Microsphere catalyst spray drying tower based on bidirectional loop flow gas distribution device

Abstract

The application discloses a microsphere catalyst spray drying tower based on a bidirectional circular flow gas distribution device, which comprises a microsphere catalyst spray drying tower, a bidirectional circular flow gas distribution device arranged at the top of the microsphere catalyst spray drying tower, a ring-shaped gas distribution chamber, a center gas winding column arranged in the ring-shaped gas distribution chamber, the center gas winding column being fixed at the bottom of the ring-shaped gas distribution chamber and being sealed at the bottom, two symmetrical tangential gas inlet pipes of the center gas winding column, the two gas inlet pipes being communicated with the center gas winding column, and a gas distribution device connected to the bottom of the ring-shaped gas distribution chamber; and the ring-shaped gas distribution chamber is communicated with the microsphere catalyst spray drying tower through the gas distribution device. The application can adjust and control the gas distribution state, thereby avoiding the phenomena of particle adhesion and tower adhesion, improving the sphericity of products and optimizing the particle size distribution of catalysts.

Description

Technical Field

[0001] This invention belongs to the field of petroleum catalytic cracking technology and relates to a microsphere catalyst spray drying tower based on a two-way circulating gas distribution device. Background Technology

[0002] The catalytic cracking (FCC) process is a crucial production link in oil refining enterprises, playing a vital role in producing gasoline and diesel. The catalytic cracking reaction requires an FCC catalyst to accelerate the reaction; however, FCC catalysts age and deactivate after a certain number of cycles, resulting in significant consumption in continuous industrial production. Therefore, developing high-quality FCC catalysts has become a core technology for the refining industry to reduce costs, increase yield, and improve selectivity.

[0003] The main steps in FCC catalyst preparation include binder formation, gelation, colloid filtration, spray drying, and calcination. Spray drying, in particular, involves using different types of atomizers or atomization principles within a spray drying chamber to disperse the raw material slurry into fine droplets. These droplets then come into contact with a drying medium heated by an external heat source, achieving mass and heat transfer between the two materials to ultimately obtain a dried solid product. This is a typical process of synergistic mass and heat transfer. Currently, FCC spray drying equipment suffers from several problems. The similarity in flow state between the hot air and catalyst droplets in the spray tower leads to hot air flow deviation and catalyst backmixing. Furthermore, the similar open area ratios of the two-stage trays in the equipment affect the hot air distribution and the thermal energy utilization rate of the spray-calcination system, resulting in severe particle adhesion, tower sticking, and poor product sphericity and particle size distribution. These issues significantly impact the yield of FCC microsphere catalysts and increase preparation costs. Summary of the Invention

[0004] The purpose of this invention is to provide a microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device, which can adjust and control the gas distribution state to avoid particle adhesion and tower sticking, improve product sphericity and optimize catalyst particle size distribution.

[0005] The technical solution adopted in this invention is:

[0006] The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device includes a microsphere catalyst spray drying tower, a bidirectional circulating gas distribution device arranged at the top of the microsphere catalyst spray drying tower, and an annular gas distribution chamber. The top of the annular gas distribution chamber is sealed, and a central gas column is arranged inside the annular gas distribution chamber. The central gas column is fixed to the bottom of the annular gas distribution chamber and sealed at the bottom. Two symmetrical tangential gas inlet pipes are arranged on the central gas column, and both gas inlet pipes are connected to the central gas column. A gas distribution device is connected to the bottom of the annular gas distribution chamber. The annular gas distribution chamber is connected to the microsphere catalyst spray drying tower through the gas distribution device.

[0007] The invention is further characterized by:

[0008] The annular gas distribution chamber is cylindrical, frustum-shaped, or conical.

[0009] The annular gas distribution chamber is a frustum, and the projected area of ​​the upper part of the frustum is 1 / 3 of the projected area of ​​the lower part; the diameter of the lower part of the annular gas distribution chamber is the same as the diameter of the microsphere catalyst spray drying tower body.

[0010] The annular gas distribution chamber and the gas distribution device are connected by a perforated plate. The gas distribution device is a two-stage gas distributor or a tubular distributor with an opening ratio of 0.5% to 50%.

[0011] Furthermore, the annular gas distribution chamber and the gas distribution device are connected by a perforated plate. The gas distribution device consists of two secondary gas distributors with an opening rate of 15%, and the distance between two adjacent secondary distributors is 1 / 5 of their diameter.

[0012] The central gas is arranged around a cylindrical or rectangular tube.

[0013] Furthermore, the central gas surrounding the column is a circular tube, and the cross-sectional area of ​​the central gas surrounding the column is 1 / 10 to 9 / 10 of the projected cross-section of the annular gas distribution chamber.

[0014] The microsphere catalyst spray drying tower has a cylindrical body, a catalyst outlet at the bottom, and an extended colloid input mechanism inside the tower body.

[0015] Furthermore, the number of centrally symmetrical colloid input mechanisms is set to four.

[0016] Furthermore, the bottom of the microsphere catalyst spray drying tower is a cone, the catalyst outlet is located at the bottom of the cone, and a gas outlet is provided on the side wall of the cone.

[0017] The beneficial effects of this invention are:

[0018] High-temperature gas enters the central gas column through two tangential gas inlet pipes, forming a swirling flow with tangential velocity. This flow gradually rises and enters the gas pre-distribution chamber through the opening at the top of the central gas column. The upward-flowing swirling flow is deflected by the top wall of the pre-distribution chamber, forming a reverse swirling flow. This flow then passes through the perforated plate at the bottom of the pre-distribution chamber, exits the bidirectional circulating gas distribution device, and enters the microsphere catalyst spray drying tower. The FCC catalyst slurry enters the microsphere catalyst spray drying tower from the slurry nozzle of the colloid input mechanism to complete the spray drying process, yielding the FCC catalyst. Gas-solid separation is achieved under the influence of gravity. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device according to the present invention;

[0020] Figure 2 for Figure 1 Top view;

[0021] Figure 3 This is a structural diagram of the bidirectional circulating gas distribution device in this invention.

[0022] In the attached diagram: 1. Inlet pipe; 2. Annular gas distribution chamber; 3. Central gas circulation column; 4. Gas distribution device; 5. Colloidal input mechanism; 6. Microsphere catalyst spray drying tower; 7. Gas outlet; 8. Catalyst outlet. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention relates to a microsphere catalyst spray drying tower based on a two-way circulating gas distribution device, such as... Figures 1-3 The system includes a microsphere catalyst spray drying tower 6, with a bidirectional circulating gas distribution device arranged at the top of the microsphere catalyst spray drying tower 6. The bidirectional circulating gas distribution device includes an annular gas distribution chamber 2, which is sealed at the top. A central gas circulation column 3 is arranged inside the annular gas distribution chamber 2, which is fixed to the bottom of the annular gas distribution chamber 2 and sealed at the bottom. Two symmetrical tangential air inlet pipes 1 are arranged on the central gas circulation column 3, and both air inlet pipes 1 are connected to the central gas circulation column 3. A gas distribution device 4 is connected to the bottom of the annular gas distribution chamber 2. The annular gas distribution chamber 2 is connected to the microsphere catalyst spray drying tower 6 through the gas distribution device 4.

[0025] The annular gas distribution chamber 2 is cylindrical, frustum, or conical. When the annular gas distribution chamber 2 is frustum, the projected area of ​​the upper end is 1 / 3 of the projected area of ​​the lower end. The diameter of the lower end of the annular gas distribution chamber 2 is consistent with the diameter of the cylinder of the microsphere catalyst spray drying tower 6.

[0026] The annular gas distribution chamber 2 is connected to the gas distribution device 4 via a perforated plate. The gas distribution device 4 is a two-stage gas distributor or a tubular distributor with an opening ratio of 0.5% to 50%. When the gas distribution device 4 is a two-stage gas distributor, it is preferable to use two two-stage gas distributors with an opening ratio of 15%, and the distance between two adjacent two-stage distributors is 1 / 5 of its diameter.

[0027] The central gas circulation column 3 can be a circular tube or a rectangular tube, preferably a circular tube. The cross-sectional area of ​​the central gas circulation column 3 is 1 / 10 to 9 / 10 of the projected cross-section of the annular gas distribution chamber 2; preferably 1 / 3.

[0028] The air intake pipe 1 can be a round pipe or a rectangular pipe, preferably a round pipe.

[0029] The microsphere catalyst spray drying tower 6 has a cylindrical body with a conical bottom and a cone angle of 15 to 50 degrees, preferably 30 degrees. A catalyst outlet 8, which is circular or rectangular, is located at the bottom of the cone. A gas outlet 7 is located on the side wall of the cone. An extended colloid input mechanism 5 is installed inside the microsphere catalyst spray drying tower 6, with a slurry spray nozzle at its outlet end. The distance between the colloid input mechanism 5 and the bottom of the microsphere catalyst spray drying tower 6 is 1 / 50 to 2 of the cylinder diameter, preferably 1 / 5 of the cylinder diameter. Preferably, four centrally symmetrical colloid input mechanisms 5 are provided.

[0030] The method and principle of using the microsphere catalyst spray drying tower based on the bidirectional circulating gas distribution device of this invention are as follows:

[0031] High-temperature gas enters symmetrically into the central gas circulation column 3 through a tangential inlet pipe. The high-temperature gas temperature is set to 450–650℃; the inlet linear velocity is 5–25 m / s; and the relative humidity is 0.1–25%. The preferred temperature is 500℃; the inlet linear velocity is 20 m / s; and the relative humidity is 5%.

[0032] High-temperature gas forms a swirling flow within the central gas column 3. The swirling flow enters the annular gas distribution chamber 2 from bottom to top through the upper opening. After being deflected by the top wall of the annular gas distribution chamber 2, it passes through the gas distribution device 4 and comes into contact with the FCC catalyst slurry from the colloidal input mechanism 5. The spray drying process is completed inside the microsphere catalyst spray drying tower 6. The gas and catalyst particles are discharged from the gas and catalyst particle outlets at the bottom cone of the microsphere catalyst spray drying tower, respectively.

[0033] In the microsphere catalyst spray drying tower, to ensure uniform gas distribution, the pressure drop of the high-temperature gas passing through the bidirectional circulating gas distribution device is 1 / 20 to 1 / 2 of the pressure drop at the inlet and outlet of the spray tower.

[0034] Preferably, the pressure drop of the high-temperature gas through the bidirectional circulating gas distribution device is 1 / 5 of the pressure drop at the inlet and outlet of the spray tower.

[0035] This invention ensures a uniform and reasonable distribution of temperature and hot air within the spray drying tower. It effectively prevents problems such as uneven hot air distribution and hot air deviation within the drying tower, avoids back-mixing of wet catalyst particles, particle adhesion, and tower sticking, thereby effectively controlling product sphericity, particle adhesion, and particle size distribution, and improving the fluidization state and reaction performance of the FCC catalyst.

Claims

1. A microsphere catalyst spray drying tower based on a two-way circulating gas distribution device, characterized in that, The system includes a microsphere catalyst spray drying tower (6), the top of which is equipped with a bidirectional circulating gas distribution device. The bidirectional circulating gas distribution device includes an annular gas distribution chamber (2), the top of which is sealed. A central gas column (3) is provided inside the annular gas distribution chamber (2), which is fixed to the bottom of the annular gas distribution chamber (2) and sealed at the bottom. The central gas column (3) is provided with two symmetrically tangential air inlet pipes (1), both of which are connected to the central gas column (3). The annular gas distribution chamber (2) is connected to a gas distribution device (4) at its bottom; the annular gas distribution chamber (2) is connected to the microsphere catalyst spray drying tower (6) through the gas distribution device; the microsphere catalyst spray drying tower (6) has a cylindrical body, a catalyst outlet (8) is provided at the bottom of the microsphere catalyst spray drying tower (6), and an extended colloid input mechanism (5) is provided inside the cylinder of the microsphere catalyst spray drying tower (6); the bottom of the microsphere catalyst spray drying tower (6) is a cone, the catalyst outlet (8) is located at the bottom of the cone, and a gas outlet (7) is provided on the side wall of the cone.

2. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The annular gas distribution chamber (2) is cylindrical, frustum-shaped, or conical.

3. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The annular gas distribution chamber (2) is a frustum, and the projected area of ​​the upper end of the frustum is 1 / 3 of the projected area of ​​the lower end; the diameter of the lower end of the annular gas distribution chamber (2) is the same as the diameter of the cylinder of the microsphere catalyst spray drying tower (6).

4. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The annular gas distribution chamber (2) is connected to the gas distribution device (4) through a perforated plate. The gas distribution device (4) is a two-stage gas distributor or a tubular distributor with an opening ratio of 0.5% to 50%.

5. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The annular gas distribution chamber (2) is connected to the gas distribution device (4) through a perforated plate. The gas distribution device (4) consists of two secondary gas distributors with an opening rate of 15%. The distance between two adjacent secondary distributors is 1 / 5 of their diameter.

6. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The central gas surrounds the column (3) as a circular or rectangular tube.

7. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The central gas surrounding the column (3) is a circular tube, and the cross-sectional area of ​​the central gas surrounding the column (3) is 1 / 10 to 9 / 10 of the projected cross-section of the annular gas distribution chamber (2).

8. The microsphere catalyst spray drying tower based on a bidirectional circulating gas distribution device as described in claim 1, characterized in that, The number of colloid input mechanisms (5) is four, arranged in a centrally symmetrical manner.

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