scholarly journals Research on low temperature drying characteristics of different types of manure and biogas residue

2020 ◽  
Vol 194 ◽  
pp. 02014
Author(s):  
Xiu Fangtao ◽  
Zhu Hongguang ◽  
Xu Yupeng

For the biogas project which does not have the ability to return to the field nearby, the outlet of biogas residue is one of the important bottlenecks restricting the development of biogas engineering. Deep dehydration and drying is a reliable basis for commercial utilization of biogas residue, especially combined with waste heat utilization of cogeneration of biogas. Therefore, three kinds of biogas residue raw materials were dried at low temperature by hot drying method in this paper. The drying temperature, the thickness of biogas residue and the backmixing amount of dry biogas residue were selected as three influencing factors. The drying time, drying rate and residual water ratio were taken as dependent variables. The drying characteristic curve of biogas residue was obtained, and the influence of each factor on the drying process of biogas residue was analyzed and compared. The results showed that the drying time of three kinds of biogas residue decreased with the increase of drying temperature. At the same temperature, the drying time decreases with the decrease of thickness. The dry biogas residue backmixing can’t optimize the drying characteristics and even increase the drying energy consumption.

2020 ◽  
Vol 12 (1) ◽  
pp. 403
Author(s):  
Xuanyang Li ◽  
Baoming Li ◽  
Qin Tong

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.


Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.


The study is aimed experimentally and compared with the theoretical results of drying kinetics of Nagpur orange fruit dried in a hot air electrical dryer. Orange fruit is highly perishable and needs to be consumed or processed immediately after harvest. Drying or dehydration is one of the most practical methods of preserving food products. Therefore, thin layer drying characteristics of falling rate of Nagpur orange are determined experimentally under different conditions of drying air temperatures, relative humidity and air velocities for different moisture contents. Thin layer models like Wang and Singh, Page and Henderson have been compared with Experimental results. The knowledge of drying kinetics helps for identification of exact drying time and air flow velocity for different moisture content. Here drying operation is carried out at a velocity of 1m/sec and 1.25 m/sec for different temperature of 55°C, 65°C and 75°C. This analysis reveals that drying temperature has a more significant effect on moisture removal while velocity has the least effect. Drying rate is found to increase with the increase in drying temperature and reduce with drying time. Experimental data is statistically correlated by plotting the drying characteristics curve. The analysis reveals that Wang and Singh's model is a better model to explain the drying behavior of Nagpur Orange fruit (R2=0.9888).


2018 ◽  
Vol 192 ◽  
pp. 03041
Author(s):  
Setthawat Thanimkarn ◽  
Ekkapong Cheevitsopon ◽  
Jiraporn Sripinyowanich Jongyingcharoen

This study aimed to investigate the effect of drying temperature (40, 60, 80, and 100°C) on drying characteristics of Cissus quadrangularis Linn. (CQ) undergoing convective drying. Physical properties and phytochemicals of the dried CQ were also evaluated. CQ with the thickness of 5 mm was dried from about 10 to 0.1 g water/g dry matter. The results showed that increasing drying temperature increased drying rate (DR) and effective moisture diffusivity (Deff) and consequently decreased drying time. The drying time, maximum DR, and Deff were in the ranges of 85-1920 min, 0.0059-0.0248 g water/g dry matter·min, and 0.7302-9.1281×10-9 m2/s, respectively. Lower drying temperature could preserve quality of the dried CQ. Decreasing drying temperature resulted in greener and lower bulk density and shrinkage. The greatest total phenolic content (TPC) and quercetin content were obtained by drying the CQ at 60°C.


2021 ◽  
Vol 10 (1) ◽  
pp. 24-35
Author(s):  
Andi Muhammad Irfan ◽  
Nunik Lestari ◽  
Arimansyah Arimansyah ◽  
A Ramli Rasyid

This study was aimed to determine the drying kinetics of chilies that have been pretreated with low temperature long time (LTLT) blanching. Drying chilies with LTLT blanching pretreatment at 60, 70, and 80 oC for 20 minutes was assigned as treatment in this research. Drying chillies with high temperature short time (HTST) blanching pretreatment, without blanching pretreatment in the dryer, and without blanching pretreatment in direct sunlight were also studied as the comparison. The results showed that chilies treated with blanching pretreatment, both LTLT and HTST, have a faster drying rate and achieve the target moisture content faster than chilies that were not blanched. The color of dried chilies that were dried in a dryer was also better than dried chilies that were dried in the sun. Of all the blanching treatments, chilies with LTLT blanching pretreatment at 80 oC for 20 minutes had the fastest drying rate, a drying time of 34 hours, and the attractive dried chilli color. The evaluation results also showed that the Page model was the most suitable model to describe the drying characteristics of chilies with LTLT pretreatment blanching, with R2 ranging from 0.9913-0.9935, X2 ranging from 0.0005-0.0009, and RSME ranging from 0.0221-0.0293. Keywords: Chili; blanching; color; drying; mathematical model   ABSTRAK Penelitian ini bertujuan untuk mengetahui kinetika pengeringan cabai yang diberi perlakuan awal low temperature long time (LTLT) blanching atau blansing pada suhu rendah dalam waktu yang relatif lama. Perlakuan pada penelitian ini yaitu pengeringan cabai dengan blansing metode LTLT pada suhu 60o, 70o, dan 80oC selama 20 menit. Sebagai pembanding, dilakukan juga pengeringan dengan perlakuan awal metode high temperature short time (HTST) blanching, pengeringan cabai tanpa perlakuan awal blansing di dalam alat pengering, serta pengeringan cabai tanpa perlakuan awal blansing di bawah sinar matahari secara langsung. Hasil penelitian menunjukkan bahwa cabai dengan perlakuan awal blansing, baik blansing metode LTLT maupun HTST, memiliki laju pengeringan yang lebih tinggi sehingga lebih cepat mencapai kadar air target dibandingkan dengan cabai tanpa perlakuan blansing. Warna cabai kering yang dihasilkan pada alat pengering juga lebih baik dari cabai kering yang dikeringkan langsung di bawah sinar matahari. Dari seluruh perlakuan yang melibatkan proses blansing, cabai dengan blansing metode LTLT pada suhu 80oC selama 20 menit merupakan perlakuan dengan laju pengeringan tercepat, dengan waktu pengeringan selama 34 jam, dan warna produk cabai kering yang menarik. Hasil evaluasi juga menunjukkan bahwa model Page adalah model yang paling sesuai untuk menggambarkan karakteristik pengeringan cabai dengan perlakuan awal blansing metode LTLT, dengan R2 berkisar antara 0.9913-0.9935, X2 berkisar antara 0.0005-0.0009, dan RSME berkisar antara 0.0221-0.0293. Kata kunci: Blansing; cabai; model matematika; pengeringan; warna


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 


Author(s):  
Marina Beleckaya ◽  
Alexander Vladimirov ◽  
Oksana Kozlova ◽  
Irina Milenteva

Introduction. Milk has a high nutritional value and is a vital component of human diet. Today, the dairy market is one of the largest and actively developing food markets. However, this industry is characterized by such problems as seasonality and poor transportability of raw materials. These problems particularly affect small farms. Deep processing of dairy raw materials to obtain dry powders is the most effective way to solve these problems. The research objective was to develop a low-tonnage dryer for producing milk powder on small farms and to select the optimal drying temperature. Study objects and methods. The research featured whole milk of the ‘Svoya Ferma’ brand, mass fraction of fat = 3.4–4.5%. The research was performed on the premises of Kemerovo State University (Kemerovo, Russia). The milk was dried on a pilot sample of the roller dryer developed by the research team. The dryer consisted of a vessel, heating drums, and a microcontroller, which was connected to the temperature sensor and the control circuit of the power part, which had a powerful rectifier and pulse regulator. Results and discussion. When the drying temperature exceeded 98°C, the characteristics of the milk powder deteriorated, and the milk failed to meet the State Standard. The optimal drying temperature was 92–95°C, since at this temperature all the characteristics, except for the solubility index, corresponded to the State Standard. The sensory and physical properties of the milk powder were improved by reducing the drying time and the distance between the knife and the drum. Conclusion. Further experiments have to be performed to determine the optimal rotation speed of the drums and the distance between the knife and the drum.


2019 ◽  
Vol 56 (1) ◽  
pp. 34
Author(s):  
Parul Bora ◽  
Asha Kawatra

<em>Experiments were conducted on pre treated dehydrated oyster mushroom with steeping in citric acid and sodium chloride and blanching to investigate the effect of pre treatments and drying methods on drying characteristics of mushroom and quality of dried oyster mushroom. Drying was accomplished in a cabinet dryer using hot air at 40<sup>O </sup>C, 60<sup>O</sup>C and by sun drying. The drying characteristics of mushroom were not affected by the pre-treatments significantly. However, the rate of drying increased with the increase in drying temperature. Increase in drying temperature significantly reduced the total drying time. Pre treatments and drying temperature had adverse influence on the rehydration ratio, hardness and colour of the dehydrated mushrooms. Blanching improves the colour of the dehydrated mushroom but increased hardness also. A loss of protein was observed during blanching</em>


2011 ◽  
Vol 130-134 ◽  
pp. 401-405
Author(s):  
Xiao Qiang Wang ◽  
Shi Ye Feng ◽  
Shu Hua Su ◽  
Zhi Bo Zhang ◽  
Qiang Lu ◽  
...  

This paper presents the drying characteristics of rice husk and cornstalk with high moisture content at fixed temperatures. Experiments were performed in an oven drier, to reveal to the effects of initial moisture content, bed thickness and drying temperature on the biomass drying characteristics. The results indicated that the drying time was decreased as the rising of the drying temperature, and increased along with the initial moisture content and bed thickness. Moreover, the risk husk was easy to be dried than the cornstalk.


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