低压天然气轻烃回收工艺

通过对现有低压天然气(0.3～1.6MPa)轻烃回收方法比较, 提出一种新的改进吸附回收工艺, 降低生产消耗, 提高轻烃的收率。本工艺采用两段变温变压吸附(T-PSA)方法相结合, 第一段T-PSA主要脱除原料气中水分, 第二段T-PSA主要回收原料气中的轻烃, 回收的轻烃以压力不低于1.6MPa的液相混烃作为产品, 保证烃露点要求, 满足储运安全。本工艺具有较高的轻烃收率, 丙烷和丁烷收率均大于94%, 较目前常采用的深冷回收方法和一段变温吸附法的轻烃收率提高了30%～40%, 带来明显的经济效益, 同时本工艺较外冷回收方法, 操作弹性更大, 适用性更强, 特别适合小规模生产或需要经常搬迁的生产环境。因此, 改进吸附回收工艺非常值得推广应用。     

Ammonia synthesis enhanced by magnesium chloride absorption

Conversion to ammonia with Haber–Bosch catalysts can be increased above 95% by selective absorption of ammonia by MgCl₂. The maximum conversion depends on reaction and absorption equilibria. At very short times, the measured conversion rate is the same with and without absorption by the MgCl₂ salt; the overall rate constants are comparable to those in the literature. At larger times, conversion to ammonia can be over seven times greater with MgCl₂ than without. However, the overall rate constants can be over 10 times slower because they are controlled by ammonia diffusion in the solid salt. An approximate, pseudosteady state theory consistent with these results provides a strategy for improving the overall rate while keeping the conversion over 90%. For example, the absorption rates might be increased using smaller particles of absorbent on a porous inert absorbent support. The results provide part of the basis for designing small scale ammonia plants. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1364–1371, 2015     

Fabrication of a low‐cost nano‐SiO2/PVC composite ultrafiltration membrane and its antifouling performance

A novel low‐cost SiO₂/Polyvinylchloride (PVC) membrane with different nano‐SiO₂ particles loading (0–4 wt %) was prepared by the phase‐inversion process. The optimum nano‐SiO₂ dosage was determined as 1.5 wt % based on the casting solution compositions, the membranes' mechanical properties and hydrophilicities, the pure water fluxes, microstructures, and absorption of protein. Compared with the bare membrane, the membrane with 1.5 wt % nano‐SiO₂ addition presented better capabilities against the protein absorption and bacterial attachment, better antifouling performance, and higher flux recovery ratio in filtration of the supernatant liquor which collected from a secondary sedimentation tank in a municipal wastewater plant. The SiO₂/PVC membranes have applicable potential in the municipal wastewater treatment for their low price, good antifouling performance and high removal efficiencies of SS (over 97.2%), COD (up to 82.9%) and total bacteria (more than 93.6%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41267.     

室温下ZnO超疏水表面的制备及油水分离性能

利用简便的液相法,在室温下于不锈钢网上沉积ZnO纳米片和纳米花粗糙结构,接着通过浸渍法修饰低表面能物质硬脂酸,制备了超疏水不锈钢网。对沉积后的不锈钢网表面形貌、晶体结构、润湿性能、耐磨性能、油水分离性能等进行表征与测定。结果表明,该不锈钢网表面由纳米片和纳米花组成的微纳米结构ZnO构成,具有超疏水性,水接触角161 °;油水分离效率达98%,循环使用20次后分离效率仍保持在95.5%以上;具有良好的机械耐磨性,在高盐环境中表现出化学稳定性。     

来瓦希尔骨架材料MIL-53(Al)填充PEBA膜渗透汽化分离水中苯胺

将来瓦希尔骨架材料MIL-53(Al)引入到聚醚共聚酰胺（PEBA-2533）高分子相中制备了不同填充量的PEBA/MIL-53(Al)杂化膜并用于渗透汽化分离水中微量苯胺。X-射线衍射结果证实MIL-53(Al)被成功合成。扫描电镜和激光粒度分析结果表明所制备MIL-53(Al)颗粒粒径在纳米尺度范围内。采用扫描电镜、红外光谱、X-射线衍射、差示扫描量热和水接触角对杂化膜进行了表征,并考察了杂化膜的溶胀行为和分离性能。结果表明,所得杂化膜的热稳定性较好。当MIL-53(Al)质量分数小于20%时,MIL-53(Al)在高分子相中分散均匀,继续增大填充量出现团聚现象。杂化膜的结晶度随MIL-53(Al)填充量的增加而降低。MIL-53(Al)的引入增强了杂化膜的疏水性和溶胀度。在料液温度为60℃、膜下游压力400Pa、料液苯胺质量分数为3.6%时,MIL-53(Al)质量分数为20%的杂化膜（M-20）综合分离性能最优,渗透通量达到2.15kg/(m²·h),分离因子为264。12天的稳定性测试结果表明所得杂化膜分离性能无显著变化,能够满足渗透汽化应用要求。     

Inverted organic photovoltaic device with a new electron transport layer

We demonstrate that there is a new solution-processed electron transport layer, lithium-doped zinc oxide (LZO), with high-performance inverted organic photovoltaic device. The device exhibits a fill factor of 68.58%, an open circuit voltage of 0.86 V, a short-circuit current density of −9.35 cm/mA² along with 5.49% power conversion efficiency. In addition, we studied the performance of blend ratio dependence on inverted organic photovoltaics. Our device also demonstrates a long stability shelf life over 4 weeks in air.     

Research progress on electronic phase separation in low-dimensional perovskite manganite nanostructures

Perovskite oxide manganites with a general formula of R_1-x AxMnO₃ (where R is a trivalent rare-earth element such as La, Pr, Sm, and A is a divalent alkaline-earth element such as Ca, Sr, and Ba) have received much attention due to their unusual electron-transport and magnetic properties, which are indispensable for applications in microelectronic, magnetic, and spintronic devices. Recent advances in the science and technology have resulted in the feature sizes of microelectronic devices based on perovskite manganite oxides down-scaling into nanoscale dimensions. At the nanoscale, low-dimensional perovskite manganite oxide nanostructures display novel physical properties that are different from their bulk and film counterparts. Recently, there is strong experimental evidence to indicate that the low-dimensional perovskite manganite oxide nanostructures are electronically inhomogeneous, consisting of different spatial regions with different electronic orders, a phenomenon that is named as electronic phase separation (EPS). As the geometry sizes of the low-dimensional manganite nanostructures are reduced to the characteristic EPS length scale (typically several tens of nanometers in manganites), the EPS is expected to be strongly modulated, leading to quite dramatic changes in functionality and more emergent phenomena. Therefore, reduced dimensionality opens a door to the new functionalities in perovskite manganite oxides and offers a way to gain new insight into the nature of EPS. During the past few years, much progress has been made in understanding the physical nature of the EPS in low-dimensional perovskite manganite nanostructures both from experimentalists and theorists, which have a profound impact on the oxide nanoelectronics. This nanoreview covers the research progresses of the EPS in low-dimensional perovskite manganite nanostructures such as nanoparticles, nanowires/nanotubes, and nanostructured films and/or patterns. The possible physical origins of the EPS are also discussed from the signatures of electronic inhomogeneities as well as some theoretical scenarios, to shed light on understanding this phenomenon. Finally, the perspectives to the future researches in this area are also outlined.     

Tailoring the grooved texture of electrospun polystyrene nanofibers by controlling the solvent system and relative humidity

In this study, we have successfully fabricated electrospun polystyrene (PS) nanofibers having a diameter of 326 ± 50 nm with a parallel grooved texture using a mixed solvent of tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). We discovered that solvent system, solution concentration, and relative humidity were the three key factors to the formation of grooved texture and the diameter of nanofibers. We demonstrated that grooved nanofibers with desired properties (e.g., different numbers of grooves, widths between two adjacent grooves, and depths of grooves) could be electrospun under certain conditions. When THF/DMF ratio was higher than 2:1, the formation mechanism of single grooved texture should be attributed to the formation of voids on the jet surface at the early stage of electrospinning and subsequent elongation and solidification of the voids into a line surface structure. When THF/DMF ratio was 1:1, the formation mechanism of grooved texture should be ascribed to the formation of wrinkled surface on the jet surface at the early stage of electrospinning and subsequent elongation into a grooved texture. Such findings can serve as guidelines for the preparation of grooved nanofibers with desired secondary morphology.     

Rapid and large‐scale separation of magnetic nanoparticles by low‐field permanent magnet with gas assistance

Bubbles can be used to greatly improve the speed of magnetic separation (MS) and overcome the limitation of magnetic force on the capture distance, making low‐field MS highly efficient and easily scalable. This novel method leads to the development of a medium‐free continuous gas‐assisted magnetic separator on small pilot scale using low‐field permanent magnet. This separator is demonstrated highly efficient for recovery of proteins‐loaded magnetic nanoparticles from large volume biosuspension. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3101–3106, 2014     

A lattice Boltzmann simulation of mass transport through composite membranes

Composite membranes with a porous support layer and a dense skin layer have been extensively used in gas separation processes. A new approach, a mesoscale Lattice Boltzmann Simulation approach, is proposed and used to model the pore‐scale gas flow and mass transfer in the inhomogeneous membrane matrixes studied. Only physical forces are considered. Chemical forces are equivalently converted to physical forces through the relaxation time. Selective permeation of moisture through a composite membrane is modeled. The overall permeability is evaluated. It is found that mass transfer inhomogeneity exists not only in the porous media but also in the seemingly uniform dense skin layer. Increasing the diffusivity in the skin layer is more effective than decreasing the skin layer thickness in optimizing the overall membrane performance. The new approach gives more detailed insights into the directions for future design of composite membranes for gas separations like air dehumidification. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3925–3938, 2014