• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.165-174
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• 2010

The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.15-24
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• 2010

This study was conducted to investigate the effects of swine manure (SM) application with additional nitrogen (N) fertilizer on productivity of corn and environmental pollution in com cultivation soil. The experiment was conformed in lysimeter which was constructed with 30 cm diameter, and 100 cm height. Swine manures used in this study were the compost of swine manure fermented with sawdust (SMFWS) and soft rice hulls treated with high temperature and high pressure (SRH), and swine slurry (SS). The application rates of the additional N, as urea, with swine manure were 50 and 100 kgN/ha on each plot. This study was arranged in completely randomized design with three replication. DM yields in SM treatments with mineral N were increased significantly compared to those in SM treatment without mineral N (zero-mineral N) (P<0.05) and increased as the rate of mineral N application increased (P<0.05). DM yields in SMFWS and SS treatments with mineral 100 kgN/ha showed trends similar to those of chemical fertilizer (control) but higher than those of 50 kg N/ha. DM yields tended to be higher in SMFWS and SS treatments than in SRH treatment. Total N contents in SMFWS, SRH and SS treatments with mineral N were increased, compared with SM treatment without mineral N. N contents in SM treatments with mineral N were lower than those of chemical fertilizer treatment, but N content of chemical fertilizer treatment showed trends similar to that of SS treatments with mineral 100 kgN/ha. $NO_3$-N concentration in SM treatments with mineral N were increased significantly, compared to those in SM treatment without mineral N and in chemical fertilizer (P<0.05). $NH_4$-N concentrations in SMFWS and SS treatments with mineral 100 kgN/ha showed trends similar to those of chemical fertilizer, but higher than those of 50 kg N/ha. $PO_4$-P concentration in SM treatments with mineral N were increased significantly, compared to those in SM treatment without mineral N (P<0.05). $PO_4$-P concentration in chemical fertilizer treatment showed trends similar to that of SS treatments with mineral 100 kgN/ha. The concentrations of $NO_3$-N $NH_4$-N and $PO_4$-P increased as the rate of mineral N application increased (P<0.05). The concentrations of $NO_3$-N $NH_4$-N and $PO_4$-P were highly elevated in the concentrated rainy season in the early stage among experimental period. The maximum $NO_3$-N $NH_4$-N and $PO_4$-P concentrations in the leaching water were 3.46 mg/L, 1.11 mg/L and 0.14 mg/L, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.4
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• pp.233-238
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• 2006

The experimental work was conducted to determine the growth characteristics, yield and feed value of sorghum-sudangrass hybrid and $NO_{3^-}N$ leaching by application of various types of livestock manure (LM) at National Livestock Research Institute, Suwon, for 3years (2003-3005). The growth characteristics in chemical fertilizer (CF) was better than others in general. The growth characteristic of sorghum-sudangrass hybrid by the various type of LM was good in order of composted swine manure (CSM) > liquid swine manure (LSM) > composted cattle manure (CSM), whereas the growth characteristics by application level of LM was good in order of LM 100%+CF 25%>LM 75%+CF 25%>LM 100%. Dry matter(DM) yield in LSM and CSM increased by 23% and 18% respectively while DM yield in CCM decreased 24% as compared to CF. Moreover total digestible nutrients (TDN) in LSM and CSM increased by 24% and 18% respectively while TDN in CCM decreased 12% as compared to CF. Crude protein and relative feed value in LM decreased compared to those in CF. $NO_{3^-}N$ leaching by application level of LM showed that there was an increase in order of LM 100%+ CF 25%>LM 75%+CF 25%>LM 100%. Also the high concentration of $NO_{3^-}N$ occurred shortly after application of LM.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.163-168
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• 2012

The objective of this study is to quantify the levels of ammonia and hydrogen sulfide inmechanically ventilated slurry-pit swine house according to pig's growth stage and seasonal condition. Mean concentrations of ammonia and hydrogen sulfide in the housing room of gestation/farrowing pigs were 5.60 (${\pm}2.48$) ppm and 178.4 (${\pm}204.8$) ppb in spring, 2.51 (${\pm}3.08$) ppm and 86.6 (${\pm}112.5$) ppb in summer, 4.96 (${\pm}2.84$) ppm and 182.3 (${\pm}242.6$) ppb in autumn, and 6.82 (${\pm}3.42$) ppm and 206.3 (${\pm}356.8$) ppb in winter, respectively. Mean concentrations of ammonia and hydrogen sulfide in the housing room of nursery pigs were 7.18 (${\pm}3.26$) ppm and 486.0 (${\pm}190.2$) ppb in spring, 4.23 (${\pm}2.95$) ppm and 206.4 (${\pm}186.9$) ppb in summer, 7.02 (${\pm}2.65$) ppm and 465.4 (${\pm}156.8$) ppb in autumn, and 9.25 (${\pm}3.68$) ppm and 618.4 (${\pm}298.3$) ppb in winter, respectively. Mean concentrations of ammonia and hydrogen sulfide in the housing room of growing/fattening pigs were 9.26 (${\pm}3.02$) ppm and 604.4 (${\pm}186.8$) ppb in spring, 6.78 (${\pm}3.88$) ppm and 312.5 (${\pm}215.4$) ppb in summer, 9.34 (${\pm}2.14$) ppm and 578.2 (${\pm}248.1$) ppb in autumn, and 14.65 (${\pm}3.15$) ppm and 825.3 (${\pm}316.9$) ppb in winter, respectively. As a result, mean concentrations of ammonia and hydrogen sulfide in terms of pig's growth stage were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room (p<0.05). The swine house showed the highest levels of ammonia and hydrogen sulfide in winter followed by spring, autumn and summer. However, there was no significant difference of ammonia and hydrogen sulfide among seasons (p>0.05).