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Activated carbon (AC) serves as a porous matrix suitable for thermochemical energy storage applications. This study explores the impact of the porous structure of AC on water adsorption, reaction kinetics, heat storage density, and cycling stability in AC-CaCl2composites (AC/Ca). Findings indicated that increases in pore volume directly enhanced the CaCl2content, water absorption, and heat storage density of the composites. Among the samples studied, the mesopore-dominant AC3/Ca with the largest specific surface area and pore volume exhibited an impressive heat storage density of 2981 kJ·kg−1with a water uptake of 1.07 g·g−1after 4 h of hydration. Furthermore, the water uptake remained at 89.76 % after 25 cycles. Additionally, a kinetic study of four AC/Ca composites was conducted to further examine water adsorption; it revealed that water adsorption occurred via intra-particle diffusion within the AC pores. This study provides valuable insights into the design concept of porous matrices for high-energy-storage composites, which can have significant implications for TES applications in the building sector.

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.

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.