• Journal of Biosystems Engineering
• /
• 제34권5호
• /
• pp.358-362
• /
• 2009

This study was conducted to evaluate the performance of a 12 tons capacity circulating concurrent flow rice dryer. An actual scale dryer with the capacity of 12 tons was developed to obtain a faster drying rate of 0.8~1.2%(w.b.)/h, while maintaining a lower drying energy consumption of 5,000 kJ/kg-water and achieving a drying quality that was comparable to a conventional cross-flow rice dryer. The Test-1 was conducted at $110^{\circ}C\;-\;20\;cmm/m^2$ and the Test-2 was conducted at $120-110-100-90^{\circ}C\;-\;20\;cmm/m^2$ under the same conditions as Test-1. In Test-1, the drying rate, drying energy consumption and crack ratio were 0.98 %(w.b.)/h, 4,573 kJ/kg-water and 3.2%, respectively. In Test-2, the drying rate, drying energy consumption and crack ratio were 0.74 %(w.b.)/h, 4,790 kJ/kg-water and 4.0%, respectively. The results of these tests demonstrated that this concurrent-flow dryer reached the desired drying rate, drying energy consumption and crack ratio.

• Journal of Biosystems Engineering
• /
• 제22권3호
• /
• pp.279-288
• /
• 1997

This study was worked out to obtain fundamental data needed for developing a continuous type dryer. The drying process in a cross-flow type continuous dryer was expressed as partial differential equations, and a drying simulation model for predicting rice moisture content, rice temperature, drying air absolute humidity, drying air temperature was developed by using the finite difference method. To validate the performance of the drying simulation model, a prototype continuous dryer was constructed in this study. The size of the test dryer was one-tenth to that of a commercial continuous dryer. The difference in the outlet rice moisture content between the predicted values and the measured values was within 0.5%, that of outlet rice temperature was below $3^{\circ}C$, that of drying air temperature in drying bed was within $8^{\circ}C$ and that of relative humidity of outlet drying air was big because of the different measuring point. In addition, a drying simulation model for a actual size continuous dryer with double flow was developed in this study. This drying simulation model included the rice mixing effect in the middle of drying length. The difference of outlet moisture content between the predicted and the measured values showed below 0.5% in this study.

• Advances in Energy Research
• /
• 제6권2호
• /
• pp.145-160
• /
• 2019

The world population reaches to about 7.7 billion in 2018 from 6.2 billion in 2000. This much growth in population results in increased energy demand and increased food supply. As the conventional energy sources are limited. These may deplete soon if consumed at this rate. So, the world is switching towards the utilization of non-conventional sources of energy. Energy from sun is the best method as it can not only solve the energy issue but also helps in meeting food demand by conserving it. Greenhouses are made for the purpose of food conservation. Various types of solar dryers are developed by researchers till now and still the effort is being putted to make them more efficient. Hybrid greenhouse is also effort toward utilization of solar energy in more efficient way. The paper presents the heat and mass transfer analysis of hybrid greenhouse solar dryer developed by different researchers till now. The review helps the researcher in understanding the heat and mass transfer taking place inside the hybrid greenhouse and how it can be further improved.

• 접착 및 계면
• /
• 제17권2호
• /
• pp.62-66
• /
• 2016

수용성 접착제의 경화 공정은 일반적으로 열풍건조기를 대부분 사용하고 있다. 열풍건조기는 열에 의해서만 수용성 접착제를 경화시키는 방법으로서, 충분한 경화를 위해 $100^{\circ}C$ 이상의 높은 온도와 최소 20 min 이상의 경화 공정을 요구하는 단점을 가지고 있다. 경화 과정 중에 온도가 너무 높을 경우, 접착제의 점도가 낮아져 접착에 방해가 될 수 있으며, 경화 과정 중에 발생하는 수분에 의해 경화 조건이 일정하게 유지되기 어렵다. 본 연구에서는 제습 막 건조기 시스템을 활용하여, 수용성 접착제의 경화 공정을 일정하게 유지시키고 공정 중의 제습을 통해 건조공기의 공급으로 경화시간을 단축하고자 한다. 제습 막 건조기 시스템을 활용한 최적의 경화 조건을 찾고, 제습 막 건조기 시스템의 효과를 확인하기 위하여, 제습 막 건조기와 강제순환 건조기를 적용한 경화 과정을 통해 접착력(peel strength)을 측정하여 비교 분석해 보았다.

• Journal of Biosystems Engineering
• /
• 제31권4호
• /
• pp.349-354
• /
• 2006

This study was performed to evaluate the performances for a concurrent flow rice dryer of pilot scale with devices for circulating rice. The pilot scale dryer with the capacity of 700 kg was developed to obtain design informations for the development of actual scale dryer of holding capacity of 10 tons. Three drying tests were conducted at two temperature levels of $100^{\circ}C\;and\;120^{\circ}C$, and two air flow rates levels of $28.5cmm/m^2\;and\;57.1cmm/m^2$. Drying conditions for Test-1, Test-2 and Test-3 were $100^{\circ}C\;-28.5cmm/m^2,\;120^{\circ}C-28.5cmm/m^2\;and\;120^{\circ}-57.1cmm/m^2}$ respectively. Drying rates were 0.73%(w.b./h) for Test-1, 0.90%(w.b./h) for Test-2 and 1.46%(w.b./h) for Test-3. The crack ratios of brown rice after drying ranged from 2.4% to 8.4%, and increased with the increase of drying rate and airflow rate. The energy consumptions were from 6,225 kJ/kg to 6,993 kJ/kg which was higher than that of conventional cross-flow rice circulating type dryer used in Korea. This results were due to the lower ambient air temperatures of $4.5^{\circ}C\;to\;13.4^{\circ}C$ during drying tests.

• 멤브레인
• /
• 제14권1호
• /
• pp.1-17
• /
• 2004

오늘날 대부분의 공압시스템에 압축공기 드라이어가 설치되어 있는데 이는 공압장치가 적절히 그리고 신뢰성 있게 작동되기 위해서는 제습된 공기를 사용해야 할 필요가 있을 뿐 아니라 이외에도 많은 이점을 더 가지고 있기 때문이다. 현재 사용되고 있는 압축공기드라이어는 전력이나, 흡착제의 사용으로 경제성이 떨어지며, 냉매제 등 환경적인 제약을 받고 있다. Membrane dryer는 경제적, 환경 친화적으로 이로우며, 각 산업체 뿐만 아니라 제습기능과 정수 기능이 합쳐진 에어정수기의 새로운 응용으로 물이 부족한 열대 우림지역에서 사용될 수 있다.

• 한국식품영양과학회지
• /
• 제37권1호
• /
• pp.60-65
• /
• 2008

다양한 방법으로 건조한 보리 잎의 일반성분을 분석한 결과 수분함량은 분석 방법에 따라 매우 큰 차이를 나타냈으며, 열처리 후 건조(HD), 음건(SD)한 보리 잎에서 동결건조(FD), 전자레인지 건조(MW)와 비교해볼 때 클로로필 함량이 높게 나타났다. 갈변작용은 열의 작용을 가장 받지 않은 동결건조(FD)한 보리 잎에서 가장 적었다. 무기질 함량은 Ca, Mg, Na, P, K가 높게 함유되어 있었고, 특히 K는 다른 원소들에 비해 매우 높은 함량을 나타냈으며($2580.88{\sim}3616.20$ mg%) 음건(SD)한 보리 잎 시료에서 가장 높아 무기질 성분이 매우 우수한 알칼리성 식품이라 사료된다. 또한 보리 잎의 유기산은 oxalic acid, acetic acid, citric acid, fumaric acid가 검출되었으며, 건조방법에 따라 각각 달랐다. 비타민 C 함량은 생엽(RL) 142.56 mg%, 열처리 후 건조(HD) 629.23 mg%, 음건(SD) 598.48 mg%, 동결건조(FD) 657.62 mg%, 전자레인지 건조(MW) 724.34 mg%으로 나타났고, 보리 잎은 무기질 외에도 비타민 C의 좋은 급원 식품임을 알 수 있었다. 본 실험의 결과 건조방법별 보리 잎의 성분에는 변화가 있었으며, 외관상 품질은 동결건조(FD)를 하였을 때 가장 좋았으나, 음건(SD)으로 시료를 처리하였을 때 각 성분의 파괴가 가장 덜 할 것으로 사료된다.

• 대한설비공학회지:설비저널
• /
• 제6권1호
• /
• pp.15-21
• /
• 1977

• 한국식품저장유통학회지
• /
• 제3권1호
• /
• pp.39-53
• /
• 1996

Ginseng, one of the important economic crops, is processed into medicine, teas, beverages and even foods. Drying is the most important and burdensome work in the processing of ginseng, so development of ginseng dryer is needed for efficient drying and good quality of ginseng. Investigation of drying model is essential for development of ginseng dryer. Drying models for peeled ginseng were investigated to determine dominant drying factors and fitted with five selected drying models and an empirical model. Thompson and the empirical model showed best fit with the experimental data. Pother experiment is necessary to prove the superiority of the empirical models.

• 한국기계가공학회지
• /
• 제21권9호
• /
• pp.35-41
• /
• 2022

The moisture content of many inorganic sludges is less than 70% during dewatering. Hence, a mono or piston pump cannot feed the sludge dryer. Thus, most inorganic sludge should be moved to a landfill or recycled directly without any reduction method. This development was invented to apply cyclone dryers using air and specially designed for the continuous injection of sludge sources by negative pressure and high air velocity for low moisture inorganic matter. Therefore, wastewater sludge and raw water treatment sludge discharged from various industrial fields might be settled by this development. The cyclone dryer was commercialized useful as moisture reduction equipment. This development was applied using a sludge injection system for sludge feeding and under the cooperation of ejector design computational fluid dynamics. Furthermore, this paper presented good ejector model results, blowing an airflow of 264 m³/min at an actual performance test.