Following the steps below will help you improve the way your process control system operates and reduce your energy costs.
1. Investigate the current system
Monitor your system's performance and walk around your site looking for signs of poor control. These include inconsistencies in product quality, variations in the energy used per unit of product, controls set to manual instead of automatic, and production upsets.
2. Check instruments and regulators
Ensure that all your existing instruments and regulators have been correctly installed and are working well. You should repair any faulty equipment, fix 'sticky' valves and check that measurement devices like sensors and probes have been properly installed, replacing them if necessary.
3. Make sure controls are working well
Check that control loops are not always set to manual and make sure operators are aware that working in automatic mode is much more efficient. Review control loops to check they're correctly configured and tuned and adjust controllers to minimise time delays and dead time.
4. Identify improvements in control
Draw up a list to show where you could save energy by improving your systems control. You should prioritise low-cost actions and enhancements and think about when to start larger projects. Identify the capital cost and payback period for each and put together an action plan for implementation.
5. Plan for implementation
Put together the business case for the implementation of your plan. This should include a feasibility study of costs and savings, a detailed risks/benefits assessment and information about the project and the project team. A pilot study could help decision-makers to give support to the project.
6. Take action and improve controls
Ensure that all new control equipment is installed and calibrated properly. You should train operators to use the new systems and how to deal with unexpected performance after the changes have been made. You should also set new energy consumption targets and draw up a preventive maintenance schedule to keep controls running well and run a campaign to increase awareness of the new systems and changes that have been made among your staff.
7. Monitor performance
Set up a regular system of checks to identify any areas of poor control as early as possible, perhaps when investigating your current system. This should include reviewing operator logs for symptoms of poor control, setting performance targets and comparing them with independent benchmarks, and reviewing targets regularly to make sure they're appropriate.