Methane Conversion to Propanal via Integrated OCM and Hydroformylation
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Solution Overview
Problem
Conventional oxidative coupling of methane (OCM) methods face challenges such as high reactivity of products leading to side reactions, costly separation processes, and low efficiency in converting methane to valuable products like ethylene and propanal due to inadequate syngas ratios and hydrogen deficiency.
Innovation Solution
A method involving oxidative coupling of methane with oxygen in a gas phase reaction, followed by thermal cracking to form ethylene, which is then hydroformylated in a second reactor with a controlled syngas ratio adjusted using steam or CO2, utilizing a sulfide catalyst for water gas shift and hydroformylation, eliminating the need for separate syngas production and separation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional OCM reaction is used to convert methane to ethylene, then ethylene production is achieved, but side reactions occur due to high reactivity of products with oxygen leading to low selectivity
Solution Approach 1:
The patent combines OCM reaction with hydroformylation in a single reactor system. The ethylene produced in OCM is immediately consumed in the hydroformylation reaction to form propanal, preventing it from undergoing side reactions with oxygen. This merging of reactions resolves the selectivity problem by removing the harmful interaction between ethylene and oxygen.
Solution Approach 2:
The patent converts the harmful side reactions into beneficial outcomes by using the byproducts (CO and H2 from partial oxidation) as reactants for hydroformylation. The CO and H2 that would normally be considered waste or harmful byproducts are instead utilized as syngas for converting ethylene to propanal, turning a disadvantage into an advantage.
2Productivity
If conventional OCM methods are used, then ethylene is produced, but costly separation processes are required to separate ethylene from unconverted methane and byproducts
Solution Approach 1:
The patent merges OCM and hydroformylation reactions in one reactor, eliminating the need for separate separation units. The continuous conversion of ethylene to propanal within the same reactor system removes ethylene from the mixture before separation is needed, simplifying the overall process and reducing equipment complexity.
Solution Approach 2:
The patent extracts ethylene from the reaction mixture by immediately converting it to propanal through hydroformylation. This in-situ conversion removes ethylene from the mixture of unconverted methane and byproducts, eliminating the need for complex separation processes to isolate ethylene.
3Productivity
If conventional OCM reaction is used, then methane conversion occurs, but inadequate syngas ratio and hydrogen deficiency limit propanal formation efficiency
Solution Approach 1:
The patent converts the CO and H2 byproducts from partial oxidation (which would normally be considered waste) into valuable syngas for hydroformylation. This utilization of byproducts provides adequate syngas ratio and hydrogen for efficient propanal formation, resolving the deficiency problem.
Solution Approach 2:
The reactor system performs multiple functions simultaneously: OCM reaction to produce ethylene, partial oxidation to generate CO and H2, and hydroformylation to convert ethylene to propanal. This multi-functionality ensures adequate syngas supply and hydrogen availability within the same system, eliminating the need for external syngas addition.
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
This approach enhances the conversion of ethylene to propanal, reduces the need for costly separation equipment, and improves process efficiency by optimizing the syngas ratio, thereby increasing the yield of propanal and reducing energy consumption.
Implementation Method 1
oxidative coupling of methane and oxygen (OCM reaction) in a gas phase reaction
Implementation Method 2
forming propanal by hydroformylation of the ethylene with the syngas in a second reactor
Implementation Method 3
utilizing a sulfide catalyst for water gas shift and hydroformylation
Implementation Method 4
forming propanal by hydroformylation of the ethylene with the syngas
Data Source
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AI summary
The present invention provides methods for making propanal in a reaction comprising the oxidative coupling of methane (OCM) and oxygen as a reactant stream in a gas phase reaction, preferably in the presence of water or steam, to form ethylene, ethane, carbon dioxide (CO2), water and syngas (CO and H2) in a first reactor as an ethylene stream, and then forming propanal in a second reactor by feeding to the second reactor the ethylene stream with the syngas from the first reactor in the gas phase and hydroformylating in the presence of a catalyst for a water shift reaction. In the method, the ratio of H2 to CO in the syngas is maintained by either co-feeding steam into the first reactor or the second reactor to generate additional H2 in the syngas, or by forming CO in the second reactor from the water shift reaction by feeding the CO2 from the ethylene stream into the second reactor.