Type Of Contactor Research Articles

Magnetic resonance velocimetry of thin falling films

Falling film microreactors are a type of liquid–gas contactor based on a gravity-driven film flow. These devices achieve high interfacial areas per unit volume compared to other contactors. Nevertheless, they are limited by the liquid-side mass transfer. To overcome this issue, the operating conditions must be chosen in a way to enhance gas absorption and ensure efficient transfer within the film. The present study looks into the use of magnetic resonance velocimetry to study the velocity field inside of falling films at the microscale. Two parameters were considered, the channel geometry, and the volumetric flow rate. The aim was not only to determine the conditions that optimize the interfacial area, but also to showcase the capabilities and advantages of magnetic resonance velocimetry for this type of flow configuration. In addition, a straightforward mathematical model, based on the Navier–Stokes equations, is used to predict the thickness of the film, since previous approaches, mainly those of Kapitza and Nusselt, are not valid for flows at the microscale, where surface tension phenomena predominate. It was shown that the round channel yields by far the highest surface-to-volume ratio, twice as high as for the rectangular channel for the same volumetric flow rate. In addition, film breakup was not observed in the round channel even for volumetric flow rates of down to 0.27mLmin−1.

Pengaplikasian Metode Peramalan untuk Mengoptimalkan Perencanaan Persediaan Suku Cadang (Studi Kasus: Suku Cadang Contactor di PT. Semen Padang)

Based on data in-out of spare parts at PT. Semen Padang, contactor type is one of the electrical spare part that have a high throughput rate compare the other sparepart type. In addition, contactors also have a high price and also needs to be stored with special treatment in the spare part warehouse. Furthermore, currently the company has not used a specific methods in determine the material requirement planning for the spare parts. Therefore in this study it is purposed to use a forecasting methods to determine the contactor requirement planning to avoid losses. Quantitaive forecasting methods was used in this study such as quadratic, cyclical, and cyclical methods. The best forecasting method is determined based on the smallest error value of the four compared methods. Contactor requirement planning is carried out by forcasting for the next 24 periods. Based on the results, it is found the best methods that has the smalles MAPE error (45%) is the Cyclic Method. The forecasting results obtained show the similarity of the trend with the historical data used, so that this forecasting method can be considered for use in material requirement planning of spare parts specially for contactor types at PT. Semen Padang.

Studies on a Novel Jet Mixer in the Extraction Process

This paper presents the original results of research on an inline jet mixer being an alternative to other, conventional mixing apparatuses used for extraction processes. In particular, researched novel geometry of a jet mixer was subjected to testing of either hydraulic performance or a liquid–liquid extraction process. Inline jet mixers are well suited for mixing gases and liquids and can be used in such processes as extraction, heat exchange, and reaction. In such an apparatus, mixing of liquids takes place by high-velocity injection of one stream into another through a series of small holes placed peripherally to a concentrically mounted inner tube. The literature lacks the data to allow for the design of these types of mixers. Extraction experiments were performed for the ethyl acetate–ethanol–water system. The research results presented in this paper enable the calculation of mixing power and the selection of optimal mixer operating parameters. Equations describing the flow resistance for both streams were developed. The mixing power was calculated and compared with other types of contactors. The data on overall volumetric mass transfer coefficients obtained by this study showed that the considered extractor is competitive with other conventional contactors at almost identical or even lower energy consumption.

Characterisation and perspectives of energetic use of dissolved gas recovered from anaerobic effluent with membrane contactor

Biogas is a source of renewable energy, and its production and use has been validated in anaerobic-based sewage treatment plants (STPs). However, in these systems, a large amount of methane is lost as dissolved methane (D-CH4) in the liquid effluent. In this study, the characteristics and potential energetic uses of the gas recovered during the desorption of D-CH4 from anaerobic effluents with hollow fibre membrane contactors were investigated. A pilot-scale experiment was performed using sewage and two types of membrane contactors. The recovered gas contained considerable amounts of CH4, CO2, H2S, N2, and O2; therefore, a gas upgrade is required prior to its use as a biofuel. The recovery process should be energetically self-sustainable, and induce a considerable decrease in the STP carbon footprint. Recovering D-CH4 with membrane contactors could increase the energetic potential of anaerobic-based STPs up to 50 % and allow for more sustainable systems.

Efficiency evaluation of satellite detumbling using a brush type contactor based on flexible multibody dynamics

Detumbling manipulation to capture a noncooperative space satellite using a brush type contactor is getting more and more attention due to its lower cost and easy implementation. It is important to evaluate the effects of various modal parameters on the detumbling efficiency, including the design of the brush contactor and the manipulation schemes. In this study, a simplified planar multibody dynamic model is established to estimate the detumbling efficiency. An analytical formula is proposed based on some assumptions from the aspect of energy. Several model parameters are considered in the formula including the brush's bending stiffness and length, the contact position and angle. Concerning the numerical strategies, the planar corotational beam element is adopted to discretize the brush contactor undergoing large displacement and large rotations while the motion of the solar panel undergoing small deformation is modelled by the floating frame of reference formulation. The contact force between the brush contactor and the solar panel is described by the Hertz contact law. The results show that the analytical formula can give a rough estimation to the reduced kinetic energy even if dumping forces are considered. It can be found that a short brush contactor with high bending stiffness can improve the detumbling efficiency. Moreover, touching the solar panel near the root of the brush contactor and maintaining a small contact angle are both efficient manipulations.

Research on the theoretical basis for engineering application of transport membrane condenser

Membrane separation technology is an important technology for efficient recovery of resources in the industrial production processes. Transport membrane condenser is a new type of membrane contactor which can recover moisture and waste heat from flue gas. In order to promote the large-scale industrial application of transport membrane condenser, several engineering experiments are designed in this paper. Based on the quantitative results, the effects of particulate matter in flue gas, cooling water physical parameters, porous ceramic membrane reliability and energy grade are analyzed. For engineering application, a series of suggestions are put forward. It includes setting microporous ceramic membranes before transport membrane condenser to capture particulate matter, designing the double circulating cooling water system, adopting the multi-stage transport membrane condenser arrangement, and using the recovered hot water to heat the feed water of No. 8 heater or shaft gland heater in the coal-fired power plant. These results effectively build a bridge between theoretical research and engineering application, and realize the guidance of theory to engineering.

Dynamic modeling and analysis of satellite detumbling using a brush type contactor based on flexible multibody dynamics

A brush type contactor has been proposed to detumble non-cooperative space targets. Current researches mainly focused on the control schemes and their validations, whereas the dynamic modeling is rarely investigated. In this paper, both the analytical formulation and the numerical approach are employed to establish the dynamic model of the detumbling system. An analytical formula is proposed to evaluate the detumbling efficiency from the aspect of energy. The numerical simulation is conducted using flexible multibody dynamics and the contact theory. The analytical results and the numerical results are compared and the influence of various model parameters on dynamic behaviors is studied. It shows that the detumbling efficiency can be significantly affected by several factors, including the stiffness and length of the brush, the end velocity of the contactor, the contact angle, and the contact position. The detachment phenomenon of the brush from the solar panel is investigated. A criterion for the detachment is proposed and verified by numerical simulations.

Advances in absorbents and techniques used in wet and dry FGD: a critical review

Abstract Sulfur dioxide is considered as an extremely harmful and toxic substance among the air pollutants emitted from the lignite- and other high-sulfur-coal based power plants, old tires processing units, smelters, and many other process industries. Various types of absorbents and desulfurization technologies have been developed and adopted by the industries to reduce the emission rate of SO2 gas. The present paper focuses on the ongoing advances in the development of varieties of regenerative and non-regenerative absorbents viz., Ca-based, Mg-based, Fe-based, Na-based, N2-based, and others along with various FGD technology, viz., wet, dry or semi-dry processes. Additionally, different types of contactors viz., packed column, jet column, spray tower, and slurry bubble columns along with their significant operational and design features have also been discussed. In the existing or newly installed limestone-based FGD plants, an increasing trend of the utilization of newly developed technologies such as limestone forced oxidation (LSFO) and magnesium-enhanced lime (MEL) are being used at an increasing rate. However, the development of low-cost sorbents, particularly suitable solid wastes, for the abatement of SO2 emission needs to be explored sincerely. Many such wastes cause air pollution by way of entrainment of fine particulate matter (PM), groundwater contamination by its leaching, or brings damage to crops due to its spreading onto the cultivation land. One such pollutant is marble waste and in this work, this has been suggested as a suitable substitute to limestone and cost-effective sorbent for the desulfurization of flue gases. The product of this process being sellable in the market or may be used as a raw material in several industries, it can also prove to be an important route of recycling and reuse of one of the air and water-polluting solid wastes.

Simultaneous Biogas Upgrade and Production of Precipitated Calcium Carbonate

Biogas upgrading is a necessary step to remove impurities and increase a calorific value of biogas before it can be used as a proper energy source. The most significant impurity in raw biogas is typically carbon dioxide, composing up to 50% of biogas volume. Carbon dioxide capture is therefore an important part of the upgrading process which in turn raises the question of the availability of final carbon storage. This problem can be addressed by using calcium hydroxide solution or other lime-based solvents as scrubber in carbon dioxide capture via carbonation where precipitated calcium carbonate (PCC) is formed as a by-product. This paper reviews the viability of packed column, bubble column, and spray column for simultaneous biogas purification by CO2 capture and PCC synthesis, as well as examining various parameters that affect both carbon dioxide capture and the production of PCC. Among the three reviewed types of contactors, only packed column is deemed unsuitable for the simultaneous process. The optimal condition for both carbon dioxide scrubbing efficiency and PCC yield can be obtained by using a high liquid flow rate, low gas flow rate, and high solvent concentration. However, the desired characteristics of PCC should be considered in determining the operating parameters as the said characteristics such as crystal phase, morphology, and particle size are affected by several operating parameters, namely gas flow rate, solvent concentration, temperature, size of bubbles, and concentration of additives.

MOFs in carbon capture-past, present and future

• Microwave assisted solvo-thermal synthesis was found promising.· • Cu-BTC gave the highest CO 2 uptake was 9.59 mmol/g among various MOFs.· • Adsorption of CO 2 by MOFs mostly followed Pseudo second order kinetics along with Toth or modified Langmuir isotherm.· • Fixed and fluid bed type of contactors were the best suited for MOF based Carbon capture· • Photo-responsive MOFs have a great potential in future that could give a CO 2 uptake of 89 cc/g. Metal Organic Frame works (MOFs) are being widely used in carbon capture through adsorption and membrane techniques, which are yet to be commercialized. This is due to their high affinity towards acidic gases and exceptional characteristics such as crystallinity, structural stability, high surface area and flexible pore dimensions. In this review, wide range of topics viz., synthesis protocols, modifications employed to further improve their attributes, comprehensive comparison of different MOFs used in carbon capture, thermo-kinetics modelling studies, contactors and material screening. Every section has been discussed in detail in terms of developmental trends, future challenges and prospects besides summarizing in the form of comprehensive tables at a glance for the benefit of the readers. Solvo-thermal method was found to be the most effective synthesis method besides ultra-sonication and microwave assisted methods, which also gave very good crystalline structures. The copper ligand based unmodified Cu-BTC MOF gave the maximum CO 2 uptake value of 9.59 mmol/g at 273 K and 1 atm. Zn(Bmic)(AT) MOF was the only species to be tested at 353 K. Alternatively, a photo-responsive MOF, Mg-IRMOF-74-III functionalized with azopyridine gave a CO 2 uptake of 89 cc/g which is comparable to many of the conventional MOFs. Kinetics indicate MOF adsorption mostly follows pseudo second order reactions either along with Toth isotherms or modified Langmuir isotherms. Fixed and fluidized bed reactors perform the best in terms of carbon capture studies. Moisture affinity, active sites and crystallinity were found to be the best factors considered whilst screening of proper MOFs.

Switching-On Operation of an Electromagnetic Relays Optimization Using a Phase Control Approach

The presented research activities deals with the idea of electromagnetically actuated switching devices switching- on process improvement by means of an electronic controller application. Based on the analysis of the results of the electromagnetic contactors dynamic at switching- on selection, the most efficient condition was determined. Making process improvement methods based on the principle of controlling the supply voltage phase were presented in this article: selected dynamic parameters at switching- on optimization in view of its parameters values minimization and intelligent compensation of the movable armature inertia using predictive control of the driving coil supply voltage. Experimental verification of the developed controller confirmed its applicability for various contactor types. Tested objects increased its ability for “near to zero,” switching- on operation realization and selected parameters optimization without the necessity of device construction modification.

Characterization of liquid–liquid mass transfer performance in a novel pore‐array intensified tube‐in‐tube microchannel

AbstractLiquid–liquid mass transfer performance of a novel pore‐array intensified tube‐in‐tube microchannel (PA‐TMC) was investigated with the water‐benzoic acid‐kerosene system. Both mass transfer efficiency (E) and volumetric mass transfer coefficient (K La) are found to increase simultaneously with the flow rate, but decrease with total number of pores and rows. However, E increases but K La decreases with the annular length. In particular, the pore size shows an optimal value at 0.3 mm due to the interplay problem of the radial adjacent pores. Computational fluid dynamics simulations reveal that the high kinetic energy generated by the pore‐array section plays a significant role in mass transfer process. The artificial neural network model is established to correlate K La with the investigated parameters of PA‐TMC. The comparison of K La with other types of contactors indicates that PA‐TMC has superior mass transfer performance and high throughput for a broad industrial application.

Experimental and modeling of CO2 removal from gas mixtures using membrane contactors packed with glass beads

The efficiency of gas removal using hollow fiber membrane (HFM) contactors and liquid solvents is determined by several factors. The liquid film resistance has been identified as one of the important factors affecting the overall mass transfer coefficient. The present work describes the use of spherical glass beads as additional packing in the shell (solvent) side to act as solid baffles which should impart stirring effect in the flowing solvent and increase its velocity. These two effects should decrease the liquid film resistance and consequently enhance the gas removal efficiency. Two types of custom-made hollow fiber membrane contactors (HFMC) were constructed from thick-walled acrylic tube (20 mm ID, OD 30 mm) and equipped with the commercially available poly(tetrafluoroethylene-co-perfluorinated alkyl vinyl ether) (PFA) hollow fibers. In one type of the contactors, glass beads were introduced in the shell side. The two types of contactors (with and without beads) were tested and compared in terms of CO2 removal efficiency from gas mixtures (5% CO2 − 95% CH4) using aqueous sodium hydroxide and several amine solutions. Different parameters were studied to evaluate the performance of the membrane contactors at feed gas pressures up to 25 bars. The obtained results indicated an increase of up to 21% enhancement in CO2 removal efficiency when the shell compartment was packed with the glass beads. The results obtained from the overall mass transfer coefficient model showed good agreement with those of the experimental data.

Analysis of Electrical Life Distribution Characteristics of AC Contactor Based on Performance Degradation

Electrical life is an important performance indicator of ac contactor, and it is influenced by various factors, among which the most important one is arc erosion caused by arc current. This paper proposes a general contact erosion model based on arcing phase angle to simulate the electrical life distribution characteristics of ac contactor under random breaking operations. For the same type of ac contactor, different individuals have different electrical life due to the manufacturing dispersion, so the normal distribution is utilized to simulate the manufacturing dispersion under $3\sigma $ standard. The simulation results show that the electrical life distribution is closely related to the manufacturing dispersion degree. When the dispersion degree of manufacturing processes is relatively low, the electrical life obeys three-parameter Weibull distribution. Otherwise, the electrical life of contactors obeys normal distribution. Finally, the electrical life test is performed, and the test results are consistent with the theoretical analysis results. The abovementioned conclusion provides theoretical foundation for the reliability evaluation and experimental study of ac contactor.

Thermal modelling and parametric investigations on coupled heat and mass transfer processes occurred in a packed tower

Packed towers are the most preferable type of contactors for achieving better heat and mass interactions between the air and the working fluids. In the present study, a thermodynamic model is developed for analyzing the heat and mass transfer interaction between air and working fluid along a counter/parallel flow packed tower (dehumidifier, regenerator and cooling tower). An algorithm using a backtracking approach is introduced for simulating the transfer processes in the packed tower. The predicted simulation results are in good agreement with the experimental data available in the literature for the counter/parallel flow packed tower. The contour plots are developed for analyzing the transfer processes along the height of the packed tower. The performances of the dehumidifier, the regenerator and the cooling tower are predicted at various operating conditions and tower specifications.

A Multi‐Stream Microchip for Process Intensification of Liquid‐Liquid Extraction

AbstractSolvent extraction is a critical step in many industrial mineral‐processing circuits and is affected by chemical (e.g., metal ions, extractant, pH, reaction rate) and physical (e.g., interfacial phenomena, mass transport, temperature) factors. Here, a new type of microfluidic contactor is presented that enables higher volumetric throughputs and straightforward counter‐current operation compared with Y‐Y chips. A single chip design can handle a wide range of organic/aqueous phase ratios, thereby enabling stable operation for non‐ideal solutions and fluctuating flow. An expression defining this widened operational window has been derived based on the relative stream geometries and liquid viscosities. A two‐stage counter‐current circuit is demonstrated for the extraction of platinum(IV) chloride.

Understanding the Impact of Process Design on the Cost of CO2 Capture for Precipitating Solvent Absorption

There has been increasing interest in the development of solvents for CO2 capture including solvents that involve precipitation during CO2 absorption. On the basis of Le Chatelier’s principle, the CO2 absorption equilibrium can be shifted by removing one of the reaction products, resulting in a higher absorption capacity. Two phase-change solvents are investigated: promoted potassium carbonate (where the CO2 is incorporated in the solid phase) and potassium taurate (where the CO2 is incorporated in the liquid phase). A high-level assessment is performed with the two phase-change solvents in order to identify key areas in solvent system design for possible cost reduction. The impacts of absorption contactor type, the addition of a solid–liquid separator, and heat integration opportunities on capture cost and total heat duty are investigated. For both phase-change solvents, the lowest capture cost is found when the CO2 absorption is operated in a packed column and advanced heat exchanger integration is used...

Performance evaluation of composite and microporous gas–liquid membrane contactors for CO2 removal from a gas mixture

Hollow fiber membrane contactors with microporous polypropylene (PP) and composite polytetrafluoroethylene/polyethersulfone (PTFE/PES) were used for carbon dioxide (CO2) removal from a gas mixture. The composite membranes exhibited higher efficiency than the microporous membranes, which was related to prevention of pore wetting due to the PTFE present in the top layer of the membrane. For both type of contactors, it was investigated the influence of liquid flow rate, temperature and kind of absorbent on the CO2 removal. A better performance of CO2 transfer into the liquid phase was observed by increasing the liquid flow rate, by using a reacting absorbent (sodium hydroxide) and by decreasing the liquid temperature.

Power Consumption, Mixing Time, and Oxygen Mass Transfer in a Gas-Liquid Contactor Stirred with a Dual Impeller for Different Spacing

Multiple or dual impellers are widely implemented in stirred contactors used in various biological processes like fermentation, water treatment, and pharmaceutical production. The spacing between impellers is considered as a crucial factor in designing of these types of contactors resulting in variation of oxygen mass transfer, mixing time, or power consumption for such biological system. A study of three parts was conducted to characterize the effect of the spacing between impellers on the most important parameters that related to biological contactor performance: oxygen mass transfer coefficientklafrom the gas phase (air) to the liquid phase (water), mixing time, and power consumption for different operating rotational speeds (1.67–3.33 rps) and for three different spacing positions. The used impellers system in the study is a dual impeller system which consists of an inverted and bladed rotated cone (IBRC) and a pitched-blade up-flow propeller (PBPU). The experimental results showed that the shorter spacing (the lower PBPU in a higher position) is more convenient, as the achieved oxygen mass transfer coefficient has showed an improvement in its values with lower mixing time and with a slight alteration in power consumption.

A Novel Residual Electrical Endurance Prediction Method for Low-Voltage Electromagnetic Alternating Current Contactors

This paper proposes a novel residual electrical endurance (REE) prediction modeling method for low-voltage electromagnetic alternating current (ac) contactors based on conditional density estimation (CDE). For a type of ac contactor, the current REE value is defined by the ratio of the current operation number against its maximum operation number. Voltage and current signals between contacts during breaking processes are acquired as the initial data. An arcing characteristic set of every breaking process is computed from the voltage/current signals, and the characteristic sets are grouped and averaged to achieve training and testing data sets. Four data schemes are applied and compared. CDE modeling with cross-validation is performed on the training data set to build REE prediction models, which are then applied to estimate the REEs of testing observations. The experiment proves that the modeling method is able to reach relatively precise predictions.