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Dong H.-Z.,Taiyuan University of Technology | Feng G.-R.,Taiyuan University of Technology | Guo Y.-X.,Taiyuan University of Technology | Qi T.-Y.,Taiyuan University of Technology | And 3 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2013

Goaf filling is the current efficient solution to solve mining subsidence and surface damage during coal mining. The filling material which is prepared with fly ash and coal gangue is pumped into the goaf through the pipe, which not only can provide the material source for filling, but also control the environmental pollution caused by coal gangue and fly ash disordered stacking from headstream. The pipeline transportation is one of the important links. As one of the key points in the design of a pipeline transport, the flow resistance of pipeline is related closely with the pressure loss and flow. There are important parameters in transportation system design, and directly affect the selection of power equipment and the cost of operation. In view of the uncertain status of flow law for the pipeline transportation of high concentration cemented filling slurry, a pipeline transportation test was con- ducted, and the pipeline transportation features with the filling slurry concentrations of 80% and 81% was studied. The results show that the pressure loss shows cyclic change with the change of time during the pipe pumping process, and the pressure loss increases as the concentration, velocity and frequency increase, Meanwhile, the pressure loss shows a linear growth correlation with the velocity of slurry. Morewove, the flow rate also shows a linear correlation with the slurry velocity, which increases with the velocity increases.

Ding C.,Taiyuan University of Technology | Ai G.,Taiyuan University of Technology | Zhang K.,Shanxi Institute of Coal CAS Chemistry | Yuan Q.,Shanxi Academy of Environmental Research | And 4 more authors.
International Journal of Hydrogen Energy | Year: 2015

Carbon deposition, which may reduce the number of active sites or remove metal particles from the catalyst surface, is an urgent issue for the partial oxidation of methane (POM) to synthesis gas. To solve this problem, Ni/ZrO2@SiO2 catalysts were prepared by a modified Stöber method. The investigation was focused mainly on the role of ZrO2 addition and mesopore silica shell in preventing carbon deposition. The structural properties and carbon deposition of catalysts were characterized by XRD, TEM, N2 adsorption and TG techniques. The oxygen transfer capacity and reducibility of catalysts were evaluated by oxygen storage capacity (OSC) and temperature programmed reduction (TPR). Inspiringly, the Ni/ZrO2@SiO2 catalyst was proved to be more active and possessed less carbon deposition due to the higher reducibility and oxygen storage/release capacity. Importantly, compared with the support catalysts, the catalysts coated by mesopore silica shell showed exceptional resistance to coking, because the edge and corner atoms favor to carbon deposition were selectively blocked by silica shell, in addition, the size of the pore channel prevented growth up of carbon filament. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Ding C.,Taiyuan University of Technology | Gao X.,Taiyuan University of Technology | Han Y.,Shanxi Fenxi Mining Group Co. | Ma X.,Shanxi Fenxi Mining Group Co. | And 4 more authors.
Journal of Energy Chemistry | Year: 2015

In the present work, core-shell Ni@SiO2 catalysts were investigated in order to evaluate the relevance of catalytic activity and surface states of Ni core as well as Ni nanoparticles size to catalytic partial oxidation of methane (POM). The catalysts were characterized by N2 adsorption, H2-TPR, XRD, TEM and XPS techniques. The catalytic performance of the core-shell catalysts was found to be dependent on the surface states of catalyst, which influenced the formation of products. It was considered that carbon dioxide formed on the oxidized nickel sites (NiO) and carbon monoxide produced on the reduced sites (Ni). The surface states of active metal in the dynamic were influenced both by the size of Ni core and the porosity of silica shell. However, the catalytic activity would be debased when the size of Ni core was under a certain extent, which can be ascribed to the fact the carbon deposition increased with the increasing content of NiO. The effects of surface states of Ni@SiO2 catalyst on the catalytic performance were discussed and the reaction pathway over Ni core encapsulated inside silica shell was proposed. © 2015 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences. Published by Elsevier B.V.

Ding C.,Taiyuan University of Technology | Liu W.,Taiyuan University of Technology | Wang J.,Taiyuan University of Technology | Liu P.,CAS Institute of Chemistry | And 6 more authors.
Fuel | Year: 2015

A series of mesoporous NiO-Al2O3 catalysts were prepared by sol-gel method with calcination temperature increasing from 400°C to 800°C. The effect of calcination temperature on the texture property and catalytic performance of NiO-Al2O3 catalysts for partial oxidation of methane (POM) was investigated. These catalysts were evaluated by X-ray diffraction (XRD), transmission electronic microscopy (TEM), N2 adsorption-desorption method and temperature programmed reduction (TPR) techniques and tested in a fixed bed reactor at 550°C. The meso-NiO-Al2O3 catalyst with low carbon deposition prepared at 600°C was proved to be more active, stable. After 40 h reaction at 550°C, the Ni-Al2O3-600 sample still maintained relatively high CH4 conversion and CO yield indicating high activity and stable structure of obtained sample. © 2015 Elsevier Ltd. All rights reserved.

Ren A.,Taiyuan University of Technology | Feng G.-R.,Taiyuan University of Technology | Guo Y.-X.,Taiyuan University of Technology | Qi T.-Y.,Taiyuan University of Technology | And 4 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2014

To study the effects of fly ash on the properties of coal mine filling paste, a slump test and a rheological test were used to evaluate rheological property, and dry shrinkage deformation was measured to study the long term stability and the influence of contact with roof. The rheological property, bleeding index, compressive strength and dry shrinkage were studied with different dosages of fly ash from 64.2% to 69.8% under the condition of invariable mass concentration and the same dosage of cement, coal gangue of filling paste. With the increased dosage of fly ash, the results show that: ① Rheological property abates, adhesiveness enhances, and bleeding index decreases; ② Different curing ages of filling paste has different compressive strength variations: 3 d strength has little variation at about 0.5 MPa. The trend of 7 d strength is initial increase and then drop, the maximum strength is 2.5 MPa at 66.7% dosage of fly ash; 14 d strength is about 4 MPa before 67.8% dosage of fly ash, it reaches 6.9 MPa when at 68.9% dosage of fly ash. The variation of 28 d and 14 d strength are similar. There is a significant hydration from 7 d to 14 d, which can generate from 40% to 60% of 28 d strength of filling paste; ③ The dry shrinkage of filling paste decreases, obeying logarithmic relationship with its age approximately. Dry shrinkage curve of 160 d leveles off, and the dry shrinkage rate is less than 0.2%. ©, 2014, Meitan Xuebao/Journal of the China Coal Society. All right reserved.

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