In-line mixing for high reactive species using swirl flow ejector

The use of in-line static mixers has been widely advocated for an important variety of applications, such as continuous mixing, heat and mass transfer processes, and chemical reactions. This paper extends previous studies by the authors on industrial static mixers and illustrates how static mixing processes of single-phase viscous liquids can be numerically simulated. Mixing of Newtonian, shear-thinning, and shear-thickening fluids through static mixer, as well as thermal enhancement by static mixer is studied. Using different measuring tools, the global performance and costs of SMX (Sulzer mixer X) and helical static mixers are studied. It is shown that the SMX mixer manifests a higher performance; however, the required energy to maintain the flow across a SMX mixer is significantly higher.

Effects of internal geometry modifications on the dispersive and distributive mixing in static mixers

BACKGROUNDTubular photobioreactors are considered to be important and potential photobioreactors due to their higher photosynthetic efficiency and biomass productivity. In this work the performance of a new tubular photobioreactor with novel static mixers on mixing characteristics and light regime was studied through computational fluid dynamics.RESULTSThe effects of cross‐angle of two blades, horizontal spacing, open porosity and hole radius of the novel static mixers on mixing characteristics were investigated to obtain appropriate configurations. Compared with the tubular photobioreactor without static mixers, the tubular photobioreactor with novel static mixers was proved to have strong fluid mixing and significant swirling flow. Average velocity magnitude along the light direction increased by nearly 1000 times and turbulent kinetic energy increased by 1.3 times after adding novel static mixers into the tubular photobioreactor. Additionally, with novel static mixers most cells were promoted to circulate between the light zone and the dark zone. The light/dark cycle frequency was also improved and increased by 85.21% and 95.77% at fluid inlet velocity of 0.3 and 0.4 m s−1, respectively.CONCLUSIONThe simulation results showed the novel static mixers could effectively enhance mixing degree of fluid and increase the light/dark cycle frequency of microalgal cells in tubular photobioreactors. © 2014 Society of Chemical Industry

This review focuses on rapid mixing in the coagulation process for improved natural organic matter (NOM) removal in water treatment.Rapid mixing aims to instantly and efficiently disperse coagulant species into raw water, before flocculation, sedimentation, and filtration processes.Mechanical mixing with a longer retention time cannot guarantee an instantaneous and uniform coagulant dispersion.For this reason, the so-called pump diffusion mixer (PDM) has been proposed.Using various rapid mixing devices to test the sedimentation performance, it is showed that in-line hydraulic jet and static mixers are able to achieve performance equivalent to that of the mechanical mixing type at a lower coagulant dosage.On the other hand, the removal of NOM as disinfection by-products (DBPs) precursor by chemical coagulation (CC) has been extensively studied.It is well reported that enhanced coagulation (EC) by adjusting the pH downwards to 4-5 prior to coagulant addition will encourage the formation of soluble NOM-Al complex from low-turbidity waters.In case of most waters, therefore, acid must be added to maintain the desired coagulation pH for EC, and excess coagulant is required to improve the removal of NOM.However, CC using in-line hydraulic jet mixer such as PDM is a reasonable method for the improvement of coagulation process compared to EC, since it is possible to obtain good removals of NOM as well as turbidity using a lower dosages of coagulant without supplementary addition of chemicals for pH control and thus producing a smaller volume of waste solids.

Evaluation of continuously mixed reactor configurations in the oxidative-adsorptive desulfurization of diesel fuel: Optimization and parametric studies

Streamlining regular liquid chromatography with MALDI-TOF MS and NMR spectroscopy using automatic full-contact splitless spotting interface and flash-tap fractioning collection

The cold gas dynamic spraying process provides an advantageous solution to the deposition, and additive manufacturing, of metals. Namely, it provides a reduced reactive environment, simple operation, and high deposition rates. It is known that the deposition efficiency of the cold spray process can be substantially increased using helium instead of nitrogen as the process gas. However, the use of pure helium can be cost prohibitive and commercially available helium recovery systems constitute a major capital investment and cannot be used with portable systems. This work focuses on the development and use of a novel, in-line gas mixing system, designed to provide a blend of nitrogen and helium at any ratio. Deposits produced with different gas ratios are investigated through particle velocity measurements, deposition efficiency, coating porosity, and coating hardness. The experimental results show that helium, even in lower percentages, can have a significant effect on deposition efficiency and coating quality. From the results, a cost model is presented which, when provided experimental values and user costs, can be used to identify the nitrogen–helium ratio that will produce the lowest overall coating cost.

On the mixing enhancement in concentrated non-colloidal neutrally buoyant suspensions of rigid particles using helical coiled and chaotic twisted pipes: A numerical investigation

The flow and mixing behavior in structures used in static mixers and structured packings are visualized. Results show, that the geometrical parameters of these structures significantly affect the mixing behavior of the flow within these structures. By proper choice of the parameters compact mixers with a homogeneous mixing behavior can be achieved.

Bench and full-scale studies for odor control from lime stabilized biosolids: The effect of mixing on odor generation

Micromixing efficiency in static mixer

To increase service coverage and meet the increasing demand for drinking water, PDAM Tirta Kahuripan plans to build a Ciawi WTP in Megamendung District with a processing capacity of 165 L/second using the Sukabirus River as a raw water source. The purpose of this study was to determine the processing units in the design of the Ciawi WTP using multi-criteria analysis. Based on the results of the analysis of raw water quality, there were several parameters that do not meet the drinking water quality standards according to the Minister of Health Regulation No. 492 of 2010 and PPRI No. 82 of 2001, namely turbidity, Fecal coliform, total coliform, TSS, BOD, COD, and DO. There were three alternative processing circuits used. Alternative I consists of intake, hydraulic coagulation, up-down flow hydraulic flocculation, plate settler sedimentation, rapid sand filtration, disinfection, and reservoir. Alternative II consists of intake, hydraulic coagulation, vertical-shaft paddle wheel mechanical flocculation, tube settler sedimentation, rapid sand filtration, disinfection, and reservoir. Alternative III consists of intake, in-line static mixers coagulation, horizontal-shaft paddle wheel mechanical flocculation, plate settler sedimentation, rapid sand filtration, disinfection, and reservoir. There are other factors that must be considered in the selection of treatment units, namely contaminant removal, reliability, flexibility, construction, land requirements, ease of operation, maintenance, cost, and environmental compatibility. Based on multi-criteria analysis, the percentage of suitability for alternative I is 78%, Alternative II is 63%, and Alternative III is 48%. From this assessment, it can be said that alternative I is the best alternative.

CFD simulation of swirling flow induced by twist vanes in a rod bundle

A novel Static Mixer for photochemical reactions

Transcriptional targeting to brain cells: Engineering cell type-specific promoter containing cassettes for enhanced transgene expression