Method for compressing an incoming feed air stream in a cryogenic air separation plant
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Solution Overview
Problem
Cryogenic air separation plants face high energy costs due to inefficient compression processes, with conventional systems consuming significant power and lacking flexibility to adjust to varying operating conditions such as ambient temperature changes and flow rates.
Innovation Solution
Implementing a method using two direct drive compression assemblies with variable speed drive assemblies to control the compression of incoming feed air streams, allowing for adjustable speed ratios and improved turndown capabilities, thereby optimizing energy use and reducing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional fixed-speed compression systems are used, then the system structure is simple, but energy consumption is high and adaptability to varying operating conditions is poor
Solution Approach 1:
The patent applies dynamics by replacing fixed-speed compression systems with variable-speed direct-drive compression assemblies. The compression assemblies can adjust their rotational speed dynamically to match varying operating conditions such as ambient temperature changes and flow rate requirements. This enables the system to operate at optimal efficiency points across different loading conditions, significantly reducing energy consumption compared to fixed-speed systems that must operate at constant speed regardless of actual demand.
Solution Approach 2:
The patent implements parameter changes by allowing the compression assemblies to vary their rotational speed parameter in response to changing operating conditions. The control system monitors parameters such as inlet temperature, pressure, and flow rate, and adjusts the compression assembly speed accordingly. This dynamic parameter adjustment enables the system to maintain high efficiency across a wide range of operating conditions while adapting to seasonal and daily variations in air separation plant requirements.
2Adaptability or versatility
If single-stage compression is used, then the device complexity is low, but the turndown capability and operational flexibility are limited
Solution Approach 1:
The patent applies segmentation by dividing the compression function into multiple independent direct-drive compression assemblies rather than using a single complex multi-stage compressor. Each compression assembly can be independently controlled and adjusted, allowing the system to achieve high turndown ratios by operating one or more assemblies at reduced speeds or by taking assemblies offline. This modular segmented approach provides operational flexibility while keeping individual assembly structures relatively simple.
Solution Approach 2:
The patent implements universality by designing the direct-drive compression assemblies to perform multiple functions across different operating conditions. Each assembly is capable of operating efficiently across a wide speed range and can adapt to various discharge pressure requirements. The universal design allows the same basic assembly configuration to serve both base-load and part-load operations, as well as to handle different product delivery requirements, thereby enhancing overall system versatility without requiring specialized equipment for each function.
3Productivity
If conventional compression systems are used, then the initial investment cost is lower, but operational efficiency and energy management are inferior
Solution Approach 1:
The patent applies feedback by implementing a control system that continuously monitors operating parameters such as inlet air temperature, pressure, flow rate, and discharge conditions. Based on this feedback, the control system automatically adjusts the speed of the direct-drive compression assemblies to maintain optimal operating points. The feedback mechanism enables real-time optimization of energy consumption and operational efficiency, allowing the system to adapt to changing conditions without manual intervention and to recover from off-optimal conditions automatically.
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 enhances operational efficiency by allowing for variable discharge pressures and improved turndown capabilities, accommodating changes in operating conditions without sacrificing overall plant efficiency.
Implementation Method 1
compressing at least a portion of the incoming feed air stream in a lower pressure single stage or multi-stage compressor of a common air compression train
Implementation Method 2
purifying the further compressed feed air stream to remove impurities
Data Source
AI summary
A method for compression of an incoming feed air stream using at least two variable speed compressor drive assemblies controlled in tandem is provided. The first variable speed drive assembly drives at least one compression stage in the lower pressure compressor unit driven while the second variable speed drive assembly drives higher pressure compression stage disposed either in the common air compression train or the split functional compression train of the air separation plant. The first and second variable speed drive assemblies are preferably high speed, variable speed electric motor assemblies each having a motor body, a motor housing, and a motor shaft with one or more impellers directly and rigidly coupled to the motor shaft via a sacrificial rigid shaft coupling.