• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.85-94
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• 2007

Rice straw, produced as an agricultural by-product, is usable biomass as fuels if depolymerized to monomer unit, because the chemical structure are similar to high octane materials found in gasoline. In this study, parameters of thermochemical degradation by solvolysis reaction of rice straw such as the effect of reaction temperature, reaction time and type of solvent on conversion yield and degradation products were investigated. It was found that the effectiveness of the solvent on the solvolysis reaction was as follows; acetone>cresol>butanol. When acetone was used as a solvent, the highest rice straw conversion was observed to be 91.5% at $500^{\circ}C$, 40 min. Combustion heating value of liquid products from thermochemical conversion processes was in the range of 7,380 cal/g. The energy yield and mass yield in acetone-solvolysis of rice straw was as high as 69.0% and 38.2 g-oil/100g-raw material after 40 min of reaction at $350^{\circ}C$. Various aliphatic and aromatic compounds were detected in the rice straw solvolysis products. The major components of the solvolysis products, that could be used as fuel, were 4-methyl-2-pentanone, 3,5,5-trimethyl-2-cyclopentan-1-one as ketones.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.622-628
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• 2016

본 논문에서는 최근 목질계바이오매스를 원료로 한 수송용(transportation) 바이오연료의 국제적 상용화 기술의 흐름과 산업체 동향에 대하여 조사하였다. IEA, Bioenergy Task 39에서 집계한 수송용 바이오연료 관련 산업체에서 목질계 원료를 사용하는 산업체는 93개 업체였고, 그중에서 Commercial type의 산업체를 기준으로 생화학적 전환기술을 채택한 업체는 전체의 84%로 나타나 생화학적 전환공정이 목질계 바이오연료 분야의 주류 기술인 것으로 밝혀졌다. 생화학적 전환공정을 채택한 Commercial type 산업체의 주요 생산품은 바이오에탄올로서 연간 약 115만 5천 톤, 바이오오일은 약 12만 톤으로 전 세계의 수송용 연료에 혼입목표량을 대체하기에 매우 부족한 상황인 것으로 밝혀져 수송용 바이오연료 시장은 기술과 규모 면에서 기술개발과 상용화 노력이 더욱 요구됨이 시사되었다. 또한 pilot type의 산업체에서 생화학공정 및 열화학공정기술을 활용한 실험적 생산이 다수 진행되고 있어, 향후 목질계 원료에 의한 액체바이오연료 기술이 다양하게 실용화될 가능성이 큰 것으로 시사되었다.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.42-50
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• 2013

Solar thermal reactor was studied for hydrogen production with a two step thermochemical cycle including T-R(Thermal Reduction) step and W-D(Water Decomposition) step. NiFe2O4 and Fe3O4 supported by monoclinic ZrO2 were used as a catalyst device and Ni powder was used for decreasing the T-R step reaction temperature. Maintaining a temperature level of about $1100^{\circ}C$ and $1400^{\circ}C$, for 2-step thermochemical reaction, is important for obtaining maximum performance of hydrogen production. The controller was designed for adjusting high temperature solar thermal energy heating the foam-device coated with nickel- ferrite powder. A Pill temperature control system was designed based on 2-step thermochemical reaction experiment data(measured concentrated solar radiation and the temperature of foam device during experiment). The cycle repeated 5 times, ferrite conversion rate are 4.49~29.97% and hydrogen production rate is 0.19~1.54mmol/g-ferrite. A temperature controller was designed for increasing the number of reaction cycles related with the amount of produced hydrogen.

• 한국수소및신에너지학회논문집
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• 제19권1호
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• pp.56-63
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• 2008

In this study, thermochemical degradation of hemicellulose by Acetone-Solvolysis, the effects of reaction temperature, conversion yield, degradation properties and degradation products were investigated. Experiments were performed in a tube reactor by varying reaction temperature from $200{\circ}C$ to $400{\circ}C$ at 40 min of reaction time. The liquid products from pyrolysis-liquefaction of hemicellulose contained various kinds of ketones. ketones, as 4-methyl-3-penten-2-one, 3-methylene-2-pentanone, 22,6-dimethyl-2, 5-heptadien-4-one, 4-methyl-2-pentanone, 5-methyl-2-hexanone, 3,5,5-trimethyl-2-cyclohexen-1-one, and bezenes. as 1,4-dimethylbenzene, 1-methyl-2-(1-methylethyl)-benzene, 1,4-dimethyl-2-(2-methylpropyl)benzene, 4-secbutyl-ethyl benzene, could be used as high-octane-value fuels and fuel additives. Combustion heating value of liquid products from thermochemical conversion processes of hemicellulose was in the range of $6,680{\sim}7,170cal/g$. After 40min of reaction at $400{\circ}C$ in Acetone-Solvolysis of hemicellulose, the energy yield and mass yield was as high as 72.2% and 41.2g oil/100g raw material, respectively.

• 한국수소및신에너지학회논문집
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• 제13권3호
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• pp.249-258
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• 2002

Thermochemical water-splitting IS(Iodine-Sulfur) process has been investigating for large-scale hydrogen production. For the construction of an efficient process scheme, two kinds of membrane technologies are under investigating to improve the hydrogen producing HI decomposition step. One is a concentration of HI in quasi-azeotropic HIx ($HI-H_2O-I_2$) solution by elecro-electrodialysis. It was confirmed that HI concentrated from the $HI-H_2O-I_2$ solution with a molar ratio of 1:5:1 at $80^{\circ}C$. The other is a membrane reactor to enhance the one-pass conversion of thermal decomposition reaction of gaseous hydrogen iodide (HI). It was found from the simulation study that the conversion of over 0.9 would be attainable using the membrane reactor using the gas permeation properties of the prepared silica hydrogen permselective membrane by chemical vapor deposition (CVD). Design criterion of the membrane reactor was also discussed.

• 한국수소및신에너지학회논문집
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• 제15권4호
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• pp.333-340
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• 2004

In this study, thermochemical degradation by pyrolysis-liquefaction of cellulose, the effects of reaction time, reaction temperature, conversion yield, degradation properties and degradation products were investigated . Experiments were performed in a tube reactor by varying reaction time from 20 to 80 min at $200{\sim}500^\circ{C}$. Combustion heating value of liquid products from thermochemical conversion processes of cellulose was in the range of 6,920~6,960cal/g. After 40min of reaction at $400^\circ{C}$ in pyrolysis-liquefaction of cellulose, the energy yield and mass yield was as high as 54.3% and 34.0g oil/100g raw material, respectively. The liquid products from pyrolysis-liquefaction of cellulose contained various kinds of ketones, phenols and furans. ketones and furans could be used as high-octane-value fuels and fuel additives. However, phenols are not valuable as fuels.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.13-19
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• 2005

The reaction of steam reforming of methane with commercial catalysts was conducted for thermochemical heat storage. The reaction conditions were investigated for temperature range of 700 to $900\;^{\circ}C$ and steam to carbon mole ratios between 3.0 and 5.0. The reactor was made of stainless steel and it's dimension was 12 cm inside diameter and 6cm long. The effects of space velocity and reactants mole ratio and temperature on the methane conversion and CO selectivity were examined. Optimum reaction condition was determined. There was not a significant difference of methane conversion and CO selectivity compared to conventional reactor.

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 추계 총회 및 학술발표회
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• pp.119-123
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• 2005

The thermochemical splitting of water has been proposed as a clean method for hydrogen production. The IS process is one of the thermochemical water splitting processes using iodine and sulfur as reaction agents. HI decomposition procedure to obtain hydrogen is one of the key operations in the process, because equilibrium conversion of HI is low (22% at $450^{\circ}C$). The silica membranes prepared by CVD. method were applied to the decomposition reaction of HI vapor. The permeation characteristics of hydrogen and nitrogen belong to the Knudsen flow pattern.

• 한국수소및신에너지학회논문집
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• 제18권2호
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• pp.109-115
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• 2007

Solar energy conversion to hydrogen was carried out via a two-step thermochemical water splitting using metal oxide redox pair. To simulate the solar radiation, a 7 kW short arc Xe-lamp was used. Partially reduced iron oxide and cerium oxide have the water splitting ability, respectively. So, $Fe_3O_4$ supported on $CeO_2$ was selected as the active material. $Fe_3O_4/CeO_2$(20 wt/80 wt%) was prepared by impregnation method, then the active material was washcoated on the ceramic honeycomb monolith made of mullite and cordierite. Oxygen was released at the reduction step($1673{\sim}1823\;K$) and hydrogen was produced from water at lower temperature($873{\sim}1273\;K$). The result demonstrate the possibility of the 2-step thermochemical water splitting hydrogen production by the active material washcoated monolith. And hydrogen and oxygen was produced separately without any separation process in a monolith installed reactor. But the SEM and EDX analysis results revealed that the support used in this experiment is not suitable due to the thermal instability and coating material migration.

• 한국수소및신에너지학회논문집
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• 제34권3호
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• pp.316-326
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• 2023

Development of carbon-neutral fuel production technologies to solve climate change issues is progressing worldwide. Among them, methane can be produced through the synthesis of hydrogen produced by renewable energy and carbon dioxide captured through a CO₂ methanation reaction, and the fuel produced in this way is called synthetic methane or e-methane. The CO₂ methanation reaction can be conducted via biological or thermochemical methods. In this study, a 30 Nm³/h thermochemical CO₂ methanation process consisting of an isothermal reactor and an adiabatic reactor was used. The CO₂ conversion rate and methane concentration according to the temperature measurement results at the center and outside of the adiabatic reactor were analyzed. The gas flow into the adiabatic reactor was found to reach equilibrium after about 1.10 seconds or more by evaluating the residence time. Furthermore, experimental and analysis results were compared to evaluate performance of the reactor.