Development of simplified models for the freeze-drying process and investigation of the optimal operating conditions

2008 ◽  
Vol 86 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Salvatore A. Velardi ◽  
Antonello A. Barresi
Keyword(s):  
Freeze Drying ◽  
Operating Conditions ◽  
Drying Process ◽  
Simplified Models ◽  
Optimal Operating

A Scheme to Assist in the Evaluation of Tenter Frame Dryer Performance

1979 ◽  
Vol 101 (1) ◽  
pp. 80-84 ◽  
Author(s):  
W. F. Beckwith ◽  
J. N. Beard
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Operating Conditions ◽  
Temperature Profiles ◽  
Simulation Studies ◽  
Drying Process ◽  
Optimal Operating

One of the textile industry’s largest consumers of energy is the tenter frame dryer. To assist the industry in operating these dryers efficiently, a mathematical model which simulates the drying process and a scheme to solve for the parameters in the differential equations of the model have been developed and are presented in this paper. Temperature profiles predicted from the model are compared with profiles measured on commercial dryers. Also dryer simulation studies to elucidate optimal operating conditions are discussed.

scholarly journals Energy analysis of an ultrasound-assisted atmospheric freeze-drying process for food

2018 ◽  
Author(s):  
Juan A. Cárcel ◽  
Daniele Merone ◽  
Domenico Colucci ◽  
Davide Fissore ◽  
Neus Sanjuán
Keyword(s):  
Energy Consumption ◽  
Freeze Drying ◽  
Operating Conditions ◽  
Model Parameters ◽  
Dehydration Process ◽  
Drying Process ◽  
Water Diffusivity ◽  
Ultrasound Assisted ◽  
The Impact ◽  
Air Dryer

Power ultrasounds have been proposed and extensively investigated as an effective way to speed up the atmospheric freeze-drying process, thus making this dehydration process attractive from an industrial viewpoint. Nevertheless, a rigorous investigation on the impact of power ultrasounds on the energy consumed by the process is still missing. This paper aims to investigate this issue. Apple, carrot and eggplant were chosen as representative products with different textures and water content. A mathematical model of the whole plant required to carry out the atmospheric ultrasound-assisted drying process was developed to assess the effect of the operating conditions on the energy consumption. Model parameters were tuned on the basis of the results obtained in a pilot-scale unit, thus allowing the use of the model to simulate the whole industrial dehydration process. Life Cycle Assessment (LCA) was used as a complementary tool to gain an insight on the environmental impact of the process. Results showed that due to differences in the water diffusivity for the analyzed products, substantial differences in energy consumption can be highlighted. In fact, when the water diffusivity increases, the capacity of the material to move water away also increases and the time to obtain a dry product is thus reduced. Moreover, although the use of ultrasound causes an increase in the hourly energy consumption (kWh·h-1), the total energy consumption of the whole process (kWh) is lower, since the total operation time is reduced. The LCA results highlighted the cooling system as the most critical stage for all the impact categories studied. This is mainly due to the use of ethylene glycol and R-404 in the refrigeration cycle. Nevertheless, when dehydrating low porosity products the energy consumption of the air dryer increased and this stage becomes, the most critical from an environmental point of viewKeywords: atmospheric freeze-drying, ultrasounds, process modeling, LCA.

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

Studies of microbial acclimation to hard chemicals on the basis of respiratory quinone profiles and kinetic analyses

1996 ◽  
Vol 34 (5-6) ◽  
pp. 249-256 ◽  
Author(s):  
Hong-Ying Hu ◽  
Mamie Nozawa ◽  
Koichi Fujie ◽  
Tsuyoshi Makabe ◽  
Kohei Urano
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Population Dynamics ◽  
Volatile Substance ◽  
Operating Conditions ◽  
Biological Wastewater Treatment ◽  
Basic Information ◽  
Optimal Operating ◽  
Respiratory Quinone ◽  
Treatment Processes ◽  
Quinone Profile

The population dynamics of microbes in the biological wastewater treatment processes such as a submerged biofilter was investigated to obtain basic information to determine the optimal operating conditions. The effects of coexistence of biodegradable substances such as glucose and peptone on the acclimation of microbes in the biofilm to hard chemicals such as acrylonitrile (AN), which is poorly biodegradable and a volatile substance, was investigated on the basis of the respiratory quinone profile. Kinetic study of the removal of AN in the course of acclimation of microbes was investigated using a laboratory-scale submerged biofilter as well. It was ascertained that the acclimation of the microbes to AN was accelerated by coexistence of biodegradable substances, and the microbial phase after acclimation differed from those with the coexistence of glucose and peptone. The quinone profiles in the acclimation showed that Brevibacterium sp. and Pseudomonas aeruginosa, of which the predominant quinone of the respiratory chain is menaquinone-8(H2) and ubiquinone-9, respectively, multiplied selectively in the acclimation course without and with the coexistence of glucose and peptone, respectively. It was also made clear that there were few kinds and number of protozoa and metazoa in the biofilter treating the wastewater containing AN.

scholarly journals Evaporator Optimization of Refrigerator Systems Using Quality Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 555
Author(s):  
Sangkyung Na ◽  
Sanghun Song ◽  
Seunghyuk Lee ◽  
Jehwan Lee ◽  
Hyun Kim ◽  
...  
Keyword(s):  
Power Consumption ◽  
Operating Time ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Quality Analysis ◽  
Lubricating Oil ◽  
Optimal Operating ◽  
Compressor Piston ◽  
Refrigerator Temperature ◽  
Visualization Experiments

In this study, evaporator optimization, via both experimental and simulation methods was conducted. To evaluate the evaporator performance, under the optimal system, the compressor operating time and the effects of oil on the refrigerator system were studied. If the temperature of the refrigerator chamber reaches the setting value, the compressor stops working and it leads to the temperature of the refrigerator chamber slowly increasing, due to the heat transfer to the ambient. When the refrigerator temperature is out of the setting range, the compressor works again, and the refrigerator repeats this process until the end of its life. These on/off period can be controlled through the compressor piston movement. To determine the optimal compressor operating conditions, experiments of monthly power consumption were conducted under various compressor working times and the lowest power consumption conditions was determined when the compressor worked continuously. Lubricating oil, the refrigerator system, using oil, also influenced the system performance. To evaluate the effect of oil, oil eliminated and oil systems were compared based on cooling capacity and power consumption. The cooling capacity of the oil eliminated system was 2.6% higher and the power consumption was 3.6% lower than that of the oil system. After determining the optimal operating conditions of the refrigerator system, visualization experiments and simulations were conducted to decide the optimal evaporator and the conventional evaporator size can be reduced by approximately 2.9%.

scholarly journals Chemical–Electrochemical Process Concept for Lead Recovery from Waste Cathode Ray Tube Glass

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1546
Author(s):  
Árpád Imre-Lucaci ◽  
Melinda Fogarasi ◽  
Florica Imre-Lucaci ◽  
Szabolcs Fogarasi
Keyword(s):  
Flow Rate ◽  
Current Density ◽  
Complete Recovery ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
General Effect ◽  
Optimal Operating ◽  
Recirculation Flow ◽  
Lead Recovery ◽  
Cathode Ray Tube

This paper presents a novel approach for the recovery of lead from waste cathode-ray tube (CRT) glass by applying a combined chemical-electrochemical process which allows the simultaneous recovery of Pb from waste CRT glass and electrochemical regeneration of the leaching agent. The optimal operating conditions were identified based on the influence of leaching agent concentration, recirculation flow rate and current density on the main technical performance indicators. The experimental results demonstrate that the process is the most efficient at 0.6 M acetic acid concentration, flow rate of 45 mL/min and current density of 4 mA/cm2. The mass balance data corresponding to the recycling of 10 kg/h waste CRT glass in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices (GEIs), obtained through the Biwer Heinzle method for the input and output streams of the process, indicate that the developed recovery process not only achieve a complete recovery of lead but it is eco-friendly as well.

scholarly journals Strengthening of Porcine Plasma Protein Superabsorbent Materials through a Solubilization-Freeze-Drying Process

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 772
Author(s):  
Estefanía Álvarez-Castillo ◽  
Carlos Bengoechea ◽  
Antonio Guerrero
Keyword(s):  
Water Uptake ◽  
Plasma Protein ◽  
Freeze Drying ◽  
Meat Industry ◽  
Drying Process ◽  
Uptake Capacity ◽  
Water Uptake Capacity ◽  
Protein Flour ◽  
Hydrophilic Materials ◽  
By Products

The replacement of common acrylic derivatives by biodegradable materials in the formulation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materials based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze-drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.

Experimental Investigation on the Performance of a Formic Acid Electrolyte-Direct Methanol Fuel Cell

2013 ◽  
Vol 11 (2) ◽  
Author(s):  
David Ouellette ◽  
Cynthia Ann Cruickshank ◽  
Edgar Matida
Keyword(s):  
Fuel Cell ◽  
Formic Acid ◽  
Power Output ◽  
Direct Methanol Fuel Cell ◽  
Operating Conditions ◽  
Portable Devices ◽  
Acid Electrolyte ◽  
Optimal Operating ◽  
Direct Methanol ◽  
Methanol Fuel Cell

The performance of a new methanol fuel cell that utilizes a liquid formic acid electrolyte, named the formic acid electrolyte-direct methanol fuel cell (FAE-DMFC) is experimentally investigated. This fuel cell type has the capability of recycling/washing away methanol, without the need of methanol-electrolyte separation. Three fuel cell configurations were examined: a flowing electrolyte and two circulating electrolyte configurations. From these three configurations, the flowing electrolyte and the circulating electrolyte, with the electrolyte outlet routed to the anode inlet, provided the most stable power output, where minimal decay in performance and less than 3% and 5.6% variation in power output were observed in the respective configurations. The flowing electrolyte configuration also yielded the greatest power output by as much as 34%. Furthermore, for the flowing electrolyte configuration, several key operating conditions were experimentally tested to determine the optimal operating points. It was found that an inlet concentration of 2.2 M methanol and 6.5 M formic acid, as along with a cell temperature of 52.8 °C provided the best performance. Since this fuel cell has a low optimal operating temperature, this fuel cell has potential applications for handheld portable devices.

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