Processes For The Continuous Regeneration Of A Catalyst (United States Patent Application 20150290636 UOP LLC)

CATEGORY: CATALYSIS: REGENERATION 
Processes For The Continuous Regeneration Of A Catalyst (United States Patent Application 20150290636 UOP LLC)
United States Patent Application 20150290636 UOP LLC
October 15, 2015
Assignee: UOP LLC
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.
FIELD OF THE INVENTION
[0001] This invention relates generally to the regeneration of hydrocarbon conversion catalysts in the presence of a halogen-containing material.
BACKGROUND OF THE INVENTION
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.sub.5+ yield, hydrogen product yield and low activity.
[0011] 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.
[0012] Therefore, there remains a need for effective and efficient processes for regenerating catalyst.
SUMMARY OF THE INVENTION
[0013] The present invention is directed to providing effective and efficient processes for regenerating catalyst.
[0014] 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.
[0015] 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.
[0016] It is also contemplated that in some embodiments the cooling zone the catalyst is cooled to a temperature at least 100.degree. 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.degree. C. to 70.degree. C.
[0017] In some embodiments, a chloride content on catalyst exiting the cooling zone is higher than a chloride content on catalyst entering the cooling zone.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] In some embodiments an amount of recovered chloride may be selectively controlled independently of a flow of the catalyst.
[0028] 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.
[0029] 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.
[0030] Additional objects, embodiments, and details of the invention are set forth in the following detailed description of the invention.
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