• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.683-694
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• 1998

The application of hydrocarbon refrigerants in a hermetic reciprocating compressor for refrigerator is investigated. The selected refrigerants are isobutane(R600a), propane(R290), R12, binary mixture of R600a/R290, and OS-21CII. Both theoretical and experimental investigations have been performed for the selected refrigerants. The test results of hydrocarbon refrigerants have been compared to the traditional refrigerant(R12). The results show that hydrocarbon refrigerants(HC-Blend, OS-21C II) are very good alternatives in the refrigeration system for R12.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.11
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• pp.1031-1037
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• 2000

Isothermal vapor-liquid equilibrium(VLE) data have been obtained for the systems of propane(R290)+1,1,1,2-tetrafluoroethane(R134a) and 1,1,1,2-tetrafluoroethane(R134a)+isobutane(R60A) in the temperature range of 253.15 to 323.15K. Experiments were performed in a circulation type apparatus by injecting vapor through liquid pool using a magnetic pump. Both systems form azeotropes in the temperature range of this study. The experimental results were estimated with the Peng-Robinson equation of state. When the temperature-dependent binary interaction parameter was used in the Peng-Robinson equation of state, the absolute average deviation of the measured bubble point pressures from the values correlated by the Peng-Robinson equation was 0.65% and 0.78% for R290+R134a and R134a+600a, respectively. Azeotropic compositions for both systems were presented.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1945-1950
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• 2004

In this paper, The performance of Kim-Chi refrigerator with three evaporator and one compressor was investigated in employing 55% propane and 45% isobutane (R290/R600a) refrigerant mixture as an alternative refrigerant of R134a. The drop in test was performed by varying both refrigerant charge amount and capillary tube length in order to find both the performance and reliability of a small multi-refrigeration system. As a result, Both the power consumption and COP is increased by about 15% and 10%, respectively as compared to the baseline R134a system. In addition, the propane/isobutene refrigerant mixture system took advantage of the minimization of modification and redesigning of system components because of similar thermodynamic properties with R134a such as saturation pressure, temperature, normal boiling point(NBP) characteristics

• Culinary science and hospitality research
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• v.13 no.1 s.32
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• pp.119-128
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• 2007

Volatile flavor compounds of sauces made from shrimps, crabs or lobsters were analyzed by the combination of canister system, gas chromatography(GC) and mass selective detector(MSD). Of 72 total volatile compounds from 4 kinds of sauces, 45 compounds were identified from shrimp sauce(SS). Ten alkanes, 5 ketones, 3 aldehydes were obtained from SS. Especially, 3-methyl-2-butanone, 2-pentanamine, isobutane, 3-methyl-2-butanol, carbon disulfide and dimethyl sulfide were predominant compounds in SS. In crab sauce(CS), there were 18 compounds identified, including 4 alcohols, 4 alkanes, 3 aldehydes, 2 ketones, acid and amine. 2-Methoxy ethanol, trimethyloxirane and 3-buten-1-ol were special volatile compounds in CC. Volatile compounds from lobster head sauce(LHS) or lobster shell sauce(LSS) were 16 or 18 kinds respectively. The major volatile compounds of LHS were formic acid, 1-propanethiol, $\beta$-pinene and allyl sulfide, and those of LSS were acids, pentane, 3-methyl-1-butanol and 2,4-dimethyl-3-pentanone. It was thought that the volatile compounds identified from sauces as well as shrimps, crabs or lobsters might come from wine, onions, bay leaves or celery used as minor ingredients.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.211-219
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• 1997

Liquid or gas phase alkylation of isobutane with 1-butene for i-octane production was carried out over Cs- or $NH_4$-exchanged $H_3PW_{12}O_{40}$. Pretreatment temperature of the catalyst played an important role on the catalytic activity of heteropoly acids in the liquid phase alkylation. Cation-exchanged $H_3PW_{12}O_{40}$ showed a better total yield and i-octane selectivity than the mother acid in the liquid phase alkylation, and $(NH_4)_{2.5}H_{0.5}PW_{12}O_{40}$ was more efficient than $Cs_{2.5}H_{0.5}PW_{12}O_{40}$ in terms of i-octane selectivity. It was found that the acidic property (deactivation of acid sites) of the catalyst was closely related to the catalytic activity of Cs- or $NH_4$-exchanged $H_3PW_{12}O_{40}$ in the gas phase alkylation. $C_5-C_7$ were mainly formed in the early stage of gas phase alkylation due to the strong acidic property of the catalyst, whereas $C_8$ and $+C_9$ were mainly produced as the reaction proceeded due to the deactivation of acid sites. $Cs_{2.5}H_{0.5}PW_{12}O_{40}$ showed the highest total yield in the gas phase alkylation among the catalysts examined.

• Journal of Hydrogen and New Energy
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• v.26 no.3
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• pp.278-286
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• 2015

This paper presents the analytical results of the thermodynamic performance characteristics for a cogeneration system using regenerative organic Rankine cycle (ORC) driven by low-grade heat source. The combined heat and power cogeneration system consists of a regenerative superheated ORC and an additional process heater in a series circuit. Eight working fluids of R134a, R152a, propane, isobutane, butane, R245fa, R123, and isopentane are considered for the analysis. Special attention is paid to the effect of turbine inlet pressure on the system performance such as thermal input, net power and useful heat productions, electrical, thermal, and system efficiencies. The results show a significant effect of the turbine inlet pressure and selection of working fluid on the thermodynamic performance of the system.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.128-132
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• 1963

A study has been made on the applicability of gas-liquid partition chromatography to the qualitative and quantitative analysis of complex mixture of gaseous hydrocarbons. While phthalate columns are widely used for this $purpose^9$, they separates neither saturated hydrocarbons from the unsaturated nor n-butane from isobutene or butene-1, therefore combined columns such as phthalate and dimethylsulfolane have been used for the perfect separation of gaseous hydrocarbons. It is shown by this study, however, that hydrocarbons having $C_1$ through $C_4$ can be separated with a 2-meters tetraethyleneglycol dimethylether column except ethane from ethylene, and trans-from cis-2-butene especially operated at $15^{\circ}C$$ using helium as the carrier gas. The column effluents were in order of methane, (ethane, ethylene), propane, propylene, isobutane, n-butane, isobutylene, butene-1, (trans-& cis-2-butene, isopentane), (butadiene-1, 3, n-pentane). Two kinds of liquified petroleum gases in market are analysed qualitatively and quantitatively. The results indicate that use of this 2-meters TEGDE column permits the separation and identification of all the commonly encountered aliphatic gaseous hydrocarbons.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.699-705
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• 2011

A combined heat and power cogeneration system driven by low-temperature sources is investigated by the first and second laws of thermodynamics. The system consists of Organic Rankine Cycle (ORC) and an additional process heater as a series circuit. Seven working fluids of R152a, propane, isobutane, butane, R11, R123, isopentane and n-pentane are considered in this work. Maximum mass flow rate of a working fluid relative to that of the source fluid is considered to extract maximum power from the source. Results indicate that the second-law efficiency can be significantly increased due to the combined heat and power generation. Furthermore, higher source temperature and lower turbine inlet pressure lead to lower second-law efficiency of ORC system but higher that of combined system. Results also show that the optimum working fluid varies with the source temperature.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.49-56
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• 2011

In this study a novel cogeneration system driven by low-temperature sources at a temperature level below $190^{\circ}C$ is investigated by first and second laws of thermodynamics. The system consists of Organic Rankine Cycle(ORC) and an additional heat generation as a parallel circuit. Seven working fluids of R143a, R22, R134a, R152a, $iC_4H_{10}$(isobutane), $C_4H_{10}$(butane), and R123a are considered in this work. Maximum mass flow rate of a working fluid relative to that of the source fluid and optimum turbine inlet pressure are considered to extract maximum power from the source. Results show that due to a combined heat and power generation, both the efficiencies by first and second laws can be significantly increased in comparison to a power generation, however, the second law efficiency is more resonable in the investigation of cogeneration systems. Results also show that the working fluid for the maximum system efficiency depends on the source temperature.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.140-145
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• 2014

Exploitation of renewable energies is on the increase to mitigate the reliance on fossil fuels and other natural gases with rocketing prices currently due to the depletion of their reserves not to mention their diverse consequences on the environment. Divergently, there are lots of industries "throwing" heat at higher temperatures as by products into the environment. This waste heat can be recovered through organic Rankine systems and converted to electrical energy with a waste heat recovery organic Rankine cycle system (WHR-ORC). This study uses the annual average condenser effluent from Namhae power plant as heat source and surface seawater as cooling source to analyze a waste heat recovery organic Rankine cycle using the Aspen HYSYS simulation software package. Hydrocarbon mixtures are employed as working fluid and varied in a ratio of 9:1. Results indicate that Pentane/Isobutane (90/10) mixture is the favorable working fluid for optimizing the waste heat recovery organic Rankine cycle at the set simulation conditions.