Consequences of using "non-deaerated" demin water in condenser.
Consequences of using "non-deaerated" demin water in condenser.
(OP)
I have powerplant that uses demin water to make-up to the deaerator. What would be the conseqences, as far as water quality and metalurgy, for the water system if we were to make-up to the condenser/hotwell instead?





RE: Consequences of using "non-deaerated" demin water in condenser.
RE: Consequences of using "non-deaerated" demin water in condenser.
RE: Consequences of using "non-deaerated" demin water in condenser.
The boiler pH is usually on the alkaline side of the pH scale.
Sometimes in industrial facilities, the return condensate has a low pH from absorption of CO2. This is not normally the case in a power plant.
Some in the power industry advocate the use of a vacuum degasifier on the demin makeup to further minimize the introduction of oxygen into the system.
It is difficult to make any further comments without knowing more about the system.
RE: Consequences of using "non-deaerated" demin water in condenser.
The Graham DO2 system incorporates a vacuum DA with the condenser to eliminate the need for a pressurized DA in the cycle. Ecolaire makes a competing design. In combined cycle units eliminating the integral DA saves money in the HRSG and improves efficieny by offering the potential of a lower stack temperature. If the S in your fuel is very low this can improve project economics significantly.
RE: Consequences of using "non-deaerated" demin water in condenser.
If demin water is introduced at the condenser, it should be sprayed in at a location that ensures good deaeration and venting.
Air leakage into the system must generally be kept to a minimum because the ability of the condenser to eliminate oxygen is fixed by design. Most condenser tube bundles can meet guaranteed oxygen levels only over the upper range (50%) of the load.
Oxygen scavengers are also typically introduced at the discharge of the condensate pumps.
RE: Consequences of using "non-deaerated" demin water in condenser.
RE: Consequences of using "non-deaerated" demin water in condenser.