Controlling refrigeration compression systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional control techniques for refrigerant compression systems often fail to provide fully automated stable operation, leading to issues like prime mover overload, compressor surging, and process downtime due to inadequate control of liquid refrigerant quench valves and anti-surge valves, especially during startup.
Innovation Solution
The implementation of suction temperature control circuits and a discharge temperature control circuit in a multi-stage refrigeration compression system, which determine quench flow demands based on setpoints and inlet temperatures to maintain optimal valve positions and minimize cooling requirements, allowing for fully automatic and coordinated control of quench valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control techniques are used for refrigerant compression systems, then the system can operate with simple control mechanisms, but the system fails to provide fully automated stable operation leading to prime mover overload, compressor surging, and process downtime
Solution Approach 1:
The patent implements multiple feedback control loops including suction temperature control circuits for each compression stage and a discharge temperature control circuit. These circuits continuously monitor temperatures and adjust quench valve positions accordingly, enabling fully automated stable operation and preventing prime mover overload and compressor surging
Solution Approach 2:
The control system automatically regulates quench valve positions based on real-time temperature measurements without requiring manual intervention. The suction temperature control circuits and discharge temperature control circuit self-adjust the quench fluid flow to maintain optimal operating conditions, achieving full automation during startup and transient operations
2Reliability
If quench valves are not properly controlled, then the system structure remains simple, but overheating occurs leading to process downtime and reduced availability
Solution Approach 1:
The patent divides the compression system into multiple stages, each with its own suction temperature control circuit and quench valve. This segmentation allows independent control of each stage's temperature, preventing overheating and improving availability while managing complexity through modular control architecture
Solution Approach 2:
The control system dynamically adjusts the quench fluid flow rate parameter based on measured suction temperatures and setpoints. By changing this parameter in response to temperature variations, the system prevents overheating and maintains reliable operation without requiring complex mechanical valve structures
3Temperature
If excessive quench fluid flow is used, then suction temperature is adequately controlled, but cooling demands and load on the system increase
Solution Approach 1:
The patent applies partial action by providing quench fluid flow only to compression stages where suction temperature exceeds the setpoint. Each suction temperature control circuit independently determines the required quench flow based on actual temperature measurements, avoiding excessive cooling and reducing overall system load and energy consumption
Solution Approach 2:
Different quench flow rates are applied to different compression stages based on their specific temperature conditions. The control system provides localized temperature control rather than uniform cooling, optimizing energy usage by matching quench fluid flow to actual cooling needs at each stage
4Extent of automation
If manual control of quench valves is used, then automation complexity is reduced, but fully automated stable operation during startup and transients cannot be achieved
Solution Approach 1:
Multiple feedback control loops continuously monitor suction temperatures at each compression stage and discharge temperature, automatically adjusting quench valve positions without manual intervention. This feedback mechanism enables fully automated stable operation during startup and transient conditions
Solution Approach 2:
The suction temperature control circuits are prepared and activated before compression operations begin, ensuring immediate automated control during startup. The control circuits establish optimal quench valve positions in advance, enabling smooth transitions and stable operation from the start of operation
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 improves safety, availability, and efficiency by preventing overheating, reducing downtime, and maintaining stable operation during startups and transients, while minimizing cooling demands and load on the system.
Implementation Method 1
a first quench valve operable to provide an adjustable flow of quench fluid into a first compression stage
Implementation Method 2
an expansion valve (also called a throttle valve) where its pressure abruptly decreases, causing flash evaporation and auto-refrigeration
Data Source
AI summary
A refrigerant compression system and method for controlling a refrigerant compression system are described. In some aspects, the refrigerant compression system includes a compressor system having a plurality of compression stages, a plurality of quench valves, a first suction temperature control circuit associated with a first quench valve, a second suction temperature control circuit associated a second quench valve, and a discharge temperature control circuit associated with a plurality of the quench valves. Quench valve settings are determined based on evaluation of one or more outputs from the suction temperature control circuits and the discharge temperature control circuit.