513.    CHEMICAL ENGINEERING.  Oxygen, Past, Present, and Prospects.  Vol. 54, No. 1, 1947, pp. 123-131.

                   The search for cheap O₂ (that containing from 88-98% O₂) has received considerable impetus recently, and it appears likely that such low-purity O₂ can be produced for a small fraction (about 4% or less) of the present cost of high-purity gas, provided it is made in large units, operated at substantially constant rate, and installed at the point of use.  Estimates of costs range from $0.048 for 1,000 cu. ft. of 95% O₂ in a plant of 48,000,000 cu. ft. per day capacity to an average of $0.12 including all the factors in power cost.  In Germany the Linde-Fränkl, low-cost low-purity O₂ process was able to produce 98% O₂ in a large plant for 1.53 pf. per m.³ ($0.10 per 1,000 cu. ft.).  Of the total costs, power cost amounted to 58.8%, depreciation 31.4%, wages 4.9%, and water, lubricating oil, and chemicals 4.9%.  Much research has been done in the United States and developments by several companies are commented upon, and a number of applications for cheap O₂ are presented.  The principal uses include hydrocarbon-synthesis, steel-industry, and gas-industry applications, the technical feasability and the economic justification of which still require further proof.