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Method of Operating a Prereformer during a Planned or Unplanned Shutdown

IP.com Disclosure Number: IPCOM000244771D
Publication Date: 2016-Jan-12
Document File: 10 page(s) / 69K

Publishing Venue

The IP.com Prior Art Database

Abstract

A method of operating a prereformer during an unplanned shutdown includes evacuating the prereformer of any residual gas in the prereformer responsive to detection of a condition that triggers a control response that stops the introduction of the prereformer feed gas mixture and purging the prereformer with a purge 5 gas. The purge gas may be an oxygen-free nitrogen-containing gas optionally comprising hydrogen.

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TITLE:

Method of Operating a Prereformer during a Planned or Unplanned Shutdown

ABSTRACT


[0001] A method of operating a prereformer during an unplanned shutdown includes evacuating the prereformer of any residual gas in the prereformer responsive to detection of a condition that triggers a control response that stops the introduction of the prereformer feed gas mixture and purging the prereformer with a purge gas. The purge

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gas may be an oxygen-free nitrogen-containing gas optionally comprising hydrogen.

BACKGROUND


[0002] Prereformers are used in the hydrogen production industry to facilitate processing of hydrocarbon feedstocks containing higher hydrocarbons (e.g. C2+

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hydrocarbons) and/or to improve the energy efficiency of the hydrogen production process.


[0003] Prereformers use a specialized prereforming catalyst that typically has a higher nickel content and higher surface area compared to reforming catalyst used in conventional steam methane reformers. During operation, prereforming catalyst is in a

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reduced state. Care must be taken to prevent the prereforming catalyst from becoming oxidized, otherwise the prereforming catalyst will become inactive and must be replaced. In case the prereforming catalyst becomes oxidized, it cannot be regenerated to recover its activity. Instead, it must be replaced, resulting in increased costs.


[0004] Hydrogen production plants monitor various conditions that trigger a shutdown 20

of the process in order to ensure that the process operates within safety limits.


[0005] Prereforming catalyst is at risk of becoming damaged, oxidized, and deactivated during unplanned shutdowns. Steam introduced as a reactant for reforming the hydrocarbon feedstock can condense, which could damage the prereforming catalyst pellets. An oxidant such as air might enter the prereformer and oxidize the prereforming

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catalyst.

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[0006] Industry desires to prevent damage, oxidation, and deactivation of prereforming catalyst.


[0007] The present disclosure is a method of operating a prereformer during a planned and/or an unplanned shutdown in order to prevent damage, oxidation, and deactivation of prereforming catalyst contained therein.

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DETAILED DESCRIPTION


[0008] The present disclosure relates to a method of operating a prereformer during an unplanned shutdown. The method is described with refererence to the sole figure

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showing a process flow diagram of a portion of a hydrogen production facility.


[0009] The method relates to a steam-hydrocarbon reforming process utilizing catalytic steam reforming. Catalytic steam reforming, also called steam methane reforming (SMR) or steam reforming, is defined as any process used to convert reformer feedstock to synthesis gas by reaction with steam over a catalyst. Synthesis gas, commonly called 15

syngas, is any mixture comprising hydrogen and carbon monoxide. The reforming reaction is an endothermic reaction and may be described generally as CnHm...