Hy Sys Exercises

HYSYS Exercises Table of Contents Exercise 1. A Cascade of Drums.......................................................................2 Solution 1. A Cascade of Drums....................................................................3 Exercise 2. Joule-Thomson effect.....................................................................7 Solution 2. Joule-Thomson effect............................................................8 Exercise 3. Create Pseudo-components.........................................................10 Solution 3. Create Pseudo-components......................................................11 Exercise 4. Simulation Control........................................................................12 Exercise 5. An example...................................................................................14 Exercise 6. Cooler...........................................................................................14 Solution 6. Cooler.........................................................................................16 Exercise 7. “Reset” functionality......................................................................19 Solution 7. “Reset” functionality...................................................................19

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Exercise 1. A Cascade of Drums Category: Target:

Hysys Steady State Get familiar with the Hysys interface. Learn how to set-up the basis environment. Have a glimpse at steady state simulation in Hysys.

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An equimolar mixture of C1, C2, C3, iC4, nC4 flashes into a drum that is maintained at 20 bar. The feed rate is 50 tn/h at 0 deg F and the feed pressure is 25 bar. Subsequently, the liquid product of the first drum is flashed again at 15 bar. 1. What are the temperatures of the drums? 2. Which is the composition of the liquid stream of the second drum? Solution guidelines 1. Load Hysys (stand alone) 2. Enter into the basis environment 3. Set-up component slate and thermodynamics 4. Use the Palette (F4) and create the system configuration. 5. Add DP at drums (Design tab – Parameters) 6. Make sure that the “case” runs 7. Answer the questions and compare with the “correct” answers 8. Save your case.

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Solution 1. A Cascade of Drums

Figure1.1. Hysys set-up

Figure1.2. Component slate set-up

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Figure1.3. Fluid Package (thermodynamics) set-up.

Figure1.4. Definition of pressures in the system

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Figure1.5. Solution: System temperatures

Figure1.6. Solution: mass flows

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Figure1.7. Solution: mole flows

Figure1.8. Solution: mole fractions

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Exercise 2. Joule-Thompson effect Category: Target:

Hysys Steady State Get familiar with the Hysys interface. Learn how to set-up the basis environment. Problem solving with Hysys.

I have 1000 kmoles/hr of air at 6 bar and 35 deg C. Can I release this pressure in a throttle and cool this air by using the Joule-Thompson effect? What would the difference be if I had ethane, ethylene, propane or propylene instead?

Solution guidelines 1. The exercise can be rephrased as: “Prove that air is not a refrigerant fluid”. 2. We need to do a simple flash calculation. This can be done using a drum of a valve or anything similar. 3. Set the system up: basis environment, feed stream etc. 4. Answer the question posed. 5. Examine what-if scenarios using different fluids and compare the results.

The exercise is based on material from: The Chemical Engineer's Resource E-Mail Archive (http://www.cheresources.com/em002zz.shtml).

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Solution 2. Joule-Thomson effect.

Figure 2.1. Set-up.

Figure 2.2. Thermodynamics definition.

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Figure 2.3. ΔP definition.

Final results are as follows (SRK): Substance Temp (deg C) at outlet ΔT (deg C) Air

33.90

1.1

Ethane

29.87

5.1

Ethylene

30.19

4.8

Propane

27.59

7.4

Propylene

27.40

7.6

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Exercise 3. Create Pseudo-components Category: Target:

Hysys Steady State and Hysys Dynamics Learn how to set-up the basis environment and define pseudocomponents.

Create a feed stream. This should be an equimolar mixture of five components with normal boiling points at 200, 280, 425, 630 and 920 deg F.

Solution guidelines 1. Load Hysys (enter basis environment) 2. “Hypotheticals” tab 3. Add, Add Hypo, enter name and properties (normal boiling point), Estimate Unknown Props. 4. Repeat for all compounds. 5. The missing data: for the component with normal boiling point of 920 deg. F, the liquid density is 60 lb/ft3. 6. Exit window, go to the “Components” tab and select “View” 7. Select “Hypothetical” at the left hand side and add the components you want. 8. Proceed as normal to create the feed stream. 9. Be careful with the units that you are using.

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Solution 3. Create Pseudo-components

Figure 3.1. Definition of a single pseudo-component.

Figure 3.2. Simulation Basis Manager, “Components” “Hypothetical” selected (left-hand side of the window).

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tab,

View,

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Exercise 4. Simulation Control Category: Target:

Hysys Dynamics Get familiar with the Hysys integrator and understand its options. Dynamic testing. Modifying ambient temperature.

We will perform dynamic testing and at the same time explore the capabilities of Hysys integrator (Cntrl-I). Re-Load SmallHysysDemo.hsc and identify D119-DL1 trend graphs (minimize the PFD sceen of go to the “Databook” via Tools Menu – Databook or via Cntrl-D. We will focus on the red line, the temperature of the drum. Start running the case.

Figure 4.1. Databook and relevant trend at steady state.

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1. What is the real time factor? I.e., how many times faster than real time are we running at? 2. Move the mouse fast! What is the real time factor? 3. Stop the simulation. Set the current time to zero. Restart the simulation. 4. Set the display interval to 10 minutes. What is the real time factor? 5. Re-set the display interval to zero (continuous update of data). 6. Simulate a cold night at Chicago. Set the temperature to –20 deg C. 7. Why wait to see the final temperature? Accelerate the simulation! 8. Accelerate the simulation MORE! Any remarks? 9. Reload the case if needed. 10. Run at 3 times real time only. 11. Stop the simulation and run for 10 minutes. 12. Try the “Reset” button while running at accelerated speed.

Figure 4.2. Note the behavior of the percent liquid volume in the drum when running at high acceleration.

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Exercise 5. An example Category: Target:

Hysys Dynamics Create a full flash drum. Create trends. Dynamic testing.

Please create the following characteristics of all blocks.

model. Pay attention to

PV100 6" Cv = 400

8"

MV100 8" Cv = 10000 100% open

Flare 1.013 bar

D-100 FV100 4" Cv = 400

Feed 12.43 bar 35.43 oC

the dynamic

Ambient Temperature = 25 oC

4.5 m

P-100 6"

Ground FC100 Flow Controller SP = 15000 kg/h Kc = 0.3; Ki = 0.2

MV140 6" Cv = 10000 100% open

MV120 6" Cv = 5000 100% open

5m

D-100 Vertical Drum Height = 6 m Diameter = 3 m

P-100 Pump Use given curves

LV100 4" Cv = 200

Drain 1.5 bar

LC100 Level Controller SP = 30% Kc = 2; Ki = 5

PC100 Pressure Controller SP = 2 bar Kc = 0.2; Ki = 0.3

1. Create trends (strip-charts): All controller measured variables and controller outputs, pump flow and pump head. 2. Do the following tests: - Decrease the feed by 50%. - Shut down the system. - Start-up the system. - Increase the feed to 150 and 300%. - Reload the original case and add a spare pump. Switch the pumps over. 3. What do you remark at each of the above tests? 4. Add a second pump. Use the event scheduler to ramp the flow controller set point to 120% of the original value. 5. Add a spreadsheet to calculate deviations from the client steady state.

Exercise 6. Cooler Category: Target:

Hysys Dynamics Heat transfer equipment. Split range control.

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1. Load SmallHysysDemo.hsc and add cooler E100 at the end of the system (after stream SLOPHEADER). Use reasonable data. 2. If the temperature at the end of the cooler is 25 deg C, what is the cooler duty? 3. If the cooling duty is 100 MJ/hr, what is the temperature at the end of the cooler? 4. What is the temperature at the end of the cooler if you use 2 tn/hr of water at ambient conditions as utility? 5. Re-do question 2, using a temperature controller, acting on the duty of the cooler. 6. Re-do question 2, using a three-way valve, i.e. a bypass stream and a split range controller.

Solution guidelines None! The trainee should be able to finish the exercise without much help!

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Solution 6. Cooler

Figure 6.1. Block connectivity Reasonable data used: 1. Downstream pressure spec of 1 atm. 2. Simple heat losses (10 m2, 10 MJ/hr) 3. k=40, leading to ΔP across the cooler of 0.12 bar. If k=23, then ΔP is 0.33 bar. Duty is 200 MJ/hr when the end temperature is 25 deg C.

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If the cooling duty is 100 MJ/hr, then the temperature at the end of the cooler is 29 deg C.

If we used 2 tn/hr of water at ambient conditions the results are as follows (essentially as before!). Note the effect of the average UA as well.

Use split range control as follows (DCS integration reasons only):

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Exercise 7. “Reset” functionality Category: Target:

Hysys Dynamics Logic blocks

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Typical reset functionality is shown below in block diagram format:

Reproduce the functionality, by applying this to an isolation valve: 1. Add an isolation valve in series with a manual valve. Cv should be large and 100%. 2. A bad process signal (continuous) will close the isolation valve. 3. If the process signal becomes good, the valve will not open before the operator sends a reset pulse.

Solution guideline: Reproduce the construction shown below.

What are your remarks?

Solution 7. “Reset” functionality

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Figure 7.1. Faceplates of logic blocks used to reproduce the “reset” functionality.

Figure 7.2. Details or the latch (SR) block and the digital point used to interface with the valve.

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Figure 7.3. Details or the reset (pulse) block used.

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