Tailoring Porosity Development in Monolithic Adsorbents Made of KOH-Activated Pitch Coke and Furfuryl Alcohol Binder for Methane Storage

Abstract

A series of microporous carbon powders of Brunauer-Emmett-Teller (BET) surface area ranging from 1900 to 2700 m 2 /g was made from pitch-derived semi-cokes by KOH activation at 750 °C. The powders were compacted into disk-shaped monoliths using a furfuryl-alcohol-based binder. Activation with CO 2 was used to open an access to the microporosity that was blocked by the binder char. The porous texture of monoliths was characterized by the N 2 adsorption at 77 K and mercury porosimetry, and the volumetric storage capacity and delivery V/V was determined from the methane uptake at 25 °C and 3.5 MPa. The results suggest that there is an optimum in porosity development of activated carbon powder and monolith burnoff from the point of view of the monolith performance in volumetric methane storage. The highest adsorption capacity and delivery V/V, which amount to 163 and 145, respectively, represents the monolith made of activated carbon of moderate porosity development (S BET ∼ 2200 m 2 g -1 ) that was activated to the burnoff of about 10%. † This paper has been designated for the special section Carbon for Energy Storage and Environment Protection.

Characteristics of Methane Adsorption in Micro–Mesoporous Carbons at Low and Ultra‐High Pressure

“…[16] Many research works on methane adsorption in carbonbased adsorbentsh ave been published,a nd al arge number of these works include high-pressure methane adsorption. Thel iterature data on methane adsorption at high pressure is limited to around 25 to 60 bar [17][18][19][20][21][22][23][24][25] and occasionallyu pt o 140-150 bars for coal-or shell-based low-surface-area materials [26,27] that are essentially sufficient for ANG technology. However, from as cientific point of view,t here are other interests in studying methane adsorption at extremely high pressures.F or example,a tv ery high pressure,m ethanec ould occupylarger pores and demonstrate unusual enthalpy of adsorption values.I ns pecific needs,f or example,f or long driving ranges or small tank volumes,h igh-pressure ANG tanks can provide higherm ethanes torage in al ess hazardous environmentc omparedt ocompressed bulk storage.…”

“…Many research works on methane adsorption in carbon‐based adsorbents have been published, and a large number of these works include high‐pressure methane adsorption. The literature data on methane adsorption at high pressure is limited to around 25 to 60 bar and occasionally up to 140–150 bars for coal‐ or shell‐based low‐surface‐area materials that are essentially sufficient for ANG technology. However, from a scientific point of view, there are other interests in studying methane adsorption at extremely high pressures.…”

Acid Mesoporous Carbon Monoliths from Lignocellulosic Biomass Waste for Methanol Dehydration

“…As can be seen, the preparation method here exposed allowed for obtaining circular shaped ACMs with axial channels, at very low pressure (0.8 MPa), in contrast to monolithic discs that were reported in the literature, which were obtained at 130 MPa [23,24]. Furthermore, most of these ACMs reported in the literature were usually made by compressing the already reported activated carbon in the presence of a binder, obtaining the corresponding ACM in the form of solid discs [25,26,27,28,29]. However, these binding components can produce a significant reduction in the porosity of the resulting monolith.…”

A Study of the Porosity of Activated Carbons Using the Scanning Electron Microscope

“…These methods almost invariably combine the adsorption isotherm of a given adsorbateadsorbent system and a theoretical or empirical model of the adsorption process to estimate the characteristics of activated carbons [Machnikowski, et al, 2010;Noor & Nawi, 2008;Lozano-Castello et al, 2004;Stoeckli et al, 2001Yuna et al, 2001Rodriguez-Reinoso, 1989]. Most commercial sorption equipment estimate activated carbon data using in-built software based on one version or the other of this approach.…”

“…To get quantitative data of a specimen from conventional SEM images, the practice is to convert the 2D images into 3D from which the requisite quantitative data can be measured or estimated often with the help of computerized image analysis software. A number of methods for getting 3D data from 2D images are available [Marinello et al, 2008;Spowart, 2006;Spowart et al 2003;Alkemper and Voorhees, 2001;Lyroudia et al, 2000 ]. These include stereology, photogrammetry, photometric stereo, and the more useful serial sectioning method.…”