Supersonic Methane Pyrolysis for Butanediol Production
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Solution Overview
Problem
Traditional pyrolysis processes are inefficient and costly for converting methane into valuable hydrocarbons like ethylene, and existing methods using oxygenates as intermediates incur energy and cost penalties, while supersonic flow reactors have not been effectively scaled for commercial methane pyrolysis due to contaminant issues and product purity challenges.
Innovation Solution
A supersonic flow reactor is used to pyrolyze methane, producing acetylene, which is then processed with formaldehyde over a catalyst to form butanediol, with additional steps for contaminant removal and separation to enhance product yield and purity, including the use of hydrogenation and dimerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional pyrolysis processes are used to convert methane to hydrocarbons, then the process is simple and well-established, but the energy consumption is high and production costs are high
Solution Approach 1:
The patent changes key process parameters by using supersonic flow conditions (Mach numbers > 1) instead of conventional subsonic pyrolysis conditions. This creates extremely short residence times (milliseconds) and high expansion ratios, fundamentally altering the reaction kinetics and product distribution to achieve lower energy consumption while maintaining process simplicity
Solution Approach 2:
The patent employs periodic pulsed operation where methane is introduced in pulses into the supersonic flow reactor. This periodic action allows for better control of residence time and heat transfer, improving energy efficiency while maintaining the simplicity of the overall process design
2Adaptability or versatility
If oxygenates like methanol are used as intermediate feedstocks, then alternative feedstock sources become available, but energy penalties and cost penalties increase
Solution Approach 1:
The patent extracts and eliminates the oxygenate intermediate step from the conventional conversion pathway. By directly pyrolyzing methane to hydrocarbons in a supersonic flow reactor, the process removes the energy-intensive methanol synthesis and conversion steps, achieving feedstock flexibility through direct methane utilization without oxygenate intermediates
Solution Approach 2:
The patent introduces supersonic expansion as a new intermediary mechanism that enables direct conversion of methane to hydrocarbons. This supersonic expansion acts as a mediator that facilitates the difficult C-H bond breaking and restructuring without requiring oxygenate intermediates, thereby reducing energy penalties while maintaining adaptability
3Productivity
If supersonic flow reactors are used for methane pyrolysis, then acetylene yield increases, but contaminant issues and product purity challenges arise
Solution Approach 1:
The patent converts the harmful effect of high-temperature side reactions that produce contaminants into a benefit by using supersonic expansion to rapidly quench the reaction. The extreme cooling rates freeze the product distribution at desired conversion levels, preventing further decomposition and contaminant formation, thus maintaining high acetylene yield and purity simultaneously
Solution Approach 2:
The patent replaces conventional thermal management and separation systems with supersonic expansion dynamics. The mechanical energy of supersonic flow is converted to thermal energy and then rapidly dissipated through expansion, providing inherent product protection and separation without complex mechanical systems, thereby maintaining both high yield and purity
4Productivity
If residence time is reduced in conventional pyrolysis, then desired product yield increases and by-product formation decreases, but there is little room left for further improvement
Solution Approach 1:
The patent transitions from conventional one-dimensional residence time control to multi-dimensional control by introducing supersonic flow parameters (Mach number, expansion ratio, shock wave position). This adds new dimensions to the process space, allowing further improvement of product yield beyond the limits of conventional residence time reduction
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 method achieves a higher yield of acetylene from methane compared to traditional methods and produces butanediol efficiently, addressing contaminant-related issues and energy costs by optimizing the supersonic reactor process for commercial-scale methane conversion.
Implementation Method 1
pyrolyzing the methane in the supersonic reactor to form a reactor effluent stream portion of the hydrocarbon stream including acetylene
Implementation Method 2
A supersonic flow reactor is used to pyrolyze methane
Implementation Method 3
processed with formaldehyde over a catalyst to form butanediol
Implementation Method 4
including the use of hydrogenation and dimerization reactions
Data Source
AI summary
Methods and systems are provided for converting methane in a feed stream to butanediol. The method includes processing acetylene as an intermediate stream to form a hydrocarbon stream including butanediol. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream is treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of carbon monoxide to prevent undesired reactions in downstream processing units.