Cryogenic Compressor Startup Cooling to Minimize Process Gas Venting
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Solution Overview
Problem
Cryogenic compressors vent process fluid during transient cool-down periods, leading to product loss and increased costs, as existing systems are not designed to operate effectively during this phase without auxiliary cooling.
Innovation Solution
A multi-stage compressor system with inter-stage heat exchangers that circulate a coolant through heat exchangers and cooling jackets to manage fluid temperature during startup, allowing continuous operation without venting by routing fluid through heat exchangers or bypass conduits based on temperature criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the compressor is designed to operate during transient cool-down period, then product loss is reduced, but the system complexity increases
Solution Approach 1:
The system is divided into multiple functional segments: compression stages, interstage heat exchangers, bypass conduits, and control systems. Each segment operates semi-independently, allowing the compressor to handle both cryogenic and ambient temperature fluids through different pathways, thereby reducing product loss during startup without requiring a completely new system design
Solution Approach 2:
The compressor system is designed with multi-functionality to handle both cryogenic process fluid compression and ambient temperature fluid compression through the same basic infrastructure. The interstage heat exchangers and bypass conduits enable the system to adapt its operation mode based on temperature conditions, eliminating the need for separate auxiliary cooling equipment
2Loss of substance
If auxiliary cooling equipment is added to prevent venting during startup, then product loss is reduced, but the device complexity and cost increase
Solution Approach 1:
The compressor system serves itself during the cool-down period by using its own compression capability to circulate and compress the ambient temperature process fluid. The interstage heat exchangers utilize the compression process itself to gradually cool the system components, eliminating the need for external auxiliary cooling equipment while preventing product venting
3Productivity
If the compressor operates with ambient temperature fluid during startup, then the system can run without venting, but the fluid temperature must be managed
Solution Approach 1:
The control system continuously monitors the temperature of the process fluid and the state of system components, dynamically adjusting the operation mode. Based on feedback signals, the controller determines when to route fluid through bypass conduits for ambient temperature compression and when to activate interstage heat exchangers for cooling, enabling continuous operation while maintaining appropriate temperature management
Solution Approach 2:
The system dynamically transitions between different operational modes during startup: initially compressing ambient temperature fluid through bypass conduits, then gradually incorporating interstage cooling as components cool down, and finally operating in full cryogenic mode. This dynamic adaptation allows continuous operation while managing fluid temperature according to real-time system conditions
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
Enables the compressor to operate during the transient cool-down period without venting the process fluid, reducing product loss and associated costs, and accommodating cryogenic fluids without auxiliary cooling equipment.
Implementation Method 1
an interstage heat exchanger between each compression stage through which the process fluid flows
Implementation Method 2
a first cooling jacket to provide cooling of the fluid in the first compression stage via heat exchange with the first coolant
Data Source
AI summary
Systems and methods are provided for compressing a cryogenic fluid using a multi-stage compressor. Coolant in a first coolant loop cools cooling jackets of the compression stages and/or inter-stage heat exchangers and warms a pre-compression heat exchanger. The temperature of the coolant in the first heat exchanger is moderated by ambient-air heat exchange. The process fluid is electively cooled by one of the interstage heat exchangers after each of the compression stage if the temperature of the process fluid is above a temperature criterion. This enables the system to operate through a transient period (cool down period) without venting process fluid. The interstage heat exchangers are preferably bypassed when the system reaches steady-state operating temperature.