Low Condenser Vacuum In 110MW Coal Based Thermal Power Plant

It's hard to visualized the system. Kindly post schematic diagrams of the cycle.

Stop all the leaks of non condensibles into your condenser.

Reduce your condenser temperature.

That's it.

Dear Mr.shad11,

You have not referred about Steam Condition. The Turbine is designed for a particular Heat Drop per Kg. of Steam, and if it is less the Heat rejected to the condenser will be more and hence vaccuum will be less. Pl. check this also.

Certainly Air Ingress in to the condenser could be another reason.

DHAYANANDHAN.S

Are you absolutely sure about those pressure units? 0.158 Kg(f)/cm² is 1580 Kg(f)/m², 2.25 psig, or 15.5 kPa. That would imply a saturation temperature of ~54 °C. But you show a much higher temperature on the gland seal, and maybe that is OK. Cooling water temperaturs seem OK to me. Condenser air ingress is the root cause most likely when needing more ejector capacity.

Your units of pressure, I am totally unused to, as these are not the standard SI (or English) units, but I understand them, and they seem OK to me. Your vacuum seems to be OK during roll-up, and that makes sense. It appears to me you are running too hot (too much) steam supply to the LP gland seals, as that temperature appears a bit high. Your cooling water is fine, but you may have a somewhat fouled condenser with this high difference between cooling water exit temperature and the hotwell temperature. There can be a number of reasons for this, but if this is a recent problem, you can rule out condenser design as root cause of air-binding of the tubes.

Assuming none of the condenser tubes are air-bound (the condenser can completely expell air), then you would expect good heat transfer. Your condenser is possibly bio-fouled or scaled heavily with mineral scale. More than likely, if there has recently been a turbine overhaul (last few months), and you cannot get "good" vacuum, and low residual gases such as oxygen, then there is a leak on a pipe somewhere, probably under the turbine where you least expect to find it.