Figure 1.
Fluorine Gas Compressor
MECHANICAL FLUORINE COMPRESSION S. G . Osborne and 31. 31. Brandegee HOOKER ELECTROCHEVIICLL C O \ l P L \ l - , YILGAR4 F k L L S ,
I
\. Y.
S C O S S E C T I O S n-ith .\ 31 ECHhNICAL pump for the compressiou of fluoriuc ion ~ v x ,reached that. xt as deyeloped, based on two or more pulsating diaphragms in one locality, fluorine should a n installation of fluorine h!-draulically connected b?- liquids relatively inert to he stored i i i large tanks holdcclls procesa rcquirclmenti callcd for the intermittent u ~ v fluorine, and operated by a commercial reciprocatiup ing 200poundseach at a maximum p r e w r e of 30 pounds pump through the medium of a petroleum oil. Two s u c h of relatively large amounts of pumps were installed and have been operated successfull!. per $quare inrh; at this presgas during short periods oi for over a year and a half. sure it .qeemed possihle that time, followed hy periods me c h a ni c SI c o m p re s 5 i o TI of little or no consumption. I n addition, small amounts might be fcasihle without exof gas were required a t a nuniber of It-idely separated point.?. tensire and long-dran-n-out development and research. h small number of fluorine cells i7ei-e installed xvith storage The prohlem in mechanical compression is that, although many tanks to take up the variation in the use of the gas rather metals Trill withstand fluorine attack a t low temperatures and than fluctuating the amperage on the larger number which would .wine at fairly high temperatures, their resistance is based on a protective layer of fluoride d i i c l i prevents further reaction. Ohhave been required to handle the niaiinium load. I t was deviously if the protective layer is removed by mechanical friction, sirable to provide a less expensive method of filling storage tank? :xi b y the piston of a reciprocating pump, a ne^ layer will form with fluorine gas under moderate pressure than condensation n i t h : ~ n dagain be removed and the metal will bc continuously conliquid nitrogen followed by re-evaporation, and the diaphragm stimcd. There is also the serious problem 13f lubrication, for pump described here was devised. fluorine \Till react v i t h fine carbon or graphite and n i t h hytlroFew actual experimental data are given because the first pump i,:ulmns and lubricating oils, escept, to some extent, those in Ivhich was put into immediate pilot plant operation, and only shut d o w i for inspection and the mechanical modification of the valves a3 ail hydrogen has beon replaced with fluorini,: even the latter react under certain conditions of high pressurch and teinperaturc. found desirahle. The large pumps n-ere installed a t the site after These considerations suggested a diaphragm pump because operation of the plant had been transferred to others, and operatthe metal pumping surface is only slightly deflected and n o t ing data are not available. rubbed or subjected t o friction. and no luhricant is rcquireil. Fluorine cells are quite flexible as far as load changes are concerned, but the control of temperature and particularly the conSuch punips viere available, operated hydraulicslly hy oil through trol of hydrogen fluoride concentration in the electrolyte arc the medium of a motor-driven reciprocating pump. It \va> greatly complicated under such conditions. t,!ivious that, if the diaphragm should break, the oil \vould take Sothing was found in the literature on the mechanical conifire through contact with fluorine and probably hurn up the c'spression of fluorine, but it is recorded t h a t Noissan and Den-ar pi.niiue pumping mechanism. T o avoid thi.. a .econil @miping liquefied it in 1897 b y means of liquid oxygen. It is of interest head ivas provided of the Same size a$ thc first, and connectclrl to that a t this lo\\- temperature (-187" C.) glass, silicon, fine carbon. i: by a length of pipe which passed through a fire ~ r u l land colisulfur, and powdered iron did not react n i t h fluorine. rained a highly fluorinated hydrocarbon of low vapor pressure. Fluorine can be rather easily liquefied a t low temperatures and Origindip, when higher pressures than 30 pound> p u r square' iiic.li then be transferred into containers under pressure by re-eraporawere under discusjion, it n-as felt t h a t even tlii? iiiiglit not I ) e tion, but large quantities of liquid nitrogen are consumed and the .Gufficient protection; therefore, it as consiclered that a tirirti lahor cost is high. This procesq has been used on a consitlerahle pumping head might be ncceawry to he hydraulicnlly connoctivl scalv, particularly bj- the I l u Pont Company, for packaging \:.itli the second, h y liquid aiitiniony pent:LHuoi,itlo. There woultl fluorine into small cy1inder.s under several hundred pounds prestiii'n be the scquc'nce fluorinc~aiitiiiii,11?-pt~ntnfluriritle1 niatle sure; hut so far it, has been considered safe to liquefy only a feni)y reaction n i t h nuoriIie)----tfluoriIiatetlliytli~oc~lrhon (iii:ulo I)? pounds at a time and the process is slon-. reaction n-ith antimony pentafluoridei+oil. n-it11 .i.pur:ition I)),
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INDUSTRIAL AND ENGINEERING CHEMISTRY
VOl. 39, No. 3
metallic diaphragms. A fluorinated hydrocarbon \vas t o Le chosen n-hich n-ould n o t react with the oil in the reciprocating pump. Except for this oil each nieniber oi the sequixnce is produced by reaction nit11 the one directly a1ic:itl of i t and is, therefore, inert to both the one ahead of and the one I~eliindit.
Cu. F t . , Hr.
a t 60'
E'.j, 30 I n .
IIg
Delivery P r e l s u r e , 1,b. ''4,
In
10
10 4
30 50
Figure 2. Hydraulically Operated Diaphragm Pump
This is obviously a coinplicatcd and unsatisfactory srrangcnient, and diaphragm punips are of lo\\ capacity. Fortunately it was decided t o compress to only 30 pounds pctr square inch and t o use larger containers. *it this pressure it was believed that the fluorine could be pumped directly 1)y the second diaphragm without much risk.
PREJESTED before
tile S'yniposirrin o n I'luorinc Chemistry as i ) a l x r 3 8 , Dirision of I n r i n ~ t r i a la n d E n g i n e e r i n g C h e m i s t r y . 110th l l p e t i n g of t h e . i M E R I C . 4 S C H E \ l I C . & L S O C I S T Y , ChiCaL?O. 111.
DESCRIPTION OF PUZIP
.lvailable commercial diaphragm pumps w r e dwigncd for handling liquids, and it was redesign the valve head mid v a l v i ~conipletely i n or e the various clearances t o a minimum for gas conipi csperinicntal punip \vas indalled at Siagara Falls, having 13-inch-tliameter diaphragms, made of 20-gnge AIonel, installed in solid 11onel heads about 3Va inches t h i c k (Figure 1). The motion of the diaphragms \vas inch: since tmth sides n-ere a t substantially the same prescure, nicch:mic*alrupturv was not expected t o take place, although eventual fnilurcl iiy fatigue due t o bending \vas to be cispected. I'ractical esperiencc i n pumping liquids indicated a long cliaphragni lifc, but tlic effect of fluorine under temperature and pressure condition> K ~ not F knoi This pump coii&ted of four ntial parts: a reciprocating iiiec han i siii ivh ic I i pulsitt cd the diaphragm by oil pressure, :i (liaphragni h e : d directly adjawnt to thu reciprocating niechani.;m, n rcniotc gns pumping head wparated by a fire wall and c o n n e c t d hydrdic:dly n-ith thc, first diaphragm by a %foot l,.ngtli of 2-inch niclwl pipe containing the fluorinated hydror u b o n , iiiid :i x-:ilt-
