Mass Flow Rate Of Dry Air Research Articles

Synthesis of solid NMC622 particles by spray drying, post-annealing and lithiation

Layered lithium-nickel-manganese-cobalt oxide (NMC) cathode materials are widely used in Li-ion batteries that require high energy densities, such as those used in plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs). Here we studied the synthesis of NMC622 particles by spray pyrolysis, which is a simple one-step process for production of spherical particles. However, synthesising NMC powder using spray pyrolysis has a tendency to produce hollow NMC particles. To gain insight into the mechanism behind the formation of the hollow particles, one dimensional numerical simulation of the physical and chemical phenomena taking place during spray drying were carried out. The effects of several process parameters, including drying air temperature, drying air mass flow rate, and liquid feed mass flow rate, on the evaporation and particle formation process were studied. The increased evaporation rate at higher temperatures was found to result in crust formation on the droplet surface during the particle formation, and thus, in lower solid volume fractions in the dried particles. However, by optimizing the process parameters production of solid NMC622 sulphate particles by spray drying was achieved. The produced NMC622 sulphate particles were then oxidised and lithiated in air at 850 °C via the conventional thermal treatment process. Four lithium precursors, LiOH, Li2CO3, Li2SO4 and LiNO3, were tested for the lithiation of the oxidized NMC particles. The degree of lithiation and the crystalline phase of the powders were determined using ICP-OES and XRD, respectively.

Drying characteristics, energetic and exergetic investigation during mixed-mode solar drying of pineapple slices at varied air mass flow rates

Present work is focused on the assessment of energy and exergy flow in a mixed-mode solar dryer during the drying of pineapple slices by utilizing first and second law of thermodynamics. Moreover, drying kinetics and effective moisture diffusivity with shrinkage correction were also investigated at natural convection (NC) and forced convection (FC) conditions. The initial moisture of pineapple slices (90%, wb) was reduced to 29.66, 23.06, 24.05 and 19.68% (wb) in 6.5 h under NC, air mass flow rates of 0.006, 0.01 and 0.015 kg/s, respectively. Results revealed that diffusivity determined by assuming negligible shrinkage demonstrated 3.5–5.3 times overestimation than shrinkage consideration. Energy analysis exhibited that about 55–78% of total input solar energy constituted thermal losses from the absorber plate. Remarkably, an increase of air mass flow rate caused an augmentation in useful heat gain by air and a simultaneous reduction in thermal losses from collector along with its efficiency improvement. Exergetic investigation of dryer identified that the exergy efficiency of the solar collector and drying chamber was positively influenced by increasing air velocity. Furthermore, exergy efficiency of the dryer for NC and drying air mass flow rate of 0.006, 0.01 kg/s was 85.45%, 46.15%, and 18.88% lesser than 0.015 kg/s, respectively.

Simulation on vapour compression heat pump system for rough rice drying

In this study, a simulation of a vapor compression heat pump system for bed drying of rough rice have been carried out for various thicknesses in the range of 20-50 cm and various drying air mass flow rates in the range of 0.06 - 0.22 kg/s-m2. The modelling used was grouped into two parts, i.e. the determination of temperature and humidity of the air coming out of the heat pump and the drying process of the rough rice using these air conditions. Parameters related to flow rate and energy were expressed in units of cross-sectional area of the drying bed. Simulation results showed significant differences in drying time and temperature for various thicknesses and air mass flow rates but their energy consumptions were similar. Under these conditions the drying temperature and drying time obtained ranged between 34-45°C and 8-15 hours, respectively while the specific energy consumption was relatively low i.e. in the range of 1.07-1.36 MJ/kg of evaporated water for all the scenarios tested. The specific drying air mass flow rate of 0.3 and 0.5 kg/s/m3 did not provide significant differences in specific energy consumption. For the field applications, the selection of conditions for thickness and the appropriate air mass flow rate will depend on the user preference including the ease of mixing, drying time or energy consumption.

Effect of air mass flow rate on the performance of a mixed-mode active solar crop dryer with a transpired air heater

A mixed-mode active solar crop dryer with a transpired solar air heater was developed and tested under Makurdi, Nigeria prevailing weather conditions. The transpired solar collected was tilted at 17.73° (latitude of Makurdi + 10), east. Experiments were conducted at five levels of drying air mass flow rate. Final moisture content of maize was reduced to a range of 11.75–16.87% (d.b.) within six hours from an initial moisture content range of 47.16–51.14% (d.b.). From the drying curves, the grain samples are dried faster at the air mass flow rate of 0.038 kg/s. The collector and drying efficiencies range between 65.20 −71.77% and 55.3–82.2%, respectively. The highest drying efficiency of 82.2% was recorded at air mass flow rate of 0.038 kg/s and the minimum efficiency of 55.3 was recorded at air mass flow rate of 0.026 kg/s. The dryer can replace conventional dryers.

Quantitative assesment of the improvement of the drying process by increasing the turbulence level

The drying process of vegetable species is a widely used technique for food conservation. The process requires large amounts of energy and it is responsible for the emission of pollutants to the environment. Therefore, many investigations have been made in order to improve the energy aspects of the process. It is very common that the effect of temperature and drying air mass-flow rate on the drying process are included in research but the effect of the turbulence level has not been studied yet. In this paper, the effect of the drying air turbulence level, temperature and mass-flow rate in the drying time, efficiency and energy consumption involved in the drying process of three types of chilies are studied. Under the conditions studied the turbulence level is the most influential factor in the drying process, followed by drying temperature. Also, the energy invested in increasing the turbulence level is very advantageous.

Fish oil microencapsulation as influenced by spray dryer operational variables

SummaryThe effects of spray‐drying air temperature, aspirator rate (drying air mass flow rate), peristaltic pump rate (feed mass flow rate) and spraying air mass flow rate on microencapsulation properties of fish oil including moisture content, particle size, bulk density, encapsulation efficiency and peroxide were investigated. The process was carried out on a mini spray dryer, and skim milk powder was used as the encapsulating wall material. Results indicated that increasing inlet air temperature increased the particle size, encapsulation efficiency and peroxide value but decreased the bulk density and moisture content of product. Increasing aspirator rate resulted in increased particle size and peroxide value but decreased the moisture content and bulk density. Increase in feed mass flow rate increased the moisture content, particle size, bulk density and peroxide value but decreased the encapsulation efficiency of microcapsules. The encapsulation efficiency and bulk density increased with the increasing aspirator rate but moisture content, particle size and peroxide value decreased.

Influence of spray dryer parameters on exergetic performance of microencapsulation processs

Exergy analysis of fish oil microencapsulation process by spray drying was carried out. The process was performed on a mini–spray dryer and skim milk powder was used as the coating wall material. The drying experiments were conducted to find the effects of inlet drying air temperature, drying air mass flow rate, feed mass flow rate, and spraying gas mass flow rate on inlet exergy, outlet exergy, exergy destruction, exergy loss, entropy generation, exergy efficiency, and improvement potential. Results indicated that the magnitude of parameters studied depend on the operational conditions of dryer.

EXERGETIC ASSESSMENT OF DRYING OF MINT LEAVES IN A HEAT PUMP DRYER

ABSTRACT This article deals with the exergy analysis of a single layer drying process of mint leaves in a ground source heat pump tray dryer, which was designed and constructed in the Solar Energy Institute, Ege University, Izmir, Turkey. The drying process was realized at three various drying air temperatures of 40, 45 and 50C, and mass flow rate from 0.01 to 0.05 kg/s at a constant relative humidity of 16%. The effects of temperatures and mass flow rates on the exergy losses, exergy efficiencies and improvement potentials of the drying process were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 50C and a drying air mass flow rate of 0.05 kg/s. The exergy efficiency values were obtained to vary from 76.03 to 97.24% at drying air temperatures of 40–50C with drying air mass flow rates of 0.01–0.05 kg/s. PRACTICAL APPLICATIONSThis study is useful for not only producers of dry mints, but also for all dry herbs. It may be successfully used in the design and performance evaluation of heat pump dryers.

Exergetic evaluation of drying of laurel leaves in a vertical ground-source heat pump drying cabinet

This paper is concerned with the exergy analysis of the single layer drying process of laurel leaves in a ground-source heat pump drying cabinet, which was designed and constructed in the Solar Energy Institute, Ege University, Izmir, Turkey. The effects of drying air temperature on exergy losses, exergy efficiencies and exergetic improvement potential of the drying process are investigated. The results have indicated that exergy efficiencies of the dryer increase with rising the drying air temperature. Moreover, the laurel leaves are sufficiently dried at the temperatures ranging from 40 to 50°C with relative humidities varying from 16 to 19% and a drying air velocity of 0.5 m s−1 during the drying period of 9 h. The exergy efficiency values are obtained to range from 81.35 to 87.48% based on the inflow, outflow and loss of exergy, and 9.11 to 15.48% based on the product/fuel basis between the same drying air temperatures with a drying air mass flow rate of 0.12 kg s−1. Copyright © 2006 John Wiley & Sons, Ltd.

Performance analysis of drying of green olive in a tray dryer

This paper deals with the performance evaluation of a single layer drying process of green olives in a tray dryer using exergy analysis method. Green olive was used as the test material being dried. Drying process was realized at four different drying air temperatures (40, 50, 60 and 70 °C) and a constant relative humidity of 15%. The effects of temperatures and mass flow rates were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 70 °C and a drying air mass flow rate of 0.015 kg/s with 0.0004 kg/s of olive. The exergy efficiency values were found to be in the range of 68.65%–91.79% from 40 °C to 70 °C with drying air mass flow rates of 0.01 kg/s–0.015 kg/s.