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

Author(s):  
Ю.С. Беззаботов ◽  
Е.О. Ивченко

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.

2021 ◽  
Vol 39 (3) ◽  
pp. 810-816
Author(s):  
Wan Nurlaila Mat Desa ◽  
Ahmad Fudholi ◽  
Henny Sudibyo ◽  
Ghalya Pikra ◽  
Nugrahaning Sani Dewi ◽  
...  

In this study, a greenhouse solar dryer with double-pass multi-hollow collector for leaf drying was design, constructed, and evaluated. From the result, the double pass solar air collector with multi-hollow tube is capable of increasing air temperature by 5.5℃-10.8℃ compared to ambient air temperature. Thermal efficiency of the dryer was evaluated for passive and active modes, where 47.2% and 50% are recorded respectively. The moisture reduction on mass basis in passive and active dryer recorded was 44% and 74%, respectively. The specific moisture extraction rate (SMER) and specific energy consumption (SEC) of passive dryer was determined to be 0.198 kg per kWh and 5.047 kWh per kg, and active dryer at 0.210 kg per kWh and 4.769 kWh per kg, respectively.


Author(s):  
H. T. Sabarez ◽  
S. Keuhbauch ◽  
K. Knoerzer

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 


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hang Lv ◽  
Qiao Xiong ◽  
Daoguang Liu ◽  
Xu Wu

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.


Author(s):  
Punit Singh ◽  
Prabal Talukdar

Abstract Drying characteristics of elephant foot yam (EFY) are determined at three different air velocities and temperatures using an innovative convective dryer. The performance of the convective dryer is also determined and compared based on four parameters namely total energy consumption, specific energy consumption (SEC), drying and thermal efficiency, working in kinetically controlled regime (KCR), and equilibrium controlled regime (ECR). EFY has excellent medicinal properties and used for the treatment of various diseases; in spite of that, its drying characteristics have not been reported. The entire drying process of the EFY sample can be divided into three stages, and it is observed that around 80% of the moisture is removed in the first stage and only 5% of the moisture is removed in the last stage. The constant drying rate period is absent, and depending on the different slopes, the entire drying rate period comes under three falling rate periods. A correlation of EFY with air velocity and temperature is developed, and the maximum and minimum values of effective moisture diffusivity (EMD) are found to be 2.65 × 10−10 and 7.15 × 10−10 m2/s, respectively.


1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  


2021 ◽  
Vol 13 (10) ◽  
pp. 5617
Author(s):  
Raman Kumar ◽  
Sehijpal Singh ◽  
Ardamanbir Singh Sidhu ◽  
Catalin I. Pruncu

This paper’s persistence is to make an inclusive analysis of 268 documents about specific energy consumption (SEC) in machining operations from 2001 to 2020 in the Scopus database. A systematic approach collects information on SEC documents’ primary data; their types, publications, citations, and predictions are presented. The VOSviewer 1.1.16 and Biblioshiny 2.0 software are used for visualization analysis to show the progress standing of SEC publications. The selection criteria of documents are set for citation analysis. The ranks are assigned to the most prolific and dominant authors, sources, articles, countries, and organizations based on the total citations, number of documents, average total citation, and total link strength. The author-keywords, index-keywords, and text data content analysis has been conducted to find the hotspots and progress trend in SEC in machining operations. The most prolific and dominant article, source, author, organization, and country are Anderson et al. “Laser-assisted machining of Inconel 718 with an economic analysis”, the Int J Mach Tools Manuf, Shin Y.C., form Purdue University Singapore, and United States, respectively, based on total citations as per defined criteria. The author keywords “specific cutting energy” and “surface roughness” dominate the machining operations SEC. SEC’s implication in machining operations review and bibliometric analysis is to deliver an inclusive perception for the scholars working in this field. It is the primary paper that utilizes bibliometric research to analyze the SEC in machining operations publications expansively. It is valuable for scholars to grasp the hotspots in this field in time and help the researchers in the SEC exploration arena rapidly comprehend the expansion status and trend.


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