In this article, following its recent launch of the SCOPE sequencing controller, Carl Knight – managing director of process steam and heat transfer specialist Fulton – takes a look at boiler sequencing control systems and how these intelligent controllers can optimise steam boiler installations to ensure energy efficient operation and improve boiler longevity.

Numerous processing facilities operate multiple steam boilers to meet the demands of their on-site processing equipment. Some sites operate a number of boilers to provide redundancy or reliability, others because space considerations mean multiple boilers are the preferred solution to a single, much larger boiler. However, if the steam boilers in facilities with multiple units are not optimised for efficiency, then the potential for any energy savings is not being utilised to its fullest.

The use of intelligent sequencing system can provide redundancy and reliability and also offer significant energy savings by automating start-up and shut-down procedures; controlling and optimising main steam header pressure or temperature; ensuring steam supply is controlled precisely for the required process; and balancing the load distribution across the boilers, thus eliminating extensive losses from repeated start/stop cycling of burners as much as is feasibly possible.

Sequencing should be about more than just simply on/off or start-up control. An intelligent sequencing system should also consider steam system load conditions and match this to the most efficient combination of boiler capacity according to the process requirements.

Load response and start-up times are also factors. For example, a boiler sequencing control system should be capable of knowing when running too many or too few boilers is having a negative effect on efficiency and productivity. It should be able to monitor and pre-emptively predict a sudden surge in demand and boiler utilisation by monitoring existing boiler demands, system pressures and flow rates; therefore starting/stopping boilers appropriately depending on the process demands.

There are also factors including what happens in the case of boiler failure, sudden high steam loads and even lack of boiler availability due to servicing. A good sequencing system should take all of these factors into consideration and then manage the boiler operation automatically. With the result being that the end user doesn’t notice that a second or third boiler had to be started, because the machine they are working on has just started a high steam demanding stage during its production process.

Additionally, benefits that can be achieved through the installation of an intelligent boiler sequencing system, which can include complete automation for start-up and shutdown of the boilers; better control of the main steam header pressure, leading to more consistent pressure and steam dryness fractions, vitally important factors for sterilisation processes and accurate heat transfer rates; precisely-controlled process steam or hot water supplies; boilers operating at main header pressure or temperature not maximum pressure or temperature; improved boiler longevity thanks to redundancy; and improved fuel savings through eliminating idle time at low fire.

But what about the future of boiler sequencing and the development of intelligent control systems using Cloud? 

Many processing facilities operate 24/7 so, to keep these facilities running consistently and efficiently, immediate action is often required and/or expected from the boiler manufacturer. By accessing its SCOPE intelligent sequencing system via Cloud based systems, Fulton is already looking to incorporate remote accessibility for diagnostic- and service-related issues; and providing remote data for system improvements, which can be accessed by specialist engineers for diagnostics and clients for data review.

Fulton is also looking at the ability to perform certain maintenance procedures or service steam boilers remotely, no matter where in the world they are installed. This would help to reduce the environmental impact and costs associated with travel to/from site, savings that can be passed onto the client.

The future will therefore offer simple sequencing control of multiple boiler installations or a full boiler-house energy management system, accessible remotely by the manufacturer and client alike, to provide an efficient solution for everyone.

For additional information about Fulton, please visit www.fulton.co.uk.