Feedstock Pyrolysis via Oxidant Injection and Auto-Ignition Control
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Solution Overview
Problem
Existing thermal pyrolysis methods face challenges such as high temperatures and pressures leading to detonation risks, inefficient energy transfer, and energy loss due to active cooling, which can damage components and reduce combustion energy delivery.
Innovation Solution
A method involving pre-heating a feedstock and injecting an oxidant, such as pure oxygen, into a flowing stream of the feedstock to induce auto-ignition and decomposition, using multiple nozzle configurations to enhance mixing and control ignition, thereby optimizing energy transfer and reducing detonation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If combustion products are generated in an enclosed combustion chamber by combusting a fuel-oxidant mixture, then thermal energy is produced to drive pyrolysis, but the high temperatures and pressures increase the likelihood of detonation and may compromise components such as injection nozzles and refractories
Solution Approach 1:
The system divides the combustion process into two separate spatial zones: a combustion chamber for fuel oxidation and a reaction chamber for feedstock pyrolysis. This segmentation prevents the feedstock from being exposed to the high-pressure combustion environment while still allowing it to receive thermal energy from the combustion products, thereby resolving the contradiction between achieving high combustion temperatures and maintaining component integrity.
2Loss of energy
If the temperature of the combustor is increased to reduce the differential temperature between combustor and combustion products, then heat transfer efficiency is improved, but this may trigger auto-ignition of the pre-mixed fuel and oxidant entering the combustion chamber
Solution Approach 1:
The system pre-heats the feedstock in the reaction chamber to a temperature sufficient for pyrolysis before introducing it to the combustion products. This preliminary heating action allows the feedstock to be ready for decomposition without requiring the combustor temperature to be excessively high, thereby preventing auto-ignition of the fuel-oxidant mixture while maintaining efficient heat transfer.
3Reliability
If the combustion chamber and internal components are actively cooled to avoid auto-ignition of the combustible mixture, then auto-ignition is prevented, but this cooling load extracts significant heat and energy otherwise intended to drive the pyrolysis reaction
Solution Approach 1:
The system extracts the feedstock from the combustion chamber environment and processes it separately in the reaction chamber. The feedstock is pre-heated and then exposed to combustion products without being part of the combustible mixture in the combustion chamber. This extraction eliminates the need for active cooling to prevent auto-ignition, as the feedstock is not mixed with fuel and oxidant in the high-temperature zone, thereby preventing energy loss from cooling loads.
4Temperature
If combustion products are used to drive pyrolysis, then thermal energy is provided for decomposition, but lower-than-desired combustion energy is delivered to the reaction chamber
Solution Approach 1:
The system merges the thermal energy from combustion with the pre-heated feedstock in the reaction chamber. The combustion products, carrying thermal energy, are directed into the reaction chamber where they transfer heat to the pre-heated feedstock, driving pyrolysis. This combining of thermal energy transfer with the pre-heated feedstock ensures efficient energy delivery to achieve the required pyrolysis temperature.
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 allows for controlled pyrolysis with improved energy efficiency, reduced risk of detonation, and effective decomposition of feedstocks like methane, hydrogen, and carbon monoxide, producing hydrogen and carbon products while minimizing component damage.
Implementation Method 1
at least a first portion of the pre-heated feedstock auto-ignites and causes at least a second portion of the pre-heated feedstock to decompose
Implementation Method 2
decompose into one or more products by pyrolysis
Implementation Method 3
pre-heating a feedstock to within a range of 500 degrees C. to 1,125 degrees C.
Data Source
AI summary
A method of decomposing a pre-heated feedstock includes flowing a stream of the pre-heated feedstock and injecting an oxidant into the flowing stream of pre-heated feedstock. The oxidant mixes with the pre-heated feedstock and, in response to the mixing, at least a first portion of the pre-heated feedstock auto-ignites and causes at least a second portion of the pre-heated feedstock to decompose into one or more products by pyrolysis.