156.    BATCHELDER, H. R., TENNEY, R. F., SKINNER, L. C., DRESSLER, R. G., AND HIRST, L. L.  Role of Oxygen in Production of Synthetic Liquid Fuels From Coal.  Trans. Am. Soc. Mech. Eng., Process Ind. Div. Conf., Paper 50-PRI-7, 1950.

                   Use of O₂ in place of air or of external heating in the gasification of coal for the production of H₂ for coal hydrogenation or of CO-H₂ mixtures for Fischer-Tropsch synthesis may have 1 or more of the following advantages:  (1) Fuel economy; (2) increased capacity of equipment; (3) wider range of possible fuels; (4) greater adaptability to pressure operation; and (5) a higher range of attainable temperature.  As to the relation of O₂ cost to that of synthetic fuel, it is well established that for the Fischer-Tropsch process about 690 lb. O₂ are needed to make 1 bbl. of synthetic liquid fuel.  This amount of O₂ at $5.00 per ton would amount to $1.72 per bbl. and at $3.00 to $1.03.  Each change of $1.00 per ton in the cost of O₂ will change the bbl. cost of synthetic fuel by about $0.35.  For comparison, similar calculations made on coal would show that a change of $1.00 per ton in price would result in a change of about $0.40 per bbl.  The O₂ requirement for coal hydrogenation is only a fraction of that for the Fischer-Tropsch process due to the fact that in the former process a relatively large part of the required H₂ is to be recovered from the tail gases by low-temperature separation or by reforming the product CH₄ with steam.  It is estimated that about 90 lb. O₂ will be required to make 1 bbl. of synthetic fuel by coal hydrogenation.  At $5.00 per ton the O₂ cost would be $0.22 per bbl. of oil and at $3.00 about $0.14.  Each change of $1.00 per ton in the cost of O₂ will change the bbl. cost of oil by about $0.04.