A riser recycling device for preparing propylene from mixed aromatics

Abstract

The present invention relates to a riser recycling device for preparing propylene from mixed aromatics, comprising a riser reactor, a settler, a stripper and a regenerator; a lifting steam inlet is arranged at the lower end of the riser reactor; a first cyclone separator, a second cyclone separator, a first gas collecting chamber, a sealing plate and a stripper are arranged in the settler, the upper end of the riser reactor is extended into the settler and connected to the inlet of the first cyclone separator, the upper end of the first cyclone separator is connected to the second cyclone separator, the upper end of the second cyclone separator is connected to the first gas collecting chamber, the first gas collecting chamber is connected to the oil and gas outlet pipeline, the sealing plate is located in the lower part of the settler, and the stripper is located at the bottom of the settler; the bottom of the settler is connected to one end of the inclined tube to be generated, the other end of the inclined tube to be generated is connected to the side wall of the regenerator, and the bottom of the regenerator is connected to the riser reactor. The present invention has the beneficial effects of reducing the yield of coke and dry gas, and producing more propylene.

Description

Technical Field

[0001] The invention relates to a riser reactor, in particular to a riser recycling device for preparing propylene by mixing aromatic hydrocarbons, belonging to the technical field of petrochemical industry. Background Art

[0002] Propylene is the basic raw material for the three major synthetic materials. It is mainly used to produce polypropylene, acrylonitrile, isopropyl alcohol, acetone and propylene oxide, etc. It is used to produce a variety of important organic chemical raw materials, generate synthetic resins, synthetic rubber and a variety of fine chemicals, etc. Propylene is a very important basic chemical raw material. At present, the global propylene supply and demand relationship is tightening marginally.

[0003] From the perspective of technology, traditional steam cracking and catalytic cracking are still the main sources of propylene, accounting for 60%. Catalytic cracking is one of the processes of petroleum refining. It is a process in which heavy oil undergoes cracking reaction under the action of heat and catalyst to transform it into cracked gas, gasoline and diesel. The riser catalytic cracking unit is one of the most important secondary processing units in the oil refining industry. Its purpose is to improve the processing depth and product quality of crude oil and increase the output of light oil. In recent years, with the increase in the weight of catalytic cracking reaction raw materials and the continuous increase in the depth of catalytic cracking reaction, the yield of dry gas and coke has increased, resulting in a decrease in the yield of light oil. The applicant found in production practice that catalytic cracking hydrocarbons have poor stability and low cetane number, and cannot be sold directly as products. If they are recycled, some high-value-added propylene will be generated. Summary of the invention

[0004] The present invention mainly aims at the problem that the coke yield is high and the propylene yield is low when the existing mixed aromatics are recycled to propylene, and provides a riser recycling device for preparing propylene from mixed aromatics. The riser recycling device can reduce the coke and dry gas yields, and adopts a special catalyst for high-yield propylene to increase the yield of the target product propylene.

[0005] The purpose of the present invention is mainly achieved through the following solutions:

[0006] A riser recycling device for preparing propylene from mixed aromatics comprises a riser reactor, a settler, a stripper and a regenerator; a lifting steam inlet is arranged at the lower end of the riser reactor, and the upper end of the riser reactor extends into the settler; a first cyclone separator, a second cyclone separator, a first gas collecting chamber, a sealing plate and a stripper are arranged in the settler; the upper end of the riser reactor extends into the settler and is connected to the inlet of the first cyclone separator; an exhaust pipe at the upper end of the first cyclone separator is connected to the inlet of the second cyclone separator; an upper end outlet of the second cyclone separator is communicated with the first gas collecting chamber at the upper end of the settler; the top of the first gas collecting chamber is connected to an oil and gas outlet pipeline; the sealing plate is located in the lower part of the settler, and the feed leg outlets of the first cyclone separator and the second cyclone separator extend below the sealing plate; the stripper is located in the bottom of the settler; the bottom of the settler is connected to one end of a to-be-generated inclined tube, the other end of the to-be-generated inclined tube is connected to the side wall of the regenerator, and the bottom of the regenerator is communicated with the riser reactor.

[0007] By adopting the above technical scheme, the mixed aromatics enter the riser reactor, mix with the regenerated catalyst transported from the regenerator and gasified by the lifting steam, and enter the first cyclone separator and the second cyclone separator after completing the catalytic cracking reaction, so that the oil and gas are quickly separated from the catalyst. The separated oil and gas enter the first gas collecting chamber and are discharged to the subsequent product separation system through the oil and gas outlet pipeline. The separated catalyst to be regenerated enters the regenerator from the inclined tube to be regenerated to regenerate the deactivated catalyst to be regenerated, and the regenerated catalyst flows from the bottom of the regenerator to the riser reactor for recycling.

[0008] Preferably, the riser reactor comprises a pre-lifting section, a feed section, a catalytic cracking section and an introduction section which are sequentially connected from bottom to top; a catalyst mixing section is arranged at the upper portion of the pre-lifting section, a plurality of feed nozzles with openings facing downwards are arranged on the feed section, an expansion section is arranged at the upper portion of the catalytic cracking section, and a quenching agent inlet is arranged at the lower portion of the expansion section.

[0009] By adopting the above technical scheme, the catalyst mixing section can ensure that the regenerated catalyst is completely gasified, the expansion section can increase the catalyst-oil ratio of this section, and the quenching agent inlet is used to introduce the quenching agent to reduce the reaction temperature of the expansion section, thereby inhibiting secondary reactions.

[0010] Preferably, a third cyclone separator is provided on the introduction section, the inlet and gas phase outlet of the third cyclone separator are connected on the introduction section, and the liquid phase outlet of the third cyclone separator is connected to the catalyst mixing section through a pipeline.

[0011] By adopting the above technical scheme, the reacted oil agent enters the third cyclone separator from the inlet section to separate the semi-regenerated catalyst from the oil and gas. After the semi-regenerated catalyst comes out from the material leg at the bottom of the third cyclone separator, it flows to the catalyst mixing section and mixes with the regenerated catalyst, so that the reactant-oil ratio is increased and the catalytic cracking effect is improved. The separated oil and gas are sent to the first cyclone separator.

[0012] Preferably, the diameter of the diameter expansion section is 2-3 times the diameter of the introduction section, and the diameter of the diameter expansion section is larger than the diameter of the catalyst mixing section.

[0013] By adopting the above technical solution, the expansion section can suppress over-cracking and thermal cracking reactions at the top thereof, and can also ensure that the reaction time of the upper and middle part of the expansion section is prolonged at a lower reaction temperature.

[0014] Preferably, a sealed steam pipe and an oil and gas introduction pipe are also provided in the settler; the sealed steam pipe is an annular pipe which is sleeved on the outer side of the first gas collecting chamber, and a steam nozzle is opened on its lower end face; a plurality of oil and gas introduction pipes are provided, and the lower ends of the oil and gas introduction pipes extend below the sealing plate, and the upper ends of the oil and gas introduction pipes are connected to the exhaust pipe at the upper end of the first cyclone separator.

[0015] By adopting the above technical solution, the sealed steam pipe emits steam through the steam nozzle, and the steam fills the space above the sealing plate of the settler, thereby preventing the oil gas or catalyst from sticking to the inner wall of the settler and forming coke. In addition, the oil gas below the sealing plate is stripped by the stripper and quickly enters the exhaust pipe of the first cyclone separator through the oil and gas inlet pipe.

[0016] Preferably, there are gaps between the feed leg of the first cyclone separator, the feed leg of the second cyclone separator and the oil and gas inlet pipe and the sealing plate.

[0017] By adopting the above technical solution, excessive pressure in the space above the sealing plate in the settler can be avoided, thereby ensuring the normal operation of the device.

[0018] Preferably, a second air collecting chamber and a fourth cyclone separator are provided in the regenerator, a gas phase outlet of the fourth cyclone separator is communicated with the second air collecting chamber, and a regeneration flue gas duct is connected to the upper end of the second air collecting chamber.

[0019] By adopting the above technical solution, the catalyst to be regenerated is regenerated through the regenerator, the flue gas carrying the catalyst is separated from the catalyst through the fourth cyclone separator, and the clean flue gas is discharged to the second air collecting chamber through the top outlet of the fourth cyclone separator, and is discharged to the flue gas recovery system through the second air collecting chamber to recover the heat of the flue gas.

[0020] Preferably, the bottom of the regenerator is connected to the riser reactor through a degassing tank; a first regeneration inclined tube is connected between the bottom of the regenerator and the degassing tank, a second regeneration inclined tube is connected between the bottom of the degassing tank and the catalyst mixing section of the riser reactor, and the top of the degassing tank is connected to the lower part of the regenerator through a flue gas reflux pipe.

[0021] By adopting the above technical solution, the degassing tank is used to remove the oxygen-containing gas adsorbed and carried by the regenerated catalyst.

[0022] Preferably, an air distributor is provided at the lower inner portion of the regenerator, and an external heat exchanger is provided at the outer side of the regenerator.

[0023] By adopting the above technical solution, the air distributor is used to ensure that the burning air can be evenly distributed along the entire bed when entering the regenerator. The heat released by the regeneration and burning of the catalyst to be regenerated in the regenerator far exceeds the heat balance requirements of the regenerator and the settler, and an external heat extractor is required to remove the excess heat and make full use of the heat.

[0024] Preferably, a cooling medium inlet is provided at the lower portion of the external heat exchanger, and a cooling medium outlet is provided at the upper portion of the external heat exchanger.

[0025] By adopting the above technical solution, the cooling medium enters from the lower end of the external heat exchanger and is discharged from the upper end after heat exchange with the regenerated catalyst, thereby ensuring heat exchange efficiency.

[0026] Therefore, the present invention has the following advantages:

[0027] (1) The catalyst mixing section is arranged at the upper part of the pre-lifting section of the present invention, which can ensure that the regenerated catalyst and the semi-regenerated catalyst in the catalyst mixing section have sufficient buffer space, which can not only reduce the pressure fluctuation of the second regeneration inclined pipe, but also eliminate the effect of its horizontal force and eliminate the deviation caused by the S-shaped motion trajectory;

[0028] (2) The catalytic cracking section of the present invention is provided with an expanded diameter section at the top, which can suppress over-cracking and thermal cracking reactions at the top and ensure that the reaction time is prolonged at a lower reaction temperature in the middle and upper part of the expanded diameter section;

[0029] (3) The first cyclone separator and the second cyclone separator of the present invention are directly connected, which can ensure that there is almost no catalyst in the oil and gas discharged to the first gas collecting chamber;

[0030] (4) The settler of the present invention is provided with a sealing plate, a sealing steam pipe and an oil and gas introduction pipe. The sealing steam pipe discharges steam through a steam nozzle and fills the space above the sealing plate of the settler with steam to prevent the catalyst from adhering to the inner wall of the settler and forming coke. In addition, the oil and gas below the sealing plate are stripped by the stripper and then quickly enter the exhaust pipe of the first cyclone separator through the oil and gas introduction pipe;

[0031] (5) The external heat exchanger is arranged outside the regenerator of the present invention, which can ensure that the heat released by the regeneration and burning of the catalyst to be regenerated in the regenerator far exceeds the heat balance requirement of the regenerator and the settler, and fully utilizes the excess heat taken out by the external heat exchanger, and can also reduce the dry gas yield;

[0032] (6) The present invention is provided with a degassing tank for removing the oxygen-containing gas adsorbed and carried by the regenerated catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention.

[0034] Illustration: 1-lift pipe reactor, 2-settler, 3-stripper, 4-regenerator, 5-lift steam inlet, 6-first cyclone separator, 7-second cyclone separator, 8-first gas collecting chamber, 9-sealing plate, 10-exhaust pipe, 11-oil and gas outlet pipeline, 12-waiting inclined pipe, 13-pre-lift section, 14-feed section, 15-catalytic cracking section, 16-introduction section, 17-catalyst mixing section, 18-feed spray Nozzle, 19-expanded section, 20-quenching agent inlet, 21-third cyclone separator, 22-sealed steam pipe, 23-oil and gas inlet pipe, 24-second air collecting chamber, 25-fourth cyclone separator, 26-regeneration flue gas duct, 27-degassing tank, 28-first regeneration inclined pipe, 29-second regeneration inclined pipe, 30-flue gas reflux pipe, 31-air distributor, 32-external heat extraction pipe, 33-coolant inlet, 34-coolant outlet. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0036] like Figure 1 As shown, the present invention provides a technical solution, a riser recycling device for preparing propylene from mixed aromatics, which consists of a riser reactor 1, a settler 2, a regenerator 4 and a degassing tank 27.

[0037] The riser reactor 1 comprises a pre-lifting section 13, a feed section 14, a catalytic cracking section 15 and an introduction section 16 which are sequentially connected from bottom to top; a lifting steam inlet 5 is arranged at the lower end of the pre-lifting section 13, and a catalyst mixing section 17 is arranged at the upper part of the pre-lifting section 13; two feed nozzles 18 with openings facing downward are evenly arranged along the axial circumference of the feed section 14; an expansion section 19 is arranged at the upper part of the catalytic cracking section 15, and a quenching agent inlet 20 is arranged at the lower part of the expansion section 19; an introduction section 16 is provided; A third cyclone separator 21 is arranged on the section 16, the inlet and gas phase outlet of the third cyclone separator 21 are connected to the introduction section 16, and the liquid phase outlet of the third cyclone separator 21 is connected to the catalyst mixing section 17 through a pipeline; the diameters of the lower part of the pre-lifting section 13, the feed section 14, the lower part of the catalytic cracking section 15 and the introduction section 16 are equal, and the diameter of the expansion section 19 is 2.5 times the diameter of the introduction section 16, and the diameter of the catalyst mixing section 17 is 1.5 times the diameter of the introduction section 16.

[0038] The settler 2 is provided with a first cyclone separator 6, a second cyclone separator 7, a first gas collecting chamber 8, a sealing plate 9, a stripper 3, a sealed steam pipe 22 and an oil and gas introduction pipe 23. The introduction section 16 at the upper end of the riser reactor 1 extends into the settler 2 and is connected to the inlet of the first cyclone separator 6. The exhaust pipe 10 at the upper end of the first cyclone separator 6 is connected to the inlet of the second cyclone separator 7. The upper outlet of the second cyclone separator 7 is connected to the first gas collecting chamber 8 at the upper end of the settler 2. The top of the first gas collecting chamber 8 is connected to the oil and gas outlet pipeline 11. The sealing plate 9 is located in the settler 2. In the lower inner part, the sealed steam pipe 22 is an annular tube sleeved on the outside of the first air collecting chamber 8, and a steam nozzle is opened on its lower end face. The oil and gas introduction pipe 23 is evenly distributed inside the settler 2. The leg outlets of the first cyclone separator 6 and the second cyclone separator 7 and the lower ends of the oil and gas introduction pipe 23 extend below the sealing plate 9. There are gaps between the leg of the first cyclone separator 6, the leg of the second cyclone separator 7 and the oil and gas introduction pipe 23 and the sealing plate 9. The upper ends of the oil and gas introduction pipes 23 are connected to the exhaust pipe 10 at the upper end of the first cyclone separator 6; the stripper 3 is located at the bottom of the settler 2.

[0039] The side wall of the regenerator is connected to the bottom of the settler 2 through the inclined pipe 12 to be regenerated. The regenerator 4 is provided with a second air collecting chamber 24, a fourth cyclone separator 25 and an air distributor 31. The fourth cyclone separator 25 adopts a two-stage cyclone separator connected in series, and its gas phase outlet is connected to the second air collecting chamber 24. The upper end of the second air collecting chamber 24 is connected to the regeneration flue gas duct 26; an external heat exchanger 32 is provided on the outside of the regenerator 4, a cooling medium inlet 33 is provided at the lower part of the external heat exchanger 32, and a cooling medium outlet 34 is provided at the upper part of the external heat exchanger 32.

[0040] The degassing tank is connected to the bottom of the regenerator through a first regeneration inclined pipe 28, a second regeneration inclined pipe 29 is connected between the bottom of the degassing tank 27 and the catalyst mixing section 17 of the riser reactor 1, and the top of the degassing tank 27 is connected to the lower part of the regenerator 4 through a flue gas reflux pipe 30.

[0041] The reaction process of the riser recycling device for preparing propylene from mixed aromatics according to the present invention is as follows: the catalyst transported from the degassing tank 27 and the third cyclone separator 21 enters the catalyst mixing section 17, is lifted and gasified by the lifting steam entering the lifting steam inlet 5; the mixed aromatics are sprayed into the introduction section 6 after being atomized from the feed nozzle 9, mixed with the above-mentioned gasified catalyst and enter the introduction section 16 after completing the reaction in the catalytic cracking section 15; the oil after the reaction enters the third cyclone separator 21 from the introduction section 16, and the third cyclone separator 2 1 separates the semi-regenerated catalyst from the oil and gas. After the semi-regenerated catalyst comes out from the feed leg at the bottom of the third cyclone separator 21, it flows to the catalyst mixing section 17 to mix with the regenerated catalyst, so that the reactant-oil ratio is increased and the catalytic cracking effect is improved. The separated oil and gas are sent to the first cyclone separator 6 and the second cyclone separator 7. The first cyclone separator 6 and the second cyclone separator 7 quickly separate the oil and gas from the catalyst. After separation by the first cyclone separator 6 and the second cyclone separator 7, almost all the catalyst in the oil and gas is discharged from the feed leg to the stripper 19. The separated oil and gas enter the first gas collecting chamber 8, and are discharged to the subsequent product separation system through the oil and gas outlet pipeline 11 at the top of the first gas collecting chamber 8; the sealed steam pipe 22 gives steam through the steam nozzle, and the steam fills the space above the sealing plate 9 in the settler 2 to prevent the catalyst from sticking to the inner wall of the settler 2 and forming coke. In addition, the oil and gas below the sealing plate are stripped by the stripper 3 and quickly enter the exhaust pipe 10 of the first cyclone separator 6 through the oil and gas introduction pipe 23, and then enter the second cyclone separator 7 for oil and gas separation; the waiting oil and gas in the settler 2 The raw catalyst enters the regenerator 4 through the regenerated inclined pipe 12, and the high-temperature steam sprayed by the air distributor 31 burns the coke on the regenerated catalyst to regenerate the deactivated regenerated catalyst and form a regenerated catalyst. The regenerated catalyst is cooled by the external heat exchanger 32. The cooled regenerated catalyst enters the degassing tank 27 through the first regeneration inclined pipe 28 to remove the oxygen-containing gas adsorbed and carried by the regenerated catalyst. The degassed regenerated catalyst is then returned to the catalyst mixing section 17 of the riser reactor 1 through the second regeneration inclined pipe 29 for recycling.

[0042] The present invention uses a new petroleum catalyst R-MGOO-MF / E catalyst dedicated to high propylene production in the catalytic cracking process, which can further reduce the coke yield, maintain a more ideal product distribution, and increase the yield of the target product propylene; in the mixed aromatics recycling process, by adjusting the reaction temperature, changing the proportion of reactants in the feed system, the content of propylene in the cracked liquefied gas is increased. Through experiments, it is found that when the catalyst-oil ratio of the present invention is 4.5, the reaction time is 3.5 seconds, and the reaction temperature is 535°C, the proportion of propylene with a dry point of 190°C generated by cracking is 20.08%, while maintaining the distribution of the remaining product proportions, the proportion of propylene is increased by 9.64% compared with the existing propylene proportion, which is of great significance for the research on the process and device for high propylene production.

[0043] It should be understood that this embodiment is only used to illustrate the present invention and is not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A riser recycling device for preparing propylene from mixed aromatics, characterized in that: The riser recycling device comprises a riser reactor (1), a settler (2), a stripper (3) and a regenerator (4); a lifting steam inlet (5) is arranged at the lower end of the riser reactor (1), and the upper end of the riser reactor (1) extends into the settler (2); a first cyclone separator (6), a second cyclone separator (7), a first gas collecting chamber (8), a sealing plate (9) and the stripper (3) are arranged in the settler (2); the upper end of the riser reactor (1) extends into the settler (2) and is connected to the inlet of the first cyclone separator (6); an exhaust pipe (10) at the upper end of the first cyclone separator (6) is connected to the inlet of the second cyclone separator (7); The first cyclone separator (6) and the second cyclone separator (7) are connected to the first gas collecting chamber (8) at the upper end of the settler (2); the top end of the first gas collecting chamber (8) is connected to the oil and gas outlet pipeline (11); the sealing plate (9) is located at the lower part of the settler (2); and the feed leg outlets of the first cyclone separator (6) and the second cyclone separator (7) extend below the sealing plate (9); the stripper (3) is located at the bottom of the settler (2); the bottom of the settler (2) is connected to one end of the inclined tube to be generated (12); the other end of the inclined tube to be generated (12) is connected to the side wall of the regenerator (4); and the bottom of the regenerator (4) is connected to the riser reactor (1); The riser reactor (1) comprises a pre-lifting section (13), a feed section (14), a catalytic cracking section (15) and an introduction section (16) which are sequentially connected from bottom to top; a catalyst mixing section (17) is arranged at the top of the pre-lifting section (13); a plurality of feed nozzles (18) with openings facing downward are arranged at the feed section (14); an expansion section (19) is arranged at the top of the catalytic cracking section (15); and a quenching agent inlet (20) is arranged at the bottom of the expansion section (19); A third cyclone separator (21) is provided on the introduction section (16); an inlet and a gas phase outlet of the third cyclone separator (21) are connected to the introduction section (16); a liquid phase outlet of the third cyclone separator (21) is connected to the catalyst mixing section (17) via a pipeline; the diameter of the expanded diameter section (19) is 2 to 3 times the diameter of the introduction section (16), and the diameter of the expanded diameter section (19) is greater than the diameter of the catalyst mixing section (17).

2. A riser recycling device for preparing propylene from mixed aromatics according to claim 1, characterized in that: A sealed steam pipe (22) and an oil and gas introduction pipe (23) are also provided in the settler (2); the sealed steam pipe (22) is an annular pipe sleeved outside the first gas collecting chamber (8), and a steam nozzle is provided on its lower end surface; a plurality of oil and gas introduction pipes (23) are provided, and the lower ends of the oil and gas introduction pipes (23) extend below the sealing plate (9), and the upper ends of the oil and gas introduction pipes (23) are connected to the exhaust pipe (10) at the upper end of the first cyclone separator (6).

3. A riser recycling device for preparing propylene from mixed aromatics according to claim 2, characterized in that: There are gaps between the feed leg of the first cyclone separator (6), the feed leg of the second cyclone separator (7), and the oil and gas introduction pipe (23) and the sealing plate (9).

4. A riser recycling device for preparing propylene from mixed aromatics according to claim 1, characterized in that: The regenerator (4) is provided with a second air collecting chamber (24) and a fourth cyclone separator (25); a gas phase outlet of the fourth cyclone separator (25) is communicated with the second air collecting chamber (24), and a regeneration flue gas duct (26) is connected to the upper end of the second air collecting chamber (24).

5. A riser recycling device for preparing propylene from mixed aromatics according to claim 4, characterized in that: The bottom of the regenerator (4) is connected to the riser reactor (1) via a degassing tank (27); a first regeneration inclined tube (28) is connected between the bottom of the regenerator (4) and the degassing tank (27); a second regeneration inclined tube (29) is connected between the bottom of the degassing tank (27) and the catalyst mixing section (17) of the riser reactor (1); and the top of the degassing tank (27) is connected to the lower part of the regenerator (4) via a flue gas reflux pipe (30).

6. A riser recycling device for preparing propylene from mixed aromatics according to claim 4, characterized in that: An air distributor (31) is provided at the lower inner portion of the regenerator (4), and an external heat collector (32) is provided at the outer side of the regenerator (4).

7. A riser recycling device for preparing propylene from mixed aromatics according to claim 6, characterized in that: A cooling medium inlet (33) is provided at the lower portion of the external heat exchanger (32), and a cooling medium outlet (34) is provided at the upper portion of the external heat exchanger (32).

Images