Section III, 1919 [57J Trans. R.S.C. 



Composition of the Vapour and Liquid phases of the System 

 Methane- Nitrogen^ 



By Captain H. A. McTaggart and Mr. E. Edwards, M.A., B.Sc. 



Presented by Professor J. C. McLennan, F.R.S. 



(Read May Meeting, 1919.) 



Synopsis 



1. Introduction. 2. Measurement of Temperature. 3. Gases 

 Used. 4. Method of Analysis. 5. General Description of Apparatus. 

 6. The Cryostat. 7. Manipulation. 8. Results. 9.. Summary. 



Introduction 



The problem — now a commercial one — of the separation of helium 

 from natural gases bears a resemblance to the recovery of argon from 

 the atmosphere. Helium occurs in the richest natural gas wells in 

 about the same proportion — 0-9% — as argon does in the atmosphere, 

 and its separation at present is being efïected in a similar way, viz.: 

 by the method of liquefaction and rectification. 



There is this difference, however, that while argon is recovered as 

 a by-product in a very important industry, viz.: the manufacture of 

 oxygen and nitrogen from the air, the separation of helium from 

 natural gases is being carried out for its own sake. This adds con- 

 siderably to the cost of production, a cost which might be reduced and 

 probably will be when the liquefaction method as applied to natural 

 gases is made more efficient. 



A detailed examination of the conditions under which these 

 gases liquefy ought to give useful information in this direction. 



Wells yielding helium to any extent are found to contain as the 

 chief constituents, methane and nitrogen. For example, a well in 

 Texas, U.S.A., yields a gas of the following composition: 



N, 34-0%; CH4, 52-0%; Hydrocarbons, 12-3%; CO2, 0-8%; 

 O2, 0-8%; He., 0-9%. 



Another well in Alberta, Canada, has: 



N, 8-7%; CH4, 91-1%; CO2, 0-1%; O2, 0-1%; He., 0-36%. 



For this reason the system CH4— N was chosen for preliminary 

 study, and the boiling points at atmospheric pressure of various 



^ Communicated by Professor J. C. McLennan, F.R.S., by permission of the 

 Admiralty. 



Sec. III. Sig. 5 



