The synthesis, characterization, and performance of a new low pressure, monolithic, activated carbon adsorbent developed for methane storage is discussed and compared to other adsorbents. The effect of particle packing density on the storage capacity of tanks filled with commercially available and developmental adsorbents is quantified. 20 kg of the developed monolithic material is tested using a custom built, 40 L, space conformable tank test assembly. The performance is found to be superior to metal organic frameworks and other activated carbons reported in literature based on high tank volumetric and gravimetric storage capacities. The developed material has a pore structure and external dimensions that allow for rapid adsorption/desorption with gas being able to reach the center of the 40 L tank within ~3 s. The developed material delivers 151 V/V of methane between 35 bar and 1 bar in the 40 L tank. A continuous discharge flow rate of 2 g/s at 5 bar for a 10 gge system was demonstrated. 42benefits outweigh its costs. 43The performance of an adsorbent is often 44 measured by collecting an excess adsorption 45 STP/cm 3 at 35 bar by Mason et al[8]) but this 106 material has a fragile pore structure making it 107 difficult to pack efficiently. In Mason's 108 work[8], STP is defined by 0 °C and 1 atm 109 giving a molar density of 0.0446 mol/L. 110 HKUST-1 tablets have a storage capacity of 111 67 g/L[8] which translates to an effective 112 packing fraction (i.e. calculated by using 113 equation 3 and assuming the pore structure is 114unchanged) of 0.31. Tap density 115 measurements (measured according to[22]) on 116 commercially available HKUST-1 produce a 117 packing fraction of 0.51. MIL-53 ( 118 , [8,23]) has a 119 bulk density of 0.4 g/cm 3 (when sold as 120 Basolite ® A100). This equates to a packing 121 fraction of 0.41 and a tank storage capacity of 122 55 g/L. It can be deduced that Tagliabue et 123 al[24] experienced similar packing results 124 (effective packing of 0.34) when trying to 125 densify Ni-MOF-74. Collectively, these 126 results suggest that many MOFs have large 127 crystalline storage capacities (e.g. 161 g/L) 128 but improved material packing methods are 129 required to improve the useable storage 130 capacity of these materials. 131 Experiments on PACs suggest that they can 132 be efficiently packed. Corn cob based KOH 133 PACs produced at the University of Missouri 134 (MU)[12,25,26] demonstrate tank volumetric 135 FIGURE. 14. Volumetric and gravimetric 595 storage and delivery comparisons between the 596 monoliths created here (Monolith-0311) and a 597

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IntroductionThis note reports the results of an experimental study of diffusion and reaction in a catalyst particle that has a radial profile of active ingredient (Pt) described by the function rn (1 -x)". The deuterium-neopentane exchange (DNE) reaction was employed in the study (Dwyer et al., 1968;Ernst and Daugherty, 1978;Ernst and Wei, 1975). The theory is based upon the work of Wei and Prater (1962) and Wei (1 962a, b). Ernst and Daugherty (1978) showed that the highly coupled system of rate equations which describe the behavior of Dexchanged hydride species such as neopentane can be uncoupled if the following transformation is made. Wang and Varma (1980) solved the intraparticle diffusionreaction problem for a catalyst pellet that has an activity profile described by the equation k ( x ) = m z ( 1 -x )~. Their solution,can be used to calculate the effectiveness factor for each bi species if the Thiele modulus is defined as @i = R The selectivity for the DNE reaction defined as the average number of D atoms in the initial hydride product (Kemball, 1954) was shown to be related to the effectiveness factor ratio (Dwyer et al., 1968)where n is the number of exchangeable hydrogen sites on the reactant hydride. (For DNE reaction studies, the t-butyl ion is observed rather than the neopentane molecule; therefore n = 9.) ExperimentalThe method of preparation of nonuniformly active Pt catalysts was described in a previous article (Shyr and Ernst, 1980). The method involved impregnation of y-alumina particles of spherical geometry with chloroplatinic acid solution containing the coingredients citric acid and NaBr, which modified the Pt profile. The catalyst support was gamma alumina (Rhone Poulenc Inc. Type GOD-30). Properties of the support include: particle dia. 0.36 cm; surface area, 150 m2/g; total pore volume 1.7 mL/g; and average pore dia., 450A (45 nm).A sample of catalyst from the preparation batch was examined by electron probe microanalysis (EPM) and found to have a radial profile of Pt that could be represented by the function m(1 -x)" where cr = 1.1The batch reaction system was a slightly modified version of an earlier system (Ernst and Wei, 1975). It consisted of a 500 mL spherical Pyrex reactor containing a porous pedestal for 0.04 (Hiltzik, 1983).

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