• 한국가스학회지
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• 제20권6호
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• pp.43-49
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• 2016

전 세계적인 천연가스 저열량화 추세에 따라 우리나라 천연가스 열량 기준이 기존의 표준 열량제에서 보다 유연한 열량범위제로 개선되었다. 이 같은 변화는 가정이나 산업체 전반에 걸쳐 가스기기 성능에 직접적인 영향을 미치기 때문에 이를 규명하고자 하는 연구가 필요하다. 특히 열병합 발전용 엔진으로 사용되는 디젤-CNG 혼소엔진의 경우 도시가스를 주 연료로 사용하기 때문에 발열량 변화는 발전 사업자의 수익성 확보와 연관되는 중요한 사안이다. 따라서 본 연구에서는 열량범위제 내에서 허용하는 CNG 발열량 변화가 디젤-CNG 혼소엔진의 배기특성에 주는 영향에 대해 조사하였다. 도시가스 발열량 변화를 모사하기 위해 열량 범위 상한선인 $10,400kcal/Nm^3$의 CNG 연료에 질소를 희석시켜 발열량을 $10,400kcal/Nm^3$에서 $9,400kcal/Nm^3$까지 변경하였다. 혼소율 80% 조건에서 디젤 연료 분사 시기는 16 CAD BTDC, 분사압력은 110 MPa로 고정하고 엔진회전수 및 토크는 1800 rpm/500 Nm으로 설정하여 시험을 수행하였다. 엔진시험 결과 발열량이 감소할수록 불완전연소가 증가하여 THC, $CH_4$ 및 CO 배출량은 증가하는 반면 NOx 배출량은 감소함을 확인하였다. 그리고 이 같은 결과를 바탕으로 배기 특성 변화에 대해 대응할 수 있는 방안에 대해 고찰하였다.

• 신재생에너지
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• 제9권4호
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• pp.40-50
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• 2013

This study was performed to investigate the potential of torrefied tulip tree (TT) for the production of pellets. For this purpose, chemical composition and fuel characteristics of torrefied TT were examined. In addition, pellets were fabricated by using sawdust of torrefied TT chip, and durability of the pellet was measured. Lignin content of torrefied TT was higher than that of non-torrefied TT, and increased with the increases of torrefaction temperature and time. Fuel characteristics of torrefied TT were affected by torrefied conditions, and the characteristics were influenced more by torrefaction temperature than by torrefaction time. Higher heating value (HHV) and ash content (AC) of torrefied tulip tree increased with increasing torrefaction temperature, and the values were much higher than HHV and AC values of non-torrefied TT. Durability of pellets fabricated with $230^{\circ}C$- and $250^{\circ}C$-torrefied TT was higher than that of $270^{\circ}C$-torrefied TT, and the value exceeded the minimum requirement (-97.50%) of the 1st-grade pellet standard designated by Korea Forest Research Institute. Based on the results, torrefaction treatment of $250^{\circ}C/50min$ to TT might be a optimal condition for the production of TT pellets considering the mass balance and fuel characteristics of TT as well as the durability of the pellets. Thus, it is confirmed that torrefied TT can be used as a raw material for the production of bio-pellets.

• 동력기계공학회지
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• 제19권4호
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• pp.69-75
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• 2015

In this study, the characteristics of heating performance of a high-performance air-cooled heat pump with vapor-injection(VI) cycle using re-heater was investigated experimentally. Devices used in the experiment is consist of a VI compressor, condenser, oil separator, refrigerant (economizer outlet refrigerant) re-heater, economizer, evaporator. And R410A was used as a working fluid. The experiment was conducted with two cycles(cycles A and B) for investigating heating performance. In case of cycle B, heat exchange was conducted by re-heater between outlet refrigerant of compressor and suction refrigerant of the VI system(Fig.1, re-heater). But the re-heater was not used in case of cycle A. As a result of this experiment, discharge temperature of refrigerator in compressor was shown higher value, when the cycle B was conducted, because of the heat exchange between suction refrigerant of VI cycle and outlet refrigerant of compressor in the re-heater than cycle A that was not use re-heater. it means that liquid hammer and the decrement of heating performance can be decreased by using re-heater. Also, Heating coefficient of performance(COPh) was shown about 2.98 in Cycle B which was 4% higher than Cycle A and from these results, It was confirmed that the improvement of the heating performance of heat pump with VI cycle can be achieved by applying re-heater.

• 한국염색가공학회지
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• 제30권3호
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• pp.216-226
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• 2018

The combination dyeing have been attempted to get the various color. The objective of this research was to study the color developing effects on cotton fabrics dyed with persimmon, catechu and combination of the both by heat treatment process. These dye were applied on bleached cotton fabrics for the dyeing before post mordanting with aluminium potassium sulfate, copper sulfate, and iron sulfate. The various color changes on cotton fabric were measured by color spectrophotometer. The heat treatment of temperature around $150^{\circ}C$ for an hour can reach the highest color developing. The dyed fabrics with mordanting were heated for specific time period, which was compared without the mordanting. The post mordanted fabrics showed that more various colors can be obtained using combination dyeing. K/S values of dyed fabrics with Al, Fe, and Cu mordants were higher than the cases without mordants. The Cu mordanted fabric showed very effective color developing by the heating process. The fabrics dyed with catechu lowered L* value with little changes in a* and b* values, while the a* and b* values became higher with heat treatment. The fabrics dyed with persimmon has the lowest L* value and more changes in a*, b* value with heating process. Therefore, K/S values can be increased effectively by the combination dyeing of persimmon and catechu. Colorfastness to washing in color change was grade 2-3 in non-mordanted fabric, and grade 3 in mordanted fabric. Lightfastness of the dyed fabrics was above grade 4.

• 농업과학연구
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• 제38권4호
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• pp.619-624
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• 2011

The calorific value is the most significant factor in woody biomass utilization. We measured the calorific value by the wood parts (debarked parts and bark) and moisture content for 3 major tree species (Larix kaempferi, Pinus koraiensis, and Pinus rigida). Results showed that the calorific value decreased exponentially as the moisture content increased regardless of tree species and the wood parts. The bark had higher calorific values than woody parts (de-barked parts). In addition, Pinus koraiensis had the highest calorific values among 3 study species.

• 수산해양기술연구
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• 제44권4호
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• pp.362-369
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• 2008

The snow melting system by electric heating wires which is adopted in this research is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, installation place and each country applying the system. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitch for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating wires(200 mm, 300 mm), heating value($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• 한국식품영양학회지
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• 제16권2호
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• pp.130-137
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• 2003

The squid had not been utilized for gel products because of its lower gel forming ability. The objectives of this study were as followed; 1) the optimum heating condition on squid meat paste products and 2) the optimum added level for jelly strength of squid meat paste products. Optimum heating conditions of squid meat kamaboko were as followed; setting(pre-heating) at 15$^{\circ}C$ or 55$^{\circ}C$ for 2 hours and heating at 9$0^{\circ}C$ for 60 minutes. The additives examined were as follows; 20mM EDTA, 10mM PMSF, 5 $\mu$mol/100g TGase, 0.2% potassium bromate, 2% collagen, 2% sucrose ester of stearic acid and 1% egg shell powder. The effects of additives on jelly strength were observed as follow, in descending order; 10mM of PMSF>5 $\mu$mo1/100g of TGase>0.2% of potassium bromate>20mM of EDTA. But sucrose ester of stearic acid and 1% egg shell powder were no effect. The solvents examined were as follows; n-amyl alcohol, n-butyl alcohol, n-hexyl alcohol, ethyl alcohol, ethylene glycol, propylene glycol and glycerin glycol. It showed that high jelly strength as 787gㆍcm for 3% of n-butyl alcohol and 749gㆍcm for 3% of n-amyl alcohol. To adding 5% of n-butyl alcohol and n-amyl alcohol, gave the highest jelly strength and water holding capacity(WHC). Effect of alcohol on jelly strength appeared higher value at added 5% of n-butyl alcohol than n-amyl alcohol, and flying squid product was higher than jumbo squid product.

• 한국식품과학회지
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• 제43권6호
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• pp.711-718
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• 2011

들깨의 가압가열 처리 중 들깨지방질의 산화정도와 토코페롤 및 폴리페놀 화합물의 분해는 들깨의 볶음 여부와 가열 조건에 따라 차이가 있었다. 가압가열 처리 중 볶은 들깨보다 생 들깨에서 지방질 산화 안정성은 높았으나, 산화방지제의 안정성은 낮았다. 또한 토코페롤보다는 폴리페놀 화합물이 들깨의 가압가열 중 지방질산화에 기여한 정도가 더 높았다. 그러므로 들깨를 들깨죽 제조에 적용할 때 폴리페놀 화합물의 농도와 안정성을 개선할 수 있는 방법을 모색함으로써 보다 높은 품질의 들깨 적용 식품을 생산하는데 도움이 될 것이다.

• 유기물자원화
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• 제15권1호
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• pp.134-142
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• 2007

본 연구는 생활쓰레기의 물리 화학적 분석 및 발열량 등으로 그 특성을 알고 반응기를 이용한 열중량감량 분석을 함으로써 열처리 시설의 가장 효율적인 운영에 기초자료가 됨을 목적으로 한다. 측정 결과는 다음과 같다. 쓰레기의 삼성분 중 가연분이 약 61%로 다른 수분(약 32%) 회분(약 7%)보다 함유량이 높았고 쓰레기의 원소분서결과 종류에 관계없이 탄소와 수고(약 94%)의 존재량이 대부분이었다. 쓰레기의 발열량 분석 결과 고위발열량은 2897.883(Kcal/kg)의 값을 갖는 것으로 나타났다. TGA를 이용하여 도시 생활쓰레기의 종류별 열적 특성을 분석한 결과 온도가 증가함에 따라서 시로 중에 함유된 휘발분이 지속적으로 무게 감량이 일어났으며 특히 $300{\sim}500^{\circ}C$에서 열중감량이 활발히 진행되고 그 반응속도에 차이가 있음을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제34권3호
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• pp.15-21
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• 2006

목질펠릿을 탄화하여 탄화물의 이용가능성을 알아보기 위하여 밀도, 수율, 원소조성, 발열량, 메틸렌블루흡착량 등의 특성을 분석하였다. 목질펠릿은 현사시, 일본잎갈나무, 잣나무, 소나무, 졸참나무의 수피를 포함한 톱밥을 이용하여 제조하였다. 목질펠릿으로부터 $0.5{\sim}0.7g/cm^3$의 고밀도 탄화물을 얻을 수 있었으며, 탄화온도가 증가하면 탄화물의 탄소함량과 발열량이 증가하였다. 목질펠릿으로부터 얻어진 탄화물의 메틸렌블루 흡착 특성은 목재의 것과 거의 유사하였다.