Bimetallic V-Ni Catalyst for Low-Temperature LPG Sweetening
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Solution Overview
Problem
Current mercaptan conversion catalysts for sweetening liquefied petroleum gas (LPG) face challenges such as high operating temperatures, catalyst deactivation, and polymerization of olefins, which lead to inefficiencies and environmental concerns due to the use of alkaline solutions and high hydrogen gas requirements.
Innovation Solution
A bimetallic mercaptan conversion catalyst is developed using an Al2O3-SiO2 composite oxide carrier with vanadium and nickel active components, prepared through an incipient wet impregnation method, allowing for efficient mercaptan conversion at low temperatures (55-150°C) without olefin saturation or polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catalytic oxidation method is used for mercaptan removal, then mercaptan conversion is achieved, but high operating temperature is required causing olefin saturation and polymerization
Solution Approach 1:
The patent changes the key parameter of operating temperature from conventional high temperature (required by traditional catalytic oxidation) to low temperature (50-150°C) by developing a novel bimetallic catalyst system with Al2O3-SiO2 carrier and V-Ni active components, enabling mercaptan conversion under mild conditions without olefin saturation or polymerization
Solution Approach 2:
The patent employs a composite catalyst structure consisting of Al2O3-SiO2 composite oxide carrier combined with V-Ni bimetallic active components. This composite material design synergistically combines the advantages of both metals and the composite carrier, achieving high catalytic activity at low temperature while preventing unwanted side reactions
2Reliability
If traditional mercaptan conversion catalysts are used, then mercaptan removal is achieved, but catalyst deactivation occurs due to sulfide poisoning
Solution Approach 1:
The patent converts the harmful effect of sulfides, which traditionally cause catalyst deactivation, into a beneficial feature by demonstrating that the bimetallic V-Ni catalyst system actually requires sulfides for activation and maintains stable activity in the presence of sulfides, transforming the poison into a necessary component for catalyst functionality
3Reliability
If high hydrogen gas quantity is injected to maintain catalyst activity, then catalyst performance is maintained, but production cost and environmental impact increase
Solution Approach 1:
The patent enables the catalyst to activate and maintain its own activity through the sulfides present in the feedstock itself, eliminating the need for external hydrogen gas injection. The catalyst system is self-sufficient, using the inherent sulfide content of the LPG to maintain optimal catalytic state without additional hydrogen consumption
4Reliability
If alkaline solutions are continuously injected for catalyst stability, then catalyst performance is maintained, but waste emission increases causing environmental pressure
Solution Approach 1:
The patent extracts and eliminates the alkaline solution component from the catalytic system entirely, replacing it with a solid bimetallic catalyst that operates without liquid alkaline additives. This removal of the alkaline solution phase eliminates the source of waste emission while maintaining catalyst stability through the robust bimetallic V-Ni system on Al2O3-SiO2 carrier
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 superior mercaptan conversion performance, stability, and adaptability, nearly completely removing mercaptans and carbonyl sulfide, with improved catalytic activity and reduced environmental impact compared to previous methods.
Implementation Method 1
a bimetallic mercaptan conversion catalyst comprises an Al2O3-SiO2 composite oxide carrier... vanadium and nickel active components... promote oxidation of the thiolate ions... by the oxygen in air to produce a disulfide
Implementation Method 2
promote oxidation of the thiolate ions, as extracted with an alkaline solution, by the oxygen in air to produce a disulfide
Implementation Method 3
loading bimetallic active components, vanadium and nickel, separately onto the Al2O3-SiO2 composite oxide carrier by using an incipient wet impregnation method
Implementation Method 4
calcinating it for 3-8 hours by elevating the temperature to 450-620°C at a heating rate of 2-4°C/min
Data Source
AI summary
The present invention relates to a bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature, which is prepared by using an Al2O3-SiO2 composite oxide as a carrier to support bimetallic active components vanadium and nickel. The bimetallic mercaptan conversion catalyst has a proper specific surface area and more metal active center sites, and has advantages of simple preparation, efficient mercaptan conversion even at a low temperature, and no saturation and polymerization of olefins. The bimetallic mercaptan conversion catalyst exhibits superior mercaptan conversion performance in LPG sweetening, has strong adaptability to starting materials, and can also nearly completely remove trace of carbonyl sulfide contained in LPG.