Boiler feedwater consists of makeup water plus condensed steam. For makeup, many plants utilize raw water that requires pretreatment with some combination of clarifiers, sand filters and mixed media filters. The resulting water then undergoes additional treatment through reverse osmosis membranes, demineralizers, electrodeionizers, ultrafiltration or other systems. The final low conductivity ultrapure water provides the levels needed for optimal boiler performance.
Utilization of pure condensate instead of makeup water provides tremendous value to the plant by minimizing use of chemicals and energy to produce makeup water. However, condensate inevitably involves the risk of steam cycle contamination from condenser leaks. Returning poor condensate to a boiler may result in reduced heat transfer efficiency, increased blowdown, and associated water, energy and chemical costs. Condensate monitoring may allow early detection of condenser leaks and provides information on total boiler water treatment performance.
Regardless of the water source, problems in water treatment will propagate through the entire steam cycle if not corrected. Maintaining and troubleshooting the equipment utilized to process raw water or condensate constitutes a critical step in the cycle.
SOURCE: Hach Company