Oxygen Transport Membrane Reactor Temperature Control
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Solution Overview
Problem
Oxygen transport membrane based reforming systems face challenges such as excessive carbon formation, high costs, complexity, and inefficient thermal coupling due to high operating temperatures, which hinder commercialization and efficiency in producing synthesis gas.
Innovation Solution
A multi-stage reactively driven oxygen transport membrane based reactor system that introduces a specific quantity of cooling air or trim air between stages to maintain consistent surface temperatures, enhancing thermal efficiency and reducing carbon formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperatures (900°C to 1100°C) are used in oxygen transport membrane based reforming reactors, then endothermic heating requirements for steam methane reforming are satisfied, but excessive carbon formation occurs in the hydrocarbon feed stream
Solution Approach 1:
The reforming process is divided into multiple stages with intermediate cooling zones. The reactor is segmented into sections where hydrocarbon reforming occurs at high temperature, followed by cooling sections that reduce temperature before the next reforming stage, preventing excessive carbon formation while maintaining effective reforming in each stage.
Solution Approach 2:
The temperature parameter is dynamically changed throughout the reactor length. High temperatures (900-1100°C) are maintained in reforming zones to satisfy endothermic heating requirements, while intermediate cooling zones reduce temperatures to prevent carbon formation. This parameter variation along the reactor length resolves the contradiction between needing high temperature for reforming and avoiding carbon formation.
2Quantity of substance
If oxygen transport membranes operate at high temperatures, then oxygen flux and membrane performance are improved, but thermal coupling efficiency decreases and operational reliability reduces
Solution Approach 1:
The reactor is divided into multiple stages with alternating high-temperature reforming zones and cooling zones. This segmentation allows oxygen transport membranes to operate at high temperatures where they achieve optimal oxygen flux and performance, while the cooling zones periodically reduce thermal stress, thereby improving operational reliability and preventing membrane degradation.
Solution Approach 2:
Cooling zones are strategically placed before membrane sections to pre-cool the environment, cushioning the thermal stress on membranes. This beforehand cooling protects the membranes from excessive thermal accumulation, maintaining operational reliability while allowing high-temperature operation for optimal oxygen flux.
3Productivity
If preheating of hydrocarbon feed to high temperatures is performed, then reforming reaction efficiency is improved, but carbon formation in the feed stream increases
Solution Approach 1:
The feed preheating and reforming process is segmented into multiple stages. Hydrocarbon feed is progressively heated and reformed in stages rather than subjected to high temperature all at once. Intermediate cooling zones between stages prevent carbon formation that would occur with single-stage high-temperature preheating, while still achieving the necessary temperature for efficient reforming reactions.
Solution Approach 2:
The feed undergoes preliminary reforming at moderate temperatures in earlier stages before entering high-temperature zones. This preliminary action converts some hydrocarbons to synthesis gas at lower temperatures, reducing the hydrocarbon content that would otherwise form carbon at high temperatures, thereby improving overall reforming efficiency while minimizing carbon formation.
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 system achieves improved thermal coupling, reduced carbon formation, and increased operational reliability, making the oxygen transport membrane based reforming process more commercially viable by maintaining consistent surface temperatures and optimizing thermal management.
Implementation Method 1
A typical oxygen transport membrane has a dense layer that, while being impervious to air or other oxygen containing gas, will transport oxygen ions when subjected to an elevated operational temperature and a difference in oxygen partial pressure across the membrane.
Implementation Method 2
the present invention provides a method and apparatus to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reforming reactors by introducing a specific quantity of cooling air or trim air in between stages
Implementation Method 3
the endothermic heating requirements for steam methane reforming reactions occurring within the reformer tubes
Data Source
AI summary
A system and method for temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.