PETROLEUM AS FUEL
So much has been written of late as to the use of petroleum as fuel
for the purposes of steam-raising, that the reader is bound to be more
or less _au fait_ with the subject. It is, of course, one of vast
importance, and during the next decade is certain to receive far more
consideration than it has hitherto done, owing to the general desire
that our coal wealth shall be conserved as much as possible. Given the
one allowance that oil fuel can be procured at anything approaching a
reasonable figure--and there is no reason why, in normal times, this
reasonable price should not be prevalent all over the world--then
petroleum offers many advantages over its older competitor, coal. The
ease with which large quantities can be handled, the simple method of
operating anything which is fired by petroleum as fuel, and the fact
that its heat-giving units are far higher than those of coal, will ever
be the chief factors governing its popularity.
Many years ago, fuel oil made its serious début, but at that time the
supply of the product was very uncertain, and, consequently, progress
in passing from the old to the new form of power-raising was slow.
To-day, however, matters have materially changed. The crude oil output
has been immeasurably increased, and many fields whose production of
crude oil is essentially suited for fuel purposes have been opened up.
In this respect, the oil-fields of Mexico have no parallel, and it is
recorded that, once these fields are provided with adequate storage and
transport facilities, they can easily supply the whole of the fuel oil
necessary for the world, and at the same time have immense quantities
to spare.
But, though the subject of petroleum as fuel has aroused much attention
for some years, there is still an erroneous idea prevailing as to what
really is fuel oil. A word or two on this question will, therefore, not
be without interest. Fuel oil is that portion of crude oil which is
incapable of giving off by the process of ordinary distillation those
lighter products of petroleum known as motor spirit, illuminating oils,
or lubricants. It is, in a word, the residue of distillation which is
unsuitable for refining purposes. It represents a black, tarry liquid,
and is, of course, minus those fractions that go to produce the refined
products. Many there are who refer to crude oil as fuel oil, but this
is a misnomer, though crude oil, in many instances, is utilized for the
purposes of fuel. In this chapter, however, when I speak of fuel oil,
I am referring not to the crude oil as it comes from the ground (and
which has a comparatively low flash) but to the article of commerce,
the residue of distillation, which is the real article--fuel oil.
The headway which fuel oil has made during the past few years has been
remarkable, though it is safe to say that its general use is still in
its infancy. In no matter what capacity it has been tried as a heating
or steam-raising agent, it has proved itself capable of withstanding
most successfully the most stringent tests, and has convinced all who
have given the question serious consideration that it holds numerous
advantages over coal, yet has no drawbacks. Perhaps the most recent
impetus which has been given to the use of fuel oil is that following
the introduction of it, and now its general adoption, throughout the
units composing the British Navy. On land, however, it has for some
years achieved marked distinction. Especially is this the case in
regard to its use on locomotives, the United States railways alone
consuming last year over 6,000,000 tons of fuel oil. In the realms
of industry, fuel oil, too, is claiming the attention of those large
industrial establishments, and to-day is largely used for creating
intense heats, such as are necessary in hardening, annealing, melting
and smelting, rivet heating, glass-melting, etc.
Let me first of all refer to the use of oil fuel for marine purposes.
Fifteen years ago, its use was very strongly advocated by Sir Marcus
Samuel, Bart., for marine purposes, and he approached the British
Government in an endeavour to get it taken up. Matters moved very
slowly, but eventually oil fuel was adopted, and Admiral Sir William
Pakenham asserts that it was due to the unceasing efforts of Sir Marcus
Samuel that the Admiralty vessels constructed during the war were
oil burners. The largest of this new class of vessels is the _Queen
Elizabeth_. Oil fuel is now largely used in place of coal on our great
liners, vessels like the _Aquatania_ and _Olympic_ having gone over to
its general use.
There are, of course, many reasons which have commended fuel oil to
the experts as a substitute for coal. In the first place, inasmuch
as one ton of fuel oil is equal to more than one-and-a-half tons of
coal, the radius of action of units fitted for utilizing fuel oil is
increased over 50 per cent.--I speak from the point of view of bunker
weight. Again, one ton of oil occupies considerably less space than
an equivalent weight of coal, while this advantage can be materially
increased--as is now the usual practice--by carrying the fuel oil
in double-bottom tanks. Then the bunkering question is one of vital
moment. Fuel oil can be taken on board under far cleaner conditions,
and at a greatly accelerated rate, than would be possible with coal.
There is no arduous manual labour required. Once the hose connections
have been made, the fuel oil is pumped on board at the rate of hundreds
of tons an hour, and a few hours suffice to re-fuel our largest
battleship. But it is when bunkering at sea is required that fuel oil
further emphasizes its immense advantages. This question was some years
ago one of the problems of naval strategy: to-day it is regularly
carried out in the simplest possible fashion, hose connections to a
standing-by oil tanker being all that is required.
Another advantage of fuel oil is that materially increased speed can
rapidly be attained, for, with fuel oil fired furnaces, the ship’s
boilers can be forced to nearly 50 per cent. above normal rating
without that great strain on the personnel which would be essential
in burning coal under forced draught. Then there is the great saving
of labour effected when burning fuel oil, the stokehold staffs being
reduced by quite 90 per cent. The fuel oil is automatically fed to the
furnaces and mechanically fired, the maximum heat of the oil burners
being attained within a few minutes of starting. But the absence of
smoke when the battleship is proceeding at full speed is, perhaps, one
of the most important advantages which the use of fuel oil gives to
the units of the fleets employing it. The emission of dense volumes of
smoke, which are ever present on a coal-fired vessel, is quite absent
when fuel oil is used, and this advantage is twofold, for not only does
it prevent the giving away of the location of the battleship, but it
also renders its own gun-fire more efficient.
The advantages attendant upon the use of fuel oil for naval vessels
are, in the main, also strikingly apparent when oil is adopted for
the mercantile marine. It is many years ago since the oil tankers of
the “Shell” Transport and Trading Company, Ltd., commenced to do the
voyage regularly from the Far East to this country and back without
an intermediate port of call. To-day, practically every oil tanker
afloat burns fuel oil. But, of recent date, fuel oil has reached wider
application by reason of its being adopted on many cargo and passenger
vessels, and, had the European War not considerably hampered ordinary
shipbuilding construction, we should have seen ere this a number of
the largest vessels crossing the Atlantic exclusively running on oil.
In fact, arrangements have been made whereby many of our Transatlantic
lines will operate exclusively on fuel oil, which will be taken on
board in the United States.
[Illustration: TAKING OIL FUEL SUPPLIES ON BOARD]
My friend, Mr. J. J. Kermode, of Liverpool--the well-known fuel oil
expert--has taken the most prominent part in calling general attention
to the immense superiority of fuel oil over coal, and it is due to
this gentleman’s untiring energies that not only does our Navy to-day
use fuel oil to such an extent, but that those responsible for ocean
passenger transport have taken the matter up so seriously. There are
three general headings under which fuel oil use will affect transport
costs. They are as follow: (_a_) by increased passenger or cargo
capacity, (_b_) by increased speed, and (_c_) by a great reduction in
running costs. As to the increased capacity, I have already shown that
fuel oil can be stored in considerably less space than coal, and the
simplicity of both bunkering fuel oil, and using it on vessels, has
also been touched upon. With reference to the increased speed which
vessels utilizing fuel oil can attain over those running on coal, I
have a concrete example in front of me. Two sister ships of the Eagle
Oil Transport Company--the _San Dunstano_ and the _San Eduardo_--each
of 9,000 tons deadweight capacity, are fitted to burn coal and fuel
oil respectively. Upon a trip carried out under careful observation,
the weight of fuel consumed worked out as two to three in favour of
fuel oil, while the indicated horse-power developed showed an 18 per
cent. improvement in the case of the oil-fired vessel. But the striking
fact of the comparison is that the _San Eduardo_ made the round voyage
to Mexico--out and home--eight days quicker than the other, this
additional speed being solely due to the fact that with fuel oil it
was possible to maintain consistent speed throughout the voyage--an
impossible matter when coal is consumed. If space permitted, I could
enumerate many cases where the results in favour of fuel oil are
even more strikingly apparent, but I will content myself by briefly
referring to calculations made by Mr. Kermode, based upon voyages of
our largest liners: they are sufficiently interesting and suggestive
to record here. On an average, says Mr. Kermode, to maintain a speed
of 25 knots, 5,500 tons of coal are consumed upon the voyage between
Liverpool and New York by one of the mammoth liners; or 11,000 tons for
the round trip. Some 3,300 tons of fuel oil--which could be stored if
necessary (and as will frequently be done in the future) in the double
bottom of the vessel--would, by automatic stoking, do even more work
than 5,500 tons of coal. Calculating the daily consumption of 600 tons
of coal now used for 24 hours, this represents about 2,000 tons less
fuel on a five days’ trip, land to land run, or 4,000 tons less, out
and home. The utilizing of the vacant space thus saved for merchandise
would bring in a very handsome income. Of the 312 firemen and trimmers
now employed for a coal-fired liner, 285 might be dispensed with,
and occupation found for them under healthier conditions ashore,
say in handling the additional cargo which would be carried. The
saved accommodation in this respect could be allotted to third-class
passengers, of whom at least another 250 could be carried. Our mammoth
liners are fitted with 192 furnaces in order to produce 68,000
horse-power (as was the case of the _Mauretania_ and the _Lusitania_),
and, on the assumption that thirty-two fires are cleaned every watch,
10,000 indicated horse-power is lost every four hours through burning
down and cleaning, a quite unnecessary operation with fuel oil. Figures
such as these show the startling possibilities of fuel oil for marine
purposes.
[Illustration: TYPICAL LIQUID FUEL BURNERS
THE KERMODE STEAM BURNER]
[Illustration: KERMODE’S AIR JET BURNER
In the steam burner, the oil enters through B, the valve G
giving it a whirling motion. The steam goes round the cone A.
_F_ is the air cone, the amount of air being adjusted by the
openings D by means of a perforated strap E. In the air jet
burner the oil enters at A. The previously heated air enters at
the branches B and C, and as the air passes C it meets the oil
as it passes the control valve operated by E.]
But it is on land, as well as on sea, that we find fuel oil rapidly
making headway, for, as far back as 1889, hundreds of the Russian
locomotives went over to the burning of a petroleum residue. This
was the first practical application of fuel oil for railway haulage.
To-day, nearly 50,000,000 barrels of fuel oil are consumed annually
by the various railroads in the United States, and, according to
the official figures I have of the total mileage of fuel oil for
the past twelve months, the United States oil-burning locomotives
did journeys aggregating over 145,000,000 miles. Mr. Hall, of the
American International Railway Fuel Association, is responsible for the
statement that, owing to the fact that the steaming capacity of the
engines is materially increased, a locomotive running on fuel oil can
haul a load of considerably greater tonnage and at a much increased
speed than would be possible with a coal-fired engine. Many Continental
railways use fuel oil rather than coal; the Roumanian and Austrian
State Railways, the Western Railway of France, the Paris and Orleans
Railway, being a few of the principal.
So far as England is concerned, the use of fuel oil has not made great
headway, for the reason that, while on the one hand, the majority of
our great railway systems pass through the coal-producing fields, there
has, on the other hand, until recently been an absence of organization
for the supply of fuel oil. The Great Eastern Railway many years ago
successfully ran oil-fired locomotives.
It is evident that oil fuel will be increasingly used in the future for
locomotive purposes, and at the time of writing--December, 1919--the L.
and N.W. Railway are carrying out experiments on express engines, with
a view to being able to some extent to discard coal.
In our industrial life of to-day there are a vast number of instances
where fuel oil is rapidly displacing coal: the oil-fired furnace has
been brought to a stage of perfection, and is being extensively
and increasingly employed both in this country and abroad in regard
to metallurgical and industrial processes. Without going into detail
respecting the numerous spheres in which the new fuel finds profitable
employment it is safe to say that these are being extended every year.
[Illustration: OIL FUEL FOR MARINE PURPOSES
Arrangement of heaters, filters and pumps for burning oil
fuel for marine purposes. The installation is that of the
Wallsend-Howden pressure system.]
A wealth of inventive effort has been bestowed in the perfection of the
burners employed to consume fuel oil. Leaving aside for the moment the
principles governing the use of oil in the internal combustion engines
of the Diesel or semi-Diesel type, fuel oil used for the production
of power is introduced into the furnace in the form of a spray, this
being accomplished by atomizing the oil in its passage through a
specially designed burner. Of these burners, there are numerous makes
upon the market, each of which possesses its own characteristics and
advantages. The one feature common to all fuel oil burners is the
arrangement for atomizing the oil fuel into a fine spray, so that
each particle of fuel shall receive sufficient oxygen to ensure its
complete combustion. Theoretically, it requires about 14 lb. of air to
effect the combustion of 1 lb. of oil, and on the thorough combustion
of the fuel oil depends the efficiency of the furnace. There are
three distinct methods by which the atomization is brought about, and
each of these means possesses its advantages and limitations. By one
method, the fuel oil is atomized by the use of steam; by the second
method, compressed air is used; while a third system--that of applying
pressure to the oil supply itself--is sometimes adopted. Steam is the
method usually employed for stationary boilers and locomotives, for it
is the simplest to manipulate, and does not call for the employment
of auxiliary apparatus in the shape of air compressors or oil pumps,
but most industrial oil furnaces work on compressed air, which gives
exceptionally good results. There is no doubt that, with the use of
compressed air, say admitted at a pressure of 80 lb., a saving in
fuel oil is shown over using steam at similar pressure, but the cost
of the compressing plant, which must be taken into consideration, is
sufficient to wipe out the greater part of this advantage.
[Illustration: THE “SCARAB” OIL BURNER]
With respect to the use of the fuel oil direct under pressure, this
system generally involves the heating of the fuel oil, as well as
its filtration, the fuel being supplied under pressure by means of
pumps. The system is extensively employed at the present time on
marine boilers operating with forced or induced draught, and, in this
connection, the Wallsend system stands pre-eminent.
Since writing the first edition of this little volume considerable
advance has been made in connection with the use of oil fuel for
general power-raising purposes, and much of this expansion has been
consequent upon the introduction of a new burner--the “Scarab”--which
is here illustrated. It is the invention of Lieut.-Col. Macdonald, and
is the outcome of the war. When the Lieut.-Colonel was on service in
Mesopotamia, he recognized the possibilities of oil fuel, for while
wood and coal were being transported from India at great cost, oil was
running to waste on the neighbouring fields of the Anglo Persian Oil
Company. The Lieut.-Colonel therefore introduced a method of cooking
by oil fuel, and immediately on his return to England he carried out
experiments which led to the introduction of the “Scarab” burner. It
is a simple contrivance, and is practically fool-proof, since there
are really no parts to get out of order. The oil fuel flows through a
tube by gravity, while another tube carries air compressed to about
10 lbs. pressure. The oil and air meet some inches distant from the
mouth of the burner, and the combustion of the fuel, which is turned
into a finely atomised spray, is complete. Experiments have been made
with the burner for domestic purposes, and it has been adopted already
in several London hotels for cooking purposes, though its general
application is practically unlimited.