Hydrotreating Catalyst Pore Distribution for Coke Resistance
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Solution Overview
Problem
Existing hydroprocessing catalysts face challenges in balancing surface area and pore diameter for optimal activity and stability, particularly when exposed to high-temperature and high-pressure petroleum feedstocks, leading to rapid deactivation due to coke clogging and reduced mechanical strength.
Innovation Solution
A supported catalyst comprising specific metal components on a porous inorganic oxide carrier with tailored pore size distribution, including 25-45% of pores between 100-200 Angstroms, 15-30% of pores between 200-1000 Angstroms, and 10-30% of pores greater than 1000 Angstroms, enhancing catalyst performance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the catalyst support contains predominantly small pores to maximize surface area, then the concentration of catalytic sites and activity is improved, but the diffusion of reactants to active sites and products from active sites is hindered, and the catalyst is more susceptible to coke clogging
Solution Approach 1:
The pore structure is segmented into multiple size categories (small pores <200 Å for high surface area, medium pores 200-1000 Å for balanced performance, and large pores >1000 Å for low pressure drop and coke resistance). This segmentation allows each pore size to fulfill specific functional requirements simultaneously.
Solution Approach 2:
Different regions of the pore size distribution are assigned different qualities/functions: small pores provide high surface area for catalytic activity, medium pores provide optimal diffusion pathways, and large pores provide mechanical strength and coke resistance. Each local region of the pore distribution serves a specific quality requirement.
2Reliability
If the catalyst support contains larger pores to improve diffusion and reduce pressure drop, then the catalyst life and mechanical strength are improved, but the surface area and concentration of catalytic sites are reduced
Solution Approach 1:
The pore structure is segmented into multiple size categories (small pores <200 Å for high surface area, medium pores 200-1000 Å for balanced performance, and large pores >1000 Å for low pressure drop and coke resistance). This segmentation allows each pore size to fulfill specific functional requirements simultaneously.
Solution Approach 2:
The invention merges the advantages of different pore sizes by combining small pores (high surface area) with large pores (good diffusion and mechanical strength) in a single catalyst support structure, achieving both high catalytic activity and long catalyst life.
3Adaptability or versatility
If the catalyst is exposed to hydrocarbon fractions containing high levels of metals and aromatics to process heavier crude oil, then the processing capability is improved, but the catalyst is rapidly deactivated due to coke clogging and mechanical degradation
Solution Approach 1:
The catalyst support is pre-designed with a robust pore size distribution that provides inherent resistance to coke clogging and mechanical degradation before exposure to harsh feedstocks. The large pores (>1000 Å) act as cushioning pathways that prevent complete pore blockage, while the overall structure maintains mechanical strength under severe conditions.
Solution Approach 2:
The catalyst support employs a composite pore structure combining different pore sizes and types, creating a material that exhibits both high surface area for catalytic activity and enhanced resistance to deactivation. This composite structure integrates the benefits of micropores, mesopores, and macropores into a single robust support system.
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 catalyst achieves improved activity and longevity by optimizing pore distribution, reducing coke deposition and maintaining mechanical strength, suitable for hydrocarbon feedstock treatments like hydrodemetallation and hydrodesulfurization.
Implementation Method 1
the diffusion of the reactants to the active catalyst site, the diffusion of products from the active sites
Implementation Method 2
increasing the hydrogen to carbon (H/C) ratio in the products
Implementation Method 3
cracking carbon bonds to reduce boiling range and average molecular weight
Data Source
AI summary
A supported catalyst for hydroprocessing, hydrotreating or hydrocracking hydrocarbon feedstocks, the supported catalyst comprising at least one metal from Group 6 and at least one metal from Groups 8, 9, or 10 of the Periodic Table of the Elements, and optionally comprising phosphorous. The Group 6 metal comprises about 30 to about 45 wt. % and the total of Group 6 and Group 8, 9, or 10 or mixtures thereof metal components comprise about 35 to about 55 wt. %, calculated as oxides and based on the total weight of the catalyst composition. The metals, and phosphorous when present, are carried on and/or within a porous inorganic oxide carrier or support, the support prior to incorporation of the metals and phosphorus, having a total pore volume (TPV) of about 0.8 cc/g to about 1.5 cc/g and comprising a defined pore size distribution and wherein the supported catalyst comprises a defined pore size distribution.