Solvent System for In Situ Fixed Bed Reactor Catalyst Cleaning
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Solution Overview
Problem
Current methods for removing coke deposits and reducing hydrocarbon vapors to below the lower explosive limit (LEL) in industrial equipment are inefficient, often requiring extended downtimes and risking equipment damage, as they either fail to effectively lower vapor concentrations or introduce catalyst poisons during the regeneration process.
Innovation Solution
A method involving a hot hydrogen stream combined with a fatty acid methyl ester and an oxygenated solvent is circulated through the equipment to dissolve and disaggregate deposits, followed by a nitrogen purge to ensure safe vessel entry, allowing for quicker and safer removal of contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional steaming or hydrogen sweep methods are used to remove coke deposits, then deposits are removed to some extent, but the process takes extended time and may compact coke into harder deposits
Solution Approach 1:
The patent introduces a solvent composition with specific chemical properties (fatty acid methyl ester and oxygenated solvent in controlled ratios) that changes the chemical environment for deposit removal. This chemical parameter change enables faster and more effective coke dissolution compared to traditional thermal methods, resolving the contradiction between removal efficiency and time loss
Solution Approach 2:
The solvent composition acts as an intermediary substance between the hydrogen stream and the coke deposits. It facilitates the removal process by chemically interacting with and dissolving the deposits, enabling faster cleanup without the need for extended thermal treatment that would increase downtime
2Strength
If high temperature steam is used to remove deposits, then deposits are broken up, but the temperature may compact soft coke into hard coke creating tougher deposits
Solution Approach 1:
The patent changes the temperature parameter by using a cooler solvent-based chemical cleaning approach instead of high-temperature steam. The solvent composition effectively dissolves deposits at lower temperatures, preventing the thermal compaction that would otherwise harden soft coke into tougher deposits
Solution Approach 2:
The patent replaces the mechanical/thermal breakdown mechanism (steam heating and physical force) with a chemical dissolution mechanism. The solvent composition chemically dissolves the coke deposits, achieving effective removal without the mechanical compaction effects that create harder, more difficult-to-remove deposits
3Productivity
If conventional cleaning methods are used, then deposits are removed, but catalyst poisons may be introduced during the regeneration process
Solution Approach 1:
The patent uses nitrogen as an inert atmosphere to displace oxygen and prevent unwanted chemical reactions during the cleaning process. This inert environment protects the catalyst from oxidation and contamination, ensuring that regeneration occurs without introducing catalyst poisons while maintaining catalyst activity
Solution Approach 2:
The solvent composition serves as a controlled intermediary that removes deposits without introducing harmful substances. By using specifically selected solvents (fatty acid methyl ester and oxygenated solvent) in controlled ratios, the process achieves effective cleaning while avoiding the introduction of catalyst poisons that would occur with conventional cleaning agents
4Ease of operation
If equipment is opened for catalyst removal, then maintenance can be performed, but residual hydrocarbon vapors above LEL create fire hazards
Solution Approach 1:
The patent uses nitrogen to create an inert atmosphere that displaces oxygen and reduces hydrocarbon vapor concentrations below the lower explosive limit (LEL). This ensures that when equipment is opened for maintenance, the atmosphere is non-flammable and safe for personnel entry, eliminating the fire hazard associated with residual hydrocarbon vapors
Solution Approach 2:
The patent converts the potentially harmful residual hydrocarbon vapors into a beneficial situation by using nitrogen displacement to reduce vapor concentrations below LEL. The nitrogen acts as a protective medium that transforms the hazardous vapor-rich environment into a safe, inert atmosphere suitable for maintenance operations
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 approach effectively reduces hydrocarbon vapor concentrations below the LEL, enabling safe and efficient de-inventorying of catalysts and equipment maintenance, while minimizing downtime and preventing equipment damage.
Implementation Method 1
a hot hydrogen stream comprising hydrogen, a fatty acid methyl ester, and an oxygenated solvent are circulated through equipment. The hot hydrogen stream may dissolve and disaggregate at least a portion of deposits collected in the equipment.
Implementation Method 2
The hot hydrogen stream may dissolve and disaggregate at least a portion of deposits collected in the equipment... effectively reduces hydrocarbon vapor concentrations below the LEL
Implementation Method 3
followed by a nitrogen purge to ensure safe vessel entry
Data Source
AI summary
A method of equipment decontamination may include: introducing a cleaning stream comprising hydrogen and a solvent comprising a fatty acid methyl ester and an oxygenated solvent into the equipment; and introducing a stream comprising nitrogen into the equipment, wherein the equipment comprises deposits and other contaminants.