2 replies to this topic

[rsk]

Sir
steam surface condensers in power plant generally require very high flow & low head application pumps. Advantage is taken of syphoning ( feasible with site conditions ) & pumps design head is generally reduced because of siphoning. Water boxes are installed with priming pumps , i have query whether any head loss are to considered in syphoning because of the priming pumps, also whether these priming pump meant for maintaing siphon by removing noncondensables because of release of dissolved gases.

[Adriaan]

When surface water is used for cooling a condensor you need to significantly over-design the cooling water pump capacity because of the reduced efficiency of the condensor due to fouling. A cleaning system (Taprogge or Excellent are common) for the condensor pipes is usually needed and that of course helps reduce fouling at a cost of a somewhat increased flow resistance. As there is usually a limit to the amount the cooling water can be heated up (in the Netherlands, for example, 10 'C temperature rise maximum and a cooling water outlet temperature limit of 30 'C or so) the cooling water flow has to be increased even more. Because condensor pipes are of a thin material to reduce thermal resistance and there is a vacuum condensor side the cooling water pressure is rather limited.

Prior to operation the condensor vacuum has to be established; when in operation the steam condensation produces the vacuum but a vacuum pump is indeed needed to maintain vacuum because of the dissolved gases etcetera (possible leaks and whatnot).

Finally you need condensate pumps than can be started with a VERY low NPSH (near vacuum in fact).

[rsk]

Sir i am sorry i was not able to put across the problem,

sir i am talking about cooling water side of condenser not steam side, please.