Double block and bleed valve systems should be used wherever any regenerant chemicals are introduced into the water system to protect against damage due to valve failure. Poor water treatment system training and operation. If operators are not properly trained and cognizant of the importance of operating these often-sophisticated systems, they might be responsible for pumping concentrated acid and caustic into the boiler. A less likely problem might be improperly carrying out the regeneration of water treatment equipment, such as improper rinsing of residual acid and caustic. Undetected contamination of condensate returns is another common problem, which leads to boiler feedwater contamination.
Contaminants can vary from metals such as copper and iron, to oils and process chemicals.
Heavy metal contamination is usually a function of the materials of construction of the process equipment and the condensate system. Oils and process chemicals are generally introduced into the condensate system due to process equipment failures or corrosion-caused leaks in equipment, such as heat exchangers, pump and gland seals, etc. The biggest risk associated with condensate system contamination is a catastrophic failure of a piece of process equipment, which results in the introduction of significant quantities of undesirable chemicals or compounds into the boiler. For this reason, prudent boiler operations should include continuous monitoring of the quality of condensate being returned from the process with automatic dump capability in case of contamination. Another problem that sometimes causes severe boiler fouling is the introduction of ion exchange resin into the boiler feedwater system.