Metal-organic framework structures: adsorbents for natural gas storage

Abstract

Natural gas (methane) forms an essential part of modern power supply. However, natural gas storage and transportation are associated with fire and explosion hazard, which restricts extensive application of natural gas as a fuel. The adsorption technique is among the most promising and safe ways for natural gas storage and transportation, which allows a significant increase in the methane density up to values characteristic of liquids as a result of physical adsorption in microporous adsorbents at moderate pressures. The review considers adsorption systems for natural gas (methane) storage based on metal-organic frameworks, which possess high characteristic energy of adsorption and a regular nanoporous structure with high pore volumes and specific surface areas. The possibility of controlling the porous structure and physicochemical behaviour of metal-organic frameworks during their synthesis and functionalization is analyzed, including the fabrication of composites and shaping, which may enhance their performance in the adsorption storage and transportation of natural gas. The bibliography includes 315 references.

Thermodynamics of Adsorbed Methane Storage Systems Based on Peat-Derived Activated Carbons

“…It should be noted that the utilization of these materials for the ANG storage systems implies that they meet the requirements imposed on these systems. Among these requirements are chemical stability, mechanical strength, thermal stability, conductivity, minimized affinity to water, and heavier natural gas components (ethane, propane, and butane), accessibility and simplicity of the synthesis, and low costs of reactants and final product [ 2 , 9 ]. Although MOFs show high promise in this area, their use in the loose powder form with low packing density produced by most conventional synthetic techniques is not practical in the ANG systems, and, therefore, they must be shaped [ 12 , 13 ].…”

Adsorbed Natural Gas Storage for Onboard Applications

“…The use and transport of NG have been facilitated by compression (CNG) and liquefaction (liquified natural gas, LNG). [ 18,37 ] ANG has also emerged as an alternative for portable NG. [ 16,18 ] Herein, the advantages and disadvantages of these methods are discussed and summarized in Table 1 to highlight ANG's potential for onboard applications.…”

“…CNG is a prominent form of NG storage where NG is compressed to 20–30 MPa via a multistage compression process before being stored in high‐strength tanks at room temperature. [ 18,35,37–39 ] Hence, the density of CNG is about 230 times greater than that of NG under ambient conditions. [ 35 ] In a CNG system, the compressor is the main energy‐consuming equipment.…”

“…[ 32 ] Yet, despite improvements to the cylindrical storage tanks, the VED of CNG (8.8 MJ L −1 at 20 MPa and 293 K) remains low at about 25–27% the VED of gasoline. [ 18,34,35 ] There are also practical disadvantages to CNG in terms of i) the challenging maintenance of the multistage compressors and refueling systems, [ 26,34,37 ] ii) the limited portability of the strong and thick‐walled cylindrical or spherical storage tanks (weight of CNG kit may be more than 100 kg), [ 26,34,37,38 ] and last but not the least, iii) the difficulty in quality control as the composition of NG varies. Furthermore, the introduction of moisture and nonmethane hydrocarbons during compression could adversely affect the engine performance.…”

Graphene Oxide Protected Copper Benzene-1,3,5-Tricarboxylate for Clean Energy Gas Adsorption

“…As an efficient CO 2 adsorbent, this MOF can adsorb CO 2 from 2.5 to 4.2 mmol·g −1 under atmospheric conditions [ 10 , 11 ]. In terms of methane and hydrogen adsorption, it is still one of the most promising adsorbents among several MOFs [ 12 , 13 ]. Its methane adsorption performance is close to the volumetric US DoE (Department of Energy) target (263 cm 3 CH 4 /cm 3 MOF at 35 bar) established for economical natural gas storage [ 14 , 15 ].…”