Supersonic Shock Wave Reactor Nozzle Cooling and Feedstock Injection
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Solution Overview
Problem
Conventional methods for producing olefins through shock wave reactors face issues such as nozzle overheating, pressure losses, incomplete mixing of feedstock and carrier gases, and difficulty in controlling rapid temperature changes, leading to carbonization or incomplete reactions.
Innovation Solution
The introduction of feedstock gas through a series of injectors distributed along the reactor, creating plumes that improve mixing and reduce pressure losses, combined with a convergent-divergent nozzle cooled by feedstock gas or steam, and a supersonic diffuser section that balances temperature changes to achieve isothermal flow and controlled thermal cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single nozzle is used to introduce feedstock gas into the carrier gas stream, then the device complexity is reduced, but the mixing completeness deteriorates and pressure losses increase
Solution Approach 1:
The single nozzle is divided into multiple nozzles distributed along the reactor length. Each nozzle introduces feedstock gas at different positions, creating multiple injection points that improve mixing completeness while distributing the complexity across modular components rather than one complex single nozzle
2Loss of energy
If the nozzle is positioned closer to the carrier gas inlet, then the pressure losses are reduced, but the mixing completeness deteriorates
Solution Approach 1:
The injection process is segmented into multiple stages along the reactor length. Nozzles are distributed at different positions, with some closer to the inlet for low pressure loss and others downstream for improved mixing, combining the advantages of both locations
Solution Approach 2:
The injection strategy transitions from a single-point injection (one location) to multi-point injection along the reactor length. This spatial distribution along the longitudinal dimension allows simultaneous optimization of pressure loss (upstream injection) and mixing completeness (downstream injection)
3Device complexity
If the shock wave location is fixed, then the device complexity is reduced, but the temperature control precision deteriorates
Solution Approach 1:
The shock wave location transitions from a fixed static position to a dynamically controllable position. By adjusting operational parameters such as carrier gas flow rate and feedstock gas composition, the shock wave location can be moved to precisely control the temperature profile and reaction conditions without requiring complex mechanical adjustment mechanisms
4Productivity
If the temperature rise across the shock wave is rapid, then the reaction speed is improved, but the temperature control precision deteriorates causing overheating or underheating
Solution Approach 1:
The system incorporates feedback control by monitoring the shock wave location and temperature profile, then adjusting operational parameters (carrier gas flow rate, feedstock gas composition, pressure) to maintain optimal temperature control. This feedback loop preserves rapid reaction speeds while preventing overheating or underheating
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 reduces pressure losses, enhances mixing, and maintains a controlled temperature environment, resulting in improved efficiency and complete conversion of feedstock to olefins with reduced carbonization, achieving higher olefin production rates and product quality.
Implementation Method 1
The transition from supersonic conditions (T2, M2) to subsonic conditions (T3, M3) is accompanied by a rapid temperature rise in the mixture, which promotes conversion from methane and/or the hydrocarbons having single carbon-to-carbon bonds to hydrocarbons having at least some double or triple carbon-to-carbon bonds.
Implementation Method 2
a high temperature carrier gas (e.g., steam at temperature Tco) is fed at an entrance 115 of a subsonic section 110. A feedstock gas 120 (e.g., having hydrocarbons with single carbon-to-carbon bonds or methane (CH4)) is added at some downstream distance from the entrance 115 through nozzles 121
Implementation Method 3
The olefins enter a heat exchanger 150 where they are cooled down to a lower temperature.
Data Source
AI summary
Apparatuses and associated methods for forming olefins from saturated hydrocarbon feedstock are disclosed herein. In one embodiment, a carrier gas is introduced at a supersonic velocity to a feedstock injector section. A feedstock gas is introduced to the carrier gas stream using feedstock injectors that are offset in the streamwise direction one from another. The upstream feedstock injectors are positioned to inject feedstock gas to create plumes that improve penetration depth of the feedstock gas and reduce pressure losses at the downstream feedstock injectors. The feedstock gas can be regeneratively preheated by cooling the convergent-divergent nozzle. Water, steam and/or hydrogen gas can be injected into the apparatus for cooling the throat of the convergent-divergent nozzle.