• 한국자동차공학회논문집
• /
• 제22권5호
• /
• pp.116-125
• /
• 2014

Pyrolysis oil (PO), derived from biomass through fast pyrolysis process have the potential to displace significant amounts of petroleum fuels. The PO derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, the use of PO in a diesel engine is very limited due to its poor properties like low energy density, low cetane number, high acidity and high viscosity of PO. Therefore, one of the easiest way to adopt PO to diesel engine without modifications is blended with other fuels that have high centane number. However, PO that has high amount of polar chemicals is immiscible with non polar hydrocarbons of diesel or biodiesel. Thus, to stabilize a homogeneous phase of diesel/biodiesel-PO blends, a proper surfactant should be used. Nevertheless, PO which was produced from different biomass type have varied characteristics and this complicates the selection of a suitable additive for a specific PO-diesel emulsion. In this regard, a more simple approach such as the use of a co-solvent like ethanol or butanol to induce a more stable phase of the PO-diesel mixture could be a promising alternative. In this study, a diesel engine operated with diesel/biodiesel-PO-butanol blends was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine were examined under the engine loads of IMEP 0.2 ~ 0.8MPa.

• Journal of Ecology and Environment
• /
• 제36권1호
• /
• pp.31-38
• /
• 2013

Annual ring formation is considered a source of information to investigate the effects of environmental changes caused by temperature, air pollution, and acid rain on tree growth. A comparative investigation of annual ring growth of Cryptomeria japonica in relation to environmental changes was conducted at two sites in southern Korea (Haenam and Jangseong). Three wood disks from each site were collected from stems at breast height and annual ring growth was analyzed. Annual ring area at two sites increased over time (p > 0.05). Tree ring growth rate in Jangseong was higher than that in Haenam. Annual ring area increment in Jangseong was more strongly correlated with environmental variables than that in Haenam; annual ring growth increased with increasing temperature (p < 0.01) and a positive effect of $NO_2$ concentration on annual ring area (p < 0.05) could be attributed to nitrogen deposition in Jangseong. The correlation of annual ring growth increased with decreasing $SO_2$ and $CO_2$ concentrations (p < 0.01) in Jangseong. Variation in annual growth rings in Jangseong could be associated with temperature changes and N deposition. In Haenam, annual ring growth was correlated with $SO_2$ concentration (p < 0.01), and there was a negative relationship between precipitation pH and annual ring area (p < 0.01) which may reflect changes in nutrient cycles due to the acid rain. Therefore, the combined effects of increased $CO_2$, N deposition, and temperature on tree ring growth in Jangseong may be linked to soil acidification in this forest ecosystem. The interactions between air pollution ($SO_2$) and precipitation pH in Haenam may affect tree growth and may change nutrient cycles in this site. These results suggested that annual tree ring growth in Jangseong was more correlated with environmental variables than that in Haenam. However, the further growth of C. japonica forest at two sites is at risk from the long-term effects of acid deposition from fossil fuel combustion.

• 한국생활과학회지
• /
• 제12권1호
• /
• pp.85-94
• /
• 2003

With 106 detached houses where the elderly people lives, this study was conducted to perform a survey of their residential environment. The results of this study were summarized as follows: While the surveyed houses' safety, sanitation and convenience appeared to be positive, with respect to the conditions of location, 73.6% of the surveyed houses did not meet the requirements for comfort. The average area of each space indicated that the bed room was $12.09m^2$, the living room $14.38m^2$, the kitchen $8.96m^2$, the bath room $3.93m^2$, and the rest room $259m^2$. Then, 93.3% of the bed room had the doorsill. Also, 97.2% of the surveyed houses had retrievable space. The forms of the living room door were a hinged door(55.7%) and a sliding door(44.3%). The 43.4% of the finished material of the living room was wood which was highest. The cooking table forms of kitchen were mainly "ㄱ"-shaped(50.0%) and "ㅡ"-shaped(48.0%), and their average height was 815mm. The fuel used for kitchen was mainly the gas which accounted for 93.4%, but 95.3% of houses had no gas-warning devices. Most houses(77.4%) had an integrated type of bathroom and toilet. In addition, 63.2% houses had the stepped difference between the bathroom and other spaces. But they had no a sliding-prevention devices(not for 92.5%) or heating systems(not for 93.4%) in the bathroom.

• 유기물자원화
• /
• 제16권1호
• /
• pp.79-88
• /
• 2008

지구온난화에 따른 대체연료의 하나로 바이오에탄올의 생산이 증대되면서 곡물가격 상승과 같은 문제를 야기하고 있다. 차세대 바이오에탄올의 원료로서 목질계 바이오매스는 큰 잠재성에도 불구하고 높은 생산단가로 인하여 상업화 되지는 않고 있다. 생산단가의 절감을 위해 필요한 핵심기술은 가수분해율을 높이고 단당의 회수율을 높이는 것으로 전체 바이오에탄올 생산공정에서 열화학적 전처리이다. 본 연구에서는 목질계 바이오에탄올 제조공정에서의 열화학적 전처리에 대하여 소개하고 극복해야 할 문제들에 대하여 제시하고자 한다. 산, 알칼리, 열수, 용매, 암모니아, 산소 등을 첨가하는 전처리는 리그닌과 헤미셀룰로오스를 제거하고 셀룰로오스의 결정성을 감소시킨다. 이러한 전처리 방식들은 침엽수, 활엽수, 곡식의 줄기 등 목질계 원료에 따라 최적의 처리 조건들이 확립되어져야 한다.

• 에너지공학
• /
• 제25권4호
• /
• pp.214-225
• /
• 2016

목재 바이오매스를 이용한 가스화 공정은 고열량의 합성가스를 통해 알콜류, SNG 등 다양한 에너지 자원으로 변환시킴으로써 자원의 재순환에 기여할 수 있으며, $CO_2$ 등의 온실가스를 감소시킴으로써 지구온난화 방지에 기여할 수 있다. 본 연구에서는 이중유동층 가스화기에 목재 바이오매스를 투입하여 가스화기의 최적운전 조건을 도출하고, SNG 생산효율을 검증함으로써 이중유동층 가스화기에 대한 국내 상용화 기반을 마련하고자 하였다. 목재 바이오매스에 대한 가스화기의 최적 운전조건 도출 결과, 운전온도 $826^{\circ}C$에서 Steam 투입량 1,334g/hr, Air 투입량 5.56L/min일 때 탄소전환율이 81%로 확인되었으며, SNG 생산을 위한 $CH_4$가스 농도를 확인한 결과, 92%로 나타났다.

• Journal of Forest and Environmental Science
• /
• 제31권4호
• /
• pp.241-254
• /
• 2015

This study attempts to examine farmers' preference and perception towards cropland agroforestry (CAF) and its economic benefits in Bangladesh. It surveys 84 farmers of two sub-districts named Manirampur and Bagherpara under Jessore district of Bangladesh to address the study objectives with the help of a questionnaire during the period of June to July 2013. We follow a multistage random sampling procedure for selecting respondents of the survey. A total of 27 plant species under 19 families are identified in the surveyed crop fields, among which 11 are tree species and 1 is shrub from 8 families and 15 species are agricultural crops from 11 families. According to the survey findings, most of the farmers prefer multipurpose tree species like Swietenia macrophylla (67 percent), Phoenix sylvestris (48 percent), Mangifera indica (48 percent) and Cocos nucifera (43 percent). We also find that Curcuma longa (92 percent), Oryza spp. (56 percent), Solanum melongena (43 percent) and Amorphophallus campanulatus (33 percent) are the available agriculture crops which are grown in association with trees in the study area. The surveyed farmers report that they practice CAF to get fuel wood, fodder, juice, fruit and food for family consumption and revenue earnings. About 76 percent of the surveyed farmers endorse the existence of a positive interaction between trees and agriculture crops, while the rest 24 percent endorse the existence of a negative interaction between trees and agriculture crops. This study finds that CAF farmers on an average earn US$ 1,410 per farm per year and the yearly average revenue difference between CAF and non-cropland agroforestry (NCAF) farmers is US$ 214. Overall, CAF needs to develop through scientific intervention in the study area to conserve the biodiversity and to enhance farmers' sustainable livelihood.

• 한국수소및신에너지학회논문집
• /
• 제28권6호
• /
• pp.683-690
• /
• 2017

Wood pellet (WP), empty fruit bunch (EFB) and palm kernel shell (PKS) which are biomass fuels for power generation are selected to study the characteristics of torrefaction process. These biomass fuels are torrefied at $220^{\circ}C$, $250^{\circ}C$, and $280^{\circ}C$. The heating value of biomass fuels is increased depending on the torrefaction temperature. However, due to energy yield decline, it is not always desirable to torrefy biomass at higher temperature. Considering the mass yield and energy yield after torrefaction, the most proper temperature conditions for torrefaction of WP is $250-280^{\circ}C$ and for EFB, PKS are $220-250^{\circ}C$. Additionally, to investigate the phenomenons of chlorine release during torrefaction process, Ion Chromatography (IC) method was used. In the case of EFB and PKS torrefied at $300^{\circ}C$, the chlorine component has been reduced by 97.5% and 95.3% compared to the raw biomass, respectively. In conclusion, torrefied biomass can be used as alternative fuels in replacement of coals for both aspects of heating value and chlorine corrosion problems.

• 유기물자원화
• /
• 제16권3호
• /
• pp.65-74
• /
• 2008

본 연구에서는 서로다른 4지역의 도시 생활 쓰레기의 성상 및 물리 화학적 조성을 조사 하였다. 생활 쓰레기 연료화시설 설치 및 자료확보 차원 매립장 관리차원에서 매우 필요한 연구이다. 평균 밀도는 $79{\sim}199.8kg/m^3$ 범위내의 결과를 얻었다. 생활 쓰레기는 8.87%의 음식물류, 38.8%의 종이류, 34.12%의 플라스틱류 및 비닐류, 7.16%의 섬유류, 0.96%의 목재류 1.3%의 고무 및 가죽류 등으로 구성되어 있다. 생활쓰레기의 대부분은 음식물, 종이류, 플라스틱류 등으로 이루어져 있으며 94% 정도가 가연 성분이다. 삼성분 분석에서는 17.38%의 수분 및 69.03%의 가연분 그리고 6.24%의 회분으로 이루어져 있다. 원소분석결과는 탄소 산소 수소 순으로 이루어져 있다. 생활쓰레기의 저위 발열량은 2973.8kcal/kg 이며 고위 발열량은 5209.94 kcal/kg 결과를 얻었다.

• 자원리싸이클링
• /
• 제10권4호
• /
• pp.34-41
• /
• 2001

현재 전량매립 처분되고 있는 차피파쇄잔류물(shredder residue)의 연료로써의 활용 가능성을 모색하기 위한 분석평가시험을 실시하였다. 수집한 차피파쇄잔류물을 입도별 및 재질별 선별작업을 통해 분류하고 이들 시료에 대한 Cl, S, 회분 및 발열량에 대한 화학분석을 실시하였다. 플라스틱에 함유된 PVC의 영향으로 대상시료 3종류 중 1 종류만을 제외하고는 시료의 평균 Cl 함량은 모두 4wt%를 상회하였다 반면, S 함량은 0.25∼0.39wt%로써 비교적 낮았다. 발열량의 경우 플라스틱이 10,000kcal/kg 이상으로 가장 높았으며, 나무/종이 및 섬유류가 4,000 kcal/kg 정도로써 가장 낮게 나타났다. 차피파쇄잔류물 중의 금속성분은 Fe 가 6∼8.5 wt%인 것을 제외하고는 모두 미량인 것으로 확인되었으며, 유독성 중금속인 Hg와 Cr(VI)은 검출이 되지 않았고, Cd은 0.0004∼0.0009wt%로 극미량이 검출되었다.

• 한국산업융합학회 논문집
• /
• 제25권2_1호
• /
• pp.149-159
• /
• 2022

Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.