A large amount of coal gasification slag is produced every year in China. However, most of the current disposal is into landfills, which causes serious harm to the environment. In this research, coal gasification fine slag residual carbon porous material (GFSA) was prepared using gasification fine slag foam flotation obtained carbon residue (GFSF) as raw material and an adsorbent to carry out an adsorption test on waste liquid containing methylene blue (MB). The effects of activation parameters (GFSF/KOH ratio mass ratio, activation temperature, and activation time) on the cation exchange capacity (CEC) of GFSA were investigated. The total specific surface area and pore volume of GSFA with the highest CEC were 574.02 m²/g and 0.467 cm³/g, respectively. The degree of pore formation had an important effect on CEC. The maximum adsorption capacity of GFSA on MB was 19.18 mg/g in the MB adsorption test. The effects of pH, adsorption time, amount of adsorbent, and initial MB concentration on adsorption efficiency were studied. Langmuir isotherm and quasi second-order kinetic model have a good fitting effect on the adsorption isotherm and kinetic model of MB.

There are increasing demands and great potential of coal gasification in China, but there is a lack of studies focused on the disposal and utilization of coal fly ash produced by the gasification process. In this study, a coal fly ash sample derived from a gasifier in Jincheng, China, was utilized as raw material for the synthesis of zeolite by alkali fusion followed by hydrothermal treatments. The effects of operation conditions on the cation exchange capacity (CEC) of synthesized zeolite were investigated. The synthesized zeolite with the highest CEC (270.4 meq/100 g), with abundant zeolite X and small amount of zeolite A, was produced by 1.5 h alkali fusion under 550 °C with NaOH/coal fly ash ratio 1.2 g/g followed by 15 h hydrothermal treatment under 90 °C with liquid/solid ratio 5 mL/g and applied in Ni²⁺ removal from water. The removal rate and the adsorption capacity of Ni²⁺ from water by the synthesized zeolite were determined at the different pH, contact time, adsorbent dose and initial Ni²⁺ concentration. The experimental data of adsorption were interpreted in terms of Freundlich and Langmuir equations. The adsorption of Ni²⁺ by the synthesized zeolite was found to fit sufficient using the Langmuir isotherm. More than 90% of Ni²⁺ in water could be removed by synthesized zeolite under the proper conditions. We show that the coal fly ash produced by the gasification process has great potential to be used as an alternative and cheap source in the production of adsorbents.

Inefficient residential solid fuel combustion contributes significantly to ambient and indoor air pollutants. It consumes large quantities of fuel and produces harmful effects on health. Improvements in residential biomass cooking stoves have great potential for energy savings and emission reduction. This study presents an advanced biomass gasifier cooking stove to overcome the disadvantages of high-pollutant emissions from widely used stoves in China. The most innovative features of the stove are (1) negative pressure produced by a jet fan located at the junction of the chimney, and (2) combustion and carbonization processes taking place in the same chamber. Compared with a traditional chimney stove, the advanced biomass gasifier cooking stove presented higher TE (thermal efficiency) and comprehensively lower pollutant emissions when raw crop straws, crop straw briquettes, and pellets were burned in it. Approximately 40% CO₂ and 90% of PM_2.5 (the aerodynamic diameter was less than or equal to 2.5 μm) EFs (emission factors) were eliminated, and TE drastically tripled. Furthermore, biomass briquette/pellet was identified as more suitable than raw biomass as a fuel to be burned in the new stove, especially because the raw biomass displayed an increase in the EFs of As, Se, and Pb when burned in the new stove. The advancement in biomass cooking stove technology is a practical approach to reducing the emissions of CO₂, PM_2.5, and other hazardous pollutants.

The entrained-flow gasifier has a better adaptability to various coals. The composition of coal ash is an important factor affecting the high-temperature flow characteristics of molten slag. Based on the SiO₂-Al₂O₃-CaO/Na₂O ternary phase diagram, the high-temperature molten flow characteristics of slag located in the main phase regions of feldspar, melilite, diopside, and mullite were investigated by experiments and thermodynamic software calculations. The results indicate that the melting process of ash in the three phase zones is influenced by different factors. It was discovered by infrared spectroscopy analysis that the slag was dominated by Si₂O₅^2- ion clusters in the feldspar region. The slag in the diopside region had a slightly higher proportion of simple silicate ion clusters than the slag in the feldspar region, resulting in better fluidity. This is significant for revealing the mechanism of coal ash melting and flowing and guiding industrial coal blending.

Coal tar pitch (CTP) is abundant and widely used, but its properties will be affected due to oxidation aging during storage. In this study, CTP was oxidized by simulating the air oxidation process, and the change of chemical structure has been analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and both gas chromatography and mass spectrometry (GCMS). The effects of the oxidized and unoxidized CTP co-carbonization with coal on the polycyclic aromatic hydrocarbons (PAHs) emission were detected by GCMS. The small and medium-molecule aromatic substances were reduced during CTP oxidation, while the intermolecular condensation reaction increased the macromolecules content. The catalytic can effectively facilitate the dehydrogenation and condensation reaction of CTP and the entry of oxygen molecules, which leads to the increase of oxygen-containing groups and the decrease of PAHs. Compared to the raw CTP, the catalytic oxidized CTP significantly reduced the emissions of toxic PAHs during the co-carbonization with coal. A possible catalytic mechanism of CTP catalytic oxidation is proposed.