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NO gas emission has harmfully impacted human health and the environment. Absorption of NO gas into an aqueous solution is considered to be a promising approach for its removal. FeII(EDTA) solution has been demonstrated as an efficient option in the denitrification process. However, its absorption rate is strongly affected by mass transfer limitation of NO into FeII(EDTA) solution in traditional reactors. In this paper, the removal process of NO with FeII(EDTA) solution was studied in a microporous tube-in-tube microchannel reactor (MTMCR). The effects of design and operating parameters such as micropore size, annular channel width, liquid flow rate, gas flow rate, gas-liquid ratio, pH and concentration of absorbent, and absorption temperature on overall volumetric mass transfer coefficient ( KLa) and NO removal efficiency were explored. The results indicated that the MTMCR exhibited obvious advantages owing to continuous operation mode and higher NO removal efficiency of over 90 %, as compared to traditional reactors. Both KLa and NO removal efficiency increased with increases of absorbent concentration and liquid flow rate, as well as decreases of absorption temperature, micropore size, and annular channel width. In addition, KLa increased while NO removal efficiency decreased with increasing gas-liquid ratio and gas flow rate. The obtained results imply a great potential of the MTMCR in the removal of NO from post-combustion flue gas. [ABSTRACT FROM AUTHOR]

In this article, preliminary experimental results are presented on the absorption of carbon dioxide (CO2) in a novel high-throughput microporous tube-in-tube microchannel reactor (MTMCR), with an aqueous solution of monoethanolamine (MEA) and a mixture of CO2/N2as the working fluids. The effects of design and operating parameters on the CO2removal efficiency were investigated. The absorbent concentration was given the priority as a key factor for consideration, with the result that the CO2removal efficiency increased with increasing concentrationan and could reach 90% or even higher at a high throughput of 440 L/h for gas with an MEA concentration of 30 wt %. With a decrease of the superficial gas velocity or an increase of the superficial liquid velocity, the CO2removal efficiency increased. Increasing the absorbent temperature yielded better absorption performance. Reducing the most important structural parameters of the MTMCR, such as the micropore size and the annular channel width, led to a higher mass-transfer rate and was beneficial for CO2removal. This work also investigated the characteristics of the pressure drop of two-phase flows through the MTMCR. The results obtained imply a great potential for MTMCRs applied to the separation of the greenhouse gas CO2from the exhausted gases. [ABSTRACT FROM AUTHOR]

Abstract: In this work, size-controllable nanoparticles of amorphous cefuroxime axetil (CFA), a poorly water-soluble drug, have been prepared in a Y-junction microchannel reactor (YMCR) by nanoprecipitation for enhancing dissolution rate of CFA. The effects of the operation parameters, such as flow rate of CFA acetone solution, antisolvent flow rate, overall flow rate, CFA concentration and precipitation temperature, on particle size and size distribution were experimentally investigated. The results indicated that the particle size obviously decreased from 1100 to 630nm with decreasing the CFA solution flow rate from 16 to 2mL/min, and decreased from 450 to 350nm with the decreased temperature from 50 to 5°C. However, with the increase of the antisolvent flow rate at a fixed CFA solution flow rate of 4mL/min, the particle size obviously decreased from 1229nm (20mL/min) to 581nm (60mL/min), and then increased to 698nm (80mL/min). Also, the particle size firstly decreased and then increased with the increase of the overall flow rate and CFA solution concentration. The as-prepared CFA nanoparticles displayed a size-dependent and significantly enhanced dissolution property when compared to raw CFA and commercial spray-dried CFA. This work suggests that the continuous synthesis in a microfluidic reactor is a simple and economic way to prepare pharmaceutical nanoparticles with tunable sizes. [ABSTRACT FROM AUTHOR]

Abstract: This article presents the preparation of nanoparticles of amorphous cefuroxime axetil (CFA) in a microporous tube-in-tube microchannel reactor (MTMCR). The experimental results indicated that CFA particle with a tunable size of 400–1400nm could be achieved under a high throughput in the range of 1.5–6L/min. The average particle size decreased with increasing overall volumetric flow rate and decreasing CFA concentration, micropore size, and annular channel width. The produced CFA nanoparticles were characterized by SEM, XRD, FT-IR, DSC and a dissolution test, which indicated that the nanosized CFA was amorphous and exhibited higher dissolution rate compared to the raw CFA. The MTMCR might offer a general and facile pathway for mass production of the nanoparticles of hydrophobic pharmaceuticals thanks to its high throughput capacity and excellent micromixing performance. [Copyright &y& Elsevier]

Abstract: One method for increasing productivity of a microreactor is presented without demanding numbering-up processes by using a newly proposed microporous tube-in-tube microchannel reactor (MTMCR) with a high throughput of 9L/min. Barium sulphate nanoparticles with an average size of 37nm and a narrow size distribution were successfully produced in MTMCR. The size of barium sulphate particles was strongly dependent on the flow rate of the reactants in the microchannel and high flow rate was beneficial for producing small particles. Furthermore, it was possible to control the average particle size in the range from 30 to 150nm by changing the reactant concentrations and the micropore size on the surface of the inner tube. The average particle size decreased by increasing the total flow rate and reactant concentrations or decreasing the micropore size. The dispersed-phase flow rate and mixing distance exhibited little effects on the particle size. The proposed microreactor concept was confirmed to be valid and promising for the industrial production of nanoparticles. [Copyright &y& Elsevier]

This article presents a new microporous tube-in-tube microchannel reactor (MTMCR) with high throughput and excellent micromixing performance. In the MTMCR, one liquid from the inner tube is divided into many liquid fragments through the microscale pores in the walls, and then these fragments vertically collide with another flowing annular liquid sheet between the inner and outer tubes, generating cross-flow. The annular microchannel allows a mass of fluid to go through it rapidly without enlarging the channel width, thereby achieving a throughput as high as 9 L/min (typical microreactor throughput = 4−100 mL/min). Furthermore, the micromixing performance is expressed in terms of a segregation index, which can be as low as 0.0007. The micromixing time evaluated by the incorporation model reaches the magnitude of milliseconds. In addition, several factors affecting the micromixing such as reactant concentration, flow rate, volume flow ratio, micropore size, and channel width were investigated. The results indicated that an increase of the flow rate, as well as a reduction of the micropore size and channel width, could greatly intensify the micromixing. Therefore, it can be envisioned that the MTMCR would exhibit great potential for various industrial applications in the future. [ABSTRACT FROM AUTHOR]

Highlights: [•] Microporous tube-in-tube microchannel is a high-throughput device to produce emulsions. [•] An O/W emulsion throughput of 5L/min could be achieved. [•] Anionic and nonionic surfactants were more suitable for preparing stable O/W emulsions. [•] Smaller micropore size and annular channel width could generate smaller droplet diameter. [•] Micropore size has the larger effect on the emulsification pressure drop of this device. [Copyright &y& Elsevier]

Abstract: An approach to fabricate Cu@SiO2 nanostructured materials was presented by using Cu nanoparticles (NPs) produced in a tube-in-tube microchannel reactor (TMR) as the core. Due to the excellent micromixing efficiency of the TMR, monodisperse Cu NPs of sub-5nm were easily obtained. A combination of the direct silica-coating technique with the remarkable ability of the TMR for mass production of nanoparticles may open an economic pathway for producing core-shell nanomaterials. [Copyright &y& Elsevier]

Highlights: [•] Microporous tube-in-tube microreactor is a high-throughput device for CO2 capture. [•] The high volume mass transfer coefficient and CO2 removal efficiency were achieved. [•] Effects of design and operating parameters were studied to optimize the conditions. [•] The alkanolamine solutions of 10wt.% MDEA and 4wt.% PZ were used as absorbents. [•] Smaller micropore size and annular channel width led to higher mass transfer efficiency. [Copyright &y& Elsevier]