1. Pump :
Pump is used to increase pressure of inlet
liquid stream (the inlet stream must be liquid).
First, we define the inlet stream, and
define the outlet stream, define energy stream.
Second, we specify Delta P or directly you
can specify the pressure of outlet stream and we specify the adiabatic
efficiency.and click on, if you don't click on pump will not boost the stream, pump will work with 0.00 Delta P.
Finally we get our Pump converged
One thing, it exists another method to converge
pumps, method of "curves", this method works with Equation of Head.
H = A + B*flow + C*flow^2 + D*flow^3 +
E*flow^4 + F*flow^5
You have to define first:
- the unit of head
- the flow basis
- the unit of flow
Second fill out coefficients A,B,C…….
finally you have to click to "activate curves"
For this method, it is more real in calculation, because you give the flow
and Hysys will calculate automatically the Delta P, the pressure of outlet
stream…….
2. The compressor:
Compressor is used to increase the pressure of
a stream (the stream must be gas, vapor).
First, we define the inlet stream, define
the outlet stream, and define energy stream.
Second, we specify Delta P or directly you
can specify the pressure of outlet stream and we specify the adiabatic
efficiency.
In Hysys, it Exists 2 types of compressor:
- Centrifugal Compressor
- Reciprocating Compressor
a. Centrifugal compressor:
Centrifugal compressor is used for high capacities
of stream and low compression ratios.
Centrifugal compressor also can be used to
represent a pump, when more rigorous pump calculation is required; in Hysys the
pump operation assumes that the liquid is incompressible, so if you want to
pump a liquid near to critical point (where it becomes compressible) here you
can represent the pump by the centrifugal compressor.
In centrifugal compressor exists tow
methods of calculation:
- Without curves
- With curves
Without curves:
like the first example in
Compressor, after defining elements (inlet stream, outlet stream, energy stream).
After we specify efficiency (adiabatic or polytropic) with picking the method
of polytropic, we specify Delta P or Pressure ratio or directly the outlet
pressure
With curves:
We click Rating, curves, and we pick the type of efficiency (adiabatic or
polytropic), after that we click Add curve.
After clicking Add curve, we the units of flow and head after that we
specify Volume flow, head and the efficiency.
After that we clock at Activate and Enable curves.
If you notice the yellow case that written
on it “Efficiencies greater than 100 percent” this problem result in low flow (the
centrifugal compressor used for higher flow and low compression)
Therefore, we have to increase the flow
b. Reciprocating Compressor:
This one type of compressor is used for applications
where higher discharge pressures and lower flows are needed.
First, we have to define streams (outlet
and inlet) and the stream energy.
Second, we specify Efficiency (adiabatic or
polytropic) and we define the delta P or pressure ration or the Duty of
compressor or directly the outlet pressure
3. The expander:
The expander is used for decrease the pressure
of stream (the stream must be gas, vapor phase).
It exists two methods for calculation
- Without curves
- With curves
Without curves:
After defining elements (streams and energy
stream), we specify the efficiency (adiabatic or polytropic) and we define the
duty of expander or delta P or the pressure ratio or directly the outlet
pressure.
With curves:
First we click rating, curves, add curve.
After that, we have to define units of flow
ad head; we specify the volume flow, head (here for the expander the head must
be negative) and the efficiency.
And we finish by clicking Activate and
enable curve
Notice:
If we use the method of curves in
the centrifugal compressor and expander, we don’t specify the outlet pressure
or the duty or the Delta P………..
If we use the method of curves, Hysys
will calculate all of those parameters.
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