Cracked C4 Cut: Cracking-Still Gas Liquefied and Split in Four Columns at 200 psi (Eastman, Texas Co., US 2,014,724)

The gas from a cracking still is a mixture of light hydrocarbons. Compress it, chill it until it liquefies, and run it through four columns in turn: each column sends one group off its top, and the fourth gives the butanes and butylenes together, the C4 cut. Result: a liquefied butane-butylene cut. Eastman does not give its composition. Source: Eastman, US 2,014,724 (1935). Not given: the cut's make-up, how the impurities are removed, the refrigerant. The gas from Burton's still is used here as the same kind of cracking-still gas. Extremely flammable gases under pressure. Picture drawn by Youblob.