• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.269-274
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• 2018

All the $Ni-Co-Ce-ZrO_2$ mixed oxides are prepared by co-precipitations methods. Methanation of CO and $H_2$ reaction is screened tested over different fractions of cerium (2, 4, 7 and 12 wt.%) over $Ni-Co/ZrO_2$ bimetallic catalysts are investigated. The mixed oxides are characterized by XRD, CO-Chemisorption, TGA and screened methanation of CO and $H_2$ at $360^{\circ}C$ for 3000 min on stream at typical ratio $CO:H_2=1:1$. In $Ni-Co/CeZrO_2$ series 2 wt.% Ce loading catalyst shows most promising catalyst for $CH_4$ selectivity than $CO_2$, which directs more stability with less coke formation. The high activity is attributed to the better bimetallic synergy and the well-developed crystalline phases of NiO, $ZrO_2$ and $Ce-ZrO_2$. Other bimetallic mixed oxides NCoZ, $NCoC^{4-12}Z$ has faster deactivation with low methanation activity. Finally, 2 wt.% Ce loading catalyst was found to be optimal coke resistant catalyst.

• Journal of the Korean Society of Industry Convergence
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• v.16 no.1
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• pp.21-26
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• 2013

Burned gas of methane-air mixtures with water vapor have been analysed to study the exhaust emission using gas-chromatography and computation. The computations were carried out for the gas analysis using premix code of Chemkin program to compare the experimental results. The quantity of water vapor contained were changed 5% and 10% of total mixtures, and equivalence ratio of mixtures between 0.6 and 1.2 were tested under the ambient temperature 323K and 373K. The results showed CO, $CO_2$ decreased and $H_2$ increased by increasing the water contents. The CO increased and $CO_2$ decreased by increasing the ambient temperature. The $CO_2$ shows the maximum product at equivalence ratio 1.0, in otherwise the $CH_4$ produced the minimum values in the same range. The results showed little difference between these two methods.

• Animal Bioscience
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• v.36 no.2
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• pp.256-263
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• 2023

Objective: Feed molecular structures can affect its availability to gastrointestinal enzymes which impact its digestibility and absorption. The molecular spectroscopy-attenuated total reflectance Fourier transform infrared vibrational spectroscopy (ATR-FTIR) is an advanced technique that measures the absorbance of chemical functional groups on the infrared region so that we can identify and quantify molecules and functional groups in a feed. The program aimed to reveal the association of intrinsic molecular structure with nutrient supply to animals from canola feedstocks and co-products from bio-oil processing. The objective of this study was to characterize special intrinsic carbohydrate and protein-related molecular structure spectral profiles of feedstock and co-products (meal and pellets) from bio-oil processing from two source origins: Canada (CA) and China (CH). Methods: The samples of feedstock and co-products were obtained from five different companies in each country arranged by the Canola Council of Canada (CCC). The molecular structure spectral features were analyzed using advanced vibrational molecular spectroscopy-ATR-FTIR. The spectral features that accessed included: i) protein-related spectral features (Amide I, Amide II, α-helix, β-sheet, and their spectral intensity ratios), ii) carbohydrate-related spectral features (TC1, TC2, TC3, TC4, CEC, STC1, STC2, STC3, STC4, TC, and their spectral intensity ratios). Results: The results showed that significant differences were observed on all vibrationally spectral features related to total carbohydrates, structural carbohydrates, and cellulosic compounds (p<0.05), except spectral features of TC2 and STC1 (p>0.05) of co-products, where CH meals presented higher peaks of these structures than CA. Similarly, it was for the carbohydrate-related molecular structure of canola seeds where the difference between CA and CH occurred except for STC3 height, CEC and STC areas (p>0.05). The protein-related molecular structures were similar for the canola seeds from both countries. However, CH meals presented higher peaks of amide I, α-helix, and β-sheet heights, α-helix:β-sheet ratio, total amide and amide I areas (p<0.05). Conclusion: The principal component analysis was able to explain over 90% of the variabilities in the carbohydrate and protein structures although it was not able to separate the samples from the two countries, indicating feedstock and coproducts interrelationship between CH and CA.

• Journal of Environmental Science International
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• v.32 no.1
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• pp.47-55
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• 2023

This study evaluated the biochemical methane potential (BMP) of primary sludge, secondary sludge, and food waste in batch anaerobic mono-digestion tests, and investigated the effects of mixture ratio of those organic wastes on methane yield and production rate in batch anaerobic co-digestion tests, that were designed based on a simplex mixture design method. The BMP of primary sludge, secondary sludge and food waste were determined as 234.2, 172.7, and 379.1 mL CH₄/g COD, respectively. The relationships between the mixing ratio of those organic wastes with methane yield and methane production rate were successfully expressed in special cubic models. Both methane yield and methane production rate were estimated as higher when the mixture ratio of food waste was higher. At a mixing ratio of 0.5 and 0.5 for primary sludge and food waste, the methane yield of 297.9 mL CH₄/g COD was expected; this was 19.4% higher than that obtained at a mixing ratio of 0.3333, 0.3333 and 0.3333 for primary sludge, secondary sludge, and food waste (249.5 mL CH₄/g COD). These findings could be useful when designing field-scale anaerobic digersters for mono- and co-digestion of sewage sludges and food waste.

• Resources Recycling
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• v.18 no.4
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• pp.62-69
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• 2009

We researched separation of mixed waste acids with HF, $CH_3COOH$, $HNO_3$ that were produced during a semiconductor wafer process to recycle these acids. At first, we manufactured the fluoride compound in form of $Na_2SiF_6$ by precipitating HF using $NaNO_3$ and Si powder. The concentration of HF was reduced from the initial concentration of 127 g/L to 0.5 g/L with an HF recovery ratio of 99.5%. After the manufacture of $Na_2SiF_6$, the concentration of $HNO_3$ and $CH_3COOH$ demonstrated 502 g/L and 117 g/L respectively. Following these findings we added NaOH in this $CH_3COOH/HNO_3$ mixed acid in order to obtain pH=4. Next we separated the $CH_3COOH$ and recoverd it through the use of vaccum evaporation at -440 mmHg, $95^{\circ}C$. The concentration of the recovered $CH_3COOH$ was approximately 15% and the recovery ratio of $CH_3COOH$ was over 85%. We precipitated the $NaNO_3$ by cooling the concentrated solution to $20^{\circ}C$ with a $HNO_3$ recovery ratio of over 93%. We confirmed that only $Na_2SiF_6$ and $NaNO_3$ were manufactured by XRD analysis after drying these precipitants at $90^{\circ}C$. The precipitants demonstrated a purity of approximately 97% and 98% respectively. Therefore, the purity of the precipitants proved to be similar to that of commercial products.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.553-560
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• 2010

The characteristics of syngas-oxyfuel combustion has been investigated experimentally in the present study. Experimental measurements were conducted to aid a fundamental design of a syngas-oxyfuel combustor with a double coaxial burner configuration. To examine the effects of different syngas fuels on combustion characteristics, various fuel types are utilized such as commercial coal gases (Texaco, Shell), COG (cokes oven gas), and $CH_4$ as a main component of natural gas. $CO_2$ was added to the four fuel types as a diluent gas to reduce the flame temperature. The flame images and emission characteristics of NOx and CO were examined for various equivalence ratio and $CO_2$ dilution ratio. The results show that CO emission was rapidly increased as equivalence ratio approached the stoichiometry condition by reducing the amount of oxygen. As the $CO_2$ dilution increased, CO emission increased while NOx emission decreased due to reduced flame temperature. When the syngas-oxyfuel combustor is operated with 20~40% of $CO_2$ dilution ratio, the CO and NOx emission levels were kept below 50 ppm and 25 ppm, respectively, with a high concentration of $CO_2$ over 95 vol.% in exhaust gases.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.557-562
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• 2007

The purpose of this paper is to investigate the reforming characteristics and maximum operating condition for the hydrogen production by methane reforming using the compression ignition engine induced partial oxidation. An dedicated compression engine used for methane reforming was decided operating range. The partial oxidation reforming was investigated with oxygen enrichment which can improve hydrogen production, compared to general reforming. Parametric screening studies were achieved as $O_2/CH_4$ ratio, total flow rate, and intake temperature. When the variations of $O_2/CH_4$ ratio, total flow rate, and intake temperature were 1.24, 208.4 L/min, and $400^{\circ}C$, respectively, the maximum operating conditions were produced hydrogen and carbon monoxide. Under the condition mentioned above, synthetic gas were $H_2\;22.77{\sim}29.22%,\;CO\;21.11{\sim}23.59%$.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.685-693
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• 1997

We have studied the reforming of carbon dioxide with methane over various supported nickel catalysts. The nickel supported on natural zeolite showed the highest activity and the nickel on acidic support showed higher activity and slow deactivation compared to nickel on basic support. The activity of nickel on natural zeolite increased with increasing loading ratio and showed almost constant activity above 10wt.% loading of nickel. The conversion and yield of products were affected by the mole ratio of reactants and the highest yields of CO and $H_2$ were obtained at $CH_4/CO_2=1$. The deactivation of catalyst was caused by deposition of coke which was formed by the decomposition of methane. The shape of coke was shown to be whisker tripe carbon, and it brought out the slow deactivation of catalyst.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.93-101
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• 2000

The objective of this study was to evaluate the possibility of co-digestion of food waste and sewage sludge mixture using anaerobic system. The Biochemical methane Potentials of cabbage and food waste were $297ml\;CH_4/g$ VS and $306.7ml\;CH_4/g$ VS, respectively. The biodegradability of food waste was 60%. The concentrations of acetate, propionate, and isobutyrate produced during the aerobic acidogenesis of food waste for 36 hours were 7,000~7,200 ppm, 260~280 ppm, 380~400 ppm, and 40~50 ppm, respectively, of which acetate was over 85%. The concentrations of acetate, propionate, and isobutyrate produced during the anaerobic acidogenesis for 36 hours were 1,400~1,600 ppm, 30~40 ppm, 220~250 ppm, and 260~300 ppm, respectively, of which acetate was over 70%. The biodegradabilities of aerobic and anaerobic acidogenesis were 30% and 25%, respectively. Methanogensis could be activated under 1 % of NaCl and 1,000 ppm of volatile fatty acids at the range of pH 6.8~7.2. The maximum mixture ratio of food waste and sewage sludge in the present study was 2:8 by the result of VS removal rate and Methane production.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.323-328
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• 1989

This study was conducted to find out the behavior of anaerobic microorganisms and anaerobic decomposition products of rice straw in the strict anaerobic condition. The number of methanogenic bacteria were more isolated than cellulolytic bacteria from the digester decaying rice straw during the entire incubation time. The activity of anaerobic microorganisms, such as methanogens and cellulolytics, were high the early incubation time in the treatment of rice straw with urea, but without urea was low at that time and increased moderately after 10 days incubation. Volatile fatty acid as intermediate anaerobic decomposition products had a longer retention time and higher accumulation rate in the treatment of rice straw without urea than with urea, and predominant fatty acid was propionic acid. Gas generation rate as final products were very intimate relationship with the activity of methanogenic bacteria. Average Eh value was -250mV during the incubation time and $CH_4$ : $CO_2$ percent ratio was about 60~65 : 35~40 in this Eh value. Decomposition rate of rice straw calculated from $CH_4$ and $CO_2$ gas wars 45.6% for 50 days in the treatment of rice straw with urea, and 36.8% without urea.