scholarly journals Progressive freeze concentration of skimmed milk in an agitated vessel: Effect of the coolant temperature and stirring rate on process performance

2018 ◽  
Vol 25 (2) ◽  
pp. 150-159 ◽  
Author(s):  
Isabella de Bona Muñoz ◽  
Ariadna Rubio ◽  
Mónica Blanco ◽  
Mercè Raventós ◽  
Eduard Hernández ◽  
...  
Keyword(s):  
Freezing Point ◽  
Agitation Speed ◽  
Operating Conditions ◽  
Coolant Temperature ◽  
Freeze Concentration ◽  
Mechanical Stirring ◽  
Concentration Technique ◽  
Stirring Rate ◽  
Solids Concentration ◽  
Skimmed Milk

The aim of this study was to investigate the freeze-concentration of skimmed milk by a progressive freeze concentration process. The progressive freeze concentration procedure was performed at three different temperatures (−5, −10, and −15 ℃) and stirring rates (0, 500, and 1000 r/min). The solids concentration was determined and used for calculations of the efficiency of the process, concentrated yield, and experimental results validation. A general linear model was applied to determine the influence of the two factors studied, namely coolant temperature and agitation speed. In all tests, it was possible to concentrated skimmed milk with total solids content higher (P < 0.05) than ultra-high temperature skimmed milk. The highest concentration (P < 0.05) was achieved at low coolant temperature (−15 ℃) and high agitation speed (1000 r/min). The coolant temperature and the stirring rate both had a significant effect (P < 0.05) on the results of efficiency of the process and concentrated yield. Nevertheless, the parameter that showed the most significant effect in our study was the stirring rate. The tests presented a good fit since the root mean square values were below 25%. The freezing point temperatures of the concentrated milk fractions were lower than that of skimmed milk. Finally, the best-operating conditions in our study were achieved using a high coolant temperature (−5 ℃) and high mechanical stirring (1000 r/min), which was also the variable with the lowest (P < 0.05) retention of solids in the ice fraction. In our study, the progressive freeze concentration technique showed promise as an alternative for the dairy industry since it makes the development of new dairy products possible.

Retention of total phenolic content and antioxidant activity in the concentration of broccoli extract by progressive freeze concentration

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Aisyah N. H. Azhar ◽  
Mohanadharshini Panirselvam ◽  
Nurul A. Amran ◽  
Muhammad S. H. Ruslan ◽  
Shafirah Samsuri
Keyword(s):  
Antioxidant Activity ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Low Cost ◽  
Extraction Process ◽  
Coolant Temperature ◽  
Total Phenolic ◽  
Freezing Time ◽  
Freeze Concentration ◽  
Stirring Rate

AbstractA conventional evaporation is known to involve high temperature process which could destroy the heat-sensitive compound in a plant extract. In this study, a green and low-cost alternative concentration technique namely progressive freeze concentration (PFC) has been introduced to concentrate broccoli extract. A stirred cylindrical crystallizer was used to freeze the added solvent (water) in the extraction process. The changes in effective partition constant (K), antioxidant activity (AA) and total phenolic content (TPC) of the extract, were analysed at a different reading of coolant temperature, freezing time and stirring rate. From the findings, it was found that an amount of 0.003180 mg GAE/g of total phenolic content and 86.10% of antioxidant activity were retained through the PFC process at a coolant temperature of −6 °C, freezing time of 45 min and stirring rate of 100. Besides, the lowest K value achieved was 0.08 which outstandingly portrays an efficient PFC process.

Progressive Freeze Concentration of Coconut Water

2014 ◽  
Vol 67 (2) ◽  
Author(s):  
Mazura Jusoh ◽  
Noor Naimah Mohamed Nor ◽  
Zaki Yamani Zakaria
Keyword(s):  
Sugar Content ◽  
Coconut Water ◽  
Coolant Temperature ◽  
K Value ◽  
Initial Concentration ◽  
Freeze Concentration ◽  
Concentration Technique ◽  
The World ◽  
Single Block ◽  
Nutritional Compounds

In order to provide convenience for consumers around the world, it is highly beneficial if the nutritious coconut water (CW) could be concentrated and just easily be added with water for later consumption. A new concentration technique is required to eliminate some parts of the water from the CW while retaining its nutritious and unique aroma. As Progressive Freeze Concentration (PFC) could retain the nutritional compounds, it was applied to concentrate CW and reduce its volume. In PFC system, only a single block of ice is formed as a layer on the cooled surface. A coil stainless steel crystallizer was used as FC unit to investigate the enhancement of sugar content in CW. The effect of initial concentration of CW was then investigated on the performance of the PFC system through the Effective Partition Constant (K) value and increment of sugar content. It was found that low initial concentration and intermediate coolant temperature yielded lower K value and high increment of sugar content. The best K achieved was 0.3101 and the highest increment of sugar content was 53% at initial concentration of 3 %Brix and coolant temperature of 12°C.

Enhancement of Sugar Content through Progressive Freeze Concentration: Effect of Initial Concentration

2014 ◽  
Vol 69 (4) ◽  
Author(s):  
Mazura Jusoh ◽  
Noor Naimah Mohamed Nor ◽  
Nurul Aini Amran ◽  
Shafirah Syamsuri
Keyword(s):  
Stainless Steel ◽  
Sugar Content ◽  
K Value ◽  
Initial Concentration ◽  
Freeze Concentration ◽  
Concentration Technique ◽  
High Sugar Content ◽  
Single Block ◽  
Nutritional Compounds ◽  
The Cost

A new concentration technique is required to eliminate portion of water from coconut water (CW) and reduce the cost of storage, handling and shipping. As Progressive Freeze Concentration (PFC) could retain the nutritional compounds, it was applied to concentrate CW and enhance its sugar content. In PFC system, only a single block of ice is formed as a layer on the cooled surface. A coil stainless steel crystallizer was used as FC unit to investigate the enhancement of sugar content in CW. The effect of initial concentration of CW was then investigated on the performance of the PFC system through the Effective Partition Constant (K) value and increment of sugar content. It was found that lower initial concentration yielded lower K, which is favourable and high sugar content. The best K achieved was of 0.3101 and the highest sugar content increment acquired was 53% with the range of initial concentration investigated (3 to 5%Brix).

Fuzzy ignition timing control for a spark ignition engine

2000 ◽  
Vol 214 (3) ◽  
pp. 297-306 ◽  
Author(s):  
W Wang ◽  
E. C. Chirwa ◽  
E Zhou ◽  
K Holmes ◽  
C Nwagboso
Keyword(s):  
Fuzzy Logic ◽  
Detection System ◽  
Open Loop ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Coolant Temperature ◽  
Optimum Level ◽  
Ignition Timing ◽  
Timing Control ◽  
Engine Design

It is well known that the optimum ignition timing, which gives the maximum brake torque (MBT) for a given engine design, varies with the rate of flame development and propagation in the cylinder. This depends, among other factors, on engine design and operating conditions, and on the properties of the air-fuel mixture. In modern engines the ignition timing is generally controlled by fixed open-loop schedules as functions of engine speed, load and coolant temperature. It is desairable that this ignition timing can be adjusted to the optimum level producing the best torque to obtain minimum fuel consumption and maximum available power. This paper presents an ignition timing control system based on fuzzy logic theory. A pressure sensor system ws developed for the determination of combustion parameters and ignition control on a Ford 1600cm3 four-cylinder engine fuelled with natural gas. Several tests were carried out in optimizing the pressure detection system. The results obtained provide important information compatible with intelligent control of the engine using fuzzy logic technology. Moreover, tests carried out to date using this technology show good results that fit quite well with the original engine output torque characteristics.

scholarly journals Systematic Experimental Investigation of Segregation Direction and Layer Inversion in Binary Liquid-Fluidized Bed

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 177
Author(s):  
Alberto Di Renzo ◽  
Giacomo Rito ◽  
Francesco P. Di Maio
Keyword(s):  
Experimental Investigation ◽  
Operating Conditions ◽  
Industrial Processes ◽  
Process Unit ◽  
Separation Processes ◽  
Solids Concentration ◽  
Expansion Range ◽  
Surface Expansion ◽  
Density Ratios ◽  
Inversion Phenomenon

Multi-component liquid-fluidized beds are encountered in a variety of industrial processes. Often, segregation severely affects the performance of the process unit. Unfortunately, size-driven and density-driven separation processes may occur with a complex interplay, showing prevailing mechanisms that change with the operating conditions. For example, when the solids exhibit contrasting differences in size and density, even the direction of segregation can turn out hard to predict, giving rise for some systems to the so-called “layer inversion phenomenon”. A systematic experimental investigation is presented on 14 different binary beds composed of glass beads and ABS spheres with different size and density ratios and different bed composition. The analysis allows assessing the reliability of a model for predicting the segregation direction of fluidized binary beds (the Particle Segregation Model, PSM). By measurements of the solids’ concentration at the surface, expansion/segregation properties and the inversion voidage are compared with the PSM predictions, offering a direct means of model validation. Both the segregation direction throughout the expansion range and the value of the inversion voidage are compared. Extensive qualitative agreement is obtained for 12 out of 14 fluidized mixtures. Quantitatively, the average discrepancy between predicted and measured inversion voidage is below 5%, with a maximum of 17%.

scholarly journals Review on the Relationship Between Liquid Aerospace Fuel Composition and Their Physicochemical Properties

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
High Performance ◽  
Freezing Point ◽  
Operating Conditions ◽  
Hydrocarbon Fuels ◽  
Least Square ◽  
Fuel Properties ◽  
Molar Ratio ◽  
Fuel Composition

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.

scholarly journals Progressive Freeze Concentration of Coconut Water and Use of Partial Ice Melting Method for Yield Improvement

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
J. A. E. C. Jayawardena ◽  
M. P. G. Vanniarachchy ◽  
M. A. J. Wansapala
Keyword(s):  
Total Yield ◽  
Liquid Product ◽  
Operating Conditions ◽  
Coconut Water ◽  
Optimum Operating ◽  
Liquid Food ◽  
Ice Melting ◽  
Freeze Concentration ◽  
Melting Technique ◽  
Sample Vessel

Coconut water is a highly nutritious liquid food which is a by-product of the desiccated coconut industry. Freeze concentration is the most suitable concentration method for coconut water since the low-temperature operation for concentration does not deteriorate the original quality of coconut water. Suspension freeze concentration (SFC) and progressive freeze concentration (PFC) are the available FC methods, and SFC is a complex and expensive method compared with PFC. PFC is a novel freeze concentration technique to concentrate liquid food by using a simple system. The limitation of PFC is the lower product yield than SFC, and to overcome the problem, the partial ice-melting technique can be used. A simple cylindrical apparatus was used for PFC which consists of a sample vessel, agitator system, and a cooling bath (at −23°C±2°C temperature). The final concentration of the liquid product was directly affected by the apparatus agitator speed and sample vessel dipping speed. PFC agitator speed of 290 rpm and dipping speed of 1.3 cm h-1 were reported as the optimum operating conditions to achieve the highest concentration for the PFC apparatus used in this study. Using optimized agitation speed and dipping speed, coconut water was concentrated up to Brix 8.5° from the initial concentration of Brix 3.5°. PFC coconut water achieved 73.56% of total yield, 2.42 of concentration ratio, 0.7° of ice phase concentration, and 0.08 of effective partition coefficient. The partial melting technique was successfully explored by recovering initial ice fractions with high solute concentrations, and the total yield was improved up to 80%.

Flash Pyrolysis of Coal with Solid Heat Carrier in a Fluidized Bed

2014 ◽  
Vol 953-954 ◽  
pp. 1153-1156
Author(s):  
Ceng Ceng Geng ◽  
Shu Yuan Li ◽  
Shao Hua Liu ◽  
Ji Li Hou ◽  
Wen Zhi Shang
Keyword(s):  
Reaction Time ◽  
Fluidized Bed ◽  
Heat Carrier ◽  
Pyrolysis Temperature ◽  
Freezing Point ◽  
Coal Tar ◽  
Operating Conditions ◽  
Mass Ratio ◽  
Flash Pyrolysis ◽  
Oil Fraction

Flash pyrolysis of Shenmu coal with solid heat carrier was carried out in a fluidized bed using semi-coke as the solid heat carrier and nitrogen as the carrier gas. The effects of pyrolysis temperature, reaction time and mass ratio of heat carrier to coal on the yields of products were studied. It is found that the best operating conditions involving pyrolysis temperature 550°C, reaction time 6 min and mass ratio of heat carrier to coal 2. The properties of coal tar from fluidized bed, such as density, viscosity, freezing point, carbon residue and hydrogen carbon atom ratio, are almost higher than that of the above water coal tar and lower than that of the below water coal tar, while the above and below water coal tar obtained from Sanjiang squared retort. The results of simulation distillation show that gasoline and diesel fractions of coal tar from fluidized bed are higher than that of below water coal tar and lower than that of above water coal tar, while the heavy oil fraction is opposed.

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