Ga2O3/La2O3-γAl2O3 Catalyst for CO2 Propane ODH Selectivity
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Solution Overview
Problem
Existing methods for propylene production, such as steam cracking and fluid catalytic cracking, suffer from diminished selectivity, and oxidative dehydrogenation processes using oxygen face challenges like olefin over-oxidation, while CO2-based routes face activation hurdles due to thermodynamic stability, necessitating a chromium-free catalyst with high selectivity and yield.
Innovation Solution
A Ga2O3/La2O3-γAl2O3 composite catalyst is developed, where Ga2O3 particles are deposited on a matrix of rough and irregular-sized La2O3 and alumina particles, facilitating propane conversion to propylene with up to 95% conversion and 60% yield under controlled conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chromium-based catalysts are used for CO2-OPDH, then high catalytic activity is achieved, but environmental toxicity and harmful effects increase
Solution Approach 1:
The patent replaces expensive and toxic chromium-based catalysts with a cheaper, environmentally friendly Ga2O3-La2O3 catalyst system. The gallium and lanthanum oxides serve as effective alternatives that achieve comparable catalytic activity without the environmental harm associated with chromium, embodying the principle of substituting harmful materials with benign ones.
Solution Approach 2:
The patent employs a composite catalyst system consisting of Ga2O3 and La2O3 combined on a support material. This composite approach allows the synergistic interaction between different oxide components to achieve high catalytic activity while maintaining environmental compatibility, replacing the single-component chromium-based catalysts.
2Productivity
If oxygen is used as oxidant in OPDH, then the reaction proceeds efficiently, but olefin over-oxidation occurs
Solution Approach 1:
The patent changes the oxidant parameter from strong oxidizing oxygen to milder CO2 as the oxidant. This parameter change in the oxidation process allows the reaction to proceed with sufficient efficiency while preventing the over-oxidation of olefin products that occurs with oxygen, as CO2 is a gentler oxidizing agent.
Solution Approach 2:
The patent converts the typically harmful greenhouse gas CO2 into a beneficial mild oxidant for the dehydrogenation reaction. By utilizing CO2 as the oxidant instead of oxygen, the process achieves the desired dehydrogenation while avoiding the harmful over-oxidation side reactions, effectively turning a waste product into a useful reagent.
3Object-generated harmful factors
If CO2 is used as oxidant in OPDH, then olefin over-oxidation is avoided, but activation becomes difficult due to thermodynamic stability
Solution Approach 1:
The patent uses a composite catalyst system combining Ga2O3 and La2O3 to overcome the activation difficulty of CO2. The synergistic interaction between these two oxides creates active sites that can effectively activate the thermodynamically stable CO2 molecule, enabling it to function as a reactive oxidant despite its stability.
Solution Approach 2:
The patent creates specific local active sites on the catalyst surface where CO2 activation occurs. The Ga2O3-La2O3 composite provides localized regions with appropriate electronic and geometric properties that facilitate CO2 activation, allowing the reaction to proceed selectively at these specific sites while maintaining overall 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 catalyst achieves high propane conversion and propylene yield, overcoming the limitations of individual catalysts by combining their advantages and minimizing over-oxidation, while utilizing a mild oxidant like CO2.
Implementation Method 1
Ga2O3 particles at least partially disposed on surfaces of a matrix containing rough and irregular-sized La2O3 and alumina particles... to convert at least a portion of the propane to propylene
Implementation Method 2
Ga2O3 particles at least partially disposed on surfaces of a matrix containing rough and irregular-sized La2O3 and alumina particles... facilitating propane conversion to propylene
Data Source
AI summary
A method for producing propylene (C3H8) via oxidative dehydrogenation (ODH) of propane includes introducing a propane-containing feed gas stream into a reactor containing an alumina-supported Ga2O3/La2O3 catalyst comprising Ga2O3 particles at least partially disposed on surfaces of a matrix comprising rough and irregular-sized La2O3 and alumina particles; passing the propane-containing feed gas stream through the reactor in contact with the alumina supported Ga2O3/La2O3 catalyst at a temperature of 500 to 600° C. to convert at least a portion of the propane to propylene (C3H6) and produce a propylene-containing gas stream leaving the reactor; and separating the propylene from the propylene-containing gas stream. The method has a propane conversion of up to 95% based on an initial weight of the propane in the propane-containing feed gas stream, and a propylene yield of up to 60% based on the propane conversion.