• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.339-342
• /
• 2014

Rotary kiln produces lime from limestone through thermal decomposition. Ring formation in kiln internal wall is known issue that decreases productivity. The cause of ring formation is temperature imbalance as flame leans toward upper wall. Therefore, burner nozzle geometry was changed to improve air-fuel mixing state which leads to prevention of ring formation. CFD simulation and experimental test were performed in this study to investigate the effect of air-fuel mixing on flame structure, temperature and $NO_X$ concentration. It is shown that combustion efficiency has been enhanced and $NO_X$ concentration has been decreased by using swirl flow for secondary combustion air. It's also shown that flame has been straightened by using straight flow for secondary combustion air.

• 대한기계학회논문집
• /
• 제15권6호
• /
• pp.2100-2108
• /
• 1991

본 연구에서는 최근 한국동력자원연구소에서 개발한 로타리 킬른형의 도시 쓰 레기 소각로에 대하여 전열해석한 것으로 이 해석을 통하여 소각로에서의 쓰레기, 배 기가스 그리고 로벽에서의 온도 분포를 예측할 수 있다.

• 한국연소학회지
• /
• 제12권3호
• /
• pp.24-32
• /
• 2007

A theoretical model was developed for rotary kiln and computational study was conducted to find the effect of feeding characteristics. One dimensional model with the variations of heating distribution, length of heating zone, excess air ratio and revolution was considered. The comparison of parallel-flow rotary kiln with that of counter-flow was conducted. For parallel-flow type, it is found that the variation of temperature of solid is not great for the zone that is following flame-heating zone. This zone is good to take the special treatment because thermal deviation is small and contacting time is enough for another treatment. Increase of excess air ratio have the effect of decreasing solid temperature. But this effect of decreasing solid temperature goes small for the great excess air ratio. The heating is efficient for the flame which has the maximum heating at the central region of the full length.

• 한국연소학회지
• /
• 제20권2호
• /
• pp.1-13
• /
• 2015

Drying, which is the oldest and most energy-intensive process, is an essential process for treatment of solid product. The specific procedure to design and evaluate the dryers, which are a rotary kiln dryer and a flash dryer, in case of drying the high-moisture coal was described. From determination of size to the heat and mass balance in one-dimensional model were conducted to evaluate the performance of dryers. Heat consumption, inlet gas temperature and size of the dryers were compared between a rotary kiln dryer and a flash dryer. Further considerations to evaluate the reactor elaborately were also discussed. Performance simulation of dryers along with the design procedure described here will provide helpful basis for understanding the concept of reactor design.

• 한국연소학회지
• /
• 제20권2호
• /
• pp.14-27
• /
• 2015

Calcination, which represents thermal decomposition of $CaCO_3$, is the key reaction in a cement process. Some reactions including heating-up also take place simultaneously in the calcination reactors. Basic thermal performance and dimensions of the reactors in two cases, which are a rotary kiln wih a four-stage cyclone pre-heater and a simple single rotary kiln, were compared. To employ the heat transfer, mass transfer and reaction rate as well as calcination, one-dimensional modeling was conducted in each case. Some simplification about the reactors was described, however, the reliable Nusselt number and heat transfer coefficients on the reactors were used to make results reliable.

• Journal of the Korean Wood Science and Technology
• /
• 제22권1호
• /
• pp.12-19
• /
• 1994

An electrically heated experimental lumber dry kiln was retrofitted with a computer-based control system to control kiln conditions more precisely and monitor and record several kiln variables. Flat-sawn 2.5cm-thick Pinus densiflora boards were dried in constant temperature process(65$^{\circ}C$ & 50~60 %RH) and continuously rising temperature process, respectively. The average drying rate in continuously rising temperature process was 5.7 %/hr, which was above 3 times faster than that in constant temperature process. But, the average rate of case-hardening and moisture difference between shells and cores of boards dried in continuously rising temperature process were 82 % and 5.5 %, respectively, which were much larger than those of boards dried in constant temperature process.

• Advances in concrete construction
• /
• 제5권2호
• /
• pp.101-115
• /
• 2017

Cement kiln dust (CKD) is one of the most important waste materials in the cement industry. The large amount of this material, has encouraged researchers to propose new ways to recycle and reuse it. In this paper, effects of adding cement kiln dust to the ordinary Portland cement, on the physical and mechanical properties of ordinary and lightweight concrete were investigated. Results showed that concrete containing CKD, presents lower workability and modulus of elasticity; however, improvements in strength was observed by adding particular amounts of CKD. Eventually, it was found that adding 10% of cement weight CKD is the appropriate percentage for utilizing in manufacturing ordinary and lightweight concrete.

• 한국가구학회지
• /
• 제11권1호
• /
• pp.69-74
• /
• 2000

Pinus $rigida{\times}taeda$ and Liriodendron tulipifira have been planted in this country for about 20 years. They are known as a relatively 13st-grown and useful species. The physical properties such as green moisture contents, specific gravities and dimensional shrinkages were examined with natively grown timbers. The kiln-dry schedules were developed with 30m thick boards by using an oven-fast-drying method. In both species the green MC's of sapwoods were higher than those of heartwoods, but their discrepancies were small. The green specific gravities of Pinus $rigida{\times}taeda$ and Liriodendron tulipifera were 0.48 and 0.41~O.42, respectively. The developed kiln-dry schedules were proven to minimize drying defects for the hoards of 30mm thickness and various width.

• 한국세라믹학회지
• /
• 제24권2호
• /
• pp.161-169
• /
• 1987

An experimental study of the characteristics and the behavior of flames, and the aerodynamic flow pattern was carried out in the present work on a down draft kiln for gas firing. The aim of this work is to establish a behavior of flames and to know the extent to which the flow pattern is affected by the height of baffle plate. The measurements of temperature, concentrations of fuelgas, and kiln pressure were conducted at different temperature in kiln, and at different height of baffle plate. From the obtained results, it was found that the characteristics of thestagnation zone are greatly affected when changing over the height of baffle plate, and the best condition of that was 115m/m.

• 한국가구학회지
• /
• 제14권2호
• /
• pp.13-20
• /
• 2003

This research is to develop kiln-drying schedules for 2.7 mm thick boards of Neolitsea sericea and Dendropanax morbifera, which grow in the southern region of Korean Peninsula. These two species are lesser-known to woodcraft industry in this country. The proper USDA drying schedules for Neolitsea sericea and Dendropanax morbifera were found to be T10-C6 and T10-E6, respectively, by using the Quick Oven-drying Method. The boards dried in a kiln with the newly-developed schedules were revealed to be free from warping and checking.