Hydrorefining Catalyst Preparation via Polyamine Complexation
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Solution Overview
Problem
Current methods for preparing hydrorefining catalysts with cobalt and molybdenum active components face challenges such as poor dissolution, high preparation costs, and instability due to the need for multi-step processes and organic additives, leading to inadequate dispersion and activity.
Innovation Solution
A one-step impregnation method using a mixed solvent of aqueous ammonia and a polyamine complexing agent to form a clear, stable impregnation solution with low surface tension and viscosity, allowing for high dispersion of active components without heating, and subsequent thermal activation to enhance catalyst stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a one-step impregnation method is used to reduce preparation cost and simplify the process, then the preparation cost decreases and process complexity is reduced, but the active components are difficult to dissolve and disperse uniformly, leading to poor catalyst activity and selectivity
Solution Approach 1:
The patent introduces a complexing agent as an intermediary substance that facilitates the dissolution and uniform distribution of active components (Co, Mo, Ni, W) in the impregnation solution. The complexing agent forms stable complexes with these components, enabling them to dissolve completely and disperse uniformly on the catalyst support during one-step impregnation, thereby resolving the contradiction between simplified process and poor dispersion.
Solution Approach 2:
The patent adjusts the pH value of the impregnation solution to 9-14 (optimally 11-13) and controls the concentration of the complexing agent to optimize the dissolution and dispersion of active components. By changing these parameters, the solution achieves complete dissolution of active components with uniform distribution, maintaining high catalyst activity and selectivity while using a simplified one-step process.
2Productivity
If organic acid/base is added to promote dissolution of active components, then the dissolution efficiency improves, but a large amount of organic acid/base is required when high content of active components is needed, increasing cost and complexity
Solution Approach 1:
The patent optimizes the pH value of the impregnation solution to 9-14 and adjusts the complexing agent concentration to achieve complete dissolution of active components. This parameter optimization enables efficient dissolution with minimal additive quantities, avoiding the need for large amounts of organic acid/base while maintaining high productivity.
3Reliability
If high content of active components is required to improve catalyst activity, then the catalyst activity increases, but a large amount of organic acid/base needs to be used, increasing preparation cost
Solution Approach 1:
The complexing agent acts as a mediator that enables complete dissolution and uniform dispersion of high concentrations of active components (Co, Mo, Ni, W) in the impregnation solution. This allows the preparation of catalysts with high active component content (achieving high catalyst activity) without requiring large amounts of organic additives, thereby maintaining cost-effectiveness.
4Manufacturing precision
If multi-step impregnation method is used to improve dispersion of active components, then the dispersion degree improves, but the preparation cost increases and the process becomes more complex
Solution Approach 1:
The complexing agent serves as a powerful intermediary that enables complete dissolution and uniform distribution of multiple active components (Co, Mo, Ni, W) simultaneously in a single impregnation step. This eliminates the need for multi-step impregnation processes while achieving excellent dispersion, thereby simplifying the process without sacrificing manufacturing precision.
Solution Approach 2:
The patent combines multiple active components (Co, Mo, Ni, W) and the complexing agent into a single impregnation solution, allowing all components to be impregnated simultaneously in one step. This merging of multiple impregnation steps into one achieves the same dispersion quality as multi-step methods while reducing process complexity.
5Reliability
If during calcination high temperature is applied to activate the catalyst, then the catalyst stability improves, but temperature runaway easily occurs, a large amount of gas is discharged, and loss of catalyst is serious
Solution Approach 1:
The patent performs preliminary drying of the impregnated catalyst at 105-120°C for 2-6 hours before calcination to remove physically adsorbed water. This preliminary action prevents sudden vaporization and temperature runaway during subsequent high-temperature calcination, allowing safe activation while maintaining catalyst stability.
Solution Approach 2:
The patent employs a continuous, staged heating process during calcination: first drying at 105-120°C to remove physical water, then gradually heating to 300-600°C for 3-8 hours to remove chemically bound water and activate the catalyst. This continuous, controlled heating avoids temperature runaway while achieving complete activation and high catalyst stability.
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 method achieves high catalyst activity, selectivity, and stability with reduced loss rates and production costs, improving long-term operational performance and hydrogenation efficiency.
Implementation Method 1
adding a polyamine complexing agent to form a mixed solvent; adding a salt containing the active component cobalt to the mixed solvent and dissolving
Implementation Method 2
subsequent thermal activation to enhance catalyst stability
Data Source
AI summary
A method for preparing hydrorefining catalyst comprises the following steps: (1) mixing an aqueous ammonia solution with a polyamine complexing agent to form a mixed solvent; (2) adding a cobalt salt to the mixed solvent, dissolving the cobalt salt, and then adding a molybdenum salt and optional salts of other active components, and dissolving them to prepare an impregnating solution; and (3) impregnating a support with the impregnating solution, followed by aging, drying, and activating the impregnated support to form a hydrorefining catalyst. The hydrorefining catalyst prepared by this method has good activity, selectivity and stability in use.