UNITED STATES PATENT OFFICE. FRED BEDFORD AND CHARLES ED. WILLIAMS, OF SLEAFORD, ENGLAND, ASSIGNORS To CEDFORD GAS PROCESS COMPANY LIMITED, of LoNDON, ENGLAND. CATALYTIC SYNTHESIS OF METHANE. 989,755. Specification of Letters Patent. Patented Apr. 18, 1911. No Drawing. Original application filed February 25, 1910, Serial No. 546,016. Divided and this applica tion fled December 19, 1910. serial No. 598,228, To all whom it may concern: cooling of the gases to a degree sufficient l3e it known that we, FRED BEDFOR) and only to liquefy them with a view to the sepa CHARLEs, EDWARD WILLIAMs, subjects of the ration of certain of the constituents. But IXing of Great Britain and Ireland, and none of these processes have been so far com 5 residents of Sleaford, in the county of Lin mercially successful. coln, England, have invented certain new The object of this invention is to provide a 60 and useful Improvements in and Connected process by which the sulfur impurities may with the Catalytic Synthesis of Methane, of be effectually removed and at the same time which the following is a specification. the cheapest of the commercial gases of the 0 This invention relates to an improved type of Mond gas and Duff gas and the like process for the catalytic synthesis of meth may becommercially treated for the produc 65 ane or a mixture of methane with other stion of methane, without there being any gases and is the complement of the invention need to modify their process of manufacture. set out in specification to our co-pending In carrying out this process the mixture 5 application Serial No. 546,016. of gases (which should be first freed from The value of ordinary coal gas is due to carbon dioxid) is cooled to the degree neces 70 the large percentage of methane contained sary in order to get the sulfur impurities therein, and attempts have been made to into a solid form having little or no vapor produce methane synthetically from carbon tension, the hydrogen passing off as a gas 20 oxids by the action of hydrogen in the pres and being collected while the carbon mo ence of finely divided nickel, the function noxid, nitrogen, and methane will be liquid 75 of the latter being simply catalytic. The or solid. On allowing this latter mixture to reactions which take place may be repre evaporate carbon monoxid and nitrogen dis sented by the equations:- till off first and are effectually separated from 25 the sulfur impurities. After this distilla CO--3H, -CH,--H.O tion process a certain quantity of the carbon 80 CO,-4H =CH-2H.O. monoxid obtained is mixed with the hydro This catalytic reaction proceeds Smoothly gen so that the hydrogen and carbon monoxid provided the reacting gases are pure, and are in the required proportions and this mix 30 provided also that hydrogen is present in ture is passed overnickel in the known man sufficient quantity as demanded by the above ner. There should always be an excess of 85 equations. If, however, the reacting gases hydrogen over the theoretical quantity in contain certain substances - hereinafter order to prevent local heating of the metal. termed impurities--such as sulfureted hy The amount of this excess depends on va 35. drogen, carbon disulfid, mercaptain, and sul rious circumstances, such as the speed at fur compounds in general, even if only which the gaseous mixture is passed over 90 very minute quantities, the nickel very soonin the metal, and if nitrogenis present this acts loses its activity. In order, therefore, to as a diluent and assists in preventing local preserve the activity of the nickel, it is essen heating, and a smaller excess of hydrogen 40 tial that the impurities invariably present in may be used than would otherwise be neces commercial gases be carefully removed be SaW. . 95 fore the latter are allowed to come in contact illustrate one mode of carrying out the with the catalytic nickel. Various processes. invention, suppose it be required to prepare have been proposed for the removal of the methane synthetically from a Mond gas of 45 impurities. Again all commercial gases ob the , following approximate composition: tained by gasifying coal and containing hydrogen 28 percent carbon monoxid 11. OO hydrogen and carbon monoxid are deficient per cent, carbon dioxid 16 per cent. Ineth in hydrogen, Warious methods have been ane 2 per cent., nitrogen 43 per cent. The proposed for the removal of the sulfur im carbon dioxid is first removed in any known 50 purities, and for obtaining carbon honoxid manner, for example, by absorption in a and hydrogen in the proper relative quanti solution of sodium carbonate, such removal 05 ties, either by varying the mode of manu being desirable to: E. the clogging of facture of the gases or by adding hydrogen. the apparatus by the carbon dioxid. The Some of these methods have depended on the residual mixture is passed through a cool

2. 989,755 ing apparatus adapted to cool it to a tem it is present or not during the catalytic re perature of about -190° C. A cooling ap action. paratus of the well-known type used in the fractionable abstraction method of obtain Having now described our invention what. 5 ing oxygen from the air may be employed we claim as new and desire to secure by for this purpose. After this cooling proc Letters Patent is:- - 40 ess the hydrogen passes off as a gas carry 1. A process for the catalytic synthesis of ing with it small quantities only of carbon hydrogenmethane fromand acarbon commercial monoxid gas comprisingcontaining monoxid and nitrogen but leaving behind cooling the commercial gas to such a de O it the bulk of these gases with the methane gree that the impurities separate out in the and all the sulfur impurities in the solid solid form possessing little or no vapor 45 gas.form Thethat hydrogenwere present may in be the collected commercial in a tension, separating the purified gas into its suitable tank or holder while the mixture constituents, mixing the carbon monoxid 15 which is left behind in the cooling apparatus thus obtained with hydrogen, and passing is evaporated so that the carbon monoxid the mixture into contact with a heated 50 and nitrogen distill off first, and these may catalytic substance for the purpose set forth. be separated by known means, for example, 2. A process for the catalytic synthesis of by Ei of the carbon monoxid by hydrogenmethane fromand acarbon commercial monoxid gas comprisingcontaining 20 means of cuprous chlorid solution from which carbon monoxid may be again ob cooling the commercial gas to such a degree 55 tained by evaporation. In this way the that the impurities separate out in the solid purified gas is separated into its constituents form possessing little or no vapor tension, and a certain quantity of the carbon mo separating the purified gas into its cont 25 stituents, mixing the carbon monoxid thus noxid thus obtained is mixed with the hy. obtained with hydrogen in the required 60 drogen so that these two gases are present quantity and passing the mixture into con in the required quantities, and the mixture. tact with a lheated catalytic substance for entirely freed from the impurities which the purpose set forth. were present in the commercial gas, is passed In testimony wheréof, we affix our signa 30 over heated and finely divided nickel in tures in presence of two witnesses. order that it may be converted into methane. FRED. BEDFORD, It is to be noted that nitrogen is not an im CHAS. ED. WILLIAMS, purity in the sense hereinbefore referred to, Witnesses: and it is immaterial, so far as the catalytic W. WARREN TRIGGs, 35 activity of the nickel is concerned, whether P. A. OUTHWAITE.