Boiler Efficiency and Safety: A Guide for Managers, Engineers and Operators responsible for Small Steam Boilers

147 Pages·1981·12.44 MB·English

Boiler Efficiency and Safety
Some potential savings from following
advice in this book
• First, enhanced safety saves life and health
• Savings of S to 10 per cent on fuel costs are often possible at little or no cost
• Savings of up to 30 per cent on fuel costs may be possible by using new steam
generating or steam-using equipment
• Target boiler efficiency with new package boilers can be up to 85 per cent at
maximum continuous rating
• Off-line time can drop drastically, giving production continuity and reduced
labour costs
• Repair costs can drop by thousands of pounds a year
Only you can achieve savings of this kind at your plant, but the information in
this book can help.
Boiler Efficiency and Safety
A Guide for Managers, Engineers
and Operators responsible for
Small Steam Boilers
Edited by
W. S. Robertson
Contributors
H. M. Ashton
G. Datschefski
A. J. R. Isaacs
C. S. Macdonald
W. S. Robertson
K. C. Salooja
E. G. White
M
9
© Esso Petroleum Company, limited 1981
Softcover reprint of the hardcover 1st edition 1981
All rights reserved. No part of this publication may be reproduced or transmitted,
in any form or by any means, without permission.
First published 1981 by
THE MACMILLAN PRESS LTD
London and Basingstoke
Associated companies in Delhi Dublin
Hong Kong Johannesburg Lagos Melbourne
New York Singapore and Tokyo
Typeset in 10/12 Press Roman by
STYLESET LIMITED
Salisbury · Wiltshire
ISBN 978-1-349-04792-5 ISBN 978-1-349-04790-1 (eBook)
DOI 10.1007/978-1-349-04790-1
This book is sold subject to the standard conditions of the
Net Book Agreement.
Contents
Preface vii
Safety 1
2 Types and selection of fuel oils 6
3 Combustion processes and monitoring 13
4 Combustion in practice 24
5 Water treatment 39
6 Boiler operations 56
7 Maintenance 71
8 Efficient use of steam 109
9 Training courses and material 121
Index 137
Preface
This book covers practical steps to achieve fuel - and money - savings in one
specific area: for package steam boilers of up to about 10 MW output. The
authors know its content achieves savings - they have achieved them in their
own organisation.
The book is written principally for managers responsible for automatic steam
boilers, and for supervisors and operators who run them. It gives managers the
background data that they need to ensure their equipment is operated at maxi
mum efficiency. It also gives operators the basic information they need to carry
out efficient boiler operation. The book is not primarily intended for professional
engineers: they are likely to know it all already, although some may appreciate a
reminder of a few basic points.
The content of the book springs from a programme on boiler efficiency and
safety introduced in Esso Petroleum Company marketing plants. That programme
for plant managers and for operators saved £60 000 in fuel costs in its first year.
The Boiler Efficiency and Safety Training programme was later made generally
available to industry as an audio-visual presentation on filmstrip/tape and on
video.
However, since audiovisual techniques are not always applicable, this book
has been written, mainly by those involved in the original programme, to expand
on the information in the programme and to make it more widely available.
The book begins with a discussion of vital safety factors. It then briefly
covers the types and selection of oil fuels. Although the book as a whole uses
oil-fired boilers as examples, only chapter 2 on types and selection is exclusively
concerned with oil fuel - much of the remainder applies equally to gas firing
and, to a lesser extent, to solid-fuel firing.
The book deals in some detail with the theory and practice of combustion
and of water treatment. This is followed by a chapter on boiler operation and a
comprehensive chapter on maintenance. The chapter on steam use stresses the
important but sometimes overlooked point that savings here can be many times
as great as savings in steam generation. Finally, there is a chapter on training
courses and information for operators and managers.
The authors gratefully acknowledge permission from Esso Petroleum Company,
Limited to publish their contributions. However, responsibility for the content
and for any errors that may have persisted in it is theirs alone.
Acknowledgements
The authors gratefully acknowledge provision of illustrations by the following
organisations
Taylor Analytics
NEI Thompson Cochran Ltd
University of Leicester audio visual unit
Bestobell Mabrey Ltd
Nu-way Heating Plants Ltd
Hamworthy Engineering Ltd
Spirax Sarco Ltd
1 Safety
Oil or gas-fired package boilers are frequently described as 'fully automatic',
giving the impression that once started they can be left to operate without
supervision. This is possible, but dangerous. It could, in the extreme, cause a
boiler explosion. It would certainly make the boiler operate well below its
optimum efficiency. No boiler ought to be run without a qualified operator
being on the site. He need not be in the boiler room all the time, but he should
be where he can hear an alarm and act on it. It would be more accurate to
describe package boilers as being automatic only to the extent that they are
fitted with controls to maintain combustion efficiency under varying load
conditions and to control water level, and that this enables the amount of
attendance to be reduced.
Guidance Note PM5 from the Health and Safety Executive states 'Experience
has shown that the incidence of damage or explosion caused by low water
conditions has been higher pro rata with boilers having fully automatic level and
firing controls than with those which are manually controlled'. It follows then
that safe package boiler operation can only be achieved by working to a system
atic, closely controlled operating plan.
Boiler safety cannot be separated from boiler efficiency; there are close ties
between the two. There are also links with the maintenance and repair aspects.
Figure 1.1 shows these links and their connection with operational practices.
For example, the safety of a boiler will depend on the standard of maintenance
and this in turn will be influenced by the way the unit is operated.
The complexity of a modern package boiler makes the statutory boiler
inspection as covered by the Examination of Steam Boilers Regulations 1964
less than adequate. A more detailed three-part check is recommended, including
such items as the control cubicle with its associated wiring, the motor starters,
and so on.
Hazards from operating package boilers can arise on the water side from low
water level, poor quality feed water or high steam pressure. On the fire side they
may be caused by defects in the firing equipment and controls. Low water level
is dangerous in any boiler. In particular, modern package boilers contain little
water in relation to their steaming capacity, and failure of the water feed system
2 Boiler Efficiency and Safety
Safety
Energy Maintenance and
conservation repairs
Figure 1.1
could quickly cause a serious accident from furnace tube collapse. To a lesser
degree, perhaps, there is the danger of an explosion from tube over-heating
where scale build-up has insulated heating surfaces from the water, so causing
the tube material to soften and become deformed under the steam pressure. In a
similar way, condensate contaminated with on can cause local over-heating.
Fire risk must also be considered; provision for testing and maintenance of
fire valves and associated equipment is essential for continued safe operation.
The boiler specialist
Energy conservation is not, of course, confined to the boiler house. The greatest
savings in fuel are likely to be made where heat is used, on the process plant.
Here there can be conflicting interests between the production and service sides
at a factory or installation. One solution is to set up an organisation where a
single person (with deputy) is made responsible for the technical aspects of both
the total steam-raising and steam-using operations within the boiler house and
on the plant. He is described in this book as the 'boiler specialist'.
The boiler specialist is a suitably trained employee who is responsible for all
aspects of boiler operation and safety. Each organisation will have its own ideas
about the appointment, but certainly it could be covered by a senior plant
operator, a plant fitter, a technician or a shift or maintenance supervisor. The
advantages of undivided responsibility for this important area are clear, since a
problem of shift operation is that the boiler plant may become no one's respon
sibility and be neglected. It would be the boiler specialist's responsibility to
carry out the duties which can be summarised in table 1.1 , so avoiding a possible
random approach that might lead to unsafe as well as inefficient boiler operation.
This total operation would include setting up a system for routine checking