Compressed Air Flow Rate Research Articles

Study of inhalation micropowders obtained by spray drying

Objectives. To study the influence of the type of matrix-forming material and excipients concentration, spray drying parameters on the characteristics of the powder for inhalation, as well as to investigate the inhalation compositions for stability under stressful conditions.Methods. Spray drying was used to obtain powder compositions with the required characteristics for inhalation therapy. Microscopic and analytical studies of powders were carried out. Statistical analysis made it possible to estimate the influence of factors on the powder characteristics and rank them by importance. The stability of spray dried powders was studied.Results. The optimal parameters for obtaining powders for inhalation were found by means of mathematical statistics: air flow rate was 37 m3/h; compressed air flow rate — 601 L/h; inlet air temperature — 150°C; solution flow rate — 45% of the power of the peristaltic pump (16.3 g/min for this composition); L-leucine concentration — 10 wt %; ratio of components of the matrix polyvinylpyrrolidone K-30/D-mannitol = 1 : 3. Under these conditions, as well as by means of 2 experiments additionally selected from the research design, a composition with isoniazid as an active substance was spray dried. The resulting powders were analyzed, in order to confirm the correctness of the recommended parameters.Conclusions. The selection of compositions and spray drying conditions involves multiple criteria. The characteristics of the powder for inhalation may deteriorate significantly during long-term storage. The optimal parameters were determined using statistical analysis and confirmed by experimental data.

Analysis of energy and exergy of lavender extract powder in spray dryer

AbstractIn recent years, the research in the field of medicinal plants as therapeutic supplements has increased significantly. Lavender extract is widely used among medicinal plant products due to its unique therapeutic properties. Since drying processes require high energy, this study was conducted to study the performance of the spray dryer in the production of lavender extract powder at three levels of air temperature 150°C, 180°C, and 210°C, three levels of compressed air flow rate 6, 8, and 10 L/min and ratios of maltodextrin‐drying aid to the mass of dry matter of the extract 0%, 25%, and 50% by response surface method. For this purpose, the energy efficiency and exergy of the powder production process were examined. According to the obtained results, increasing the inlet air temperature and the inlet air flow rate increased the energy efficiency and exergy and decreased the energy efficiency and exergy, respectively. The energy efficiency of the drying process varied in the range of 6.55%–15.87%, and the exergy efficiency () of the drying process in the range of 2.87%–5.84%. Also, the of the spray dryer was calculated in the range of 20.05%–38.78%. Based on the energy efficiency and exergy, the optimal production of lavender plant extract powder was obtained at the air temperature of 210°C, the compressed air flow rate of 6 L/min, and the amount of drying aid of 11.9 g/L.

The effect of spray drying parameters on drying of magnesium silicate hydroxide microspheres

Magnesium hydroxide silicate (MSH), as an antiwear additive for lubricating oil, effectively solves the problem that conventional additives contain chlorine, phosphorus and sulfur, which are harmful to environment. However, it is ineffective to prepare MSH powder by traditional drying combined with mechanical ball milling. So the purpose of this study is to prepare smooth MSH microspheres with controllable particle size and moisture content by adjusting spray drying parameters based on hydrothermal synthetic MSH suspension. Results showed that the particle size of MSH microsphere was reduced from 5.5 ± 2.9 μm to 2.78 ± 1.37 μm, and the moisture content was reduced from 7.3% to 4.43% by decreasing solid-liquid ratios and rotating speed of peristaltic pump, or raising inlet temperature of hot air, flow rate of compressed gas and inlet air. In addition, due to the surface energy difference at the interface between liquid-gas and solid-gas during the drying process, nano flaky MSH continuously moved to the center of the droplet, and the capillary force generated by gaps between MSH nanosheets discharges the moisture in the wet core, so that the MSH nanosheets gather and finally form dense and smooth MSH microspheres.

ASSESSING AND IMPROVING COMPRESSED AIR NETWORK IN UNDERGROUND MINES (A CASE STUDY IN IRAN)

Compressed air is one of the most common methods of energy transfer in industrial and mining systems. Compressed air has numerous applications in underground mines to ensure safety (ventilation fans), carry out extraction operations (compressed air equipment and machines), and manage technical services like dewatering and the operating of spare equipment. Therefore, it is necessary to investigate the compressed air supply systems in mines to assess the sufficiency of compressed air, reduce energy consumption, and lower operating costs. Considering the significance of utilizing compressed air in underground mines, it is essential to verify the adequacy of the flow rate and permissible pressure of compressed air for all mine air consumers. This requires proper design and adjustment of the compressed air distribution network. In this paper, the compressed air network in the main compressor house of the Qaleh-Zari copper mine in Iran was investigated. To achieve this goal, the compressed air consumption in various mining operation conditions was investigated and discussed after surveying the airflow transmission lines. The pressure drops in each line were estimated as well. Regarding the results, the airflow consumption in regular mining operations is about 36 cubic meters per second. The drop in air pressure within the network lines is below the permissible limit, but the overall pressure drop is significant. In this approach, practical adjustments such as changing the diameter of the pipes, increasing the airflow pressure, and utilizing local compressors near consumers’ locations were proposed and investigated.

Encapsulation of açaí (Euterpe oleracea) pulp with whey protein isolate by spray-drying: An optimization study using response surface methodology (RSM)

Açaí fruit (Euterpe oleracea) is a rich source of bioactive compounds such as anthocyanins and flavonoids in general. However, once anthocyanins are easily degradable, efforts have been made toward the development of methods for preserving them from degradation throughout industrial processing. The objective of this study was to optimize the encapsulation of açaí pulp with whey protein isolate by spray drying. For this purpose, the Central Composite Rotational Design (CCRD) with response surface methodology (RSM) was applied to evaluate the influence of inlet temperature (Te), drying air flow rate (VA), and compressed air flow rate (VB) on the following response variables: encapsulation yield, water activity, hygroscopicity, density, ash, and protein, in addition to the content of the bioactive compounds anthocyanins and flavonoids. The coefficient of determination (R²) of CCRD ranged between 0.87 and 0.97, and the sum of squared error (SSE) varied from 0.0003 to 14505, indicating an adequate performance of this experimental design. In general, the optimization analysis showed that Te between 150 and 165 °C, VA below 2.9×10−5 m³ /s and VB less than 0.0006 m³ /s favored the minimization of water activity and hygroscopicity, 0.25 and 2.9 g/100 g, respectively, the maximization of density, and encapsulation yield (around 45%), as well as the preservation of both the anthocyanins (170 mg .100 g−1) and flavonoids (420 mg. 100 g−1), respectively, obtaining a high-quality product. This study represents a first step in the encapsulation of açaí, aiming not only to preserve its bioactive compounds but also to provide a product with a rich protein source, such as whey protein. Ultimately, this research offers potential industrial production alternatives, opens up a new field of study, and presents a potential new market opportunity for small, medium, and even large-scale producers.

Optimization of Humidification-Dehumidification solar desalination Unit: Comparative analysis

Water is essential for life on Earth. By turning saline water into drinkable water, desalination technology may help solve water scarcity. The present work uses artificial neural networks and the response surface approach to discuss freshwater production through a humidification-dehumidification solar-powered desalination unit with a pneumatic sprayer. The compressed air flow rate, air pressure, and time on productivity desalinated by the proposed system are investigated. The designed artificial neural networks model indicated that responses are close to the observed findings. It is shown that the generated models can be utilized to predict productivity and accumulated productivity within the investigation area. The optimum parameters for maximum accumulated productivity are 150 L/min compressed air flow rate, 7 bar air pressure, and 16o'clock to achieve the maximum accumulated freshwater productivity of 19.4 L/day. The comparative results reveal higher precision in the artificial neural networks model than in the response surface methodology approach.

Three-Fluid Nozzle Spray Drying Strategy for Efficient Fabrication of Functional Colloidosomes.

Colloidosomes as Pickering emulsion microcapsules are expected to serve various applications, including encapsulation of drugs and loading of functional materials. Normally, when using colloidosomes for drug encapsulation, the latex particles as shell materials need to be mixed with drugs before the assembly process. However, this procedure may cause aggregation of latex particles, thereby resulting in disordered assembled shells or a low loading efficiency. Herein, we propose a three-fluid nozzle spray drying process to efficiently assemble latex particles of P(styrene (St)-co-butyl acrylate (BA)) into colloidosomes. The three-fluid nozzle spray drying equipment allows for the preparation for drug encapsulation without advance mixing of drug and shell materials. This strategy enables the construction of colloidosomes with uniform and controllable pores and the loading of functional materials. The effects of the compressed air flow rate, inlet temperature, feed rate, and solid content were explored, revealing the formation mechanism of colloidosomes during the spray drying process. Doxycycline hydrochloride (DH) was encapsulated in colloidosomes for controllable release, and the sustained release time is up to 100 h. The release rate can be adjusted by varying the glass transition temperature (Tg) and size of latex particles. Furthermore, Fe3O4 nanoparticle (NP)-loaded colloidosomes were constructed by this strategy. The magnetic response intensity of colloidosomes can be modulated by varying the amount of Fe3O4 NPs. The anticancer drug encapsulation and loading of other functional particles were also explored to expand applications.

The use of microtechnology’s in the construction of water aeration installations

Water aeration systems are highly efficient if the dispersion of air in the water is carried out in a controlled and uniform manner. The use of fine bubble generators ensures this and in addition, creates a small loss of pressure when air passes through them. The paper demonstrates that producing as few air bubbles as possible leads to a more efficient aeration process. Two water aeration installations are compared:- The first has a perforated plate with 152 orifices Ø 0.1 mm;- The second has four perforated plates, each with 113 orifices Ø 0.05 mm;Both installations are successively supplied with the same flow rate of compressed air, at the same temperature and at the same initial dissolved oxygen concentration in the water.

EXPERIMENTAL VALIDATION OF PARAMETERS OF HEAVY GRAVITY PNEUMATIC HAMMERS FOR CASING PIPE RAMMING IN SOIL

Vertical penetration of steel pipes with a diameter of 530-1420 mm and to 100-150 m long in soil requires high blow energy (10-100 kJ). Design of the percussion machines using the available pneumatic hammers is constrained due to the high flow rate of an energy source required. It is of the current concern to design an air-driven percussive tool capable to ensure high blow energy at low flow rate of compressed air. This study describes the testing data of a breadboard model of a new gravity pneumatic hammer. The operating mode of the model hammer is studied, and the blow energies, blow frequencies and compressed air flow rates are evaluated as functions of air pressure in the main line. The tests proved stability of cycling operation of the model tool at the high blow energy and low flow rate of the energy source at the main line pressure of 0.36-0.77 MPa. Using the dynamic similarity criteria, the standard sizes of heavy pneumatic hammers are developed, their blow energy and air flow rate are determined, and the efficiency is evaluated.

Effect of elastic valve characteristics on pneumatic impact ring machine capacity

The paper presents a case-study of the effect exerted by a ring-shaped elastic valve as a promising lock-and-control element of air distribution on the performance of a pneumatic impact ring machine. The design model of the machine is presented. The authors determine the blow energy and frequency of the machine, as well as the compressed air flow rate versus the preload of the valve and the elasticity modulus of the valve material. The recommendations on design of the elastic air distribution elements for pneumatic percussion machines subject to their operational conditions are given.

Dynamics of gravity-type pneumatic percussion machine for drain hole drilling

The author presents and justifies a construction diagram of a gravity-type pneumatic percussion machine for drain hole drilling with efficient penetration of casing in soil. The working cycle parameters of the machine, efficient design variables, as well as the blow energy, blow frequency and compressed air flow rate depending on the line pressure are determined by the numerical modeling. The weight, size and dynamics of the gravity-type machine are compared with the known analogous facilities.

Rapid Prototyping of Pneumatic Directional Control Valves.

The main objective of the study was to design a pneumatic directional control valve for controlling pneumatic drives and produce it using a rapid prototyping technique. As the basic design assumption was to achieve high performance through a high flow rate and a low pressure drop, it was necessary to determine two flow parameters: the sonic conductance and the critical pressure ratio. The flow rate of compressed air and the diameters of the pneumatic conduits and fittings are important as they affect the rate of travel of the pneumatic cylinder piston. The 3D solid model of the directional control valve, developed in a CAD program, was used to simulate and optimize the flow rate. The analysis was performed by means of ANSYS CFX, a computational flow dynamics program. The main elements of the valve, i.e., the spool and the body, were produced using the PolyJet Matrix technology. The prototype was tested experimentally to determine the nominal flow-rate, calculate the flow parameters in accordance with the ISO 6358-1989 standard and compare them with the CFD simulation data. The simulation results showed very good agreement with the measurement data. The CFD analysis of the 3D solid model enabled us to optimize the flow of compressed air through the valve. The rapid prototyping method was found to be suitable to produce a fully functional directional control valve, which was confirmed through measurements at a test stand. The attempt to combine rapid prototyping used to fabricate pneumatic directional control valves with CFD used to simulate their operation was successful. The study shows that it is possible to design and construct a fully functional directional control valve characterized by high efficiency, high performance and a small pressure loss in a very short time and at a very low cost, which makes rapid prototyping superior to conventional methods of prototype making.

Study on Spray Evaporation Treatment of Desulfurization Wastewater

Limestone-gypsum wet flue gas desulfurization (WFGD) often produces a certain amount of wastewater with complex water quality and heavy metal pollution which should be treated properly before release. Spaying the desulfurization wastewater into flue duct and using exhausted flue gas heat for evaporation is a promising and economical technology for achieving zero wastewater discharge in thermal power plant. To enable a more in-depth understanding on evaporation of FGD wastewater spray, a visual wind tunnel test rig based on the atomized droplet laser measuring system was built to reveal the impact factors on droplet thermal-fluid behavior. The dominant impact factors such as compressed air pressure and flow rate in air-blast spray nozzle, hot air temperature and velocity in the evaporation tunnel were analyzed to discuss the droplet size distribution and evaporation performance through alternating operate condition. A discrete mathematical model that combines both Eulerian and Lagrangian framework was established to validate the experiment result. It is concluded that introducing high pressure compressed air into the nozzle can contribute to the dispersion of droplets and enhance the evaporation rate. Proper flow rate in spray nozzle is required to avoid incomplete droplets evaporation. Air temperature and velocity in the evaporation tunnel apply positive impact on droplet size distribution and evaporation performance. Numerical simulation results of both dominant factors impact on evaporation behavior and total evaporation rate showed consistency with the experimental outcome.

Non-linear regression approach to ROP predicted in Geothermal well aerated-drilling at Field X, South Sumatera, Indonesia

Rate of penetration is one of the most significant drilling parameters for optimizing the cost of drilling geothermal wells. Many drilling variables affect the rate of penetration. Several correlations have been introduced to predict rate of penetration by involving some of the variables. In this study, a new empirical correlation based on an optimized nonlinear regression model was developed to predict ROP. Several drilling variables i.e. weight on bit, rotation-per minute, compressed air flowrate, true vertical depth, hole diameter, and foam flowrate were included into the correlation. SPSS (Statistical Product and Service Solutions) Software was applied to generate eight equations. The most appropriate equation was selected by comparing the calculated and measured ROP. The selected equation has average percentage difference of 14.6%. In addition, the procedure can be applied to estimate the effect of drilling variables on the accuracy of the model.

Design, Fabrication and Analysis of Bladeless Turbine

A bladeless turbine is capable of using the exhaust gas energy adiabatically by converting most of its energy into shaft power. This bladeless turbine is widely known as Boundary-layer turbine or Cohesion-type turbine. The fundamental physics behind the working of the bladeless turbine is boundary layer effect; boundary layer is the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant. The heat energy that is being wasted as exhaust in a four-stroke engine can be utilized by using a bladeless turbine which is capable of converting a fast-moving fluid (exhaust gas) to shaft work. This shaft work can be used for various applications like to run an alternator or a compressor. The prototype model of bladeless Turbine has been designed and tested with different experiments were made under varying mass air flow rate of compressed air.

Process optimization of spray-dried Moldavian balm (Dracocephalum moldavica L.) extract powder.

The present study was aimed to develop the powder from Moldavian balm extract using a spray dryer to preserve the valuable phytochemicals such as hydroxycinnamic acid and flavonoids. In order to produce optimum Moldavian balm spray‐dried powder, response surface methodology was applied. The inlet air temperature (120–180°C), compressed airflow rate (5–10 L/min), and carriers’ concentration (10%–30%) were kept as independent variables, while moisture content, drying performance, porosity, total phenol content, total flavonoid content, and antioxidant activity were selected as responses. The process was optimized with inlet air temperature of 140.36°C, compressed airflow rate of 9.13 L/min and carriers’ concentration of 18%, resulting in powder with moisture content of 7.68%, drying performance of 62.52%, porosity of 76.4%, total phenol content of 6.295 mg GAE/g, total flavonoid content of 0.378 mg QUE/g, and antioxidant activity of 51.78%. The optimized process led to attain the powder having significantly better phytochemical properties compared with others.

Practical aspects in modeling the air conveying modes of small–piece food products

A mathematical and physical model of the critical pneumatic conveying modes has been developed to ensure the calculation and construction of pneumatic product pipelines of continuous operation. The model takes into consideration the technological conditions of gas suspension movement; the laws of movement of individual fine particles, accounting for their impact interaction and decompression, as well as the actual boundary conditions for a food product movement. The parameters of the zone of dynamic destruction of the layer of a small-piece food product by impact airwave were experimentally studied; the results of the calculation have been compared with the experimental data. The process of managing critical pneumatic conveying modes has been theoretically described, based on the proportional elements and feedback (a current loop of 4‒20 mA); the process of destruction of the cluster of products by airwave and controlled decompression has been studied. The process of pneumatic conveying of a small-piece product at the experimental bench system has been examined. As well as the process of moving the material in the product pipeline, which is controlled by compressed air pulses, to maintain the modes of operation. The following has been established: pressure losses caused by the movement of clean air; additional pressure losses resulting from the movement of the material; the loss of pressure required for transporting in a suspended state on a vertical stretch. A model has been developed to calculate the coordinates of a product particle when it collides with the inner surface of the product pipeline, as well as a change in its kinematic characteristics. The developed model makes it possible to determine the rational modes of pneumatic conveying and possible energy costs in the processing of various small-piece materials. The rational pneumatic conveying regimes have been determined, as well as possible energy costs in the processing of small-piece materials. As the time of supplying compressed air in the product pipeline increases, the number of product particles reaches a maximum in the range of 0.1...0.2 s. The compressed air flow rate, depending on the value of inlet mainline pressure P (0.1…0.3 MPa), is 80…160 (Nl/min). A general approach to the modeling of pneumatic conveying systems has been proposed

Study on Airflow Migration and Rock Dust Pollution Behavior in TBM Construction Tunnel

When tunnel boring machines (TBMs) are used to construct tunnels, large quantities of rock dust are produced, affecting the working environment of construction personnel. To explore ways to improve the air quality in tunnels, this study employed a numerical simulation to investigate controlling rock dust via tunnel ventilation systems. The results showed that when the secondary compressed airflow rate (Q2) was set to 4–11 m3/s, the rock dust produced could be controlled within a range of 77.2 m from the tunnel face. When Q2 = 8 m3/s, the rock dust diffusion distance (LD) reached a minimum of 42.7 m, and the rock dust concentration around the operating region (CW) was approximately 30.1 mg/m3. To explore the further enhancement of dust suppression performance in a tunnel, a numerical simulation was conducted on rock dust diffusion in the tunnel when Q2 was fixed but the exhaust airflow rate (QC) was set to different values. According to the numerical simulation results, when QC = 15 m3/s, the rock dust produced could be effectively controlled at the front of the tunnel with a length of 14.6 m, i.e., the rock dust could be most effectively suppressed.

Justification of pneumatic percussion machine performance in formation of main cracks from holes in natural stone

The study focuses on a percussive machine for directional fracturing of natural stone. The impact machine forces a rock-breaking tool to make a hole and penetrate it. Stone is propped as a result, and a main crack is formed finally along the row of holes. For the gravity-type pneumatic percussion machines, the circuit design is justified, and the numerical analysis of structural constants and performance of the machines is carried out based on the modeled dynamics of basic units. The operating cycle of the machine was evaluated by blow energy, blow frequency and compressed air flow rate. It is found that the operating cycle of the gravity-type pneumatic percussion machine with elastic valve ensures effective consumption of compressed air and high energy of impact. The numerical modeling data are proved by experimental results at the Institute of Mining, SB RAS.

Characterization of a micro thermal cavity receiver – Experimental and analytical investigation

The objective of this work is to characterize the optical and thermal performance of a micro-scale cylindrical cavity solar receiver for the Brayton gas power cycle at various solar radiation levels through experimental and analytical investigation. A thermal receiver consisting of a 300 mm deep and 200 mm diameter cylindrical cavity equipped with an 8 mm diameter helical copper tube was studied. An advanced ray-tracing technique using OptisWorks software was used to predict the distribution of solar radiation inside the cavity. Also, computational fluid dynamics simulations were carried out using ANSYS CFD software to predict the temperature distributions of the coil surface and the compressed air outlet temperature. Having satisfying conformity between the numerical and the experimental results, the current results demonstrated that a competent flux and temperature distributions were directed on the receiver’s tube. Moreover, an outlet temperature up to 70 °C, based on the available compressed air flow rate. This point leads to the probability of operating a micro-scale dish concentrator for Concentrated Solar Power in a domestic application. The results of a parametric study indicated that a cavity’s receiver depth and width of 180 mm and 240 mm give the best thermal operation.