A Burnett apparatus for the accurate determination of gas compressibility factors and second virial coefficients, and an evaluation of its capability based on some results for argon and carbon dioxide

Abstract

A Burn e tt a ppa ratu s has bee n d e ve lu pe d for th e de te rmin a ti u n uf th e cumpress ibilit y fac tu r uf gases, in cludin g c orrus ive ha loge ni c ga ses, to a n acc urac y of 0.1 pe rce nt to 0. 01 pe rce nt at te mpe ra tures fro m 0 to 225 C a nd for press ures up to 250 ba rs. T he a ppa l'a tu s has bee n used thro ughout thi s te mp e ra ture a nd press ure ra nge a nd a t te m pe ratures within 15 C of th e c riti ca l te m pe ra ture of th e s a mpl e gas. T he a ppa ra tu s fea lures a ru gged ye t hi ghl y se ns iti ve a nd re prod ucibl e null-Iype press ure tra nsdu ce r to isula te th e s a mple gas with o ut inlrud uc in g a press ure un ce rt a int y gre a te r th a n th e prec ision of th e pre ss ure m eas ure me nt s, whi c h is be tt e r th a n 1 pa rt in 50 ,000. Th e press ure mea s ure me nt s a re acc ura te to at lea s t I pa rt in 20 ,000. Th e redu cti o n of th e da ta is di sc ussed ex tens ive ly. Th e capa bilit y of th e a pp a ra tu s ha s bee n e valu a ted in te rm s of th e c ompre ss ibilit y fa c tor re prese nted by a finit e press ure or de n sit y vi rial e xpans ion a nd d e rived from a rgo n d a ta a t 25 C a nd press ures up to 250 ba rs and in te r ms of th e secund vi ri a l cue ffi cie nt of ca rbo n di ox id e based on data at 50 C a nd press ures be low 35 ba rs. Th e va lu e ubt ain ed fur thi s s ecu nd viri a l c~e fli c i e nl. -102 .2 O .2 c m"/ mol. c om pa res fa vora bl y with th e va lu e uf -102.5 c m"/ mol ob ta in ed fro m a rece nt correla ti on a nd is in s ubsta nti a l di sagree me nt with th e va lu e of -100.7 O.4 c m "/ mol d e te rmin e d by Dad so n a nd cu wo rk e rs fro m th e Burn e ll me th od a nd th e pie zo me te r me th od .