Pre-reform Catalyst Activity Maintenance via Methanol Injection
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Solution Overview
Problem
Nickel-based pre-reform catalysts in hydrogen production units deactivate rapidly due to oxidation or coke deposition when hydrogen is absent in the feed, leading to unscheduled shutdowns and increased operational costs.
Innovation Solution
Introducing a catalyst activity maintenance fluid, such as methanol, formaldehyde, or formic acid, into the pre-reform reactor with a steam-to-fluid ratio between 200 and 40 mol/mol, and stopping its feed when hydrogen returns, to maintain catalyst activity and prevent deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hydrogen is absent in the feed, then operational costs are reduced, but the pre-reform catalyst deactivates rapidly due to oxidation or coke deposition
Solution Approach 1:
The patent introduces a maintenance fluid (methanol, formaldehyde, or formic acid) into the reactor before complete hydrogen depletion occurs. This preliminary action maintains the catalyst in a reduced state and prevents oxidation or coke deposition that would otherwise occur during hydrogen absence, thereby avoiding catalyst deactivation while allowing operational cost reductions
Solution Approach 2:
The maintenance fluid acts as an intermediary substance that mediates between the catalyst and the hydrogen-depleted environment. It provides the necessary reducing atmosphere and prevents harmful interactions between the catalyst and oxygen or hydrocarbons during periods when hydrogen is absent, thus preserving catalyst activity without requiring continuous hydrogen supply
2Reliability
If the pre-reform catalyst is maintained active by continuous hydrogen supply, then catalyst activity is preserved, but operational costs increase and unscheduled shutdowns occur
Solution Approach 1:
The patent implements periodic introduction of maintenance fluid during periods when hydrogen is absent, rather than requiring continuous hydrogen supply. This periodic action maintains catalyst activity through controlled intervals of fluid injection, reducing the overall hydrogen consumption and operational costs while preventing catalyst deactivation
Solution Approach 2:
The maintenance fluid (methanol, formaldehyde, or formic acid) serves as a temporary, consumable substance that provides the necessary protective function during hydrogen absence. This disposable approach is more economical than continuous hydrogen supply, as these fluids can be introduced intermittently to maintain catalyst activity without requiring ongoing expensive hydrogen input
3Reliability
If the pre-reform reactor is shut down to protect the catalyst, then catalyst deactivation is prevented, but hydrogen production stops and operational time is lost
Solution Approach 1:
The maintenance fluid is introduced in advance before catalyst deactivation can occur during hydrogen absence. This preliminary protective action allows the reactor to remain operational and continue hydrogen production without shutdown, as the catalyst is protected in-situ rather than requiring reactor cessation
Solution Approach 2:
The maintenance fluid enables the catalyst to protect itself during hydrogen absence by creating a protective reducing atmosphere around the catalyst particles. This self-service mechanism allows the catalyst to withstand hydrogen-depleted conditions without external intervention or shutdown, maintaining both catalyst protection and continuous hydrogen production
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method extends the operational time of hydrogen production units, reduces shutdowns, and minimizes the need for catalyst replacement, thereby reducing costs and safety risks.
Implementation Method 1
introducing into the feed of the pre-reform reactor a catalyst activity maintenance fluid, in which the fluid is selected from methanol, formaldehyde, formic acid or mixtures thereof
Implementation Method 2
The process can utilize hydrocarbons chosen from natural gas, liquefied petroleum gas (LPG), refinery gases and naphtha, although the broader use in industry is in the production of hydrogen from natural gas. The main reactions that occur in the steam reforming process are the so-called reforming reactions
Implementation Method 3
avoid the deactivation of pre-reform catalysts by oxidation or by deposition of coke
Implementation Method 4
maintaining the activity of pre-reform catalysts, having nickel as the active phase
Implementation Method 5
CnHm+nH2O=nCO+(1⁄2m+n)H2 (endothermic reaction) Reaction 1
Implementation Method 6
CO+H2O=CO2+H2 (exothermic, −41.2 KJ/mol) Reaction 3
Data Source
AI summary
The present invention addresses to a method of maintaining the activity of pre-reform catalysts in hydrogen production units, in order to avoid deactivation by oxidation or coke deposition of pre-reform catalysts in the absence of hydrogen in the feed consisting of hydrocarbon and water vapor.