High surface area aluminum structured packings are possible components in cryogenic distillation columns used for air separation. Recently published literature has reported on the occurrence of strong energy releases involving aluminum structured packing which was subjected to flammability tests in the presence of liquid oxygen using strong thermite and magnesium promoters, under conditions which may not be typical of operating conditions in a cryogenic distillation column.
An experimental program was conducted to determine the compatibility of aluminum packing under test conditions which more closely simulated actual column operating conditions. The effects of various thermite, magnesium, hydrocarbon and metal promoters were evaluated in LOX/GOX environments with a nominal oxygen purity of 99.9% at pressures up to 0.17 MPa.
A major finding was that aluminum packing which was “irrigated” with LOX but not immersed in LOX did not experience severe energy releases in flammability tests up to a maximum pressure of 0.17 MPa at a nominal oxygen purity of 99.9 %. This simulated column operating conditions. Elimination of packing “irrigation” and immersion of the aluminum packing at one end in LOX resulted in a severe energy release in one test conducted at 0.16 MPa. The latter result verified recent literature reports but was not considered representative of packing operating conditions.
Of particular interest in this paper are details and schematics of a pressurized test vessel which was designed for the program. This test apparatus is capable of providing various combinations of packing immersion and irrigation, thereby simulating actual operating conditions.