Thermal Oil Systems

Upgrading Critical Thermal Oil Systems Without Production Disruption

The Challenge Behind the Solution

The Challenge Behind the Solution

A leading chemical manufacturing company faced a significant challenge with their critical Thermal Oil System. The existing system was outdated and becoming increasingly unreliable, leading to frequent operational disruptions that threatened production schedules and product quality. They needed a solution that would modernise their system whilst ensuring perfect integration with their existing infrastructure. The dilemma was clear: how to upgrade mission-critical temperature control systems without causing major downtime in a continuous production environment where even brief interruptions could cost thousands of pounds per hour.

The Critical Issues

Production operations were hampered by four fundamental challenges:

  • Frequent System Failures: The ageing system was prone to unexpected breakdowns, causing unplanned downtime and disrupting carefully scheduled production runs
  • Imprecise Temperature Control: Existing temperature control mechanisms lacked the accuracy required for consistent product quality, leading to batch variations and potential product rejection
  • Escalating Maintenance Costs: The outdated system required increasingly frequent maintenance interventions, driving up operational costs and consuming valuable engineering resources
  • Integration Complexity: Upgrading components without disrupting existing infrastructure posed significant technical challenges and implementation risks

A Smarter Approach to Control

Rather than pursuing a disruptive wholesale replacement, our approach centred on collaborative modernisation that would deliver advanced capabilities whilst preserving operational continuity. Working closely with the production team, we developed a comprehensive solution strategy that addressed each challenge systematically.

Core Solution Elements:

  • Detailed assessment of existing infrastructure to identify critical integration points
  • Custom solution design tailored to specific operational requirements and constraints
  • Phased implementation approach to minimise production disruption
  • Comprehensive testing and validation procedures before system handover

Key System Components

Control Cabinet:

  • Enclosure: RS PRO Steel Wall Box, IP66 rated, 300mm x 1000mm x 800mm [DxHxW]
  • Environmental Protection: Designed for harsh industrial environments with full moisture and dust protection

PLC and I/O Systems:

  • Controller: SIMATIC S7-1200 with dual analogue input cards
  • Network Integration: Connected via Stratix 5700 industrial switch
  • Software Platform: Firmware version 4.4, programmed using Step7 TIA Portal version 16

Human Machine Interface:

  • Display: Siemens TP1200 Comfort HMI – 12″ colour touchscreen
  • Configuration: Developed using WinCC TIA Portal version 16 for intuitive operator control

Signal Conditioning:

  • Barriers: PR9106B2B modules providing 4-20mA signal repeating across 2 channels for analogue inputs
  • Protection: Intrinsic safety barriers for hazardous area compliance

Pricing Information:

  • Components and hardware: £28,000
  • Engineering and programming: £15,000
  • Installation and commissioning: £12,000
  • Total project cost: £55,000

How the System Functions

Heating Mode Operation: The system continuously monitors process temperature against operator-defined setpoints entered through the HMI touchscreen. Control valves modulate automatically to maintain precise temperature control, with the PLC calculating optimal valve positions based on real-time feedback from temperature sensors and system demand.

Cooling Mode Control: When cooling is required, the control system transitions automatically to cooling mode, modulating different valve combinations to achieve the desired temperature reduction. Manual override capabilities allow operators to take direct control of individual actuated valves when required for maintenance or emergency situations.

Emergency Cooling Sequence: In emergency situations, the system executes a predetermined sequence: closing thermal control valves TCV1004, TCV1002, and TCV-1003; opening emergency cooling valve TCV1003 and relief valves R1AV15, R1AV16, and R1AV17; and stopping the thermal oil pump to prevent damage and ensure personnel safety.

Temperature Control Logic: The advanced PLC continuously processes temperature feedback through precision analogue inputs, comparing actual temperatures against setpoints and adjusting control outputs using sophisticated PID control algorithms that maintain stability whilst responding quickly to process changes.

Key Technological Advantages

Precision Temperature Control: The modern control system delivers temperature accuracy within ±0.5°C compared to the previous system’s ±3°C variation. This precision ensures consistent product quality by eliminating the temperature fluctuations that previously caused batch-to-batch variations and quality issues.

Advanced Diagnostic Capabilities: The SIMATIC S7-1200 controller provides comprehensive system diagnostics that monitor valve positions, temperature sensor health, and communication status. These diagnostics enable predictive maintenance by alerting operators to potential issues before they cause system failures.

Intuitive Operator Interface: The 12″ colour HMI provides clear, graphical displays of system status, temperature trends, and alarm conditions. Operators can easily adjust setpoints, monitor system performance, and respond to operational requirements without extensive training on complex control procedures.

Robust Integration Architecture: The Stratix 5700 switch provides reliable network communication whilst allowing integration with existing plant networks and SCADA systems. This architecture ensures that the thermal oil system data can be accessed by maintenance management systems and production planning tools.

Frequently Asked Questions

How did you minimise production disruption during the modernisation project?

We implemented a carefully planned phased approach that allowed the existing system to continue operating whilst new components were installed and tested in parallel. The project began with extensive planning and system analysis to identify the optimal changeover sequence. We pre-built and pre-tested the entire control cabinet off-site, including full simulation testing of all control logic. The actual changeover was scheduled during a planned maintenance window and completed within a single weekend shutdown. Critical components were installed with temporary bypass capabilities, allowing us to revert to the original system if any unexpected issues arose. This approach reduced the actual production impact to just 18 hours compared to the several weeks that would have been required for a traditional replacement approach.

What specific improvements in temperature control accuracy were achieved?

The modernised system delivers temperature control accuracy within ±0.5°C compared to the previous system’s ±3°C variation. This six-fold improvement in precision was achieved through several technical enhancements: higher-resolution analogue input cards that provide 16-bit temperature measurement accuracy, advanced PID control algorithms that respond more quickly to process disturbances, and faster control loop execution times in the modern PLC. The improved accuracy has eliminated the temperature variations that previously caused product quality issues, reducing batch rejection rates from 8% to less than 1%. Additionally, the consistent temperature control has allowed the production team to operate closer to optimal process conditions, improving both product quality and energy efficiency.

How does the new system integrate with existing plant infrastructure and future expansion plans?

The system was designed with comprehensive integration capabilities using standard industrial protocols. The Stratix 5700 switch connects to the existing plant network via Ethernet/IP, allowing seamless data exchange with the facility’s SCADA system and maintenance management software. Temperature data, alarm conditions, and system status information are automatically shared with the plant’s central monitoring systems. For future expansion, the control cabinet includes spare I/O capacity and additional network ports. The modular design of the SIMATIC S7-1200 system allows easy addition of extra analogue and digital I/O modules without requiring controller replacement. The HMI screen configuration can be easily modified to accommodate additional process displays or control functions as production requirements evolve.

What ongoing maintenance and support requirements does the modernised system have?

The modern system significantly reduces maintenance requirements compared to the previous installation. Routine maintenance consists of quarterly calibration checks of temperature sensors, annual backup of PLC programs and HMI configurations, and periodic cleaning of the HMI touchscreen. The advanced diagnostics continuously monitor system health and provide early warning of any component degradation. We provide comprehensive maintenance training for plant personnel and offer annual service contracts that include preventive maintenance, software updates, and priority technical support. Remote diagnostic capabilities allow many issues to be resolved without site visits, and the modular component design means that any required replacements can typically be completed within 2-4 hours rather than the days required with the previous system.

The Long-Term Impact

The successful modernisation of this thermal oil system demonstrates how critical process control infrastructure can be upgraded without disrupting ongoing operations. By taking a collaborative, phased approach that prioritised operational continuity alongside technological advancement, this project proves that companies can modernise legacy systems whilst maintaining production schedules and quality standards.

This project serves as a blueprint for how chemical manufacturing facilities can address ageing infrastructure challenges systematically, delivering immediate operational improvements whilst establishing a foundation for future process optimisation. The success of this modernisation approach has established new possibilities for upgrading other critical systems and serves as a model for infrastructure renewal projects across similar industrial applications.