Blowdown is used to remove suspended solids present in the system. These solids are caused by feedwater contamination or by internal chemical treatment precipitates.
By minimizing boiler blowdown, you will save water and energy.
In high quality boiler water, levels of suspended and dissolved solids are down to a minimum. This will minimize blowdown volume and hereby reduce energy loss, as the temperature of the blowdown liquid is the same as the steam generated in the boiler. Lower blowdown rate will also reduce makeup water and chemical use, saving you money and water.
For example, the blowdown can range from less than 1% when an extremely high-quality feedwater is available and then can be greater than 20% in a critical system with poor-quality feedwater.
The blowdown rate required for a particular boiler depends on the boiler design, the operating conditions, and the feedwater contaminant levels. Sometimes, certain boilers may require lower than normal blowdown levels due to unusual boiler design or operating criteria or an exceptionally pure feedwater requirement.
There are several factors which can contribute to the reduction of energy consumption on the water side of steam boilers;
Blowdown rate is often the most poorly controlled variable of an internal treatment program, and as outlines above, reduction in boiler water blowdown can result in significant fuel and water savings.
Heat recovery is used frequently to reduce energy losses that result from boiler water blowdown
Scale Reduction via pre water treatment
Heat transfer is inhibited by scale formation on internal surfaces. Scale reduction through proper pre treatment and internal chemical treatment results in cleaner internal surfaces for more efficient heat transfer and resultant energy savings.
It is not necessary to know chemistry to appreciate the fundamentals of water treatment. Good water treatment practice is dependent on a suitable treatment regime for the whole system; from the cold feed to the returning condensate.
The purpose of boiler water treatment is to protect the boiler and steam system against corrosion and scale formation and help maintain steam purity and quality. Poor quality feedwater will lead to poor quality steam, increase energy costs, reduce efficiency, reduce plant life and the boiler will be unreliable and unsafe.
Without effective water treatment, you will almost certainly be spending more than you need to on energy, water and effluent charges.
AquaChem are specialists in steam boiler water treatment and have a comprehensive range of boiler water treatment chemicals, dosing systems and water softeners.
For more detail on the principles of boiler water treatment call Aquachem on 018 252 775 or visit our website aquachem.ie