Oxygen-enriched regenerative catalytic cracking system and regenerative catalytic cracking process

Abstract

An oxygen-enriched regenerative catalytic cracking system and regenerative catalytic cracking process, comprising: a second heat exchanger for heating normal-temperature air to preheated air through externally discharged flue gas; the first heat exchanger is used for heating the preheated air into heated air through high-temperature oxygen-deficient air; the preheating furnace is used for performing complete reaction heat release through the oxygen-enriched gas and the incompletely regenerated flue gas, heating the heated air to high-temperature air and generating exhaust flue gas; the oxygen permeable membrane reactor is used for separating the high-temperature air into high-temperature oxygen-deficient air and oxygen, and the oxygen and the incompletely regenerated flue gas are mixed and react to form oxygen-enriched gas; the catalytic cracking reactor is used for catalytically cracking raw oil through a catalyst; and the regenerator is used for carrying out incomplete reaction on the oxygen-enriched gas and the spent catalyst to generate incomplete regenerated flue gas containing CO and a regenerated catalyst. The invention aims to solve the problems that pollutants are generated and the heat efficiency is low in the operation process of a traditional heating furnace, and high-efficiency and low-emission operation of the heating furnace is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic cracking, in particular to an oxygen-rich regeneration catalytic cracking system and a regeneration catalytic cracking process. BACKGROUND

[0002] At present, the catalytic cracking system of a refinery usually adopts a conventional air regeneration technology, which has the disadvantages of low coke burning capacity, large amount of regeneration flue gas, and complex subsequent treatment process. In order to further improve the processing capacity of the catalytic cracking system, improve the product yield, reduce the emission of pollutants, and simplify the subsequent regeneration flue gas treatment process, the oxygen-rich regeneration catalytic cracking technology has a very broad prospect. However, due to the high cost and complex system of conventional low-temperature rectification technology, membrane separation technology, pressure swing adsorption technology, and chemical chain air separation technology, the development of the oxygen-rich regeneration catalytic cracking technology is restricted. SUMMARY

[0003] The present application aims to provide an oxygen-rich regeneration catalytic cracking system and a regeneration catalytic cracking process, which solve the problems of pollution and low thermal efficiency in the operation process of a traditional heating furnace, and realize efficient and low-emission operation of the heating furnace.

[0004] In order to solve the above technical problems, the specific scheme adopted by the present application is as follows: an oxygen-rich regeneration catalytic cracking system, comprising:

[0005] a second heat exchanger, which heats normal-temperature air to preheated air through exhaust flue gas;

[0006] a first heat exchanger, which heats the preheated air to heated air through high-temperature lean-oxygen air;

[0007] a pre-heating furnace, which heats the heated air to high-temperature air through complete reaction and heat release of oxygen-rich gas and incomplete regeneration flue gas, and generates exhaust flue gas;

[0008] an oxygen-permeable membrane reactor, which separates the high-temperature air into high-temperature lean-oxygen air and oxygen, and mixes and reacts the oxygen with the incomplete regeneration flue gas to form the oxygen-rich gas;

[0009] a catalytic cracking reactor, which catalytically cracks raw oil through a catalyst;

[0010] a regenerator, which provides the oxygen-rich gas for incomplete reaction with spent catalyst to generate incomplete regeneration flue gas containing CO and regenerated catalyst.

[0011] Preferably, the system further comprises a condensation separator, which is used to separate the exhaust flue gas through the second heat exchanger into H2O and CO2.

[0012] Preferably, the oxygen-permeable membrane reactor is of a plate-and-tube structure.

[0013] Preferably, the oxygen-permeable membrane reactor has a round tube-shaped oxygen-permeable membrane tube, the diameter of the oxygen-permeable membrane tube is 1-30 mm, the thickness of the oxygen-permeable membrane is 0.1-6 mm, and the tube spacing is 0.5-4 times the tube diameter.

[0014] Preferably, the working temperature of the oxygen-permeable membrane reactor is 400-1100℃, the pressure difference between the two sides of the oxygen-permeable membrane tube is 0-10 MPa, and the inner pressure of the oxygen-permeable membrane tube is not lower than the outer pressure of the oxygen-permeable membrane tube.

[0015] Preferably, the oxygen-permeable membrane of the oxygen-permeable membrane tube is of perovskite type, fluorite-perovskite type, fluorite-metal type or perovskite-metal type structure.

[0016] Preferably, the oxygen-permeable membrane of the oxygen-permeable membrane tube is a single-layer membrane or a multi-layer membrane.

[0017] An oxygen-enriched regeneration catalytic cracking process is performed on raw oil using any of the above oxygen-enriched regeneration catalytic cracking systems.

[0018] Preferably, the temperature, pressure and flow rate of the high-temperature air entering the oxygen-permeable membrane reactor are controlled to adjust the oxygen concentration in the oxygen-enriched gas.

[0019] Preferably, the volume concentration of oxygen in the oxygen-enriched gas is adjusted to 0-80%.

[0020] Preferably, the volume concentration of oxygen in the oxygen-enriched gas is adjusted to 25-30%.

[0021] Preferably, the oxygen-enriched gas entering the regenerator accounts for 70-95% of the total amount of oxygen-enriched gas.

[0022] Preferably, the incomplete regeneration flue gas entering the pre-heating furnace accounts for 5-30% of the total amount of incomplete regeneration flue gas. Advantages

[0023] First, the present application can improve the processing capacity of the catalytic cracking unit, change the product distribution, and improve the product yield. The oxygen-enriched regeneration catalytic cracking can greatly improve the coking capacity of the regenerator, further reduce the catalyst carbon content, improve the catalyst reaction activity, and improve the processing capacity of the catalytic cracking unit; at the same time, the product distribution is optimized, and the total liquid yield can be increased by 1-2%.

[0024] Second, the present application reduces the investment cost and operating cost of the regeneration flue gas, and has significant economic benefits. In the conventional process, the amount of regeneration flue gas is large, and the investment cost and operating cost of the subsequent denitration and desulfurization system are high. The present application uses oxygen-enriched regeneration to greatly reduce the amount of regeneration flue gas, thereby reducing the investment cost and operating cost of the subsequent denitration and desulfurization system, and having good economic benefits.

[0025] Third, the present application can greatly reduce the emission of pollutants, and achieve efficient capture of CO2. In a conventional process, the amount of catalytic cracking regeneration flue gas is large, and the CO2 therein cannot be collected and stored, and is directly discharged into the atmosphere. The amount of regeneration flue gas generated by the present application is greatly reduced, and the desulfurized and denitrified regeneration flue gas contains only CO2 and water vapor. After condensation and separation, CO2-rich gas with a concentration of more than 98% can be separated, and efficient capture of CO2 is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Figure 1 is a structural schematic diagram of an oxygen-enriched regeneration catalytic cracking system according to the present application;

[0027] In the figure, 1 is a preheating furnace, 2 is an oxygen permeable membrane reactor, 3 is a regenerator, 4 is a catalytic cracking reactor, 5 is a first heat exchanger, 6 is a second heat exchanger, and 7 is a condenser. DETAILED DESCRIPTION

[0028] As shown in Figure 1 Figure 1, an oxygen-enriched regeneration catalytic cracking system according to the present application includes a preheating furnace 1, an oxygen permeable membrane reactor 2, a regenerator 3, a catalytic cracking reactor 4, a first heat exchanger 5, a second heat exchanger 6, and a condenser 7. The oxygen permeable membrane reactor 2 has a plate-and-tube structure, the diameter of the oxygen permeable membrane tube is 15 mm, the thickness of the oxygen permeable membrane is 2 mm, and the tube spacing is 2 times the tube diameter. The oxygen permeable membrane is a perovskite-type mixed conductor oxygen permeable membrane, and the pressure difference across the oxygen permeable membrane tube is 1 MPa. The catalytic cracking process is as follows:

[0029] (1) Air at 20°C enters the second heat exchanger 6 and exchanges heat with 150-300°C exhaust flue gas to increase the temperature to 30-50°C, forming preheated air, which then enters the first heat exchanger 5 and exchanges heat with 600-750°C high-temperature oxygen-poor air, increasing the temperature to 400-600°C to form heated air, which is further heated to 450-650°C high-temperature air in the preheating furnace 1, and then enters the oxygen permeable membrane reactor 2. Oxygen in the high-temperature air permeates from the inside of the oxygen permeable membrane tube to the outside of the tube, and 600-750°C high-temperature oxygen-poor air in the tube exchanges heat with 30-50°C preheated air in the first heat exchanger 5, reducing the temperature to 40-60°C and becoming low-temperature oxygen-poor air, which is discharged.

[0030] (2) Oxygen entering the outside of the oxygen permeable membrane reactor 2 mixes and reacts with 650-800°C incomplete regeneration flue gas from the regenerator 3 to form 600-750°C oxygen-rich gas. After the oxygen-rich gas is introduced out of the oxygen permeable membrane reactor 2, 5-30% enters the preheating furnace 1, and the remaining oxygen-rich gas enters the regenerator 3 and reacts with spent catalyst from the catalytic cracking reactor 4 to perform incomplete reaction, generating 650-800°C incomplete regeneration flue gas containing CO.

[0031] (3) 5-30% of the incomplete regeneration flue gas generated by the regenerator 3 enters the preheating furnace 1 and reacts with the 600-750℃ oxygen-rich gas entering the preheating furnace 1. Another part of the incomplete regeneration flue gas enters the oxygen permeable membrane reactor 2 as circulating flue gas to dilute and carry away oxygen, and to promote the continuous migration of oxygen.

[0032] (4) The 650-800℃ incomplete regeneration flue gas in the preheating furnace 1 reacts completely with the 600-750℃ oxygen-rich gas and releases heat to heat the air, becoming 150-300℃ exhaust flue gas which enters the second heat exchanger 6 to exchange heat with 20℃ air. After the temperature is reduced, it enters the condenser separator 7 to separate CO2 with a concentration of more than 98% for collection and treatment.

[0033] (5) The regenerated catalyst enters the catalytic cracking reactor 4 and reacts with the raw oil entering the catalytic cracking reactor 4 to produce an oil-gas mixture which enters the subsequent fractionation, absorption, and stabilization system for treatment. The completed catalyst returns to the regenerator 3 for oxygen-rich regeneration treatment to complete the cycle of the catalyst.

Claims

1. An oxygen-enriched regenerative catalytic cracking system, characterized by: include: The second heat exchanger heats the normal temperature air to preheated air through the exhaust gas; a first heat exchanger, heating the preheated air to heated air by means of high-temperature oxygen-depleted air; The preheating furnace releases heat through a complete reaction between oxygen-rich gas and incompletely regenerated flue gas, heating the heated air to high-temperature air and generating exhaust flue gas; The oxygen permeable membrane reactor separates the high-temperature air into high-temperature oxygen-depleted air and oxygen. The oxygen is mixed with the incompletely regenerated flue gas and reacts to form oxygen-rich gas. Catalytic cracking reactor, which catalytically cracks the crude oil through a catalyst; The regenerator supplies oxygen-rich gas to react incompletely with the catalyst to be regenerated, generating incompletely regenerated flue gas containing CO and regenerated catalyst.

2. The oxygen-enriched regenerative catalytic cracking system according to claim 1, characterized in that: It also includes a condensation separator, which is used to separate the exhaust flue gas passing through the second heat exchanger into H2O and CO2.

3. The oxygen-enriched regenerative catalytic cracking system according to claim 1, characterized in that: The oxygen permeable membrane reactor is a plate-and-tube structure.

4. The oxygen-enriched regenerative catalytic cracking system according to claim 1, characterized in that: The oxygen permeable membrane reactor has a circular oxygen permeable membrane tube with a diameter of 1-30 mm, a thickness of 0.1-6 mm, and a tube spacing of 0.5-4 times the tube diameter.

5. The oxygen-enriched regenerative catalytic cracking system according to claim 4, characterized in that: The operating temperature of the oxygen permeable membrane reactor is 400-1100°C, the pressure difference on both sides of the oxygen permeable membrane tube is 0-10MPa, and the pressure inside the oxygen permeable membrane tube is not lower than the pressure outside the oxygen permeable membrane tube.

6. The oxygen-enriched regenerative catalytic cracking system according to claim 4, characterized in that: The oxygen permeable membrane of the oxygen permeable membrane tube is a perovskite, fluorite-perovskite, fluorite-metal or perovskite-metal structure.

7. The oxygen-enriched regenerative catalytic cracking system according to claim 4, characterized in that: The oxygen permeable membrane of the oxygen permeable membrane tube is a single-layer membrane or a multi-layer membrane.

8. An oxygen-enriched regenerative catalytic cracking process, characterized in that: Catalytic cracking of crude oil is carried out using any one of the oxygen-enriched regeneration catalytic cracking systems described in claims 1 to 7.

9. An oxygen-enriched regenerative catalytic cracking process according to claim 8, characterized in that: The temperature, pressure and flow rate of the high-temperature air entering the oxygen permeable membrane reactor are controlled to adjust the oxygen concentration in the oxygen-rich gas.

10. An oxygen-enriched regenerative catalytic cracking process according to claim 9, characterized in that: The volume concentration of oxygen in the oxygen-rich gas is adjusted to 0-80%.

11. The oxygen-enriched regenerative catalytic cracking process according to claim 9, characterized in that: The volume concentration of oxygen in the oxygen-rich gas is adjusted to 25-30%.

12. The oxygen-enriched regenerative catalytic cracking process according to claim 8, characterized in that: The oxygen-rich gas entering the regenerator accounts for 70-95% of the total oxygen-rich gas.

13. The oxygen-enriched regenerative catalytic cracking process according to claim 8, characterized in that: The incomplete regeneration flue gas entering the preheating furnace accounts for 5-30% of the total incomplete regeneration flue gas.

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