In this study,low-rank coal-water slurry(LCWS)was prepared using polyoxyethylene dodecylphenol ether(PDPE)and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to inv...In this study,low-rank coal-water slurry(LCWS)was prepared using polyoxyethylene dodecylphenol ether(PDPE)and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to investigate the pulping properties and microscopic mechanism of the LCWS samples prepared using the two agents,so as to explore the influence of benzene ring on the performance of dispersant.The results of the LCWS preparation experiments revealed that the pulp-forming performance of PDPE exceeded that of PLE.When LCWS concentration is 62%,64%,and 66%,the apparent viscosity corresponding to PDPE is 247.80,504.17,and 653.10 mPa·s,and the apparent viscosity corresponding to PLE is 548.10,1470.61,and 1549.98 mPa·s,respectively.The C_(1000)(When the apparent viscosity is 1000 mPa·s,the corresponding concentration of LCWS is defined as C_(1000))values of PDPE and PLE are 67.60%and 62.95%,respectively.In addition to the van der Waals forces and hydrogen bonds between the PDPE and/or PLE molecules and coal,the benzene rings of PDPE presentπ-πstacking effect with the aromatic rings of coal.That could facilitate and strengthen the adsorption of PDPE on coal,which would be conducive to further improving the dispersion of coal particles.The two dispersants have no significant difference in effect on the pyrolysis of LCWS.The simulation results indicated that the times for PDPE and PLE molecules to reach flat adsorption state on coal are approximately 290 and 565 ps,respectively.The self-diffusion coefficient(D)of the PDPE and PLE on coal is 3.16 x 10^(-6)and6.57×10^(-6)m~2/s,respectively,and their interaction energies with coal are 785.71 and 648.60 kcal/mol,respectively.The results of the simulation calculations demonstrated that PDPE adsorbed on coal easier than PLE,and its binding is more stable than that of PLE owing to theπ-πstacking effect,which is conducive to uniform dispersion of coal in solution.The simulation results confirmed the experimental results.展开更多
Wastewater from the thermochemical conversion of coal and biomass contains a significant amount of phenolic structures compounds.The degradation of these phenolic compounds to hydrogen-rich gasses can prevent envi-ron...Wastewater from the thermochemical conversion of coal and biomass contains a significant amount of phenolic structures compounds.The degradation of these phenolic compounds to hydrogen-rich gasses can prevent envi-ronmental pollution and save energy.Supercritical water(SCW)gasification of phenol is experimentally studied and a reactive force field molecular dynamics(ReaxFF-MD)simulation is conducted to investigate the catalytic mechanism of Ni/Al2 O3 in the phenol degradation.The experimental results indicate that Ni/Al2 O3 facilitates the conversion of phenol to 1-ethoxy butane via ring opening,which is a crucial step for complete gasification.The ReaxFF-MD simulation demonstrated that Ni facilitates the formation of H3 O free radicals and Ni-phenol inter-mediates.H3 O free radicals can be decomposed into H2 and OH free radicals.Both the generated OH free radical and Ni-phenol intermediate promote the ring-opening reaction of phenol.Ni promotes the direct decomposition of phenol into C1,C2,and C3 fragments,which is beneficial for further complete gasification.展开更多
Transportation of heavy oil by the so-called water-ring technique is a very promising method by which pressure drop and pollution can be significantly reduced.Dedicated experiments have been carried out by changing th...Transportation of heavy oil by the so-called water-ring technique is a very promising method by which pressure drop and pollution can be significantly reduced.Dedicated experiments have been carried out by changing the phase’s density,viscosity,velocity and interfacial tension to systematically analyze the characteristics of the water ring.On the basis of such experimental data,a mathematical model for pressure drop prediction has been introduced.This research shows that as long as the density of oil and water remains the same,a concentric water ring can effectively be formed.In such conditions,the oil-water viscosity difference has little effect on the shape of water ring,and it only affects the pressure drop.The greater the viscosity of heavy oil,the smaller the pressure drop of the oil-water ring transportation system.The influence of phases’interfacial tension on the characteristics and pressure drop of the heavy oil-water ring can be considered negligible.The pressure drop prediction model introduced on the basis of the Buckingham’s principle provides values in good agreement(95%)with the experimental data.展开更多
The propagation of ring wave packet (composed of carrier waves modulated by an envelope) generated by a water drop was studied experimentally. It is a localized wave packet propagating with constant velocity and low d...The propagation of ring wave packet (composed of carrier waves modulated by an envelope) generated by a water drop was studied experimentally. It is a localized wave packet propagating with constant velocity and low diffusion. The wavelength, the amplitude and the waveform of the carrier waves, the velocity of the carrier waves and the packet have been measured. The measured wavelength λe of the carrier waves and the measured group velocity Cge of the packet are near the minimum point of the dispersion curve of group velocity, which may be the main reason why the packet can propagate with low diffusion.展开更多
基金supported by National Natural Science Foundation of China(Nos.51904174 and 52074175)Postdoctoral Science Foundation of China(No.2019M662403)+3 种基金Young Science and Technology Innovation Program of Shandong Province(No.2020KJD001)Key Research and Development Project of Shandong(No.2019GGX103035)SDUST Research Fund(No.2018TDJH101)Project of Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team。
文摘In this study,low-rank coal-water slurry(LCWS)was prepared using polyoxyethylene dodecylphenol ether(PDPE)and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to investigate the pulping properties and microscopic mechanism of the LCWS samples prepared using the two agents,so as to explore the influence of benzene ring on the performance of dispersant.The results of the LCWS preparation experiments revealed that the pulp-forming performance of PDPE exceeded that of PLE.When LCWS concentration is 62%,64%,and 66%,the apparent viscosity corresponding to PDPE is 247.80,504.17,and 653.10 mPa·s,and the apparent viscosity corresponding to PLE is 548.10,1470.61,and 1549.98 mPa·s,respectively.The C_(1000)(When the apparent viscosity is 1000 mPa·s,the corresponding concentration of LCWS is defined as C_(1000))values of PDPE and PLE are 67.60%and 62.95%,respectively.In addition to the van der Waals forces and hydrogen bonds between the PDPE and/or PLE molecules and coal,the benzene rings of PDPE presentπ-πstacking effect with the aromatic rings of coal.That could facilitate and strengthen the adsorption of PDPE on coal,which would be conducive to further improving the dispersion of coal particles.The two dispersants have no significant difference in effect on the pyrolysis of LCWS.The simulation results indicated that the times for PDPE and PLE molecules to reach flat adsorption state on coal are approximately 290 and 565 ps,respectively.The self-diffusion coefficient(D)of the PDPE and PLE on coal is 3.16 x 10^(-6)and6.57×10^(-6)m~2/s,respectively,and their interaction energies with coal are 785.71 and 648.60 kcal/mol,respectively.The results of the simulation calculations demonstrated that PDPE adsorbed on coal easier than PLE,and its binding is more stable than that of PLE owing to theπ-πstacking effect,which is conducive to uniform dispersion of coal in solution.The simulation results confirmed the experimental results.
文摘为了研究水泵水轮机在调相工况下转速对水环流动的影响,应用ANSYS CFX软件对某中比转数水泵水轮机在调相工况下的水环流动特性进行全流道非定常数值计算,分析水泵水轮机在不同转速下(n=600,800,1000,1050 r/min)水环的压力脉动特性和流动特性.研究结果表明:无叶区水环的厚度与转速密切相关,转速越大,水环内自由液面的平均半径越大,水环厚度越薄;不同转速下无叶区内的压力脉动频率组成成分相同,主频均为由动静干涉作用引起的7 f n,且随着转速的增大主频的幅值增大,水环的流动速度增大;在相同转速下,无叶区周向压力脉动强度变化不明显,但在无叶区径向,越靠近转轮处压力脉动越小;转轮出口处有明显的气液分界面,整个转轮流道内充满气体,这表明水环对气体密封的效果良好.研究结果可为水泵水轮机调相工况运行提供一定参考.
基金supported by the National Natural Science Founda-tion of China(Grant Nos.:51976046 and 52006044)the Shenzhen Technology Project(Grant No.:RCJC20210609103755110).
文摘Wastewater from the thermochemical conversion of coal and biomass contains a significant amount of phenolic structures compounds.The degradation of these phenolic compounds to hydrogen-rich gasses can prevent envi-ronmental pollution and save energy.Supercritical water(SCW)gasification of phenol is experimentally studied and a reactive force field molecular dynamics(ReaxFF-MD)simulation is conducted to investigate the catalytic mechanism of Ni/Al2 O3 in the phenol degradation.The experimental results indicate that Ni/Al2 O3 facilitates the conversion of phenol to 1-ethoxy butane via ring opening,which is a crucial step for complete gasification.The ReaxFF-MD simulation demonstrated that Ni facilitates the formation of H3 O free radicals and Ni-phenol inter-mediates.H3 O free radicals can be decomposed into H2 and OH free radicals.Both the generated OH free radical and Ni-phenol intermediate promote the ring-opening reaction of phenol.Ni promotes the direct decomposition of phenol into C1,C2,and C3 fragments,which is beneficial for further complete gasification.
基金Foundation Projects:Major National R&D Project(2016ZX05025-004-005).
文摘Transportation of heavy oil by the so-called water-ring technique is a very promising method by which pressure drop and pollution can be significantly reduced.Dedicated experiments have been carried out by changing the phase’s density,viscosity,velocity and interfacial tension to systematically analyze the characteristics of the water ring.On the basis of such experimental data,a mathematical model for pressure drop prediction has been introduced.This research shows that as long as the density of oil and water remains the same,a concentric water ring can effectively be formed.In such conditions,the oil-water viscosity difference has little effect on the shape of water ring,and it only affects the pressure drop.The greater the viscosity of heavy oil,the smaller the pressure drop of the oil-water ring transportation system.The influence of phases’interfacial tension on the characteristics and pressure drop of the heavy oil-water ring can be considered negligible.The pressure drop prediction model introduced on the basis of the Buckingham’s principle provides values in good agreement(95%)with the experimental data.
基金the State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciencespartially supported by the National Natural Science Foun-dation of China (Grant No. 10674081)
文摘The propagation of ring wave packet (composed of carrier waves modulated by an envelope) generated by a water drop was studied experimentally. It is a localized wave packet propagating with constant velocity and low diffusion. The wavelength, the amplitude and the waveform of the carrier waves, the velocity of the carrier waves and the packet have been measured. The measured wavelength λe of the carrier waves and the measured group velocity Cge of the packet are near the minimum point of the dispersion curve of group velocity, which may be the main reason why the packet can propagate with low diffusion.
