Technology

Blowdown heat recovery

Blowdown heat recovery
© alhim, image #104862150, 2017, source: Fotolia.com
Resources:
Energy
Sector:
All sectors
Investment cost:
High cost
Payback time:
8.2 Year(s)
Cost savings:
8777€ / Annual saving of € 8 777 (£ 8 052)
Resource type:
Heating
Resource saving:
Annual gas consumption reduced 268 415 kWh, 49 509 kg CO2 equivalent
Investment cost:
71940€ / € 71 940 (£ 66 000) for the project, based on blowdown volumes and temperatures
Assumptions taken in the presentation of the above performance indicators:

Installation of blowdown heat recovery works best where there is no heat recovery on blowdown at present; assumed top-up of steam-boiler of 18 450 m3 per annum with an 8 % blowdown loss; system efficiency of 70 % and 80 % heat recovery

On a daily or weekly basis, steam boilers blow down hot water from the boiler to avoid the formation of sludge.

Blowdown heat systems can recover much of this waste heat and reuse it. The system is made up of a flash vessel and a heat exchanger. It works best when blowdown is carried out continuously when boilers are operating over longer periods and levels of condensation recovery are relatively low.

These systems can potentially be used with any steam boiler but are unlikely to be effective when paired with boilers of below 1 000 kW. Specialists are best suited to assess the needs corresponding to specific blowdown quantities, and ensure the equipment is correctly installed and commissioned. 

Each blowdown waste-heat recovery project needs to be tailored to the quantity of blowdown being produced and the potential uses of the recovered heat. Maintenance is minimal upon installation.

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