Catalyst Regeneration via High-Pressure Oxygen Purging
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Solution Overview
Problem
Conventional catalytic reforming processes face inefficiencies in catalyst regeneration due to high temperatures and pressures, lengthy downtime, and the formation of corrosive by-products like HCl, which damage equipment and prolong regeneration times.
Innovation Solution
A process involving circulating oxygen-containing gas streams at moderate pressures (50 psig to 400 psig) and temperatures (700° to 1000° F) to remove carbon deposits, followed by inert gas purging to reduce oxygen content, and subsequent hydrogen introduction to maintain catalyst activity, all while using existing reforming process equipment to minimize downtime and reduce exposure to corrosive compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional low-pressure purging is used to remove oxygen from the catalyst bed, then equipment is protected from high-pressure stress, but regeneration time increases significantly due to additional cooling and heating cycles
Solution Approach 1:
The patent changes the pressure parameter from conventional low-pressure purging to high-pressure purging (maintaining reaction pressure during oxygen removal). This allows the oxygen purging step to occur without requiring subsequent pressure changes, eliminating the need for cooling and re-heating cycles, thus reducing regeneration time while maintaining equipment integrity through controlled pressure management
Solution Approach 2:
The patent enables continuous operation by performing oxygen purging at the same pressure as the reforming reaction. This eliminates idle time between steps and allows the system to maintain continuous useful action without interruption for pressure adjustments, thereby reducing overall regeneration time
2Reliability
If halogen compounds are used during regeneration for platinum redispersion, then catalyst activity is restored, but corrosive by-products damage equipment and increase maintenance requirements
Solution Approach 1:
The patent converts the harmful effect of halogen compounds by performing regeneration at high temperature and pressure conditions where halogen-containing compounds are minimized or eliminated. The harsh conditions that would normally cause corrosion are instead used to achieve complete coke removal and catalyst regeneration without halogen additives, thereby eliminating corrosion while maintaining catalyst activity
Solution Approach 2:
The patent changes the temperature and pressure parameters to elevated levels during regeneration, which allows for effective coke removal and catalyst regeneration without requiring halogen compounds. This parameter change eliminates the source of corrosive by-products while achieving the desired catalyst restoration
3Reliability
If multiple temperature cycles are used in conventional regeneration, then oxygen is effectively removed from the catalyst bed, but energy consumption increases and equipment undergoes thermal stress
Solution Approach 1:
The patent maintains constant high temperature and pressure throughout the oxygen removal process rather than using multiple temperature cycles. This single-stage approach at elevated parameters achieves effective oxygen removal without the energy-intensive heating and cooling cycles, reducing energy consumption and thermal stress on equipment
Solution Approach 2:
The patent replaces periodic temperature cycling with continuous operation at constant elevated temperature and pressure. This eliminates the repeated thermal cycling that causes energy loss and thermal stress, while achieving the same oxygen removal objective through sustained harsh conditions
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 reduces regeneration time, minimizes equipment damage, and operates more economically by maintaining higher temperatures and pressures, allowing for faster catalyst rejuvenation and reduction, thus enhancing operational efficiency and reducing exposure to corrosive substances.
Implementation Method 1
circulating a first oxygen-containing gas stream from a gas compressor to a catalyst bed in a reforming reaction zone in order to remove at least a portion of the carbonaceous deposits on the reforming catalyst
Implementation Method 2
an inert gas stream is passed from the gas compressor, at a pressure in the range of about 5 psig to about 300 psig and at a temperature in the range of about 700° to about 1000° F., through the reforming catalyst bed to purge a substantial portion of the oxygen contained therein
Implementation Method 3
The reforming catalyst bed is then pressured with hydrogen gas at a rate sufficient to maintain a pressure in the range of about 100 psig to about 325 psig and at a temperature of above about 700° F.
Data Source
AI summary
This invention is directed to a process for regenerating a deactivated reforming catalyst by circulating a first oxygen-containing gas stream from a gas compressor to a catalyst bed in a reforming reaction zone in order to remove at least a portion of the carbonaceous deposits on the reforming catalyst. Then, a second oxygen-containing gas stream is further circulated from the gas compressor to the reforming catalyst bed, for oxidizing the reforming catalyst, and an inert gas stream is passed from the gas compressor through the reforming catalyst bed to purge a substantial portion of the oxygen contained therein for a time sufficient to reduce the oxygen content of an exiting purge gas stream to less than about 2% by volume oxygen.