February 9, 1917.

THE COLLIERY GUARDIAN.

277

lent to 2| million quarters of wheat, z.e., an addition of
over 30 per cent, to our present home-grown supplies;
furthermore, the exportation of fertiliser and importation
of wheat required shipping to the extent of 800,000 tons,
and resulted in an aclvense trade balance of £4,574,000.

FUEL ECONOMY.

An interesting discussion followed the reading of the
two papers on “ Fuel Economy ” by Mr. Julius Frith
and Mr. Drummond Paton* at the meeting of the Man-
chester section of the Institution of Electrical Engineers
on the 30th ult.

Mr. T. Roland Wollaston said he had made the sub-
ject his particular hobby, because of his long associa-
tion with boiler house practice generally, and latterly
with the Mend system. Mr. Frith assumed, as a start-
ing point, that the direct-fired boiler ’efficiency was 75
per cent., and the gas-fired boiler efficiency was 80 per
cent. The former was very good; perhaps a little too
good as an average. The latter was very moderate as
things were at present, and extremely so when the true
gas-fired type of boiler came to be designed. So far,
almost all gas-firing schemes had been crude adaptations
of boilers specifically designed for direct firing. Even
under those conditions, efficiencies over 80 per cent, had
been consistently obtained with such ease and low main-
tenance costs as would be a revelation to the average
boiler house engineer — no zig-zag CO2 curves, but a
straight horizontal line at or about 17 per cent. C02 for
days and weeks together, with smokelessness, cleanli-
ness and low labour costs. Mr. Frith’s coke oven pro-
position was expressed in a way which might lead one
to think he advocated putting down coke ovens specific-
ally for firing boilers. Goke ovens were. devised primarily
for making coke, but incidentally they gave by-products,
of which gas was one. That surplus gas might be. used
for the generation of electricity when convenient, but
who. would consider burning 280,000 tons of coal where
22,500 tons would do, or laying out £227,000 for the
purpose? Whence was the coal to come, or where was
the coke to go if the practice became general? In regard
to by-product recovery producers, they were on different-
ground. He was a convinced believer in the economic
possibilities of the combination of such producers with
steam boilers, obtaining substantial rebates through the
recovery of sulphate of ammonia, but Mr. Frith’s figures
for a Mond installation seemed to him misleading. It
was suggested that the ton of coal would produce
135,000 cu. ft. of 150 British thermal units gas, equal to
76 per cent, thermal efficiency. Where was there now,
or ever likely to be, a Mond plant showing such effici-
ency? To take 68 per cent, was being generous. Assum-
ing that figure in conjunction with 80 per cent, boiler
efficiency, the all-round efficiency became

= 54-4 per cent.; and the net coal consumption would be
—sav> 31,000 tons per annum. Mr. Frith
said a Mond producer required for blast two tons of steam
per ton of coal gasified. That was rather over-stating
the case, but he would let it stand. Such steam could
often be obtained as exhaust at collieries and steel works
and the like, but in electrical stations, unless borrowed
from the turbines (which appeared to him, Mr.
Wollaston, particularly undesirable), it would have to be
separately generated and paid for. Mr. Frith said it
would add to the coal gasified 33 per cent., but, iti point
of fact, it would add a great deal more, as would be
seen from the following figures :—11b. of steam from
normal feed would require 1,100 British thermal units or
thereabouts; lib. of coal used at 54-4 per cent, effici-
ency — 6,528 British thermal units, and would therefore
generate about 61b. of steam; therefore, for every pound
of coal gasified, there would be needed 21b. of steam,
or lb. of extra coal. The gasification of that extra coal
required again more, steam for blast, generated by still
more coal, and it was obvious that the total cost gasified
would be given by the geometrical sum :—

< 31,000 , 31.000	-	,

31,000 4- —+ -——— = say, 46,500 tons.

3	32

Yield of Sulphate of Ammonia.

The yield of sulphate from this increased consump-
tion would be proportionate at 4 per cent., say, 1,860
tons, and the capital cost also approximately propor-
tional, say,	x 43 =£36,000. So the balance

J 37

would become :—

Dr.	£

15 % capital and main-

tenance on £36,000.. 5,400
Labour at 2s. per ton 4,650
Reagents at £2 ....... 3,620

Sundry charges........	600

46,50utonsof coal at8s. 18,600

Or.	£

1,860 tons sulphate at

£12 ............... 22,320

1,160 tons tar at 15s.	870

22,500tonscoalat 8s. 6d. 9,600

32,790

Balance, loss......	80

£32,870

£32,870

That was an unfortunate example for the Mond
system. It would be noted that everything hung on
that 2 lb. of blast steam required per pound of coal. He
had held, for many years, that all that extraneous steam
was neither chemically nor physically necessary, and this
was now proved up to the hilt by plants of considerable
size made to the designs of Mr. Quinton Moore. Trials
upon those demonstrated beyond doubt:—(1) Less than
one-third that steam would do; (2) practically the whole
of that steam could be generated by the producer and
outgoing gas (he believed absolutely the whole); (.3) gas
of at least the same heat efficiency and better chemical
composition resulted (i.e., higher CO, lower H); and (4)
the ammonia yield was at least as good. Mr. Frith had
referred to tw-o contributions of his (Mr. Wollaston’s) to

* Colliery Guardian, February 2, 1917, p. 231.

The Engineer on the question. They appeared in that
paper on April 2, 1915, and August 25, 1916, and gave a
fairly full analysis of the subject, with means of correc-
tion for varying values of fuel and sulphate. . He ven-
tured to give the balance-sheet for such a plant, based
exactly on Mr. Frith’s proposals, except that there was
no outside demand for blast steam. In other respects
the figures were in strict ratio :•—■

Dr.	£

15 % capital and main-

tenance on £22,500.. 3,375
Labour at 2s. per ton 3,100
Reagents at £2 ....... 2,480

Sundry charges    500
31,000 tons coal at 8s. 12,400

Or.	£

1,240 tons sulphate at
£12 ................. 14,880

775 tons tar at 15s..... 581

22,500tonscoalat8s.6d. 9,600

25.061

. Balance, gain .... 3,206

£21,855	£21,855

A return of something like 14| per cent, on extra
capital outlay was worth consideration per se, particu-
larly when taken along with reduced labour and main-
tenance, consistency, cleanliness, and smokelessness in
the boiler house. But one might look further. Mr.
Paton outlined the performance of a particular low-
temperature retort plant, which was one of many under
development. He did not know whether it was the best
or not, but it would answer for the purpose of illustra-
tion.

Low-Temperature Gasification.

Sulphate of ammonia was probably the highest value
residual, but they did not know definitely whether it
would always remain so, having in view the possibilities
in fixing atmospheric nitrogen. It was obviously pos-
sible by that low-temperature system to recover the high
yields of workable tar, oils, spirits, etc., leaving the
whole of the nitrogen in the residual coke or coalite,
which wais an ideal free-burning producer fuel, and at
once freed one from all the troubles associated with
ordinary producer working. He agreed with Mr. Paton
that we were within measurable distance of a combina-
tion of low-temperature and producer work for boiler
firing (or for gas engines if preferred), elastic enough to
enable one to work for the highest respective yields
of those products, particularly in demand at any given
period, and so arranged that the transference in the
double process would involve but trifling heat loss. With
regard to the gas versus steam engine competition, he
would only say that, on an electrical station scale, his
own instincts pointed to the steam turbine.

Mr. Hunter said he had a lot to do with the produc-
tion of gais from coal, especially with the Moore pro-
ducer, in Glasgow, where they had made dozens of
experiments trying to effect improvements. They
worked it without any external steam at all, but that
was not yet a commercial success. No doubt that
result would be reached in a short time. An important
point to remember was that if the object was to produce
sulphate of ammonia, the more water they put in, the
larger the proportion of hydrogen, the better the yield
would be, but for boiler firing a gas was wanted which
contained a large proportion of carbon monoxide, so ns
to. reduce the amount of latent heat which passed up the
chimney. It was very desirable to have a trained man
in charge of the boilers. In one case, he gave instruc-
tions for a couple of days ait the work, and then replied
daily to the reports he received. At the. end of three or
four weeks the engineer in charge was able to run the
boilers regularly to the full capacity, and his wages were
only slightly in excess of what he would have received
for ordinary work. It was a cheap method of effecting a
large saving, and he was amazed that many owners to
whom it was suggested were very loth to adopt it. It
was cheaper than a recording instrument, which required
the attention of a man. From the analysis of gas, one
could .gather what would be the result of combustion in
the boiler. It mattered little what the type was; the
essential factors were the same in all except the radia-
tion losses, which in Lancashire boilers were estimated
at 10 per cent., and in water tube boilers at 5 to 2-J- per
cent. They could not effect much saving in efficiency
by designing new types. Quickness in firing was another
matter. Boilers could be made, to fire more quickly than
the Lancashire boiler did when using gas. Knowing
beforehand what the quality and pressure of the gas
would be, the plant could be kept at a proper efficiency
if provision was made for controlling the effects of
changes in those factors. At this end of the problem
satisfactory progress had been made. With regard to
low-temperature distillation, he should be glad to see a
plant in actual operation. Even if it were only one unit,
it would enable an idea to be formed as to how the whole
scheme of the combination would work out.

Advantages of Large Units.

Mr. Watson said it was very fitting these papers
should be given at Manchester, because there was pro-
bably no other area in Great Britain where larger quan-
tities of fuel were used for industrial purposes. Fuel
economy was a national question of the utmost import-
ance. The country’s resources were not inexhaustible,
and must be made to. go as far as possible. In the first
place, good fuel could be utilised to greater advantage.
Large quantities were now being burnt inefficiently;
there were hundreds, perhaps thousands, of Cases where
7. 8, or even 101b. were consumed to obtain as much
•electrical energy as could be got from 2| lb. under proper
conditions. That was little less than a national disgrace.
Small plants must not continue to work in an unecono-
mical manner. By centralising into larger plants, much
better’ results would be obtained. In the second place,
what was to be done with the millions of tons of poor
dlass fuel which was now left in the mine or dumped at
the top? As our coal resources dwindled, it would
become increasingly imperative to utilise these lower
grades, and undoubtedly it would be done by means of
plants producing gas, coke, and by-products. Not the
least important of these was sulphate of ammonia. The

future demand for it as a fertiliser could hardly be
measured. It had been suggested that the facilities for
its production were so- great that a slump in price was
inevitable, but he did not think that was borne out by
recent enquiries. He regarded Mr. Frith’s scheme of
an industrial district, grouped around a colliery, as quite
Utopian. The capacity of any pit could be gauged, and
the supply must sooner or later become exhausted. •
What was going to happen then to the millions expended
upon the locality? Mr. Frith provided a generating
station of 1,200 kw., which was to use 2|lb. of coal per
unit, and turn out 20 million units per annum, the load
factor being 25 per cent., and the over-all thermal
efficiency 11'4 per cent. Some very large steam-driven
stations in the States were getting 16 or 17 per cent.,
and there was no doubt that, as the sizes of units which
could be usefully employed grew larger, similar effici-
encies would be obtained quite easily in this country.
In fact, he knew that 13 to 15 per cent, was now being
obtained in quite a number of cases. With such
efficiencies, the cost of the coal per unit sold became
quite small. With coal at 8s. per ton, as taken in the
paper, and a consumption of 1 f to 2 lb. per unit, the cost
would be in the neighbourhood of 0'08d. per unit. There
was not a large margin for saving. He was also very
dubious about the estimate of £225,000 for construct-
ing 150 ovens and subsidiary plant, but he was not in a
position to judge whether it was right or wrong. When,
however, Mr. Frith assumed that 10 acres of land would
cost £500, and the railway siding to deal with the best
half of a thousand tons would cost £1,500, he was getting
into the region of romance. It could not be done in
this country. In his view, the distillation of coal must
come on the ground of economy, and it would lead to the
use of gas in the boilers and also of a very large quantity
of coke. Probably there would be gas-fired, coke-fired,
and, to some extent, coal-fired boilers in one and the
same generating station.

Residuals.

Mr. Clayton said his knowledge of the subject was
confined to the residuals. His firm were the first in
England to instal the Moore producer, but unfortunately
they did not send samples of the fuel to the makers,
and much trouble was caused by the very bituminous
nature of Lancashire and Yorkshire coal. It was
extremely difficult to use such coal with a low-tempera-
ture producer, because the retorts got into a sticky con-
dition. Scotch coal was more suitable. In the manu-
facture of coalite, the main trouble had been the sticky
condition into which the coal got. They were com-
pelled to buy Nottingham' coal, which was not very
tarry, and.the results obtained had been perfectly satis-
factory; the guarantees were fulfilled in every respect.
People must not run mad on residuals.' There seemed
to be an idea abroad that one had only to get the resi-
duals to make a, fortune; but it must be borne in mind
that as the price of coal went up the difficulty of profit-
able working materially increased. To take slack at
2s. 6d. a ton (which used to be the pithead price), put
it into the producer plant, and get 9s. worth of
ammonia sulphate, was a working proposition., but it
was quite a different matter if the coal cost 15 s. a ton,
and 30 to 40 per cent, was thrown away. He entirely
disagreed with Mr. Paton’s prices. Of course, the pre-
sent market rates were absurd; the basis of any esti-
mate must be pre-war prices. For motor spirit, they
used to get 6d. per gal., and he thought 9d. was the
highest it should be put at. Middle oils had no value,
except as fuel, and he put the maximum at 4d. Heavy
oils he put at 3d. Cresylic acid was a special product,
and the big outlet foir it was as a disinfectant. Before
the war, the price was often so low that it was not taken
out separately. Ito quantities so large as those esti-
mated, it must be taken at its burning value. Pitch he
put at 30s., an advance of 10s. on the pre-war price.
Sulphate of ammonia was £8 per ton before the war. A
serious situation arose from the invention of a process
for manufacturing ammonia from the air, or, rather,
from hydrogen and nitrogen, at a cost of £5 or £6 a ton.
Probably 300,000 tons a year was being made in Ger-
many by this process, and it was reported—with what
truth he could not say—that it was intended to increase
the quantity to a million tons per annum. In America
a great number of coke ovens had been put down., and
in Norway and elsewhere large, amounts of cyanides and
nitric acid were being made. It seemed to him impos-
sible that sulphate of ammonia should be anything like
£18 a ton: it would be wiser to put down £10. Taking
thb thing as a whole, he reduced the £500,000 for resi-
duals to £325,000. A reduction of £175,000 must
seriously affect the financial aspect of the scheme. He
did not say such schemes were wrong in principle; he
agreed that coal ought to be treated in some way to
recover the by-products, but it must be done on sound
financial lines. Otherwise, some miscalculation might
result in a good scheme being turned down, and right
development prevented.

The Chemists’ Point of View.

Mr. Owles said his point of view was that of the
chemist. Research was absolutely necessary. The
burning of fuel seemed a simple matter, and when a man
found a fire burning well or badly, he was apt to base
his opinion upon the fact, and say the coal was good
or bad accordingly. That did not necessarily follow.
When they got smudge in a dry slack, the efficiency
dropped remarkably. It was impossible to get the same
efficiency out of a boiler with such fuel as with dry nuts.
Economisers were used extensively in the States, where
coal with very high volatile contents was consumed, but
they could not be utilised in this country to the same
extent. With some coals, the boiler efficiency might be
increased 2| per cent. There was a good deal of ignor-
ance concerning economisers. Some people were apt to
say they were only common salt, or -borax, or calcium
chloride, but the economy was brought about because