Multistage Cooling Plant With Intermediate Heat Exchanger Pressure Control
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Solution Overview
Problem
Existing multistage cooling plants face issues with high complexity, cost, and reduced efficiency in managing pressure control during shutdown periods, particularly with hazardous fluids like hydrocarbons, requiring complex and expensive configurations that complicate safety and installation.
Innovation Solution
A pressure-controlled multistage cooling plant design that uses a safety compressor and intermediate heat exchanger to manage pressure by feeding a refrigerant fluid from the high stage to the low stage, reducing pressure without the need for a complex receiver or hazardous fluid connections, and allowing the high stage circuit to be contained in a single environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small refrigerator system is used to cool the low stage cooling fluid when pressure reaches maximum threshold, then the pressure is reduced to safety values, but the system complexity and cost increase significantly
Solution Approach 1:
The invention extracts the pressure control function from the low stage system and relocates it to the high stage system. The high stage compressor and heat exchanger are used to remove excess pressure from the low stage receiver, eliminating the need for a separate refrigerator system in the low stage.
Solution Approach 2:
The high stage cooling system is made multi-functional by enabling it to perform both its primary cooling function and the secondary function of pressure control for the low stage. The high stage compressor and heat exchanger serve dual purposes: cooling the high stage fluid and removing excess pressure from the low stage receiver.
2Reliability
If the high stage plant is connected to the low stage storage tank for fluid expansion cooling, then pressure control is achieved, but installation complexity and safety requirements increase due to hazardous fluid connections
Solution Approach 1:
The invention segments the two cooling stages into completely separate environments. The high stage system operates in one environment while the low stage system operates in another, with no physical connections between them. Pressure control is achieved through thermal coupling via the shared heat exchanger rather than direct fluid connections.
Solution Approach 2:
The heat exchanger serves as an intermediary between the high stage and low stage systems. Instead of directly connecting the hazardous low stage fluid to the high stage system, the heat exchanger mediates the thermal interaction, allowing pressure control without direct fluid contact or complex piping connections.
3Reliability
If the low stage receiver is internally provided with an exchanger for cooling, then pressure control is achieved, but the receiver becomes complicated and expensive with additional connections
Solution Approach 1:
The invention extracts the heat exchanger from the low stage receiver and relocates it to the high stage system. The low stage receiver becomes a simple storage vessel without internal exchangers or complex connections, while the high stage system contains the heat exchanger that performs both high stage cooling and low stage pressure control.
4Reliability
If the main compressor of the high stage is used continuously for pressure control, then pressure management is effective, but compressor wear and energy consumption increase
Solution Approach 1:
The high stage compressor operates periodically rather than continuously for pressure control. The system uses the compressor only when the low stage receiver pressure exceeds the threshold, allowing the compressor to rest during normal operation and reducing overall wear and energy consumption while maintaining effective pressure management.
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
The solution provides a simple, reliable, and cost-effective pressure control system that reduces wear on the main compressor and energy consumption while ensuring safety and efficient operation, even with hazardous fluids, by using a safety compressor and intermediate heat exchanger to manage pressure in the low stage.
Implementation Method 1
at least a first duct (15) of an intermediate heat exchanger means (18)
Implementation Method 2
to expand the cooling fluid of the high stage in a first duct (15) of an intermediate heat exchanger means (18) having a second duct (24) of the low stage inserted
Data Source
Figure 1
Figure 2
AI summary
A pressure controlled multistage cooling plant has a high stage (3) comprising at least a set of first compressors (5), a set of first condensers (7), at least a first receiver means (11) and a first duct (15) of an intermediate heat exchanger means (18) mutually connected to form the high stage refrigeration circuit. Said plant (1) is further provided with a low stage (20) comprising at least a set of second compressors (22), a second duct (24) of the intermediate heat exchanger means (18), at least a second receiver means (26), a set of low stage user apparatus (28) mutually connected to form the low stage refrigeration circuit. Said plant comprises pressure sensor means (30) assigned to detect the pressure of the fluid of the low stage (20) and connected to control means assigned to activate a feeding means (31) when said pressure of the fluid of the idle low stage (20) reaches or exceeds a predetermined threshold value. Said feeding means (31) are activated and connected to a duct of the intermediate heat exchanger means (18) to feed in said duct a cooling fluid for cooling the fluid of the low stage (20) in a condition of activation of said feeding means (31). Said duct of the intermediate heat exchanger means (18) that can be connected to the feeding means (31) consists of the first duct (15) of the intermediate heat exchanger means (18) and the cooling fluid feed by the feeding means (31) consists of the fluid of the high stage (3).