July, 1925
INDUSTRIAL A N D ENGINEERING CHEMISTRY
715
Solubility of a Mixture of Hydrogen and Nitrogen in Liquid Ammonia' By Alfred T. Larsen and Charles A. Black FIXEDNITROGL~H RESEAR&LABORATORY,
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T H E direct synthetic The solubility of a mixture of hydrogen and nitrogen (dead-wekht) g a g e . T h e (3 : 1) in liquid ammonia has been determined throueh rate of flow of gas through the ammonia Process the rem o d of ammonia from a temperature range -25.2" to t22.0"C.and at pressures bottle was controlled by of 50, 100, and 150 atmospheres. The temperature means Of a needle valve atthe high-pressure system iS tached to the exit b. frequently accomplished by coefficient is positive. The solubility of the 3: 1 mixture of hydrogen and nitrogen more than doubles with a The steel bottle Was corncooling the gas mixture to a 500 C. rise in temperature. The pressure effect conpletely immersed in a ]OWtemperature a t which amforms closely to Henry's law of gas solubility. temperature thermostat, the m o n k liquefies. It has been temperature of which was conobserved that the liquid amtrolled by means of an ammonia withdrawn carries with it an appreciable amount of dissolved nitrogen and hydrogen, monia expansion coil placed in the thermostat liquid. The temthe presence of which in some instances, notably refrigeration, perature within the bottle was measured by means of an iron is undesirable. With the exception of a study by Schulbach constantan thermocouple inserted in the pyrometer well, c. and Ballauf,*who examined the solubility of hydrogen in am- The bottle was provided with a by-pass, d, which made it possimonia a t -70" C. and one atmospherepressure, there has been ble to reverse the position of the inlet and outlet, a and b. OPERATION-An ammonia-nitrogen-hydrogen mixture from no systematic investigation of this phenomenon. Since these results do not furnish a satisfactory basis for computing the the catalyst bomb was passed through the cold bottle, where solubility of a mixture of nitrogen and hydrogen in ammonia, part of the ammonia condensed to a liquid. The ammonia particularly a t high pressures, a further study has been deemed content of the affluent and of the effluent gas and the rate of flow through the bottle being known, an estimate of the voladvisable. ume of liquid collecting in the bottle was made. When T about 100 cc. of liquid had been collected, the temperature of the thermostat waq carrfully adj constant for a t least one-half hour before a n y s a m p l e s were taken. Preparatory to the removal of the l i q u i d s a m p l e the valves were set so that the pressure formerly applied a t a was now applied a t b. This made it possible to maintain a constant pressure on the bottle during the withFigure 1-Steel Container and Connections for Determining Soldrawal of the iquid ubility of Nitrogen and Hydrogen sample. The connecIn Liquid Ammonia tion between valves ni and nwas then broken and the valve n attached to anammonia The experimental method consisted essentially in passing a &sorption apparatu.. mixture of hydrogen and nitrogen (3:l) through a wash since the tube atbottle containing anhydrous ammonia. Samples of liquid tached to the valre 12 ammonia were withdrawn from time to time and analyzed dipped below the for nitrogen and hydrogen. face of the liquid am-~PPARATUS-I~ cross section of the wash bottle (volume mania, the open valve 200 cc.) is shown in Figure 1. The inlet a was connected to a permitted liquid to be high pressure synthesis system producing about 12 per cent forced Over illto the of a n i m ~ n i a . The ~ pressure within the bottle was regulated absorption apparatui. by means of an electrically operated reducing valve.4 A The absorption apBourdon tube type gage indicated Auctuations in pressure and the actual pressure was determined by means of a piston type paratus into uThich the liquid ammonia 1 Received February 6 , 1925 was expanded i i * Ber , 64, 2825 (1921) shown diagrammati- termining Figure 2-Absorption Apparatus for De3 Tour, Chrm MPI E m , 26, 588 (1922) Ammonia in Ammonia-HyLarson and Karrer THIS J O U R N A L , 14, 1012 (1922) tally in F i g u r e 2 . drogen-Nitrogen Mixture
believed to be too small to affect appreciably the values determined for the solubility of nitrogen.
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