Hybrid Catalyst Syngas Conversion for Low CO2 Selectivity
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Solution Overview
Problem
Existing hydrocarbon synthesis processes face a challenge in achieving high productivity of C2 to C4 hydrocarbons while maintaining low net carbon dioxide (CO2) selectivity, as co-feeding CO2 to reduce CO2 selectivity often results in decreased productivity.
Innovation Solution
A process that introduces an additional stream of CO2 and operates at a gas hourly space velocity exceeding 2500 hr−1, using a hybrid catalyst comprising a mixed metal oxide and a microporous component, to convert syngas into C2 to C4 hydrocarbons with a net CO2 selectivity of less than 5.0% and productivity greater than 75 g hydrocarbons per kilogram of catalyst per hour.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If CO2 is co-fed to reduce net CO2 selectivity, then CO2 selectivity is reduced, but productivity of C2 to C4 hydrocarbons decreases
Solution Approach 1:
The patent applies parameter changes by operating at a specific gas hourly space velocity range (2000-5000 hr⁻¹) and controlling the CO2/CO ratio in the combined stream (0.05-1.50). This optimization of process parameters enables simultaneous reduction of net CO2 selectivity and maintenance of high hydrocarbon productivity, resolving the technical contradiction between these two opposing objectives.
Solution Approach 2:
The patent employs a hybrid catalyst comprising a mixed metal oxide component and a microporous catalyst component. This composite catalyst system synergistically combines the CO2 tolerance and activity of mixed metal oxides with the shape-selective properties of microporous materials, enabling the process to achieve low CO2 selectivity while maintaining high productivity.
2Productivity
If gas hourly space velocity is increased to maintain productivity, then productivity is maintained, but CO2 selectivity increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the gas hourly space velocity to a specific range (2000-5000 hr⁻¹) and simultaneously controlling the CO2/CO ratio (0.05-1.50). This coordinated parameter optimization ensures that high space velocity maintains productivity while the controlled CO2/CO ratio prevents excessive CO2 selectivity.
Solution Approach 2:
The process implements feedback control by monitoring and adjusting the CO2/CO ratio in the combined stream based on the desired net CO2 selectivity and productivity targets. This feedback mechanism allows dynamic optimization of the gas composition to maintain both high productivity and low CO2 selectivity at elevated space velocities.
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 process effectively reduces net CO2 selectivity while maintaining or enhancing the production of C2 to C4 hydrocarbons, balancing CO2 reduction with productivity through high space velocity and hybrid catalyst utilization.
Implementation Method 1
converting a combined stream comprising the feed stream and the additional stream into a product stream comprising C2 to C4 hydrocarbons in the reaction zone in the presence of a hybrid catalyst
Data Source
AI summary
A process for preparing C2 to C4 hydrocarbons includes introducing a feed stream into a reaction zone of a reactor, the feed stream comprising hydrogen gas and carbon monoxide. An additional stream is introduced into the reaction zone of the reactor, the additional stream comprising carbon dioxide. A combined stream that includes the feed stream and the additional stream is converted into a product stream comprising C2 to C4 hydrocarbons in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a mixed metal oxide catalyst component, and a microporous catalyst component. The process operates at a gas hourly space velocity in excess of 2500 hr−1 and effectively yields a net carbon dioxide selectivity of less than 5.0% and a productivity of C2-C4 hydrocarbons greater than 75 g hydrocarbons per kilogram of catalyst per hour.