Cercetări privind creşterea performanţelor la separarea fracţiei de argon din aer

Abstract

This PhD thesis addresses an issue with a significant impact in cryogenic air distillation technique, argon being one of the rare gases whose request for the technology sector and research has increased significantly, especially after 1970. This request was manifested mainly in two sectors with major impact on current technology namely the production of high quality stainless steel, and the production of high purity crystalline silicon. The very high inertia degree of the argon is essential for both technologies. The main source for obtaining argon is atmospheric air, by having 0.93 volume percent concentration. Argon production is associated to high purity oxygen production in cryogenic air separation. Cryogenic air separation plants are responsible for 0.1% of world electricity consumption. This point out the importance of energy management awarded the cryogenic air separation plant. In some situations, the reverse engineering method is used in cryogenic air separation designing, as input being the availability of electricity and no plant productivity, in terms of purity of the products of air separation. A large part of the effort to reduce energy consumption is focused on process integration and thermal insulation of the facility (for reducing the cold production), as well as for working pressure decrease in the distillation columns and heat exchangers (to decrease the compression load of the the compressors). Yet, in addition to exergy optimization is another approach focused on better control of the process (in order to energy optimization). Both approach (thermodinamic and control) are interdependent, due to the nature of the ternary mixture separation process (nitrogen + oxygen + argon).