Fibrous Substrate Hydroprocessing Catalysts
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Solution Overview
Problem
Conventional hydroprocessing catalysts face challenges in maintaining activity and selectivity, especially under liquid-rich conditions where hydrogen is not in excess, leading to poor mass transfer and stability, which increases costs and equipment requirements.
Innovation Solution
Development of catalysts with fibrous substrates having silica-containing fibers of smaller diameters, converted into zeolites or non-zeolitic molecular sieves, providing enhanced surface area and tailored acidity for improved cracking activity and mass transfer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional hydroprocessing catalysts are used under liquid-rich conditions, then hydrogen requirements are reduced, but mass transfer and catalyst stability deteriorate
Solution Approach 1:
The patent employs fibrous substrates with inherently porous structures that provide extensive internal surface area for catalytic reactions. The fibrous morphology creates a three-dimensional network with interconnected pores, enabling efficient mass transfer of hydrogen and hydrocarbon molecules while maintaining catalyst stability under liquid-rich conditions where hydrogen is not in excess
Solution Approach 2:
The catalyst comprises composite structures combining fibrous substrates (providing mechanical strength and porosity) with deposited zeolite or molecular sieve crystals (providing catalytic activity). This composite approach allows the fibrous support to enhance mass transfer while the crystalline catalyst particles provide stable catalytic function, resolving the contradiction between reduced hydrogen requirements and maintained catalyst stability
2Productivity
If conventional hydroprocessing catalysts are used, then standard reactor designs are employed, but equipment size and operational costs increase
Solution Approach 1:
The fibrous substrates possess high porosity and large surface area-to-volume ratios, which dramatically increase the effective catalytic surface area within a given reactor volume. This allows for more compact reactor designs that achieve the same or higher productivity with reduced equipment size and lower operational costs
Solution Approach 2:
The fibrous structure transitions from conventional two-dimensional planar catalyst supports to three-dimensional fibrous networks, creating additional reaction pathways and surface area in the vertical dimension. This dimensional enhancement allows for more efficient space utilization in reactors, reducing overall equipment size while maintaining or improving productivity
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
The catalysts exhibit superior cracking activity and stability, allowing for efficient hydroprocessing in liquid phase with reduced hydrogen requirements, enabling smaller reactor designs and lower hydrogen recovery needs, thus reducing operational costs and enhancing process efficiency.
Implementation Method 1
a zeolite that is deposited on the fibers and that is formed from components of these fibers
Implementation Method 2
converted into zeolites or non-zeolitic molecular sieves
Implementation Method 3
contacting it with hydrogen in the presence of a catalyst
Implementation Method 4
hydroprocessing processes, generally involving reactions between hydrogen and hydrocarbons... are carried out in the presence of a catalyst
Data Source
AI summary
Catalysts are disclosed comprising fibrous substrates having silica-containing fibers with diameters generally from about 1 to about 50 microns, which act effectively as “micro cylinders.” Such catalysts can dramatically improve physical surface area, for example per unit length of a reactor or reaction zone. At least a portion of the silica, originally present in the silica-containing fibers of a fibrous material used to form the fibrous substrate, is converted to a zeolite (e.g., having a SiO2/Al2O3 ratio of at least about 150) that remains deposited on these fibers. The fibrous substrates possess important properties, for example in terms of acidity, which are useful in hydroprocessing (e.g., hydrotreating or hydrocracking) applications.