• 한국연소학회:학술대회논문집
• /
• 2013.06a
• /
• pp.109-110
• /
• 2013

This paper describes gas turbine combustion characteristics of synthetic natural gas which contains a small amount hydrogen content. By conducting ambient pressure high temperature combustion test at gas turbine relevant combustor geometry, the combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, nozzle and dump plane, and flame structure from high speed OH chemiluminescence images were investigated when changing hydrogen content from zero to 5%. From the results, qualitative and quantitative relationships are derived between key aspects of combustion performance, notably NOx/CO emission and combustion instability. Natural gas containing hydrogen up to 5% does not show significant difference in view of all combustion characteristics except combustion instability. Only up to 1% hydrogen addition could not change the pressure fluctuation and phase gas between fluctuations of pressure and heat release. From the results, it can be concluded that synthetic national gas which contains 1% of hydrogen can be guaranteed for the stable and reliable operation of natural gas firing gas turbine.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.1
• /
• pp.155-164
• /
• 1996

Dual-fuel engines are being researched with emphasis on the possible types of natural gas supply systems. Hence, a three-dimensional combustion model by using finite volume method was developed to provide a fundamental understanding of the auto-ignition of pilot distillate and subsequent burning of natural gas, when the natural gas as well as the distillate was directly injected into a quiescent diesel engine like combustion bomb tests and the numerical results were investigated for the mixed combustion phenomena. With high-pressure natural gas injection, it was found that the gaseous fuel injection characteristics had to be well harmonised with that of the pilot distillate. For better combustion efficiency, however, further researches are required for the optimisation of injection system in the existence of air motion.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.3 no.6
• /
• pp.112-122
• /
• 1995

As an alternative fuel producing less exhaust emissions, natural gas is of interest for use both in SI and CI engines. The potential of natural gas fuelled dual-fuel engine is considered high enough. However, much effort has to be made so that gaseous fuel is used efficiently with simultaneous minimum use of pilot oil. Hence, a simplified three-dimensional model, using a finite volume method in cylindrical coordinates, has been developed to facilitate an understanding of the dual-fuel combustion phenomena and to predict the complex interactions between the pilot distillate and natural gas. The computer model was calibrated by comparing it with the experimental results obtained from diesel engine like combustion bomb tests. In the pre-mixed natural gas combustion, the fuel burning was highly reliant on the injection condition and subsequent burning nature of the pilot distillate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.12
• /
• pp.1255-1265
• /
• 2001

A numerical study has been conducted to characterize the transient flow in a utility gas turbine burning natural gas. The solution domain encompasses the supply gas pressure regulator to the combustor of the gas turbine that employs multi-nozzle fuel injectors. Some results produced for verification in the present study agree suite well with the experimental ones. It is found that the total gas flow may decrease noticeably during its combustion mode change, which would be the reason of momentary combustion upset, when a reference case of opening ratios of control valves in the system is applied. Several parameters are then varied in order to make the total gas flow stable over that period of time. Results of this study may be useful to understand the unsteady behavior of combustion system burning natural gas.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.6
• /
• pp.32-41
• /
• 1999

Natural gas is an attractive fuel in view of environment benefits due to its flow carbon-to-hydrogen ratio. However, its compositions and properties are varied depending upon production regional groups. Therefore, study on the combustion characteristics of natural gas engines with a variety of compositions has been demanded for the efficient application of gas engines. This study aims to investigate the effects of gas composition on engine combustion characteristics. It was found that , by controlling an engine with fixed fuel nozzle area, power and heat release were subject to Wobbe Index. And at fixed excess air ratios, power and heat release were subject to low heating value of unit mixture . In addition, in case of constant nozzle area, combustion duration was found to be inversely proportional to CP(Combustion Potential), and the condition of fixed excess air ratios showed no change in combustion duration, regardless of CP.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.153-156
• /
• 2008

MILD combustion has been successfully applied to gaseous fuels and few commercial systems are now in operation. Extending MILD combustion applicability to solid fuel of sawdust is the focus of the present work. The MILD combustion furnace at the University of Adelaide in Australia was used in this study. A measurement of $O_2$ and CO emissions have been carried out in parallel with consideration of NOx emission and compared in each modes of conventional natural gas combustion, natural gas MILD combustion, NOx emission in natural gas MILD combustion mode can be reduced to 20% in comparison with conventional combustion. Emission in cases of air carrying sawdust combustion and $CO_2$ carrying sawdust combustion were also compared. Air and $CO_2$ were sued as a carry gas for the sawdust. It was found that MILD conditions are possible for sawdust particles of less than $355{\mu}m$ without additional air pre-heating. It was also found that when using $CO_2$ as the carry gas the flame inside the furnace was not visible anymore and that NOx emission dropped to less than two folds.

• Journal of the Korean Society of Combustion
• /
• v.12 no.1
• /
• pp.38-47
• /
• 2007

The diversification of import districts of natural gas is trying to prepare an increase in the demand and price. The interchangeability of natural gases should be examined prior to supply to gas appliances, although compositional differences among natural gases are not large. The object of this study is to investigate numerically the thermodynamic and transport properties as well as information on combustion of 6 natural gases. Comparing the properties of BOG1 with those of standard gas, the maximum differences of heating value, Wobbe index, air-fuel ratio, and specific heat are 10%, 4%, 10% and 5.54%, respectively. That is, the BOG1 is required careful application. However, all gases except for BOG1 show the similar properties with standard gas. Finally, the combustion information such as flame temperature and burning velocity are examined. These results will provide the useful information related to the interchangeability of various natural gases in practical combustion appliances.

• Journal of the Korean Society of Combustion
• /
• v.13 no.3
• /
• pp.33-40
• /
• 2008

Two- and Three- dimensional numerical simulations are carried out to understand the combustion characteristics of LNG-fueled gas turbine combustor for power generation using imported and domestic natural gases. Reacting flow characteristics of the swirl stabilized natural gas combustor were understood from the numerical results with the flow conditions selected from the gas turbine operation data. The thermal influences of different natural gases were very small and the fuel composition and flow rate were considered to be tuned well. The flow structures of the recirculation and combustion region was understood from the comparison of the two- and three-dimensional results. The complexity of the three-dimensional swirl flows inside the gas turbine combustor with multiple swirlers was understood those resulting from the interactions of the stage and pilot burners.

• Journal of ILASS-Korea
• /
• v.26 no.4
• /
• pp.204-211
• /
• 2021

Lean combustion performance of natural gas and hydrogen was compared in a spark-ignition engine. The lean combustion engine operation with natural gas was limited due to combustion instability at an excess air ratio (EAR) above 1.8. The total hydrocarbon (THC) emissions increased significantly with increasing EAR. The nitrogen oxides (NO_X) emissions were also high due to the limitation of increasing EAR. The lean combustion engine operation with hydrogen showed superior combustion stability as well as low THC and NO_X emissions, even at high EARs. However, boosting technology was required to reach the high EARs.

• Journal of Hydrogen and New Energy
• /
• v.23 no.4
• /
• pp.412-419
• /
• 2012

Increasing demand for natural gas and higher natural gas prices in the recent decades have led many people to pursue unconventional methods of natural gas production. POSCO-Gwangyang synthetic natural gas (SNG) project was launched in 2010. As the market price of natural gas goes up, the increase of its price gets more sensitive due to the high cost of transportation and liquefaction. This project can make the SNG economically viable. In parallel with this project, KEPCO (Korea Electric Power Corporation) joined in launching the SNG Quality Standard Bureau along with KOGAS (Korea Gas Corporation), POSCO and so on. KEPCO Research Institute is in charge of SNG fueled gas turbine combustion test. In this research, several combustion tests were conducted to find out the effect of hydrogen contents in SNG on gas turbine combustion. The hydrogen in synthetic natural gas did not affect on gas turbine combustion characteristics which are turbine inlet temperature including pattern factor and emission performance. However, flame stable region in ${\Phi}$-Air flow rate map was shifted to the lean condition due to autocatalytic effect of hydrogen.