Variable Pore Structure and Gas Permeability of Coal Cores after Microwave Irradiation

Abstract

The experimental work in this paper investigated the effect of microwave energy on pore structure and gas permeability of coal cores. Fifteen coal samples were irradiated under the condition of 2.45 GHz with 6 kW. The effect of microwave irradiation on the pore structure of coal samples was evaluated by nuclear magnetic resonance (NMR). The water saturation degree has little influence on transverse relaxation time (T2) distribution before the microwave treatment. By contrast, water saturation degree obviously affects the T2 distribution after the microwave energy treatment. Coal permeability increased after microwave energy treatment. But fractal dimension decreased after microwave energy treatment. The results show that microwave energy has a potential for degassing coal seams.

Simple and Fast Microwave-Assisted Synthesis Methods of Nanocrystalline TiO2 and rGO Materials for Low-Cost Metal-Free DSSC Applications

“…However, in the literature, there is no clear explanation or evidence on the effect of microwave irradiation time on the porosity of the solid samples. Our results are compatible with the previous work of Hong et al…”

“…However, in the literature, there is no clear explanation or evidence on the effect of microwave irradiation time on the porosity of the solid samples. Our results are compatible with the previous work of Hong et al 32 The pore size distribution is plotted in Figure 6, which is set by applying the methodology of Barrett−Joyner−Halenda (BJH). The calculated specific surface area, porosity (P), total pore volume (V p ), and maximum pore volume (P max ) for all the samples are given in Table 2.…”

“…Despite the fact that the overall power efficiency of the fabricated DSSCs based on rGO as the counter electrode is lower than that based on Pt electrode, the former still exhibits promising prospects for replacing Pt with low-cost metal-free carbon-based DSSCs. Different TiO 2 nanoparticles with different crystallite sizes from 21 to 36 nm have been synthesized via the microwaveassisted hydrothermal method at different microwave irradiation times (32,30,45, and 60 min).…”

Methane Seepage Characteristics in Coal Seams under Microwave Radiation

“…Jones reported that in response to different boundary volumes of particles to microwave energy, the ability of small particles to absorb microwaves is lower when the power density is constant. Hong , showed that the porosity of coal samples increased clearly after microwave heating. Moreover, the fractal dimensions of coal and rock decreased after the microwave energy treatment.…”