Fundamental studies on hydrogasification of Taiheiyo coal

Effect of calcium additive on product yields in hydrogasification of nickel-loaded Chinese sub-bituminous coal

“…Mechanism of the coal hydrogasification proposed by Jüntgen [28] shows that coal pyrolysis produces radicals (-CH 3 , -CH 2 from the C-C bridges, O from other bridges and larger ring systems containing some free radicals) by cracking the bridge carbons that have the lowest bonding energies and dissociating the aromatic ring units. CH 4 , HCL, Tar, H 2 O and C 2 -C 3 hydrocarbons are generated by the recombination of radicals and their reaction with hydrogen, CO x is produced by cracking of the carboxyl groups and phenolic groups. The main pathways of hydrogasification including consecutive and parallel are given below: (C and H are used as symbols and not in the strict meaning of stoichiometry).…”

“…Currently, a lot of research has been performed on coal hydrogasification under a high hydrogen pressure and temperature [1][2][3][4][5][6][7][8][9][10][11][12][13]. The yields of gas and light hydrocarbon depended on coal type and reaction conditions [2].…”

“…The yields of gas and light hydrocarbon depended on coal type and reaction conditions [2]. The HCL products reached maximum value at 800-850°C [4,5]. Maximum CH 4 yield was obtained at hydrogen pressure of 7 MPa [7].…”

Potassium catalyzed hydrogasification of low-rank coal for synthetic natural gas production

“…Thus, despite the importance of alkali metals chemisorption and the extensive research performed on catalytic hydrogasification [20][21][22][23][24][25][26][27][28][29][30] major uncertainties still exist, regarding the origin and the mechanism of the CEC, its correlation with the pH and the oxygen functional groups. In addition, important issues such as the conditions of the coal-catalyst system preparation, the nature and the role in the catalysis of the cation and/or the anion, and the mechanism of the catalysis etc.…”

“…The mainframe of the proposed mechanisms [12,[20][21][22][23][24][25][26][27][28][29][30] for the catalytic activity of potassium in coal hydrogasification might be classified in four major groups. Thus, the first group of mechanisms considers that potassium might act as hydrogasification catalyst by hampering of coal agglomeration, while, the second states that potassium forms K-O-C complexes that enhance the reaction with H 2 at the inactive "zig-zag" <1120> graphitic plane.…”