Strippers, processes for catalytic cracking spent catalyst stripping, catalytic cracking units

Abstract

The present application relates to the technical field of petroleum chemical industry, and particularly to a stripper and application thereof, a method for stripping of spent catalyst of catalytic cracking, and a catalytic cracking device. The stripper comprises a stripper cylinder, a particle inlet, a particle outlet, two gas feed pipes, a gas outlet, and a double-loop pipe distributor. The double-loop pipe distributor is arranged inside the stripper cylinder and annularly around the central axis of the stripper cylinder. When the double-loop pipe distributor injects stripping steam, the structure of the double-loop pipe distributor is adjusted so that the stripping steam injected through the double-loop pipe distributor forms a demarcation line in the stripper cylinder, which divides the interior of the stripper cylinder into a central region and an annular region. The stripper provided by the present application has high stripping efficiency and improves the operation stability of the stripper under high particle circulation flow rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of petroleum chemical technology, in particular to a stripper and application thereof, a method for stripping spent catalyst of catalytic cracking, and a catalytic cracking device. BACKGROUND

[0002] At present, most of the catalytic cracking strippers at home and abroad are bubbling fluidized beds provided with internal components. The carbonized catalyst particles flow from top to bottom, and the stripping steam flows from bottom to top to realize countercurrent contact. The operating gas velocity of the domestic FCC device stripper is between 0.15-0.3 m / s, and the operating gas velocity of the foreign device can reach 0.4-0.5 m / s. Compared with the fluidized bed in the conventional laboratory research, the macroscopic particle circulation flow rate of the stripper is higher. Based on the cross section of the stripper cylinder, the particle circulation flow rate of the domestic device stripper is generally between 30-70 kg / (m 2 ·s), and the highest reported abroad is 90-120 kg / (m 2 ·s).

[0003] In addition to the internal components, the gas distributor with more uniform gas distribution is another effective way to improve the gas-solid contact and increase the stripping efficiency. Considering the need for high mass flow rate of the catalyst particles flowing downward, only two types of gas distributors, i.e. the loop gas distributor and the dendritic distributor, can be applied in the catalyst stripper. At present, most of the gas distributors used in the device strippers are a loop gas distributor. However, the loop gas distributor has the disadvantages of single structure, uneven gas distribution, and large dead zone. For the stripper with a larger diameter, the stripping steam can only be distributed in the annular area close to the loop gas distributor, and the central area often forms a local dead zone due to low stripping rate, thereby reducing the gas-solid contact effect in the area.

[0004] The dendritic distributor is another type of gas distributor commonly used in industrial fluidized bed reactors. This type of distributor has been widely used in FCC regenerators, and has better gas distribution uniformity than the loop gas distributor. However, the dendritic distributor has a complex structure, and the minimum flow area ratio at the installation position is often smaller than that of the loop gas distributor, and is usually only about half of the cross-sectional area of the stripper. Due to the high particle circulation flow rate in the stripper, the "liquid flooding" phenomenon similar to that in the gas-liquid packed tower is likely to occur during the operation fluctuation of the device. This phenomenon is also called "solid flooding" in the fluidization research. "Solid flooding" is caused by the local particle downward velocity being greater than the bubble upward velocity in the fluidized bed. The occurrence of "solid flooding" hinders the downward flow of the catalyst particles, affects the gas-solid two-phase contact effect, and further causes the decrease of the stripping efficiency and the instability of the device operation, and even may cause the local or overall loss of fluidization of the catalyst (i.e. the "bridging" phenomenon of the catalyst), which causes the interruption of the overall catalyst circulation and the forced unscheduled shutdown of the device. SUMMARY

[0005] The present application aims to overcome the low stripping efficiency of the existing catalytic cracking stripper due to uneven distribution of stripping steam, and the impact of high flow rate of particle circulation on stable operation, and provides a new stripper and its application, a method for stripping of catalytic cracking spent catalyst, and a catalytic cracking device containing the stripper, which has better uniformity of stripping steam distribution, so that the stripper has high stripping efficiency and ensures stable operation. At the same time, the catalytic cracking device containing the stripper improves the yield of oil and gas products and reduces the regeneration load and energy consumption of the device.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a stripper, which comprises: a stripper cylinder, wherein a particle inlet, a particle outlet, two gas feed pipes, a gas outlet and a double-loop distributor are arranged on the stripper cylinder; and the double-loop distributor is arranged inside the stripper cylinder and annularly around the central axis of the stripper cylinder.

[0007] When the double-loop distributor injects stripping steam, the structure of the double-loop distributor is adjusted so that the stripping steam injected through the double-loop distributor forms a demarcation line in the stripper cylinder, which divides the interior of the stripper cylinder into a central region and an annular region.

[0008] Preferably, the double-loop distributor is selected from small-loop distributors and large-loop distributors with different heights, and the small-loop distributors and the large-loop distributors are respectively provided with first nozzles and second nozzles for downward injection.

[0009] Preferably, the vertical distance between the small-loop distributors and the large-loop distributors is ≥0.3m, preferably 0.3-0.8m.

[0010] Preferably, the ratio of the central diameter of the small-loop distributor to the diameter of the central region is 0.4-0.8:1; and the ratio of the average value of the inner diameter of the stripper cylinder and the diameter of the central region to the central diameter of the large-loop distributor is 1:0.9-1.1.

[0011] Preferably, the ratio of the cross-sectional area S of the central region to the cross-sectional area S' of the annular region is 1:1-3.

[0012] The second aspect of the present application provides the use of the stripper provided in the first aspect in stripping of catalytic cracking spent catalyst.

[0013] The third aspect of the present application provides a method for stripping of catalytic cracking spent catalyst, which is carried out in the stripper provided in the first aspect, and the method comprises: contacting and stripping the catalytic cracking spent catalyst entering the stripper through the particle inlet with the stripping steam sprayed through the double-loop distributor in the stripper cylinder to obtain the stripped spent catalyst and the gaseous product.

[0014] Preferably, the apparent gas velocity of the stripping steam is ≥0.1 m / s; and the particle circulation flow rate of the catalytic cracking spent catalyst is ≥10 kg / (m 2 ·s).

[0015] The fourth aspect of the present application provides a catalytic cracking device, which comprises: a reactor, a stripper provided in the first aspect and a regenerator connected in sequence;

[0016] The reactor is used for contacting and reacting the oil product and the catalyst to obtain the oil gas product and the spent catalyst; the stripper is used for contacting and stripping the spent catalyst and the stripping steam to obtain the stripped spent catalyst and the gaseous product; and the regenerator is used for regenerating the stripped spent catalyst to obtain the regenerated catalyst.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] (1) The stripper provided in the present application overcomes the problem that the traditional stripper cannot simultaneously have uniform stripping steam distribution and stable operation by arranging the double-loop distributor in the interior of the stripper cylinder; and the stripping efficiency of the stripper can be further improved and the operation stability of the stripper under high particle circulation flow rate can be improved by optimizing the structure of the double-loop distributor.

[0019] (2) The stripper provided in the present application is used for stripping of catalytic cracking spent catalyst, and the residual oil gas in the catalytic cracking spent catalyst is effectively removed by realizing efficient contact between the stripping steam and the catalytic cracking spent catalyst; and the stripper is used in the catalytic cracking device, which strengthens the stripping efficiency, thereby improving the light oil yield of the device and reducing the regeneration load and energy consumption of the device. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic view of a stripper provided in the present application, wherein the arrow indicates the spraying direction of the stripping steam, and the dashed line indicates the central axis of the stripper cylinder;

[0021] Figure 2(a) is a schematic view of the central zone and the annular zone of a stripper provided in the present application;

[0022] Figure 2(b) is a top view of a double-loop distributor in a stripper provided in the present application;

[0023] Figure 3 is a structural diagram of a first nozzle provided on a single ring pipe distributor according to the present application;

[0024] Figure 4 is a structural diagram of another stripper according to the present application; wherein the arrow indicates the injection direction of stripping steam, and the dotted line indicates the central axis of the stripper cylinder;

[0025] Figure 5 is a structural diagram of another stripper according to the present application; wherein the arrow indicates the injection direction of stripping steam, and the dotted line indicates the central axis of the stripper cylinder;

[0026] Fig. 6(a) is a top view of a single ring pipe distributor;

[0027] Fig. 6(b) is a top view of a dendritic distributor;

[0028] Fig. 6(c) is a top view of a double ring pipe distributor according to the present application.

[0029] Explanation of Reference Signs

[0030] DETAILED DESCRIPTION

[0031] The endpoints of the ranges and any values disclosed herein are not to be understood as limited to the exact values recited as the exact dimensions are not to be construed as being critical. It is intended to convey that a range of values will be encompassed as long as the exact values are within the scope of the disclosed values. The disclosed numerical ranges are therefore to be understood flexibly to include both the precise values recited and a range of values that the exact values are deemed to be encompassed. Each individual value suggested by this disclosure is included and can be combined in any combination with each of the illustrated values.

[0032] In the present application, unless otherwise specified, the "first" and "second" do not represent the order of precedence, nor do they limit the respective steps or materials, but are only used to distinguish the same materials or steps. For example, "first nozzle" and "second nozzle" are only used to represent the same step.

[0033] In the present application, unless otherwise specified, the top of the container refers to the position of 0-10% from top to bottom of the container; the upper part of the container refers to the position of 10-40% from top to bottom of the container; the middle part of the container refers to the position of 40-60% from top to bottom of the container; the lower part of the container refers to the position of 60-90% from top to bottom of the container; and the bottom of the container refers to the position of 90-100% from top to bottom of the container.

[0034] The first aspect of the present application provides a structural diagram of a stripper as shown in Figure 1 -2, which is provided by Figure 1-2 indicates that the stripper I includes: a stripper cylinder 1, on which a particle inlet 2, a particle outlet 3, two gas feed pipes 4 and a gas outlet 5 are provided, as well as a double-ring pipe distributor; wherein, the double-ring pipe distributor is disposed inside the stripper cylinder 1 and is arranged in a ring around the central axis of the stripper cylinder 1.

[0035] When stripping steam is injected into the dual-ring pipe distributor, the structure of the dual-ring pipe distributor is adjusted so that the stripping steam injected through the dual-ring pipe distributor forms a dividing line 14 inside the stripper cylinder 1, which is used to divide the interior of the stripper cylinder 1 into a central area and an annular area.

[0036] In this invention, unless otherwise specified, the dividing line does not actually exist. Instead, it is used as the boundary formed by the stripping steam injected through the double-ring pipe distributor by adjusting the structural settings of the double-ring pipe distributor.

[0037] According to the present invention, such as Figure 1 As shown, preferably, the dual-ring pipe distributor is selected from a small ring pipe distributor 6 and a large ring pipe distributor 7 with different heights, and the small ring pipe distributor 6 and the large ring pipe distributor 7 are respectively provided with a first nozzle and a second nozzle for downward spraying.

[0038] In this invention, unless otherwise specified, the dual-ring pipe distributor is selected from small-ring pipe distributors and large-ring pipe distributors with different heights. The dual-ring pipe distributor can be divided into a small-ring pipe distributor set at the top and a large-ring pipe distributor set at the bottom, or it can be divided into a large-ring pipe distributor set at the top and a small-ring pipe distributor set at the bottom.

[0039] In this invention, unless otherwise specified, the center diameter of the small ring pipe distributor is less than the center diameter of the large ring pipe distributor, and the outer diameter of the small ring pipe distributor is less than the inner diameter of the large ring pipe distributor; wherein, the center diameter of the small ring pipe distributor is the average of the inner and outer diameters of the small ring pipe distributor; similarly, the center diameter of the large ring pipe distributor is the average of the inner and outer diameters of the large ring pipe distributor.

[0040] In the present application, in order to avoid the gas jet of the upper annular distributor from washing the lower annular distributor, the lower annular distributor should not belong to the jet influence zone of the upper annular distributor. Preferably, the vertical distance between the small annular distributor and the large annular distributor is ≥ 0.3 m, preferably 0.3-0.8 m, for example, 0.3 m, 0.4 m, 0.5 m, 0.6 m, 0.7 m, 0.8 m, and any value in the range between any two numerical values. In the present application, the specific value of the vertical distance depends on the size of the nozzle of the upper annular distributor and the size of the jet velocity, when the size of the nozzle and the size of the jet velocity are small, the vertical distance is small, and vice versa.

[0041] In some embodiments of the present application, preferably, the central diameter of the small annular distributor < the diameter of the central zone < the central diameter of the large annular distributor < the inner diameter of the stripper cylinder.

[0042] In some embodiments of the present application, preferably, the ratio of the central diameter of the small annular distributor and the diameter of the central zone is 0.4-0.8:1, for example, 0.4:1, 0.5:1, 0.6:1, 0.65:1, 0.7:1, 0.8:1, and any value in the range between any two numerical values, preferably 0.6-0.7:1. The purpose is to inject the stripper steam from the first nozzle on the small annular distributor into the central zone as evenly as possible, so as to achieve uniform contact between the stripper steam and the catalyst particles in this area.

[0043] In some embodiments of the present application, preferably, the ratio of the average of the inner diameter of the stripper cylinder and the diameter of the central zone to the central diameter of the large annular distributor is 1:0.9-1.1, for example, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1, and any value in the range between any two numerical values, preferably 1:0.95-1.05. Again, the purpose is to inject the stripper steam from the second nozzle on the large annular distributor into the annular zone as evenly as possible, again in order to achieve uniform contact between the stripper steam and the particles in this area.

[0044] In some embodiments of the present application, preferably, the ratio of the cross-sectional area S of the central zone to the cross-sectional area S' of the annular zone is 1:1-3, for example, 1:1, 1:2, 1:3, and any value in the range between any two numerical values.

[0045] In the present application, the stripping steam flow rate into the double-loop distributor is proportional to the cross-sectional area of the central zone / annular zone. Preferably, the stripping steam flow rate Q into the small loop distributor and the cross-sectional area S of the central zone satisfy: Q=a×S, wherein a>0; the stripping steam flow rate Q' into the large loop distributor and the cross-sectional area S' of the annular zone satisfy: Q'=a'×S', wherein a'>0.

[0046] In some embodiments of the present application, preferably, the stripping steam flow rate Q into the small loop distributor and the cross-sectional area S of the central zone satisfy: Q=a×S, wherein a is selected from 0.1-0.5; the stripping steam flow rate Q' into the large loop distributor and the cross-sectional area S' of the annular zone satisfy: Q'=a'×S', wherein a' is selected from 0.1-0.5.

[0047] In some embodiments of the present application, preferably, the stripping steam flow rate Q into the small loop distributor, the stripping steam flow rate Q' into the large loop distributor, the cross-sectional area S of the central zone and the cross-sectional area S' of the annular zone satisfy: .

[0048] In the present application, the stripping steam flow rate into the double-loop distributor is proportional to the number of the first nozzle / second nozzle. Preferably, the stripping steam flow rate Q into the small loop distributor and the number N of the first nozzle satisfy: Q=b×N, wherein b>0; the stripping steam flow rate Q' into the large loop distributor and the number N' of the second nozzle satisfy: Q'=b'×N', wherein b'>0.

[0049] In the present application, without special circumstances, along the height of the stripper cylinder, the small loop distributor can be arranged above or below; similarly, the large loop distributor can be arranged above or below.

[0050] In some embodiments of the present application, preferably, as shown in Figure 1 and Figure 5 When the small loop distributor 6 is arranged above the large loop distributor 7, the small loop distributor 6 is provided with the first nozzles inclined inwardly, and the large loop distributor 7 is provided with the second nozzles inclined inwardly and outwardly. In this way, under the premise of ensuring high stripping efficiency, the erosion and wear of the large loop distributor arranged below are avoided.

[0051] In one specific embodiment of the present invention, when the small ring pipe distributor is disposed above the large ring pipe distributor, the small ring pipe distributor is provided with a first nozzle that sprays downward and is inclined inward, and the large ring pipe distributor is provided with a second nozzle that sprays downward and is inclined inward, and a second nozzle that sprays downward and is inclined outward; wherein, the second nozzles inclined inward and the second nozzles inclined outward are arranged alternately.

[0052] In other embodiments of the invention, preferably, such as Figure 4 As shown, when the large annular pipe distributor 7 is positioned above the small annular pipe distributor 6, the large annular pipe distributor 7 is equipped with a second nozzle tilted outwards, and the small annular pipe distributor 6 is equipped with a first nozzle tilted inwards and outwards. This configuration, while ensuring high stripping efficiency, avoids erosion and wear on the lower small annular pipe distributor.

[0053] In one specific embodiment of the present invention, when the large ring pipe distributor is disposed above the small ring pipe distributor, the large ring pipe distributor is provided with a ring of downward spraying and inclined inward second nozzles, and the small ring pipe distributor is provided with a ring of downward spraying and inclined inward first nozzles, and a ring of downward spraying and inclined outward first nozzles; wherein, the inclined inward first nozzles and the inclined outward first nozzles are alternately arranged.

[0054] In this invention, unless otherwise specified, "inward tilt" means that the extension line of the nozzle axis points to the central axis of the stripper cylinder; "outward tilt" means that the extension line of the nozzle axis points to the inner wall of the stripper cylinder.

[0055] In some embodiments of the present invention, preferably, the tilt angle α of the first nozzle is 20-50°, and the tilt angle α' of the second nozzle is 20-50°. Here, the tilt angle refers to the angle between the nozzle axis and the vertical line.

[0056] In some embodiments of the present invention, preferably, the first nozzle and the second nozzle penetrate the small ring tube distributor and the large ring tube distributor, respectively.

[0057] In this invention, to ensure the uniformity of gas distribution, preferably, the first nozzle and the second nozzle are each independently a dual-diameter nozzle; more preferably, along the flow direction of the stripping steam, the first nozzle and the second nozzle each independently include: a small-diameter section, an optional expanded-diameter section, and a large-diameter section.

[0058] In this invention, to ensure uniform gas distribution and suppress particle wear, the stripping steam velocity through the small-diameter section is 30-70 m / s, and the stripping steam velocity through the large-diameter section is 10-30 m / s.

[0059] In some embodiments of the present application, preferably, the inner diameter ratio of the small diameter section and the large diameter section is 1:1.3-2.5, for example, 1:1.3, 1:1.5, 1:1.8, 1:2, 1:2.5, and any value in the range between any two of the values; the length ratio of the small diameter section and the large diameter section is 1:2-10, for example, 1:2, 1:4, 1:5, 1:6, 1:8, 1:10, and any value in the range between any two of the values.

[0060] In some embodiments of the present application, preferably, the taper angle of the diameter expansion section is >90°, preferably 120-180°, for example, 120°, 150°. Wherein, the taper angle of the diameter expansion section refers to the included angle between the diameter expansion section and the large diameter section.

[0061] A structure diagram of a first nozzle provided on a small ring pipe distributor according to the present application is shown in Figure 3 As can be seen from Figure 3 , the first nozzle 9 penetrates the small ring pipe distributor 6, and the first nozzle 9 is a double-diameter nozzle; along the flow direction of the stripping steam, the first nozzle 9 comprises a small diameter section 10, a diameter expansion section 11, and a large diameter section 12.

[0062] In some embodiments of the present application, preferably, as shown in Figure 1 , the particle inlet 2 and the gas outlet 5 are respectively arranged at the top of the stripper cylinder 1; the particle outlet 3 is arranged at the bottom of the stripper cylinder 1.

[0063] In some embodiments of the present application, preferably, as shown in Figure 1 , the gas feed pipe 4 is arranged on the side wall of the stripper cylinder 1, and the gas feed pipe 4 is connected to the double ring pipe distributor. That is, the gas feed pipe 4 is respectively connected to the small ring pipe distributor 6 and the large ring pipe distributor 7.

[0064] In some embodiments of the present application, preferably, as shown in Figure 1 , the stripper further comprises an inner member 8 arranged in the stripper cylinder 1, and the inner member 8 is arranged above the double ring pipe distributor.

[0065] In some embodiments of the present application, preferably, the shortest distance between the inner member and the ring pipe distributor arranged thereon is 0-0.5m, for example, 0m, 0.1m, 0.2m, 0.3m, 0.5m, and any value in the range between any two of the values.

[0066] In some embodiments of the present application, preferably, the height of the inner member is 0.1-0.8m, for example, 0.1m, 0.2m, 0.3m, 0.4m, 0.6m, 0.8m, and any value in the range between any two of the values, preferably 0.1-0.4m.

[0067] In the present application, the inner member can further improve the stripping efficiency. Preferably, the inner member comprises, but is not limited to Figure 1 and Figure 4 the disc ring baffle inner member shown in Fig. 1, Figure 5 the packing stripping inner member shown in Fig. 2. In the present application, compared with the disc ring baffle inner member, the packing stripping inner member has more mass transfer units with smaller size, and it is more difficult for the gas-solid two-phase to transfer in the lateral direction, thus it is more necessary to have uniformly distributed stripping steam to ensure that the stripper has a better initial gas-solid contact quality.

[0068] The second aspect of the present application provides an application of the stripper provided in the first aspect in stripping of catalytic cracking spent catalyst.

[0069] In the present application, unless otherwise specified, the catalytic cracking spent catalyst refers to catalytic cracking spent catalyst.

[0070] The third aspect of the present application provides a method for stripping of catalytic cracking spent catalyst, which is carried out in the stripper provided in the first aspect, and the method comprises: contacting and stripping the catalytic cracking spent catalyst entering the stripper through the particle inlet of the stripper with the stripping steam sprayed through the double-loop distributor in the stripper cylinder to obtain the stripped spent catalyst and gaseous products.

[0071] In the present application, unless otherwise specified, the catalytic cracking spent catalyst contains part of the residual oil and gas products in addition to the coke.

[0072] In some embodiments of the present application, preferably, the superficial gas velocity of the stripping steam is ≥0.1m / s; the particle circulation flow rate of the catalytic cracking spent catalyst is ≥10kg / (m 2 ·s); further preferably, the superficial gas velocity of the stripping steam is 0.1-0.5m / s; the particle circulation flow rate of the catalytic cracking spent catalyst is 10-120kg / (m 2 ·s).

[0073] In the present application, unless otherwise specified, the superficial gas velocity parameter refers to the ratio of the total volume flow of the stripping steam under working conditions to the cross-sectional area of the stripper; the particle circulation flow rate parameter refers to the mass of the particles (for example, catalytic cracking spent catalyst) flowing through the unit cross-sectional area of the stripper per unit time.

[0074] The fourth aspect of the present application provides a catalytic cracking device, which comprises a reactor, a stripper provided by the first aspect and a regenerator connected in sequence.

[0075] The reactor is used for contacting and reacting oil products and catalysts to obtain oil gas products and spent catalysts; the stripper is used for contacting and stripping the spent catalysts and stripping steam to obtain stripped spent catalysts and gas products; and the regenerator is used for regenerating the stripped spent catalysts to obtain regenerated catalysts.

[0076] According to a particularly preferred embodiment of the present application, a stripper comprises a stripper cylinder provided with a particle inlet, a particle outlet, two gas feed pipes, a gas outlet and a double-loop distributor; wherein the double-loop distributor is arranged inside the stripper cylinder and annularly around the central axis of the stripper cylinder.

[0077] When the double-loop distributor injects stripping steam, the structure of the double-loop distributor is adjusted so that the stripping steam injected through the double-loop distributor forms a demarcation line in the stripper cylinder, which is used to divide the interior of the stripper cylinder into a central region and an annular region.

[0078] The double-loop distributor is selected from small-loop distributors and large-loop distributors with different heights, and the small-loop distributors and the large-loop distributors are respectively provided with first nozzles and second nozzles that spray downward.

[0079] The vertical distance between the small-loop distributors and the large-loop distributors is 0.3-0.8 m.

[0080] The ratio of the central diameter of the small-loop distributor to the diameter of the central region is 0.4-0.8:1; and the ratio of the average value of the inner diameter of the stripper cylinder and the diameter of the central region to the central diameter of the large-loop distributor is 1:0.9-1.1.

[0081] Preferably, the ratio of the cross-sectional area S of the central region to the cross-sectional area S' of the annular region is 1:1-3.

[0082] The present application will be described in detail below through examples.

[0083] Example 1

[0084] The present application provides a structural diagram of a stripper as shown in Figure 1 The present application provides a structural diagram of a stripper as shown in Figure 1It can be seen that the stripper I comprises: a stripper cylinder 1, a particle inlet 2 and a gas outlet 5 arranged at the top of the stripper cylinder 1, two gas feeding pipes arranged on the sidewall of the stripper cylinder 1, a particle outlet 3 arranged at the bottom of the stripper cylinder 1, and a disc ring-shaped inner component 8, a small ring pipe distributor 6 and a large ring pipe distributor 7 arranged in the interior of the stripper cylinder 1 from top to bottom in sequence;

[0085] wherein the vertical distance between the small ring pipe distributor 6 and the large ring pipe distributor 7 is 0.3-0.8 m;

[0086] wherein the ratio of the central diameter of the small ring pipe distributor 6 to the diameter of the central area is 0.4-0.8:1; the ratio of the average value of the inner diameter of the stripper cylinder 1 and the diameter of the central area to the central diameter of the large ring pipe distributor 7 is 1:0.9-1.1;

[0087] wherein a circle of first nozzles 9 downwardly spraying and obliquely inwardly arranged is uniformly arranged on the circumference of the small ring pipe distributor 6, a circle of second nozzles 13 downwardly spraying and obliquely inwardly arranged and a circle of second nozzles 13 downwardly spraying and obliquely outwardly arranged are uniformly arranged on the circumference of the large ring pipe distributor 7, and the second nozzles obliquely inwardly and obliquely outwardly are arranged in an interlaced manner;

[0088] wherein the oblique angle of the first nozzles is 20-50°, and the oblique angle of the second nozzles is 20-50°;

[0089] wherein the first nozzles and the second nozzles are each independently a double-diameter nozzle; along the flow direction of the stripping steam, the first nozzles and the second nozzles each comprise: a small-diameter section, an expanding-diameter section and a large-diameter section, wherein the ratio of the inner diameters of the small-diameter section and the large-diameter section is 1:1.3-2.5, and the ratio of the lengths of the small-diameter section and the large-diameter section is 1:2-10; the taper angle of the expanding-diameter section is 120-180°;

[0090] wherein the ratio of the cross-sectional area S of the central area to the cross-sectional area S' of the annular area is 1:3; the ratio of the stripping steam flow rate Q passing through the small ring pipe distributor to the stripping steam flow rate Q' passing through the large ring pipe distributor is 1:3; the gas velocity of the stripping steam passing through the small-diameter section of the first nozzles and the second nozzles is 35-60 m / s, and the gas velocity of the stripping steam passing through the large-diameter section of the first nozzles and the second nozzles is 13-22 m / s.

[0091] Example 2

[0092] The present application provides another structure diagram of a stripper as shown in Figure 4 which is different from example 1 in that the large ring pipe distributor 7 is arranged upwardly and the small ring pipe distributor 6 is arranged downwardly;

[0093] The periphery of the small ring pipe distributor 6 is uniformly provided with a circle of downwardly spraying and obliquely inwardly first nozzles and a circle of downwardly spraying and obliquely outwardly first nozzles, wherein the obliquely inwardly first nozzles and the obliquely outwardly first nozzles are alternately arranged.

[0094] The cross-sectional area ratio of the central zone to the annular zone is 1:1, and the stripping steam flow ratio of the small ring pipe distributor to the large ring pipe distributor is 1:1.

[0095] Example 3

[0096] Another structure of the stripper is shown in FIG. 6 (b), wherein the disc ring inner member 8 is replaced by a 6-layer packing stripping inner member 8. Figure 5

[0097] The shortest distance between the inner member 8 and the small ring pipe distributor 6 arranged thereon is 0 mm.

[0098] Example 1

[0099] A structure of the stripper is shown in FIG. 4 (b), wherein the disc ring inner member 8 is replaced by a 6-layer packing stripping inner member 8. Figure 1 Figure 1 As shown in FIG. 4 (b), the stripper I includes a stripper cylinder 1, a particle inlet 2 and a gas outlet 5 arranged at the top of the stripper cylinder 1, two gas feeding pipes arranged on the sidewall of the stripper cylinder 1, a particle outlet 3 arranged at the bottom of the stripper cylinder 1, and a disc ring inner member 8, a small ring pipe distributor 6 and a large ring pipe distributor 7 arranged in the interior of the stripper cylinder 1 from top to bottom.

[0100] The vertical distance between the small ring pipe distributor 6 and the large ring pipe distributor 7 is 0.39 m; the central diameter of the small ring pipe distributor 6 is 10 cm; the central diameter of the large ring pipe distributor 7 is 30 cm; the inner diameter of the stripper cylinder 1 is 40 cm; and the diameter of the central zone is 16 cm.

[0101] As shown in FIG. 6 (c), the periphery of the small ring pipe distributor 6 is uniformly provided with a circle of downwardly spraying and obliquely inwardly 10 first nozzles 9, and the periphery of the large ring pipe distributor 7 is uniformly provided with a circle of downwardly spraying and obliquely inwardly 15 second nozzles 13 (see the o mark in the figure) and a circle of downwardly spraying and obliquely outwardly 15 second nozzles 13 (see the ⊕ mark in the figure), and the obliquely inwardly second nozzles and the obliquely outwardly second nozzles are alternately arranged.

[0102] The oblique angle α of the first nozzles is 45 o , the inner diameter ratio of the small diameter section to the large diameter section of the first nozzles is 1:1.5, and the included angle β between the diameter expansion section and the large diameter section is 150​​o the inclination angle of the second nozzle is 45 o the inner diameter ratio of the small diameter section and the large diameter section of the second nozzle is 1:1.7, and the included angle β of the expansion section and the large diameter section is 150 o

[0103] The shortest distance between the inner member and the small ring pipe distributor is 0.1 m.

[0104] The cross-sectional area S of the central zone and the cross-sectional area S' of the annular zone are in a ratio of 1:3; the stripping steam flow rate Q passing through the small ring pipe distributor and the stripping steam flow rate Q' passing through the large ring pipe distributor are in a ratio of 1:3; the gas velocity of the stripping steam passing through the small diameter section of the first nozzle and the second nozzle is 35-60 m / s, and the gas velocity of the stripping steam passing through the large diameter section of the first nozzle and the second nozzle is 13-22 m / s.

[0105] Comparative Example 1

[0106] According to the stripper of Example 1, except that the inner part of the stripper I is provided with a single ring pipe distributor, a top view of which is shown in FIG. 6(a).

[0107] The single ring pipe distributor has a central diameter of 28 cm and is provided with 24 downwardly spraying and outwardly inclined nozzles, the inclination angle of the nozzles being 45°. The nozzles are double-diameter nozzles, and the inner diameter ratio of the small diameter section and the large diameter section of the nozzles is 1:1.7, and the included angle β of the expansion section and the large diameter section is 150°.

[0108] Comparative Example 2

[0109] According to the stripper of Example 1, except that the inner part of the stripper I is provided with a tree-shaped distributor, a top view of which is shown in FIG. 6(b).

[0110] The tree-shaped distributor is provided with 45 vertical downward openings.

[0111] Test Example

[0112] The stripping efficiency and operating performance of the strippers provided in Example 1 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

[0113] Table 1

[0114]

[0115] As can be seen from the data in Table 1, when the particle circulation flow rate is 31 kg / (m 2 ​• s), the stripper with the dendritic distributor of Comparative Example 2 had the highest stripping efficiency, which was related to its best air distribution uniformity, especially compared with the single ring distributor of Comparative Example 1, the improvement of stripping efficiency was 14-19% on average. The stripper with the double ring distributor of Example 1 had slightly lower stripping efficiency performance than Comparative Example 2, but the difference was not big.

[0116] When the particle circulation flow rate increased to 40-50 kg / (m 2 • s), the stripper with the dendritic distributor of Comparative Example 2 had the highest stripping efficiency, which was related to its best air distribution uniformity, especially compared with the single ring distributor of Comparative Example 1, the improvement of stripping efficiency was 14-19% on average. The stripper with the double ring distributor of Example 1 had slightly lower stripping efficiency performance than Comparative Example 2, but the difference was not big. 2 • s), the stripper with the dendritic distributor of Comparative Example 2 had the highest stripping efficiency, which was related to its best air distribution uniformity, especially compared with the single ring distributor of Comparative Example 1, the improvement of stripping efficiency was 14-19% on average. The stripper with the double ring distributor of Example 1 had slightly lower stripping efficiency performance than Comparative Example 2, but the difference was not big.

[0117] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A stripping device, characterized in that, The stripper includes: a stripper cylinder, on which a particle inlet, a particle outlet, two gas feed pipes and a gas outlet are provided, as well as a double-ring pipe distributor; wherein, the double-ring pipe distributor is disposed inside the stripper cylinder and arranged in a ring around the central axis of the stripper cylinder; the particle inlet is disposed at the top of the stripper cylinder; The dual-ring pipe distributor is selected from small-ring pipe distributors and large-ring pipe distributors with different heights, and the small-ring pipe distributor and the large-ring pipe distributor are respectively provided with a first nozzle and a second nozzle for downward spraying; the vertical distance between the small-ring pipe distributor and the large-ring pipe distributor is 0.3-0.8m; When stripping steam is injected into the double-ring pipe distributor, the structure of the double-ring pipe distributor is adjusted so that the stripping steam injected through the double-ring pipe distributor forms a dividing line in the stripper cylinder, which is used to divide the interior of the stripper cylinder into a central area and an annular area, and the ratio of the cross-sectional area S of the central area to the cross-sectional area S' of the annular area is 1:1-3. The ratio of the center diameter of the small ring pipe distributor to the diameter of the central area is 0.4-0.8:1; the ratio of the average value of the inner diameter of the stripper cylinder and the diameter of the central area to the center diameter of the large ring pipe distributor is 1:0.9-1.

1. Wherein, when the small ring pipe distributor is positioned above the large ring pipe distributor, the small ring pipe distributor is provided with a first nozzle inclined inward, and the large ring pipe distributor is provided with a second nozzle inclined inward and inclined outward; or, when the large ring pipe distributor is positioned above the small ring pipe distributor, the large ring pipe distributor is provided with a second nozzle inclined outward, and the small ring pipe distributor is provided with a first nozzle inclined inward and inclined outward.

2. The stripper according to claim 1, wherein, The center diameter of the small ring pipe distributor is less than the diameter of the central area, which is less than the center diameter of the large ring pipe distributor and less than the inner diameter of the stripper cylinder. And / or, the ratio of the center diameter of the small ring pipe distributor to the diameter of the central area is 0.6-0.7:1; the ratio of the average value of the inner diameter of the stripper cylinder and the diameter of the central area to the center diameter of the large ring pipe distributor is 1:0.95-1.

05.

3. The stripper according to claim 1, wherein, The stripping steam flow rate Q introduced into the small ring pipe distributor and the cross-sectional area S of the central region satisfy: Q = a × S, where a > 0; the stripping steam flow rate Q' introduced into the large ring pipe distributor and the cross-sectional area S' of the annular region satisfy: Q' = a' × S', where a' > 0; And / or, the stripping steam flow rate Q introduced into the small ring pipe distributor, the stripping steam flow rate Q' introduced into the large ring pipe distributor, the cross-sectional area S of the central region, and the cross-sectional area S' of the annular region satisfy: ; And / or, the stripping steam flow rate Q introduced into the small ring pipe distributor satisfies the following relationship with the number of first nozzles N: Q = b × N, where b > 0; the stripping steam flow rate Q' introduced into the large ring pipe distributor satisfies the following relationship with the number of second nozzles N': Q' = b' × N', where b' > 0.

4. The stripper according to claim 3, wherein, a is 0.1-0.5; a' is 0.1-0.

5.

5. The stripper according to claim 1, wherein, The tilt angle α of the first nozzle is 20-50°, and the tilt angle α' of the second nozzle is 20-50°.

6. The stripper according to claim 1, wherein, The first nozzle and the second nozzle respectively penetrate the small ring tube distributor and the large ring tube distributor; The first nozzle and the second nozzle are each independently a dual-diameter nozzle.

7. The stripper according to claim 6, wherein, Along the flow direction of the stripping steam, the first nozzle and the second nozzle each independently include: a small-diameter section, an expanded-diameter section, and a large-diameter section; The ratio of the inner diameter of the smaller diameter section to the larger diameter section is 1:1.3-2.5, and the ratio of their lengths is 1:2-10. Wherein, the cone angle of the expanded diameter section is >90°.

8. The stripper according to claim 7, wherein, The cone angle of the expanded diameter section is 120-180°.

9. The stripper according to claim 1, wherein, The gas outlet is located at the top of the stripper cylinder; the particle outlet is located at the bottom of the stripper cylinder. And / or, the gas feed pipe is disposed on the side wall of the stripper cylinder, and the gas feed pipe is connected to the double-ring pipe distributor.

10. The stripper according to any one of claims 1-9, wherein, The stripper also includes an internal component disposed within the stripper cylinder, and the internal component is disposed above the double-ring pipe distributor.

11. The stripper according to claim 10, wherein, The shortest distance between the internal component and the ring pipe distributor installed on it is 0-0.5m; And / or, the internal components are selected from disc annular baffle internal components and packing stripping internal components.

12. The stripper according to claim 11, wherein, The shortest distance between the internal component and the ring pipe distributor installed on it is 0-0.3m.

13. The application of the stripper according to any one of claims 1-12 in the stripping of catalytic cracking precursors.

14. A method for stripping a catalytic cracking precursor, the method being carried out in a stripper according to any one of claims 1-12, the method comprising: The catalytic cracking precursor entering through the particle inlet of the stripper is contacted with stripping steam injected through the dual-ring pipe distributor inside the stripper cylinder and stripped to obtain stripped precursor and gaseous products.

15. The method according to claim 14, wherein, The apparent gas velocity of the stripping steam is ≥0.1 m / s; the particle circulation rate of the catalytic cracking feedstock is ≥10 kg / (m³). 2 ·s); And / or, the apparent gas velocity of the stripping steam is 0.1-0.5 m / s; the particle circulation flow rate of the catalytic cracking precursor is 10-120 kg / (m³). 2 ·s).

16. A catalytic cracking unit, characterized in that, The catalytic cracking unit comprises: a reactor, a stripper as described in any one of claims 1-12, and a regenerator connected in sequence; The reactor is used to contact and react the oil and catalyst to obtain oil and gas products and a regenerating agent; the stripper is used to contact the regenerating agent and stripping steam to obtain stripped regenerating agent and gaseous products; the regenerator is used to regenerate the stripped regenerating agent to obtain a regenerating agent.

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