• Korean Journal of Food Science and Technology
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• v.9 no.4
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• pp.245-250
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• 1977

Experiment were conducted to find out the effective drying method of citrus peel produced in Korea by varying the temperature of hot air, surface area of peels, peels from several citrus varieties and physicochemical treatment of the peel. 1. About $3{\sim}6\;days$ were required to reduce the moisture level of the peel from 70%(wet basis) to 20% at room temperature without forced convection. 2. Drying was speeded up until the temperature of hot air reached $60^{\circ}C$. Beyond that no significant increase in drying rate was observed. About 50 minutes were needed to reduce the moisture level (dry basis) to below 10% at $60^{\circ}C$ by forced convection 3. When the peel surface area was increased twice by cutting the peel into 256 fractions, the overall drying time (the time required to reduce the moisture level to 10%, dry basis) was shortened to 15 minutes from 50 mintes of the original peel. 4. No significant difference in drying rate was observed among the peels from several citrus varieties except Shaddock jabon and Citrus ponki tanaka, which dried more slowly than others. 5. Treatment of $Ca(OH)_2$ and the pressing of the peel before drying were effective in drying only when the initial moisture content was substantially higher.

• Journal of agriculture & life science
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• v.53 no.5
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• pp.137-143
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• 2019

To manufacturing of solid fuel by reuse of the wastes, the drying unit which have 500 kg/hr of drying capacity was developed and experimentally evaluate the performance. The spinach grown in Nam-hae island were used for the experiments and investigated of the heated-air drying characteristics as the inlet amount of raw materials, raw material stirring status, conveying type and drying time. The drying air heated by the energy derived from the steam which is supplied from the incineration plant. The moisture contents of raw materials were measured 85.65%. The inlet flow rate of drying air made a difference as the depth of the raw materials loaded on the drying unit and temperature has showed 108~144℃. The drying speed of the mixed drying more than doubled as that of non mixed drying under the same drying type, inlet amount, drying time and drying air temperature. In each experiment, the drying capacity have showed over 500 kg/hr. A drying efficiency of the ratio of drying consumption energy to input energy was 33.46%, lower than the average of 57.76% for the 157 conventional dryers. Because developed dryer must have a drying time of less than one hour, it is considered that the dry efficiency has been reduced due to the loss of wind volume during drying. If waste heat from incineration plant is used as a direct heat source, the dry air temperature is expected to be at least 160℃, greatly improving the drying capacity.

• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.31-37
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• 2003

Flat-sawn 32 mm-thick boards of Populus alba×P. glandulosa, one of major plantation species in this country, were dried in conventional, high-temperature and microwave-vacuum (MW/V) kilns. The average green specific gravity of the specimens used in this study was 0.349±0.074. Their average green moisture contents of heartwoods and sapwoods were around 200% and 100%, respectively. From green to oven-dry they shrunk 2.4 and 7.3% in radial and tangential directions, respectively, and there was no discrepancy between heartwoods and sapwoods. It took 65, 35 and 22 hours to dry from green to 10% moisture content in conventional, high-temperature and MW/V kilns, respectively. A colorimetry study showed that the surface color of the specimens dried in a MW/V kiln was clearer and lighter than those in other kilns.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.193-198
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• 2000

분무건조장치는 Solution, Slurry, Emulsion, Colloidal Suspension 등의 액상원료를 미립화하여 표면적을 증가시켜 수열면적을 크게 하여 열풍과 직접 접촉함으로써 순간적으로 건조를 행하여 액상원료로부터 바로 분립상의 제품을 얻는 건조법이다. 분유를 비롯하여 Instant 식품류, 합성세제, 염료, 안료, Ceramic, 공해 폐액의 처리에 이르기까지 폭넓게 이용되고 있다. 분무건조기는 통기, 회전, 기류 건조기 등 다른 건조기에 비하여 고도의 설계 및 제작 기술을 요하며, 설계에 있어서 일부 이론적인 취급이 행해지고 있는 것은 사실이나 아직은 경험에 의존하고 있는 현실이다. 국내에서 제작되고 있는 분무건조기의 열효율은 25-33%로 선진국의 35-48%에 비해 매우 낮다. 국내에서 사용되고 있는 분무건조기의 92%는 덴마크, 일본 등에서 수입된 것이다.(중략)

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.215-220
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• 2000

건조는 열풍, 스팀 및 전자기파 등의 직접 또는 간접적인 에너지를 투입하여 최종 제품, 가공, 후처리 과정에서 수분을 제거하는 필수 단위공정으로서 화공, 섬유, 식품, 제지·목재, 금속부품 및 폐기물 등에 이르기까지 모든 산업의 생산과정에서 널리 사용되고 있다. 건조공정은 국내 총에너지소비량의 1.2%('95년기준 1,413천TOE), 산업부문 에너지소비량의 2.2%를 소비하는 에너지다소비 장치의 하나이다. 실제론 산업분야 건조설비 사용업체의 에너지사용 비중 중에서 건조공정의 에너지사용 비중이 30%를 초과하고 있으나, 대부분의 건조공정의 에너지 이용효율이 50%이하로서 매우 낮은 실정이다.(중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5628-5636
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• 2012

Effective drying method of sewage sludge is researched in this study. To dry the sludge, chain crusher flash dryer was adopted to remove moisture content in the cell which is mostly responsible for the sludge moisture content. And Pilot plant experiment was conducted in real life sewage treatment plant to study effect and characteristics of operating conditions. Operating variables include sludge feeding rate, rotational speed of chain, process temperature and feed moisture content. As rotational speed of chain increased, product yield of sludge increased, and the performance of the testing system increased. And, as process temperature increased, the sludge drying efficiency increased. It is found that optimum feed moisture content is at 60% which shows the maximum sludge product yield and about 10 moisture content(%) of sludge product. Sludge feed rate showed optimal value, and when the sludge feed rate is exceeded, sludge product yield did not increased but the amount of residue increased. Pilot plant experiment results are as follow. The optimal condition for the rotational speed of chain 1600rpm(max. speed), final sludge discharge temperature $80^{\circ}C$, feed moisture content 60%, and feed rate 60kg/h. When the plant was operated at the optimal conditions, the final product showed fairly good results such as sludge product yield 85.5%, moisture content 11.0% and sludge drying efficiency 81.7%.

• Food Science and Preservation
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• v.20 no.2
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• pp.284-288
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• 2013

Omija (Schizandra chinensis B.) slices were dehydrated with 20, 40, and 60% (w/w) red algae extract (RAE), and 40% of RAE was selected as the proper processing concentration considering the dehydration efficiency and cost of the dehydrating agent. The RAE-treated omija samples were compared with the hot-air dried samples in terms of the qualities such as the rehydration capacity and total phenolic contents. The rehydration ratios of the RAE-treated samples were greater than those of the hot-air dried samples by 31%. The total phenolic contents of the RAE-treated samples (1304.8 mg GAE/100 g) were higher than those of the hot-air dried samples (999.5 mg GAE/100 g). Therefore, omija slices can be dehydrated with RAE without quality loss.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.237-242
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• 2022

In this study, a drying method that can effectively remove residual solvent from (+)-dihydromyricetin was developed. Residual acetone concentration was efficiently removed below ICH-specified value (5,000 ppm) by simple rotary evaporation with ethanol pretreatment. In addition, the residual ethanol met the ICH-specified value (5,000 ppm) by simple rotary evaporation through the addition of water, and the residual moisture also met the specified value (<4%) for active pharmaceutical ingredients. At all the drying temperature (35, 45, and 55 ℃), a large amount of the residual solvent was initially removed during the drying, and the drying efficiency increased when increasing the drying temperature. Removal of residual solvent by ethanol pretreatment was shown to be related to high vapor pressure of acetone-ethanol mixture and hydrogen bonding between acetone and ethanol.

• Korean Journal of Food Science and Technology
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• v.50 no.3
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• pp.339-343
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• 2018

Effects of different drying processes, such as hot air drying (HA), superheated steam with hot air drying (SHS/HA), and superheated steam with far infrared radiation (SHS/FIR), on the properties of cherry tomatoes (Solanum lycopersicum var. cerasiforme) were studied. Characteristics of dried cherry tomatoes were determined by examining the water content, internal microstructure, and rehydration capacity under different drying processes. Moreover, ascorbic acid (AA) and lycopene levels were also measured to evaluate thermal damage caused by drying. Cherry tomatoes dried using both SHS/HA and SHS/FIR had water content and water activity similar to those of intermediate moisture food, indicating partial dehydration after combined drying processes. Although AA and lycopene levels decreased drastically after drying, tomatoes dried using SHS/FIR showed the lowest losses of AA and lycopene among samples. Cherry tomatoes dried using SHS/FIR showed a less compact internal cell structure than that of cherry tomatoes dried using HA and SHS/HA, resulting in the highest rehydration capacity. These results suggest that a combined drying process such as SHS/FIR is more effective than conventional hot air drying for the production of partially dried cherry tomatoes with improved quality attributes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1242-1248
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• 2013

This study was performed to determine the effects of pretreatment (NT: non-treatment, BTS: boiling treatment with 3% sodium chloride, DTG: dipping treatment in glycerol) and drying methods (sun drying, hot air drying, and cold air drying) on the physicochemical properties and antioxidant activities of dried jujube (Zizyphus jujuba Mill.) fruits. Our results show that moisture content is lower (P<0.05) with DTG, and that moisture content is lower with hot air drying compared to other drying methods. The bulk density was highest with BTS. The soluble solids content was highest with DTG. Additionally, the soluble solids content were highest in the following order: hot air drying> cold air drying> sun drying. The titratable acidity of hot air drying was highest of all the drying methods. The titratable acidity was higher with NT and DTG, and the brix and acid ratio of sun drying was higher than other drying methods. Among the drying methods, BTS showed the best browning-retarding effect, whereas boiling treatment affected quality and color. The total polyphenol content from hot air drying and NT or DTG treatment was relatively higher than the content from BTS. The flavonoid content was highest with BTS, and all dried jujube showed relatively high antioxidant activities. The sensory evaluation results indicated that the organoleptic scores for overall preference were higher in the NT and DTG treatment groups. These results suggest that pretreatment and drying methods affect the quality of dried jujube fruit, and show that glycerol treatment with hot air drying can be applied to the production of high quality dried jujube.