SCIENCE AND INDUSTRY. 
Frow Surer or Propvots ann Pranr Lay-our. 
Practically all refinery distillations are conducted with a large 
quantity of steam, which is admitted into the bottoms of the stills. 
The crude oil is run to coke, as are also some of the redistilled oils. 
The yield of refined products in Scotland is somewhat as follows :— 
Per cent. 
Naphtha (including scrubber naphtha) 54 deg. end point .. 9.9 
Burning oils (kerosene and the like) ay P24 
Gas and fuel oils .. ga AS aks 2% eee 2.4.64. 
Lubricating oils =e it re os; cee OFT) 
Wax ae e 3. me +5 cls eo s0} 
Still coke ; a” on on YAW 
Loss 22.8 
100.0 
A general idea of the complexity of shale-oil refining in Scotland 
can be gained by referring to Fig. 1, a generalized flow sheet of refinery 
operations at a typical Scotch shale works. This figure and Fig. 3 are 
presented through the courtesy of Scottish Oils Ltd. The writer wishes 
to express his appreciation particularly to H. R. J. Conacher of this 
organization for the use of these figures. 
Serubber naphtha, which is the gasoline or naphtha recovered from 
the retort gases by washing them with oil and subsequently distilling 
the latter, amounts roughly to 2.4 gallons per ton of shale. 
Ammonia water from condensers and scrubbers is run to ordinary 
continuous ammonia stills. Ammonia gases pass off and are dissolved 
in dilute sulphurie acid, much of which is recovered from the acid tars. 
The sulphate solution is concentrated by a continuous system and is 
finally purified and sold as crystalline ammonium sulphate. 
Fig. 2 is a plan of a typical modern Scotch oil-shale works, including 
retorting plant, oil refinery and ammonium sulphate plant, with acces- 
sories. It serves to indicate the outlay and equipment necessary in 
the production and marketing of refined oil-shale prodwets, and gives 
an idea of the scale under which Scotch operations are carried on. 
Such a plant represents the investment of several millions of dollars. 
The principal objection in the minds of American shale operators 
to the Scotch retort is its low throughput and its use of steam. Scotch 
operators find that it is necessary to heat their shale slowly and to use 
plenty of steam if a satisfactory oil is to be produced, and the past 
tendency in Scotch practice has been to lengthen the time of treatment 
and use more and more steam. As a matter of fact, the amount of 
steam used is largely determined by the amount of oil a shale will 
yield. Rapid production of oil from Scotch shale has meant that an 
oil of poor quality resulted, though not enough work has been done on 
American shales to determine if they will behave the same way. 
The use of steam in retorting apparently does so much more than 
merely produce ammonia that its use cannot be abandoned without 
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