WATER SYSTEM MANAGEMENT
blowdown cycles result in varying reductions in the chemical treatment of the make-up water and less wastewater going to drain. The Carbon Trust has stated that based on a boiler operating on 10 bar of pressure, for every 1% that is saved in blowdown, there is a 0.2% fuel saving.
System optimisation
Make-up water treatment optimises the steam boiler and the processes and improves the boiler’s energy consumption. Fewer blowdown cycles directly correlate to a reduction in the chemical treatment of the make-up water, and ensure greater heat retention through the production of a higher quality steam. In summary, the benefits of make-up water treatment include: n Cost-saving benefits. n Consistent water quality. n Process optimisation. n Less frequent fouling and corrosion. n A reduction in chemical use. n Improved system longevity.
Water softeners are an integral part in the process of pre-treating the water that serves a boiler feed reverse osmosis system.
provide the best results. Prefacing the reverse osmosis system with a carbon vessel and ion exchange softening vessels ensures the longevity of the RO plant and the associated consumables, protecting various perishable consumable items such as multimedia filtration media and membranes from damage.
Reducing total dissolved solids (TDS) counts Boiler blowdowns are a known requirement for all steam boilers. There is a maximum threshold for passable concentration levels of dissolved solids and salts found within the water contained in the boiler’s chamber. The Carbon Trust says that the main disadvantage of blowdown is that typically 1% to 5% of the energy input to the boiler is lost.4
The purification process of reverse osmosis lowers the overall TDS count of the make-up water, and decreases the reliance on more traditional forms of treatment to protect boilers from internal scaling and corrosion (such as using phosphates and sulphites). It also tends to result in a reduction in the use of anti- corrosion agents and the amount of chemical conditioning that are required, thereby reducing costs further. All the aforementioned factors minimise the TDS count and prolong the period between required boiler blowdowns, while simultaneously ensuring and maintaining efficient boiler operation, resulting in energy savings. Fewer
74 Health Estate Journal November 2021
Typically, from an installer and service maintenance provider’s perspective, boiler feed RO installation has a payback period of between 12 and 24 months from the date of commissioning, providing cause for justifiable investment. Further guidance on the safe operation of boilers and best practices to meet all
Paul Godfrey
Paul Godfrey is the managing director and founder of Puretech Water Systems (UK). He began his professional career in the industrial chemistry industry at Ellis and Everard/Univar in the 1990s, specialising in the supply and troubleshooting of various chemicals to some of the UK’s largest blue chip companies. In 2000, he moved to the Water Treatment division of Ellis and Everard/Univar, where he focused heavily on water chemistry for the leisure market nationwide, and in 2005 joined an established reverse osmosis manufacturer which worked primarily in the healthcare sector, providing reverse osmosis solutions within Estates departments, and Endoscopy, Sterile Services, and laboratory settings. In 2012 he formed Puretech Water Systems (UK), a specialist reverse osmosis and water softening plant supplier. The business focuses heavily on providing water purification solutions for the healthcare sector, working with some of the UK’s largest NHS Trusts.
the current legislative standards can be found through The Combustion Engineering Association (CEA). The CEA guidance documents, BG01 – Guidance on Safe Operation of Steam Boilers,5 Blowdown Systems,6 Water Treatment,7
BG03 –
and BG04 – Boiler deal with separate
aspects of operational safety, and are useful aids in understanding what effect water and treatments will have.
hej
References 1 Health Technical Memorandum 07-04: Water management and water efficiency – best practice advice for the healthcare sector. 2013. Department of Health.
2 To become more water-efficient. NHS Property Services. [
https://tinyurl.com/238cw96t].
3 Water Treatment Handbook, 6th edn, Vol 1-2. Degremont. 1991 ISBN: 2950398413.
4 Heat recovery: A guide to key systems and applications. The Carbon Trust. [
https://tinyurl.com/hj9tswxj].
5 The Combustion Engineering Association (CEA) Guidance Document BG01 – Guidance on safe operation of steam boilers, 2019.
6 The Combustion Engineering Association (CEA) Guidance Document BG03 – Blowdown Systems, 2020.
7 The Combustion Engineering Association (CEA) Guidance Document BG04 – Boiler Water Treatment, 2020.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
