Ignition of Aluminum by Impact in LOX - Influence of Contaminants

摘要

Impact tests in LOX according to ASTM D 2512 were conducted on thin aluminum films (7 to 20 urn) together with glass fibers films used for the super insulation of vacuum insulated cryogenic vessels. Influence of the film thickness, type of material and number of layers were investigated. Practical information is given concerning the requirements for such insulation. Impact tests in LOX according to ASTM D 2512 were also conducted on thick aluminum foils (0.2 mm) used for heat exchangers of air separation units (ASU). Test samples were usually three layers of corrugated foil contaminated by various hydrocarbons but mainly by hexadecane. The standard striker pin as per ASTM D 5212 and also a modified striker pin were used. The influence of HC contaminants (type and quantity) on the Al foils, but also of impurities in the LOX (N_2O, Ar, N_2),was investigated. The results of these tests can be used to understand the risk of ignition of some aluminum exchangers or structures used in ASU.