• Transactions of the Korean hydrogen and new energy society
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• v.22 no.3
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• pp.313-318
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• 2011

This study is about characteristics of generating efficiency and $NO_x$ emissions of a 30 kW gas engine generator in case of using model biogas with hydrogen addition. In this case, both generating efficiency and $NO_x$ emissions are lower than the case of using urban gas (LNG). However, generating efficiency and $NO_x$ emissions are higher than the case of using model biogas only. It means that adding hydrogen which has a high flame propagation velocity has the possibility to improve the generating efficiency, but simultaneously it is also able to increase the $NO_x$ emissions of a gas engine generator.

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.107-113
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• 2015

To date, the demand for Combined Cycle Power Plant (CCPP) has been continuously increased to overcome the problem of air pollution and lack of energy. In particular, the underground CCPP is exposed to substantial fire and explosion risks induced by gas leakage. The present study conducted numerical simulations to examine the fire behavior and gas leakage characteristics for a restricted region including gas turbine and other components used in a typical CCPP system. The commercial code of FLUENT V.14 was used for simulation. From the results, it was found that flammable limit distribution of leakage gas affects fire behavior. Especially, the flame is propagated in an instant in restricted region with LNG gas. In addition, consequence analysis factors such as critical temperature and radiation heat flux are introduced. These results would be useful in making the safety guidelines for the underground CCPP.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.189-193
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• 2006

Experiments were performed to investigate the melting characteristics of pellet fuel made of LDPE and PP for a waste plastic firing boiler. Pellet fuel in a burner goes through conduction, convection and radiation transferred from flame in a furnace, and complex thermo/chemical processes. To figure out effects of ambient temperature and size of pellet on melting time pellets with a diameter from 5 mm to 40 mm were made to contact high temperature flue gas generated by a LNG firing pilot burner. Though melting processes of plastics include complicated heat transfer in a burner, parameters are limited to flue gas temperature and size for the simplicity in this study. From the results, melting times of LDPE and PP with a diameter of 5mm are 63 and 62 secs respectively at 600 $^{\circ}C$ while 677 and 583 sees respectively for a diameter of 40 mm. At $900^{\circ}C$, melting times of LDPE and PP with a diameter of 5mm are 21 and 24 sees respectively while 408 and 337 secs respectively for a diameter of 40 mm. It is found that melting time of LDPE is longer than that of PP, and melting times of both in general increase with diameter of pellets. It is thought melting is dependent mostly on melting temperature of plastic. It is expected melting times obtained from the study might be taken into account in designing a pellet firing burner for a boiler

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.439-444
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• 2011

To determine the test gases for gas appliances of new gas group, the interrelation between gas interchangeability, including thermal efficiency, of 13A gas appliances and present 13A test gases was experimentally investigated. The test results show that the Wobbe indices in the case of incomplete combustion and the flame lifting limit gas for the new gas group are respectively 2% higher than the upper limit and 1% lower than the lower limit of the Wobbe index range. The most suitable composition of R gas is 96 mol% of methane and 4 mol% of propane; LNG could be also used as R gas. Further, analysis results showed that the hydrogen concentration of flash back limit gas could be lowered from 30 vol% to 23 vol%.