Abstract:
A process for regenerating a catalyst used in a reaction zone. In a regeneration zone, the catalyst may be cooled before passing into a chloride rich zone. The regeneration zone may also receive a heated ambient oxygen in a catalyst heating zone. The regeneration zone may also receive recovered chloride from a chloride recovering zone which removes and recovers chloride from regeneration gas taken from the regeneration zone. Heated ambient oxygen may also be introduced into a chlorination zone.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the regeneration of hydrocarbon conversion catalysts in the presence of a halogen-containing material. 
     BACKGROUND OF THE INVENTION 
     Numerous hydrocarbon conversion processes are widely used to alter the structure or properties of hydrocarbon streams. Such processes include isomerization from straight chain paraffinic or olefinic hydrocarbons to more highly branched hydrocarbons, dehydrogenation for producing olefinic or aromatic compounds, reforming to produce aromatics and motor fuels, alkylation to produce commodity chemicals and motor fuels, transalkylation, and others. 
     Many such processes use catalysts to promote hydrocarbon conversion reactions. These catalysts tend to deactivate for a variety of reasons, including the deposition of carbonaceous material or coke upon the catalyst, sintering or agglomeration or poisoning of catalytic metals on the catalyst, and/or loss of catalytic metal promoters such as halogens. Consequently, these catalysts are typically reactivated in a process called regeneration. 
     Reactivation can include, for example, removing coke from the catalyst by burning, redispersing catalytic metals such as platinum on the catalyst, oxidizing such catalytic metals, reducing such catalytic metals, replenishing catalytic promoters such as chloride on the catalyst, and drying the catalyst. For example, U.S. Pat. No. 6,153,091 discloses a method for regenerating spent catalyst. 
     In a some regeneration processes, a catalyst is passed from a reaction zone to a regeneration zone which may include a burn zone, a catalyst heating zone, a chlorination zone, a catalyst drying zone, and a catalyst cooling zone, and wherein the catalyst includes coke; burning off the coke from the catalyst in the burn zone; increasing a temperature of the catalyst in the catalyst heating zone; dispersing the a metal on the catalyst in the chlorination zone, replacing a chloride on the catalyst or both; drying the catalyst in the catalyst drying zone; cooling the catalyst in the catalyst cooling zone. 
     However, some regeneration processes/systems may require a higher temperature to achieve an optimal desired temperature in the chlorination zone. Therefore, it would be desirable to provide a process which allows for a desired temperature (or range) in the chlorination zone to be achieved. 
     Additionally, some regeneration processes may require a higher temperature to achieve an optimal drying zone temperature. Therefore, it would be desirable to provide a process which allows for desired temperature in the drying zone to be achieved. 
     Furthermore, some regeneration processes/systems rely on electric heaters for oxygen supplied to the system. Therefore, it would be desirable to provide a process which allows for the regeneration process to be run with a wider range of catalyst coke values. 
     Additionally, it would be desirable to provide a process which allows for the proper amount of chlorine to be introduced to disperse the metals on the catalyst, without increasing the amount of chloride on the regenerated catalyst. In other words, it would be desirable to have a process in which the chloride level of the catalyst is decoupled from the chorine used for dispersion so that the process can operate at a lower level of chloride while achieving a sufficient metal dispersion. 
     Furthermore, some current designs may not allow metal to be dispersed in the chlorination zone or drying zone during some modes of operation. More specifically, in a “black burn” mode the catalyst has high levels of coke and only nitrogen is injected into these two zones. Additionally, no chloride is injected into the regenerator. This operation condition prohibits metal (including platinum) dispersion during the black burn mode resulting in decline in catalyst performance, loss of C 5 + yield, hydrogen product yield and low activity. 
     Furthermore, during other operation modes, coke slippage or slightly higher coked catalyst passing into the chlorination zone, may result in poor metal dispersion, catalyst damage, catalyst fines generation, and equipment fouling. These can shorten the process turnaround interval leading to potential of a unit shutdown resulting in loss of production in the reforming unit. Therefore, it would be desirable for a process in which metal dispersion occurs during various operation modes. It would also be desirable to provide a system which also increases the coke burn to avoid coked catalyst from burning in the chlorination zone. 
     Therefore, there remains a need for effective and efficient processes for regenerating catalyst. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to providing effective and efficient processes for regenerating catalyst. 
     Accordingly, in one aspect of the present invention, the present invention provides a process for the continuous regeneration of a catalyst in which a catalyst is passed from a reaction zone to a regeneration zone, wherein the regeneration zone includes at least a burn zone to remove coke from the catalyst, the catalyst is recycled from the regeneration zone back to the reaction zone, and wherein the catalyst is cooled in a catalyst cooling zone after the catalyst exits the burn zone while the catalyst passes through a chloride, and, a metal is dispersed on the catalyst with chloride in a chlorination zone after the catalyst has left the catalyst cooling zone. 
     It is contemplated that the chlorination zone is disposed below the burn zone so that chloride in the chlorination zone flows upwards towards the burn zone. 
     It is also contemplated that in some embodiments the cooling zone the catalyst is cooled to a temperature at least 100° C. lower than a temperature of the catalyst as the catalyst enters the chlorination zone. Additionally or alternatively, in the cooling zone the catalyst is cooled to a temperature between approximately 350° C. to 70° C. 
     In some embodiments, a chloride content on catalyst exiting the cooling zone is higher than a chloride content on catalyst entering the cooling zone. 
     In another aspect of the present invention, a process for the continuous regeneration of a catalyst is provided which includes: passing a catalyst from a reaction zone to a regeneration zone, wherein the regeneration zone includes at least a burn zone to remove coke from the catalyst; recycling the catalyst from the regeneration zone back to the reaction zone; dispersing a metal on the catalyst in a chlorination zone of the regeneration zone; drying the catalyst in a catalyst drying zone of the regeneration zone, wherein catalyst drying zone receives a heated ambient oxygen; removing a portion of the heated ambient oxygen from the catalyst drying zone; passing the removed portion of the heated ambient oxygen to an oxygen heating zone; heating the removed portion of the heated ambient oxygen in the oxygen heating zone to provide a reheated ambient oxygen; and, passing the reheated ambient oxygen into the chlorination zone, and wherein a flow rate of the heated ambient oxygen is capable of being maintained while a flow rate of the reheated ambient oxygen is decreased. 
     In some embodiments, chloride is mixed with the reheated ambient oxygen and the mixture of chloride and the reheated ambient oxygen is passed into the chlorination zone. 
     In some embodiments, an operating parameter of the oxygen heating zone is controlled based upon the temperature of the chlorination zone. The operating parameter may be a temperature or a flow rate. 
     In still other embodiments of the present invention, process utilizing this aspect of the present invention may also include: cooling the catalyst in a catalyst cooling zone of the regeneration zone, wherein the catalyst cooling zone receives an ambient oxygen from outside of the regeneration zone; removing a portion of the ambient oxygen from the catalyst cooling zone; passing the removed portion of the ambient oxygen to a second oxygen heating zone; and, heating the removed portion in the second oxygen heating zone to provide the heated ambient oxygen which is passed to the catalyst drying zone. 
     In further embodiments of the present invention, the processes may include: passing a portion of the reheated ambient oxygen to a compression zone to provide a compressed ambient oxygen; mixing the compressed ambient oxygen with an additional ambient oxygen from outside of the regeneration zone; and, passing a mixture of the compressed ambient oxygen and the additional ambient oxygen to the catalyst cooling zone. 
     In another aspect of the present invention, another process is provided for the regeneration of a catalyst which includes: passing a catalyst from a reaction zone to a regeneration zone, wherein the regeneration zone includes at least a burn zone to remove coke from the catalyst; recycling the catalyst from the regeneration zone back to the reaction zone; heating the catalyst in a catalyst heating zone so that a temperature of the catalyst has increased at least after the catalyst has flowed out of the burn zone; and, passing a heated ambient oxygen to the catalyst heating zone to increase the temperature in the catalyst heating zone so that the temperature of the catalyst increases. 
     In some embodiments, a flow of the heated ambient oxygen is directed into the catalyst heating zone with an air flow direction device. The air flow direction device may be a baffle. Additionally, the air flow direction device may direct the split portion of the ambient oxygen in a direction generally parallel to a flow of the catalyst through the catalyst heating zone. 
     In some embodiments, a chloride is mixed with the heated ambient oxygen and the mixture of chloride and the heated ambient oxygen is passed into the catalyst heating zone. Additionally, nitrogen may be passed into the regeneration zone below the catalyst heating zone. 
     In still another aspect of the present invention, a process for the continuous regeneration of a catalyst includes: passing a catalyst from a reaction zone to a regeneration zone, wherein the regeneration zone includes at least a burn zone to remove coke from the catalyst; recycling the catalyst from the regeneration zone back to the reaction zone; removing a regeneration gas from the regeneration zone; recovering a chloride from the regeneration gas; and, recycling the recovered chloride back to the regeneration zone. 
     In some embodiments an amount of recovered chloride may be selectively controlled independently of a flow of the catalyst. 
     In at least one embodiment, the recovered chloride is recycled back to the burn zone of the regeneration zone. In some embodiments, the recovered chloride is recycled back to at least one of the following zones in the regeneration zone: the burn zone; a chlorination zone; and, a catalyst drying zone. Any amounts of recovered chloride may be selectively controlled. 
     In yet another aspect of the present invention, a regeneration zone includes at least two, at least three, or all of the above described aspects of the present invention. 
     Additional objects, embodiments, and details of the invention are set forth in the following detailed description of the invention. 
    
    
     
       DETAILED DESCRIPTION OF THE DRAWING 
       The drawings are simplified process flow diagrams in which: 
         FIG. 1  shows a process according to one or more aspects of the present invention for the regeneration of a catalyst; 
         FIG. 2  shows another process according to one or more aspects of the present invention for the regeneration of a catalyst; 
         FIG. 3  shows yet another process according to one or more aspects of the present invention for the regeneration of a catalyst; and, 
         FIG. 4  shows still another process according to one or more aspects of the present invention for the regeneration of a catalyst. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One or more processes have been developed for the regeneration of a catalyst used in a catalytic reforming reaction. 
     A catalytic reforming reaction is normally effected in the presence of catalyst particles comprised of one or more Group VIII noble metals (e.g., platinum, iridium, rhodium, palladium) and a halogen combined with a porous carrier, such as a refractory inorganic oxide. The halogen is normally chloride. Alumina is a commonly used carrier. The preferred alumina materials are known as the gamma, eta and theta alumina with gamma and eta alumina giving the best results. An important property related to the performance of the catalyst is the surface area of the carrier. 
     Catalyst particles are usually cylindrical or spheroidal, having a diameter of from about 1/16th to about ⅛th inch (1.5-3.1 mm), though they may be as large as ¼th inch (6.35 mm). When cylindrical, the catalyst particles have a length of from about ⅛th to about ¼th inch (3.1-6.35 mm). In a particular catalyst bed, however, it is desirable to use catalyst particles which fall in a relatively narrow size range. A preferred catalyst particle diameter is 1/16th inch (3.1 mm). During the course of a reforming reaction, catalyst particles become deactivated as a result of mechanisms such as the deposition of coke on the particles; that is, after a period of time in use, the ability of catalyst particles to promote reforming reactions decreases to the point that the catalyst is no longer useful. The catalyst must be regenerated before it can be reused in a reforming process. 
     Accordingly, in the various aspects of the present invention a catalyst having coke is passed via a line from a reaction zone to a regeneration zone. As will be discussed in more detail below, the regeneration zone may include a tower which may includes, one or more of: a burn zone; a catalyst heating zone; a chlorination zone; a catalyst drying zone; a catalyst cooling zone; or any combination of these zones. The catalyst can be recovered from the cooling zone, subjected to a reduction or other known processing steps, and then recycled back to the reaction zone as regenerated catalyst and reused. 
     Returning to the regeneration zone, the burn zone comprises a portion of the regeneration zone in which coke combustion takes place. Coke which could have accumulated on surfaces of the catalyst because of the reforming reactions can be removed by combustion. Coke is comprised primarily of carbon but is also comprised of a relatively small quantity of hydrogen, generally from 0.5 to 10 wt-% of the coke. The mechanism of coke removal includes oxidation to carbon monoxide, carbon dioxide, and water. The coke content of spent catalyst may be as much as 20% by weight of the catalyst weight, but 5-7% is a more typical amount. Coke is usually oxidized at temperatures approximately in the range of 400° C. to 700° C. As a result of the high temperature, catalyst chloride is quite readily removed from the catalyst during coke combustion. 
     In order to increase the temperature of the catalyst for processing in further zones, the catalyst passes out of the burn zone and may be passed into a catalyst heating zone. In the catalyst heating zone, the catalyst is heated by the gases rising form the lower portions of the regeneration zone (discussed in more detail below). 
     The catalyst may pass from the catalyst heating zone to a chlorination zone. In the chlorination zone, the catalyst metal is dispersed. The dispersion typically involves chlorine or another chloro-species that can be converted in the regeneration zone to chlorine. The chlorine or chloro-species is generally introduced in a small stream of carrier gas that is added to the chlorination zone. Although the actual mechanism by which chlorine disperses catalyst metal is the subject of a variety of theories, it is generally recognized that the metal may be dispersed without increasing the catalyst chloride content. In other words, although the presence of chlorine is a requirement for metal dispersion to occur, once the metal has been dispersed it is not necessary that the catalyst chloride content be maintained above that of the catalyst prior to dispersion. Thus, the agglomerated catalyst can be dispersed without a net increase in the overall chloride content of the catalyst. Notwithstanding same, in the chlorination zone the gas may also replace chloride on the catalyst. 
     After the chlorination zone, the catalyst may pass to a catalyst drying zone in which the catalyst is dried to remove water, and then to a catalyst cooling zone in which the catalyst is cooled to a temperature that is safe for handling and further processing. 
     After cooling, the catalyst may be subjected to subsequent processing such as reduction, and then may be re-used as a catalyst in the reaction zone. 
     Turning to  FIG. 1 , as shown in this aspect of the present invention, a process is directed to the regeneration of catalyst used in a reaction zone  10 . The catalyst is passed, via traditional transportation devices and means, to a regeneration zone  20  which may include one or more regeneration towers  22 . 
     The regeneration zone  20  includes, at least, a burn zone  24 , a top cooling zone  26 , and a chlorination zone  28 . In the burn zone  24 , coke present on the catalyst is burned off, as discussed above. 
     After the catalyst exits the burn zone  24 , it passes into a top cooling zone  26 . In the top cooling zone  26 , chloride, contained in gases flowing upward, contacts the catalyst (which is typically moving in the opposite direction). In this manner, the chloride content on the catalyst as it exits the top cooling zone  26  is higher than the chloride content on the catalyst as it enters the top cooling zone  26 . 
     It is contemplated that in the top cool zone  26  the catalyst cools to a temperature between 350° C. to 70° C. It is also contemplated that in the top cool zone  26  the catalyst cools to a temperature that is at least 100° C. lower than a temperature of the catalyst as the catalyst enters the chlorination zone  28 . 
     In the chlorination zone  28 , the catalyst contacts chloride which acts to re-disperse the metal on the catalyst. 
     Additional zones may also be present in the regeneration zone  20 , including, one or more zones discussed elsewhere in this application, for example, a catalyst reheat zone may disposed after the top cool zone  26  and before the chlorination zone  28 . 
     The catalyst may be recycled back to the reaction zone  10  and re-used in the process. 
     The inclusion of the top cooling zone  26  allows for the chloride content of the catalyst as it passes into the chlorination zone  28  to be increased, at least 0.1% higher, without increasing the overall chloride content in the regeneration zone  20 . More specifically, as the catalyst passes into the top cooling zone  26 , the cooling of the catalyst will result in chloride, from the gas moving upward, depositing on the catalyst. Thus, the amount of chloride on the catalyst as it enters the chlorination zone  28  will be higher. Additionally, chloride will be released by the catalyst as the catalyst is heated in the chlorination zone  28 . This will allow the chloride content of the chlorination zone  28  to be higher without increasing the chloride content of the burn zone  24  or chloride delivery to the regeneration zone  20 . Additionally, the top cool zone  26  will maintain the chloride in the regeneration tower  22 , at least until the concentration of the chloride is high enough that it can pass out of the regeneration zone  20 . 
     In order to cool the catalyst after it leaves the burn zone  24 , the top cooling zone  26  may include direct heat exchanges, indirect heat exchanges with the catalyst moving through cooled tubes, or both. 
     It is also contemplated that this aspect of the invention is combined with, at least one additional aspect of the present invention described herein. 
     As shown in  FIG. 2 , in this aspect of the present invention, another process is directed to the regeneration of catalyst used in a reaction zone  200 . The catalyst is passed, via traditional transportation devices and means, to a regeneration zone  202  which may include one or more regeneration towers  204 . 
     The regeneration zone  202  includes, at least, a burn zone  206 , a chlorination zone  208 , a catalyst drying zone  210 , a catalyst cooling zone  212 . Again, in the burn zone  206 , as discussed above, coke is burned off of the catalyst. In the chlorination zone  208 , chloride re-disperses the metal on the catalyst, chloride content of the catalyst is increased, or both. Finally, in the catalyst drying zone  210 , the catalyst is dried. In the catalyst cooling zone  212 , the catalyst is cooled so that it can be handled by other process devices to transport same. 
     In order to cool the catalyst, ambient oxygen is passed to the regeneration zone  202 , typically to the catalyst cool zone  212 . Since the ambient oxygen will absorb heat from the catalyst (to cool it) it will travel upward. A portion may be removed, for example with a baffle  214 . The removed portion may be passed, via a line  216 , to an oxygen heating zone. The oxygen heating zone  218  may include, for example, an electric heater  220 . The oxygen heating zone  218  heats the ambient oxygen which may be passed to the catalyst drying zone  210 . 
     The heated ambient oxygen will dry the catalyst and continue to travel upwards. Again it may be removed with a baffle  222 , or other devices. Once again the removed portion may be passed, via a line  224 , to another oxygen heating zone  226 . Again this may include an electric heater  228 . This oxygen heating zone  226  reheats the ambient oxygen which may be passed into the chlorination zone  208 . 
     Chloride may be injected into one of the zones in the regeneration zone  202 , and preferably, it may be mixed with the gases entering the various zones discussed above. 
     In at least this aspect of the present invention, a flow rate of the heated ambient oxygen in the catalyst drying zone  210  is capable of being maintained (or adjusted) while a flow rate of the reheated ambient oxygen in the chlorination zone  208  is decreased. This may be accomplished, for example, by splitting a portion of the reheated ambient oxygen and recycling same to the catalyst cooling zone  212 . The split portion preferably passes though a compression zone  230  having, for example, a compressor  232 . It may also be cooled prior to being reintroduced into the catalyst drying zone  212 . 
     Accordingly, the flow of oxygen used to cool and dry the catalyst can be operated in a independently from the amount of gas heating the chlorination zone  208 . Thus, the same amount of the ambient oxygen can be used to cool the catalyst and dry the catalyst while the flow of reheated ambient oxygen is lowered. This would be desirable if, for example, there is low coke amount on the catalyst; yet, the same temperature in the chlorination zone  208  is desired. 
     It is also contemplated to measure the temperature of the chlorination zone  208  and control at least one operating parameter of the oxygen reheating zone  226  based upon the temperature. Such a parameter may be flow, operating temperature, both, or another parameter. 
     Additional zones may also be present in the regeneration zone  202 , including, one or more zones discussed elsewhere herein. 
     The catalyst may be recycled back to the reaction zone  200  and re-used in the process. 
     Again, it is also contemplated that this aspect of the invention is combined with, at least, one additional aspect of the present invention described herein. 
     Turning to  FIG. 3 , as shown in this aspect of the present invention, a process is also directed to the regeneration of catalyst used in a reaction zone  300 . The catalyst is once again passed, via traditional transportation devices and means, to a regeneration zone  302  which may include one or more regeneration towers  304 . 
     The regeneration zone  302  includes, at least, a burn zone  306 , a catalyst heating zone  308 , and chlorination zone  310 . Again, in the burn zone  306  coke present on the catalyst is removed via combustion. While this temperature is sufficiently high to burn most of the catalyst off, it is possible that some heavily coked catalyst may pass from the burn zone  306  to the catalyst heating zone  308 . 
     In the catalyst heating zone  308 , the catalyst typically reaches a temperature so that it may pass to additional zones such as a chlorination zone  310  with a temperature around 400° C. to 600° C. Typically the oxygen content in the catalyst heating zone is approximately 0.7 (mol %). 
     As discussed above, any coke that enters this zone will combust, damaging the catalyst. Accordingly, a regeneration zone may operate in “black burn” mode when the coke level on the catalyst is high and nitrogen may be introduced into the bottom of the tower  304 . However, no chloride will be introduced into the regeneration zone  302 , meaning that catalyst chloride level on the regenerated catalyst will be lower than a desired amount. Additionally, metal dispersion on the regenerated catalyst will be less than ideal. Both of these factors will lower that catalyst efficiency and thus, negatively impact the reaction zone  300  products. 
     Accordingly, for either “black burn” mode or normal (“white burn”) mode, heated ambient oxygen maybe passed into the catalyst heat zone  308 . A heater  312  or other temperature increasing device can be used. 
     In “white burn” operations, the oxygen content in the catalyst heating zone  308  may be increased by approximately 1% (mol) (total 1.7%). Additionally, in “black burn” the oxygen content can be increased to a range between 2 to 10% (mol). The amount of heated ambient oxygen can be selectively controlled by, for example, flow control devices within lines, valves, or other devices. 
     In a preferred embodiment, the flow of the heated ambient oxygen into the catalyst heating zone  308  is directed with an air flow direction device  314 , such as a baffle  316 . It is preferred that the flow direction device  314  directs the flow of the heated ambient oxygen, at least initially, in a direction that is parallel (but opposite) to the flow of catalyst through the regeneration zone  302 . The use of flow direction device  319 , as opposed to, for example, a simple introduction of gaseous flow, allows for a smaller sized (circumference) regeneration zone  308  because it will more evenly disperse the oxygen into the catalyst heating zone  308 . Typically reheat zone  308  is 15% of regeneration zone  306  by size, but it could range from 5% to 25%. 
     Additionally, it is contemplated that in some instances it may be desirable to introduce chloride into the burn zone  306 . Accordingly, a line  318  may be used to combine chloride with the heated ambient oxygen and the mixture may be introduced into the catalyst heating zone  308 . In this manner, if the regeneration zone  302  is operated in “black burn” mode, chloride will still be introduced into the regeneration zone  302  to increase the chloride content of the catalyst and re-disperse the metal on the catalyst. 
     Additional zones may also be present in the regeneration zone  302 , including, one or more zones discussed herein. 
     The catalyst may be recycled back to the reaction zone  300  and re-used in the process. 
     While this and other aspects of the invention may be described with respect to black burn mode, it is also contemplated to utilize same in white burn, or normal operation. 
     Again, it is also contemplated that this aspect of the invention is combined with, at least, one additional aspect of the present invention described herein. 
     Turning to  FIG. 4 , as shown in this aspect of the present invention, another process is shown which is also directed to the regeneration of catalyst used in a reaction zone  400 . The catalyst is once again passed, via traditional transportation devices and means, to a regeneration zone  402  which may include one or more regeneration towers  404 . 
     The regeneration zone  402  includes, at least, a burn zone  406 , a chlorination zone  408 , and a catalyst drying zone  410 . As previously discussed, in the burn zone  406  coke is burned off the catalyst. 
     As discussed herein, chloride may introduced in one or more zones to increase the chloride content on the catalyst, re-disperse the metal on the catalyst, or both. Typically, this will result in the gas at the top of the regeneration tower  404  containing chloride. Some processes pass the catalyst through this gas in an attempt to recover some chloride. While other known processes remove all of the gas and scrub all of the gas to remove the chloride, it was discovered that a recovery process could be utilized to recover and recycle the chloride back to the regeneration zone  402 . 
     Accordingly, at least a portion of the regeneration gas may be taken or removed from the regeneration zone  402 , preferably at the top of regeneration tower  404 , and passed to a chloride recovery zone  412 . A second portion of regeneration gas may be recycled back to the burn zone  406 , for example. 
     In the chloride recovery zone  412 , chloride is recovered from the regeneration gas. The recovered chloride may be recycled back to the regeneration zone  402 , and more specifically may be passed to the burn zone  406 , the chlorination zone  408 , the catalyst drying zone  410 , or any other zone. It is contemplated that any amount of recycled chloride is selectively controlled, for example, with a valve. Such a chloride recovery allows for recovery independent of catalyst flow. Known processes for the recovery of chloride include those described in U.S. Pat. Nos. 6,117,809 and 6,153,091, the entirety of which is incorporated herein by reference. 
     Additional zones may also be present in the regeneration zone  302 , including, one or more zones discussed elsewhere herein. 
     The catalyst may be recycled back to the reaction zone  400  and re-used in the process. 
     Such a process may lower the amount of new chlorine species added to the regeneration zone as well as reduce the chloride species from the regeneration gas. 
     Once again, it is also contemplated that this aspect of the invention is combined with, at least, one additional aspect of the present invention described herein. 
     A process including at least one of the above aspects is beneficial and desirable for the reasons described herein. 
     It should be appreciated and understood by those of ordinary skill in the art that various other components such as valves, pumps, filters, coolers, etc. were not shown in the drawings as it is believed that the specifics of same are well within the knowledge of those of ordinary skill in the art and a description of same is not necessary for practicing or understating the embodiments of the present invention. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.