The energy efficiency of steam systems can be improved by improving the efficiency of boilers and the reticulation system, point of use equipment and control systems used throughout the process.
There are many strategies to improve the efficiency by which steam is generated from boilers, such as:
- Identifying and repairing steam leaks and checking for gaps in insulation
- Optimising water treatment and total dissolved solids control to minimise blowdown
- Using steam traps and condensate return systems to reduce water loss by collecting condensation and returning it to the boiler1
- Investing in blowdown heat recovery as the blowdown water contains significant energy that can be recovered
- Investing in heat recovery more generally. For example, heat loss from flue gas usually represents the largest source of inefficiency. Flue gas can be redirected into either an economiser, which transfers heat to boiler input water, or a pre-heater, which transfers heat into the boiler input air.
- Investigating opportunities to reintroduce flash steam, which is created when blowdown occurs. If the blowdown stream is directed to a flash steam vessel, it can be recovered for low-pressure steam applications or sent to the de-aerator2
- Investing in boiler and burner management control systems
- Using digital combustion controls and oxygen trim
- Investing in variable speed drives for combustion air fans and coolant pumps
- Using solar thermal systems to pre-heat water before it enters the boiler
- Improving communication between the boiler room and operators.3
Some of these strategies are summarised in Figure 1.
Figure 1: Typical boiler losses for a shell boiler
Source: Carbon Trust (2012) Steam and high temperature hot water boilers
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