What are the bad effects of the impurities in the boiler feedwater?

If the impurities in the boiler feedwater are not dealt with properly, carryover of boiler water into the steam system can occur. This may lead to problems elsewhere in the steam system, such as:

1) Contamination of the surfaces of control valves - This will affect their operation and reduce their capacity.

2) Contamination of the heat transfer surfaces of process plant - This will increase thermal resistance, and reduce the effectiveness of heat transfer.

3) Restriction of steam trap orifices - This will reduce steam trap capacities, and ultimately lead to waterlogging of the plant, and reduced output.