SCIENCE AND INDUSTRY. 
ee 
in the development of an oil-shale industry in the United States, a 
new art here, would be an attempt to apply the apparatus and practices 
now used in the country where oil-shale operators have reached their 
highest development. If Scotch methods are not found satisfactory 
in this country, it may be possible to modify them, and even if modifica- 
tions are unsuccessful, the knowledge of Scotch shale operators, based 
on over sixty years of practical experience, cannot reasonably be disre- 
garded but logically should serve as points of reference. 
In Scotland the shale brought from the mine is crushed by toothed 
rolls into pieces of average size of an ordinary brick; as a rule every- 
thing going through the rolls goes to the retort. 
Scorcy Rerorts. 
From the breakers the shale is carried in cars up an incline to the 
top of the retorts, where it is dumped into the retort hoppers by hand. 
The most commonly used Scotch retorts are vertical and tapered, con- 
sisting of thé following parts:—At the top there is a hopper, which 
holds several hours’ supply of shale. Below the hopper is a cast-iron 
upper part which is about 12 feet in length and which has a vapour 
outlet near the top. Under the cast-iron part, and joined to it with a 
fireclay joint, is the lower masonry part, which is about 18 feet high 
and made of a single tier of very special-shaped firebrick. At the 
bottom of this part is the discharge mechanism and below that the spent- 
shale hopper, which serves one or two retorts and in which the spent 
shale accumulates. The cast-iron part is made circular or elliptical in 
cross-section, and the masonry part square or circular. Those of 
circular cross-section have an internal diameter of about 2 feet at the 
top and 3 feet at the bottom. The taper is constant. 
Each retort, with its supply hopper, holds about 9 tons of shale 
and the feed is by gravity. Four retorts, as described, are set in a 
common furnace and are heated by the combustion of the fixed gases 
resulting from the distillation of the shale, supplemented by coal 
producer gas when necessary. Four retorts are a unit, and sixteen 
such units constitute a bench, two retorts wide and thirty-two retorts 
long. The present retort working on shale now being mined in Scot- 
land has a capacity of about 4% short tons per day. ‘Tests indicate that 
the retort capacity is a function of oil production rather than shale 
throughput. Apparently a Scotch retort will produce approximately 
100 gallons of oil a day, whether it is working on a 10-gallon shale or 
100-gallon shale. In the former case approximately 10 tons can be 
put through; in the latter but one. 
In the upper or cast-iron part of the retort most of the oil distills 
and the maximum temperature in this part does not exceed 900 degs. F. 
The lower or masonry part serves mainly as an ammonia and gas 
producer. About 105 gallons of water, as exhaust steam, for each 
25 gallons of oil produced, is admitted into the spent-shale hopper and 
passes up through the shale in the retort. The steam serves to absorb 
the heat from the spent shale, to produce water gas from the fixed 
carbon remaining in the spent shale, to distribute evenly the heat in the 
retort, to produce ammonia from the nitrogen of the shale, and’to carry 
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