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The volatile organic compound (VOC) emissions from the pyrolysis of anthracite and bituminous coals are studied using both online single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) and offline gas chromatography/mass spectrometry (GC/MS) techniques. It is found that the combination of the online and offline techniques is effective in the VOC analysis. It reveals that the dominant pyrolysis products of both anthracite and bituminous coals are comprised of a mixture of non-aromatic hydrocarbons, mainly alkanes and light alkenes, aromatic compounds, and their corresponding isomers. Rank variation of coal samples has important impacts on the release of pyrolysis products. High-volatile bituminous coal releases more VOCs than low-volatile anthracite coal under the same temperature. The relative contents of the pyrolysis products of the two coals also differ. SH coal releases more short-chain aliphatic and oxygen-containing compounds, while XT coal releases more aromatic and sulfur-containing compounds. The temperature has an important influence on the release of VOCs from coal pyrolysis. The relative signal intensities of most products increase as the temperature increases. According to the time-evolved spectra, the higher the temperature, the earlier and faster the release of VOCs, regardless of the coal type. For both coals, the release of most VOCs is favored at higher temperatures. For bituminous coal, at a fixed temperature, almost all alkenes and dienes started to release at approximately the same time, except propylene, which has two peaks, indicating that there may be two steps in the release of this compound. The aromatics were released a little delayed, especially at low temperatures.

This paper presents an enhancement method to improve the desulfurization performance of wet flue gas desulfurization (WFGD) by adding a flow pattern controlling (FPC) device in the spraying tower. The FPC device is characterized by a modular design and composed of FPC units that are fixed under the spraying layers of the desulfurization tower. Two kinds of FPC units, each with a different scale, are designed (i.e., unit A and unit B). The effects of the FPC unit and operational parameters on the desulfurization process are determined by experimentation. The experiments show that the FPC unit significantly improves the desulfurization performance compared to the common spraying column without an aperture plate. The flow regime significantly changes and large amounts of bubbles develop above the perforated plate in the FPC unit, which is beneficial to enhance gas–liquid mass transfer. The design style and structural parameters of the FPC unit both significantly influence the desulfurization performance. According to the results, optimal desulfurization performance is achieved with four holes and an aperture ratio of 0.65 for unit B. For L/G= 10 L/m3, the desulfurization efficiency of unit B reaches 77% (approximately 22% increase) with a pressure increase of 370 Pa. The relationship between the operational parameters and the different scale units is investigated under different test conditions. In addition, the results show that the range of improvement with the perforated plate is related to the gas–liquid flow regime in the unit. Finally, we attempt to build an empirical correlation formula of each influence factor on desulfurization efficiency and pressure drop based on the experimental results.

Unmined and undisturbed coal seams are considered favorable areas for CO2storage. Studying the adsorption behavior of CO2/CH4in carbon structures is critical to provide information for CO2sequestration and gas exploitation. Here, three carbon structure models with different fringe lattices (curvature, planar, and a mixture lattice with curvature and planar) were constructed using an amorphous cell module in Material studio. The simulated densities of the curvature, planar, and mixture models were 1.4, which is within the range of the experimental density of coal. The adsorption behaviors of CH4, CO2, and their mixtures in the constructed models were investigated using the grand canonical Monte Carlo method. The results show that the absolute adsorption amount increases with the increasing ambient pressure and decreases with the increasing ambient temperature. The isosteric heat for adsorption of CO2in three models is higher than that of CH4. The absolute adsorption amount of CO2/CH4in the curvature model is higher than that in the other models, but the absolute adsorption amount of CO2molecules is superior to that of CH4at the same pressure and temperature. The adsorption sites for CO2/CH4are concentrated in the pore space in the saturated adsorption state, and the saturated adsorption amount in the three models follows the sequence of curvature > mixture > planar. The pore width in the planar model shows a peak at 3–3.5 Å, whereas that in the mixture structure shows two peaks at 2.6–3.4 and 3.5–4.4 Å. However, the curvature model has wide intervals at 2.6–3.4 and 3.4–4.6 Å. The radial distribution function indicates that CH4/CO2prefers to be adsorbed on C4 (sp3, generic 4 bonds) and C3a (sp2, double bond to C, C═C) and preferentially occupies the sites of curvature.