Progress in Studies of Natural Gas Storage with Wet Adsorbents

Abstract

Progress in natural gas storage with wet adsorbents is presented. The storage mechanism switched from adsorption for adsorbed natural gas (ANG) to hydrate formation when wet adsorbents were used. The activated carbon with a pore size of 1.6-3 nm was shown more suitable for the wet storage method, and a larger than 40 wt % gravimetric storage capacity and a deliverable capacity of more than 150 (v/v) were experimentally observed under conditions of 273-283 K and pressure ca. 8 MPa. The stored amount in wet carbon is 2 times higher than that of adsorbed and 1.5 times than that of compressed at the indicated conditions. All of the inherent technical drawbacks of ANG were overcome, and the storage pressure reduced more than half compared to compressed natural gas (CNG). Both investment and energy costs of fuel are expected to reduce, and the safety of the natural gas (NG) vehicle will improve radically.

Very high methane uptake on activated carbons prepared from mesophase pitch: A compromise between microporosity and bulk density

“…and similar pressure [26,27]. Thus, the storage capacity for methane of carbon sample PY56-8:1 800ºC is similar than the one reached for CNG at 20 MPa, but using half of the pressure.…”

Methane hydrate formation in confined nanospace can surpass nature

“…As described along the manuscript, previous studies have anticipated the beneficial effect of water in the methane adsorption capacity of activated carbons [19][20][21] . Although it has been speculated no evidence of methane hydrate formation has been described in the literature up to date.…”

“…Previous studies reported in the literature have anticipated the beneficial effect of water on methane adsorption, although a deep evaluation of the adsorption process (adsorption kinetics at different steps, phase identification, chemical stoichiometry and so on) and the adsorption mechanism responsible for this behaviour has not been clearly elucidated [19][20][21] . Figure 1b shows the methane adsorption isotherms for heavily water-supplied samples with higher R w ¼ 2.9 and 4.1 (oversaturated samples).…”

“…Despite the scarce number of studies dealing with methane adsorption on wet-activated carbons, to our knowledge, this is the first time that a two-step adsorption process can be discerned for activated carbons. Previous studies described in the literature have only described the sigmoidal shape at 4-6 MPa [19][20][21] . In addition to the two-step adsorption process, both samples exhibit a large hysteresis loop, the desorption branch being quite stable down to ca.…”

Hydrate Formation and Decomposition of CH4 and N2 in Ordered Mesoporous Carbon CMK-3 in the Presence of Tetrahydrofuran

“…5−10 Zhou et al have reported that using water-wetted carbon can promote the rate of natural gas hydrate formation, reduce the storage pressure, and save costs. 11 −13 In addition, the hydrates are easy to decompose, besides the filling and releasing rates are also improved. However, some problems still need to be studied.…”