This sentence explains from what background is valued the low temperature separation method which is a means of producing the hydrogen for chemical industry, and introduces the plant recently established for recovering the hydrogen gas from the ammonia plant as the above mentioned effective utilizing method.
Then it describes in what procedures the Joule Thomson effect of mixed gases, of which few measured data are available, has been estimated in case of getting the various items composing the heat balance of the plant, and is obtained the vapor-liquid equilibria during the separation process from the operating data.