• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.652-655
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• 2005

Considering the fact that more than $97\%$ of fossil energy resources such as oil and natural gas needed in Korea rely on import, primary concern of the national economy is to secure future energy sources. Gas hydrates. which is non-conventional types of natural gas, distribute worldwide, especially in marine and permafrost Gas hydrates draw great attention recently as a new clean energy resources substituting conventional oil gas due to its presumed huge amount of volume reaching 10 trillion tons of gas and environmentally friendly characteristics. Results of preliminary survey by Korea Gas Corporation (KOGAS) and Korea Institute of Geoscience and Mineral Resources (KIGAM) showed that gas hydrates can be present in deep sea over 1,000m water depth in the East Sea. Gas hydrates can contribute to the rapidly increasing consumption of natural gas in Korea and achieve the self-support target by 2010 with $30\%$ of total natural gas demand. This study presents the potentialities and development prospects of gas hydrate as a future energy source.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.2
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• pp.218-226
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• 2006

It can be obtained from hydrocarbon and water, specially production of hydrogen from natural gas is most commercial and economical process among the hydrogen production methods, and has been used widely. However, conventional hydrogen production methods are dependent on fossil fuel such as natural gas and coal, and it may be faced with problems such as exhaustion of fossil fuels, production of greenhouse gas and increase of feedstock price. Thermochemical hydrogen production by nuclear energy has potential to efficiently produce large quantities of hydrogen without producing greenhouse gases. However, nuclear hydrogen must be economical comparing with conventional hydrogen production method. Therefore, hydrogen production cost was analyzed and estimated for nuclear hydrogen as well as conventional hydrogen production such as natural gas reforming and coal gasification in various range.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.181-185
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• 2008

The new concept for liquefaction of natural gas has been designed and simulated in this paper. Conventional liquefaction cycles are usually composed with Joule-Thomson valves at lower temperature refrigerant cycle. The new concept of natural gas liquefaction is discussed. The main difference with conventional liquefaction process is the presence of the turbine at low temperature of MR (mixed refrigerant) cycle. The turbine acts as expander but also as an energy generator. This generated energy is provided to the compressor which consumes energy to pressurize refrigerants. The composition of the mixed refrigerant is investigated in this study. Components of the refrigerant are methane, propane and nitrogen. Composition for new process is traced with Aspen HYSYS software. LNG heat exchangers are analyzed for the new process. Heating and cooling curves in heat exchangers were also analyzed.

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

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.16-21
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• 2003

Natural gas is one of the promising alternative fuels because of the abundant deposits and the cleanness of emission gas. It can be used in conventional gasoline engine without major modification. Natural gas has some advantages than gasoline i.e. the high octane number, good mixing condition because of gas and wide inflamable limit. In the present study, a $1.8{\ell}$ conventional gasoline engine is modified for using the CNG as a fuel instead of gasoline. Performance and emission characteristics are compared between gasoline and CNG with 4 cylinder SI Engine which is controlled by programable ECU. Parameters of experimentation are equivalence ratio, spark timing and fuels. We analyzed the combustion characteristics of the engine using the cylinder pressure i.e. ignition delay, combustion duration and cycle variation. As a result, CNG engine shows lower exhaust emissions but brake torque is slightly reduced compared to gasoline engine. Overall combustion duration is longer than that of gasoline because of lower burning speed.

• Economic and Environmental Geology
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• v.47 no.5
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• pp.551-561
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• 2014

Natural gas is the world's fastest-growing fossil fuel, with consumption increasing from 113 trillion cubic feet(Tcf) in 2010 to 185Tcf in 2040. While conventional natural gas streams from the earth relatively easily, unconventional gas finds are more difficult to develop and more costly to produce. Right now, there are six main types of unconventional gas, including deep gas, gas-containing shale, coalbed methane(CBM), geopressurized zones, Arctic and subsea hydrates, and tight gas. Tight gas refers to natural gas reservoirs locked in extraordinarily impermeable, hard rocks(sandstone, siltstone or carbonate sedimentary rocks). In this study, we analyzed total 375 papers(2000-2014) of tight gas by country, institution, international cooperation etc.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.1
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• pp.21-32
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• 2013

Marine transportation industry is undergoing a number of problems. Some of these problems are associated with conventional marine fuel-oils. Many researchers have showed that fuel-oil is considered as the main component that causes both environmental and economic problems, especially with the continuous rising of fuel cost. This paper investigates the capability of using natural gas and hydrogen as alternative fuel instead of diesel oil for marine gas turbine, the effect of the alternative fuel on gas turbine thermodynamic performance and the employed mathematical model. The results showed that since the natural gas is categorized as hydrocarbon fuel, the thermodynamic performance of the gas turbine cycle using the natural gas was found to be close to the diesel case performance. The gas turbine thermal efficiency was found to be 1% less in the case of hydrogen compared to the original case of diesel.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.9-18
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• 1995

The substitution of conventional fuel oil by alternative fuels is of immense interest due to liquid oil shortage and requirements of emission control standard. Among the alternative fuels, natural gas may be the most rational fuel, because of its widespread resource and clean est burning. Meanwhile, engine simulation is of great importance in engine development. Hence a zero-dimensional combustion model was developed for dual-fuel system. Natural gas was injected directly into the cylinder and small amount of distillate was used to provide the ignition kernel for natural gas burning. The intake air and exhaust gas flow was modeled by filling and emptying method. Although the single zone approach has an inherent limitation, the model showed promise as a predictive tool for engine performance. Its simulation was also made to see how the engine performance was influenced by the fuel injection timings and amount of each fuel.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.639-648
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• 2013

Unconventional natural gas resources are now estimated to be as large as conventional resources. Unconventional natural gas has became an increasingly important source of energy in the world since the start of this century. The factors that drive natural gas demand and supply point more and more to a future in which natural gas plays greater role in the global energy mix. The expansion of using natural gas will be expected in Korea. This research aims to analyze environmental impacts of expansion of unconventional natural gas. This research was carried out for comparative analysis between global energy mix and Korea energy mix, and developed a case that reflect the changed energy mix due to the expansion of unconventional natural gas in Korea. Also this research evaluate the production of air pollutants and the cost of the damage in power generation sector. The results of this research can be summarized as that natural gas portion of future global energy mix (about 25%) is greater than Korea energy mix (about 12%). This research developed a case that replace 10% energy of power generation sector to natural gas in the 6th demand supply program, reflecting the changed energy mix due to the expansion of natural gas use. In that case, air pollutants would be reduced gradually through 2015 to 2027. In detail, carbon dioxide reduces 22 million tons and environmental damage cost reduces 4500 billion won by 2027.

• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.20-26
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• 2013

In this study, based on a 12L class diesel engine, a natural gas-diesel dual fuel engine was developed by adding natural gas fuel supply system. For optimal control of dual fuel engine, a conventional diesel engine ECU and a dual fuel ECU were utilized. To convert the dual fuel engine, MPI natural gas injectors were installed on the new modified intake manifold adapter. As a results, the dual fuel engine showed same level of torque, power performance and exhaust gas emissions as those of a diesel base engine.. Furthermore, overall fuel replacement rate was 70~76 % and total fuel cost saving was 37~40%.