Air Separation Purity Control Using Nitrogen-Diluted Oxygen
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Solution Overview
Problem
Air separation units (ASUs) in gasification plants are expensive and energy-intensive, contributing significantly to the cost and inefficiency of integrated gasification combined cycle (IGCC) power plants due to their high energy consumption and large capital costs.
Innovation Solution
The system and method involve an ASU configured to separate air into an oxygen-rich stream and a nitrogen-rich stream, with a purity control system that adjusts the oxygen and nitrogen percentages based on a target diluent level, allowing the oxygen-rich stream to include nitrogen as a diluent, thereby reducing the need for a separate diluent stream and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ASU separates air into high-purity oxygen stream, then oxygen purity is improved, but energy consumption increases and device complexity increases
Solution Approach 1:
The invention changes the purity parameter of the oxygen stream from high-purity to controlled-purity (containing 5-50% nitrogen), which reduces the separation requirements and energy consumption of the ASU while still meeting the process needs for oxygen and diluent
Solution Approach 2:
The invention merges the oxygen stream and diluent stream into a single combined stream that is directly supplied to the gasifier, eliminating the need for separate production and mixing processes, thereby reducing overall system complexity and energy usage
2Manufacturing precision
If the ASU produces high-purity oxygen stream, then oxygen concentration is improved, but device complexity and capital cost increase
Solution Approach 1:
The invention combines the functions of oxygen production and diluent supply into a single ASU output stream, eliminating the need for separate high-purity oxygen generation and separate diluent mixing equipment, thereby reducing device complexity
Solution Approach 2:
The ASU is designed to produce a multi-functional stream that simultaneously provides oxygen for combustion and nitrogen as diluent for temperature control, making the system more versatile and reducing the need for multiple specialized units
3Adaptability or versatility
If separate oxygen and diluent streams are produced, then process control flexibility is improved, but energy consumption and device complexity increase
Solution Approach 1:
The invention changes the composition parameter of the oxygen stream to include controlled amounts of nitrogen (5-50%), which allows the stream to inherently provide both oxygen and diluent functions, reducing the need for complex separate stream handling while maintaining process flexibility through adjustable composition
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 results in a more efficient and cost-effective ASU that is smaller and less complex, reducing energy consumption and capital costs by integrating nitrogen as a diluent within the oxygen-rich stream, thus improving the overall efficiency of the gasification process.
Implementation Method 1
an air separation unit configured to separate air into an oxygen rich stream and a nitrogen rich stream
Data Source
AI summary
A system includes an air separation unit configured to separate air into an oxygen rich stream and a nitrogen rich stream and a purity control system configured to receive input indicative of a target diluent level. The purity control system is configured to control the air separation unit to adjust an oxygen percentage and a nitrogen percentage of the oxygen rich stream based on the target diluent level.