OTM Reactor Thermal Stabilization via Feed Modulation
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Solution Overview
Problem
Oxygen transport membrane (OTM)-based reforming systems face challenges in maintaining the surface temperature of OTM reactors within a desired range due to excess or inadequate heat production, affecting the oxygen flux and efficiency of syngas production, as there is no direct control over oxygen input and heat management is thermally coupled.
Innovation Solution
The method involves modulating the flow rate of hydrocarbon-containing feed and steam-to-carbon ratio to thermally stabilize the OTM reactor surface temperature between 750° C. to 1000° C, and controlling the oxygen-to-carbon ratio of the syngas product to maintain the system near the thermo-neutral point by adjusting the flow and temperature of the oxygen-containing stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the oxygen transport membrane reactor operates at high temperature to increase oxygen flux, then the syngas production efficiency is improved, but the reactor surface temperature may exceed the target maximum operating temperature causing thermal runaway
Solution Approach 1:
The system implements feedback control by continuously monitoring the OTM reactor surface temperature and adjusting the hydrocarbon-containing feed flow rate accordingly. When temperature exceeds the target range, the feed flow is reduced to cool the reactor; when temperature is below target, feed flow is increased to raise temperature, thereby maintaining stable operating conditions while maximizing syngas production efficiency
Solution Approach 2:
The invention changes the operating parameters by modulating the hydrocarbon-containing feed flow rate and steam-to-carbon ratio to control reactor temperature. This parameter adjustment allows the system to operate at optimal temperatures for high oxygen flux while preventing thermal runaway, thus resolving the contradiction between productivity and temperature control
2Reliability
If the oxygen transport membrane reactor operates at low temperature to maintain safe operating limits, then thermal stability is improved, but the oxygen flux decreases reducing syngas production efficiency
Solution Approach 1:
The system employs dynamic adjustment of the hydrocarbon-containing feed flow rate based on real-time temperature measurements. This dynamic control allows the reactor to operate at high temperatures when conditions permit to maximize productivity, and automatically reduces temperature when approaching safety limits, thus resolving the contradiction between thermal stability and syngas production efficiency
Solution Approach 2:
Feedback control mechanisms continuously monitor reactor temperature and adjust feed flow rates to maintain operation within safe thermal limits while maximizing oxygen flux. This ensures the system achieves high syngas production efficiency without compromising thermal stability or risking thermal runaway
3Ease of operation
If the system operates away from thermo-neutral point to simplify control, then ease of operation is improved, but heat generation does not match heat consumption causing temperature instability
Solution Approach 1:
The system uses feedback control to automatically adjust the hydrocarbon-containing feed flow rate based on real-time temperature measurements, maintaining operation near the thermo-neutral point where heat generation balances heat consumption. This feedback mechanism simplifies control by automatically compensating for temperature deviations, resolving the contradiction between ease of operation and temperature stability
Solution Approach 2:
The invention modulates the steam-to-carbon ratio and hydrocarbon feed flow rate to optimize the operating conditions near the thermo-neutral point. This parameter optimization ensures heat generation matches heat consumption, achieving temperature stability while maintaining relatively simple control operations through automated flow rate adjustment
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 effectively stabilizes the OTM reactor temperature and maintains the oxygen-to-carbon ratio within target ranges, preventing thermal runaway and ensuring efficient syngas production by balancing heat generation and consumption, thereby enhancing the operational reliability and efficiency of the OTM-based reforming system.
Implementation Method 1
the oxygen transport membrane reactor is configured to separate oxygen from an oxygen-containing stream to produce an oxygen permeate and an oxygen-depleted retentate stream
Implementation Method 2
reacting a portion of the partially-reformed synthesis gas stream with oxygen permeated through the at least one oxygen transport membrane reactor to produce a difference in oxygen partial pressure across the oxygen transport membrane reactor and generate a steam-containing heated reaction product stream and heat
Implementation Method 3
transferring the heat generated as a result of the reaction via convection to the oxygen-depleted retentate stream and via radiation and convection to at least one catalyst-containing reforming reactor
Implementation Method 4
partially reforming a combined feed stream comprising a hydrocarbon-containing feed stream and steam in the presence of heat in said reforming reactor to produce a partially-reformed synthesis gas stream
Data Source
AI summary
A method of operating an oxygen transport membrane based reforming system employing one or more packs of thermally coupled panels of reformer tubes and oxygen transport membrane (“OTM”) reactors close to thermo-neutral point is provided. The method produces syngas by converting a hydrocarbon-containing feed, such as natural gas in the reformer tubes of a pack by endothermic steam reforming reactions. The heat required for endothermic reforming reactions is provided by exothermic oxidizing reactions occurring inside the OTM reactors of the pack. At a thermo-neutral point the heat released by exothermic reactions matches the heat required to support endothermic reactions and heat losses in the pack. The method modulates the flow rate of hydrocarbon-containing feed and/or steam-to-carbon ratio of the combined feed to the pack to maintain the surface temperature of oxygen transport membrane reactors below a target maximum temperature. The syngas product oxygen-to-carbon ratio is maintained within a desired target range such that the OTM based reforming system is operated close to thermo-neutral point.