Session 5 - Oral 13
Experimental study on kinetics of methane storage in coal slurry hydrate
Junhua Peia,b, Liang Yanga,b,*, Han Hua,b
a School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
b Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
ABSTRACT：Surface-active coal slurry (SCS) was prepared by blending micro-pulverized coal in sodium dodecyl sulfate (SDS) solution at a high speed. The free-flowing slurry is essentially a coal water mixture with surface activity, high calorific value and considerable free water. The water in the SCS can further capture methane in the form of hydrate to elevate energy density of the coal slurry. Uniformly dispersed coal particles with rough surfaces in the slurry can provided a large number of crystallization sites for hydrate nucleation. In order to investigate the kinetics of methane hydrate formation in coal slurry, methane consumption experiments were conducted in a stainless steel vessel without stirring at 6.0–8.0 MPa and 274.15 K. The results demonstrated that the active slurry facilitated rapid methane storage in clathrate hydrate, and the energy density of the coal slurry had been significantly improved. At the high pressure (8.0 MPa), 5.0 wt% coal of the SCS exhibited the maximum methane storage capacity of 167.6 cm3·cm-3 and the maximum storage rate of 28.09 cm3·cm-3·min-1. By contrast, the gas storage performances of the samples with higher coal concentrations of were not satisfactory due to the reduction of free water content. Especially, no hydrate was formed in the sample with the concentration of 35.0 wt% coal. At the applied pressures, the storage capacities of SCS were increased by 6.5%–24.6%, and the storage rates were increased by 8.6%–53.0%, compared with that of SDS solution. Moreover, the energy density of the binary fuel surpassed that of traditional coal slurry with the same coal concentration, and the SCS with the concentration of 30.0 wt% coal has the highest energy density of 11.36 MJ kg-1. The development of the new hybrid fuel is expected to reduce the use of coal and promote comprehensive utilization of fossil energy.
Keywords: methane storage, coal slurry, hydrate formation, kinetics, energy density