Hydrodynamics study of a fast liquid–liquid oxidation process with in situ gas production in microreactors

Hydrodynamics characteristics of a fast and highly exothermic liquid–liquid oxidation process with in situ gas production in microreactors were studied using a newly developed experimental method. In the adipic acid synthesis through the K/A oil (the mixture of cyclohexanol and cyclohexanone) oxidation with nitric acid, bubble generation modes were divided into four categories. The gas production became more intensive, unstable, even explosive with increasing the oil phase feed rate and the temperature. A novel automatic image processing method was developed to monitor the instantaneous velocity online by tracking the gas–liquid interface. The axial velocity at the same location was unstable due to the changing gas production rate. Furthermore, the actual residence time was obtained easily with being only 36% of the space–time minimally, beneficial for establishing accurate kinetics and mass transfer models with time participation. Finally, an empirical correlation was developed to predict the actual residence time under different conditions.     

Mixing characteristics for the single and air-water two-phase flows in miniaturized parallel multichannel-based devices

Investigation on the miniaturized parallel multichannel-based devices packed with glass beads to improve the mass exchange execution is the critical focal point of the current study. One of the essential parameters to specify the miniaturized devices' flow distribution is the residence time distribution (RTD). In the present context, the RTDs of a liquid tracer were investigated for the air-water multiphase flows (concurrent) across the multichannel-based miniaturized devices (comprising of 11 similar dimensional parallel channels). The devices were variable in height and packed with glass beads. The conductivity estimations generated the RTD curves and were addressed by the axial dispersion model (ADM). The fluid-flow rates differed within the range of 5–23 ml min⁻¹. The axial dispersion coefficients and the rate of the specific energy dispersion were investigated. The effects of pressure difference and geometry on the hydrodynamic attributes and mixing properties were well-illustrated, and the new correlations were suggested.     

Investigations on Emission Characteristics of a Liquid-Fueled Trapped Vortex Combustor

The combustion and emission formation process of liquid fuel in the trapped vortex combustor(TVC)are very complicated.A trapped vortex combustor with replaceable bluff-bodies was designed to investigate these processes.The bluff-body widths varied from 0.021 m to 0.036 m.Experimental tests were carried out.Liquid RP-3 aviation kerosene was used in the tests.Emissions were measured under atmospheric pressure.The combustion process was analyzed theoretically in the viewpoints of relative evaporation time,mixing time and reaction time.Numerical simulations were also conducted to help analyze the formation and depletion processes of pollutants in TVC.The results reveal that atomization was a critical factor for formation and depletion processes of pollutants.By controlling mixing speed of burned and unburned gases and thus fuel-air uniformity,turbulence intensity could also affect emission levels.In addition,residence time also affected the emissions by affecting combustion completeness and the time for NOx formation.All these factors were combined in a complicated way to affect combustion process and pollutant emissions.     

Liquid yield from juniper and mesquite bio‐fuel gasification

Mesquite (Prosopis glandulosa) and redberry juniper (Juniperus pinchotii) are two woody species which dominate uncultivated lands in the south central Great Plains, USA (Texas, Oklahoma) and may have potential for bioenergy utilization. In this study, these two biomasses were gasified in an adiabatic, updraft fixed‐bed gasifier using air as medium. The products include low heating value gas and liquid tar yield. The effects of fuel moisture content and the equivalence ratio (ER) on liquid yields including heavy tar and light tar and higher heating value (HHV) of the producer gas were investigated. It was found that updraft gasifiers produce a large amount of tar, in a range of 100 g/Nm³ of gas produced. As the equivalence ratio (ER) increased (i.e. more rich char conditions), peak temperature (T_peak) within the bed decreased due to the lesser partial oxidization. The liquid yield showed peak value with change in moisture content between 6 and 24%. Heavy tar is a very high quality fuel with a higher heating value of over 29 MJ/kg on a dry, ash‐free (DAF) basis which is a slightly higher than that of ethanol. Copyright © 2015 John Wiley & Sons, Ltd.     

停留时间对低阶煤快速热解产物分布、组成及结构的影响

利用自由落下床反应器，研究了快速热解过程中颗粒停留时间对神木烟煤和内蒙古褐煤热解过程的影响,并进一步延长快速热解新生半焦停留时间考察了半焦的二次热解过程。结果表明，快速热解过程中颗粒停留时间的增加促进了挥发分的析出，神木烟煤热解焦油产率持续增加，内蒙古褐煤热解焦油产率先增加后降低。停留时间对焦油品质有明显影响，随时间的增加，两种煤快速热解轻质油中苯类和苯酚类单环化合物含量均先增加后降低，进一步延长停留时间，多环芳烃化合物含量显著增加。快速热解半焦的二次热解主要促进了气体的生成，焦油产率和组成无明显变化，挥发分的进一步析出促进了半焦微孔的发展，神木烟煤和内蒙古褐煤半焦比表面积均显著增加。这表明，在以高品质焦油为目标产品时，采用较低的反应温度、较适宜的煤粒停留时间的快速热解工艺条件是可取的。     

基于村落宅图的分类及量化研究——以徽州传统村落群为例

本文以江西省婺源县沱川乡理坑、浙源乡虹关以及思口镇西冲的3次村落测绘作为研究的起点,逐步拓展至对12份徽州传统村落宗族图谱中的村落宅图进行分类及量化研究。通过对村落宅图的研究来还原徽州传统村落群的空间形态,探究其背后的地缘影响、血缘纽带和社会维系,归纳总结出9种村落群的基本构成要素及其所占比率,揭示村落群的空间构成和形态要素。希望在此基础上推演村落群形态的历史演变过程,还原与诠释村落群背后隐藏的内在秩序。     

Mixing of Oil in Water Through Electrical Resistance Tomography and Response Surface Methodology

The mixing performance of the oil‐in‐water dispersion system was evaluated. Using an electrical resistance tomography system composed of two measuring planes, the effect of parameters such as impeller type, impeller speed, oil type, and oil volume fraction on the mixing performance through axial mixing indices were explored. The oil type and the oil volume fraction were identified as the most influential factors on the mixing index. Castor oil, with the highest viscosity of the tested oils, was found as the most difficult oil to disperse. The Scaba impeller was the most efficient impeller in dispersing oil in water. The interactions between oil type and impeller type as well as between impeller speed and oil type, had the greatest impact on the mixing index.     

Ultrasonic Fabrication of Polymer Plate Reactors with a Surface Coating

Microreactors offer several advantages compared to the industrial scale when developing new chemical processes. Especially the production and investment costs are low if polymer microreactors are generated by ultrasonic processes. In order to observe the chemical reaction and the flow configuration, these microreactors need to be optically transparent, mechanically stable, and chemically inert to several reagents. The manufacturing process of a transparent polymer plate reactor with a chemically inert surface coating by ultrasonic fabrication is described. Experimental characterization of the microreactors showed that they are leak tight up to a pressure difference of at least 300 kPa and the mixing times are in the range of milliseconds.     

Structural Characteristics and Contemporary Value of Traditional Water Cultural Landscapes in Huizhou Region

Water culture is one of the key issues in Water Ecological Civilization. China’s traditional water cultural landscape embodies rich water cultures, and have a significance in related research and protection practice. This paper proposes the concept of “water cultural landscape,” that is, the landscape formed through humans’ environmental alteration during water activities—including how people use, transform, and manage it. The traditional water cultural landscapes in Huizhou Region have developed over hundreds of years, reflecting the locals’ wisdom in sustainable water use. The water cultural landscape in Huizhou Region should be interpreted as a systematic notion, in which all landscape elements such as ponds, weirs, and shuikous are interdependent, composing the landscape components e.g. valleys, hills, and basins, and establishing water security patterns for cities, towns, villages, and for production. The traditional water cultural landscape in Huizhou Region requires local generations’ long-term maintenance and management, and in turn it is also vital to Huizhou people's life and Huizhou culture. Today, it acts as an ecological infrastructure for sponge countryside and sponge city construction, and an important resource for heritage protection and tourism development.