1 reply to this topic

[Art Montemayor]

bmicky:

First, let me ask if you are dealing with saturated water. The water temperature of 182 oC corresponds to a saturated pressure of 10.5 barA - and maybe this is what you meant. If it is saturated, then you should always describe it as such. There are other factors to consider when an engineer is dealing with the saturated liquid phase and it is good engineering to avoid assumptions, errors, & mistakes by introducing additional basic data later after work is done to arrive at an answer.

I'll assume the water has 4 oC of supercooling and go from there.

1) Your English is not all that good and what it literally says is that a block valve is located downstream of the heat exchanger. Therefore, if you shut that valve off, your centrifugal pump will increase its discharge pressure all the way to the "dead-head" pressure - which is readily seen in your pump's performance curve. We can't tell you that since only you have that specific curve that deals with your pump and the impeller you have inside it. The pressure at the heat exchanger is the pump's discharge minus the hydrostatic head measured from the pump to the heat exchanger. (This is basic 1st year chemical engineering university training; does this thread belong in the Student Forum?)

2) Again, your English is hard to understand, and I think you want to know the pump discharge pressure. The answer is in #2, above.

3) As in #2, I have to assume you now have a block valve that you close upstream of the heat exchanger. Again, same logic as in #1. It all depends on the pump's performance curve for the impeller used.

Basically, what you are asking for is what is contained in your pump's performance curve. A centrifugal device follows the path dictated by its performance curve. This is too easy...; perhaps I mis-interpreted your English. If so, please correct me.

If you maintain the pump dead-headed without any flow through it, you will start to accumulate a heat build-up in the water. If that water is saturated, it could start to boil and create steam --- that's why I asked about the physical state of the water.