Combustion specialist improves boiler efficiency for European chemical processing plant

19-May-2022

Martin Thirsk, Managing Director of Energy Technology & Control — global leaders in the design and development of combustion controls and burner control technology — explains how the company’s innovate Plant Master mode empowered a European chemical processing plant to dramatically improve the efficiency of its boiler set-up

Energy Technology & Control is a global leader in combustion controls and technology. Our skilled team of engineers have more than 200 years of combined experience in designing and manufacturing state-of-the-art burner technology and equipment.

A European chemical processing plant recently contacted us seeking to improve the efficiency of its boiler set-up. The plant utilises 10 boilers to provide enough steam in both the processes of making the chemicals and the operation of the plant itself. In this article, we analyse how a sequencing system can be used to analyse boiler results and improve efficiency.

Boiler efficiency versus factory demand

When multiple boilers use a common steam header, each boiler will be working separately to meet the overall demands of the business. Without a sequencing system, this can result in one or two boilers working flat out while others idle. By incorporating a sequencing system — such at the Plant Master mode available on our ETC6000 — it allows the system to accurately ascertain the capacity of the entire boiler set-up.

By comparing this with the most efficient operating point for the individual boilers, it can then ensure that each boiler is run at its highest level of efficiency to meet the factory’s current power requirement.

This allows engineers to view all boilers as one system, providing input into the steam generation process. We connect a CANBus sensor to a local ETC6000 controller — the CANBus sensor is connected directly to the plant master — to measure the steam pressure.

The Plant Master interface allows the CANBus sensor to be designated as the sensor input and power supply (to monitor the header pressure or temperature for the entire system). The engineer will enter details regarding high fire, low fire and the best modulation; the Plant Master will then deduct the most efficient range for each boiler.

The costs of inefficiency

Typically, boiler efficiency peaks at around 75% modulation but all boilers are different. Once correctly set up, the system will try to keep each boiler at its most efficient modulation rate … but will modulate them past this point if demand requires. A well-modulated sequencing system enables the overall system to better match its output to demand, meaning that the processes that rely on this are better served.

A factory with an inefficient boiler set-up can suffer in several ways. If the boilers are working too hard, they will produce extra heat that, if not used, ends up going to waste; conversely, if the heat produced doesn’t meet demand, the cooking process is slower … which adversely affects the bottom line.

A decrease in efficiency at full output typically occurs because of the increased heat losses accrued. Conversely, boiler losses can also increase at lower modulation rates; this occurs for a variety of reasons, not least because although modulation rates can be reduced, the physical size of the equipment remains constant.

Improving the on/off strategy with intelligent sequencing will lead to less boiler cycling, increasing the overall efficiency of the set-up and reducing the wear on the boiler and system components. Less boiler cycling also increases efficiency of the overall system because boiler purging at start-up leads to heat losses.

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