Compressor Control System:

For Seafood Processing Industry

Home » Compressor Control System | Seafood Processing Industry

CASE STUDY:

End User:

Confidential

Project Scope

Comprehensive Supply, Installation, Testing, and Commissioning (SITC) of Programmable Logic Controllers (PLC), Human-Machine Interfaces (HMI), and Variable Frequency Drives (VFD) for Advanced Compressor Management Control in the Seafood Processing Industry

1. Introduction

This document delineates the comprehensive scope for the Supply, Installation, Testing, and Commissioning (SITC) of Programmable Logic Controllers (PLC), Human-Machine Interfaces (HMI), and Variable Frequency Drives (VFD) within a sophisticated compressor management control system tailored for the seafood processing industry. The goal is to enhance operational efficiency, reduce energy consumption, and mitigate issues related to unpredictable compressor malfunctions.

2. Background

The seafood processing industry relies heavily on refrigeration systems, which include multiple compressor units designed to maintain optimal temperatures for product quality and safety. Key challenges faced by this industry include:

Unpredictable Machine Trips: Unexpected compressor shutdowns causing operational disruptions and potential product quality issues.
High Energy Consumption: Inefficient compressor operation leading to elevated energy costs and increased environmental impact.

In response to these challenges, there is a pressing need for a Variable Frequency Drive (VFD)-based control solution, coupled with advanced monitoring through a Human-Machine Interface (HMI). This solution will facilitate precise control over compressor operations, enabling real-time monitoring and adjustment to enhance system reliability and efficiency.

3. System Description

3.1. Control System Overview

The proposed compressor management control system integrates several advanced components and technologies:

Programmable Logic Controller (PLC):
- Function: Acts as the central processing unit for the control system, managing input from various sensors and controlling output to the Variable Frequency Drive (VFD) and other system components.
- Capabilities: Provides sophisticated logic control, manages interlocks, and monitors system parameters.
Variable Frequency Drive (VFD):
- Function: Regulates the speed of the compressor motor based on real-time data, adjusting compressor output to match temperature demands.
- Capabilities: Enables energy-efficient operation by varying motor speed, reducing energy consumption compared to constant-speed compressors.
Human-Machine Interface (HMI):
- Function: Serves as the user interface for system interaction, allowing operators to view real-time data, adjust set points, and monitor system performance.
- Capabilities: Provides intuitive access to system parameters, alarms, and operational data, enhancing user control and decision-making.

3.2. Control Algorithm and Temperature Regulation

Suction Pressure-Based PID Control Algorithm:
- Purpose: Maintains a stable temperature within the storage area by adjusting compressor speed based on suction pressure.
- Mechanism: A pressure transmitter installed in the compressor suction line measures the suction pressure, which correlates with the storage temperature. The pressure data is fed to the PLC.
Feedback and Control:
- Feedback Loop: The PLC processes the suction pressure data using a Proportional-Integral-Derivative (PID) control algorithm.
- Output Control: The PID output is used to modulate the compressor speed via the VFD, ensuring precise control over the refrigeration process to maintain the desired temperature.

3.3. System Integration and Monitoring

Pressure Transmitter:
- Function: Measures suction pressure and provides feedback to the PLC, ensuring accurate temperature control.
PLC System Integration:
- Components Monitored: Includes evaporator fan, oil pump, water chiller pump, refrigerant pump, oil pressure, suction pressure, and discharge pressure.
- Interlocks and Safeguards: Ensures safe operation by managing interlocks between critical components and preventing system malfunctions.
Defrosting Operation:
- Frequency: One hour per day.
- Purpose: Maintains the heat transfer capacity of the refrigeration system by periodically removing ice build-up.

4. Benefits and Outcomes

The implementation of this advanced compressor management control system provides several key benefits:

Enhanced Energy Efficiency:
- Optimization: The VFD enables the compressor to operate at varying speeds based on demand, reducing overall energy consumption.
- Cost Savings: Improved efficiency translates to lower operational costs and reduced environmental impact.
Extended Machine Life:
- Speed Control: By adjusting compressor speeds to match load demands, the system reduces mechanical stress and wear, thereby extending the lifespan of the equipment.
Improved System Utilization:
- Load Sharing: The VFD facilitates optimal utilization of compressor capacity through load sharing and precise speed control.
- Operational Efficiency: Enhanced control leads to fewer unexpected trips and smoother operation.
Enhanced Monitoring and Maintenance:
- Real-Time Data: The HMI provides immediate access to system performance data, enabling proactive maintenance and quick resolution of issues.
- Planned Maintenance: The system’s monitoring capabilities support planned maintenance schedules, reducing downtime and avoiding unscheduled disruptions.
Increased Safety:
- Auxiliary Interlocks: Integration of safety interlocks for auxiliary pumps and fans ensures reliable operation and enhances overall system safety.

5. Conclusion

The proposed SITC of PLC, HMI, and VFD systems represents a significant advancement in compressor management control for the seafood processing industry. By addressing key challenges such as unpredictable machine trips and high energy consumption, this solution will ensure improved operational efficiency, enhanced product quality, and a more sustainable and cost-effective refrigeration system.