Low-Acidity Zeotype Catalysts for Fischer-Tropsch Wax Hydrocracking
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Solution Overview
Problem
Existing catalysts for hydrocracking Fischer-Tropsch wax are inefficient in converting high-boiling paraffinic waxes into distillate and naphtha boiling range products, often requiring high temperatures that lead to thermal cracking and reduced yields.
Innovation Solution
Employing noble metal catalysts supported on low acidity supports with 3-dimensional zeotype frameworks, such as USY, zeolite Beta, and MCM-68, which enhance cracking activity and yield while minimizing thermal cracking by operating at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking catalysts are used to convert Fischer-Tropsch wax into distillate boiling range products, then cracking activity is achieved, but thermal cracking occurs at high temperatures leading to reduced yields
Solution Approach 1:
The patent changes the acidity parameter of the catalyst support by using low acidity supports (such as silica-alumina with specific Si/Al ratios, or alumina with controlled surface area and pore volume) to reduce thermal cracking while maintaining adequate cracking activity. This parameter change allows operating at lower temperatures to achieve the same conversion, thereby reducing harmful thermal cracking effects.
Solution Approach 2:
The patent employs composite catalyst systems combining metal functions (for hydrocracking) with support materials having specific acidity characteristics. The composite structure of metal particles dispersed on low-acidity supports creates a synergistic effect that enhances cracking activity while suppressing thermal cracking, resolving the contradiction between productivity and harmful effects.
2Productivity
If high temperatures are used to achieve adequate cracking activity, then conversion of waxy feedstock is improved, but thermal cracking increases reducing product yield
Solution Approach 1:
The patent modifies the acidity parameter of the catalyst support to operate at lower temperatures. By using supports with controlled acidity (such as silica-alumina with Si/Al ratios of 5-50, or alumina with specific surface areas), the catalyst maintains high cracking activity at reduced temperatures, preventing the formation of thermal cracking products while achieving adequate conversion.
Solution Approach 2:
The patent replaces thermal energy (heat) as the primary driving force for cracking with catalytic activity. By using low-acidity supports that provide active sites for cracking reactions, the process substitutes chemical catalysis for thermal cracking, enabling conversion at lower temperatures and avoiding the harmful effects of high-temperature thermal cracking.
3Productivity
If catalyst acidity is increased to enhance cracking activity, then conversion efficiency improves, but thermal cracking and reduced selectivity occur
Solution Approach 1:
The patent optimizes the acidity parameter of the support by controlling Si/Al ratios, surface area, and pore volume to achieve an optimal balance. Low-acidity supports provide sufficient cracking activity through controlled acid site density, while preventing excessive cracking that would reduce selectivity to desired distillate products. This parameter optimization resolves the contradiction between cracking activity and selectivity.
Solution Approach 2:
The patent creates localized active sites on the support surface with specific acidity characteristics. By controlling the distribution and density of acid sites through support preparation methods, the catalyst provides high cracking activity at specific locations while maintaining overall low acidity, thereby achieving good selectivity to distillate products while maintaining cracking efficiency.
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
Achieves higher yields of distillate and naphtha boiling range products with reduced thermal cracking, improving the efficiency and effectiveness of the hydrocracking process.
Implementation Method 1
noble metal catalysts supported on low acidity supports with 3-dimensional zeotype frameworks, such as USY, zeolite Beta, and MCM-68, which enhance cracking activity
Implementation Method 2
hydrocracking to form lighter molecules
Implementation Method 3
3-dimensional zeotype frameworks, such as USY, zeolite Beta, and MCM-68
Implementation Method 4
3-dimensional zeotype frameworks with specific pore structures
Data Source
AI summary
Catalysts and corresponding methods are provided for conversion of Fischer-Tropsch wax to distillate boiling range products. The catalysts can correspond to noble metal catalysts supported on a support that includes a 3-dimensional zeotype and a substantially non-acidic or low acidity oxide binder. It has been discovered that using a substantially non-acidic or low acidity binder allows for improved yield of distillate boiling range products when cracking Fischer-Tropsch wax. It has further been discovered that by using a support including a 3-dimensional zeotype, the temperature for achieving a target level of conversion during hydrocracking can be reduced or minimized