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241.
大力发展氢能是实现“碳达峰、碳中和”目标的重要途径之一。将氢气掺入现有天然气管网利于实现氢能经济高效、大规模输送与应用。安全掺氢比是掺氢天然气管输系统有待解决的关键问题之一。有观点提出当掺氢天然气中的掺氢比在10%以下时,可无需加以验证地直接通过天然气管网输送。本文提出从目前来看,该观点不成立。文章从管网系统掺氢适应性、示范项目掺氢比探讨和标准规范3个方面阐述了个中缘由。文中指出,掺氢天然气管输技术正处于起步阶段,其安全保障还面临诸多挑战,任何结论都需要经过反复论证和验证,以稳步推动氢能产业发展。 相似文献
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Effect of mixer geometry and operating conditions on flow mixing of shear thinning fluids with yield stress 下载免费PDF全文
Jaime Sossa‐Echeverria Fariborz Taghipour 《American Institute of Chemical Engineers》2014,60(3):1156-1167
Flow mixing of a non‐Newtonian fluid in a stirred tank equipped with a side‐entry impeller was observed using particle image velocimetry (PIV). The effects of some geometrical parameters including the mixer shape and impeller type and position on the flow pattern were studied on velocity fields obtained at different locations inside the mixing domain. The different flow structures revealed that the ratio of inertial and viscous forces largely defines the flow pattern. Dead zones were observed inside the tank due to the rheological properties of the fluid. The size of the dynamic regions and the average velocity near the impeller were enhanced by increasing the suction area. Likewise, large pitch ratios were found to improve the active mixing zone and the axial discharge. Curves for the power and pumping numbers are reported for different axial flow impellers. © 2013 American Institute of Chemical Engineers AIChE J, 60: 1156–1167, 2014 相似文献
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Distribution of large biomass particles in a sand‐biomass fluidized bed: Experiments and modeling 下载免费PDF全文
Farzam Fotovat Jamal Chaouki Jeffrey Bergthorson 《American Institute of Chemical Engineers》2014,60(3):869-880
The axial distribution of large biomass particles in bubbling fluidized beds comprised of sand and biomass is investigated in this study. The global and local pressure drop profiles are analyzed in mixtures fluidized at superficial gas velocities ranging from 0.2 to 1 m/s. In addition, the radioactive particle tracking technique is used to track the trajectory of a tracer mimicking the behavior of biomass particles in systems consisting of 2, 8, and 16% of biomass mass ratio. The effects of superficial gas velocity and the mixture composition on the mixing/segregation of the bed components are explored by analyzing the circulatory motion of the active tracer. Contrary to low fluidization velocity (U = 0.36 m/s), biomass circulation and distribution are enhanced at U = 0.64 m/s with increasing the load of biomass particles. The axial profile of volume fraction of biomass along the bed is modeled on the basis of the experimental findings. © 2014 American Institute of Chemical Engineers AIChE J, 60: 869–880, 2014 相似文献
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Mixing potential: A new concept for optimal design of hydrogen and water networks with higher disturbance resistance 下载免费PDF全文
Zuwei liao Junyi Lou Jingdai Wang Binbo Jiang Yongrong Yang 《American Institute of Chemical Engineers》2014,60(11):3762-3772
During the last decade, the design methods of hydrogen and water networks have been improved greatly. Since the resulting network structure featuring minimum utility consumption is not unique, other properties such as disturbance resistance have drawn more and more attention. In this article, a novel concept, Mixing Potential, is proposed to improve the disturbance resistance ability of the networks in the design stage. This concept originates from measuring the concentration fluctuation of a single sink, and could be calculated by its graphical and algorithmic definition, respectively. In addition, a sufficient condition for minimizing the Mixing Potential of a single sink has been proved. Based on this sufficient condition, a graphical and its corresponding algorithmic method are proposed to design the hydrogen and water networks with minimum utility consumption. Literature examples illustrate that the disturbance resistance ability of the network can be improved by adjusting the satisfying order of sinks. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3762–3772, 2014 相似文献
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Wojciech Turalski Andrzej Miniewicz Stanislaw Bartkiewicz 《Advanced functional materials》1996,6(1):15-25
Dynamic self-diffraction processes have been observed and analysed for methylene blue-sensitised water-swollen gelatine (MBSG). A degenerate two-wave mixing experiment performed on thick samples of MBSG with 10 mW, 632.8 nm wavelength He Ne laser light allowed for the formation of phase- and amplitude-transient holographic gratings. Single-beam propagation characteristics through MBSG were measured with a Mach-Zehnder interferometer. The observed energy transfer between the writing beams in the two-beam coupling experiment and the considerable temporal oscillations of diffraction efficiency are explained by simple formulae. Two processes are considered: the time-dependent phase shift between the writing beams and the transverse self-phase modulation effects (self-focusing and interference ring formation). 相似文献