Hydrocracking Catalyst Life via Periodic Rate Switching
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Solution Overview
Problem
The existing methods for producing hydrocarbon oil using Fischer-Tropsch synthesis reactions face challenges in maintaining catalyst efficiency over time, leading to reduced yields and shorter catalyst lifespan due to catalyst degradation, especially when switching to light paraffin hydrocarbons to recover catalyst activity.
Innovation Solution
A method involving continuous hydrocracking of a wax fraction containing 70% or more straight-chain hydrocarbons with a boiling point above 360°C, alternating between high and low cracking rates to extend catalyst life and maintain efficiency, where the cracking rate is adjusted periodically to optimize hydrocracking product yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cracking rate is constantly maintained by raising reaction temperature over time, then the middle distillate yield is maintained, but the catalyst degradation accelerates and continuous operation time is reduced
Solution Approach 1:
The patent implements periodic switching between high cracking rate operation (for productivity) and low cracking rate operation (for catalyst protection). The operation alternates between these two states, allowing the catalyst to recover during low-rate periods while maintaining overall production efficiency. This periodic action resolves the contradiction by not constantly maintaining high cracking rate, thus reducing cumulative catalyst degradation.
Solution Approach 2:
The patent dynamically changes the cracking rate parameter over time, switching between high and low rates based on operational needs and catalyst state. This parameter change allows optimization of both productivity (when high rate is used) and catalyst lifespan (when low rate is used), resolving the contradiction between maintaining yield and extending continuous operation time.
2Reliability
If the raw material is switched to light paraffin hydrocarbons to recover catalyst activity, then the catalyst activity is restored, but the hydrocracking efficiency of wax fraction is reduced
Solution Approach 1:
Instead of permanently switching to light paraffin hydrocarbons, the patent uses periodic switching between high and low cracking rates during wax fraction hydrocracking. This allows catalyst activity recovery during low-rate periods without permanently reducing hydrocracking efficiency, as the system returns to high-rate operation for productive hydrocracking.
Solution Approach 2:
The patent maintains continuous hydrocracking of wax fraction by alternating between high and low rates, ensuring that the useful action of hydrocracking never stops. This avoids the interruption and efficiency loss associated with switching to light paraffin hydrocarbons, while still allowing catalyst recovery during low-rate periods.
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 suppresses catalyst degradation, extends continuous operation time, and improves hydrocarbon oil production efficiency without reducing the hydrocracking efficiency of the wax fraction.
Implementation Method 1
hydrocracking a wax to be processed in a wax fraction hydrocracking reactor packed with a hydrocracking catalyst
Implementation Method 2
separated into gas and liquid in a gas liquid separation apparatus. Then, the liquid component thus obtained (hydrocarbon oil) is sent to a fractionator
Data Source
AI summary
The present invention provides a method for producing a hydrocarbon oil, including performing a hydrocracking by continuously feeding, to a hydrocracking reactor containing a hydrocracking catalyst, a wax to be processed including: a raw wax containing 70% by mass or more of straight-chain hydrocarbons with a boiling point of higher than 360° C; and an uncracked wax containing 70% by mass or more of straight-chain hydrocarbons with a boiling point of higher than 360° C, which uncracked wax is separated from a hydrocracking product discharged from the reactor, to thereby yield a hydrocarbon oil including hydrocarbons with a boiling point of 360° C or lower.