Solutions for R&D to Design
preFEED

KIChE Fall Meeting
Industrial Practice for Process Operation and R&D – Present and Future

Conceptual Design and Its Role in Process Design

October 2006
Dr. Yoshio Kumagae, preFEED Corporation
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preFEEDAgenda
Freshman and Experienced Engineer
Challenges
Rigorous Simulation vs. Common Sense
１．Distillation, or not ?
２．Install Steam Turbine, or not ?
3. Which can capture the image ?
Recommendations
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Freshman vs. Experienced Engineer

3
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preFEEDSize of a pipe for 100 m3/hr water ?
• If the velocity is 10 m/s, then thesize is 59 mmD.
• If 100 m/s, then 19mmD.

• The diameter should be 130 –190 mm,• because the velocity must be 1-2
m/s for liquids.
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Experienced Engineer
Experienced Engineer can• estimate the approximate size ofequipment without computer.

• check the detailed calculation
without computer.
Experienced engineer has the knowledge ofstandard values, first question to ask, quick
calculation, meaning of parameter value.

He has common sense of process design !
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preFEEDChallenges

6
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40-14yrs old [million]

Population [million]

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3Future

2
1

Year

70%

“Are you interestedin science?”

60
All ages

50
40

Less than 30 yrs old

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2030

2020

2010

2000

1990

1980

0

• Population of 0-14 yrs old,source of future engineers,
will decrease to 1/2(2025/1980).
• The human resources will7
be reduced further.

preFEEDOn the other hand, Your Company’s Expectation from You Is..

How many years will your boss be patient foryou to accumulate experience ?

Typical Answer by Managers:“5 years” after joining the company

8Solutions for R&D to DesignHow About Today’s Engineers ?

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Results of 100 Common Sense Questions
Know well Not sure Never heard of
How to use
triangle diagram ?

Meaning of parameter"B" of Antoine equation ?

If realtive volatility is 2,
is it a difficult separation ?

Concern over today and future
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preFEEDToday’s Challenges and Needs for Training• Gap between expectation and reality• Concern over future human resources
Reasons why we need to train our engineers
Train engineers so that (1) they can make thebest use of process simulator if applicableand (2) they can design processes without
simulator if not applicable.
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Rigorous Simulation vs. Common Sense

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Many design options are theoretically feasible, but onlya small number of designs have survived. They havetechnical and/or economical reasons.
The knowledge related to them are accumulated ineach experienced engineers after a long trial and error
efforts.
They are called “rule-of-thumb”, “heuristics”, “back-ofthe-envelope calculation”, “common sense (of processdesign”, which are related to conceptual process
design.
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Rigorous Simulation vs. Common Sense
1. Distillation, or not ?

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Separation of o-/p- dichlorobenzene (bp=180/174 C)

I used AspenPlus tocalculate the distillation
column. It looks theseparation is not easy.
Should I continue thecase studies? Or doyou have somesuggestions?

A: Let me
check yourcalculation first.
Can you sendme thesimulation file?

B: Run morecase studies.
Nth= 50, 100,
150 and RR=
10, 50, 100.

C: As the boiling points
difference is only 6C,
distillation is notpractical. Make
research on otherseparations. 14
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Crystallization for p-dichlorobenzene production

Crystallizer No. 2

Purifier

Crystallizer No. 1
FeedResidue

Product

Coolant
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Coolant

Heater15

preFEEDWhy 6C Difficult for Distillation ?

We may realize this fact after many case studies.

Better way ?
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preFEEDWhy 6C Difficult for Distillation ?

Nact=1350/ΔT
Rigorously speaking, we need components,VLE, target purity to calculate the number ofstages.
However, existing columns have commonfeatures.
“Molecular Chemical Engineering for Process Design”(Kawai, Mitsubishi Kasei, November 1987)

Common Sense As“Quick calculation method from experience”17
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Rigorous Simulation vs. Common Sense
2. Install Steam Turbine, or not ?

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What Is Best for Energy Saving ?

Do you think it agood idea to install
steam turbine tosave energy of myplant site?

Maybe. Do you
know the steam
demand andelectricity demandon your site?

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Energy Saving Planning

Total steam
consumption is 300
t/hr and electricity
consumption is 100
MW.

My suggestion is that you
consider Gas Turbine
first. You can also study
steam turbine to combinewith gas turbine.

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Steam turbine system produces steam [t/h] andelectricity [MW] with the ratio of 6-17.
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preFEEDsteam[t / hr ]electricity[ MW ]=2-4

= 1.5 - 3

22
Solutions for R&D to DesignCommon Sense As“Procedure and figures from experience”

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Combined cycle02

Gas Turbine

468

Steam Turbine

10

Chemical Plant

Furtherenergysaving isdifficult.
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Install Gas
Turbine andCombined
Cycle to reduce
electricity
further.

1214

RefineryIntroduce site
steam turbine
system toreduce
electricity cost.

Start theenergy saving
here.
Steam is easierto reduce thanelectricity23

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Rigorous Simulation vs. Common Sense
3. Which can capture the image ?

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preFEED“We conducted experimental study,ran simulator and found (A) thisreaction is in 1st order and (B) therate constant is 10 [1/min].”“Is it a fast reaction ?”25
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Answer #1• Look at unit of k=10 [1/min].
• [1/min] is not familiar to us, but [min] is a familiar unit.
• Take the inverse of [1/min], then we obtain 0.1 [min].
• This must be some time constant related to thisreaction. 0.1min is 6 sec.
• This sounds like a fast reaction, but I should compare
it with other time constants such as residence time ofreactor.
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Solutions for R&D to Design

preFEEDAnswer #2, more theoretically

A0AedA= − kAdt

Ae− kt B=eA0tB

1. half-time = ln(2)/k = 0.693/10 = 0.0693 min = 4.2 sec
1’. “time to 1/e (≈40%) = 1/k = 0.1 min = 6 sec
2. We need other time constants for comparison.

Common Sense From
Theory (Physical Chemistry)
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Recommendation

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preFEED• Common sense, rule-of-thumb, heuristics,back-of-the-envelope calculation are critical forcorrect judgment to complicated calculations.
• Their sources are not only experience but also
physical chemistry.
• They are essential compliment to processsimulation for conceptual process design.
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Check theresults with
Rule-Of-Thumb

A new finding

Check theresults with
Rule-Of-Thumb

Prediction frominitial model
Additional data
Refined model
Experimental
Work
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Modeling &Simulation
30

Solutions for R&D to DesignpreFEEDThank you for your attention !
PreFEED Corporation provide(1) Advanced Chemical Engineering Training (Data Analysis; Phase
Equilibrium; Batch vs. Continuous; Modeling; Rule-Of-Thumb)(2) Modeling Consultancy(3) Support to Equation Solver
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