Drying of wet agglomerates in a continuous fluid bed: Influence of residence time, air temperature and air-flow rate on the drying kinetics and the amount of oversize particles

2007 ◽  
Vol 62 (1-2) ◽  
pp. 463-470 ◽  
Author(s):  
Stefan Palzer
Keyword(s):  
Residence Time ◽  
Air Temperature ◽  
Flow Rate ◽  
Air Flow ◽  
Drying Kinetics ◽  
Air Flow Rate ◽  
Fluid Bed

Optimization of Drying Kinetics and Quality Parameters of Broccoli Florets

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Andrea V Mahn ◽  
Paola Antoine ◽  
Alejandro Reyes
Keyword(s):  
Antioxidant Activity ◽  
Air Temperature ◽  
Flow Rate ◽  
Air Flow ◽  
Radical Scavenging ◽  
Particle Diameter ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Air Flow Rate ◽  
Drying Time

Drying kinetics of broccoli florets in a tunnel dryer was studied. Effective moisture diffusivity (Deff) and activation energy for moisture diffusion (E0) were estimated. The effect of air temperature, air flow rate and particle size on antioxidant capacity, greenness and texture were calculated through a 23 factorial design. Air flow rate and temperature significantly affected drying time. Deff fluctuated between 2.82 x 10-10 and 2.00 x 10-9 (m2/s), and E0 was around 42 KJ/mol, agreeing with values reported in literature. The maximum antioxidant activity was obtained at 60°C, air flow rate of 4 m/s and 1.5 cm particle diameter, resulting in a 70 percent reduction in free radical scavenging ability and a 29 percent increase in total reductive capability. Air temperature had significant effect on greenness, and air flow rate significantly affected texture. The optimization of convective drying of broccoli allows maximizing antioxidant activity and minimizing cost by saving energy and time.

Effect of Blanching and Air Flow Rate on Turmeric Drying

2006 ◽  
Vol 12 (4) ◽  
pp. 315-323 ◽  
Author(s):  
M. Blasco ◽  
J. V. García-Pérez ◽  
J. Bon ◽  
J. E. Carreres ◽  
A. Mulet
Keyword(s):  
Diffusion Model ◽  
Flow Rate ◽  
Air Flow ◽  
Internal Resistance ◽  
Empirical Models ◽  
Drying Kinetics ◽  
Air Flow Rate ◽  
Air Drying ◽  
Control Zone ◽  
Different Temperatures

Turmeric processing involves two main steps, blanching and drying. Blanching is a common step in the traditional processing of rhizomes, and hot air drying is an alternative to traditional solar drying. For this study, drying kinetics were performed at different air flow rates (0.2, 0.5, 0.7, 1.2, 2.1, 2.6, 3 and 4m/s) to determine the effect of air flow on the process. To examine the blanching effect, drying kinetics were carried out with blanched and unblanched rhizomes at different temperatures (60, 70, 80, 90 and 100ºC). A diffusion model and two empirical models (Weibull and Peleg) were used to describe mass transfer during drying. The effect of air flow rate on external resistance was observed, and the air velocity transition zone between the external and internal resistance control zone was identified (1–2m/s). Blanching previous to drying increased the process rate at all the temperatures tested, although its effect was reduced when the air drying temperature increased. Empirical models fitted better drying kinetics than the diffusion model, however, the diffusion model provides valuable information about the phenomenon of water removal and scaling up.

Utilization of Wet Forest Biomass as both the Feedstock and Electricity Source for an Integrated Biochar Production System

2018 ◽  
Vol 34 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Anthony Eggink ◽  
Kyle Palmer ◽  
Mark Severy ◽  
Dave Carter ◽  
Arne Jacobson
Keyword(s):  
Heat Exchanger ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Integrated System ◽  
Low Flow ◽  
Production Plant ◽  
Production Operation ◽  
Air Flow Rate ◽  
Process Heat

Abstract. A belt dryer and gasifier generator set were integrated into a biochar production plant to use process heat to dry biomass feedstock from forest residuals and to provide electric power to the plant using a side stream of dried biomass. Experiments were conducted to characterize the dryer throughput and drying capacity using process heat from a stack heat exchanger attached to the biochar machine flare. A matrix of tests was conducted at high and low flow rates for both the heat exchanger air flow rate (which varied the temperature and heat input to the dryer) and the residence time of feedstock in the belt dryer. Mean feedstock input moisture during dryer characterization was 45% and the mean moisture after exiting the dryer was 27%. The optimal test condition, providing the greatest water removal rate, was determined to have high air flow rate through the heat exchanger and short dryer residence time. This condition was used to demonstrate the integrated system for an 8-h production day. The integrated system dried incoming feedstock from 36% to 22% with a dryer throughput rate of 495 kg h-1 w.b. and an evaporation rate of 88.8 kg h-1, providing the necessary dry feedstock for the 20-kW gasifier generator set and the biochar machine, which produced 75 kg h-1 of biochar. This system required the operational effort of 0.92 labor hours per production hour. Results from this demonstration indicate that the integrated system provides key benefits in a biochar production operation including greater control of feedstock drying and the ability to operate without an external (non-biomass) source of fuel for electricity generation. Keywords: Biochar, Biomass, Biomass drying, Forest residuals, Gasification, Pyrolysis.

Effects of air temperature and air flow rate control on the tipburn occurrence of leaf lettuce in a closed-type plant factory system

2013 ◽  
Vol 54 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Jun Gu Lee ◽  
Chang Sun Choi ◽  
Yoon Ah Jang ◽  
Suk Woo Jang ◽  
Sang Gyu Lee ◽  
...  
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Rate Control ◽  
Air Flow ◽  
Air Flow Rate ◽  
Closed Type ◽  
Plant Factory ◽  
Flow Rate Control ◽  
Leaf Lettuce

Effect of Process Parameters on Characteristics of Spray-Dried Hydroxyapatite Granules

2017 ◽  
Vol 728 ◽  
pp. 341-346 ◽  
Author(s):  
Weeranuch Sukaraseranee ◽  
Sukasem Watcharamaisakul ◽  
Boris Golman ◽  
Jintamai Suwanprateeb
Keyword(s):  
Size Distribution ◽  
Air Temperature ◽  
Flow Rate ◽  
Feed Rate ◽  
Air Flow ◽  
Spherical Shape ◽  
Air Flow Rate ◽  
Uniform Size ◽  
Drying Conditions ◽  
Spray Dried

The effects of drying air temperature and flow rate, spraying air flow rate and slurry feed rate were investigated on the morphology, size distribution, density and flowability of spray-dried hydroxyapatite granules. The granules were of good spherical shape and smooth surface, but low flowability. The granules of uniform size distribution were obtained at high spraying air flow rate and granules of small sizes were collected at high spraying and drying air flow rates, high slurry feed rate and low drying air temperature. Thus, by adjusting the spray drying conditions we can control the granule properties.

Experimental Study of Solar Air Heating System Based on Unglazed Transpired Collector

2011 ◽  
Author(s):  
Lixin Gao ◽  
Hua Bai ◽  
Xiumu Fang
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Flow Rate ◽  
Temperature Rise ◽  
Air Flow ◽  
Heating System ◽  
Airflow Rate ◽  
Air Flow Rate ◽  
Air Heating ◽  
Collector Efficiency

An experimental rig was set up to test the thermal performance of a solar air heating system based on an unglazed transpired collector of 2.5 m2. The experiment was carried out at Harbin Institute of Technology in the city of Harbin, which is located in northeastern China, at latitude 45°41′ N and longitude 126°37′ E. The tests were spread over a number of days, in which the 4-day experimental data within the period were selected as the sample for analysis. Experimental results show that solar collector’s surface temperature and exit air temperature increase with increasing solar irradiation. The influence of ambient temperature on surface temperature and exit temperature is negligible. Temperature rise decreases with increasing air flow rate, while collector efficiency increases with increasing air flow rate. For an air flow rate of 100 m3/h in Test 1, the average air temperature rise and collector efficiency were 28.86°C and 72% respectively; for an air flow rate of 235 m3/h in Test 2, the average air temperature rise and collector efficiency were 11.52°C and 78% respectively. Higher airflow rate tends to operate the collector at lower surface temperature, which results in lower overall heat losses from the collector to the surroundings, therefore increasing airflow rate reduces air temperature rise and enhances the collector efficiency. The average efficiency of the experimental solar air heating system in the 4-day experiment period was 72%, 78%, 61%, and 72% respectively, which are higher than most conventional glazed flat-plate solar air collectors. With better coordination with architectural design at early stage in a project, this building-integrated solar air heating system can be both aesthetically and technically viable.

Effects of Impeller Speed, Atomising Air Flow Rate and Fluidising Temperature in Agitated Fluidised Bed Granulation of Cocoa-Milk Powders

2005 ◽  
Vol 1 (3) ◽  
Author(s):  
Mohd Shamsul Anuar ◽  
Siti Masrinda Tasirin
Keyword(s):  
Moisture Content ◽  
Flow Rate ◽  
Air Flow ◽  
Impeller Speed ◽  
Fluidised Bed ◽  
Air Flow Rate ◽  
Operational Parameters ◽  
Operational Variables ◽  
Fluid Bed ◽  
Fluid Bed Granulation

Mechanically agitated fluid bed granulators with inserted impeller are currently favoured by the industry due to better particle mixing, heat transfer and effective particle growth. However, effects of operational variables such as impeller speed, atomising air flow rate and fluidising temperature on the physical characteristics of the generated granules are still not fully quantified. Scaling-up of industrial fluid bed granulation processes especially in the pharmaceutical industry are done empirically. In this paper, a study is described on the effects of impeller speed, atomising air flow rate and fluidising temperature on the flowability, moisture content, mean particle size and size distribution of the granulated cocoa-milk drink powder in an agitated fluid bed granulation process. Findings showed that when all the values of the three investigated operational parameters were increased, granules with better flowability characteristics, lower moisture content, smaller and more uniformed granules were obtained in the range tested.

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