• Proceedings of the KAIS Fall Conference
• /
• 2007.11a
• /
• pp.344-346
• /
• 2007

본 논문은 유동층반응기에서 메탄의 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 환경에 대한 영향을 최소화한 상태에서 메탄의 전환반응을 메탄 분해촉매활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 메탄의 분해는 생성되는 수소를 이용하였다. 유동층의 이동성, $U-U_{mf}$, 마모, 비산유출 유동화가스의 효율밀도에 따른 영향을 연구하였다.

• Clean Technology
• /
• v.27 no.3
• /
• pp.232-239
• /
• 2021

In order to develop a novel system named "thermal medium and gas circulation type pyrolysis system," this study was conducted to obtain basic data for process simulation before performing the pyrolysis experiment. Polypropylene (PP) was chosen as model material in the basic pyrolysis experiment instead of waste plastic and fluidized sand (hereinafter referred to as "sand"), and it was used as a heat transfer material in the "thermal medium and gas circulation type pyrolysis system." Ni was impregnated as an active catalyst on the sand to promote catalytic pyrolysis. The basic physical properties of PP were analyzed using a thermogravimetric analyzer, and pyrolysis was performed at 600 ℃ in an N₂ atmosphere to produce liquid oil. The distribution of the carbon number of the liquid oil generated through the catalytic pyrolysis reaction was analyzed using GC/MS. We investigated the effects of varying the pyrolysis space velocity and catalyst amount on the yield of liquid oil and the carbon number distribution of the liquid oil. Using Ni/sand, the yield of liquid oil was increased except with the pyrolysis condition of 10 wt% Ni/sand at a space velocity of 30,000 h^-1, and the composition of C₆ ~ C₁₂ hydrocarbons increased. With increases in the space velocity, higher yields of liquid oil were obtained, but the composition of C₆ ~ C₁₂ hydrocarbons was reduced. With 1 wt% Ni/sand, the oil yield obtained was greater than that obtained with 10 wt% Ni/sand. In summary, when 1 wt% Ni/sand was used at a space velocity of 10,000 h^-1, the oil yield was 60.99 wt% and the composition of C₆ ~ C₁₂ hydrocarbons was highest at 42.06 area%.

• Applied Chemistry for Engineering
• /
• v.26 no.2
• /
• pp.154-158
• /
• 2015

In this study, the catalytic activity of ${\gamma}-Al_2O_3$ was investigated for the decomposition of $NF_3$. Reactions for $NF_3$ decomposition were carried out in the range of reaction temperature of $330{\sim}730^{\circ}C$ and GHSV of $3,000{\sim}15,000mL/g-cat{\cdot}h$ in a fixed-bed catalytic reactor system. Thermal decomposition of $NF_3$ was also performed in order to compare with the catalytic decomposition of $NF_3$. The conversion of $NF_3$ by the catalytic decomposition at $400^{\circ}C$ was four times higher than that of the thermal decomposition. It was confirmed that the reaction behavior of $NF_3$ over ${\gamma}-Al_2O_3$ exhibited two reaction pathways in the presence of steam. Fluorine in $NF_3$ over ${\gamma}-Al_2O_3$ was chemically absorbed to $AlF_3$ by the gas-solid reaction in the absence of steam. The catalytic decomposition of $NF_3$ occurred by hydrolysis with steam. It was also confirmed by FT-IR analysis that $NF_3$ was completely decomposed to NOx and HF above $500^{\circ}C$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.117-119
• /
• 2017

The multi-stage catalytic igniter for hybrid rocket auto ignition is described in this paper. After charging the catalyst and pre-heating the first stage, the $N_2O$ was supplied at the first stage with the low mass flow rate, and then the $N_2O$ with the high flow rate was supplied into the second stage. Even though the $N_2O$ flow rate was high, it was decomposed by supplying the high temperature gas which was evolved from the $N_2O$ decomposition in the first stage. This multi-stage ignitor resulted in the decrease of the ignition time in comparison with the previous ignitor, and confirmed the possibility of $N_2O$ decomposition with the high flow rate using the multi-stage catalytic-ignition system.

• Clean Technology
• /
• v.26 no.3
• /
• pp.196-203
• /
• 2020

In this study, a Cu/hexaaluminate catalyst was prepared by a co-precipitation method, and then a binder was added to form a pellet. A catalyst in which Ni and Ru promoters were added to a Cu/hexaaluminate pellet catalyst was prepared. This study focused on examining the effect of the addition of Ni and Ru promoters on the properties of Cu/hexaaluminate catalysts and the decomposition reaction of ADN-based liquid monopropellants. Cu/hexaaluminate catalysts had few micropores and well-developed mesopores. When Ru was added as a promoter to the Cu/hexaaluminate pellet catalyst, the pore volume and pore size increased significantly. In the thermal decomposition reaction of ADN-based liquid monopropellant, the decomposition onset temperature was 170.2 ℃. Meanwhile, the decomposition onset temperature was significantly reduced to 93.5 ℃ when the Cu/hexaaluminate pellet catalyst was employed. When 1% or 3% of Ru were added as a promoter, the decomposition onset temperatures of ADN-based liquid monopropellant were lowered to 91.0 ℃ and 83.3 ℃, respectively. This means that the Ru promoter is effective in lowering the decomposition onset temperature of the ADN-based liquid monopropellant because the Ru metal has excellent activity in the decomposition reaction of ADN-based liquid monopropellant, simultaneously contributing to the increase of the pore volume and pore size. After the thermal treatment at 1,200 ℃ and decomposition of ADN-based liquid monopropellant were repeatedly performed, it was confirmed that the addition of Ru could enhance the heat resistance of the Cu/hexaaluminate pellet catalyst.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2000.04a
• /
• pp.19-144
• /
• 2000

막대한 에너지원을 갖고 있는 고분자 폐기물은 열분해에 의하여 오일화가 가능하며 이 오일은 대체 연료유로서 사용이 가능하다. 그러나 이 연료유를 생산하기 위해서는 폐플라스틱 및 폐타이어의 경우는 공정을 서로 달리하여야 이용이 가능하며 생성유의 유질에서도 다소 차이가 있다. 올레핀계가 함유된 폐플라스틱을 열분해 오일화 하기 위해서는 분해 촉매를 사용하여야 하며 열분해유는 경유분과 d사한 성상을 갖고 있으며 폐타이어의 열분해유는 유황성분 및 BTX 분을 상당량 함유하고 있어서 경유분과는 다소 다른 성상을 갖고 있다. 또한 폐타이어 및 폐플라스틱의 열분해 기술이 사용화되기 위해서는 열분해시 발생하는 Coking 문제 극복 및 시스템에 대한 설계기술이 뒷받침되어야 한다.

• Applied Chemistry for Engineering
• /
• v.27 no.4
• /
• pp.407-414
• /
• 2016

Ex-situ catalytic pyrolysis of a Korean native oak tree over microporous zeolites (HZSM-5, HBeta, and HY) was performed by using a fixed bed reactor. The effect of sample to catalyst ratio and reaction temperature was also investigated to optimize production conditions of high quality bio-oil. Among three catalysts, HZSM-5 showed the highest aromatic formation due to its proper pore size and strong acidity. Although HY and HBeta also showed the catalytic activity, they produced larger amounts of coke due to their larger pore size. The smaller ratio of the sample to the catalyst and higher reaction temperature were also required to maximize the yields of aromatic hydrocarbons via the catalytic pyrolysis of oak tree over HZSM-5.

• Journal of the Korean Wood Science and Technology
• /
• v.14 no.2
• /
• pp.21-28
• /
• 1986

A quartz type gasification reactor was designed and used for pyrolysis and gasification of sawdust, ricestraw and ricehusk. The initial reaction temperature was 350$^{\circ}C$, and up to 550$^{\circ}C$ to complete pyrolysis and gasification reaction. In order to examine the effect of catalyst on reaction temperature, $K_2CO_3$ and $Na_2CO_3$ as catalyst were also used. The product gas mixtures are identified to be CO, $CO_2$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometer. The highest gas volume of the gasified sawdust at 550$^{\circ}C$ amounts to 1800ml/g of sawdust, even though the yield and composition of this product gas are depending on the reaction temperature of the reactor and catalyst used.

• Applied Chemistry for Engineering
• /
• v.16 no.4
• /
• pp.496-501
• /
• 2005

The thermal degradation of ABS in the presence of iron-based metal catalysts has been studied by thermogravimetric analysis (TGA). The reaction of iron-based metal catalysts (ferric nitrate nonahydrate, ammonium ferric sulfate dodecahydrate, iron sulfate hydrate, ammonium ferric oxalate, iron(II) acetate, iron(II) acetylacetonate and ferric chloride) with ABS has been found to occur during the thermal degradation of ABS. In a nitrogen atmosphere, char formation was observed, and at $600^{\circ}C$ approximately 3~23 wt% of the reaction product was non-volatile char. The resulting enhancement of char formation in a nitrogen atmosphere has been primarily due to the catalytic crosslinking effect of iron-based metal catalysts. On the other hand, char formation of ABS in air at high temperature by iron-based metal catalyst was unsuccessful due to the oxidative degradation of the char.

• Proceedings of the KAIS Fall Conference
• /
• 2008.05a
• /
• pp.319-322
• /
• 2008

본 논문은 미분 반응기 및 유동층반응기에서 메탄의 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 일반적으로 고온 분해시 사용되는 니켈과 철 성분을 대신할 철광석을 이용하여 분해특성을 고찰하였다. 환경에 대한 영향을 최소화한 상태에서 메탄의 전환반응을 메탄 분해촉매 활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 또한 고정층에서 공간속도, 입자크기, 비표면적이 미치는 영향을 고찰하여 철광석의 사용가능성을 타진하였다.