Effects of Additives on Coke Reactivity and Sulfur Transformation during Co-pyrolysis of Long Flame Coal and High-Sulfur Coking Coal

Abstract

A silica-aluminum-based mineral (GL) was selected for inspecting the effects of interactions of minerals in coal blends on the coke reactivity index (CRI) and sulfur transformation during co-pyrolysis of long flame coal and high-sulfur coking coal. Results indicate a good compatibility for the supply of active hydrogen, decomposition of sulfur, and regulation of reactivity. The experimental values of sulfur content in different coal blend cokes are lower than the calculated values, which can be determined as a result of the directional regulation effect of long flame coal on sulfur transformation. The addition of GL in coal blends significantly reduces the CRI of the corresponding coke, and the effect of GL on coke reactivity is also verified by a 10 kg coke oven experiment. When increasing the ratio of long flame coal, the sulfur fixation in the solid phase has a tendency to be enhanced by alkaline minerals. Also, GL plays a role in reducing the capture of sulfur free radicals by alkaline minerals, which improves the sulfur removal during pyrolysis of coal blends and then reduces the sulfur content in coke. This work provides a reference for using silica-aluminum-based minerals to reduce the capture of sulfur and catalytic effect on coke reactivity.

Effect of Kaolin on the Thermal Conversion Performance of Zhundong Sub-bituminous Coal

“…This addition has been known to increase the SiO 2 content in C-ZSBC as reported in previous studies. Moreover, Figure a shows two peaks that can characterize the microcrystalline structure of the material: the (002) peak, which represents the degree of orientation of macromolecules in the aromatic plane at 22–24°, and the (100) peak, which represents the size of the aromatic plane at 44°. , Following the addition of kaolin, the intensity of the (002) peak in C-ZSBC decreases. This suggests that the addition of kaolin disrupts the directional arrangement of aromatic plane macromolecules, leading to an increase in the degree of disorder .…”

“…Notably, the γ peak appears on the left side of the (002) peak. This peak is the aliphatic side chain connected by the edge of the microcrystal, which results in the asymmetry of the (002) peak. , …”

“… 35 The absorption peak at 470 cm –1 is attributed to kaolinite, resulting from the asymmetric expansion of Si–O–Al and the bending vibration of O–Si–O. 35 Since kaolin mainly consists of kaolinite, 36 the stronger peak intensity observed in C-ZSBC-K compared to C-ZSBC suggests a higher kaolin content in C-ZSBC-K.…”

“…This peak is the aliphatic side chain connected by the edge of the microcrystal, which results in the asymmetry of the (002) peak. 36,37 The microcrystalline structure parameters of both C-ZSBC and C-ZSBC-K are calculated using the Bragg equation and Scherrer formula. 37 Table 5 presents the calculated microcrystalline structure parameters where d 002 represents the interlayer spacing, L c refers to the stacking height of the layer, and L a represents the diameter of the layer.…”

Study on the Effect of Pyrolysis Conditions on the Combustion Behavior and Char Structure Evolution

“…The large background intensities presented in all of the diffraction peaks revealed the existence of amorphous carbon in all char. 42,43 The broad 002 band at 20−30°characterized the stacking in aromatic layers of char crystallites, and the 100 band at 40−50°represented the hexagonal ring structure in crystallites. 44,45 The microcrystalline structure parameters for all of the char samples are summarized in Table 8.…”