Papers by Author: Xin Zhe Lan

Abstract: The microwave pyrolysis is a new research method for deeply processing of coal. This paper researched the microwave pyrolysis products of low rank coal under N₂ and non-N₂ atmosphere. The results showed that, compared with non-N₂ atmosphere, the yield of liquid products increased by 4.65%, while the yield of solid bluecoke decreased by 2.95% under N₂ atmosphere. The infrared characteristics absorption peak intensity of bluecoke obtained from N₂ pyrolysis atmosphere was weaker; N₂ contributed to the transformation of heavy oil into light oil.

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: The aim of this paper is to contrast the effect of the microwave heating and traditional heating leaching vanadium from stone coal with sulfuric acid solution, contrast the leaching rate of vanadium, kinetics of leaching vanadium and the phase change s of slag. The experiment results show that the leaching rate and leaching velocity of vanadium with microwave heating was higher greatly than traditional heating, the kinetics of leaching vanadium with two heating methods was similar and accords with unreacted core contraction model with have solid product layer model, the illite in the stone coal was decomposed with microwave heating, but the traditional heating could not decomposed.

Abstract: The effect of different factors, such as carbon fiber content, temperature, electrifying time and frequency, power density on the electrothermal properties of the composite papers with different carbon fiber content was researched. The results show that the resistivity of the composite papers decreases with the increasing of carbon fibers. The current-voltage relationship is in good conformity with the Ohm's law. The negative temperature coefficient and good reversibility are shown during the heated and cooled process of the papers. The resistance of the papers decreases gradually with electrifying time and trends to stable after several hours. On-off electrifying times on its resistance have little effect in the long term. The curve of power density and surface temperature shows a good linear behavior.

Abstract: This paper investigated synthesis of Lanthanum oxide nanoparticles by precipitation method. Effects of reactant concentration, precipitator and dispersant agent on properties of Lanthanum oxide particles were studied. Lanthanum oxide particles were characterized by XRD and SEM. Experimental results showed that ammonium bicarbonate and PEG20000 were appropriate precipitation and dispersant respectively. The optimum process conditions were as follows: concentration of Lanthanum nitrate was 0.18mol/L, concentration ammonium bicarbonate of was 0.6mol/L, reaction temperature was 30. The average particles size of Lanthanum oxide powders with spherical shape gained was about 188 nm.

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: Vacuum annealing was carried out for the SMAT treated CP-Ti sample at different temperatures. The structure and the properties of the SMAT sample before and after the annealing were analyzed by means of the optical microscope, hardness and polarization curve testing. The results show that, when the annealing temperature of surface nanocrystallized CP-Ti treated CP-Ti (SMAT) was below 350°C, the microstructure and hardness of nanostructured surface was stability, and its corrosion resistance was improved compared to non-annealing one. In particular, the corrosion resistance at 150°C was better than that of the original CP-Ti.