메탄 자열개질기의 자립운전연구

임성광(Sungkwang Lim),배중면(Joongmyeon Bae),강인용(Inyong Kang) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

Structural simplicity is one of the advantages of an autothermal reforming(ATR) reactor. ATR reactor needs no heat-supplying devices such as burners and heat exchanger. The heat balance in an ATR reactor is dependent on operation parameters and they should be carefully determined for reactor stability and high efficiency. To study operation conditions of an ATR reactor, a packed-bed ATR reactor with a commercial catalyst was designed and constructed. Operation parameters such as O₂/C, H₂O/C and GHSV (gas hourly space velocity, /h) were varied and the resultant behavior of the reactor was characterized by analyzing product compositions and monitoring temperatures at various points inside the reactor during operations. Effects of operation parameters on the product compositions in the experiment were different from those predicted by thermodynamic calculations. The difference can be attributed to dependence of the temperature on operation parameters in the real reactor which the thermodynamic calculation does not take into account.

귀금속계열 WGS 촉매 연구

임성광(Sungkwang Lim),배중면(Joongmyeon Bae),김선영(Sunyoung Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Water gas shift reactor in fuel processing is an important part that converts carbon monoxide into hydrogen. Fuel processing system for PEMFC usually has two stages of WGS reactors, which are high temperature and low temperature shifter. In this study we prepared noble metal catalysts and compared their performances with that of a commercial iron chromium oxide catalyst. Noble metal catalysts and the commercial catalyst showed quite different temperature dependence of carbon monoxide conversion. The conversion of carbon monoxide at the commercial catalyst was very low at medium temperature(~300℃) and increased rapidly as temperature increased while the conversion at noble metal catalysts was high in the medium temperature range and decreased as temperature increased, which is thermodynamically expected. Their characteristics agreed well with the literature published, and we are accomplishing further study for improvement of the noble metal catalysts.

휴대용 연료전지를 위한 부탄 자열개질에 관한 연구

배규종(Gyujong Bae),강인용(Inyong Kang),임성광(Sungkwang Lim),배중면(Joongmyeon Bae),김주용(Juyong Kim),이찬호(Chanho Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

This study discusses about research efforts of hydrogen generation from hydrocarbon(e.g., diesel, gasoline, natural gas, and LPG), especially, butane reforming by using Autothermal Reforming Reaction (ATR) technology. Several catalysts were selected for butane ATR. Thermodynamic reactor conditions (temperature, O2/C, S/C) are varied and reforming characteristics of 2 catalysts (Pt and Rh on ceramic supports) and 1 commercial catalyst (FCR-HC35) have been examined. To understand reaction behaviors in an ATR reactor comprehensively, temperature profiles of reactor were observed. By mass transfer limitation, fuel conversion decreases when GHSV was increased. Significant temperature variation along the reactor was observed and it was mainly due reaction kinetics difference between exothermic oxidation and endothermic reforming reaction.

효율적 수소생산을 위한 디젤개질기의 시동 및 운전 기법에 관한 연구

강인용(Inyong Kang),배중면(Joongmyeon Bae),임성광(Sungkwang Lim),홍종성(Jongsung Hong),이신구(Shinku Lee),배규종(Gyujong Bae) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

Reformer requires low energy to reach steady state, and minimal start-up time to avoid solid carbon formation during operation. As known, diesel autothermal reforming(ATR) is started by lighting off fuel and air mixture. The mixing ratio is dominating factor which governs startup time and quantity(or degree) of carbon deposition during oxidation reaction. Once reaction temperature is reached, it is controlled by mixing ratio of reactants such as fuel, air and water by the nature of fast reaction control as well as simple system packaging. In this paper, we report the manipulation effect of each reformer operation parameters such as GHSV(gas hourly space velocity), H₂O/C(steam to carbon ratio) and O₂/C(oxygen to carbon ratio). We find the O₂/C ratio seem to be dominant to control ATR reaction. But the ATR reaction was so sensitive that manipulation of O₂/C ratio was lead to severe carbon formation due to large variation of temperature.

천연가스 자열개질기를 위한 작동조건과 개질효율의 상관관계에 대한 수치해석 연구

박준근(Joonguen Park),이신구(Shinku Lee),임성광(Sungkwang Lim),배중면(Joongmyeon Bae) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.8

The objective of this paper is to investigate characteristics of an autothermal reformer at various operating conditions. Numerical method has been used, and simulation model has been developed for the analysis. Pseudo-homogeneous model is incorporated because the reactor is filled with catalysts of a packed-bed type. Dominant chemical reactions are Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Velocity(GHSV). Temperature at the reactor center, fuel conversion, species at the reformer outlet, and reforming efficiency are shown as simulation results. SR reaction rate is improved by increased inlet temperature. Reforming efficiency and fuel conversion reached the maximum at 0.7 of OCR. SR reaction and WGS reaction are activated as SCR increases. When GHSV is increased, reforming efficiency increases but pressure drop from the increased GHSV may decrease the system efficiency.

천연가스로부터 수소를 생산하기 위한 수증기 개질기의 작동조건과 형상에 대한 수치해석 연구

박준근(Joonguen Park),이신구(Shinku Lee),임성광(Sungkwang Lim),배중면(Joongmyeon Bae) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.1

The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir-Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

수성가스전환반응 페로브스카이트구조 촉매 반응속도 연구

전승현(Jun, Seunghyun),배중면(Bae, Joongmyeon),임성광(Lim, Sungkwang),김기현(Kim, Kihyun) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.11

일산화탄소를 수소로 변환하는 수성가스전환반응(WGSR)은 수소 생산, 연료개질 시스템뿐만 아니라 암모니아 제조, 제철소 제련과정등 일선 산업현장에서 널리 활용되고 있다. 상용공정에서의 WGS반응은 두 단계의 반응기(HTS/LTS)에서 각각 Fe/Cr, Cu/Zn기반 촉매를 사용하여 이루어진다. 하지만 이러한 촉매들은 공기중 자연발화성이 있고 사용전 환원과정이 필요하다. 또한 최근에 많은 연구가 진행되고 있는 귀금속 담지 촉매는 기존 촉매의 단점을 극복하고 활성이 높은 장점이 있다. 이에 본 연구에서 제시한 페로브스카이트 촉매는 상용 촉매, 귀금속 담지촉매 시스템과의 비교를 위하여 제작된 촉매를 사용한 반응시스템과 기존 상용촉매를 사용한 반응시스템을 비교하여 개발 촉매의 성능 수준을 검토하였다. 이러한 결과 페로브스카이트 구조 촉매는 상용촉매의 공정상의 단점과 귀금속 담지촉매의 가격적인 측면에서의 단점을 동시에 극복한 촉매로서 성능 및 메탄화반응 억제 측면에서 우수성을 보유하고 있다는 것을 증명하였다. 이러한 페로브스카이트 구조 촉매의 반응특성을 규명하기 위해 문헌조사해본 결과 기존 수성가스전환반응에서 쓰이는 촉매들의 반응매카니즘은 대표적으로 formate와 redox 반응 두가지가 있었다. 페로스브스카이트 구조 촉매는 그 구조와 귀금속 함량, 활성 등 성능측면에서 귀금속 촉매와 상당히 유사한 측면이 있기 때문에 귀금속 담지 촉매의 반응속도식을 기본으로 하여 실험결과와 일치시켜 페로브스카이트구조 촉매에 맞는 반응속도식을 제시하고 이를 통한 반응파라미터 값을 도출하였다.