Membrane Wall Gasification for Spent Catalyst Recovery
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Solution Overview
Problem
The existing methods for disposing of spent coked catalysts in petroleum refining are costly and environmentally challenging, with partial oxidation gasification processes facing refractory lining degradation and high capital costs, while also complicating the recovery of active metal compounds from slag due to contaminant metals.
Innovation Solution
A process involving grinding spent coked catalysts to produce a flowable particulate feed, which is then gasified in a membrane wall reactor to produce synthesis gas, followed by leaching the slag to recover active metals, with the remaining catalyst support material suitable for cement production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spent catalysts are disposed of using conventional methods (landfill, incineration), then disposal is achieved, but high costs and environmental pollution occur
Solution Approach 1:
The patent converts the harmful waste problem into a beneficial resource recovery process. Spent catalysts containing valuable metals (Ni, Co, Mo, W, Pt, Pd) are gasified to produce syngas (a valuable chemical feedstock) and metal-containing slag (a recoverable resource). This transforms environmental pollution into economic value through simultaneous energy recovery and metal recycling
Solution Approach 2:
The patent implements a comprehensive recovery system that captures both energy and materials from spent catalysts. The gasification process recovers syngas from the carbonaceous content while the subsequent leaching process recovers precious metals from the slag. This dual recovery approach eliminates the need for conventional disposal methods entirely
2Productivity
If partial oxidation gasification is used to dispose of spent catalysts, then syngas production is achieved, but refractory lining degradation occurs at high temperatures
Solution Approach 1:
The patent employs a membrane wall reactor design that replaces conventional refractory linings with a thin metallic membrane structure. This membrane wall provides thermal barrier protection while being more resistant to degradation at gasification temperatures (800-1500°C), thereby maintaining reactor reliability during continuous syngas production
Solution Approach 2:
The membrane wall structure represents a composite engineering solution combining metallic materials with thermal barrier properties. This composite construction provides both mechanical strength and thermal protection, solving the refractory degradation problem while enabling sustained high-temperature gasification operations
3Reliability
If membrane wall reactor is used for gasification, then refractory degradation is reduced, but capital costs increase
Solution Approach 1:
The patent changes the operational parameters of the gasification process to optimize the membrane wall performance. By controlling temperature profiles, residence times, and gas composition within specific ranges, the membrane wall durability is maximized while capital costs are justified through extended reactor life and reduced maintenance
4Duration of action of moving object
If spent catalysts are regenerated instead of replaced, then catalyst life is extended, but catalytic activity diminishes with each regeneration
Solution Approach 1:
Rather than attempting to restore catalyst activity through regeneration, the patent discards the deactivated catalyst and recovers the valuable metals for reuse. This approach recognizes that regeneration cannot fully restore activity and instead creates a circular economy where metals are continuously recycled into fresh catalysts
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 integrated process effectively disposes of spent catalysts, reduces refractory lining degradation, and recovers valuable active metals, offering a cost-effective and environmentally acceptable solution for catalyst disposal and metal recovery.
Implementation Method 1
the partial oxidation of the feedstream containing the spent coked catalyst in a membrane wall gasification reactor to produce hydrogen and carbon monoxide, i.e., synthesis gas
Implementation Method 2
contacting the prepared slag material with an aqueous leaching solution to solubilize one or more active phase metals in the aqueous leaching solution
Data Source
AI summary
An integrated refinery process for the disposal of metal-containing spent coked catalyst from hydrotreating and/or hydrocracking unit operations includes introducing the spent coked catalyst into a membrane wall gasification reactor in the form of flowable particles along with predetermined amounts of oxygen and steam based upon an analysis of the hydrocarbon content of the coke, and optionally, a liquid hydrocarbon; gasifying the feed to produce synthesis gas and a slag material; recovering and subjecting the slag material to further processes in preparation for a leaching step to solubilize and form one or more active phase metal compounds that are recovered from the leaching solution, either separately by sequential processing, or together. The recovered active metal compounds can be used, e.g., in preparing fresh catalyst for use in the refinery's hydroprocessing units.