• 한국수산과학회지
• /
• 제21권1호
• /
• pp.16-20
• /
• 1988

다시마의 건조와 수축특성을 알기위한 기초자료를 얻고자 건조중인 다시마의 건조 및 수축특성에 미치는 채취부위, 공기의 온도, 상대습도 및 풍속의 영향에 관하여 실험한 결과를 요약하면 다음과 같다. 1) 다시마의 열풍건조과정은 항률건조 기간이 없이 바로 감률건조기가 나타났으며 이것은 다시 감률건조 1단계 및 2단계로 구분되었다. 2) 두께가 얇은 선단부가 기부보다 수축이 더 많이 되었으며 공기의 온도 $50^{\circ}C$, 상대습도 $30\%$, 유속 0.4m/s의 일정한 건조 조건하에서 다시마의 선단부, 중간부 및 기부를 120분까지 건조하였을 경우 수축율은 각각 $57.5\%,\;54.0\%,\;42.7\%$이었다. 3) 상대습도가 낮은것은 높은것에 비해 건조속도 및 수축속도는 빨랐으나 함수률 $20\%$까지 건조하였을 경우 수축율은 오히려 상대습도가 높은것이 증가하였다.

• 분석과학
• /
• 제10권6호
• /
• pp.418-426
• /
• 1997

고주파를 이용한 오니의 건조특성에 대하여 살펴보고 재래식 건조특성과 비교 분석하였다. 고주파 건조는 빠른 속도와 높은 효율을 보였다. 재래식 건조에서는 항율건조기간이 나타나지 않았고 수분은 모세관현상에 의하여 이동하였다. 오니의 수분 중 자유수와 결합수는 존재하지 않았다. 고주파 건조에서 감율건조기간이 두 부분으로 나타났으며, 수분의 이동은 확산에 의하여 일어났다. 증발 표면적이 커질수록 수분의 제거가 촉진되었고, 오니의 지름이 커질수록 넓은 범위의 항율건조 기간이 나타났으며, 모양에 따라서도 건조특성이 다르게 나타났다. 고주파 건조에서는 오니의 중심부에서 가장 먼저 온도가 상승하였으며, 항율건조기간에서 $80{\sim}100^{\circ}C$로 일정하게 유지되면서 가장 높았다.

• 한국식품저장유통학회지
• /
• 제2권1호
• /
• pp.155-161
• /
• 1995

We examined the drying characteristics and the drying rate model equation of garlic(allium sativum L.) using computer aided convective drying. The drying chanacteristic curve of garlic divided into constant rate drying period and 2 stage of falling rate drying period. The drying rate was fairly affected by hot air temperatures during the total drying period, but air flow rates has nearly no effect on the drying rate except initial drying period. Of the several model equation, r2 values of page model equation was the highest, and the estimated drying profiles were comparatively coincided with the observed drying profiles. Page model equation was suitable to predict the drying rate and moisture content during drying of sliced garlic.

• Food Science and Biotechnology
• /
• 제18권1호
• /
• pp.202-206
• /
• 2009

Drying characteristics of fresh Korean-type rehmannia (jiwhang) noodle was investigated to determine drying kinetic parameters under the experimental conditions of 5 temperatures (30, 40, 60, 80, and $90^{\circ}C$). Drying curve of the noodle showed a biphasic pattern of decrease in drying rate with initial rapid drying followed by slow dehydration as the progress in drying. In all drying conditions, only falling drying rate period was observed and the drying rate of the noodle was greatly influenced by the drying temperature. The effective diffusion coefficients ($D_{eff}$) were determined by the diffusion model and their temperature dependency was determined using an Arrhenius equation. The activation energy ($E_a$) values for the drying of the noodle were 19.94 and 21.09 kJ/mol at the initial and the latter stage of dehydration, which were comparable to those of pasta or Japanese udong dehydration.

• 동력기계공학회지
• /
• 제15권3호
• /
• pp.46-51
• /
• 2011

Low temperature vacuum drying technique, whose drying time and quantity of exhausting energy is about 25~30% of hot air drying, is very excellent in the drying efficiency. This paper is made out in the aspects of heat engineering with the object of developing Korean drying machine which can dry once a large quantity of objects to be dried in the state of low temperature and vacuum. As the results, it took about 17 hours(3~4 days in case of hot air drying) for material to reach about 18% of the final moisture content in order to store products for a long time, from about 78~80% of the early moisture content at the beginning of drying, and maximum drying rate comes to about 0.35 kg/m2hr at about 400% of the moisture content.

• 환경위생공학
• /
• 제13권1호
• /
• pp.9-15
• /
• 1998

Microwave heating and drying processes have been well established in various industrial applications. Feasibilities of successful application of microwave drying to many material have been shown on the laboratory or pilot-plant scale. The microwave drying behavior of plating sludge are considered in this paper. The plating sludge containing 70%, 80% and 90% water exposed to microwave power at 2,450 MHz, 700W. An experimental microwave drying apparatus was designed and constructed to monitor weight loss during drying. By studying the drying characteristic curve, the moisture in sludge was almost classified into two categories : free moisture and intestinal moisture. And the critical moisture contents at which the drying rate ceases to be constant were from 10.1 to 10.5%. A simple drying model is proposed which may be used to describe drying behavior of plating sludge. The constant rate and the falling rate periods in microwave drying were addressed separately. From the eqation of constant rate period the drying rate constants decreased exponentially with increasing depth. Microwave heating compared with conventional heating offered higher heating rates from 9 to 16 times. Therefore, microwave drying process can be effective in removing moisture from plating sludge.

• Journal of Advanced Marine Engineering and Technology
• /
• 제26권2호
• /
• pp.226-232
• /
• 2002

In tradition, there have been two kinds of drying methods, which are sun drying and artificial drying. The sun drying method which has been adopted traditionally has been replaced by the hot-air drying method which is one of the most general methods of artificial drying, with its simple drying system, low initial cost of drying plant, and easy operating method. But the hot-air drying method has some defects ; (1)much energy loss happens due to the discharge of hot air during the drying process, (2)control of drying rate is not easy on account of changing relative humidity of inlet air for uniform hot air temperature, (3)high temperature of floods in drying process brings about the production of low-grade drying products. Also, the hot-air drying method is inducing environmental and sanitary problems which are resulting from the emission of high temperature and high humidity air, including stick on the drying progress. Vacuum drying technique, whose drying time and 7uantity of exhausting energy is about 1/3 ~1/4 of hot air drying, is very excellent in the drying efficiency. As the results, it took about 20 hours for material to reach about 18% of the final moisture content in order to store products for a long time, from about 470% of the early moisture content at the beginning of drying, and maximum drying rate comes to about $0.35 kg/m^2hr$ at about 350% of the moisture content.

• Applied Biological Chemistry
• /
• 제17권1호
• /
• pp.42-48
• /
• 1974

고추 건조방법(乾燥方法)의 개선(改善) 및 건조특성(乾燥特性)을 알기 위하여 원형(原形) 및 절단(切斷)고추에 대(對)하여 온도(溫度)및 풍속(風速)의 영향을 조사(調査)하고 고추 건조기작(乾燥機作)을 고찰(考察)하였다. 1) 원형(原形)고추 건조곡선(乾燥曲線)의 특징(特徵)은 건조초기(乾燥初期)에는 어느정도(程度)의 settling down period를 가졌고 그이 후 제일(第一), 이기(二期) 감율건조기(減率乾燥期)를 보였으나 저온건조(低溫乾燥)일수록 항속건조양상(恒速乾燥樣相)을 띠어 임계수분함량(臨界水分含量)에 이르는, 시간(時間)이 최저온도(最低溫度)인 $55^{\circ}C$에서 15시간(時間)이나 되었다. 2) 절단(切斷)고추의 건조곡선(乾燥曲線)에서는 건조속도(乾燥速度)의 변화(蠻化)가 급격(急激)하였다. 3) 절단(切斷)고추의 건조방법(乾燥方法)은 원형건조(原形乾燥)에 비해 보다 효과적(效果的)이어서 각(各) 건조온도(乾燥溫度)에서 모두 약(約) 2배(倍) 이상(以上)의 건조시간(乾燥時間)을 단축(短縮)할 수 있었다. 4) 원형(原形) 및 절단건조(努斷乾燥) 모두 건조속도상수(乾燥速度常數)(k)값은 일정(一定)하지않고 시간(時間)에따라 변화(變化)하였으나 양건조방법(兩乾燥方法)에서 k값의 시간(時間)에 대(對)한 변화양상(變化樣相)이 구별(區別)되었다. 5) 건조속도상수(乾燥速度常數) k 값을 일정(一定)한 평균치(平均値)로 택(擇)할 경우, 원형건조(原形乾燥)에 대(對)하여는 $M-M_e/M_o-M_e=e^{-0.118t}$식(式는)이 절단건조(切斷乾燥)에 대(對)하여는 $M-M_e/M_o-M_e=e(-0.342t^{0.128})$식(式)이 적용되었다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제24권4호
• /
• pp.427-434
• /
• 2000

In tradition, there have been two kinds of drying methods, which are sun drying and artificial drying. The sun drying method which has been adopted traditionally has been replaced by the hot-air drying method which is one of the most general methods of artificial drying, with its simple drying system, low initial cost of drying plant, and easy operating method. But the hot-air drying method has some defects; (1) much energy loss happens due to the discharge of hot air during the drying process, (2) control of drying rate is not easy on account of changing relative humidity of inlet air for uniform hot air temperature, (3) high temperature of foods in drying process brings about the production of low-grade drying products. Vacuum drying takes advantage of energy saving and mass production because it reduces the drying time by increasing the drying rate under low temperature condition. The aim of this paper is to develop the low temperature vacum dryer, with low initial investments and operating costs, easy operating method and trouble-free operation.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권3호
• /
• pp.588-594
• /
• 2001

The aim of this paper is to develop the low temperature vacuum dryer, with low initial investments and operating costs, easy operating method and trouble-free operation Usally operations just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressure as low 50 mmHg abs. The lowers the boiling point to $39^{\circ}C$ The experimental data of quantitative analysis for using practically were obtained by the constant drying rate period and reducing drying rate period according to the temperature of hot water which is the experimental parameters of present experiment. As the results, it took about 20 hours for material to reach about 18% of the final moisture content is order to store products for a long time about 450% of the early moisture content at the beginning of drying and maximum drying rate comes to about 0.30 kg/m2hr at about 350% of the moisture content.