Papers by Author: Yong Hui Song

Abstract: This study examined the co-pyrolysis characteristics of low-rank coal (SJC) and direct coal liquefaction residue (DCLR) through thermogravimetric analysis coupled with Fourier transform infrared spectrometry. It also investigated the influences of different mass fractions of DCLR to SJC on the co-pyrolysis characteristics and release regulation of gas phase components. Results showed that with increasing DCLR content, coke yield initially decreased and then increased, but tar and gas yield reversed. Different addition of DCLR changed the composition of the pyrolysis gas in various degrees, and reduced the content of-OH and nitrogen compounds in coke. The H₂ content in the gas gradually increased. When 40% DCLR was added, the maximum tar yield was 22.79%, and the maximum H₂ yield was 37.12%. At 60% DCLR, the lowest semi-coke yield was 65.01%, and the highest gas yield was 14.65%. The co-pyrolysis of SJC and DCLR can be divided into three stages. The first was the dry degassing stage, during which the adsorbed gas and small-molecule gas were removed on the coal surface at room temperature to 350 °C. The second stage (350 °C–650 °C) was the intense pyrolysis reaction stage, during which a large number of volatiles were obtained. The substantial weight loss rate peak appeared around 450 °C. The weight loss rate of pyrolysis gradually increased with increasing DCLR dosage. The co-pyrolysis of SJC and DCLR was not a simple sum between SJC and DCLR, which indicated a synergistic effect in the co-pyrolysis. The synergistic effect between SJC and DCLR enhances the interaction between free-radical fragments, thereby increasing the yield of pyrolysis tar. The third stage was the shrinkage of semi-coke from 650 °C to the end of the reaction. The polycondensation reaction between free-radical fragments to form solid coke with higher aromaticity, and H₂ released.

Abstract: Microwave pyrolysis of low rank coal is a new technology of cleaner production. The effect of microwave power and flow rate of N₂ on the yield of pyrolysis products under N₂ atmosphere was explored. The results showed that the higher microwave power was, the higher all the terminal temperature, the yield of liquid products and the weight loss rate were. The flow rate of N₂ had little influence on the yield of pyrolysis solid products, while it exerted a greater influence on the yield of pyrolysis liquid products. When the low rank coal was pyrolysised under the conditions of microwave power of 800W and flow rate of N₂ of 4.0×10^-4 m³/min, the yield of Bluecoke and liquid products respectively reached 65.8% and 18%.

Abstract: In this paper, conventional pyrolysis (CP) and microwave pyrolysis (MWP) for three types of low rank coal in western China was studied. The effects of pyrolysis methods and temperature etc on product yields were also discussed. Pyrolysis products were characterized by IR, Gas analysis meter and GC-MS. Results showed that the tar and gas yields in microwave pyrolysis is about 3%-5% higher than those in the conventional pyrolysis. H₂ and CO proportions in gas are above 55%. The contents of benzene, aromatic hydrocarbon and phenolic compound in microwave pyrolysis tar are higher than those in the conventional pyrolysis, in addition, C5~C10 substance content in tar is about 5 times as that in the conventional, so the microwave pyrolysis can prompt tar converting to light fraction.

Abstract: Microwave pyrolysis of coal is a new research method for deeply processing of low rank coal. This paper conducted comparative study on microwave co-pyrolysis products of low rank coal in CO₂ and N₂ atmosphere. The composition and content of tar and bluecoke were analyzed by gas chromatography-mass spectrometry and FTIR spectroscopy. The results showed that the yields of liquid products in CO₂ and N₂ atmosphere were 20.6% and 18.0% respectively, and the yields of bluecoke were 62.0% and 65.8%. Bluecoke obtained from CO₂ pyrolysis atmosphere had the lower content of fixed carbon and oxygenic functional groups, but the higher content of volatile. There was the lower content of aromatic hydrocarbons and the higher content of oxygenic functional groups in the tar produced in CO₂ pyrolysis atmosphere due to CO₂ gasification effect.

Abstract: Bluecoke is a new type carbon product that prepared by low temperature carbonization process, which take lignite, long flame coal, not sticky and weak glue coal as raw material. At the same time tar and coke oven gas as by-products can be obtained. Two new technologies of Bluecoke production were introduced based on summary of way of producing Bluecoke by low metamorphic coal, namely the rich oxygen carbonization and the microwave carbonization. Both ways have their advantages and disadvantages. By contrast, the quality of coke and the content of valid gas are better using microwave carbonization, which to follow-up industry chains development significantly.

Abstract: This paper describes the products characteristic derived from the conventional pyrolysis (CP) and microwave-assisted pyrolysis (MWP) of low metamorphic coal. GC/MS were used to analyze the volatile fractions of tar obtained by pyrolysis at different temperature and microwave power. It was found that microwave treatment produces more gas and oil than conventional pyrolysis at 800w and 800°C. In addition, the gas from the microwave has much higher syngas (H₂ + CO) contents (up to 55 vol. %) than those obtained by conventional hydrolysis (up to 42 vol. %). The tar from the microwave is mainly composed of aromatic pyrolysis and phenolic compounds, and the content is 47.398% and 13.831% respectively as the microwave power is 800w. Meanwhile, the tar component content of C₅-C₁₀ from microwave pyrolysis is up to 5 fold than conventional pyrolysis. By contrast, the microwave-assisted pyrolysis is beneficial to the tar conversion to light fraction.

Abstract: The pyrolysis characteristics of Jianfanggou(JFG) coal was studied using a thermo-gravimetric analyzer and the pyrolysis kinetic parameters were calculated at the different heating rate. The results showed the DTG curves under different heating rate had three peaks and the corresponding temperature were 100°C, 470°C and 750°C, the pyrolysis process can be divided into three stages conclusively. The maximum weight loss rate at 470°C indicated the major weight loss occurred in the second stage. The T_b, T_f and T_∞ obtained under experiment situation. The results of the JFG coal pyrolysis kinetic showed the T_b, T_f and T_∞ increased gradually with the accretion of the heating rate. In the meantime, the variation of frequency factor was consistent with the trend of activation energy.

Abstract: The flower-sphere molybdenum disulfide has been synthesized by reaction of Na₂MoO₄ and CS(NH₂)₂ with NH₂OH·HCl or H₂C₂O₄ as reductant. The microstructure and chemical composition of the product were characterized by means of X-ray diffraction and scanning electron microscope. XRD patterns showed that the molar ratio of Mo to S had a great effect on the purity of the product. When the molar ratio of Mo to S was 1:5, the product was nearly pure MoS₂. SEM images showed that the particle size increased as the molar ratio of Mo to S reduced. The MoS₂ microspheres had rough surfaces and were constructed with sheet-like structures in the two systems. But the product from the system of NH₂OH·HCl as reductant has the bigger particle size, clearer petal-sheets, coarser surface and weaker agglomeration than that from the system H₂C₂O₄ as reductant. The possible chemical reactions in hydrothermal systems were preliminarily discussed.

Abstract: The flake-like silver nano-particles were prepared by reducing silver nitrate with hydrazine hydrate in the sodium dodecyl benzene sulfonate (SDBS) and Polyvinyl pyrrolidone (PVP) complex solution. The as-received silver powders were characterized by SEM, EDS, TEM and XRD methods. The effects of SDBS and PVP with Ag⁺ ligand on the preparation of flake-like shape were analyzed. The results provide evidence that the SDBS-Ag⁺ ligand play a limiting template role during the silver growth and leading to the formation of flake-like silver consequently.

Abstract: Vanadium is an important alloying elements and structural materials, a large part of vanadium was extracted from stone coal. The resources of stone coal are very rich in China. It's an important development direction to extract vanadium in stone coal. The stone coal in Shaanxi Province Shanyang County has been studied. Vanadium was extracted by HDEHP in this experiment, which is in the sulfuric acid solution leaching system. The paper researched the influence of concentration of di(2-ethylhexyl) phosphate (HDEHP), pH, the extraction time, the extraction stages, the phase ratio for the extraction ratio of vanadium, the extraction capacity of organic phase and the extraction isotherm. The best technical parameters: 20% di(2-ethylhexyl) phosphate (HDEHP), TBP 5%, sulfonated kerosene 75%(volume concentration), pH=2.5, phase ratio Vo:Va=1:5 and the extraction time is 5 min, extraction of 5 stages level. The extraction ratio of vanadium is 98.57% from the solution of 2.9658 mg/ml vanadium in that technical parameter. The best stripping of vanadium process parameters: the stripping agent for 1 mol/l of sulfuric acid, phase ratio Vo: Va = 5:1, the stripping time is 5 min, the stripping of three stages. Under this condition we may strip loaded organic phase which contain the vanadium 9.0266 mg/ml, the stripping rate is 99.73%.