scholarly journals Coupling electro-dewatering and low-temperature air-drying for efficient dewatering of sludge

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hang Lv ◽  
Qiao Xiong ◽  
Daoguang Liu ◽  
Xu Wu
Keyword(s):  
Energy Consumption ◽  
Low Temperature ◽  
Physical Modeling ◽  
Lower Energy ◽  
Electric Field Intensity ◽  
Drying Process ◽  
Air Drying ◽  
Front End ◽  
Sludge Cake ◽  
Low Temperature Drying

AbstractThis study investigated the effects of electro-dewatering on subsequent low-temperature drying at various potentials and the characteristics of low-temperature air-drying sludge were explored through experiments and multi-physical modeling. Experimental results showed that the extracellular polymeric substance (EPS) content in the sludge was reduced during electro-dewatering process, even the species of organic matter was changed, as well as the dewatered cake tend to form many seepage channels, crack and a certain number of holes. These changes in the properties and structure were conducive to the subsequent low-temperature drying process. For air-drying process, the mass of the sludge cake variation was simulated and results were consistent with the experimental phenomenon. Firstly, the weight of the sludge cake was decreased approximately linearly with time, then tended to stable and reached the dewatering limitation finally. The applied higher electric field intensity (25 V cm−1) in the front-end electro-dewatering were conducive to promote water vapor diffusion activity in air-drying stage. Energy consumption and yield analysis results indicated that the combined technology has lower energy consumption and higher yield than that of directly low-temperature drying.

scholarly journals Ultrasound assisted low temperature drying of food materials

2018 ◽  
Author(s):  
H. T. Sabarez ◽  
S. Keuhbauch ◽  
K. Knoerzer
Keyword(s):  
Energy Consumption ◽  
Low Temperature ◽  
Product Quality ◽  
Direct Contact ◽  
Lower Energy ◽  
Drying Time ◽  
Indirect Transmission ◽  
Ultrasound Assisted ◽  
Improved Design ◽  
Low Temperature Drying

An ultrasonic design based on the indirect transmission of ultrasonic energy from the ultrasound emitter through to the material to be dried was investigated to assist in low temperature drying of food materials. The application of the improved design tested in this work was found to enhance the low temperature drying by shortening the overall drying time of up to 45% (i.e., lower energy consumption and may enable better retention of product quality). This offers a promising approach towards a better applicability of ultrasound in industrial operation, since no direct contact between the sample and the ultrasonic emitter is needed. Keywords: ultrasound; drying; low temperature; drying intensification 

scholarly journals Effects of Low-Temperature Drying with Intermittent Gaseous Chlorine Dioxide Treatment on Texture and Shelf-Life of Rice Cakes

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 375
Author(s):  
Timilehin Martins Oyinloye ◽  
Won Byong Yoon
Keyword(s):  
Low Temperature ◽  
Shelf Life ◽  
Chlorine Dioxide ◽  
Microbial Inactivation ◽  
Cutting Process ◽  
Microbial Load ◽  
Processing Unit ◽  
Drying Process ◽  
Rice Cake ◽  
Low Temperature Drying

We investigated the effect of chlorine dioxide (ClO2) under low temperature drying to suppress rice cake stickiness during the cutting process by initiating the onset of retrogradation until the stickiness is minimized for shelf-life extension. The intermittent ClO2 application at low-temperature drying was conducted at 10 °C for different drying periods (0, 6, 12, 18, and 24 h). Texture analysis showed significant differences with increasing values of hardness (901.39 ± 53.87 to 12,653 ± 1689.35 g) and reduced values of modified adhesiveness (3614.37 ±578.23 to 534.81 ± 89.37 g). The evaluation of rice cake stickiness during the cutting process revealed an optimum drying period of 18 h with no significant difference (p ≤ 0.05) compared to the 24 h drying process. Microbial contamination during the drying process increased, with microbial load from 6.39 ± 0.37 to 7.94 ± 0.29 CFU/g. Intermittent ClO2 application at 22 ppm successfully reduced the microbial load by 63% during drying process. The inhibitory property of ClO2 was further analyzed on a sample with high initial microbial load (3.01 ± 0.14 CFU/g) using primary and modified secondary growth models fitted to all experimental storage temperatures (5–25 °C) with R2 values > 0.99. The model demonstrated a strong inhibition by ClO2 with microbial growth not exceeding the accepted population threshold (106 CFU/g) for toxin production. The shelf-life of rice cake was increased by 86 h and 432 h at room temperature (25 °C) and 5 °C respectively. Microbial inactivation via ClO2 treatment is a novel method for improved food storage without additional thermal sterilization or the use of an additional processing unit.

scholarly journals Comparative Evaluation of Sulfur Compounds Contents and Antiobesity Properties of Allium hookeri Prepared by Different Drying Methods

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Min Hye Yang ◽  
Na-Hyun Kim ◽  
Jeong-Doo Heo ◽  
Jung-Rae Rho ◽  
Kwang Ju Ock ◽  
...  
Keyword(s):  
Low Temperature ◽  
Body Weight Gain ◽  
The Body ◽  
Drying Methods ◽  
Organosulfur Compounds ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Allium Hookeri ◽  
Low Temperature Drying

Despite the nutritional and medicinal values of Allium hookeri, its unique flavor (onion or garlic taste and smell) coming from sulfur containing compounds limits its usage as functional food. For comparative study, A. hookeri roots were prepared under two different drying conditions, namely, low-temperature drying that minimizes the volatilization of sulfur components and hot-air drying that minimizes the garlic odor and spicy taste of A. hookeri. In GC/MS olfactory system, the odorous chemicals and organosulfur compounds such as diallyl trisulfide, dimethyl trisulfide, and dipropyl trisulfide were significantly decreased in hot-air drying compared to low-temperature drying. The spiciness and saltiness taste were noticeably reduced, while sourness, sweetness, and umami taste were significantly increased in hot-air dried A. hookeri according to electronic tongue. Although the content of volatile sulfur components was present at lower level, the administration of hot-air dried A. hookeri extract (100 mg/kg p.o.) apparently prevented the body weight gain and improved insulin resistance in C57BL/6J obese mice receiving high fat diet. Results suggested that the hot-air dried A. hookeri possessing better taste and odor might be available as functional crop and bioactive diet supplement for the prevention and/or treatment of obesity.

Study on Microwave Drying Process and Drying Characteristics of Sewage Sludge

2013 ◽  
Vol 838-841 ◽  
pp. 2643-2647
Author(s):  
Jin Ping Li ◽  
Meng Yao Li ◽  
Wen Yao ◽  
Ni Wang
Keyword(s):  
Energy Consumption ◽  
Sewage Sludge ◽  
Lower Energy ◽  
Microwave Drying ◽  
Drying Rate ◽  
Municipal Sludge ◽  
Drying Process ◽  
Drying Characteristics ◽  
Pretreatment Time ◽  
Short Time

Combination of oven and microwave and only oven are two ways to study municipal sludge,and it investigates whether different size, microwave drying pretreatment, pretreatment time and oven temperature characteristics have effect on drying characteristics. The results shows that: using microwave to dry sludge need short time, the drying rate is fast, combination of oven and microwave has higher drying rate and lower energy consumption than only oven.

ESTIMATION OF EFFICIENCY OF LOW TEMPERATURE DRYING ON THE BASIS OF ENERGY ANALYSIS OF PROCESSES IN ELEMENTS OF DRYING UNIT

2019 ◽  
Author(s):  
Ю.С. Беззаботов ◽  
Е.О. Ивченко
Keyword(s):  
Energy Consumption ◽  
Low Temperature ◽  
Energy Analysis ◽  
Specific Energy Consumption ◽  
Significant Proportion ◽  
Physical Models ◽  
Heat Regeneration ◽  
And Performance ◽  
Low Temperature Drying ◽  
Thermal Transformer

Рассмотрена работа двухконтурной установки низкотемпературной сушки (ДКУНТС) пищевых продуктов с применением компрессорного термотрансформатора теплового насоса. На основании физической модели ДКУНТС выполнен математический анализ энергетической эффективности процесса сушки. Получены аналитические зависимости удельных энергозатрат на сушку продуктов и режимные характеристики работы ДКУНТС. Установлено, что существенная доля энергозатрат в ДКУНТС связана со значительной тепловой нагрузкой на внешний электронагреватель НГЭ. В связи с этим предложено использовать тепловую энергию отработанного сушильного агента путем регенерации тепла в цикле работы установки, что позволит снизить энергозатраты на сушку пищевых продуктов в ДКУНТС. The work of a twocircuit installation of low temperature drying TCILTD of food products using a compressor thermal transformer a heat pump was considered. On the basis of physical models TCILTD made a mathematical simulation of processes and computer simulation of the analytical dependence of the specific energy consumption for drying and performance characteristics of the work TCILTD. It is established that a significant proportion of energy consumption is associated with a significant heat load on the external heater NGE, in which it is proposed to use the thermal energy of exhaust of the drying agent by means of heat regeneration in the cycle of TCILTD.

A simplified model for predicting shrinkage during low temperature air drying of porous food materials

2019 ◽  
Author(s):  
Ankita Sinha ◽  
Atul Bhargav
Keyword(s):  
Low Temperature ◽  
Transport Model ◽  
Computational Cost ◽  
Spatial Location ◽  
Moisture Loss ◽  
Drying Process ◽  
Yield Data ◽  
Complex Deformation ◽  
Air Drying ◽  
Shrinkage Temperature

Food materials shrink when they are air-dried. However, owing largely to the complexity of modelling, most drying models so far have neglected this shrinkage, leading to inaccurate predictions. The empirical nature, inability to yield data on location-specific deformations and computational cost of detailed poro-mechanistic analyses and complex deformation modelling approaches make them unattractive for models that could be used in real-time process control algorithms. In this work, we develop a simplified transport model to predict spatial and temporal shrinkage during low temperature air drying process, and validate the model with experiments. In such drying, volumetric change is dominated by moisture loss; therefore the role of gas induced porosity is neglected. This model predicts shrinkage, temperature and moisture content at each spatial location at time intervals during the drying process. The model agrees well with experiments conducted by us (reported in this paper) as well as with those conducted by others (taken from the literature) on food samples. We expect that this generalized model will find wide applications in the food processing industry.

scholarly journals The Effect of Drying Temperature on Nitrogen Loss and Pathogen Removal in Laying Hen Manure

2020 ◽  
Vol 12 (1) ◽  
pp. 403
Author(s):  
Xuanyang Li ◽  
Baoming Li ◽  
Qin Tong
Keyword(s):  
Low Temperature ◽  
Nitrogen Loss ◽  
Ambient Air ◽  
Laying Hen ◽  
Ammonia Emission ◽  
Drying Process ◽  
Drying Time ◽  
N Content ◽  
Drying Temperature ◽  
Low Temperature Drying

Exhaust air from the poultry houses or ambient hot air are normally utilized to dry the laying hen manure extensively in the summer in China. The drying process can not only reduce the moisture of lay hen manure but can also have a degerming effect. However, the ammonia emission is considered as one of the major issues of laying hen manure drying and air pollution scouse. Then, it is not clear that whether the ammonia emission increased using the hot ambient air to dry laying hen manure in summer and whether increasing the temperature can inactivate more bacteria during low temperature drying process. Therefore, the main works of this study were to investigate the evolution of ammonium nitrogen (NH4-N) content, organic nitrogen (Org-N) content, and total bacteria count vs. time during the low-temperature drying process of laying hen manure at different drying temperatures. The results showed that increasing drying temperature can reduce the energy consumption of the manure drying system, but can increase the loss of NH4-N. The Org-N content among the three drying temperatures within same drying time was not significantly different (p > 0.05), which suggested that increasing the temperature did not accelerate the degradation of Org-N during low-temperature drying process. Low-temperature drying had weak destruction of bacteria in laying hen manure and the end dried manure still had a great number of bacteria.

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