FI59117C - ADJUSTMENT OF ORGANIZATION OF REFORMING CATALYST - Google Patents

Description

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Patent · och regltterstyrelaan '' Antökan utitgd och utl.ikriftun pubi ic.nd 27 · 02.8l (32) (33) (31) Requested attenuation - B «gird prlorltet (71) Universal Oil Products Company, 30 Algonquin Road, Des Plaines ,

Illinois 600l6, USA (72) Arthur Raymond Greenwood, Niles, Illinois, Kenneth Donald Vesely,

This invention relates to a method and apparatus for regenerating carbonated catalyst moieties used in a single catalyst system. for multi-stage resuscitation of the subdivided particles introduced, in which the particles are contacted with vaporous and gaseous resuscitation currents as they move in a descending column under controlled gravity flow conditions.

Most hydrocarbon treatment processes performed in the presence of a catalyst usually have equipment for intermittent regeneration of the catalyst particles. However, in catalytic reforming cracking of an oil or other hydrocarbon feed stream, and in particular with a platinum-containing catalyst, most process units have operated on a fixed catalyst bed for long periods of time without catalyst regeneration.

When regeneration appeared necessary, the reactors were shut down and the catalyst was completely removed from each chamber and replaced with a new catalyst or a catalyst regenerated in the distant zone. Alternatively, certain 2,591 1 7 plants have had so-called "swing reactors", i.e. an additional reactor as well as carefully designed piping systems so that the mattress at a time could be separated as well as revived in situ. Complete catalyst replacement, like the exchange reactor process, is not a satisfactory system for maintaining the desired catalyst activities and vigorous reactions in multi-reactor bed reforming units, and it has therefore been found advantageous to provide a reforming system and a resuscitation system with the best moving bed. to provide a continuously operating overall equipment. It is also topical to keep the reforming unit in continuous operation to provide a continuous source of hydrogen for use in various hydrogen consuming process units in the treatment plant area.

It is thus a primary object of the invention to provide an improved regeneration system in which the downward gravity flow of catalyst particles through a series of regeneration steps is utilized.

Another object of the invention is to provide an apparatus arrangement in which the catalyst particles are brought into contact with a transverse regeneration current with the particles in a descending annular pillar.

It is also an object of the invention to provide an improved resuscitation chamber unit having a plurality of contact zones and means for enabling thermal expansion of the interior of the chamber.

The term "resuscitation" as used herein means more than one contact step or zone, as well as multi-step processing. In other words, the overall treatment involves more than just burning coal.

The main features of the invention appear from the appended claim 1.

3,591 1 7

As mentioned above, it is also an object of the invention to provide a unit system, or more particularly an elongate chamber, which allows the descending column of catalyst particles to move intermittently through different stages or zones of the chamber so that the particles can be intermittently contacted with desired resuscitation currents. That is, the sinking column is contacted with a controlled oxygen carbon removal stream in the first zone, a halogen vapor stream in the second and predominantly lower zone or stage, and then a hot air stream in the third stage to effect drying. The catalyst particles run as a continuous column, although the flow can be stopped and started from time to time and the flow rate can be adjusted the same in each contact zone, although contact times can vary along the cross-sectional area or length of the elongate chamber in each zone of the elongate chamber.

The present improved equipment system is particularly suitable for regenerating small spherical reforming catalyst particles used to react a petroleum charge stream under conventional reforming conditions. Catalytic reforming cracking of hydrocarbon streams has generally been performed using platinum-containing catalysts in fixed bed units, and catalysts of this type are well known in the art. Typical platinum-alumina halogen catalysts used or which can be used in the present apparatus are 0.8-3.2 mm in diameter and preferably completely spherical to provide a free flow that does not readily bind or block the sinking column system. The catalyst is in particular of the type * 59117 in which platinum is combined with alumina in an amount between about 0.1 and about 3¾ of platinum by weight of alumina. Halogen, such as fluorine or chlorine, or a combination of the two, may also be present at about 0.1 to 8% by weight of the alumina. The commonly used halogen is chlorine and is present at about 0.05-5 0,0 by weight of alumina. In the reforming zone, there is usually a substantial amount of hydrogen that can range from a molar ratio of about 1: 1 to about 10: 1, and thus carbon formation is relatively slow and the catalyst can be used for relatively long periods of time. However, the catalyst parts charged to the present resuscitation unit have an order of magnitude of 2-5¾ carbon by weight of the catalyst.

As for the internal structure of the elongate vertical resuscitation unit, different types of screens or shredded plates can be used to channel the catalyst particles into a narrow confined column so that such particles can be contacted in successive stages with transverse gaseous or vapor treatment streams. The perforated screen or plate may comprise two spaced apart flat members for forming a substantially rectangular descending sub-column, but in a preferred embodiment two cylindrical screens are used, one of which is concentrically inside the other to provide an annular sub-sub-column. The vapor or gaseous streams to be contacted also preferably flow from the outside inwards through the mattress to achieve the desired treatment of these particles. With respect to the screen structure, in one preferred structure, each particle delimiting screen is made using a wedge-shaped wire whose cross-sectional area decreases away from the partial side of the screen. That is, the particles flow downward along the surface of a screen where the wider portion of the wedge-shaped wire always contacts the particles, so that if any particle or part thereof passes through the gaps between the yarns, it travels freely outward from the particle boundary zone to an increasing cross-sectional area.

In one preferred resuscitation column structure, thermal expansion of the internal screen members and tubular members has been taken into account to prevent any possible deformation that could otherwise occur under varying temperature conditions. In other words, in a preferred embodiment of the invention, the expansion of the catalyst suspension-limiting screen members from the top of the unit chamber as well as any internal tubular member is taken into account, with thermal movements being received vertically at the bottom of the elongate chamber. In another preferred construction, all of the inner zones can be assembled and fitted through a removable end portion of the chamber.

The apparatus of the invention using an elongate vertically oriented unit chamber with a descending column of catalyst particles may also include means for supplying various regeneration streams to successive contact zones as well as means for circulating most of the contact streams through the unit chamber. That is, it has means for scrubbing the combustion gas stream exiting the upper coal combustion zone to primarily remove sulfur dioxide, after which most of the stream is returned to the supply line of the coal combustion zone under controlled oxygen content conditions. In connection with the vertical unit chamber, there may also be means for removing the chlorine-containing contact stream from the halogenation zone and for adding steam and additional chlorine thereto before reheating and circulating to the halogenation zone feeders.

The invention will be described in more detail below with reference to the accompanying drawings, which show a system which is particularly suitable for regenerating a platinum-containing reforming catalyst.

In the drawings, Figure 1 shows a schematic flow system using a vertically elongated unit chamber within which a column of catalyst particles sinks.

Fig. 2 is a sectional plan view taken along line 2-2 in Fig. 1, showing that the sunken column of catalyst particles is in the form of a thin mattress spaced apart by screen members.

Figure 3 is a sectional elevational view of a preferred embodiment of a unit resuscitation chamber in which a submerged catalyst is sandwiched between cylindrical screen members to provide an annular pillar.

Fig. M of the drawing shows an enlarged sectional view of the concentric arrangement of the screen members, sectioned along the line ^ -4 in Fig. 3 ·

Fig. 5 is a partial vertical view showing in particular the use of a wedge-shaped wire to form the screen members of the unit, cut along line 5-5 in Fig. 4.

In particular, Figures 1 and 2 of the drawing show a vertically elongated column 1 with a plurality of contact zones for the recovery of spent catalyst particles fed to the top of the chamber via an inlet pipe 2. According to the present invention, the inner screens or perforated plates such as 3 and 4 are spaced apart to provide a relatively thin sinking sub-column 5 which moves intermittently or continuously by gravity from the top of the chamber to the outlet end 6. This embodiment has an upper elongate carbon combustion zone 7 is shorter than the upper zone, especially when the contact time is generally less than that required in the coal combustion zone. Below the lower end of the chamber 1 and connected to the outlet end 6 is a drying chamber 9 for receiving dry air from a pipe 10 with a control valve 11 for distribution through a torn ring or other distribution member 12. Air, vented vapors and gases from chamber 9 can flow from the top of the chamber to the lower opening 6 of the chamber 1 and through the bypass pipe 6 'and thus to the parts in the halogenation zone 8 as well as the combustion zone 7. If gaseous flow from the chamber 9 is not prevented in fact, such a chamber can alternatively be fitted directly to the lower part of the elongate chamber 1.

The recirculation of the exhaust gas stream to the lower part of the coal combustion zone 7 by the feed member 13 is schematically shown so that the gas stream passes transversely below the partition 15 'and through the sinking sub-column 5, The latter continues as a pipeline 17 with a valve 17 'and joins a scrubber 18 to remove sulfur dioxide that may be present in the combustion products stream. The scrubber 18 is of the venturi type which receives the recycled alkaline stream through a pipe 19 and a condenser 20 as well as a pipe 21 and a valve 22 which in turn receives a liquid from a pump member 23 and a pipe 26 connected to the lower part of the base chamber 25. Of course, the present resuscitation system is not limited to the use of any washer, as other downstream and countercurrent washers may be well used. In this case, however, the exhaust gas stream from the scrubber 18 and the base flow in the pipe 2A to the base separation chamber 25, the separated base flowing to the exhaust pipe 26 and the washed combustion gas to the pump 23 through the mist extractor 27 to the line 28, purifier 29 and pipe 30. 7 591 1 7 is a control valve 31 »which re-supplies the gases to the supply member 13. Some of the combustion gases are removed from the system via a ventilation pipe 32 with a control valve 33.

It should be noted that when using sulfur-poor feeds and when the gaming gases do not contain a lot of sulfur dioxide, the entire base wash operation can be eliminated. In this case, the valve 17 'is closed and the gas flow is circulated in the pipe 63 with the valve 63' to the condenser 20 *, then to the pipes 28 'and 28 and to the fan 29 · Some exhaust gases can also be vented through the pipe 64 with the valve 64'.

The lower halogenation zone 8, separated from the upper combustion zone 7 by partition walls 34, has means for supplying a recovery stream, such as chlorine, with steam and air via a feeder 35 · Thus, the addition of halogen may also be part of the system in contact with the transverse flow. If desired, and as shown in this embodiment, below the septum 38 there is a transverse initial flow to zone 36 and then a second transverse flow to zone 37 above the septum plate 38, whereby the resulting unadsorbed halogen and vapor can be removed from the particles descending through the pillar 5 past the partitions 34 and reaching the coal combustion zone 7 ·

The preferred system has means for recirculating the steam and halogen stream from the outlet 39 by passing this stream to a pipe 40 connected to a blower 41 which discharges it to a pipe 42 connected to a heating device or heat exchanger 43. The latter is connected to and discharges the flow to the halogenation zone 8. The supply pipe 44 provided with the control valve 45 includes means for supplying chlorine and / or other halogen to the system via the pipe 42 and the pipeline 46 provided with the control valve 47 includes means for supplying additional steam to the resuscitation system. In the heating device 43, hot gases or vapors can be used in the heat exchange with the halogen-steam air stream. However, electric heating or other suitable means of increasing heat may well be used in this system.

To regenerate the reforming catalyst, before returning it to the reforming reactor, an additional step is required in which the substantially 8 5911 7 carbon-free re-halogenated particles are finally reduced in the presence of hydrogen or other suitable reducing agent at a high temperature of 310-650 ° C for a sufficient time. In the embodiment schematically shown in Figure 1, at its lower part, there is a reduction step in which hydrogen is mixed with the catalyst particles flowing through the heating zone. When hydrogen is used, it has means to prevent it from flowing into the halogenation zone and the coal combustion zone. Thus, in the present improved system, the recovered particles move to the reduction stage through a sealing tank or other similar device that prevents gas from flowing from one zone to another. In it, the dry catalyst particles pass from the lower part of the chamber 9 by means of a discharge member * 48 to the valve member 9 and then to the shut-off tank 50. From the latter, particles can be periodically removed by valve 51 to tank 52. The particles can also be cleaned in the shut-off zone. In the case shown, the catalyst particles are removed from the lifting tank 52 by fluidized lifting media, using hydrogen fed through the feed pipe 53 and the valve 51 *, to an internal lifting pipe 55 extending upwards to the pipe 56 and the heating-reduction zone 57. The latter has 58 and a valve 59 to provide indirect heat transfer with the inner tube 60 to reduce the catalyst particles at high temperature in the presence of hydrogen as the reducing medium. The heat transfer fluid from the heating device 57 can be discharged by a pipe 61, the outlet pipe 62 removing the completely reduced and regenerated catalyst for reuse in the reforming reactor.

It should be noted that the reduction arrangement shown is only schematic and that other mechanical devices for introducing the hydrogen catalyst mixture into a suitable heating and reduction zone can be used in the system. For example, the even lower reduction zone can be arranged directly below the drying zone 9 and the sealing tank 50 so that the catalyst particles flow by gravity and these particles are brought into contact by a cross-flow arrangement or a fluidized contact in which the reduction flow causes fluidization. In another embodiment, the recovered but non-reduced catalyst particles can be fed to the reforming reactor at least immediately adjacent to the reforming reactor, where the actual heating and high temperature reduction is provided by the heat given off by the hydrocarbon vapors fed to the reforming reactor. In any case, the reduction step involves mixing hydrogen with the catalyst particles under reducing conditions at high temperature for a time sufficient to complete the desired reduction step before feeding the particles to the actual hydrocarbon reaction zone, which is usually at least about 2 hours.

Figures 3, 4 and 5 of the drawing show a preferred embodiment for constructing an elongate chamber containing a column of spent catalyst particles which sinks through a plurality of recovery steps. This preferred embodiment has an elongate cylindrical chamber 65 with gas and steam supply devices 66 and 67 and a removable upper end zone 68 through which certain inner zones can be fitted into the chamber and removed from inside the chamber. The larger diameter or outer cylindrical screen member 69 inside the chamber 65 has an upper flange 70 disposed between the flange portions 71 and 72 which are part of the end zone 68 and the chamber 65. The flange 70 fits the screen member 69 at the end of the chamber , which forces all inlet gases to flow through the annular catalyst bed. The inner smaller-diameter screen member 73 is also spaced from the screen member 69 but secured to the top of the removable end zone 68 to provide an annular space for a sinking sub-column 74 communicating with an upper catalyst receiving zone 75 which in turn receives feed from a feedpipe 76 and 77.

It should be noted that the lower ends of the screen members 69 and 73 are free to move and elongate downward under high temperature conditions and to move both as they expand and contract without causing bending in either case. It should also be noted that the elongate chamber 65 has a smaller diameter wall zone 78 sized to provide a sliding fit in the zone 79 to the lower end portion of the screen member 69 to guide the latter lower end and provide a catalyst seal. The lower end of the screen member 73 has suitable guide vanes 80 to keep this member concentrically inside the outer screen member 69.

At the upper end of the chamber, above the removable end zone 68, the open end portion 10 5 91 1 7 of the inner cylindrical screen member 73 is connected to an outlet zone 81, which in this case is formed into a substantially 90 ° bend with a degassing opening 82. The inner screen member 73 has an elongate axial a degassing line 83 extending through the wall of the conduction zone zone 111 and opening into a different or different degassing portion 8. The inner tube 83 is preferably conical, forming a relatively large open end zone 85 for receiving gas and vapors from the lower halogenation zone of the elongate chamber 65 and removing them to the outlet zone 8. The smaller diameter top of the tube 83 forms a gas collection space 86 around it, the cross-sectional area of which increases downstream, whereby a gas stream passing from the inlet pipe 66 to the annular zone 87 and then through the catalyst bed 7 collects in this inner zone 86.

In the space around the outer screen member 69, there is a septum member in the form of an annular ring 88 to provide an upper interior to the chamber 65> which may be designated as a carbon combustion zone. This zone generally includes the main part of the submerged annular pillar 7H of the catalyst particles, the pillar part 89 below it forming a halogenation zone. In this latter zone, the halogen-vapor air stream passed through the feed member 67 flows to the annular distribution zone 90, then through the catalyst column 89 to the inner collection space 91 and the excess halogens from the latter stage and steam flow upwards through the inner tube 83.

In the lowest zone of the vertical chamber 65, surrounded by the wall zone 78, the catalyst particles are assembled in a mattress 92 sinking from the lower end of the annular column 89 so that they can be dried before being removed from the lower end opening 93. The latter is connected to the feed opening 95 along the lower side part of the chamber wall 78. The air from the mattress 92 flows partly to the partial column 89> but most of it flows past it to the zone 90 for recirculation therein and from the upper part of the halogenation zone 85 to the lower part of the combustion distribution zone 87.

The resulting dried and substantially regenerated catalyst particles * 'are periodically or continuously removed from the lower end of chamber 65 by removal means 93 »as shown, and may then be fed to a suitable reduction zone through a particulate permeation restrictor to prevent the passage of gas or vapors. Such a device is usually a shut-off tank, valves or the like, although other means of preventing hydrogen backflow may be used. As noted above, the catalyst particles are preferably small spheres in nature so that they can flow freely through the entire vertical column as well as through the lower moving mattress zone 92, which has a drying zone. To prevent sticking and distribute the particle stream evenly, there is a conical particle baffle 96 immediately above the lower outlet 93.

The size of any hole or opening in the perforated plate or screen members 69 and 73 of this unit is proportional to the size of the particles used in the reaction system. That is, when the catalyst particles are of the order of 1.6 mm in diameter, the screen openings must be slightly smaller to prevent particle losses through the screen members as these particles move by gravity in the sinking column in the present unit system. In a preferred embodiment of the invention, specially shaped screen members are used in each screen member 69 and 73, in which the wire is wedge-shaped. This type of screen can be formed by helically winding steel wire around a plurality of spaced longitudinal members to provide a continuous open gap. The gap is, of course, sized to prevent the catalyst member from passing through it.

As best seen in Figures 4 and 5, they show on an enlarged scale the use of outer and inner screen members 73 and 69 having a wedge-shaped wire structure. The inner screen 73 is formed of a helically twisted wedge-shaped yarn 97 supported by spaced vertical bars 98 into a perforated screen structure, as disclosed in U.S. Patent No. 2,046,458. The screen 69 is again made so that the wedge-shaped yarn 99 runs vertically over the support rods 100. The wedge wires in both screens 69 and 73 are preferably oriented vertically to minimize abrasion of the catalyst particles as they sink downward. In particular, however, it should be noted that the wide side portions of the wedge-shaped wires 99 and 97 are arranged inwardly toward the sinking pillar of the catalyst particles. This fit prevents the particles from sticking and clogging the space or gaps between adjacent screens.

12 59117

In the event that one of the particles is small enough to pass through the space between the wedge-shaped screens, the increased cross-sectional area of the slits between the screen members allows the particles to pass through the gap without sticking or clogging.

Unit operation of the ventilation system

To give an example of the operation of the unit system of the present invention, it is assumed that the contact time of the catalyst particles in the carbon combustion zone should be about 2 hours when chlorination or halogenation requires an hourly contact time, so that an annular mattress zone 89 opposite the inlet zone 90, which in turn communicates with the feed members 67. At the same time, in the drying zone 92 requiring a contact time of about two hours, the height of the mattress portion 92 must be adjusted relative to its cross-sectional area so that all catalyst parts moving through it need two hours. .

As for the bottom of the column, a heated stream of dry air is fed to it by a feed member 95 and a dispenser 94 so that drying takes place in a temperature range of 430 to 540 ° C. The amount of air supplied is in fact determined by the oxygen demand of the coal combustion zone, which in this case provides a gas volume rate per hour of the order of 130-170. In this embodiment, air flows upward through the halogenation zone to the feed pipe 85 for recirculation, although a portion of the desired size flows transversely in the halogenation zone 85 to the zone 86 to supply air and return to the coal combustion zone. Although most of the air flow exits through the tube 83 and the outlet 84 from which it is recycled back to the halogenation zone, as shown in Figure 1, the portion entering the mattress zone 74 donates oxygen to the combustion of coal in this upper zone.

The halogen vapor stream is fed from the feed port 67 transversely through the column portion 89 to adsorb halogen to the catalyst particles and redistribute the platinum content to the minimum crystallite sizes in the particles. Any excess steam and halogen flow upward through the outlet pipe 83 or for recycling, as mentioned above. To the chlorine-containing catalyst 13,591 1 7 of chlorine is added in such an amount that about 2.5 moles per hour are maintained in the stream in contact with the catalyst at a temperature of about 500 ° C. The steam is mixed with chlorine at a temperature of about 250 ° C and at the same time, the volume of the combined gas streams providing a relatively high gas volume rate per hour of the order of 4700.

At the top of the column, where the oxygen-controlled stream provides substantial removal or incineration of carbon deposited on the spent catalyst particles, there is a recirculated combustion product stream maintained at 440-500 ° C with a gas volume rate per hour of the order of magnitude 4700. shown in Figure 1 and the oxygen content of the stream 66 to be fed to the coal combustion stream is of the order of about 0.7¾.

It should be noted that the above operation example showing different temperatures and amounts is only an example and does not limit the invention in any way, especially since the present improved system can be used in any given desired temperature range within the limits of the building materials. The recovery streams and contact times may also be varied to suit a particular reforming catalyst and a particular amount of carbon or other state of the catalyst exiting the hydrocarbon reaction zone. That is, the amount of carbon, chlorine, etc. leaving the reformer can be varied from moment to moment or varied in different units using different feedstocks containing different large amounts of sulfur, etc., so that the recovery conditions vary accordingly.

Claims (7)

A process for the continuous regeneration of carbonaceous catalyst particles used in hydrocarbon reforming cracking, characterized in that (a) the particles used are passed to the top of a closed regeneration zone, (b) said catalyst is passed through at least a portion of this zone as an elongate moving mattress the concentrated gas stream is contacted with a column to burn and remove carbon from said particles, (d) the resulting particles are fed in a continuous moving mattress-like column to the lower part of the regeneration zone and contacted with a halogen-containing gas stream to add halogen thereto, (e) then halogenated to a drying zone where they are contacted with a stream of dry air to remove excess gaseous constituents, allowing the latter gas stream to mix in the previous stage of contact through the particles vi halogen-containing gas stream. An apparatus for the continuous regeneration of the carbonaceous catalyst particles used in the reforming cracking of hydrocarbons according to claim 1, comprising a chamber bounded on one side by a coaxial screen with a gas inlet and on the other side by an exhaust gas outlet, characterized in that the column (1, 65) extends below the coal combustion zone (5, 7 * 0) and thus forms a lower zone (8, 89), below it and the partition wall (3 * 0 88) separating the coal combustion zone, which is outside the catalyst chamber, that the column has a halogen-containing gas inlet (35, 67) and a spent halogen gas outlet on the outflow side of the screens (39, 85) and coaxial screens (3, 4; 69, 73), which passes continuously through the partial column (5, 7 * 0, the carbon combustion zone (5, 7 * 0) and the halogenation zone (8, 89). Device according to Claim 2, characterized in that the carbon flue gas outlet line (16) is connected to an alkali metal liquor scrubber (18) and that the scrubber outlet side of the scrubber (18) is connected to the flue gas inlet connection (13). Device according to claim 2, characterized by a recirculation system (40-43) connected to the halogenation zone (8), having a water vapor inlet line (46), a halogen inlet line (44) and heating devices (43). Apparatus according to claims 2-4, characterized by a catalyst chamber consisting of two screens (69, 73) arranged centrally with respect to each other, the partition (88) dividing the outer annular space between the screens and the column into a combustion zone and a halogenation zone, an inner flue the coil space (86) is connected to the carbon flue gas outlet line (81) and an upwardly tapering halogenation gas outlet line (83) is provided inside the inner cylinder space (86), the inlet opening (85) of which is below the partition wall (88). Device according to Claim 2, characterized in that the halogenation gas outlet (85) extends upwards inside the inner cylindrical screen (73) up to the outlet (84) above the column (65). Device according to Claim 2, characterized in that the coaxial screens (3, 4; 69, 73) consist of wedges (97, 99) with a cross-section and in that the wider wedge surfaces of the screen yarns are directed towards the catalyst column (74).