Plant & Works Engineering September 2022 Issue

T he UK is in the midst of an energy crises and, while many manufacturers have purchased energy supplies in advance, as these contracts end, they will have to renegotiate and secure energy supplies for the coming years during this high price period. Concurrently, industry is tasked with bringing all GHG emissions to net zero by 2050. These two key challenges have resulted in a focus on developing and employing mature energy efficiency and decarbonisation technologies. When it comes to heat raising systems, it’s undeniable that these use particularly large quantities of energy, but manufacturers of these systems have invested considerable R&D resources into improving their energy efficiency and emissions. Steam generation Fire tube and coil type steam generators produce ‘dry’ saturated steam to maximise the delivery of heat to the user. They are ideal for use where both direct and indirect heating are required simultaneously and where heat transfer at a constant temperature is required. Both types operate along the same basic principles in that water is confined in a restricted space and is heated by burning a fuel source. The energy of combustion is transferred from the flame to the water by radiation and conduction, heating the water and ultimately raising steam. Modern steam generators have progressed considerably and now include a very accurately controlled burner which creates a defined heat input to a double coil of steel tube through which a precise quantity of feed water is pumped. Only a small amount of excess water is fed into the coil to provide the correct operating conditions at all times and a steam/water separator is usually incorporated at the coil outlet to ensure dry steam is provided to the process. Using this method, steam generators consume less energy as they only fire on demand for steam from the process, and can be very quickly brought up to working pressure when steam is required. This means the bare minimum of standing losses resulting in reduced overall emissions. Developments have also been made to improve overall efficiency and control of tube boilers and burners, which also means reduced fuel demand, better control of the burner, and improved emissions. At the Real Petfood Company’s manufacturing facility in Bodelwyddan, north east Wales, a Babcock Wanson BWD40 Fire Tube Boiler is being used to heat retort cookers and mixing vessels for baked pet treats. It was chosen due to its high efficiency, long-life and low-cost maintenance. Efficiency comes as a result of the optimised matching of the boiler shell and the burner, along with advanced burner head geometry which provides stable combustion with near constant efficiency throughout the complete burner modulating range. Using Babcock Wanson’s latest micro-modulation Optimo burner, the BWD40 has emission rates of less than 100mg/Nm3 NOx throughout Process, Controls & Plant Focus on: Process Heating & Cooling The drive towards energy efficient, decarbonised technology 28 | Plant & Works Engineering www.pwemag.co.uk September 2022 Etienne Fourie, Technical Sales Manager, Babcock Wanson, looks at the drive towards energy efficient, decarbonised technology.