slowly and oil vapours made are at once swept away to a cooler zone 
and out of the retort by the excess steam and gas, thus effectively 
protecting the oil from excessive decomposition. 
By-propucr AMMONTA. 
The question of producing ammonia from oil shale is one that has 
been discussed at considerable length by those interested in oil shale 
in this country. The average American oil shale compares favorably 
with Scotch shale in nitrogen content, and it is to be expected that the 
nitrogen in both shales can be recovered with equal ease. The general 
tendency among Ainerican oil-shale processes seems to disregard 
ammonia recovery except the small amounts incidentally produced in 
ordinary dry destructive distillation. It is felt by many that the con-. 
version of the nitrogen in a rich oil-yielding shale into ammonia is not 
a desirable thing, as such conversion would reduce the retort capacity 
for oil. While this is probably the case, there is nevertheless a fair 
probability that the increased returns made by producing ammonia 
would more than counterbalance the decreased oil-producing capacity 
of the retort, assuming a satisfactory market for the ammonia exists. 
This may particularly apply if it is found that steaming the retorts is 
necessary to produce the best grade of oil. To produce maximum 
economic yields of ammonia from oil shale, Scotch operators find a 
maximum temperature of about 1,500 degrees I’. and an excess of steam 
necessary. While 900 to 1,000 degrees seems to be the highest tempera- 
ture necessary to produce oil from oil shale, the increased heat needed 
to produce the ammonia is nearly if not completely supplied by the 
combustion of the gas produced by the action of steam on the carbon 
of the shale in the ammonia-production part of the retort. 
The use of steam in retorting is said by the Scotch operators to 
increase the yield of ammonia over two and one-half times the amount 
recovered by straight dry destructive distillation. In discussing the 
ammonia-recovery problem, it is necessary to point out the possibility 
of recovering part or all the nitrogen of the shales in some form other 
than ammonia, such as pyridine compounds and the like, and also the 
conducting of the oil-recovery and nitrogen-recovery operations im. 
separate and more or less independent apparatus. Both of these possi- 
bilities require thorough study, and whatever is done in the way of 
recovering nitrogen must take into account the main purpose of oil- 
shale treatment—that is, oil production. 
Quaniry anp Quantiry or YIELD. 
The writer has examined oils from Scotch plants and oils produced 
by different processes from various American shales, and has found that 
the quality of the Scotch oil is in every way much better than any oil 
he has thus far seen from American shales. Whether this is mostly 
due to the nature of the processes or to the shales themselves he is not 
definitely prepared to say, although it is known. that the conditions 
under which oil is produced from shale have a very decided influence 
on the quality and quantity of oil yield. However, it has also been 
determined that different shales, retorted under identical conditions, 
do yield somewhat different oils. Both factors undoubtedly influence 
the quality of the oils yielded to a considerable extent. 
752 
