Boiler water treatments
Steam generation and or hot water has always been a basic energy transfer medium for all kinds of different industries . With the continued increase of energy costs, industry has over the years looked for efficiency improvements both in boiler design, pre- and chemical treatment.
The pretreatment section of the boiler plant is usually designed to remove undesired materials /elements from the make –up water, that may have an influence on the corrosion, deposition and the total water consumption of the boiler plant.
The design of the external pretreatment will heavily depend on the size of the boiler, the purpose of the steam / hot water and the steam pressure. The external treatment may vary from a simple softener to a full demineralising or a RO plant, combined with a deaerator to remove oxygen.
Again depending on the size and purpose, a boiler may be equipped with an economiser and or a superheater. The economiser is simply a heat exchanger using hot stack gasses to preheat the boiler water and recover some of the heat otherwise leaving the boiler via the stack.
Superheaters are typically found in high pressure boilers and as superheated steam contains more energy then saturated steam, superheated steam is mainly used to drive turbines. Boilers equiped with superheaters are more critical and require extensive external treatment.
Condensate return can be an important share of the total make up water for the boiler and may require specific external treatment before it can be reused. The external treatment for the condensate return will depend on the contamination from the process and or the corrosion products that occurs in the return lines.
Blowdown by definition is the removal of a relative smalll quantity of the concentrated boilerwater to maintain the desired dissolved and suspended solids in the boiler. Each boiler has its own specific levels of suspended and dissolved solids it can tolerate , depending on the boiler design , pressure and steam use.
Each boiler, no matter how much external treatment takes place, are suspect to corrosion and or deposition combined with after boiler corrosion due to dissolved gasses and or carryover. A balanced chemical treatment regime is required to protect the (pre-) boiler and the after boiler section to ensure corrosion and deposition preventation and create optimum efficíency and reduce energy costs.
R&R Watertechnology B.V.
2645 LW Delfgauw
Tel: +31 15 2033810