502 
NATURE 
’ 
‘ 
[FEBRUARY 22, I9I7 
Consideration may now be given to the more 
economical utilisation of our coal, and the natural 
course will be to deal first with wastage in production. 
In the past coal-mining has been characterised by the 
little regard which has been paid to wastage of good 
coal, often, of course, through financial considerations. 
Many of the losses in mining coal are unavoidable 
—for example, by reason of the small dirty coal pro- 
duced—but a great deal of really good coal is often 
wasted because it does not pay to bring it to 
bank, 
With the introduction of coking plants, of briquet- 
ting plants, and of sizing and washing plants, the 
amount of small coal wasted has been very materially 
reduced, and the increased price for such prepared 
coals has proved an important factor in the economy 
of coal. 
Turning now to economy in use, with our present 
knowledge of methods of getting power from coal, 
the best utilisation we are likely to effect (by gasifica- 
tion and use directly in, gas-engines) will be about 
equal to 20 per cent. of the available energy. 
Economy in operating can be obtained by more 
attention to combustion, and the combination of the 
purchase of coal on a scientific basis with scientific 
control of combustion leads to very considerable 
economies. 
In the whole scheme of coal economy it will ob- 
viously be desirable to employ the form of plant which 
gives the highest thermal efficiency, for by such plant 
the lowest fuel consumption will be attained; but 
many other considerations besides thermal efficiency 
will be taken into account. It was to gaseous fuel 
that the Royal Commission (1905) looked for the 
realisation of enormous economies in coal consump- 
tion. Since that date, however, the steam turbine 
has developed and, although inferior as a heat-engine 
to the gas-engine, has proved a more serviceable 
power unit for large-scale power production than the 
gas-producer and gas-engine. For power production 
and distribution as electrical energy on a large scale 
the turbine has practically completely supplanted the 
gas-producer in the opinion of engineers. 
Producer-gas plants with gas-engines, however, 
have their proper sphere in the economy of coal, 
and have contributed very largely to economy. 
Another important point is that a class of coal totally 
unsuited to use for steam raising can be employed in 
a producer, so that good steam-raising coal is 
economised. 
The introduction of suction gas plants has also been 
a great advance, because such plants have almost 
invariably been installed in place of moderate and 
small-sized steam plants, the latter being notoriously 
inefficient as power units. : 
There are two very important industrial operations 
where great saving is possible, even although con- 
siderable progress has been made in reducing this 
waste. These are the waste of heat in blast-furnace 
and coke-oven practice. 
The available surplus power from blast-furnaces 
amounts to a very large figure. Approximately, for 
every ton of iron produced, 150,000 cub. ft. of gas 
of a calorific value per cubic foot of go to 100 B.Th.U. 
are obtained. After heating the blast stoves and 
operating the plant with gas-driven engines, a surplus 
of 65,000 cub. ft, may result, this being equivalent to 
an output of about 650 b.h.p. 
The surplus _gas_ available in colse-ovens per ton 
of coal carbonised is about sooo cub. ft., and its 
calorific value about sso B.Th.U. per cub. ft., so that 
a_coke-oven plant carbonising 400 tons per day and 
giving the above amount of surplus gas will, with the 
consumption of 21 cub. ft. per b.h.p., operate a power 
plant with an output of 4000 b.h.p. per hour, 
NO. 2469, VOL. 98] 
| 
Se 
Surplus coke-oven gas is being utilised as a source 
of power for the supply of the collieries, or in connec- 
tion with a “waste-heat’’ scheme, in admixture with — 
producer gas for steel-making, and as supplementing 
the supply of coal gas in the neighbourhood. et atid 
In the field of fuel economy, great as savings would 
be which can_be realised by individual action, they 
are small as compared with what might be realised 
by collective action throughout a district, and the ex- 
tensive scheme which has been in operation on the 
North-East Coast for some years is an object-lesson in 
what can be accomplished. rad 
The underlying principle is to have a uniform col- 
lecting and, therefore, distributing electric system. 
Waste heat from coke-ovens and blast-furnaces, and 
exhaust steam from blowing engines (through low- 
pressure turbines), are utilised continuously at maxi- 
mum electrical output, and the supply supplemented as 
necessary from steam-operated turbine sets at a limited 
number of stations. 
The area covered by the scheme is 1400 square miles ; 
the length of the district (north to south) is seventy 
miles; and the present total horse-power generated, 
343,000. Collieries with an output of more than 
twenty million tons now depend on this supply, and 
show a saving of about 75 per cent. in coal consump- 
tion (equal to one million tons of coal); the suburban 
railways are supplied with electric power for eight 
miles of single track; heavy freight haulage is carried 
out on fifty miles of track; tramway systems are sup- 
plied with current. In addition, lighting is provided 
in towns with an aggregate population of 700,000.” 
Another important feature is the development of new 
industries, notably electro-chemical. 
There can be no question that enormous economies 
are possible on similar lines in the great industrial 
centres, because existing conditions are generally 
favourable. There has been a natural concentration 
of industries and population in the vicinities of our 
coalfields; the principal sources of waste heat—iron 
smelting, with its complement, coke manufacture— 
have developed naturally in the same areas. There is 
the large demand for power for industries, for locomo- 
tion, and for the general supply of heat and light to 
a large population. 
London is in a special and unique position as re- 
gards such a general-power scheme; it is far removed 
from coal-producing districts (at least, until there has 
been considerable development in Kent); it has an 
enormous population and big demands for power, 
although no large individual demands which compare 
with the big industrial concerns in the North; and 
enormous demands for lighting and domestic heating. 
Waste heat is not available in the London area, and 
current would have to be generated at large stations 
situated below London, necessarily on the riverside. 
so as to secure the advantages of sea-borne coal and 
ample water supply. For the most efficient scheme I 
feel convinced that the gas companies and future low- 
temperature carbonising concerns will have to supple- 
ment the directly generated current, the former being 
linked in by utilising surplus coke in producers and 
the producer-gas in gas-engines coupled with genera- 
tors, the latter through their.surplus gas, to be mixed 
with poor producer-gas (possibly the coke-sas referred 
to). The gas companies already have their distribut- 
ing system and market for gas; the low-temperature 
coke will find the best market in the country at hand. 
In this way three important concerns, which would 
handle coal as their main raw material, could be linked 
up through the medium of the future uniform system 
of electricity distribution in the metropolis to the very 
great advantage of the community. providing cheap 
electricity and smokeless fuel, and retaining coal-gas 
with its many advantages. 
