A development of an electrical analogue for thermal processing : a thesis presented in partial fulfillment of the requirements for the degree Master of Technology in Biochemistry at Massey University

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a copy to be downloaded by an individual for the purpose of research and

private study only. The thesis may not be reproduced elsewhere without

the permission of the Author.

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A thesis presented in partial fulfilment of the requirement for the degree

MASTER OF TECHNOLOGY i n Biotechnology

At Massey University Palmerston North

New Zealand

SURAPONG NAVANKASATTUSAS 1973

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ACKNOWLEDGEMENTS

The writer ~ishes to express his gratitude for the generous assistance and guidance which he received throughout this work,

witho~t whi ch thi s study would hRve been impossible.

The writer would lik0 to thank Professor R.L. Earle for his continual teaching and guidance throughout this study"

To Mr. R.E. Hendtlass , Chemistry, Biochemistry and

Biophysics Department, whose suggestions and contribution of the el ect rical circuits is deeply appreciat ed.

Than~s are also due to the staff of the Food Science and Biotechnology Faculty, Massey University, for their aid.

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TABL

E

OF CONTENTS

I .

SUMfvl ARY o • • • • • • • • • • • • • • o Cl • • • • • • • • • • • • • • • o • • • • • • • • •

Page 1

II. INTRODUCTION

A. T

HERMA

L PROCESSING IN GENERA

L

•••••••••••••••• 3 B. PR OBLEM

S

I

N

FORM ULA TING

t.ND MANIPULATING

PROCESSING COND

ITIO

N . . . 4 C. THE O

B

J

ECTIVE OF THIS STUDY

•••••••••••• • ••••• 5

III .

LITERATURE SUR

VEY

A, K

I

NETICS OF THERNAL PR

O

CESSING ... 6

1 • Reaction Rate Equation ^• • • • • • • • • • • • • • • • • 0 •

6

2. Temperature Dependency of Reaction

Rat e Constant ••••••••• ••••••••• ••••••••••

8

B.

T

H

ERMAL PROCESSI

NG

EVALUATION

• • • • • • • • • • . • • • • •

13 C, ANALOGUE SYSTEM FOR THERi,iAL PROCESSING • • • • • • • 15

IV . THEORY

A, GENERATION OF REACTION

RA

TE FOLLmJING THE

ARRHENIUS

EQUATION ···~··· ··· ·· 17

1.

Thermistor Sensor

o•W••··· ··· ·

¹⁷

2. Generntion of a Primary Reaction Rate

Following t he Arrhenius Equation

... ... 18

3.

Modification of the Primary Reaction

Rate Constant •••••••••••••••••••••••••••• 19

B.

I

NTEGRAT

ION OF

THE GENERATED REACTION RATE

20

C-. CORRELt.TION O F A

N

ALOGUE

OUTPUT

VOLTAGE

v

0

W

ITH

PRO

GRESS OF IEREVERSIBLE REACTIO

N I

N

THERMAL

PROCESSING ···~··•••••••·••••• · ··~~~~·· 22 1. Irreversible Unimolecular First-order

Reactions ·•·'• ·• ... • . . . ~ .... . ...•. ·-··. . . . • • 22 2. Irreversible Bimolecular Second-order

Reactions -... . . -.. -. . . . ... . . .... ,.. . .

24 3.

Irreversible Trimolecular Third-order

Reactions ... ~ .. -. . . ... ... . . . ... .. . .. . . . . . ... . . 27

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4.

Irreversible Reaction ~ith Empirical Rate Equation of the n th Order

5 .

The R8l~tionshtp of the Ratio of Frequi::ncy li'ac to1· and the Ratio of Reaction Rate Constants at a Constant '.i.'emperature

Page

30

31

V" AP:OARATUS

B,

REGUL~T~D FO~SR

surPLY

FOR THE

ANALOGUE SYSTEM

• ELECTRICAL A!'JALuGUl~

SYSTEJvi

1. Primary R0action Rate Generator .•••.•.••• •. Analogue Multiplier

Analogue Litegr:itor

33 33 33

34

C. THERhAL PROCESSING

REACTOR

•••. , . . . • . . • • • . • • . • . •

: 35 D. MEhSURING EQUIPMENT.

. ... ... ...

..

...

.

. ... ...

36

1 ,,

v

01 trn et er () ,.., ^ti^c ⁰ ⁽ ⁰ ⁰ ⁰ ⁰ ^t) ^')^• ⁰ ^& ^{. . .}^,^" ^a⁰ ^• ^" ⁰ ⁰ ⁰ ⁰ ⁰ ⁰ ^• ⁰ ⁰ ⁰ ^• ⁰ 36 2. Potentiometer and ~hPrmocouple •••••••••••••

36 3 .

Potentiornet1·i.c Recorders • • • • • • . . • • • . • . • . • . •

3 6

VI. ?ROCEDURE

VII.

VIII.,

A.

ARRANGD!ENT

OF

APPARATUS

FOR EXP~RIMENTAL

TESTING OF 'I'HE ANALOGUE SYSTEM • • • • • • • • • • • • • • • • • 4 3 B. DETERMINATION OF GENERATED

PRIMARY REACTI ON

"RATE

v

1 A'l' V.1-\RIOUS

TEMPERATURE

T •• , • • • •• • • • • •• • 11-3

C. ~ETERMINATION

OF GENERATED SECONDARY REACTI

O

N

RA':::'E v

2 AT VARIOUS TEMPERP'I'URE T , •••••••

o . . c. .. 44

D. TESTI

NG

OF THE

ANALOGUE

INTEGRATOR. ... .

.

...

44

E. A

PPLI

CATION

OF THE

ELECTRICAL

ANALOGUE

IN

TH

ZRMhL

PROCESSING ^O ^• ^~ ^t'l" ^• ^••• ^• ^• ^•oo:o ^o•• ^,. ^• ^• ^• ^{•••••••}

RESULTS " • ^e⁰ ^c⁰ ^{u •}^Q ^• ¹ ⁰ ⁰ ⁰ ⁰ ^,.^" ⁰ ⁰ ^')⁰^• ^(\• • • • 0 (t " e • .• " • • • • • • • • 0 •

50

DISCUSSION OF

RESULTS

A 0 TES TI NG OF THE ANALOGUE SY STEM ^o^• ^• • • , " • n • • • • • • • • 64 1. Generation of the Primary Reaction Rate v

1 . 64 2. Generation of the Reaction Rate v2 with

Application of the Analogue Multiplier ••••• 64 j. The Analogue Integrator •••• ••••••••••••••••

65

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B. THE ANALOGUE .SYSTEM I N THERMAL PROCESSI NG

IX. CONCLUSIONS .., •• 0 0 0 0 0 0 0 • . ; • • • • • • • • • • - > • • · · ·

APP EI'ID IX .. . . ,, . . . • . . . • . .

BI BLI OG RAP HY . . . ., •••• ~ ... ., •••••••••

Page

67 88

90

101

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Table VII.1

Table VII.2

Table VII.3

Table VII.4

Table VII.5

Table VII .6

Table VII.7

Table VII.8

Table VIII.1

LIST OF TABLES

Page

Results of Primary Reaction Rate v 1

Generated by the Analogue •••••• ••••.••• 51

Results of Reaction Rate v 2

Generated by Lpplication of Analogue

Multiplier (n=2) • ••. ••••••. •••• •••• •••• 52

Generated by Application of Analogue

Multiplier (n=4) • e • • • • • • • • • • • • o• • •• • • • • 53

Generated by Application of hnalogue

Multiplier (n=6) •• •••••••••••••••••••••

54

Multiplier (n=8) • n•• •• • • • o o•• • • • • •• • • • • 55

Generated by Application of hnalogue

Multiplier (n=10) •••• ••••••• •••••••••• • 56

Multiplier (n=12) •••••• ••••••• ••••••••• 57

Multiplier (n=16) •••••• •••••••• ••• •••• • 58

Summary of Results in Reaction Rate

Generation by the Analogue ••••••••••••• 70

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Table VIII.2

Table VIII.3

Tabl e VIII.4

Table A.1

Table A.2

Table C.1

Measured Output Voltage Changes of Integrator at Various I nput Voltages

Comparison of Progr ess of the Thermal St erili zat ion Det ected by the Analogue and that by the Temperature-time

Page

71

Profil e ••o • • • • • • o • • • • • • • o • • • • ••o • • • • • • • 72

Comparison of Progress of the Thermal Destruction of the Chemical Species Detected by the Analogue and that by the Temperature-time Profile

Charact eri sticsof Copper-constantnn

73

Thermocouple ••••••••••••••••••••••••••• 91

Relationship of Inverse Absolute Temperature at Hot Junction and Electrical Potentinl of the Copper-

constantan Thermocouple ⁰ ^Cl• • • • • • • • • • • • • •

Pertinent Values Associ at ed wi th Analysi s of Exper imental Reaction Rates Generated

92

by the Analogue

e•••••••• •· ·· ·· · · · ··· · · ·

⁹⁸

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Figure V .1

Fi gure V.2

Figure V.3

Fifjllre V

. 4

Fi gure Vo5

Figure VI.1

Figure VII.1

Figure VII.2

Figure VII.3

Figur e VII.4

LL3T OF FIGURES

Circuit Diagran of the Voltage

Regul~ted Power Supply ••• •••••••••••..•

Circuit Ding~am of the Primary

Page

38

Reaction R~te v1 Generator ~···••••••• 39

Circuit Di ·tgram of an Analogue

Multiplier.. . . . .... . . ... . .. . . . 40

Circuit Diagram of the Analogue

Integrator •.. ,, ...

o... . .... .. . .. . .. ...

⁴¹

Dingram of Wiring Through the Door

of the Autoclave •n•••••·• ••••••••• ••••• 42

Arrangement of Apparatus for Testing

the Analogue

•n•••• ·· ··· ··· · · ··· ·

⁴⁹

Results of 11nalogue Integrator

Testing ^• ^{• • :=»}^{• • •} ^{• • • 0} ^. ^{. . .}. . . .. . . .. .. . . .

Output Voltage from the An~logue

System in Following the Progress cf the Sterilization of a Microorganism

Temperature and Time Profile in the Vicinity of the Sensor of the An~locue

59

60

in a Microbial Sterilization . . . 61

Output Voltage from the Analogue System in Following the Progress of the Thermal Destruction of the

Chemical Species •••••• ••••••••••••••••• 62

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Figure VIIo5

Figure VIII .1

Figure VIII e2

Figure VIII .,3

Figure VIII.4

Figure VIII o5

Figure VII.6

Figure VIII.7

Figure VIII.8

Temperature and Time Profile in the Vicinity of the Sensor of the hnalogue in a Chemical Destruction

Reaction OO¥o•• • egeeo•oe • • • ••• • ••• • • • • • ••

Plot of the Primary Reaction Rate Generated by t he Analogue According

Page

to the Arrhenius Equation (n=1) ~ ·· ··· 74

Plot of the Reaction Rate Generated by the Analogue According to the

Arrhenius Equation (n=2) •••.••••••.•• ••• 75

Plot of the Reaction Rate Genernted by the Analogue hCcording to the

Arrhenius Equation (n=4) ••. •••••••••.••• 76

Plot of the Reaction Rate Generated by the Analogue According to the Arrhenius

Equation (n=6) •••• ••••••.•. .• •••.••••••• 77

Plot of the ReAction Rate Generated by the Analogue According to the Arrhenius

Equation (n=8) ••. •••. •••.•••.•••••• •••. • 78

Equ~tion (n=10)

n •• •• •··· · · ··· .... . ... ..

⁷⁹

Equation (n=12) •o••••• •••••••••••••••••• 80

Equation (n=16) ~oonc~• •••••• •• •••n•• • • • • 81

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Figure VIII.9

Figure VIII e 10

Figure VIII .11

Figure VIII.12

Figure VIII.13

Figure VIII .14

Figure A~1

Figure A.2

Relationship between Temperature Coefficient of Generated Reaction

Page

Rate and Integer Multiple n •••• ••• ••• ••• 82

Measured Output Voltage Changes of Integrator at Various Input

Voltages • • • • o • • t ie••oo • ., o• •• • • • • • • • o• • • • • 83

Reaction Rate and Time Profile in the Vicinity of the Sensor of the

Analogue in a Thermal Sterilization 84

Progress of the Thermal Steril ization Detected by the Analogue and th~t by

Temperature and Time Measurement •••••••• 85

Reaction Rnte and Time Profile in the Vicinity of the Sensor of the Analogue in a Thermal Destruction of a Chemical

Species f'l oo• • • • t> • oo • .. • • • • • o • • • • • o , , • o • o•• • 86

Progr ess of the Thermal Destruction of the Chemical Species Detected by the Analogue and that by Temperature

and Time Measurement '· •••••

o. . . . . .. ... . ..

⁸⁷

Characteristics of Copper-constantan

Thermocouple • • • • • • • • • • •••• •••• o•• • • • • • • 93

Relationship of Inverse Absolute Temperature at Hot Junction and El ectrical Potential of the Copper-

constantan Thermocoupl e _o_{e o •}$ • • • • • • • • o • • 94

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I. SUMMARY

The objective of this study was to investigate some general principles in thermal processing and some methods for following this processing experimentally. The emphasis of the investigat- ion was to develop a simple electrical analogue system for

followinB the progress of a single stage irreversible thermal processing reaction.

Documented data and principles of the kinetics of thermal processing of biological material showed that such process reaction could be approximated by the kinetic model of a single stage irreversible reaction. Temperature dependency of the thermal processing rate could also be approxim~ted by the Arrhenius equation.

Functional principles of electrical analogue computers were applied to develop the electrical analogue system. The

structure and mode of operation of this system is described.

The relationship between the output voltage of the analogue system and the progress of the thermal processing are derived for different known thermal processing reactions, following the kinetic model of a single stage irreversible reaction.

The performance of the electrical analogue system in this study was tested. The results indicated that the electrical analogue system so constructed could approximate the function described in theory. Non-ideality of the electrical circuitory, however, restricted the application of the electrical analogue system for its qualitative value only. The parameter governing

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the temperature dependence of an irreversible reaction rate could be generated with error of approximat ely ~

4.55% .

^Thê êrrôr

associated with application of the ~nalogue integrator for

integrating the generated reaction rate w&s approximately ~

7 . 25 % .

The overall error in application of the analogue system for

detecting thermal processing varied with the time span of processing cycle₁ and processing effect achieved at temperatures other than the set temperature of processing.