Amorphous Silica-Alumina Catalyst for Low-Temperature Wax Hydrocracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catalysts for hydrocracking Fischer-Tropsch wax are inefficient in converting high-boiling point paraffins into distillate boiling range products, leading to substantial formation of unwanted naphtha and thermal cracking at high temperatures.
Innovation Solution
A noble metal catalyst supported on an amorphous silica-alumina support, formed via an extrusion process with nitric acid and methylcellulose, provides a beneficial combination of surface area, pore volume, and acidity, allowing high yields of distillate products at reduced temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking catalysts are used to convert Fischer-Tropsch wax, then some distillate products are formed, but substantial amounts of naphtha are formed and thermal cracking occurs at high temperatures
Solution Approach 1:
The patent changes the physical and chemical parameters of the catalyst support by creating an amorphous silica-alumina structure with specific surface area (360-500 m²/g) and pore volume (0.55-0.90 cm³/g), along with controlled acidity, to achieve high distillate yields at lower operating temperatures (300-400°C) that prevent thermal cracking and excessive naphtha formation
Solution Approach 2:
The patent uses a composite catalyst system combining noble metals (0.1-3.0 wt% Group 8-10) with amorphous silica-alumina support, creating a material that integrates the high activity of noble metals with the acidic properties of silica-alumina to achieve selective hydrocracking without thermal cracking
2Productivity
If high operating temperatures are used to increase conversion, then conversion increases, but thermal cracking increases and distillate selectivity decreases
Solution Approach 1:
The patent changes the operating temperature parameter to 300-400°C, which is lower than conventional processes, while maintaining high conversion (20 wt% or more) through the enhanced catalyst activity provided by the noble metal-amorphous silica-alumina system, thereby avoiding thermal cracking that occurs at higher temperatures
3Productivity
If existing catalysts are used, then hydrocracking occurs, but catalyst activity is insufficient and high temperatures are required
Solution Approach 1:
The patent combines noble metals (0.1-3.0 wt% of Group 8-10 metals such as Pt, Pd, Rh, Ir) with amorphous silica-alumina support to create a composite catalyst with high hydrocracking activity that operates at lower temperatures (300-400°C) while achieving 20 wt% or more conversion relative to 371°C
Solution Approach 2:
The patent optimizes the catalyst support parameters including surface area (360-500 m²/g), pore volume (0.55-0.90 cm³/g), and acidity to enhance the interaction with noble metals and improve catalytic activity, allowing operation at reduced temperatures with high conversion
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 high yields of distillate boiling range products while minimizing naphtha formation and thermal cracking, with improved catalyst activity and lower operating temperatures.
Implementation Method 1
Amorphous catalysts are provided, along with corresponding systems and methods, for using hydrocracking to improve the yield of liquid products from Fischer-Tropsch synthesis
Implementation Method 2
The catalyst includes base-modified dealuminated USY with a Si/Al ratio prior to base modification and prior to mixing with a binder or support of 2.5 to 20
Implementation Method 3
The extruded silica-alumina support can be extruded from an extrusion mixture containing nitric acid as a peptizing agent and methylcellulose as an extrusion aid
Implementation Method 4
The extruded silica-alumina support can be extruded from an extrusion mixture containing nitric acid as a peptizing agent
Data Source
AI summary
Catalysts and corresponding methods are provided for conversion of Fischer-Tropsch wax to distillate boiling range products. The catalyst for performing the conversion can correspond to a noble metal catalyst supported on an amorphous silica-alumina support. The amorphous silica-alumina support can have a beneficial combination of surface area, pore volume, and acidity that provides for unexpectedly beneficial activity for conversion of Fischer-Tropsch wax. This can allow a target level of conversion during hydrocracking to be achieved at a reduced or minimized temperature and/or reaction severity. The unexpected properties for the amorphous silica-alumina support can be achieved in part by forming the support using an extrusion process where the extrusion mixture includes silica-alumina, nitric acid as a peptizing agent, and methylcellulose as an extrusion aid. The methylcellulose is then removed from the support via calcination, which contributes in part to the properties of the resulting support.