Two-Stage Gas-Gas Mixer for Flammability Control
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Solution Overview
Problem
Gas-gas mixers in petrochemical processes face challenges in minimizing flammability risks when mixing oxidizing agents and fuels, as local regions within the mixer can become flammable, leading to potential combustion or explosion hazards.
Innovation Solution
A two-stage gas-gas mixer design with a concentric inner and outer pipe arrangement and perforations is used to create a small flammable volume, ensuring effective mixing across a wide range of Reynolds numbers and hydrocarbon to oxidant ratios, and can be scaled up for larger reactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-stage gas-gas mixer is used, then the mixing process is simple, but the flammable volume increases leading to safety hazards
Solution Approach 1:
The mixer is divided into two distinct stages: a first mixing stage with a first set of mixing elements, and a second mixing stage with a second set of mixing elements. This segmentation allows the mixing process to occur in controlled steps, minimizing the volume of flammable gas at any given time while maintaining operational safety.
Solution Approach 2:
The first mixing stage is positioned within or concentric with the second mixing stage, creating a nested configuration where the inner stage handles initial mixing and the outer stage completes the mixing process. This nested arrangement efficiently reduces flammable volume through staged mixing.
2Reliability
If mixing occurs rapidly to reduce flammable volume, then safety improves, but mixing uniformity may be compromised
Solution Approach 1:
The mixing process is segmented into two stages with different mixing elements optimized for different functions: the first stage creates initial dispersion to rapidly reduce flammable volume, while the second stage provides additional mixing action to ensure uniform composition throughout the gas stream.
Solution Approach 2:
Different mixing elements are used in different stages, with each stage having mixing elements specifically designed for its function. The first stage uses elements optimized for rapid dispersion, while the second stage uses elements optimized for achieving uniform mixing, allowing each local region of the mixer to have the quality needed for its specific purpose.
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 design minimizes flammability risks and achieves rapid, uniform mixing, reducing the volume of flammable gas, thereby enhancing safety and operational efficiency.
Implementation Method 1
ensuring effective mixing across a wide range of Reynolds numbers
Data Source
AI summary
A device for mixing two gas streams, the device includes: an inner pipe, wherein: the inner pipe is arranged substantially concentrically within an outer pipe and forms an annulus between an outer diameter of the inner pipe and an inner diameter of the outside pipe; the inner pipe is closed at a downstream end; and the inner pipe comprises a plurality of perforations; and the outer pipe, wherein: a downstream end of the outer pipe extends into a reactor; the outer pipe is closed at the downstream end; and the downstream end of the outer pipe comprises a plurality of perforations. The mixed gas stream can enter the reactor. The reactor can be an Oxidative Coupling of Methane (OCM) reactor.