• Korean Journal of Organic Agriculture
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• v.29 no.4
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• pp.613-623
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• 2021

This study was conducted to investigate the effect of addition levels of coffee and green tea by products extract including polyphenols through hot water extraction on rumen fermentation. The treatment groups consisted of coffee extract (CO), green tea extract (GR) and mixed extract (MIX), and the addition level was 10 µL, 20 µL and 30 µL of three levels. The experiment consisted of a total of 10 experimental groups including the control group, and a full factorial design was used. The effect of polyphenol addition in coffee and green tea by-products was analyzed through main and interaction effect of statistical analysis. The total polyphenol content of the extracts was 106.15, 79.10 and 185.25 ㎍ GAE/g DM for coffee by-product, green tea by-product and mixture, respectively. Total gas production was significantly lower in the treatment groups than in the control (114.00 mL/gDM) (p<0.05). Methane emission tended to decrease as the polyphenol addition level increased. Moreover, the MIX showed the lowest methane emission when 30 µL was added (p<0.05). Volatile fatty acids showed a significant difference compared to the treatment group as a control (98.06 mM) (p<0.05), but there was no change according to the level of polyphenols. As a result of the main effect and interaction, it is thought that the effect on methane reduction and improvement of rumen fermentation in MIX20 can be expected. In a series of studies, the addition of 20 µL of a blended extract of coffee and green tea by-products is thought to reduce methane to levels that do not inhibit rumen fermentation.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.13-21
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• 2022

Mushroom waste medium refers to the waste biomass generated after mushroom cultivating. And, the burden of treatment on mushroom farmhouse is increasing due to the absence of appropriate treatment method and increase of treatment costs of the mushroom waste medium. In this study, in order to assess the energy value of mushroom waste medium by an anaerobic digestion, methane potential and anaerobic organic matter decomposition characteristics were investigated. The theoretical methane potential(B_th) of mushroom medium(MM) was 0.481 Nm³-CH₄/kg-VS_added, and the B_th of mushroom waste medium(MWM) was 0.451 Nm³-CH₄/kg-VS_added. The biochemical methane potential(B_u-exp) of MWM was increased by 18% from 0.155 for MM to 0.183 Nm³-CH₄/kg-VS_added for MWM. In the reaction kinetics analysis by the Modified Gompertz model, the maximum methane production rate(R_m) was increased from 4.59 for MM to 7.21 mL/day for MWM and the lag growth phase time(λ) was decreased from 2.78 for MM to 1.96 days for MWM. In the reaction kinetics analysis by the parallel first order kinetics model, the easily degradable organic matter(VS_e) content was increased by 5.89% and the persistently degradable organic matter(VS_p) content was 2.03% in MWM, and the non-degradable organic matter(VS_NB) content was decreased by 7.85%. Therefore, it was evaluated that the anaerobic digestion efficiency of MWM was increased. The anaerobic digestion efficiency of MWM was assessed to be more improved than that of MM.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.730-736
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• 2013

This study was conducted to examine the effects of the salt concentration in seafood wastewater on the high-rate anaerobic digestion process. In the general high-rate anaerobic process test, the TCODcr removal efficiency at 6 hr or more HRT was 81.1~0.7%, and the optimal HRT for seafood wastewater process was found to be 6 hr or more. The methane content in the biogas was 70.1~76.8% during the operation, and was hardly affected by the change in the influent load. The results of the anaerobic digestion efficiency according to the salt concentration showed that the removal efficiency of TCODcr was 83.4~89.2% below a $4,000mgCl^-/L$ salt concentration, and mid-70% at a $5,000mgCl^-/L$ salt concentration. Therefore, the salt concentration had to be kept below $4,000mgCl^-/L$ to ensure stable treatment efficiency. Below a $3,000mgCl^-/L$ salt concentration, the methane generation was 0.2999~0.346$m^3CH_4/kgCODrem.$, which was similar to the theoretical methane gas generation in STP condition ($0.35m^3CH_4/gTCODrem.$). The methane content in the biogas was 64.7~73.3% below a $3,000mgCl^-/L$ salt concentration, but decreased with an increase in the salt concentration, to 50.1~56.9% at a $4,000mgCl^-/L$ concentration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.66-73
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• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90% of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.1
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• pp.49-56
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• 2014

This study was conducted to investigate the biodegradation characteristics of swine and cattle using anaerobic batch tests. The results showed that the maximum methane production rate($MPR_{max}$) and acclimation time(AT) of swine were 46.7 mL $CH_4/g$ VS.d and 17.2 d, respectively. The $MPR_{max}$ and AT of cattle were 56.5% and 24.0% lower than those of swine. The characteristics of anaerobic biodegradation varied with livestock species but $MPR_{max}$ and AT increased linearly with the content of lipid. The $MPR_{max}$ and AT of cattle with content of lipid were more sensitive than those of swine.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.45-52
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• 2016

This study is to predict the biogas production and the content analysis of the organic wastes of three islands located in the City of I. Content analysis for a total of six sections, including pH, BOD, COD, three components (Moisture, Ash, Combustibles)was conducted on the specimens of organic wastes from the representative spots of three islands. From the analysis result of organic waste, it is confirmed that more than $1,750,000m^3$ of methane gas per year will be generated through the calculation of the total methane generation for the COD value. Therefore, if the incineration facility for the organic waste in island region is converted into a biogas production facilities which is non-incineration facility, it seems that the organic waste of efficient utilization is available.

• Plant Journal
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• v.18 no.4
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• pp.58-65
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• 2023

In this study, to increase the methane content of biogas supplied from Nanji Water Regeneration Center and to purify impurities, a three-stage membrane purification process was designed and installed to demonstrate operation. The methane concentration of biomethane produced in the 2 Nm3/h purification process was set to three cases: 95%, 96.5%, and 98%, and the membrane area ratio of the membrane was 1:1, 1:2, 1:1:1, The optimum conditions for the membrane area of the separator were derived by changing to five of 1:2:1 and 1:2:2. 3 stage separation membrane process of 30 Nm3/h was installed to reflect the optimum condition of 2 Nm3/h, and biomethane production of 98% or more of methane concentration was demonstrated. As a result of the operation of the 2 Nm³/h refining device, the methane recovery rate at the 98% methane concentration was 95.6% when the membrane area ratio was 1:1 as the result of the two-stage operation of the separator, and the recovery rate of methane at 1:2 was increased to 96.8%. The methane recovery rate of the membrane three-stage operation was highest at 96.8% when the membrane area ratio was operated at 1:2:1. The carbon dioxide removal rate was 16.4 to 96.4% and the 2:2 to 95.7% film area ratio in the two-step process. In the three-step process, the film area ratio was 1:2:1 to 95.4%, and the two-step process showed higher results than the three-step process. In the 30 Nm3/h scale biogas purification demonstration operation, the methane concentration after purification was 98%, the recovery rate of methane was 97.1%, the removal rate of carbon dioxide was 95.7%, and hydrogen sulfide, the cause of corrosion, was not detected, and the membrane area ratio was 1:2:1 demonstration operation, biomethane production with a methane concentration of 98% or higher was possible.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.662-670
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• 2005

With highly oxygenated fuels the smoke emissions decreased sharply and linearly with increases in the fuel oxygen content and entirely disappeared at an oxygen content of $38wt-\%$ even at stoichiometric mixture conditions The NOx also decreased monotonically with increases in oxygen content. and thermal efficiency slightly improved because of a reduction in cooling loss and improvement in the degree of constant volume combustion. The mechanisms of the significant reductions in emissions and improvement in engine performance were analyzed with a bottom view type DI diesel engine. Together with direct flame images, flame images were taken through an optical fetter passing only two wavelengths for use in 2-D two-color analysis. The results showed that luminous flame decreased significantly with increases in oxygen content and was not detected for neat dimethoxy methane(DMM). The decrease in flame luminosity with highly oxygenated fuels corresponds with decreases in soot and cooling losses, including those due to heat radiation. The 2-D two-color flame analysis indicated that the high temperature flame and high KL factor areas apparently decreased with increasing fuel oxygen content. These results correspond strongly with decreases in NOx. smoke. and cooling loss with increases in oxygen content.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.265-269
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• 2015

Chlorella vulgaris (C. vulgaris) is a spherical unicellular green algae and the diameter ranges from 2 to $10{\mu}m$. C. vulgaris possess nutritional excellence because it contains various functional materials including high protein contents, chlorophyll, carotenoid, and chlorella growth factor (CGF). In order to study effects of mutagen, ethyl methane sulphonate (EMS) was used as a chemical mutagen and some mutants could be obtained. We named 2 type mutants as E14 and E24 obtained after treating with EMS. In the cell growth, growth patterns of mutants were similar to those of the wild type. Chlorophyll contents of E14 and E24 increased up to 99 and 52%, respectively compared to those of the wild type. The carotenoid content of E14 increased to 7%, but the value of E24 decreased 5% compared to that of the wild type. For the lipid contents E24 increased to 23%, while E14 decreased 12% when compared to those of the wild type. As a result, there is no difference between the mutants and wild type in the cell growth, but considering that mutants contains more physiological materials than those of the wild type, we can expect the mutants of C. vulgaris could be used as important high added-value materials.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.280-289
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• 2015

Anaerobic digestion is an efficient and renewable energy technology that can produce biogas from a variety of biomasses such as animal manure, food waste and plant residues. In developing countries this technology is widely used for the production of biogas using local biomasses, but there is little information about the value of these biomasses for energy production. This study was therefore carried out with the objective of estimating the biogas production potential of typical Vietnamese biomasses such as animal manure, slaughterhouse waste and plant residues, and developing a model that relates methane ($CH_4$) production to the chemical characteristics of the biomass. The biochemical methane potential (BMP) and biomass characteristics were measured. Results showed that piglet manure produced the highest $CH_4$ yield of 443 normal litter (NL) $CH_4kg^{-1}$ volatile solids (VS) compared to 222 from cows, 177 from sows, 172 from rabbits, 169 from goats and 153 from buffaloes. Methane production from duckweed (Spirodela polyrrhiza) was higher than from lawn grass and water spinach at 340, 220, and 110.6 NL $CH_4kg^{-1}$ VS, respectively. The BMP experiment also demonstrated that the $CH_4$ production was inhibited with chicken manure, slaughterhouse waste, cassava residue and shoe-making waste. Statistical analysis showed that lipid and lignin are the most significant predictors of BMP. The model was developed from knowledge that the BMP was related to biomass content of lipid, lignin and protein from manure and plant residues as a percentage of VS with coefficient of determination (R-square) at 0.95.This model was applied to calculate the $CH_4$ yield for a household with 17 fattening pigs in the highlands and lowlands of northern Vietnam.