UNITED STATES PATENT OFFICE.

ERN EST. A. L E SU EUR, OF OTT AWA, CANADA. PROCESS OF EXTRACTING LIQUID METHANE FROM NATURAL , SPECIFICATION forming part of Letters Patent No. 668,197, dated February 19, 1901. Application filed July 18, 1900, Serial No. 24,043, (No specimens.) To att, whom, it may concern: may in this case conveniently be obtained Be it known that I, ERNEST ARTHUR LE from the of the inferior gaseous SUEUR, a citizen of the Dominion of Canada, rejected from the natural gas in the residing at Ottawa, in the county of Carleton, process of separating the methane, and the Province of Ontario, Canada, have invented whole of the original raw material thereby be a certain new and useful Improvement in economically utilized. Processes of Extracting Liquid Methane from My process is as follows: I take the natural Natural Gas, of which the following is a speci gas to be treated and lower its fication. to a suitable point by any convenient and Well Of all commercial fuels natural gas has by known means. Certain impurities, such as far the highest value, having per thousand hydrogen sulfid and dioxid, (if con feet one hundred and fifty per cent. the ther tained as above,) separate out in the solid mal value of good coal-gas, over three hun form, and I carry the refrigeration to a point dred per cent. that of water-gas, and over six at which the methane liquefies in whole or in hundred per cent. that of good producer-gas. part. In liquefying it dissolves more or less Its great value is on account of its high per completely, depending on the composition centage of methane, the heating power of and procedure, as above, certain other con which alone is considerably greater even than stituents of the natural gas-such as hydro that of natural gas. My invention provides gen, , and caibon monoxid or such a means whereby the latter material may be of these as exist in the particular gas under extracted in a comparatively pure form and treatment. I then subject the liquid to a cer one, moreover, which adapts the methane for tain amount of fractional , where convenient transportation. by is expelled from solution a gaseous mix I have discovered that natural gas when ture far richer in the last-named impurities 5 highly refrigerated liquefies completely at a than is the liquid itself. This gaseous mix temperature far above that at which, for in ture is useful as a fuel, although much less stance, the nitrogen, hydrogen, and carbon so than is methane. Impurities appearing, monoxid contained in it would liquefy sepa as above, in the liquid product in the solid rately. This statement has to be modified to form are filtered or settled out, and the final this extent, that if more than a trace of hydro product consists of almost pure liquid meth gen sulfid or carbon dioxidis contained in the ane. For purposes of storage and transport particular gas treated the said substances ation it will be placed in tanks covered with separate out in the solid form. any suitable non-conducting material, and If instead of carrying the process to the said tanks may either be left open, so that point of complete liquefaction I stop slightly the liquid contents may, by boiling at atmos short of this point, the resulting liquid dis pheric pressure, keep the temperature down solves only partially such constituents as hy to the boiling-point at the said pressure or drogen, nitrogen, and carbon monoxid, and may be made strong enough so that they I may thus prepare a comparatively pure liq may be closed and a pressure be generated uid methane directly. The highly-discrepant in them (regulated by a safety-valve) suffi compositions of different varieties of natural ciently high to enable storage to be effected gas cause its behavior at any given pressure at a much higher temperature than would and temperature to vary considerably. otherwise be possible. If I resort to complete liquefaction of the The portion of my process involving frac natural gas, I eliminate the nitrogen, &c., later tional distillation may conveniently be effect by fractional distillation. The method I prefer, ed (in cases where the liquid is to be stored (depending, however, on the particular com or transported before use) during said stor position of the gas under treatment,) instead age or transportation simply as a result of the 3 of resorting to initial complete liquefaction, access to the containing vessels of heat from 50 is to combine “fractional ’ with outside sources, and the dual result thereby fractional distillation later on. The power accomplished of purifying the liquid and of required for refrigeration and other purposes furnishing the chilling effect necessary to

L.a 668, 197 maintain the methane proper in the liquid occurs and then subjecting the resulting liq form. uid to fractional distillation, substantially as In transporting the liquid the gas which described. boils off from it during said transportation 3. The process of preparing liquid methane may most conveniently and economically be in a state of comparative purity which con used in the combustion-chamber of the en sists in chilling natural gas until liquefaction gine which applies propulsion to the vehicles occurs in whole or in part, subjecting the liq conveying said liquid. quid to fractional distillation and separating It will be obvious that the fractional dis certain impurities from said liquid in a frozen O tillation referred to above may be effected condition, substantially as described. by lowering the pressure on the liquid, and 4. The process of preparing liquid methane 35 thereby causing boiling. For instance, the in a state of comparative purity which con liquid may be produced to begin with under sists in chilling natural gas until partial high pressure and fractional distillation in liquefaction occurs, whereby is precipitated duced thereafter by relief of pressure. a liquid richer in methane than is the origi 4.d What I claim is- - - nal gas, and then in subjecting the said liq 1. The process of preparing liquid methane uid to fractional distillation, whereby the liq in a state of comparative purity which con uid is further freed from impurities, substan sists in chilling natural gas until partial tially as described. liquefaction occurs, whereby is precipitated In testimony whereof I affix my signature a liquid richer in methane than is natural in presence of two witnesses. 45 gas, substantially as described. ERNEST A LE SUEUR. 2. The process of preparing liquid methane Witnesses: in a state of comparative purity which con LEPINE HALL RICE, 25 sists in chilling natural gas until liquefaction MAUDE B. BAGLEY.