MIEC Membrane Module for Biomass Gasification Oxygen Generation
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Solution Overview
Problem
Current oxygen production methods for biomass gasification, such as pressure swing adsorption and cryogenic air separation, are energy-intensive and economically unfeasible due to high energy consumption and costs, especially for small-scale oxygen requirements, and existing mixed ionic-electronic conductor (MIEC) membrane systems face stability issues with CO2 and require complex energy recovery systems.
Innovation Solution
A membrane module is directly heated by synthesis gas from biomass gasification, with most heat recovered from exhaust air using high-temperature heat exchangers, and a vacuum or steam is used to generate the driving force for oxygen transport, minimizing electrical energy consumption and preventing membrane contact with corrosive gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional oxygen production methods (PSA or cryogenic air separation) are used, then oxygen can be supplied to biomass gasification, but energy consumption increases significantly (more than 1.0 kWhel./m3 i.N. O2 for small-scale PSA systems)
Solution Approach 1:
The patent changes the operating temperature parameter to high temperatures (above 500°C, preferably 700-900°C) where MIEC membranes exhibit high oxygen permeability. This thermal parameter change enables the membrane to function as an efficient oxygen separator without requiring the electrical energy input needed by PSA or cryogenic systems
Solution Approach 2:
The patent replaces the mechanical/electrical separation systems (PSA compressors, cryogenic compressors) with a thermally-driven membrane separation system. The MIEC membrane uses thermal energy to drive oxygen ion transport through the ceramic material, substituting mechanical compression and phase change processes with solid-state ionic conduction
2Temperature
If MIEC membranes are exposed to CO2-containing gases for heating, then thermal energy can be utilized, but membrane stability decreases due to carbonate formation
Solution Approach 1:
The patent introduces a protective tube as an intermediary barrier between the CO2-containing synthesis gas and the MIEC membrane. This protective tube allows thermal energy transfer from the synthesis gas to heat the membrane while preventing direct contact between CO2 and the membrane surface, thus avoiding carbonate formation and maintaining membrane stability
Solution Approach 2:
The patent segments the heating process into two distinct zones: a protected membrane zone isolated from CO2 by the protective tube, and a combustion zone where synthesis gas can be burned. This spatial segmentation allows thermal energy utilization while protecting the membrane from chemical degradation
3Productivity
If air compression is used to generate driving force for oxygen transport, then oxygen flux increases, but device complexity and energy consumption increase
Solution Approach 1:
The patent changes the driving force mechanism from mechanical compression to thermal activation. By operating at high temperatures (700-900°C), the membrane achieves high oxygen ion conductivity and permeability without requiring compressors or vacuum systems, thus maintaining high oxygen flux while reducing device complexity
Solution Approach 2:
The patent enables the membrane system to self-generate the necessary driving force through thermal energy. The high temperature operation inherently creates the chemical potential gradient needed for oxygen ion transport through the membrane, eliminating the need for external compression or vacuum equipment
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 energy consumption and simplifies system control, enabling efficient and cost-effective oxygen production integrated into biomass gasification processes without the need for additional electrical energy, improving overall process efficiency and reducing costs.
Implementation Method 1
The transport of oxygen is based on the transport of oxide ions through the gas-tight ceramic material and the parallel transport of electronic charge carriers (electrons or defect electrons)
Implementation Method 2
The transport of oxygen is based on the transport of oxide ions through the gas-tight ceramic material and the parallel transport of electronic charge carriers (electrons or defect electrons)
Implementation Method 3
A membrane module is directly heated by synthesis gas from biomass gasification
Implementation Method 4
with most heat recovered from exhaust air using high-temperature heat exchangers
Implementation Method 5
a vacuum or steam is used to generate the driving force for oxygen transport
Data Source
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AI summary
The invention relates to a method and a membrane module for the process-integrated oxygen generation during biomass gasification, the oxygen being generated by means of mixed ionic-electronic conductive ceramic membranes at high temperatures. The aim of the invention is to devise a method and a device for the energy-efficient generation of oxygen during biomass gasification in order to increase the efficiency of the entire process. According to the invention, the disadvantages of the prior art are overcome by a membrane module which is heated directly with the synthesis gas stemming from the biomass gasification. The heating, however, should cover only less than 20% typically less than 10% and, under optimum conditions, only approximately 5% of the heat requirement of the membrane module. The major part of the heat required to heat the fresh air is removed from the exhaust air of the membrane module by heat exchange.