Reliability is absolutely essential to optimal boiler performance. In order to achieve the highest degree of dependability in a boiler it is important to identify and address the primary causes of boiler problems. One of the most common issues that can compromise a boiler is poor water quality.
The effect of water quality on boiler performance is a huge concern for plant owners and operators. Premature boiler failure often occurs as a result of poor or inconsistent feed water quality. Hard water elements in feed water are responsible for a number of issues:
Scale Build Up
The concentration of minerals in water, referred to as TDS (total dissolved solids), includes calcium, magnesium and silica. These elements in feed water can cause a dense scale to build up and harden on the surfaces within boiler equipment. Scale build up typically develops on the hottest surfaces and reduces flow through pipe which prevents the efficient transfer of heat.
Iron can be soluble or insoluble. It can clog valves and strainers and accumulate at the bottom of the boiler in the form of heavy sludge. Reducing iron in the water prevents corrosion and substantially increases the life of the boiler and associated equipment.
Oxygen Pitting in Boilers
Even in small concentrations, oxygen is highly corrosive when present in hot water. One of the most damaging kinds of oxygen corrosion is oxygen pitting, which involves concentrated pitting and corrosion in a very small area. Even though only a relatively small amount of corrosion and loss of metal has occurred, tube failure can happen.
Natural Water Bases
Bases such as bicarbonates, carbonates, hydroxides, silicates, borates, and phosphates in natural water breakdown to form carbon dioxide in steam. This is a major factor in the corrosion of condensate lines and contributes to foaming.
Water softeners, demineralizers or reverse osmosis systems can be used along or in combination to effective manage water issues and improve feed water quality. If water quality is a concern, selecting the right boiler type can also help. Fire tube boilers are a good choice if water hardness is an issue.