• International Journal of Automotive Technology
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• v.4 no.1
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• pp.1-8
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• 2003

Wastes such as shredder dust of disposed vehicles can be decomposed into low calorific flammable gases by Pyrolysis gasification. A stationary electric Power generation using an internal combustion engine fuelled with the waste-pyrolysis gas is an effective way to ease both waste management and energy saving issues. The waste-pyrolysis gas mainly consists of H$_2$, CO, $CO_2$ and $N_2$. The composition and heating value of the gas generated depend on the conversion process and the property of the initial waste. This research analyzed the characteristics of the combustion and the exhaust emissions in a premixed charge spark ignition engine fuelled with several kinds of model gases, which were selected to simulate the pyrolysis-gases of automobile shredder dusts. The influences of the heating value and composition of the fuel were analyzed parametrically. Furthermore, optical analyses of the combustion flame were made to study the influence of the fuel's inert gas on the flame propagation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.6
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• pp.360-367
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• 2003

Our research objectives are to determine under what conditions microalgal-based $CO_2$capture from flue gases is economically attractive. Specifically, our objective here was to select microalgae that are temperature, pH and flue gas tolerant. Microalgae were grown under five different temperatures, three different pH and five different flue gas mixtures besides 100% $CO_2$(gas concentrations that the cells were exposed to ranged 5.7-100% $CO_2$, 0-3504ppm SO$_2$, 0-328ppm NO, and 0-126ppm NO$_2$). Our results indicate that the microalgal strains tested exhibit a substantial ability to withstand a wide range of temperature (54 strains tested), pH (20 strains tested) and flue gas composition (24 strains tested) likely to be encountered in cultures used for carbon sequestration from smoke stack gases. Our results indicate that microalgal photosynthesis is a limited but viable strategy for $CO_2$capture from flue gases produced by stationary combustion sources.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.128-139
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• 2000

Environmental concerns and shortage of petroleum have promoted considerable interest in the use of alternate fuels in stationary diesel engine. In this study, a heavy-duty, intercooler-turbocharged 6-cylinder stationary diesel engine was converted into stationary gas engine fueled with propane or natural gas for the cogeneration plants. One of the most important factors in the combustion features of a stationary gas engine is the fuel composition and operating parameters in terms of compression ratio, spark advance, and engine loads. Experiments with different fuel gas and load conditions were carried out with combustion pressure analysis and NOx measurement. Combustion analysis based on P-$\theta$ diagrams was also investigated by means of combustion duration and cycle variation. Compression ratio is 10.0 and ignition timing is set by using the gasoline setting as a base line and advanced toward BTDC. The results show that fuel composition and spark advance have dominant effects on combustion and NOx characteristics at operating conditions.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.713-717
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• 1994

Effects of packing materials on the gas compositions in package of fresh peeled garlic (Allium sativum L.) were investigated. The fresh peeled garlics packed in $20,\;40,\;60\;{\mu}m$ LDPE and $30\;{\mu}m$ HDPE pouches were stored at $20^{\circ}C$, 76% RH. The variables including respiration characteristics, gas compositions, general appearance, and film permeabilities to $O_2$, $CO_2$ and $H_2O$ vapor were measured. A model was evaluated for the prediction of $O_2$ and $CO_2$ equilibrium concentrations inside packages and for the optimization of packaging parameters. Experimental and simulated gas composition results were found to be in good agreement. The $30\;{\mu}m$ HDPE pouch with 4% $O_2$ and 7.5%$CO_2$ equilibrium concentrations conferred the best appearance of peeled garlic, giving 6 days of storage life. As a result, MA seemed to have a beneficial effect on appearance of fresh peeled garlic, possibly due to reduced microbial activity.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.79-87
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• 2015

A thermochemical equilibrium model was constructed for predicting composition of synthesis gas in biomass gasification. The model included estimation of equilibrium constants using Gibbs free energy. After constructing the model, the results were compared with the experimental values and predictions from a previous model. Gas compositions were reasonably well agreed with them and showed effects of operational and fuel condition. When the reaction temperature increased, the lower heating values decreased due to the decrease in CH4 concentrations. The methane concentrations were lower than those observed in experimental results. The model was used to predict the gas composition and heating values for the cases of mixed fuel of charcoal and un-dry woodchips. Although downdraft gasifiers require fuels less than 15% of moisture contents, the model results indicated that the mixed fuel with charcoal and woodchips which had over 25% of moisture contents could be used in the downdraft gasifiers. It might be explained by increase in energy density resulting from mixing charcoal. The results imply that the efforts and costs for drying biomass fuels could be reduced by mixing charcoal or fuels with higher calorific values.

• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.25-30
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• 1973

Experiments were carried out to clarify changes of intercellular gas composition, respiration and ethylene evolution by controlled external atmospheric pressure and external gas composition on apples. Jonathan apples, harvested 25, in September and Rolls apples, harvested 25, in October, 1971 and 1972 were used. Results obtained were as follows: 1. Intercellular gas volumes were proportionally changed by the given pressure, and the given pressure remarkably affected internal gas composition and volume of apples. As intercellular gas volumes were reached in their equilibrium within 5 min. after treatment, the internal atmospheric conditions became constant rapidly. 2. The increase of internal $CO_2$ production was co-related with an amount of internal $O_2$ consumption, therefore, the decreasing period of internal $O_2$ consumption was equalled to the period of climacteric rise in respiration. 3. The increasing of $CO_2$ production followed evolution of $C_2$H$_4$ and this phenomenon on SAP part. was subsequent to NAP part 4. In sub-atmospheric storage, CA effect was also obtained by control of low $O_2$ and high $CO_2$ concentration.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.1
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• pp.54-61
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• 2008

Integrated Gasification Combined Cycle (IGCC) power plant converts coal to syngas, which is mainly composed of hydrogen and carbon monoxide, by the gasification process and produces electric power by the gas and steam turbine combined cycle power plant. The purpose of this study is to investigate the influence of using syngas in a gas turbine, originally designed for natural gas fuel, on its performance. A commercial gas turbine is selected and variations of its performance characteristics due to adopting syngas is analyzed by simulating off-design gas turbine operation. Since the heating value of the syngas is lower, compared to natural gas, IGCC plants require much larger fuel flow rate. This increases the gas flow rate to the turbine and the pressure ratio, leading to far larger power output and higher thermal efficiency. Examination of using two different syngases reveals that the gas turbine performance varies much with the fuel composition.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.21-26
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• 2014

Renewable gas fuels such as biogas and landfill gas have carbon-neutral nature which can reduce carbon dioxide. However, it is necessary to make stable combustion when this fuel is used in power generating SI(spark ignition) gas engines due to its low heating value and non-uniformity. In this study, it was shown that addition of hydrogen can increase combustion stability of gas engine which is running with high inert gas composition. Thermal efficiency and emission characteristics of this engine was also investigated. In addition, a new spark plug with a long electrode was tested and compared with a base spark plug as a way to improve engine efficiency and reduce exhaust emissions.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.3
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• pp.143-150
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• 2000

Ferritic plasma nitrocarburising was performed on pure iron using a modified DC plasma unit. This investigation was carried out with various gas compositions which consisted of nitrogen, hydrogen and carbon monoxide gases, and various gas pressures for 3 hours at $570^{\circ}C$. After treatment, the different cooling rates(slow cooling and fast cooling) were used to investigate its effect on the structure of the compound layer. The ${\varepsilon}$ phase occupied the outer part of the compound layer and ${\gamma}^{\prime}$ phase existed between the ${\varepsilon}$ phase and the diffusion zone. The gas composition of the atmosphere influenced the constitution of the compound layer produced, i.e. high nitrogen contents were essential for the production of ${\varepsilon}$ phase compound layer. It was found that with increasing carbon content in the gas mixture the compound layer thickness increased up to 10%. In the gas pressure around 3 mbar, the compound layer characteristics were slightly effected by gas pressure. However, in the low gas pressure and high gas pressure, the compound layer characteristics were significantly changed. The constitution of the compound layer was altered by varying the cooling rate. A large amount of ${\gamma}^{\prime}$ phase was transformed from the ${\varepsilon}$ phase during slow cooling.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.935-940
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• 2000

The objective of this study was to evaluate the nutritive value of selected fruits (pods and seeds) and leaves of acacia tree species namely; Acacia nubica (nubica), Acacia tortilis (tortilis) and Acacia brevispica (brevispica), Acacia reficiens (reficiens) and Acacia senegal (senegal). A wide variability in chemical composition, polyphenolics and gas production was recorded. The crude protein (CP) ranged from 131 to 238 g/kg DM. Neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin (ADL) were higher in senegal and significantly different (p<0.05) from other species. The nitrogen bound to fiber tended to be higher in leaves than the fruits, ranging from 2.6 to 11.3 g/kg NDF and 1.6 to 3.2 g/kg ADF. The leaves of reficiens and senegal had higher concentrations of total extractable phenolics (TEPH), total extractable tannins (TET) and total condensed tannins (TCT), but lower in NDF, ADF and ADL than the fruits of nubica, tortilis and brevispica. Mineral concentrations varied among species; all were relatively poor in phosphorus, moderate in calcium and magnesium, and rich in microelements. A significant (p<0.05) variation in gas production after 12, 24, 48, 72 and 96 h was recorded between species. Nubica had the highest (p<0.05) rate of gas production (0.0925) while the highest potential gas production was recorded in tortilis. A strong negative correlation between TEPH and TET with gas production after 24, 48, 72 and 96 was established (r=-0.72 to -0.82). Crude protein and TCT correlated negatively but also weakly with gas production characteristics. Organic matter digestibility calculated from gas production after 48 h (OMD48) ranged between 465 g/kg DM in reficiens and 611 g/kg DM in tortilis. The results of this study indicate that acacia species have the potential to be used as feed supplements.