Multi-Metallic Catalyst Pore Tuning for Heavy Oil Hydroconversion
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Solution Overview
Problem
The petroleum industry faces challenges in using catalysts for the hydroconversion of heavy, lower-grade hydrocarbons due to the limitations of existing catalysts in terms of porosity and surface area, which affects their catalytic activity and efficiency in refining heavy oil feeds.
Innovation Solution
A stable bulk multi-metallic catalyst is developed using a catalyst precursor with a Type IV isotherm and H3-type hysteresis loop, characterized by tunable mesopores and a poorly crystalline structure, formed through a process involving precipitation, shaping, and sulfidation, which enhances the catalyst's porosity and surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a catalyst is made highly porous to increase surface area, then the accessible surface area increases, but the catalytic activity decreases due to very little surface area and low reactive sites
Solution Approach 1:
The patent optimizes the pore size distribution and surface area parameters of the catalyst to achieve a balance between accessibility and reactivity. By controlling the crystallization process and using specific pore-forming agents, the catalyst achieves an optimal pore structure that provides both high surface area and sufficient reactive sites for hydroconversion reactions.
Solution Approach 2:
The patent employs multi-metallic catalyst compositions combining different metals (such as Ni, Co, Mo, W) to create composite catalytic materials. This allows the catalyst to leverage the complementary properties of different metals, achieving both high surface area accessibility and high catalytic activity for heavy oil hydroconversion.
2Volume of moving object
If macroporous solids are used as catalysts, then the pore size is large for heavy oil access, but the surface area is low reducing catalytic efficiency
Solution Approach 1:
The patent creates a hierarchical pore structure with multiple levels of porosity, including macro pores for bulk transport and meso/micro pores for catalytic reactions. This segmented pore architecture allows heavy oil molecules to access the catalyst through large pores while reacting on the high-surface-area smaller pores, resolving the contradiction between pore size and surface area.
Solution Approach 2:
The patent transitions from a single-pore-size approach to a multi-dimensional pore size distribution, incorporating micropores, mesopores, and macropores in a hierarchical structure. This dimensional approach to porosity allows simultaneous optimization of molecular access (macropores) and catalytic surface area (meso/micropores).
3Volume of stationary object
If the catalyst precursor undergoes extensive processing to improve porosity, then the pore structure improves, but the manufacturing complexity increases
Solution Approach 1:
The patent incorporates pore-forming agents and structure-directing agents during the initial catalyst synthesis stage, allowing the desired pore structure to form during crystallization. This preliminary structuring eliminates the need for subsequent complex pore-modification steps, reducing manufacturing complexity while achieving the target pore volume.
Solution Approach 2:
The patent utilizes controlled crystallization and phase transition processes to spontaneously generate the desired porous structure during catalyst formation. By controlling temperature, pressure, and chemical environment during synthesis, the catalyst develops an optimized pore structure through natural phase transitions rather than mechanical processing.
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 exhibits improved catalytic activity and stability, achieving high conversion rates and low sulfur levels in heavy oil feeds, making it suitable for hydrotreating processes, particularly effective for heavy petroleum feeds with high boiling points.
Implementation Method 1
sulfiding the shaped catalyst precursor forming a bulk multi-metallic catalyst
Implementation Method 2
the amount of ligating agent is controlled to vary or tune the mesopores of the catalyst precursor
Implementation Method 3
treating the feedstocks with hydrogen in the presence of catalysts to effect conversion of at least a portion of the feeds to lower molecular weight hydrocarbons
Implementation Method 4
forming a precipitate comprising at least a promoter metal precursor, at least a Group VIB metal precursor
Data Source
AI summary
The invention relates to a bulk multi-metallic catalyst for hydrotreating heavy oil feeds and to a method for preparing the catalyst. The bulk multi-metallic catalyst is prepared by sulfiding a catalyst precursor having a poorly crystalline structure with disordered stacking layers, with a type IV adsorption-desorption isotherms of nitrogen with a hysteresis starting point value of about 0.35, for a sulfided catalyst that will facilitate the reactant's and product's diffusion in catalytic applications. In another embodiment, the precursor is characterized as having a type H3 hysteresis loop. In a third embodiment, the hysteresis loop is characterized as having a well developed plateau above P/Po of about 0.55. The mesapores of the precursor can be adjustable or tunable.