Simulation With Aspen HYSYS: Simulation of Heat Transfer Operations ( Heater/cooler, Heater Exchanger, Fired Heater, LNG, Air cooler) with Aspen Hysys.

1. Heater :

This operation is useful when you are interested only in how much energy is required to heat a process stream with a utility.

We take the same streams used in the last example (the distillation column in first post)

Here for this equipment we need only one stream.

Therefore, you converged already the stream (we take the stream 1 from the example of distillation column in the first post)

First, we have to define the names of inlet, outlet stream and energy (how we can define them !! it’s very simple: by written, but the inlet stream must be converged).

We enter to the heater equipment by double click, we click connections and we dot like in the Fig

How you can know yourself that you did the first step correct? You know it from the yellow case (Unknown Delta P) if he displayed that, it means you finished with the step of define streams. J

Second step that you should be do it, specified the Delta p, or you specify the pressure of outlet stream (Stream 1 hot) and specify the duty of heater (after calculating sure) or you can specify directly the outlet stream Temperature desired.

We are always in Heater options; by click in parameters, we specify the Delta P and Duty value or T of outlet stream

After that we get our equipment converged

2. Cooler :

The cooler equipment is used when you are interested only in how much energy is required to cool a process stream with a utility.

He has same principal of the heater but in the opposite sense, how!

For example the Equation of energy:

For the cooler:

Heat Flow _inlet – Duty _cooler = Heat Flow_outlet

The heater:

Heat Flow_inlet + Duty _Heater = Heat Flow_outlet

We do the same steps of heater :

Step 1

Define names (inlet, outlet stream, energy)

Step 2

Specify Delta P or outlet stream pressure and the duty value or directly the temperature of outlet stream

And finally we get our cooler converged

3. Heat exchanger :

For this equipment you need two streams (Hot fluid and cold fluid), so what does happen really, the hot fluid supplies the Heat Exchanger duty to the cold fluid.

We will take the streams from the last example,

Stream1

	Stream 1	Stream 2
T (°C)	97	188,8
P (bar)	15,5	15,5
Molar flow (kmol/h)	737,96	256,75

First we have to define names, double clock to the exchanger heat, after that we click connections

Now click parameters, specify Delta P or directly you can specify the pressure outlet stream (for the both streams, also Delta P), after that you specify UA (overall Heat transfer coefficient per total area of heat transfer) or directly you have to specify the temperature outlet stream (just you need one temperature outlet stream, the other Hysys will calculate it)

About the compositions you can return to the first post (example of Distillation column).

About the Ft factor we will ignore it because we don’t need it now (we work an

Ideal case, also the heat leak/loss we select none (it means by default))

After that we get the heat exchanger converged

4. Fired Heater :

Fired heater (furnace) contains three zones

Radiant Zone
Convective Zone
Economizer Zone

Now about specification, you need to specify three streams:

Flow inlet (stream who we want to heat)
The fuel gas (generally we use naturel gas C1 and C2 in compositions)
The air (O2+N2) and this one we have to define compositions as O2 and N2 , not Air

	Stream
T (°C)	97
P (bar)	15,5
Molar flow (kmol/h)	737,96

After that, we have to define the stream (flow) outlet, the fuel gas product.

Now click parameters and we have to specify the efficiency of the furnace, and for the flame type, I guess it’s not important in steady state (static), and the excess air present used for calculate the flow of Air, or you can specify derctly the flow of Air

Notice :

Just something, in steady stade mode (Hysys version 7.2) we can simulate only the Radiant Zone, the convective and Economizer Zone available only in the dynamic system

Now, we get the fired heater converged

5. LNG : (the correct version soon)

6. Air cooler :

This Equipment uses ideal air to cool or heat an inlet process stream to a required exit stream condition.

	Stream
T (°C)	97
P (bar)	15,5
Molar flow (kmol/h)	737,96

First, we have to define inlet stream and the outlet stream,

Second, we have to specify the Delta p, or define directly the outlet stream pressure and we have to specify the Overall heat transfer coefficient UA or directly we specify the outlet stream T.

Third, we have to define the number of fans.

Finally, we have to define the pressure and the temperature of Air, after converged, Hysys calculates the outlet air temperature, and if we specified T of outlet stream, Hysys will calculate the Overall heat transfer coefficient.