scholarly journals Synthesis of Thin Titania Coatings onto the Inner Surface of Quartz Tubes and Their Photoactivity in Decomposition of Methylene Blue and Rhodamine B

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1538
Author(s):  
Stanislav D. Svetlov ◽  
Dmitry A. Sladkovskiy ◽  
Kirill V. Semikin ◽  
Alexander V. Utemov ◽  
Rufat S. Abiev ◽  
...  

An evaporation-deposition coating method for coating the inner surface of long (>1 m) quartz tubes of small diameter has been studied by the introduction of two-phase (gas-liquid) flow with the gas core flowing in the middle and a thin liquid film of synthesis sol flowing near the hot tube wall. The operational window for the deposition of continuous titania coatings has been obtained. The temperature range for the deposition of continuous titania coatings is limited to 105–120 °C and the gas flow rate is limited to the range of 0.4‒1.0 L min−1. The liquid flow rate in the annular flow regime allows to control the coating thickness between 3 and 10 mm and the coating porosity between 10% and 20%. By increasing the liquid flow rate, the coating porosity can be substantially reduced. The coatings were characterized by X-ray diffraction, N2 chemisorption, thermogravimetric analysis, and scanning electron microscopy. The coatings were tested in the photocatalytic decomposition of methylene blue and rhodamine B under UV-light and their activity was similar to that of a commercial P25 titania catalyst. 

1986 ◽  
Vol 51 (10) ◽  
pp. 2127-2134 ◽  
Author(s):  
František Potůček ◽  
Jiří Stejskal

Absorption of oxygen into water and aqueous solutions of poly(acrylamides) was studied in an absorber with a wetted sphere. The effects of changes in the liquid flow rate and the polymer concentration on the liquid side mass transfer coefficient were examined. The results are expressed by correlations between dimensionless criteria modified for non-Newtonian liquids whose flow curve can be described by the Ostwald-de Waele model.


Author(s):  
Svetlana Rudyk ◽  
Sami Al-Khamisi ◽  
Yahya Al-Wahaibi

AbstractFactors limiting foam injection for EOR application are exceptionally low rock permeability and exceedingly high salinity of the formation water. In this regard, foam formation using internal olefin sulfonate is investigated over a wide salinity range (1, 5, 8, 10, and 12% NaCl) through 10 mD limestone. The relationships between pressure drop (dP), apparent viscosity, liquid flow rate, total flow rate, salinity, foam texture, and length of foam drops at the outlet used as an indicator of viscosity are studied. Foaming is observed up to 12% NaCl, compared to a maximum of 8% NaCl in similar core-flooding experiments with 50 mD limestone and 255 mD sandstone. Thus, the salinity limit of foam formation has increased significantly due to the low permeability, which can be explained by the fact that the narrow porous system acts like a membrane with smaller holes. Compared to the increasing dP reported for highly permeable rocks, dP linearly decreases in almost the entire range of gas fraction (fg) at 1–10% NaCl. As fg increases, dP at higher total flow rate is higher at all salinities, but the magnitude of dP controls the dependence of apparent viscosity on total flow rate. Low dP is measured at 1% and 10% NaCl, and high dP is measured at 5, 8, and 12% NaCl. In the case of low dP, the apparent viscosity is higher at higher total flow rate with increasing gas fraction, but similar at two total flow rates with increasing liquid flow rate. In the case of high dP, the apparent viscosity is higher at lower total flow rate, both with an increase in the gas fraction and with an increase in the liquid flow rate. A linear correlation is found between dP or apparent viscosity and liquid flow rate, which defines it as a governing factor of foam flow and can be considered when modeling foam flow.


Author(s):  
Yoshiyuki Iso ◽  
Xi Chen

Gas-liquid two-phase flows on the wall like liquid film flows, which are the so-called wetted wall flows, are observed in many industrial processes such as absorption, desorption, distillation and others. For the optimum design of packed columns widely used in those kind of processes, the accurate predictions of the details on the wetted wall flow behavior in packing elements are important, especially in order to enhance the mass transfer between the gas and liquid and to prevent flooding and channeling of the liquid flow. The present study focused on the effects of the change of liquid flow rate and the wall surface texture treatments on the characteristics of wetted wall flows which have the drastic flow transition between the film flow and rivulet flow. In this paper, the three-dimensional gas-liquid two-phase flow simulation by using the volume of fluid (VOF) model is applied into wetted wall flows. Firstly, as one of new interesting findings in this paper, present results showed that the hysteresis of the flow transition between the film flow and rivulet flow arose against the increasing or decreasing stages of the liquid flow rate. It was supposed that this transition phenomenon depends on the history of flow pattern as the change of curvature of interphase surface which leads to the surface tension. Additionally, the applicability and accuracy of the present numerical simulation were validated by using the existing experimental and theoretical studies with smooth wall surface. Secondary, referring to the texture geometry used in an industrial packing element, the present simulations showed that surface texture treatments added on the wall can improve the prevention of liquid channeling and can increase the wetted area.


Author(s):  
N.I. Mikheev ◽  
V.M. Molochnikov ◽  
D.V. Kratirov ◽  
O.A. Dushina ◽  
A.A. Paereliy ◽  
...  

2007 ◽  
Vol 50 (6) ◽  
pp. 641-650
Author(s):  
V. B. Bol’shakov ◽  
N. I. Kosach

Author(s):  
Yuanyuan Chen ◽  
Jing Gong ◽  
Xiaoping Li ◽  
Nan Zhang ◽  
Shaojun He ◽  
...  

Pipeline commissioning, which is a key link from engineering construction to production operation, is aim to fill an empty pipe by injecting water or oil to push air out of it. For a large-slope crude oil pipeline with great elevation differences, air is fairly easy to entrap at downward inclined parts. The entrapped air, which is also called air pocket, will cause considerable damage on pumps and pipes. The presence of it may also bring difficulties in tracking the location of the liquid head or the interface between oil and water. It is the accumulated air that needed to be exhausted in time during commissioning. This paper focuses on the simulation of liquid-gas replacement in commissioning process that only liquid flow rate exists while gas stays stagnant in the pipe and is demanded to be replaced by liquid. Few previous researches have been found yet in this area. Consequently, the flow in a V-section pipeline consisted of a downhill segment and a subsequent uphill one is used here for studying both the formation and exhaustion behaviors of the intake air. The existing two-fluid model and simplified non-pressure wave model for gas-liquid stratified flow are applied to performance the gas formation and accumulation. The exhausting process is deemed to be a period in which the elongated bubble (Taylor bubble) is fragmented into dispersed small bubbles. A mathematical model to account for gas entrainment into liquid slug is proposed, implemented and incorporated in a computational procedure. By taking into account the comprehensive effects of liquid flow rate, fluid properties, surface tension, and inclination angle, the characteristics of the air section such as the length, pressure and mass can be calculated accurately. The model was found to show satisfactory predictions when tested in a pipeline. The simulation studies can provide theoretical support and guidance for field engineering application, which are meanwhile capable of helping detect changes in parameters of gas section. Thus corresponding control measures can be adopted timely and appropriately in commissioning process.


2000 ◽  
Vol 33 (2) ◽  
pp. 211-216 ◽  
Author(s):  
Meisen Li ◽  
Yoshiyuki Bando ◽  
Kenji Suzuki ◽  
Keiji Yasuda ◽  
Masaaki Nakamura

2011 ◽  
Vol 7 (1) ◽  
pp. 17-31
Author(s):  
Eleonóra Kecskés-Nagy ◽  
Milan Koszel ◽  
István Sztachó-Pekáry

The objective of the work was to determine the influence of working pressure and working speed on drop tracks size and changes in flow rate of flat fan nozzles. New nozzles and nozzles after laboratory wear were tested. The influence of nozzles wear on drop tracks size was tested. It was found that the increase in liquid flow rate resulted in higher values of mean diameter of the droplet track. The increase in working pressure or working speed causes decrease in drop tracks size and reduction in merging of droplets on sprayed surface. The increase of the wear was followed by increased coverage rate. This phenomenon is especially dangerous when using nozzles with a considerable wear for agricultural spraying since this causes ecological threat to environment.


2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
I. I. Esen

Hydraulic performance of an airlift pump having a rectangular cross-section 20 mm × 80 mm was investigated through an experimental program. The pump was operated at six different submergence ratios and the liquid flow rate was measured at various flowrates of air injected. The effectiveness of the pump, defined as the ratio of the mass of liquid pumped to the mass of air injected, was determined as a function of the mass of air injected for different submergence ratios. Results obtained were compared with those for circular airlift pumps using an analytical model for circular pumps. Effectiveness of the rectangular airlift pump was observed to be comparable to that of the circular pumps. Hydraulic performance of the rectangular airlift pump investigated was then described by a set of semilogarithmic empirical equations.


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