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EP-4739753-A1 - METHOD AND APPARATUS FOR STRIPPING NOX, OXYGEN, CO, AND CO2 FROM FCC REGENERATED CATALYST FOR IMPROVING THE SAFETY AND RELIABILITY OF PRODUCT RECOVERY SECTION

EP4739753A1EP 4739753 A1EP4739753 A1EP 4739753A1EP-4739753-A1

Abstract

Processes for cracking hydrocarbons include contacting hydrocarbon feedstocks with conditioned cracking catalyst in a riser reactor to recover an effluent. The effluent is separated to recover a cracked hydrocarbon stream and a spent catalyst. The spent catalyst is contacted with steam, stripping residual hydrocarbons from the spent catalyst, and the stripped catalyst is fed to a catalyst regenerator and regenerated via combustion of coke contained in the spent catalyst, forming a regenerated catalyst and combustion products. The regenerated catalyst, containing entrained combustion products (e.g., NOx, SOx, and COx) including nitrogen from the regenerator, is fed to a catalyst standpipe hopper. The regenerated catalyst containing entrained combustion products is conditioned in the catalyst standpipe hopper by contacting the regenerated catalyst with steam to recover the conditioned catalyst and a vapor stream comprising steam and the combustion products. The conditioned catalyst, depleted of combustion products, is then fed to the riser reactor.

Inventors

  • GUNDALE, Mangesh, M.
  • BELWOOD, Ian
  • MARRI, Rama, Rao
  • ROY SOM, Manoj

Assignees

  • Lummus Technology LLC

Dates

Publication Date
20260513
Application Date
20240702

Claims (11)

  1. 1. A process for cracking hydrocarbons, the process comprising: contacting a hydrocarbon feedstock with a conditioned cracking catalyst in a riser reactor to recover a riser effluent comprising spent catalyst and cracked hydrocarbons; separating the riser effluent to recover a cracked hydrocarbon stream and a spent catalyst; contacting, in a stripper, the spent catalyst with steam to strip residual hydrocarbons from the spent catalyst, forming a stripped catalyst; feeding the stripped catalyst to a catalyst regenerator; regenerating, in the catalyst regenerator, the stripped catalyst via combustion of coke contained in the stripped catalyst to form a regenerated catalyst containing entrained combustion products; feeding the regenerated catalyst containing entrained combustion products from the catalyst regenerator to a regenerated catalyst standpipe hopper, wherein the entrained combustion products include nitrogen oxides, sulfur oxides, and carbon oxides including nitrogen; conditioning the regenerated catalyst in the regenerated catalyst standpipe hopper, wherein the conditioning comprises contacting the regenerated catalyst containing entrained combustion products with steam to recover a conditioned catalyst and a vapor stream comprising steam and combustion products; feeding the conditioned catalyst to the riser reactor; feeding the vapor stream to the catalyst regenerator; and recovering the combustion products and the vapor stream as a flue gas from the catalyst regenerator.
  2. 2. The process of claim 1, wherein the regenerated catalyst standpipe hopper contains internals configured to facilitate countercurrent contact of the regenerated catalyst containing entrained combustion products including nitrogen with the steam or other industrial inert gases.
  3. 3. The process of claim 2, wherein the regenerated catalyst standpipe hopper contains MODGRID internals available from Lummus Technology LLC.
  4. 4. The process of any one of the above claims, wherein the stripper contains internals configured to facilitate countercurrent contact of the spent catalyst with the steam.
  5. 5. The process of any one of the above claims, wherein the feeding of the conditioned catalyst to the riser reactor comprises feeding the conditioned catalyst from the regenerated catalyst standpipe hopper to the riser reactor via a regenerated catalyst standpipe, the process further comprising fluffing the conditioned catalyst within the regenerated catalyst standpipe with air or steam.
  6. 6. The process of any one of the above claims, wherein the feeding of the stripped catalyst from the stripper to the catalyst regenerator comprises feeding stripped catalyst from the stripper to the catalyst regenerator via a spent catalyst standpipe, the process further comprising fluffing the stripped catalyst within the spent catalyst standpipe with steam.
  7. 7. A system for cracking hydrocarbons, the system comprising: a riser reactor for contacting a hydrocarbon feedstock with a conditioned cracking catalyst to recover a riser effluent comprising spent catalyst and cracked hydrocarbons; a separation system for separating the riser effluent to recover a cracked hydrocarbon stream and a spent catalyst; a stripper for contacting the spent catalyst with steam to strip residual hydrocarbons from the spent catalyst producing a stripped catalyst; a catalyst regenerator for regenerating the stripped catalyst via combustion of coke contained in the stripped catalyst to form a regenerated catalyst and combustion products; a flow line for feeding regenerated catalyst containing entrained combustion products from the catalyst regenerator to a regenerated catalyst standpipe hopper, wherein the entrained combustion products include nitrogen oxides, sulfur oxides, and carbon oxides including nitrogen; a conditioning system within the regenerated catalyst standpipe hopper for contacting the regenerated catalyst containing entrained combustion products with steam to recover a conditioned catalyst and a vapor stream comprising steam and combustion products; a conditioned catalyst standpipe for feeding the conditioned catalyst to the riser reactor; a flow line for feeding the vapor stream to the catalyst regenerator; and a flow line for collectively recovering the combustion products and the vapor stream as a flue gas from the catalyst regenerator.
  8. 8. The system of claim 7, wherein the conditioning system in the regenerated catalyst standpipe hopper comprises internals configured to facilitate countercurrent contact of the regenerated catalyst containing entrained combustion products with the steam or other industrial inert gases.
  9. 9. The system of any one of claims 7-8, wherein the stripper contains internals configured to facilitate countercurrent contact of the spent catalyst with the steam.
  10. 10. The system of any one of claims 7-9, further comprising a spent catalyst standpipe for feeding stripped catalyst from the stripper to the catalyst regenerator, and further comprising a flow line for introducing steam into the spent catalyst standpipe.
  11. 11. The system of any one of claims 7-10, further comprising a flow line for introducing air into the conditioned catalyst standpipe.

Description

METHOD AND APPARATUS FOR STRIPPING NOX, OXYGEN, NITROGEN, CO, AND CO2 FROM FCC REGENERATED CATALYST FOR IMPROVING THE PEFORMANCE, SAFETY, AND RELIABILITY OF PRODUCT RECOVERY SECTION FIELD OF THE DISCLOSURE [0001] Embodiments of the present disclosure generally relate to processes and systems to reduce flue gas components such as nitrogen oxides, sulfur oxides, oxygen, carbon monoxide, and carbon dioxide including nitrogen from FCC regenerated catalysts flowing from a catalyst regenerator to a riser-reactor. BACKGROUND [0002] In recent years, the changing dynamics of the market have prompted refineries to explore new opportunities in petrochemical production from crude oil, shifting their focus beyond fuel production as fuel demand is depleting. Among the key building blocks for the petrochemical industry, ethylene and propylene hold significant importance. Due to the depleting demand of fuels and increasing demand of petrochemicals, refiners are being compelled to find the options to maximize petrochemicals from processing a variety of crude oils. Ethylene and propylene are expected to be in high demand, as they are the primary feed stock for the petrochemical/polymer industries. [0003] It has been proposed to directly process crude oils, or select boiling range fractions therefrom, without significant upstream processing, such as in a fluid catalytic cracking unit. Unfortunately, limiting upstream processing may result in a greater concentration of various impurities, such as sulfur and nitrogen, being introduced into the fluid catalytic cracking unit and associated downstream equipment. SUMMARY OF THE CLAIMED EMBODIMENTS [0004] In one aspect, embodiments disclosed herein relate to a method and apparatus for reducing the flue gas components, such as sulfur oxides, carbon oxides, nitrogen oxides, and oxygen, within a fluidized catalytic cracking (FCC) unit. The reduction of these flue gas components provides for safe and reliable operation of the downstream product recovery section. In particular, the NOx contributes to gum formation, which maybe a safety hazard in the cold box section. This is achieved with the addition of internals in the traditional Regenerated Catalyst Standpipe Hopper (RCSP Hopper) which will enable the efficient stripping of these harmful components of flue gas to the FCC reactor and product recovery section. The preferred stripping medium may be steam or other industrial inert gases such as nitrogen as compared to conventional fluffing media (plant air or blower air). [0005] In another aspect, embodiments disclosed herein relate to a reduction in size of oxygen converter and catalyst due to reduction in flue gas components. This will also reduce the loss of ethylene product across the oxygen converter. [0006] In another aspect, embodiments disclosed herein relate to a to reduction of other flue gas components like sulfur oxides, carbon monoxides, carbon dioxides etc.; which are the combustion products of the feed impurities landing into FCC regenerator with same claimed scheme. This will help in reducing the size of down product recovery section and will also reduce the utility consumption. [0007] Embodiments herein thus relate to a process for cracking hydrocarbons. The process includes contacting a hydrocarbon feedstock with a conditioned cracking catalyst in a riser reactor to recover a riser effluent comprising spent catalyst and cracked hydrocarbons. The riser effluent is separated to recover a cracked hydrocarbon stream and a spent catalyst. The spent catalyst is then contacted, in a stripper, with steam to strip residual hydrocarbons from the spent catalyst, and the spent catalyst is fed from the stripper to a catalyst regenerator where the spent catalyst is regenerated via combustion of coke contained in the spent catalyst to form a regenerated catalyst and combustion products. The regenerated catalyst, containing entrained combustion products from the catalyst regenerator, is then fed to a catalyst standpipe hopper. The entrained combustion products include, for example, nitrogen oxides, sulfur oxides, and carbon oxides. The regenerated catalyst is conditioned, in the catalyst standpipe hopper, by contacting the regenerated catalyst containing entrained combustion products with steam to recover the conditioned catalyst and a vapor stream comprising steam and the combustion products. The conditioned catalyst is then fed to the riser reactor. The vapor stream is fed to the catalyst regenerator, the process further recovering the combustion products and the vapor stream as a flue gas from the catalyst regenerator. [0008] In some embodiments, the catalyst standpipe hopper contains internals configured to facilitate countercurrent contact of the regenerated catalyst containing entrained combustion products with the steam. [0009] In various embodiments, the stripper contains internals configured to facilitate countercurrent contact of the spent catalyst with the steam. [0010]