenching oil tower 20.

[0089] Furthermore, the extraction temperature of the heavy fuel oil extraction port is 55-65° C.; the flow rate at each outlet of the heavy fuel oil tank 78 is 1.5-2.5 cubic meters per hour, and the temperature is 65-75° C. The extraction temperature, outlet flow rate and temperature of the heavy fuel oil proposed in this embodiment can ensure low-loss extraction of the heavy fuel oil, thereby improving the separation effect of the reaction oil and gas in the quenching oil tower 20.

[0090] As a possible embodiment of the present invention, the middle section of the quench oil tower 20 is also provided with a middle section circulating oil heat exchange unit 72. The middle section circulating oil 66 of the quench oil tower 20 enters the middle section circulating oil heat exchange unit 72 for heat exchange and cooling before returning to the quench oil tower 20.

[0091] Specifically, the middle circulating oil 66 generated by the fractionation of the quench oil tower 20 is pumped out by the middle circulating oil pump 68 to the middle circulating oil heat exchange unit 72, and after heat exchange and cooling with other process media in the middle circulating oil heat exchange unit 72, the cooled middle circulating oil 74 is obtained and returned to the quench oil tower 20. The function of the middle circulating oil 66 is to remove the excess heat generated during the fractionation process of the quench oil tower 20 and adjust the quality of the light fuel oil 60.

[0092] Furthermore, the position where the middle circulating oil of the quench oil tower 20 enters the middle circulating oil heat exchange unit 72 is higher than the position where the wax oil tank top outflow 28 enters the quench oil tower 20 .

[0093] Furthermore, the temperature of the cooled middle-stage circulating oil 74 returned to the quench oil tower 20 after being cooled by the middle-stage circulating oil heat exchange unit 72 is 70-80°C.

[0094] As an embodiment of the present invention, the separation process of the catalytic cracking product of the present invention also includes the treatment of the top oil gas 22 of the upper section of the quench oil tower 20, that is, the top of the quench oil tower 20 is provided with a top oil gas production outlet, and the top oil gas production outlet is connected to the transmission pipeline to output the top oil gas 22. After the top oil gas 22 is cooled, it is further separated and cooled through a water washing tower, wherein the top oil gas 22 components are water vapor and cracked gasoline and the cracked gas light components below. The output and treatment of the top oil gas 22 can avoid the top oil gas 22 being directly discharged into the atmosphere to cause environmental pollution.

[0095] Furthermore, a temperature sensor is provided at each outlet of the quenching oil tower 20, and the temperature of each outlet is monitored and adjusted in real time by the temperature sensor. The temperature sensor transmits the temperature of each outlet monitored and collected to the control system, and the control system can adjust the circulation speed of the cooling medium 17 and the output flow value of each outlet accordingly, thereby controlling the temperature of each outlet within the range of 55 to 65°C. Reasonable adjustment of the outlet temperature can improve the cooling efficiency, reduce the thermal cracking reaction of the oil product during the quenching process, and reduce the content of undesirable components in the product.

[0096] The separation process of the catalytic cracking products of the present invention also includes a catalyst regeneration process: the catalyst is burned and regenerated through the regenerator 13 and input into the reactor 12 to provide catalyst for the catalytic cracking of the reaction raw materials 10 and provide reaction heat for the catalytic cracking reaction in the reactor 12.

[0097] Furthermore, the reactor 12 is connected to a regenerator 13, and the regenerator 13 and the reactor 12 are arranged in a high-low or parallel manner.

[0098] The separation process of the catalytic cracking products of the present invention also includes gasoline reflux 54, specifically including introducing gasoline reflux 54 at the top of the quench oil tower 20, so that the product cooled by the quencher 16 undergoes mass and heat transfer with the quench oil, the intermediate circulating oil 66 and the gasoline to achieve fractional distillation of the product.

[0099] In the present invention, in the cavity of the quench oil tower 20, the product cooled by the quencher 16, that is, the reaction oil gas 18, is fed from the bottom and rises in the tower. The gasoline reflux 54 is introduced at the top of the tower. The rising reaction oil gas 18 and the refluxed quench oil 36, the middle circulating oil 66, and the gasoline are transferred on the tower plate for mass and heat transfer. The heavy components in the gas are condensed, and the light components in the liquid are vaporized. The heavy fuel oil 76 is separated from the lower part of the quench oil tower 20, and the light fuel oil 56 is produced by the side line for stripping. What is separated from the top of the tower is water vapor and cracked gasoline and the light components of cracked gas below it. The cooled top oil gas 22 enters the subsequent water washing tower for further separation and cooling.

[0100] Compared with the prior art, the present invention has the following beneficial technical effects after adopting the above embodiments:

[0101] The chiller provided in the present invention can properly cool the reaction oil and gas, and the cooled reaction oil and gas enter the quenching oil tower for fractionation, which can solve the problem that high-temperature oil and gas are easy to precipitate and coke when medium and high-pressure steam occurs, or avoid the sudden boiling phenomenon caused by high-temperature oil and gas directly entering the quenching oil tower, thereby improving the operation stability of the device and enhancing the fractionation effect of the product;

[0102] The quench oil tower uses wax oil as the oil cooling medium to increase the temperature of the quench oil tower kettle and generate medium-pressure steam to improve energy recovery and utilization;

[0103] The quenching oil tower is evenly provided with a number of extraction ports. The quenching oil tower performs high and low staggered extraction through each extraction port according to the different densities of the fractionated fractions, following the principle of high-density low-position extraction and low-density high-position extraction, thereby reasonably obtaining a variety of catalytic cracking products on the basis of reducing the extraction energy, and also improving the separation effect of the catalytic cracking products;

[0104] By reasonably setting the specific location and relative position, flow rate, and extraction temperature of the extraction outlet, the separation efficiency can be improved and the operating stability of the quench oil tower can be enhanced;

[0105] Reasonably match and set the flow rates of reaction oil and gas and cooling medium in the chiller, lower the oil and gas temperature through the chiller, shorten the residence time of oil and gas in the pipeline, reduce coking, and also improve separation efficiency.

[0106] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content suggested above without departing from the scope of the technical solution of the present invention. The implementation scheme in the above embodiment can also be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the solution of the present invention.

Claims

1. A separation device for catalytic cracking products, characterized in that: The device comprises a reactor for preparing olefins by catalytic cracking, a chiller for cooling the reactor product, and a quenching oil tower for fractionating the product passing through the chiller, wherein the chiller feed port is connected to the reactor discharge port, and the quenching oil tower bottom is connected to the chiller discharge port.

2. The separation device for catalytic cracking products according to claim 1, characterized in that: The device also includes a wax oil tank for receiving external wax oil, the top discharge port of the wax oil tank is connected to the middle of the quench oil tower, and the bottom discharge port of the wax oil tank is connected to the bottom of the quench oil tower, so that the effluent from the bottom of the wax oil tank is used as the circulating medium of the quench oil tower; the external wax oil can also be directly used as the cooling medium of the chiller.

3. The separation device for catalytic cracking products according to claim 1 or 2, characterized in that: The device also includes a heavy fuel oil tank for receiving heavy components in the distillation product and a light fuel oil stripping tower for receiving and processing light components in the distillation product; the heavy fuel oil tank is arranged below the wax oil tank, and the light fuel oil stripping tower is arranged above the wax oil tank.

4. The separation device for catalytic cracking products according to any one of claims 1 to 3, characterized in that: The chiller uses wax oil and / or quenching circulating oil as cooling medium.

5. The separation device for catalytic cracking products according to claim 4, characterized in that: Wax oil is used as quenching oil. Wax oil from the outside enters the wax oil tank. The outflow from the top of the wax oil tank enters the middle section of the quenching oil tower through the outlet at the top of the wax oil tank, and the outflow from the bottom of the wax oil tank enters the lower section of the quenching oil tower through the outlet at the bottom of the wax oil tank.

6. The separation device for catalytic cracking products according to claim 5, characterized in that: The quench oil circulated in the quench oil tower enters the quench oil steam generator through the quench oil outlet at the bottom of the quench oil tower, and the heat contained in the quench oil is used to generate medium-pressure steam, and the cooled quench oil is transported to the lower part of the quench oil tower for recycling; Preferably, the temperature of the quench oil after cooling is 40 to 60°C; Preferably, the quench oil after partial cooling is transported to the regenerator as fuel oil.

7. The separation device for catalytic cracking products according to any one of claims 1 to 6, characterized in that: The upper section of the quench oil tower is provided with a light fuel oil extraction port. The light fuel oil separated in the quench oil tower enters the light fuel oil stripping tower through the light fuel oil extraction port. The flash point is controlled by the stripping steam. The qualified light fuel oil is sent out through the discharge port at the bottom of the light fuel oil stripping tower. Preferably, the light fuel oil production outlet is located higher than the position where the outflow from the top of the wax oil tank enters the quench oil tower; Preferably, the gas phase in the light fuel oil stripping tower is returned to the quench oil tower from the discharge port at the top of the light fuel oil stripping tower to be fractionated again.

8. The separation device for catalytic cracking products according to any one of claims 1 to 7, characterized in that: A heavy fuel oil extraction port is provided in the middle and lower section of the quench oil tower. The heavy fuel oil enters the heavy fuel oil tank from the heavy fuel oil extraction port. Part of the bottom material of the heavy fuel oil tank returns to the quench oil tower to provide liquid reflux for the bottom tray of the tower, and part of it is transported to the regenerator as fuel oil to provide heat. Preferably, the top effluent of the heavy fuel oil tank and the top effluent of the wax oil tank together constitute the gas phase return tower material, which returns to the quench oil tower for fractionation; Preferably, the location of the heavy fuel oil production outlet is lower than the location where the effluent from the top of the wax oil tank enters the quench oil tower.

9. The separation device for catalytic cracking products according to any one of claims 1 to 8, characterized in that: The middle section of the quench oil tower is also provided with a middle section circulating oil heat exchange unit. The middle section circulating oil of the quench oil tower enters the middle section circulating oil heat exchange unit for heat exchange and cooling before returning to the quench oil tower. Preferably, the position where the middle circulating oil of the quench oil tower enters the middle circulating oil heat exchange unit is higher than the position where the outflow from the top of the wax oil tank enters the quench oil tower; Preferably, the temperature of the cooled middle-stage circulating oil returned to the quenching oil tower after being cooled by the middle-stage circulating oil heat exchange unit is 70-80°C.

10. A separation process for catalytic cracking products, characterized in that: The separation device for the catalytic cracking products according to any one of claims 1 to 9 comprises the following steps: The reaction raw materials enter the reactor for catalytic cracking reaction, and the catalytic cracking products after the reaction are cooled by the chiller; The catalytic cracking products after cooling are fractionated through a quench oil tower to obtain light fuel oil, heavy fuel oil and overhead oil gas; Preferably, the temperature of the reaction oil gas after being cooled by the chiller is 50-150°C; Preferably, the flow rate of the outflow from the top of the wax oil tank is 5t / h to 30t / h, and the outflow temperature is 180°C to 280°C; Preferably, the flow rate of the effluent from the bottom of the wax oil tank is 5 t / h to 30 t / h, and the circulation temperature is 180°C to 280°C.

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