KR890003434B1 - Apparatus for transferring particles from one zone to another - Google Patents

Abstract

The catalyst regenerator comprises an upper zone wherein catalyst particles are subject to regeneration by a gas stream flowing radially therethrough, and a lower zone wherein the particles are subject to a gas stream flowing upwardly. There being gravity flow of particles from the upper zone to the lower zone, sampling of the catalyst particles to determine their level of regeneration is performed in an annular transistor zone located between the upper zone and the lower zone. The transition zone isolates the upwardly- flowing gas stream from contacting the catalyst particles in the upper zone.

Description

Particulate transport device

1 is a partial cross-sectional elevation view of a preferred catalyst regeneration or regeneration mechanism in which the lower catalyst moves continuously between the annular upper band, the annular transition band capable of sampling the lower catalyst, and the substantially cylindrical lower band.

FIG. 2 is a partially enlarged cross-sectional view of the instrument of FIG. 1 illustrating the transition band and its contacts to the upper and lower bands thereof. FIG.

3 is a sectional view taken along line 3-3 of FIG.

* Explanation of symbols for main parts of the drawings

10: vertical pressure tower 18: porous inner screen cylinder

20: catalyst inlet conduit 28: upper "burn-out" band (annular processing band)

30: column 44 of catalyst fine particles used: transition zone

66: lower processing band 72: central capture band

80, 90: wedge wire 92, 94: rod

The present invention relates to a particulate transporting device which uses gas to process or react with particulates of a contacting substance such as a catalyst, and the particulates pass by gravity flow from one reaction zone to another. Examples of the processes performed in such devices include various catalytic hydrocarbon conversion techniques such as reforming, hydrotreating, dehydrogenation and dehydrogenation dimerization as well as regeneration of coke-contaminated catalyst. A specific example of a catalyst regeneration device in which a catalyst covered with coke during the catalytic reforming operation in the catalyst regeneration device moves through the carbon combustion removal portion and passes through the halogenation portion downwards to the dry portion is described in Greenwood et al. 3,652, 231, the subject matter of which is incorporated herein by reference.

In this particular arrangement, the catalyst moves downward into the annular space between a pair of regularly spaced concentric porous screens and is subject to a first recirculating flue gas of a radial flow, preferentially comprising a relatively low content of oxygen, and secondly air It is subject to a second gas of radial flow containing halogen and steam.

The first and second gases are introduced into the annular elongated prenium space surrounding the annular screen and separated in the prenium by an annular baffle dividing the prenium into two regions. Apparently with this arrangement, some of the recycle gas diffuses downward into the dependent catalyst zone of the second gas, while some of the second gas diffuses upward into the catalyst zone dependent on the first gas. .

The diffusion makes it possible to collect the catalyst in the annular space and it is difficult to determine the specific sampling location in the space where it can be said that the sample is representative of the catalyst after it has been burned off to the desired extent. In practice, despite the presence of sampling devices as disclosed in US Pat. Nos. 3, 786, 682 and 3, 973, 440, halogenation and drying and It is common to operate only the burnout band of the regenerator without operating the same low band.

In addition, after the regenerator has been operated for a sufficient number of hours such that the catalyst passes through the inoperative halogenation and drying zone and is introduced into the bottom of the tower, a predetermined sample is taken with the catalyst exiting the tower. Since this method consumes a lot of time, it is sometimes only performed at the start of operation.

It is an object of the present invention to provide an apparatus for gravity transporting a column of particulate contact material from the upper treatment zone as long as the particulates come into contact with the first gas to another lower treatment zone where it comes into contact with the second gas. After complete treatment in the upper band, transfer is carried out in such a way that a region is formed to collect representative material.

Another object of the present invention is to provide a conveying apparatus for assisting the gravity movement of particulate contact material between the upper treatment zone and the lower treatment zone.

Another object of the present invention is to provide a conveying device which allows the particulate contact material to freely move from the upper gas treatment zone to the lower band while preventing the gas in the lower band from moving upward into the upper zone. .

The stated and other objects and advantages are achieved by the above device of the present invention. In a preferred embodiment, particulate contact materials, such as spherical particulates of the catalyst, can be transported from one treatment zone to another by means of the normal excitation method. In certain applications in which the apparatus of the present invention includes the burnout and chlorination zones of a catalyst regenerator, the catalyst particulates are transferred to the apparatus from a reactor that is at least partially covered with coke during the reaction with hydrocarbons. The microparticles can be transferred to the upper treatment zone of the instantaneous device by means of an uplifting device, or other suitable transfer means, which is not an accessory of the present invention. Similarly, the particular apparatus used to transfer the particulates from the lower treatment zone of the circulator to another and / or behind the reactor is not an accessory to the present invention.

The first or upper treatment zone of the instantaneous device includes a pair of vertically stretched and radially spaced porous members, such as a screen made by spirally winding and welding a wedge-shaped wire around a plurality of support rods. As disclosed in U.S. Patent Nos. 3, 652, 231, it is preferred that the screen is cut and re-rotated at an angle of 90 ° relative to its original position so that the wire is parallel to the vertical flow path of the catalyst particulates. The setting minimizes the friction of the catalyst particulate bed moving downward into the annular space between the members, and the pressure of the radially flowing process gas can increase particulates, increase back pressure and cause incomplete distribution of the gases. It also reduces the possibility of fastening to the vertical flow slot formed by the wires present. The device accommodates an annular plenium space or area around a pair of spaced screens described above into which a first processing gas, such as a recycled flue gas, with a controlled amount of air is introduced. The air portion of the screen will be adjusted so that the recycle flue gas will have a relatively low oxygen content of 0.8%. By relatively lengthening the settling time of the catalyst particulates by the gas and constantly recirculating a large amount of gas through the screen and the catalyst particles, coke on the particulates is gradually burned out to reduce the carbon weight on the particulates. Will decrease from 5% to about 0.2%. The treatment gas is introduced into the central gas collection zone located radially inward of the screen together with the combustion products.

Because of the high oxygen content, the carbon is burned off quickly and the temperature of the catalyst bed is increased. Therefore, the oxygen content in the upper zone must be kept very low. It has been noted that elevated temperatures cause breakdown or at least reduce the expected life of the catalyst particulates. However, as disclosed below, if oxygen is not supplied sufficiently in the upper zone, coke remains on the particulates, heating and destroying the particulates when they are in contact with the high content of oxygen in the lower zones, thereby providing oxygen in the upper zones. Sufficient supply should provide sufficient coke removal.

Moreover, the device includes a lower cylindrical band. The catalyst particles contained in the lower cylinder zone are moved downwardly by gravity through the cylinder zone when material is recovered from the bottom of the cylinder zone. The transition band, which will be described later, connects the upper and lower bands and evenly distributes the catalyst from the upper band to the lower band. In the radially upper band, the first gas, i.e. a large amount of recycled flue gas in which a small amount of oxygen is applied in the form of air, must be continuously recycled by the blower to gradually burn off the coke surface on the catalyst. However, in the lower cylindrical zone substantially no gas flow rate is needed since the catalyst particulates can only be maintained by being sucked into the second gas. Preferably, the second gas is air richer in oxygen than the first gas and to which a chlorinating agent such as Cl ₂ , HCl or organic chloride is added. The second gas gradually flows upward through the lower bed and flows into the central gas collecting zone. The gas trapping zone has a bottom portion formed by an upper surface of the catalyst fine particles in the lower zone, a lower end portion of the side thereof formed by a radially inner surface of the inner wall of the transition zone, and an inner porous wall of the annular upper zone. Upper ends of the sides are formed. At least when the catalyst contains platinum, the platinum particles are uniformly redistributed over the useful surface area of the support to maintain the catalyst particulates during the period of intake into the second gas. This operation is preferable because the platinum component of the catalyst tends to be unevenly distributed when coke on the catalyst fine particles is burned off in the upper zone.

The transition zone described above comprises a pair of inner and outer non-porous wall members that extend vertically and form a substantially annular flow tunnel, and wherein the catalyst particulates exiting the annular upper band have a substantially cylindrical annular outer edge through the tunnel. It can be introduced almost uniformly.

In a preferred embodiment, the brick of the transition zone is spaced at a more regular interval in the government than at the bottom so that the brick extends downwards the cylindrical screen that forms the upper zone. The inner wall of the transition zone preferably has a straight length in order to smoothly flow the fine particles. It is also possible to extend the outer wall straight down to provide a transition zone of constant cross section. However, it is preferable that the outer wall taper the middle region between its upper and lower ends almost inward. Thus, the transition band has an annular section of considerably less area at its bottom than at its government. As the radial width of the transition zone gradually decreases, the amount of contained catalyst particles can be significantly reduced compared to having a zone of the same height and parallel walls extending downward from the screen cylinder. More importantly, the reduced cross section reduces the gas flow compared to the same height transition band with the same parallel plane. The tapered wall also provides a good mounting structure for sampling.

The vertical scale of the transition band is at least equal to the distance between the screen cylinders, and should preferably be larger. This dimensioning ensures that the pressure drop between the upper and lower bands is more than the radial pressure drop across the upper band. Maintaining the above-described scale, a major portion of the first gas is introduced radially into the central capture zone through the upper band screen. In addition, the riser gas in the lower band passes vertically into the central capture zone, which, of course, is a pressure lower than the pressure of the first and second gases when the first and second gases enter the relevant zone. . The second gas does not enter the transition zone because of the significant back pressure of the catalyst bed in the transition zone as well as the small downward flow of the first gas. Rather, due to the absence of back pressure, the second gas is easily introduced into the central collection zone. There is no back pressure because the catalyst fine particles in the lower zone form the bottom of the collection zone.

The height of the transition zone is chosen so as to obtain a pressure drop through the catalyst particles in the transition zone such that the magnitude of the pressure drop is sufficient to fluidize the catalyst particles at the junction of the transition zone and the lower band and is provided through the transition zone. The height of the transition band must be high enough so that one gas cannot flow downward. When fluidization occurs, friction of the particles occurs rapidly. Conversely, the transition band height should be short enough so that at least a small amount of the first gas continues to flow downwards. Downflow of the first gas assists gravity flow of catalyst particles through the transition zone. In the device, the transition height at least equal to the distance between the screens in the first band is worse but necessary than the result obtained by the transition height such as at least three times the distance between the screens.

According to the foregoing, the catalyst fine particles in the transition zone represent the extent to which coke is burned off very uniformly. Therefore, if the catalyst fine particles in the transition zone can be sampled, the fine particles can accurately know the processing level achieved in the combustion elimination zone. By performing the sampling continuously or at least periodically, it is possible to better control the regeneration process so as to minimize the damage of the catalyst fine particles due to overheating as much as possible. For example, when the coke is not sufficiently burned off as a result of sampling, the oxygen content of the first gas may be increased. Similarly, the oxygen content of the burnout gas can be reduced if the burnout is completed sufficiently. The ability to accurately determine the burn-off rate indicates that catalyst particulates entering the high-oxygen lower zone with a significant amount of coke remaining on the surface can react with oxygen as quickly as possible, allowing the catalyst particulates to be heated immediately to temperatures above 2000F. This is especially important when considering. This high temperature melts and destroys the microparticles, while somewhat lower, but still elevated temperatures greatly shorten the service life of the microparticles. The oxygen level in the first gas is sufficient so that the coarse catalyst particles are removed from the upper combustion elimination zone so that coke is sufficiently removed so as not to damage the fine particles due to the temperature increase when the oxygen rich lower zone is reached. Ideally. This reduction in oxygen levels in the upper zone also ensures that the catalyst particulates are treated at the minimum temperature in the upper zone.

Therefore, the service life of the catalyst fine particles can be maximized. First, it is necessary to provide the upper band with at least slightly more oxygen than the absolute required amount to establish the desired coke burnout. However, excessive oxygen increases the catalyst temperature and thereby shortens the catalyst life. Since temperature is very important for the life of the catalyst, it is particularly important to reduce the catalyst temperature even at least in the upper zone, in which the catalyst lasts longer than one hour. In the apparatus of the present invention, a small amount of coke will remain in the center of the particulate because the low oxygen content gas in the upper zone cannot burn off all coke of the catalyst particulate. This residue has a total carbon content of about 0.2% when leaving the upper zone and is burned off quickly when the particulates enter the lower zone first and come into contact with the high oxygen content gas therein. It is natural that the catalyst particulates are heated by such combustion, but assuming that they reduce the coke to a desired level, the temperature by the combustion does not rise higher than the temperature at the top of the upper burnout zone. , Soon falls to the level of the remainder of the lower band. In addition, since very little coke is present and it takes considerable time for oxygen to diffuse into the center of the particulates in which the remaining coke is set up, a very short period of temperature increase is of no practical importance.

Referring to FIG. 1, a preferred embodiment of the apparatus of the present invention comprises a two stage regenerator portion and a vertical pressure column, collectively referred to as 10. The removable head portion 12 is connected to the cylindrical outer wall 14 of the tower by fastening means (not shown). The non-porous end ring member 16 is welded to the upper end head portion 12 and to the upper end of the lower end porous inner screen cylinder 18. A plurality of catalyst inlet conduits 20 are provided which are adapted to receive the spent catalyst from the reactor or other sources, which are passing through the head portion 12. In addition, the gas outlet assembly 22 is installed in the head portion 12 to remove the gas from the inside of the tower (10). The radially extending screen support flange 24 is provided between the head portion 12 and the flanges 12 'and 14' with respect to the wall 14, and has an upper end mounting ring portion 27 which runs downward. The branches serve to mount the outer screen cylinder 26 perforated. The annular space between the inner and outer porous screen portions 18, 26 forms an upper gas treatment zone 28 comprising a column 30 of spent catalyst fine particles 32 on which coke is deposited. Typically, coke is about 5% by weight of catalyst particulates. The zone 28 is also referred to as a "carbon burn off" zone because the zone 28 is through the gas vapor inlet means 34 and the annular distribution portion 36 between the wall 14 and the screen 26. This is because coke is almost removed or burned off when the microparticles 32 are continuously contacted by the first treatment gas stream. The first gas is preferably a recycle flue gas, such as the gas exiting through the outlet 22, and a sufficient amount of air is applied to the gas to have a relatively low oxygen content of about 0.8%. The low oxygen content keeps the carbon removal rate low, thereby adjusting the maximum temperature at which the catalyst particulates are processed and thereby preventing the particulates from overheating. As described above, the ability to allow accurate sampling with the device is to adjust the oxygen level of the first gas to minimize temperature and increase catalyst life.

Immediately below the upper “burn out” zone 28 is a transition zone 44, an inner non-porous cylindrical end ring member 50 and an outer porous screen welded to the lower end of the inner porous screen cylinder 18. The upper end of the transition zone is formed by a similar end ring member welded to the cylinder 26. The lower end of the transition zone 44 is partitioned by a cylindrical inner wall portion 54 of the transition element welded to the ring member 50 on the inner face of the transition zone 44. Alternatively, the ring 50 can be made longer to eliminate the element 54.

와 같지만, 그의 저부에 있어서는 폭

가

의 50% 이하인 것이 바람직하다. 또한, 전이대역(44)은 평행한 측벽과 일정한 폭의 환상단면을 가질수 있다 할찌라도 상기 전이대역의 소정높이

를 테이퍼식으로 설계함으로써 일정폭 t5 의 대역과 비교할때 상기 전이대역을 하방으로 통과할 수 있는 제1기체의 양을 감소시키게 된다. 이러한 흐름감소는 촉매 미립자들이 제한된 개구를 통과해야만 할때 촉매베드중의 미립자(32)에 의해서 발생된 배압을 증가시킴으로서 야기된다. 또한, 전이대역(44)의 단면을 테이퍼지게 함으로써 미립자들이 상기 전이대역을 하방으로 통과할때 칼럼(30)중의 미립자들의 속도를 증가시킬수 있다. 상기 미립자들의 하방이동을 제2도에서 유선으로 지시한 바와같이, 상부 기체 처리부분(36)중의 일부기체의 하방유동에 의해 보조한다.As is evident in FIG. 2, the transition zone appears to have a tapered cross section almost downward because its outer wall is formed by conical portions 56 and vertical portions 58 at an angle. Therefore, in the transition band transition, the width of the transition band is the width of the radial space between the screens 18 and 26.

Like, but at the bottom of it, the width

end

Is preferably 50% or less. In addition, the transition zone 44 may have a parallel sidewall and an annular cross section of a constant width, although the predetermined height of the transition zone is sufficient.

The tapered design reduces the amount of first gas that can pass downward through the transition band when compared to a band of constant width t5. This decrease in flow is caused by increasing the back pressure generated by the particulates 32 in the catalyst bed when the catalyst particulates must pass through the restricted openings. In addition, by tapering the cross section of the transition zone 44, it is possible to increase the speed of the particulates in the column 30 as they pass downward through the transition zone. The downward movement of the particulates is assisted by the downward flow of some of the gas in the upper gas treatment portion 36, as indicated by the streamline in FIG.

It is evident that the particulates 32 ′, which have moved all the way down through the upper treatment zone 28 and have flowed into the transition zone 44, can know the degree of burnout performed in the zone 28. The reason for this condition is that a relatively oxygen-rich gas enters the gas inlet 62 and is distributed upwards through the lower cylinder treatment zone 66 by a distribution means such as a flow distributor 68 to provide the particulate 32 '. Because there is no possibility of coming into contact with. The gas flowing upwardly through the lower zone 66 flows directly into the central capture zone 72 and mixes therein with the gas flowing radially inwardly through the upper treatment zone 28 and through the gas outlet 22. Exit the device. The pressure in the central capture zone 72 is lower than the pressure of the gas entering the inlets 34 and 62. The top face 66 'of the lower treatment zone 66 is formed by catalyst particles 32' flowing around the lower edge 54 'of the inner wall 54 of the transition element by gravity, so that the gas flowing upwards It does not flow into the transition band 44. The flow cannot occur because particulate 32 ′ in the transition zone 44 creates back pressure against the gas. In addition, the pressure of a small amount of downstream gas in the transition zone is also higher than the pressure in the central capture zone (72).

The flow rate of column 30 through zone 28 and zone 66 is determined by the rate at which particulate 32 "exits zone 66 through outlet 74. Said particulate exiting zone 66 They may be subjected to additional treatments as needed, such as drying, which does not form part of the present invention.

In order to sample the fine particles 32 'in the transition zone 44, a sampling device designated by the generic name 76 can be used. Although the particular type of sampling device used does not form part of the present invention, the sample container 78 is provided with a val section 80 and connected to an outlet 84 with a flow control valve 86 by a flange end 82. ).

FIG. 3 is an enlarged cross-sectional view of line 3-3 of FIG. 2 and merely discloses the form of the annular treatment band 28, which is a wedge wire welded to the rods 92 and 94 to form the screens 18 and 26. FIG. Each of the 88 and 90 has a scale slot 96 smaller than the diameter of the catalyst fine particles so that gas passes through it but the catalyst fine particles do not. The above application of the present invention to catalyst regenerators merely illustrates the application of the present invention and is not intended to limit the scope of the invention as defined by the following claims.

Claims (7)

Particles that move the contact material downward from the upper annular zone 28 where the particulates come into contact with the first gas stream radially flowing through the zone, and from the lower zone 66 where the particles come into contact with the second gas stream. In the conveying apparatus, the upper annular zone 28 is formed by axially extending portions 18, 26 of a pair of coaxial screen elements spaced in the radial direction; The axially extending portion is configured to receive a plurality of gas flow openings of a size that permits gas flow but does not allow passage of contact particulates; The lower zone 66 is substantially cylindrical and has a vertically elongated non-porous outer wall portion that radially receives contacting particulates in the lower zone 66; The outer wall portion is connected to the radially outer element 26 of the pair of screen elements by an outer wall of a substantially annular transition element 50, 52, 54, 56, 58; The substantially annular transition element comprises an outer wall portion 58 of the lower band 66 and an outer wall portion 52 connected to the outer screen element 26 and a radially inner portion of the pair of screen elements 18, 26. A cylindrical non-porous inner portion (50, 54) connected to the element (18), and the bottom end of the inner wall portion (50, 54) is the upper height limit that contact particulates can reach within the lower zone (66). To form; The lower cylindrical zone 66 is coaxially associated with the cylindrical gas trapping zone formed by the device at at least one position whose sidewall at its bottom is adjacent to the upper annular zone 28 and located above the zone 28. Are in direct and open communication; Means (62, 68) are provided for introducing a second gas stream into the lower portion of the apparatus at a specific pressure so as to flow upward through the lower cylindrical zone (66); Each of the first and second gas streams first flows through the bed of contact particulates 32 in each of its bands 28 and 66 and flows into the collection band 72; The gas collecting zone is maintained at a pressure lower than the specific pressure of the first and second gas streams so that the second gas stream flows directly into the gas collecting zone 72 from the government of the lower cylindrical zone 66. And; The inner wall portions 50 and 54 of the annular transition element are the vertical heights of the transition zone 44 containing the particulates between the upper band 28 and the lower band 66.

Forming a; Vertical height of the transition band 44

Is the radial distance between the screen elements 18, 26.

Particle transfer apparatus characterized in that it generates a back pressure to sufficiently accommodate the fine particles of the above contact material to prevent the second gas from flowing into the transition zone (44). The distance between the screen elements (18, 26) of the transition band (50, 54) according to claim 1,

Particle conveying device having a vertical height of at least three times. 2. The vertical height of claim 1 sufficient to limit the amount of downward flow of the first gas stream through the transition zone at a rate at which the transition zones 50, 54 containing the particulates do not sufficiently fluidize the particulates in the device.

Particle conveying apparatus having a. The particulate transporting apparatus of claim 1, wherein the contact material comprises porous catalyst particulates. 2. The sample collection port (84) of claim 1, wherein a sampling port (84) is attached to the transition element (56) at an intermediate position between the upper band (28) and the lower band (66), and the sampling port (84) is provided with the sampling port (84). And a particulate transport device allowing sampling of the contact material particulates in the transition zone. The particulate transport apparatus of claim 1, wherein the transition elements (50, 52, 54, 56, 58) are shaped closer to each other at their bottom than at the government. 7. The particulate transport according to claim 6, wherein the bottom walls of the transition elements (50, 52, 54, 56, 58) are spaced at intervals of 50% or less of the radial distance between the screen elements (18, 26) in a radial direction. Device.

Images