When many plants were built years ago, they were instrumented to provide what was required for safely manage the process. As time has passed, the requirements are far greater for efficiency, reliability and regulatory demands.In a Power Engineering International article, Modernizing old plants to meet new demands, Emerson’s Jonas Berge describes how power plants are being modernized with a second layer of automation to meet the challenges in increasing reliability, energy efficiency and productivity, and health, safety and environmental (HS&E) regulations.
Much of this second layer of automation, or pervasive sensing, is wireless and non-intrusive—which means that it can be easily deployed. Jonas lists a number of applications that have already been deployed in power plants including:
…analyzing thermal efficiency, detecting steam trap and relief valve failure, improving mercury removal from flue gas, heat recovery steam generator (HRSG) outage planning, detecting water intake filter plugging, managing fuel inventory, preventing coal stack fires, improving fire-fighting system integrity, valve diagnostics, pump and fan condition monitoring, water balancing, leak detection, wastewater pond selenium reduction, ash landfill leachate pumping, and more.
Jonas provides examples in the areas of improved availability, efficiency, HS&E compliance and productivity.
For improved availability, he notes:
Maintenance costs can be lowered by reducing preventive maintenance and scheduled downtime and moving from reactive repairs to predictive maintenance. Moreover, by knowing which equipment needs overhaul and which does not, plants may be able to schedule their outages more effectively, extending the time between outages and making them shorter.
This is accomplished with:
Additional wireless sensors for equipment pressures, temperature, flow, fluid levels, position, pH and conductivity provide data on operating process and ambient conditions, allowing other problems like fouling, scaling, leaks, etc to be detected. Combining highly instrumented assets with analytic software creates an early warning system that can be easily understood and does not require an expert analyst to interpret.
Jonas shared many examples of how this pervasive sensing is delivering results:
A power plant in South Korea had issues with cooling water and lube oil pump failure caused by vibration. They had the same problem on their draft fans. Wireless vibration transmitters were deployed to capture developing vibration problems before they led to failure.
Power plant efficiency is measured by the heat rate. Replacing manual inspections to detect water leaks, steam leaks, cold and hot air leaks, plugged filters and scaling on tubes with pervasive sensing devices:
…enables the performance team to detect leaks and inefficiencies much sooner.
As a result, heat rate can be improved and sustained over longer periods of time. The consumption of treated water, compressed air, gas, electricity, and steam (WAGES) around the power station can also be reduced.
Read the article for examples of how power producers improved efficiency as well as ways to improve HS&E compliance and improved productivity. Jonas concludes:
Not designing a new power plant or modernizing an existing one for maintainability, performance monitoring, emission monitoring and situational awareness sets the stage for gradually worsening heat rates and a reactive maintenance and environmental culture. Therefore, make sure budgets for maintenance & reliability, performance, HS&E, and productivity are incorporated into the project prior to kickoff and for the coming years. Work with an expert who is well-versed in pervasive sensing solutions to audit your existing plant or new plant design to identify which solutions are recommended and to get an estimate of the cost, potential savings and ROI for your plant.