THE CONTROL LABORATORIES OF RAW SUGAR FACTORIES - QUT

[Pages:181]A MANUAL OF ANALYTICAL METHODS

FOR USE IN

THE CONTROL LABORATORIES OF RAW SUGAR FACTORIES

Gardens Point A23205806B A manual of analytical methods for use in the control laboratories of raw sugar factories.

Disclaimer: In some cases, the Million Book Project has been unable to trace the copyright owner. Items have been reproduced in good faith. We would be pleased to hear from the copyright owners. Queensland University of Technology. Brisbane, Australia

The Jamaican Association of Sugar Technologists 1987

Lithographed in Jamaica by University School of Printing

PREFACE TO SECOND EDITION

The Committee of Comparative Factory Returns of the Jamaican Association of Sugar Technologists published the first edition of this Manual in an effort to standardise all analyses used for factory control purposes in the sugar factories, of Jamaica so that factory chemical reports might be rendered as comparable as possible. The large proportion of sugar cane now milled and bought on a recoverable pol % cane basis reinforces the necessity for the standardisation and accuracy of all sampling and analytical procedures.

The Manual contains what the compilers consider to be the minimum of instructions and related information necessary to enable factory reports to be prepared in accordance with the form of presentation used in Jamaica. Only the actual operating instructions for performing the analyses are given; the theory of the respective analytical methods can be found in any of the standard published works on sugar analyses. The essential aim has been brevity, simplicity and accuracy, consistent with the practical requirements of factory control. First Aid precautions and a few miscellaneous analyses have been included for easy reference.

The Manual in its present form represents the combined efforts of the members of the Chemical Control Committee of the Jamaican Association of Sugar Technologists (Messrs. M.B. Floro, E.J. Mol, H.B. Springer, C.R.D. Shannon, P.D. Smith, K. White, J.R. Wotherspoon and H.M. Thompson) who wish to acknowledge their indebtedness to the other excellent Manuals of laboratory methods -- Prinsen Geerlig's Chemical Control in Sugar Factories; Official Methods of the Hawaiian Sugar Technologists Association for Control of Sugar Cane Factories; System of Cane Sugar Factory Control of the International Society of Sugar Cane Technologists; Laboratory Manual for Queensland Sugar Mills; Recommended Methods of Chemical Control of the South African Sugar Technologists' Association; and the Cane Sugar Handbook by Spencer and Meade, which have acted as Works of reference in the preparation of this Manual. They are also indebted to Mr. R.E. Lawrence of Tate and Lyle Technical Services for his advice and criticisms and to Mr. J.G. Davies who was primarily responsible for the first Edition.

R.E. INNES on behalf of The Chemical Control Committee of The Jamaican Association of Sugar Technologists April, 1965

PREFACE TO THIRD EDITION

The Chemical Control Committee decided after careful study of the Second Edition (1965) that considerable change and up-dating were needed, due to ongoing development in the Industry.

The presentation and format have thus undergone extensive re-organization. Chapters on Boiler Water Treatment, Metrication and Apparatus have been added; New Methods of Analysis and the Special Analysis Chapter as well as Tables have been added.

As in the previous edition, the aim of this manual is brevity, simplicity and accuracy; only actual operating instructions for performing the analyses are given, theory is to be found elsewhere.

The preparation of this manual has been the work of L.O.O. Brown, W.O. Bailey, D.Y. Byfield and M.McA. D. Dilworth, assisted by Dr. H.C. Bourzutschky, L.R. Johnson, W.O. Ricketts and J. Jaddoo.

References used in the preparation of this manual include Prinsen Geerly's Chemical Control in Sugar Factories; Official Methods of the Hawaiian Sugar Technologists Association for Control of Cane Factories; System of Cane Sugar Factory Control of International Society of Sugar Cane Technologists; Laboratory Manual for Queensland Sugar Mills; Recommended Methods of Chemical Control of the South African Sugar Technologists Association; Manufacture and Refinery of Raw Cane Sugar by Baikow; Cane Sugar Handbook by Meade and Chen.

M.McA.D. DILWORTH on behalf of The Chemical Control Committee of The Jamaican Association of Sugar Technologists

April, 1987

TABLE OF CONTENTS

Chapter I

Definitions

1

Chapter II

Determination of Quantities

6

Chapter III

Apparatus

8

Chapter IV

Sampling

28

Chapter V

Methods of Analyses ..

37

Chapter VI

Special Analyses

..

71

Chapter VII

Boiler Water Treatment ..

85

Chapter VIII

Standard Solutions and Reagents

97

Chapter IX

Calculations and Formulae

106

Chapter X

Time Accounting

116

Chapter XI

Metrication

120

Chapter XII

Lab Management and First Aid

125

APPENDIX/ TABLE INDEX

133

Appendices

134

Tables

139

CHAPTER I

DEFINITIONS

Ash Inorganic residue remaining after incineration. In practice, the proportion of

residue remaining as 'ash' is influenced by the conditions of combustion, so that ash, as actually determined is not an absolute quantity. This term will refer to 'sulphated' ash unless otherwise specified.

Bagacillo Fine particles separated from bagasse for filter aid (or strained from mixed juice

(cush-cush)).

Bagasse The residue left immediately after expressing the juice from the cane.

?Brix The concentration (in grams solute per 100 grams solution) of a solution of pure

sucrose having the same density at the same temperature as the solution being tested. If the Brix is detennined by refractometer, it should be termed Refractometer Brix. The weight of Brix is synonymous with Gravity Solids.

Cane The raw material delivered to the mill, from which sugar is recovered, including

clean cane, trash and other extraneous matter. In factories at which a cane cleaning plant operates, this should be specified as Gross Cane, which, after cleaning becomes Net Cane.

Cush-Cush A mixture of water, juice and bagacillo collected as droppings during milling and

straining.

Condensate Water which has been condensed from steam or vapour liberated from boiling

juices.

Crystal Content The quantity of crystalline sugar present in Massecuites, or magma expressed as a

percentage of brix or total weight.

1

I.

Dilution Indicator The fraction moisture to dry non-pol (sucrose) expressed as a percentage, i.e.

This factor is used to predict the keeping quality of new sugar. Below 40% - keeping quality is good. Above 50% - keeping quality is poor as the probability of deterioration is high. Between 40-50% - keeping quality is doubtful. Dilution Water

The portion of the imbibition or maceration water in the mixed juice. Extraction

(a) (Pol). Pol or Sucrose extracted in the milling plant per 100 Pol or Sucrose in the milled cane. The term extraction will refer to Pol extraction unless otherwise specified.

(b) (Reduced Pol). An expression of Pol Extraction in terms of a standard fibre of 12.5% on cane (mainly for comparative purposes).

Extraneous Matter That portion of the material received as cane, which by arbitrary standards, is

considered not to form part of clean cane. It consists of loose and adhering trash, tops, roots, dirt, suckers etc. Fibre

The dry, water insoluble matter in cane. Filter Cake (mud)

The residue removed from process by filtration. Imbibition

The process in which water or juice is put on bagasse to mix with and dilute the juice present in the bagasse. The water so used is termed "Imbibition Water". Java Ratio

The ratio of the percentage of Pol in milled cane to Pol in first Expressed Juice, i.e.

2

Juices (a) (b)

(c) (d) (e)

(f) (g)

Absolute: All the solids in solution together with all the water in cane. Absolute Juice = (Cane -- Fibre).

Clarified: The juice obtained as a result of the clarification process. It is synonymous with Evaporator Supply Juice when the Filtered Juice is returned to Mixed Juice tank.

Filtered: The combined filtrates from the filters.

First Expressed: Synonymous with Crusher Juice. The juice expressed from cane by the first two rollers of the milling tandem.

Last Expressed: The juice expressed by the last two rollers of the milling tandem.

Residual: The juice left in the bagasse after milling, i.e. (Bagasse - Fibre).

Mixed: The juice sent from the milling plant for further processing.

Losses (a)

(b)

Boiling House: Difference between Pol in mixed juice and Pol Recovered, i.e. (Pol in filter cake + Pol in final molasses + Pol in undetermined).

Total: Difference between Pol in cane and Pol Recovered, i.e. (Pol in bagasse + B.H. losses).

Massecuite The mixture of crystals and mother liquor discharged from the vacuum pan.

Massecuites are classified according to stages of boiling (or descending purity) as A, B and C. Magma

A mixture of crystals and sugar liquor produced by mechanical means.

Milling Loss The Pol to Fibre ratio of bagasse expressed as a percentage.

Moisture

Loss in weight due to drying under specified conditions expressed as a percentage of the total weight of the product being examined.

Molasses

The mother liquor separated from a massecuite. It is distinguished by the same terms as the massecuite from which it was separated, i.e. A, B or C.

Molasses -- Final The molasses from low grade boilings from which no further sugar is to be removed.

3

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