• 한국작물학회지
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• 제36권4호
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• pp.345-350
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• 1991

본 연구는 건조온도 및 방법이 미곡의 품질에 미치는 영향을 검토하는 한편 추천온도 이상으로 고온건조되어 정조의 품질이 변화된 것들을 육안감정할 수 있는 방법을 찾아내고자 시도하였다. 농산물검사소에서 수집한 추청벼, 봉광벼, 화성벼를 공시하여 초기수분함량이 약 20%인 시료를 천일건조와 건조기의 온도 43, 60, 70, 8$0^{\circ}C$에서 수분함량 약 15%까지. 8$0^{\circ}C$의 경우에는 12.5%까지 과건조하여 미곡의 품위와 관련된 쌀의 외관 및 발아율을 조사하였고, 밥의 식미검정을 실시하여 건조온도에 따른 미곡의 품질 차이를 검토하였다. 그 결과를 요약하면 다음과 같다 1. 제현율은 건조온도가 높을수록 감소하였으며, 특히 8$0^{\circ}C$ 이상에서 현저히 감소하였고, 정백율은 화성벼가 추청과 봉광에 비해 낮은 경향이었으며 건조온도별로 유의한 차이는 있었으나 그 값은 8$0^{\circ}C$ 건조조건에서도 차이가 적었다 2 동할미 및 쇄미의 비율은 추청, 화성, 봉광벼 순으로 적었고, 피할립, 사미 및 착색미 비율이 10%미만(농산물검사기준의 현미 1등품기준) 인 건조조건은 천 일 건조와 43$^{\circ}C$건조였으며, 20%미만 (2등품기준)인 경우는 천일건조, 43$^{\circ}C$건조. 6$0^{\circ}C$건조에서였다. 한편 백미의 쇄미율이 정부관리쌀 기준인 5%이하에 적합한 건조조건은 천일건조와, 43$^{\circ}C$건조였다. 3. 발아율은 정상발아검정과 저온검정 모두에서 봉광. 추청, 화성벼 순으로 높았으며, 43$^{\circ}C$ 건조조건과 천일건조와는 큰 차이는 없었으나 이보다 높은 건조온도조건에서의 발아율은 현저히 감소하였다. 4. 현미의 백도는 추청, 봉광, 화성벼 순으로 높았으며 건조온도가 높을수록 증가하였다. 백미의 경우에는 봉광벼가 추청벼와 화성벼보다 높았으며, 8$0^{\circ}C$ 건조조건에서 유의하게 낮았다. 5 밥의 종합식미는 세품종 모두 기준인 천일건조 쌀보다 화력건조한 쌀의 평가치가 낮았으며 건조온도가 높을수록 낮았다. 6. 미곡의 품질은 현행 수분함량 측정과 기행하여 육안감정으로 동할미 및 쇄미 비율을 평가하는 것이 타당할 것으로 판단되었다.

• 태양에너지
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• 제11권3호
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• pp.21-30
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• 1991

곡물 bin을 이용한 벼의 건조실험을 수행하여 상온통풍건조 시스템과 태양열 건조 시스템의 건조 특성을 비교하여 분석하였다. 태양열 건조의 시뮬레이션 모형에 대한 컴퓨터 프로그램을 개발하였으며 시뮬레이션 모형에 의한 함수율의 예측치는 실측치와 전체적으로 일치하였다. 또한, inverter를 사용하여 벼의 건조 상태에 따라 송풍량을 적절하게 제어하는 송풍량 제어 시스템을 개발하였으며, 개발된 송풍량 제어 시스템을 통하여 에너지 절약 효과를 얻을 수 있었다.

• Journal of Biosystems Engineering
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• 제13권3호
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• pp.52-58
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• 1988

This study was conducted to develop a grain moisture content measurement sensor for automatic control of rough rice drying by natural air. For the above objective, the electrod type sensor was designed and tested. The sensor was able to produce electrical resistance which changes with moisture content of grain. An A/D converter and a micro-computer wed for processing measurement data of sensor. The developed sensor satisfied most design requirements and the results of statistical analysis show that there it no difference between the measurement method of sensor developed and of the dry-oven. Using the developed sensor and measurement system, we are able to measure moisture content of rough rice automatically in drying by natural air.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.863-877
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• 1996

A drying model to predict the drying process in continuous dryer was developed and proved by drying experiments. The experiment showed that the difference of moisture contents between the predicted and the observed was within 0.5%(wb). There was no cracked rice found even in high drying rate with the inlet moisture content over 23%(wb), and tempering treatment in the same temperature reduced the ratio of cracked rice. There was a little difference in the ratio of cracked rice between 40$^{\circ}C$ and 45$^{\circ}C$ drying temperatures with the final drying moisture content (14.5% wb), and the cracked rice increased at 55$^{\circ}C$. As a results, it was better to make fast drying on the rice over 23%(wb) inlet content it was recommended to keep drying at 45$^{\circ}C$.

• Journal of Biosystems Engineering
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• 제20권3호
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• pp.275-287
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• 1995

The rice processing complex(RPC) consisted of the rice handling, drying, storage, and milling processes. It has been established at 83 locations domestically by April 1994, and 200 of RPC will be built more throughout the country. Therefore, this study has been performed to achieve two objectives as the followings : 1) Development of mathematical models which can assess the requirement of electricity, fuel, and labor for four model systems of rice processing complex. 2) Development of a computer simulation model which produce the improved designs of RPC by the evaluation results of energy requirements of four RPC models. The results from this study are summarized as follows : 1) Mathematical models were developed on the basis of result of mass balance analysis and required power of machines for each process. 2) A computer simulation model was developed, which can produce the improved designs of RPC by the evaluation results of energy requirements. The computer simulation model language was BORLAND $C^{++}$. 3) The results of simulation showed that total energy requirements were ranged from 75.94㎾h/t to 124.30㎾h/t. 4) From the results of computer analysis of energy requirement classified by drying type, it was found that energy requirement of the drying type A{paddy rice (PR) for storage-natural air drying(15%), PR for milling-heated air drying(16%)} were less than that of the drying type B{1 step-natural air drying(PR for storage : 18%, PR for milling : 20%), 2 step-heated air drying(PR for storage : 15%, PR for milling : 16%)}. 5) The energy efficient drying method is that all the incoming rough rice to RPC should be dried by national air drying systems. If it is more than the capacity of national air drying system, the amount of surplus rough rice is recommended to be dried by the heated air drying method.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.957-966
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• 1996

An attempt was made to measure the availability of waste heat, released from the cooling system of a small engine, which can be utilized for grain drying. An engine powered flat-bed rough rice dryer was constructed and the performance of the dryer with available engine-waste heat was analyzed for 10 , 20, 30 and 40 cm rough rice bulk depths with a constant dryer base area of 0.81$m^2$/min. The waste heat was sufficient to increase the drying air temperature 7 to 12$^{\circ}C$ at an air flow rate of 8.8 to 5.7㎥/min, while the average ambient temperature and relative humidity were 24$^{\circ}C$ and 70%. The minimum energy requirement was 3.26 MJ/kg of water removed in drying a 40 cm deep grain bed in 14h. A forty to fifty centimeter deep grained seems to be optimum in order to avoid over-drying in the top layers. On the basis of minimum energy requirement (3.26 MJ/kg ) , an estimation was made that the waste heat harvest from an engine of a power range of 1 to 10.5PS can dry about 0.1 to 1 metric on of rough rice from 23% to 15% m.c. (w.b) in 12 h at an average ambient temperature and relative humidity of $25^{\circ}C$ and 80%, respectively. The engine-waste heated grain dryer can be used in the rural areas of non industrialized countries where electricity is not available.

• 한국농공학회지
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• 제17권1호
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• pp.3677-3684
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• 1975

A newly devised dryer with heated air for the farm products, especially suited for high water content materials such as red pepper, Beer ground, each Vegetables, and Low water content materials such as Rough rice was tested for its thermal efficiency and drying mechanism, and the optimum conditions for each sample were established. In order to improve the present rural situation of drying farm products which entirely dependent upon natural solar radiation, a study upon an economic multi-parpose dryer was conducted. A series of drying tests were run first with red pepper which is one of the important cash crop in Korean farm. And successive series of tests were also run with such proaucts as garlic, sweet potatoes, green onion, radish, Beer ground and Rough rice. The results from the above experiment in drying system with heat dryer can be summarized as follows. 1. Drying duration could be shortened by the tempering effect in high water content crop such as red pepper and beer ground. 2. The color changes occured in around 20% water content in red pepper. The degree of color change was heavily affected by high temperature and short drying duration. 3. The drying condition of red pepper was most favourable at the temperature of 85$^{\circ}C$ in early stage and 80$^{\circ}C$ in middle stage and 75$^{\circ}C$ at the final stage, and with the air rate of 0.81㎥/sec and with sample amount of 200kg. 4. The drying condition of Rough rice(I.R.667) was most favourable at the templature of 40$^{\circ}C$ in early stage and 35$^{\circ}C$ in middle stage and final stage and with the air rate of 0.2㎥/sec and with sample amount of 75kg. 5. In order to prevent the color change of red pepper and to assure high efficiency in drying mechanism, it was necessary to lower the temperature as the time passes in drying process. 6. For vege tables, the drying rate were short in early stage and there was also tempering effect. However, for garlics, Constant drying rates through the early and final stages were observed and there were no tempering effects. 7. The drying condition or capability were as follows; Sample drying temp($^{\circ}C$) amount of material(kg) drying time(hr) Red pepper 85 200 9 Garlic 85 150 7 Sweet potato 85 200 6 Green Onion 85 200 4 Carrot 85 200 4 Radish 90 250 4 Rough rice(I.R.667) 35 75 4 Beer ground 90 320 3 Considering the above result of experiments, if this kind of dryers were distributed Korean farm and the optimun process were practiced in rural area, it would certainly help them improving the qualites of their product preventing their undue losses, and thus assuring an increase of Korean farm income and promotion of their living standards.

• 한국식품저장유통학회지
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• 제16권5호
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• pp.650-655
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• 2009

용량 150 kg의 실험용건조기와 heat pump를 이용하여 건조온도 20, 30, 40 및 $50^{\circ}C$에서 건조실험을 수행하였다. 건조과정에서 함수율, 동할율의 경시적 변화와 건조 전 후의 발아율 및 식미를 측정하여 저온건조과정에 벼의 품질과 적정 건조온도를 구명하였다. 건조온도 20, 30, 40 및 $50^{\circ}C$에서 건조속도는 0.3, 0.6, 0.9 및 1.3%/hr 로 건조온도가 높을수록 건조는 빠르게 진행되었으며, 건조온도 $40^{\circ}C$ 이상은 고온영역, 그 이하는 저온영역으로 구분할 수 있다. 동할율은 건조온도 $20^{\circ}C$에서는 발생하지 않았고 건조온도 30, 40 및 $50^{\circ}C$에서 1.6, 6.8 및 24.2%로 나타나 건조온도가 높을수록 동할 발생이 증가하였다. 따라서, 건조온도 20 및 $30^{\circ}C$는 동할율 기준치에 적합한 안전한 온도영역이며, $50^{\circ}C$는 매우 위험한 온도영역으로 판단된다. 또한, 건조온도 $40^{\circ}C$는 동할율 방지를 위해 템퍼링시간 증대 등 운영방법의 조정이 필요하였다. 건조온도가 높을수록 건조후 발아율은 저하하였으며, 건조온도 20 및 $30^{\circ}C$에서 발아율은 종자용으로 사용가능한 영역이었으며, 건조온도 40 및 $50^{\circ}C$는 최소 영역인 80%에 만족하였다. 식미관능검사에서전반적인(Overall) 품질, 외관(Appearance)의 품질, 맛(Taste)의 품질 및 조직감(Texture)의 품질에서 유의적인 차이가 나타났으며, 종합적으로 판단해볼 때 건조온도 $20^{\circ}C$와 $30^{\circ}C$에서 식미가 높게 나타났으며, 건조온도가 가장 높은 $50^{\circ}C$에서는 상대적으로 낮게 나타났다. 따라서, 품질이 우수한 건조조건은 건조온도 $30^{\circ}C$ 이하, 건조속도 0.6%/hr 이하를 유지하는 것이 적정한 것으로 판단된다.

• Journal of Biosystems Engineering
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• 제32권5호
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• pp.309-315
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• 2007

This study was performed to develop a simulation model of circulating concurrent-flow rice dryer. The simulation model consists of drying model, tempering model and crack prediction model. The drying and tempering models were developed based on mathematical analysis, and the crack prediction model was developed by thin layer drying tests. Rice drying tests were done with three replications by use of a pilot scale dryer of holding capacity of 700 kg. Experimental values for moisture content, rice temperature, rice crack, and drying energy were compared with predicted values by simulation model. The RMSEs of predicted moisture contents were ranged from 0.5807% (d.b.) to 1.1951% (d.b.). and the coefficients of determination were 0.9688 to 0.9812. The RMSEs of predicted rice temperatures at the exit of the drying chamber were 1.83 to $3.81^{\circ}C$ and the coefficients of determination were 0.8834 to 0.9482. The results for moisture contents and rice temperatures showed very good relationships between predicted values and experimental values. The RMSEs of predicted value of crack ratio were 0.4082 to 0.7967% and the coefficients of determination were 0.8742 to 0.9547.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.405-412
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• 2000

A natural air in-bin grain dryer with a grain circulator was developed for on farm use. Natural air drying test for rough rice was carried out to evaluate drying rate, uniformity of moisture content distribution in grain bed and energy consumption. It took 10 days to dry 8 ton of paddy rice from 21.9%(w.b) to 16.7%(w.b) moisture contents using the prototype dryer. The average drying rate was 0.52%/day. The uniformity of moisture content after drying was superior to the conventional natural air dryer where is grains were not circulated during drying periods. The dryer performance evaluation index was 738.3KJ/(kg.water), which was more effective than that of grain circulation t)pe hot air dryer(3,500-5,000 KJ/kg.water).