Orientation

LAB-IV (CL 451)

Reaction Engineering, Process Dynamics

and Control

List Of Experiments1. Response of the first order system-Thermometer

2. Response of the second order over-damped system-Thermowell

3. Response of the second order critically damped system-Non-interacting tanks

4. Response of the 2nd order under damped system (simple pendulum)

5. Reaction in Batch Reactor

6. Reaction in CSTR

7. RTD in non ideal CSTR

8. RTD in non ideal LFR

9. HPLC/GC/UV

10. Single Board Heater System1 (SBHS1)



1. First order system: Thermometer

Aim: Determine the time constant of a thermometer from its response to a step change

1 http://users.df.uba.ar/sgil/physics_paper_doc/papers_phys/termo/cooling2.pdf2 http://www.jgsee.kmutt.ac.th/exell/PracMath/Instruments.html

What is step input?

( ) 0, 0, ( ) 1, 0x t t x t t in

pu

t

Application: Modeling base of other first order systems

Governing equations3

Let us define…

First order system:

( )

1

KG s

s

3 Coughnowr, D., 1995. Process system analysis and control. Second Edition, McGRAW-HILL Publications.

Step input response

2. Second order over-damped system: Thermowell 3,4

Aim: Determine the time constant of a thermometer from its response to a step change.

1. Fluid outside the Thermowell2. Fluid in between the thermometer and Thermowell.

What is a Thermowell?A test tube filled with water and a small bulb mercury in glass thermometer fitted at its center. Surrounding fluid: oil.

3Coughnowr, D., 1995. Process system analysis and control. Second Edition, McGRAW-HILL Publications.4http://www.temperatures.com/twells.html

Typical Response to a step input3,5,6

Sluggishness increases with increase in

2 2( ) , 1

2 1

KG s

s s

Transfer Function

𝜏 :Natural period of oscillation: Damping Factor

3 Coughnowr, D., 1995. Process system analysis and control. Second Edition, McGRAW-HILL Publications. 4http://www.indiamart.com/sushiltradingcorporation/spare-parts.html6http://telecom.shirazu.ac.ir/telecom/download/ftproot/Hasseli/Chemical%20Process%20Control%20%20Stephanopoulos/Part%20III/Chapter%2011.pdf

3. Second order critically damped system: Non-Interacting Tanks3

Aim: Determine the dynamic response of the system to a step change in input.

Important: Variation in h2 does not affect h1

Input: qOutput: h2

Governing Equations3

2

1 2

2( )( )

( ) (1 )(1 )i

H s RG s

Q s s s

Critically damped system: A1=A2, R1=R2 and thus, 1 2

3 Coughnowr, D., 1995. Process system analysis and control. Second Edition, McGRAW-HILL Publications.

Transfer Function

Response to a step input

4. Response of the 2nd order under damped system (simple pendulum)

Objective:

To study the effect of inertia and viscous drag on

damping coefficient ()

• General second order system Transfer

Function:

Response curve of under damped system

A

B

COvershoot = A/B = exp(-∏ /

A=angle achieved after first oscillation

B=angle on the starting

After n oscillations,

Over shoot

Batch Reactor CSTR

• Non-steady state • Steady state

Governing Equations

5. Reaction in Batch Reactor

Reaction: Saponification

CH3COOC2H5+ NaOH CH3COONa + C2H5OH

Objectives:

• Finding rate constant (k) at different temperatures

• Activation energy

• Frequency factor

Time Concentration of NaOH Conversion of NaOH

Observation table:

Rate equation for a second order reaction:

-rA=

Assume

Design equation in terms of conversion:

XA/(1-XA)=kCA0t

X A/(

1-X A

)

t

Temperature (T) Rate constant (K)

Room temperature

(Room T + 40)/2

40 oC

Calculation table:

Arrhenius Law:

k=k0exp(-E/RT)

By applying natural logarithm

ln k = ln k0-E/RT

6. Reaction in CSTRReaction: Saponification

CH3COOC2H5+ NaOH CH3COONa + C2H5OH

Objective:Finding out conversion at different flow rates at room temperature

Design equation of CSTR:

Observation table: (Do at 3 different flow rates of Ethyl Acetate)

Time Outflow (yes/no) Concentration of NaOH Experimental Conversion of NaOH

Flow rate of NaOH Flow rate of ethyl acetate

Experimental conversion

Theoretical conversion

FA1 FB

FA2 FB

FA3 FB

Steady state Summary

7. RTD in non ideal CSTR

• Aim:

1. To determine the RTD in constant volume CSTR

2. To determine the conversion of saponification reaction using non-ideal reactor model

8. RTD in non ideal Laminar Flow Reactor (LFR)

Aim:

1. To determine the RTD in volume LFR


Single Board Heater System1(SBHS1)

Identification of transfer function of a Single Board Heater System through step response

experiments

Aim:

1.To perform step test on a single board heater system

2. To identify system transfer function using step response data

Schematic diagram and output Response

0 200 400 600 800 1000 120049

50

51

fan

spee

d

Time (sec)

0 200 400 600 800 1000 120020

30

40

50

Tem

pera

tue(

C)

Time (sec)

0 200 400 600 800 1000 12000

10

20

30

Heat

er c

urre

nt

Time (sec)

Metal Plate

Fan

Temperature sensing element

Heating element

𝑦 (𝑠)= 𝐾𝜏 𝑠+1

∆𝑢𝑠

∆ 𝑦=𝐾 [1−𝑒−𝑡 /𝜏 ]∆𝑢

Output Response of 1st order system with unit step change

Expectations

• Calculate • Obtain steady state gain (• Compute the predicted values

of T vs time using K and . • Plot Temperature vs time for

experimental and Predicted results

0 100 200 300 400 500 60024

26

28

30

32

34

Time(sec)

Teme

pratur

e(C)

Experimental Estimated

10. Single Board Heater System2(SBHS2)

Feedback Control of Temperature using heater input- A Simulation Study

Aim: To perform a simulation study on control of temperature using heater input with PI controller

Simulation study and Equation

𝒖 (𝒌+𝟏 )=𝒖 (𝒌 )+𝑲𝒄 (𝟏+∆ 𝑡𝝉𝑰

)𝒆 (𝒌+𝟏 )−𝑲 𝒄𝒆 (𝒌 )

0 50 100 150 200 25020

22

24

26

Tem

p (

C)

Time (sec)

0 50 100 150 200 25020

30

40

50

60

Curr

ent

(I)

Time (sec)

Expectations

• Write PI code in SCILAB/MATLAB for T control

• Effect of controller parameters (τ, Kc) for a given set point change

11. Single Board Heater System3(SBHS3)

Feedback Control of Temperature using heater input- An Experimental Study

Aim: To perform an experimental study on control of temperature using heater input with PI controller

Experimental study

Time(sec)

Tem

pera

tur

e

Effect of Controller Parameters: τ, Kc

Expectations

• Experiments for Temperature control• Effect of controller parameters (taui, Kc) for a

given set point change

12. Gas Chromatography

• To determine the compositions• Demo Experiment

GC Result

Documents

Orientation