Patent ID: 6444014
Filing Date: 2002-09-03
Classification: B01D,B01J,Y10S

Abstract:
A process for the separation of nitrogen from a feed gas including nitrogen, said process comprising: contacting the gas in an adsorption zone with an adsorbent that is equilibrium selective for nitrogen and adsorbing nitrogen on said adsorbent, wherein said adsorption zone comprises an equilibrium selective adsorbent material selected from the group consisting of A-zeolite, Y-zeolite, NaX, mixed cation X-zeolite, chabazite, mordenite, clinoptilolite, silica-alumina, alumina, silica, titanium silicates, phosphates and mixtures thereof; and wherein said adsorbent has properties defined by the hyperbolic function:(SCRRâˆ’0.22)*NML FoM&gE;2.5; wherein SCRR=RR*(dparticle)2; RR=&Dgr;N2(YF, Y0)/(t2âˆ’t1); &Dgr;N2(YF, Y0)=[N2 Loading at p, YF]âˆ’[N2 Loading at p, Y0] at 300K; YF, Y0, Y2 and Y1 are mole fractions in the gas phase, and t2 and t1 are the times corresponding to Y2 and Y1 in the concentration front; dparticle=the Ergun diameter of the adsorbent particle; NML FoM=[&Dgr;N2(T,B)]*[&agr;T(N2/O2)]2/[&agr;B(N2/O2)] as measured at 300K; &Dgr;N2(T,B)=[N2 Loading at pT, XT]âˆ’[N2 Loading at pB, XB]; &agr;T(N2/O2)=[XT(N2)/XT(O2)]/YT(N2)/YT(O2)]; &agr;B(N2/O2)=[XB(N2)/XB(O2)]/YB(N2)/YB(O2)]; subscript T denotes the highest adsorption pressure, and subscript B denotes the lowest desorption pressure; XT and XB are mole fractions of the indicated molecules in the adsorbed phase at the pressure denoted by the subscript; and YT and YB are mole fractions of the indicated molecules in the gas phase at the pressure denoted by the subscript.