• Analytical Science and Technology
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• v.15 no.1
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• pp.80-86
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• 2002

The simultaneous analysis of the odorous compounds designated by law in Korea and Japan was examined with the thermal desorber gas chromatography-mass spectrometry using one column. The approximate concentrations of trimethyl amine, acetaldehyde, methyl mercaptan and dimethyl sulfide were estimated. Styrene, dimethyl disulfide, propionaldehyde, n-butyl aldehyde, i-butyl aldehyde, n-valeraldehyde, i-valeraldehyde, ethyl acetate, toluene, xylene, methyl i-butyl ketone and i-butanol were detected at concentrations of the detection limits of their threshold values. As a typical example of simultaneous analysis of the odorous compounds, the volatile organic compounds emitted from compost procedure of food waste were concentrated and analyzed with thermal desorber/GC/MSD, and major malodorous compounds were estimated from the concentrations and threshold values of the detected components. From the result of analysis, 34 compounds were confirmed and among them, trimethyl amine, i-valeraldehyde, methyl mercaptan, methyl allyl sulfide, dimethyl sulfide, acetaldehyde, ethanol, n-butyaldehyde were expected to attribute to the odor in order of strength.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.137-147
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• 1999

Fluidized-bed thermal desorber coupled with a heat pipe was investigated for the remediation of soil contaminated with diesel oils. Thermal gravimetric analysis by Cahn-balance indicated that the desorption of diesel oils from the soil particles was mainly governed by the internal diffusion at low concentration of less than 0.5 wt. % of oils in the soil particles. In fluidized-bed experiments. increase of fluidizing gas velocity reduced the residual oils of the contaminated soils, the increase of soil feed rate decreased efficiency of fluidized-bed desorber. A mathematical model was developed by incorporating Fickian diffusion kinetics into the Kunii-Levenspiel model Simulation results showed reasonable agreement for the performance of fluidized-bed thermal desorber.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.130-130
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• 2003

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.3
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• pp.250-255
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• 2005

The objective of this paper is to develop a new energy transport system for district cooling application by using type 2 absorption cycle. Cold energy from the LNG storage system is utilized as the cooling source of the condenser and the rectifier. The pressures of the system, UAs of the evaporator and the desorber, and the inlet temperatures of the refrigerant to each component are considered as the key parameters. The results show that UA of the evaporator is more dominant parameter on COP than that of the desorber and the optimum system pressure for the demand side is estimated as 525 kPa. For the present system, it is recommended that the refrigerant inlet temperature of the evaporator be lower than $4.3^{\circ}C$ for long-distance transportation. It is concluded that the cold energy from the LNG storage system can be effectively applied to the long-distance transportation system for district cooling application with the type 2 absorption cycle. The optimum operation conditions are also predicted from the parametric analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.369-376
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• 1999

Experiments were carried out to study the heat transfer characteristics of a disrober for 150 RT LiBr-water absorption heat pump. An experimental apparatus was divided into four sections, a combustion chamber area, two bare-tube areas, and finally a finned-tube area to quantify the heat transfer rate of each section by measuring the generation rate of vapor. Dividing plates was installed at the upper inside part of deserter to prohibit the moving of vapor generated at heating tubes of a section to another section near. In the first bare-tube area, the generation rate of vapor was the largest among the four sections. The finned-tube area only contributed to give sensible heat increase of solution to the saturation temperature. The heat transfer area of the finned-tube area was 52.2%, which absorbed only 9.2% of the total heat from the combustion gas. On the contrary, the heat transfer area of the first bare-tube area was 16.6%, but it absorbed 52.4% of the total absorbed heat. The temperature of the solution at upper part at the finned-tube area was lower than that of the lower part, because weak solution came in upper part of the finned-tube area. But, this tendency was changed at the first and second bare-tube area due to the vigorous heat transfer and fluid flow enhanced by vapor generation through heating tubes. The overall heat transfer coefficient and heat flux were the largest at the first bare-tube area among the other sections.

• Analytical Science and Technology
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• v.22 no.6
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• pp.488-497
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• 2009

In this study, analytical methodology for several organic fatty acids (OFA: propionic acid (PA), butyric acid (BA), isovaleric acid (IA), and valeric acid (VA)) designated as new offensive odorants in Korea (as of year 2010) was investigated along with some odorous VOCs (styrene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol). For this purpose, working standards (WS) containing all of these 13 compounds were loaded into adsorption tube filled with Tenax TA, and analyzed by gas chromatography (GC) system thermal desorber interfaced with. The analytical sensitivities of organic fatty acids expressed in terms of detection limit (both in absolute mass (ng) and concentration (ppb)) were lower by 1.5-2 times than other compounds (PA: 0.24 ng (0.16 ppb), BA: 0.19 ng (0.11 ppb), IA: 0.15 ng (0.07 ppb), and VA: 0.28 ng (0.13 ppb)). The precision of BA, IA, and VA, if assessed in terms of relative standard error (RSE), maintained above 5%, while the precison of other compounds were below 5%. The reproducibility of analysis improved with the aid of internal standard calibration (PA: $1.1{\pm}0.4%$, BA: $10{\pm}0.46$, IA; $12{\pm}0.3%$, VA: $4{\pm}0.1%$), respectively. The results of this study showed that organic fatty acid can be analyzed using adsorption tube and thermal desorber in a more reliable way to replace alkali absorption method introduced in the odor prevention law of the Korea Ministry of Environment (KMOE).

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.189-195
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• 2014

Headspace volatile compounds of cold-stored and freeze-dried Krill Eupausia superba were analyzed to investigate their flavor qualities using a system combining a dynamic headspace isolator, an automatic thermal desorber, and a gas chromatograph-mass-selective detector. Levels of oxidation products of polyunsaturated fatty acids such as aldehydes, alcohols, and ketones, which are known to give seafood a nasty smell because of their low flavor threshold values, increased during cold storage of krill. Notably, levels of 2-methylpropanal, 3-methylbutanal, 2-methylbutanal and 2-butanone increased during its storage. They can be considered index compounds of off-odor according to freshness degradation during storage. By contrast, in freeze-dried krill powder, levels of aldehydes, ketones, and aromatic compounds decreased rapidly. Only alcohols, which did not greatly affect the food flavor, were isolated in large amounts. It was confirmed that levels of oxidized compounds of krill increased during cold storage, but decreased in freeze-dried krill.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.431-439
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• 1999

A generator-GAX combined rectification system of an ammonia absorption heat pump was investigated to get the optimum design values. The mass and heat transfer phenomena of the rectification system were analysed. The number of column plates, equilibrium temperature of solution on each plate and flow rates of solution and vapor generated were predicted. The characteristics of mass and heat transfer of the generator-GAX combined rectification system, i.e. concentration difference of leaving solution and vapor on each column plate, were found to be mainly governed by the pressure of generator, reflex ratio and temperature difference of analyser coolant. The number of rectification column plates for each different pressure in generator was obtained. The optimum locations for installing the feeder from solution-cooled absorber and GAX desorber in generator were predicted. The improvement of COP was followed by the increase of the rectifier efficiency and the number of column plate, and the decrease of reflex ratio.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.81-89
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• 2005

As a typical example of simultaneous analysis of the odorous compounds, the volatile organic compounds from inventory sources in Seongseo industrial area were concentrated and analyzed with thermal desorber/GC/MSD, and major malodorous compounds were estimated. Odor intensity and odor concentration was analyzed simultaneously During a period from November in 2002 to December in 2003, this study was conducted to evaluate malodor emission characterization in major treatment facilities. The major components were Dimethyl sulfide, Dimethyl disulfide, Methyl mercaptane, Ammonia, Benzene, Toluene, m,p-xylene, o-xylene, Styrene, 1,2,4­T.M.B and 1,3,5-T.M.B. Among the six major inventory sources, the odor unit concentration of Night-soil disposal facilities was the highest, $669\~2344\;ou/m^{3}.$

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.451-456
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• 2005

The mathematical model for the heat exchangers of absorber and desorber is made in the elementary control volume method and the thermodynamic properties of working fluid. water/ammonia mixture. are calculated by some fundamental subroutines in RefProp 7.0 and flash subroutines made by authors The simulation results show that two-stage cycle has higher COP than single stage if temperature lift is high: the performance of single stage compression cycle can be improved by increase of absorber pressure. but the performance of two-stage compression cycle can not be improved in this way : the compressor discharging temperature of two-stage compression is much lower than that of single stage cycle. which is very important to the safety operation of CA heat pump. Major parameter comparison between the cycles at their optimal configurations is also given.