230

THE COLLIERY GUARDIAN.

February 1, 1918.

was being cleaned out, as it would only work for about
three months before being blocked up with pitch. He
therefore came to the conclusion that a temperature
of 130 to 130 degs. was far too high; and he subse-
quently found on another plant, where the conditions
were slightly different, that with an initial tempera-
ture of 115 degs., and an outlet of about 105 degs., it
was still possible to get maximum results, and keep the
creosote oil free from water, or, at any rate, within
0-5 per cent. Then there was the question of the com-
parative value of the crude benzol. From the graph,
and from statements made in the paper, it appeared
that the value of 63 per cent, crude benzol was practi-
cally as good as 65 per cent. His experience was that
the 63 per cent, crude benzol might be better than that
at 65 per cent., quantitatively. They might get 63 per
cent, test in the retort, but that did not give them any
idea of the percentage of the benzol, toluene, and
xylene. It might be that the 63 per cent, was due to
an excess of xylene and toluene, and in that case the
value of the 63 per cent, would b.e higher than the 65
per cent, containing a higher percentage of benzene.
That, in his opinion, was the strongest argument
against the retort test for the value of benzol, and he
thought it should be sufficient to strike it out alto-
gether. It did not matter much where people were dis-
tilling their own crude benzol, but it mattered a great
deal if one was selling a tank at 63 per cent, which he
knew was better value than a 65 per cent., and yet
had to make a corresponding reduction in the price of
the 63 per cent. He could state from actual experi-
ence that, on a plant where 63 per cent, benzol was
made, it was actually better than a 65 per cent. When
they were out for the highest possible yield, in the
interests of the country, they would get a far greater
increase at 63 per cent, than at 65 per cent. If at
65 per cent, they got 800 gals., and reduced the condi-
tions of the plant to produce a 63 per cent, benzol, the
increase would be more than the 1 gal. per 100. His
experience led him to state emphatically that the
retort was not a reliable test, and never ought to be
used, but should be substituted by a quantitative test,
something on the lines of the Government test.

Mr. J. A. Wilson (Staveley) bore out the views of
previous speakers as to the quality of crude benzol as
determined by the retort test, and in further confirma-
tion quoted from the recently published paper by Dr.
Spielmann and Mr. Petrie, and gave figures arrived at
in his own experience. In the case of his own benzol,
65 per cent, at 120 degs., a series of samples were taken
over several days, and very carefully graduated, follow-
ing out practical working to the extent of fraction-
ating before washing. In the first case, from 65 per
cent, crude he got 68 per cent, rectified products (in
his own practice he had from 65 per cent, crude got,
some years ago, from 70 to 72). He also had tests
made with some samples offered by merchants. A
sample which tested 54 per cent, at 120 degs., and then
was carefully rectified in the same way that the pre-
vious samples had been, only yielded 60-3 per cent, of
rectified products, but the loss on washing was 24| per
cent.—there was a large proportion of unsaturated
bodies present. From results like that, one could not
possibly estimate the value of crude benzol on retort
tests. Another sample tested 43 per cent, at 120 degs.
yielded 65 per cent, of rectified products. Of course,
there was more of the higher fractions there. Another
sample, 66 per cent, at 120 degs., only showed 60| per
cent, of rectified products; the loss on washing in that
case was 20 per cent. That he thought quite bore out
what had been said with regard to the unreliability of
retort tests.

Mr. George Chrisp praised the authors for the work
they had undertaken, and particularly with regard to
the much-discussed chart of the value of benzol. He
thought, however, that as long as the constituents of
the benzol varied in the proportions, and as long as
they were sold at different prices, no fixed graph could
be given. With regard to water in the oil, they ought
to bear in mind that some oils would hold a lot more
water than others, without serious detriment. With
regard to the saturation point of benzol, the best plan
was to make the test approximate to working condi-
tions as much as possible, on each particular plant. He
took it that Messrs. Haigh and Lamb were referring to
their own particular plant, and in arriving at the
figure of 2 per cent, saturation, they had presumably
taken the test with the final temperature somewhat
approximating that of the still on which they were
working, probably 160 degs. Cent. But 2 per cent,
saturation at that point was to his mind rather low,
unless the condition of the plant warranted the making
of oil at that particular strength. On the conditions
of his Own plant, 2 per cent, would be very low, because
the plant was normally short of steam and cooling
water, and one had therefore to fix the saturation point
in the oil to accord with other things, such as the
volume of steam and cooling water available. It was
quite natural to assume that, with a saturation of 2 per
cent., one would require a great deal more steam, and
a great deal more cooling water. Perhaps Mr. Haigh
would later on tell them exactly what he meant by the
2 per cent, saturation.

Mr. George Taylor (Silverwood) added his congra-
tulations, and said he would like to have a little infor-
mation concerning the mechanical construction of the
sill—its diameter, the number of bells, the kind of
superheater. There was, to his mind, no reason why
the ordinary benzol still should not be heated by dry
steam to every tray. Stills here also seemed to be
somewhat taller and less in diameter than in other
places, and he was not sure that that was an advan-
tage. He thought that with a still disproportionately
tall in relation to its diameter, there was a condensing
action in the top — a dephlegmating action — which
again was detrimental in stripping the oil; and, after
all, what they were out for was to get benzol from the
oil, rather than to make a very high-class first pro-
duct; they could get that afterwards by dephlegma-
tion. He thought some information as to the
mechanical construction of the still, the area per gallon

of oil, or other information, could be given to show the
members exactly the details of working.

Mr. W. O. Humphreys (Beighton) asked if the light
oil depreciated in value when there was so large a
proportion of water in the heavy oil.

Mr. Nicklin said it did not. The plant in question
only depreciated in light oil to the extent that, in dis-
tilling such a mixture in the still, one also made low-
grade benzol—instead of 65 per cent., it would be
perhaps 60 per cent.—and that, of course, meant that
a greater proportion of light oils was carried over.
However, in the rectification, these light oils were
recovered and returned to the creosote, so that the
actual composition of the creosote did not vary to any
great extent.

Mr. Smith referred to troubles in the coils leaking
when using excessive diameters in the superheater,
which, when opened out, showed considerable corrosion.

The President, in summing up the discussion, said
his own experience was perhaps fortunate, inasmuch
as he had neither to buy nor sell the crude benzol, and
could therefore make it of what quality he liked; and
he was quite certain that, where it was possible, that
was the best plan to adopt—to get the largest possible
quantity of crude stuff out, whatever its quality, and
afterwards work it up in one’s own plant. He was
convinced that if they produced it at from 55 to 60 per
cent, in normal working conditions, at 120 degs. in
the retort they got a much higher yield than if attempt-
ing to produce 65 per cent, at 120 degs. Experience
suggested that water could be kept out of oil at a
temperature of 110 top and 165 outlet, but he cer-
tainly would not suggest that the efficiency was reduced
by anything like what it was represented when water
did get in the oil. Under breakdown conditions, he
had occasionally got as much as 60 per cent, of water
in the wash oil, and whilst there had, of course, been
heavy losses, they were nothing at all like what had
been mentioned in the paper—although those losses
were not agreed to by the authors, who were simply
quoting them.

Mr. Haigh, in replying to the discussion, said he was
glad Mr. Taylor had referred to the size of the still,
because that had a very important bearing on the
matter under discussion. They were mostly working
with plants with the design of which they had nothing
to do, and it was their business simply to work them
to the best advantage. The particular plant with
which he was connected was very small, with a still
only 3 ft. square, and, of course, that fact affected the
problem in a very marked fashion. The amount of
pre-heating was very small indeed, and it was there-
fore a matter of what could be done outside the still.
There was much room for further enlightenment on
that point, and in the preparation of their paper they
had found a French writer advocating that the amount
of wash oil through a 4 ft. still should be 400 gals, per
hour, and on one of 6 ft. diameter 1,000 gals, per hour.
The height, said Mr. Haigh, in reply to a question, was
not given. It was very satisfactory to find that, in
some respects—especially with regard to toluol content
—their conclusions agreed so closely with the results
arrived at by Dr. Spielmann and Mr. Petrie, whose
paper had not been published when the present on©
was prepared. In respect to benzol, their figures were,
on the average, some 5 to 6 per cent, low as compared
with those of Dr. Spielmann and Mr. Petrie, but the
former were taken from actual rectification tests, while
the latter was from benzol before rectification, and
perhaps the washing had something to do with the
difference in that respect. A good deal had been said
about the graph of comparative values, but it should
be understood that the results shown referred only to
those at the particular plant in question. Members
would have to prepare charts according to their own
plant and working conditions, and he was sure they
would find it very useful and profitable to do so. He
believed also the results of the work described in the
paper would be found to be borne out pretty correctly
in actual practice. In regard to the temperature of
scrubbing oil and gas, he would not advocate anything
so high as the 30 degs. mentioned by Mr. Carr; it
would only be adding waste to waste to increase the
oil temperature; anything like a normtl temperature
of 15 to 20 degs. for the gas would be a better figure,
but every member would agree that it would be better
to keep the oil a little higher to save condensation of
water in the oil. The question of water in the oil was
a very important one, and he was glad to find
that the president did not agree with Mr. Diamond’s
figures, as in the paper they had also expressly dis-
sociated themselves from those figures. It was very
important indeed to keep water out of the oil as much
as possible. It interfered with the efficiency of the
plant, not perhaps so much in the scrubbing, but unless
the still and pre-heaters were powerful enough to take
the water out of the oil, they would probably be giving
up benzol to the gas again, and the loss would go on
multiplying, and therefore the thing to be aimed at
was certainly to work with dry oil and use every means
possible to keep th© oil dry. Mr. Green had said that
the creosote in the benzol did not depend on the coal
used, but on the way the plant was worked. Person-
ally, he agreed that the creosote did depend almost
entirely on the working of the plant, and not on the
scrubbing at all. The figure of 14 per cent, of creosote
(to which Mr. Nicklin alluded) was taken from the
actual rectification tests, and did not include naph-
thalene. With regard to Mr. Thorpe’s remarks about
the amount of oil passing through the scrubbers, the
proper method, in their opinion, was to circulate as
much oil as possible in the last scrubber, and abso-
lutely debenzolise the oil passing through the still, in
order to get the best results. That was, of course,
equivalent to washing the gas to get the least vestiges
of ammonia out.

Mr. Lamb also replied to some of the points raised in
the discussion. Mr. Haigh and himself agreed as to
the varying proportions of constituents obtained in
summer working, but did not think the proportions
varied sufficiently to make any huge difference to the

retort test. Of course, the chart related only to their
own plant, and they made no attempt to adapt it to
foreign benzols. They endeavoured to scrub to the
utmost, both summer and winter, and, being favour-
ably situated with regard to water, they managed to
do so fairly well. With regard to the details of the
tests for saturation, he took a half litre of oil, usually
up to 260 degs. of residual distillate, took it up to
130 in the small flask, and found, on bulking all the
distillates, that they came very nearly to 65 per cent,
benzol, but it would not materially affect the satura-
tion. The expression 2 per cent, saturation benzol
meant practically 2 per cent. 65’s benzol in the oil,
and that was very low; but the special reason was the
smallness of their still. In reply to a remark by the
President that, if the still was small, surely it was
necessary to get the best saturation possible, Mr. Lamb
said they made some tests on the question of saturation,
thinking probably by increasing the saturation of
benzol in the oil they would throw less work on the
still. They did so, and increased it up to nearly 4 per
cent., and found that, although the relative stripping
on the still was more efficient than at the 2 per cent.,
they were sending the oil back to the plant with prac-
tically 1 pei' cent, of benzol. That was very poor
indeed, and they went back to the 2 per cent, satura-
tion, and still seemed capable of removing practically
all the benzol from the 2 per cent, oil, whereas if the
saturation was increased, it would not debenzolise.

Mr. Nicklin moved a vote of thanks to Messrs.
Haigh and Lamb for the abundant material for
thought furnished in their excellent paper. If work
was carried on at each individual plant on the lines
they suggested, the general knowledge of benzol would
be greatly increased and improved.

Mr. Smith, in seconding, said they were told by
responsible Government officials that the aromatics
were essential products of coke oven plant, and there-
fore it was their duty to get the largest possible yield.
To secure that, systematisation was necessary, and the
first step towards that was standardisation of works
tests. Very valuable work had been carried out by
works’ chemists, but the Government was so bound up
with red tape that the advantages of these investiga-
tions were largely lost. Failing Government action in
the matter, he thought it was the duty of that associa-
tion to devise some standardisation of tests.

The President, in supporting the proposed vote of
thanks, said Mr. Haigh had been a stalwart in the
association since its formation, and he had that day
increased the association’s obligations to him, whilst
the members also welcomed Mr. Lamb’s first contribu-
tion to their deliberations, and hoped it would be but
the start of further help of an equally valuable
character.

The vote of thanks was warmly accorded, and, in
reply, Mr. Haigh said the paper was written largely
with the hope of provoking discussion, and he was very
glad it had succeeded in that purpose. He was sure
that the views advanced in the course of the discussion
would be found to be of great value to the industry as
a whole. Mr. Lamb had carried out all the experi-
mental work in connection with the preparation of the
paper, and rendered invaluable assistance.

DIRECTIONS AS TO THE SALE OF COAL.

As we go to press we have received from the Con-
troller of Coal Mines a copy of the Revised Directions
as to the Sale of Coal, which will be dealt with fully in
our next issue.

COASTWISE COAL FREIGHTS.

The statement has been made in the daily Press that the
Shipping Controller has approved schedules of maximum
freights for coal, ore, and limestone carried coastwise ;
that this schedule, the particulars of which may be
obtained on application to the Ministry of Shipping,
will come into operation on February 1; that all
charters and freight contracts entered into on and
after that date must conform to the new scheme, and
that it is intended shortly to extend the scheme to other
commodities.

We have been in communication with the Shipping
Controller on the matter, but are informed that no
details are available for publication.

The Committee on Production have awarded to the men
employed in the malleable iron trades an advance of 5s.
per week to workers over 18 years of age, and 2s. 6d. to
those under 18, the increase to be a war advance, and
payable as from the first full pay in December last.

New Convalescent Home for Miners.—At a concert given
in the Creswell Colliery Institute on Saturday, on behalf
of the Derbyshire Miners’ Convalescent Home, Skegness,
Mr. Barnet Kenyon, M.P., said the present home consisted
of four boarding houses, and it was the intention of the
committee, provided they were backed by the men, to build
one worthy of the Derbyshire miners. Roughly, they esti-
mated it would cost from £9,000 to £12,000. Towards this
they had raised about £2,000 in subscriptions. Sir Chas.
Seely and Brig.-Gen. Seely, in regard to a site on the east
coast, had agreed to sell them the site of four acres at the
price put upon it by the National Valuer, and to return
half the cost.

Industrial Councils.—A conference of representatives of
employers in the metal, engineering, and connected trades
of the Birmingham district was held in the council room
of the University on Monday, with the object of consider-
ing the Whitley Report. Representatives attended from
six important federations and associations of employers.
The tone of the discussion was generally in favour of the
objects of the report, while critical of some of the methods
proposed. Several of the representatives were inclined to
emphasise the unity of interests among all the trades of
such a district as that of which Birmingham is the centre,
and to urge that this fact was not sufficiently recognised
in the report.