US-12624296-B2 - Process for regenerating catalyst from a fluidized catalytic process at high pressure

US12624296B2US 12624296 B2US12624296 B2US 12624296B2US-12624296-B2

Abstract

A process for regenerating catalyst from a fluidized catalytic process comprising is disclosed. The process comprises providing an oxygen stream and a preheated carbon dioxide recycle stream and mixing the oxygen stream and the preheated carbon dioxide recycle stream to provide a carbon dioxide rich oxidation stream. The carbon dioxide rich oxidation stream is passed to a regenerator unit to provide a carbon dioxide rich flue gas stream. One or more of a sulfur-containing compound, a nitrogen-containing compound, or both in the carbon dioxide rich flue gas stream is reacted with a reactant in a decontamination reactor to form a reactor effluent stream comprising reactant salt. The reactor effluent stream is filtered to remove the reactant salt and catalyst fines to produce a filtered reactor effluent stream. A carbon dioxide recycle stream is taken from the filtered reactor effluent stream.

Inventors

Anil Nivrutti Pachpande
Yogesh Kumar Gupta
Jan De Ren
Sakthivelan Maadasamy Durai

Assignees

UOP LLC

Dates

Publication Date: 20260512
Application Date: 20230508

Claims (19)

1 . A process for regenerating catalyst from a fluidized catalytic process comprising: providing an oxygen stream and a preheated carbon dioxide recycle stream; mixing said oxygen stream and said preheated carbon dioxide recycle stream to provide a carbon dioxide rich oxidation stream; passing said carbon dioxide rich oxidation stream to a regenerator unit to provide a carbon dioxide rich flue gas stream; reacting one or more of a sulfur-containing compound, a nitrogen-containing compound, or both in said carbon dioxide rich flue gas stream with a reactant in a decontamination reactor to form a reactor effluent stream comprising reactant salt; filtering the reactor effluent stream to remove the reactant salt and catalyst fines to produce a filtered reactor effluent stream; compressing said filtered reactor effluent stream to provide a compressed filtered reactor effluent stream; and recycling said compressed filtered reactor effluent stream to said regenerator unit.
2 . The process of claim 1 further comprising taking a carbon dioxide recycle stream from the filtered reactor effluent stream.
3 . The process of claim 2 further comprising: heat exchanging said filtered reactor effluent stream with said carbon dioxide recycle stream in the heat exchanger to provide said preheated carbon dioxide recycle stream and a partially cooled filtered reactor effluent stream; optionally cooling said partially cooled filtered reactor effluent stream to provide a cooled filtered reactor effluent stream; separating water from said cooled filtered reactor effluent stream to provide a carbon dioxide stream; and separating said carbon dioxide stream into said carbon dioxide recycle stream and a separated carbon dioxide stream.
4 . The process of claim 3 further comprising: compressing said carbon dioxide recycle stream to provide a compressed carbon dioxide recycle stream; passing the compressed carbon dioxide recycle stream to a low-pressure steam generator to provide a low-pressure steam stream and a partially cooled carbon dioxide recycle stream; cooling said partially cooled carbon dioxide recycle stream to provide a cooled carbon dioxide recycle stream; separating water from the cooled carbon dioxide recycle stream to provide a dry carbon dioxide recycle stream; preheating said dry carbon dioxide recycle stream by heat exchanging said filtered reactor effluent stream with said dry carbon dioxide recycle stream to provide a preheated dry carbon dioxide recycle stream; and passing said preheated dry carbon dioxide recycle stream to said regenerator unit.
5 . The process of claim 3 further comprising: heating said recycle carbon dioxide stream to provide a warm carbon dioxide recycle stream; and recycling said warm carbon dioxide recycle stream to said regenerator unit.
6 . The process of claim 3 further comprising passing said separated carbon dioxide stream to a methanol synthesis unit for providing a methanol stream.
7 . The process of claim 1 wherein the reactant is in dry form.
8 . The process of claim 1 wherein said decontamination reactor operates at a temperature from about 200° C. to about 600° C. for reacting one or more of the sulfur-containing compound, the nitrogen-containing compound, or both in said carbon dioxide rich flue gas stream with the reactant.
9 . The process of claim 1 wherein the carbon dioxide rich oxidation stream comprises an oxygen concentration of no more than 30 mole %.
10 . The process of claim 1 wherein said oxygen stream is provided from an electrolyzer or an air separation unit.
11 . The process of claim 1 further comprising transferring heat from said carbon dioxide rich flue gas stream to a boiler feed water stream in a heat recovery section to form a partially cooled carbon dioxide rich flue gas stream and a steam stream.
12 . The process of claim 11 , wherein said heat recovery section is a heat recovery steam generator (HRSG) comprising: transferring heat from said carbon dioxide rich flue gas stream to a boiler feed water stream in said HRSG to form said partially cooled carbon dioxide rich flue gas stream and said steam stream; and passing the partially cooled carbon dioxide rich flue gas stream to the decontamination reactor.
13 . The process of claim 12 wherein the HRSG comprises a superheated steam section and a saturated steam section and further comprising: passing said carbon dioxide rich flue gas stream into the superheated steam section of said HRSG to produce a superheated steam stream and a heat exchanged carbon dioxide rich flue gas stream, passing a boiler feed water stream and the heat exchanged carbon dioxide rich flue gas stream into the saturated steam section of the HRSG to form said partially cooled carbon dioxide rich flue gas stream and a saturated steam stream; introducing at least a portion of the saturated steam stream into the superheated steam section of the HRSG; and superheating the saturated steam stream with said carbon dioxide rich flue gas stream to produce the superheated steam stream.
14 . The process of claim 11 further comprising: separating said carbon dioxide rich oxidation stream into a first portion and a second portion; passing the first portion of carbon dioxide rich oxidation stream to said regenerator unit; and passing the second portion of carbon dioxide rich oxidation stream to said heat recovery section.
15 . The process of claim 11 wherein said heat recovery section is a heat recovery section of a CO combustor.
16 . The process of claim 1 wherein said fluidized catalytic process is selected from a fluid catalytic cracking (FCC) process, a methanol to olefins (MTO) process or both.
17 . The process of claim 1 further comprising: passing said carbon dioxide rich flue gas stream to a third stage separator (TSS) to separate catalyst fines in an underflow stream and provide a carbon dioxide rich flue gas stream with reduced catalyst fines in an overflow stream; passing said underflow stream to said decontamination reactor to form said reactor effluent stream comprising reactant salt; and generating electricity from said overflow stream in an expander; and passing said overflow stream to a heat recovery section.
18 . The process of claim 1 wherein the reactant salt comprises one or more of sodium sulphate (Na2SO4), sodium carbonate (Na2CO3) and sodium nitrate (NaNO3).
19 . A process for regenerating catalyst from a fluidized catalytic process comprising: providing an oxygen stream and a preheated carbon dioxide recycle stream; mixing said oxygen stream and said preheated carbon dioxide recycle stream to provide a carbon dioxide rich oxidation stream; separating said carbon dioxide rich oxidation stream into a first portion and a second portion; passing the first portion of said carbon dioxide rich oxidation stream to a regenerator unit to provide a carbon dioxide rich flue gas stream; passing the second portion of said carbon dioxide rich oxidation stream to heat recovery section to provide a partially cooled carbon dioxide rich flue gas stream and a steam stream; reacting one or more of a sulfur-containing compound, a nitrogen-containing compound, or both in said partially cooled carbon dioxide rich flue gas stream with a reactant in a decontamination reactor to form a reactor effluent stream comprising reactant salt; filtering the reactor effluent stream to remove the reactant salt and catalyst fines to produce a filtered reactor effluent stream; compressing said filtered reactor effluent stream to provide a compressed filtered reactor effluent stream; and recycling said compressed filtered reactor effluent stream to said regenerator unit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application No. 63/390,891, filed Jul. 20, 2022, and U.S. Provisional Application No. 63/407,151, filed Sep. 15, 2022, and U.S. Provisional Application No. 63/485,194, filed Feb. 15, 2023, which is incorporated herein in its entirety. FIELD The field is related to a process and apparatus for regenerating catalyst from a fluidized catalytic process. Particularly, the field relates to a process for regenerating catalyst from a fluidized catalytic process with a carbon dioxide (CO2) recycle stream. BACKGROUND Catalytic cracking can create a variety of products from larger hydrocarbons. Often, a feed of a heavier hydrocarbon, such as a vacuum gas oil, is provided to a catalytic cracking reactor, such as a fluid catalytic cracking reactor. Various products may be produced from such a system, including a gasoline product and/or light product such as propene and/or ethene. Fluid catalytic cracking (FCC) is a hydrocarbon conversion process accomplished by contacting hydrocarbons in a fluidized reaction zone with a catalyst composed of finely divided particulate material. The reaction in catalytic cracking, as opposed to hydrocracking, is carried out in the absence of substantial added hydrogen or the consumption of hydrogen. As the cracking reaction proceeds substantial amounts of highly carbonaceous material referred to as coke is deposited on the catalyst. A high temperature regeneration operation within a regenerator zone combusts coke from the catalyst. Coke-containing catalyst, referred to herein as coked catalyst, is continually removed from the reaction zone and replaced by essentially coke-free catalyst from the regeneration zone. Fluidization of the catalyst particles by various gaseous streams allows the transport of catalyst between the reaction zone and regeneration zone. Spent catalyst from the reaction zone can be completely or partially regenerated in the regeneration zone. A common objective of these configurations is maximizing product yield from the reactor while minimizing operating and equipment costs. Optimization of feedstock conversion ordinarily requires essentially complete removal of coke from the catalyst. This essentially complete removal of coke from catalyst is often referred to as complete regeneration. Complete regeneration produces a catalyst having less than 0.1 and preferably less than 0.05 wt-% coke. In order to obtain complete regeneration, the catalyst has to be in contact with oxygen at elevated temperature for sufficient residence time to permit thorough combustion. Conventional regenerators typically include a vessel having a coked catalyst inlet, a regenerated catalyst outlet and a combustion gas distributor for supplying air or other oxygen containing gas to the bed of catalyst that resides in the vessel. Cyclone separators remove catalyst entrained in the flue gas before the gas exits the regenerator. Alternative processes are also used for light olefins production. In one approach, hydrocarbon oxygenates and more specifically methanol or dimethyl ether are used as an alternative feedstock for producing light olefin products. Once the oxygenates are formed, the process includes catalytically converting the oxygenates, such as methanol, into the desired light olefin products in a methanol to olefin (MTO) process. In the MTO process, carbonaceous material, i.e., coke, is deposited on the catalyst as it moved through the reaction zones. The carbonaceous material is removed from the catalyst by oxidative regeneration in one or more regeneration zones wherein a moving bed of the catalyst particles withdrawn from the reaction zones is contacted with an oxygen-containing gas stream at sufficient temperature and oxygen concentration to allow the desired amount of the carbonaceous materials to be removed by combustion from the catalyst. In some cases, it is advantageous to only partially regenerate the catalyst, e.g., to remove from about 30 to 80 wt-% of the carbonaceous material. Flue gas formed by burning the coke in the regenerator is treated for removal of particulates and conversion of carbon monoxide (CO), after which the flue gas is normally discharged into the atmosphere. Further, incomplete combustion to carbon monoxide can result from poor fluidization or aeration of the coked catalyst in the regenerator or poor distribution of coked catalyst into the regenerator. Generally, the flue gas exiting the regenerator contains carbon monoxide, carbon dioxide, nitrogen and water, along with smaller amounts of other species. Flue gas treatment methods are effective, but the capital and operating costs are high. Conventional treatment of flue gas from FCC units and MTO units involve the use of wet gas scrubbing technology, such as a caustic scrubber, to remove sulfur compounds from the flue gas. In this process, the flue gas from the FCC regenerator is heat exchanged with boiler feed wa