SULEV 규제에 대응하는 HCA 촉매 개발과 TWC와의 혼합효과에 관한 연구

정석진 전남대학교 촉매연구소 2001 觸媒硏究 論文集 Vol.22 No.-

산업용 보일러 배기가스 중의 NO_x 제거를 위한 TiO_2 담지 산화 중석 촉매들의 내열성과 그 촉매표면 산성특성과의 상관관계

丁碩鎭,李重範 慶熙大學校 1989 論文集 Vol.18 No.-

In order to suggest an efficient catalyst systems for the NOx reduction of flue gases from industrial boilers, TiO_2 supported WO_3, WO_3-V_2O_5, V_2O_5 and WS_2 catalysts were tested for the performances of NOx reduction at high reaction temperature range (250-500℃) using a simulated flue gas system. It was found that while the proposed WO_3/TiO_2 and V_2O_5-WO_3/TiO_2 catalysts showed a significant high NOx reduction efficiencies at about 350-400℃, the conventional commercial catalyst of V_2O_5/TiO_2 showed a significant drop in NOx reduction efficiency due to the excessive NH_3 oxidation. From the measurements of surface acidities of those catalysts, it was found that the acidities are well correlated with the activities of NOx reduction. The reason of high activity of WO_3 series catalysts at high reaction temperature seems due to the low value of surface excess oxygen compared with that of V_2O_5/TiO_2 catalyst. The active site for NOx reduction of WO_3/TiO_2 seems equivalent to the acid site of that catalyst.

자동차 배출가스 정화용 Pd담지 γ-Alumina 촉매에 있어서 조촉매 성분의 첨가에 따른 열적 노화효과에 관한 연구

정석진,임상윤 慶熙大學校 材料科學技術硏究所 1989 材料科學技術硏究論集 Vol.2 No.-

For the purpose of suggesting the heat resisting catalyst for automobile emission control, various catalysts, Pd-WO_(3) and Pd-La systems, were characterized before and after thermal aging. It was found that La forms amorphous surface compound on the support by strong metal-support interaction (SMSI). And by temperature programmed desorption (TPD) experiment, it was found that the distribution of acid site on the catalyst was changed from Lewis site which is weak acid site to Bro¨nsted site which is strong acid site by adding the promoters. After thermal aging, it was observed that the acidity of Pd-WO_(3) system was decreased largely because of losing acid site by metal vaporization. On the other hand, there was pretty small change in the property of matter of Pd-La system. Therefore, it could be considered that La forms heat resisting amorphous surface compound on the support by SMSI.

低溫에서의 선택적 酸素化學吸着技法과 NH_3吸着 IR Spectra를 이용한 MoO_3/SiO_2觸媒들의 酸性特性에 관한 硏究

丁碩鎭,李楨熙 慶熙大學校 1987 論文集 Vol.16 No.-

The surface acid properties of the differently loaded sulfied molybdenum-oxide catalysts prepared with a special supprot acid-treatment technique were examined using a LTOC techique(Low temperature Sellective O_2 chemisorption) at -78℃, FT-IR spectra at 170℃, and a amine titration method at 30℃, respectivey. It was found that LTOC technique was applicable for the M_0O₃/SiO_2 catalyst systems with support acid-treatment procedures to give a meaningful surface characteristics of dispersion and acidities. Also it was found that the O_2 chemisorption values and acidities of M_0O_3/SiO_2 cataysts were linearly dependent and therefore. correlated quite well. This means that the variety of surface acidities is due to the change in the composition of From the NH_3 chemisorbed IR spectra, it was found that the acidic sites of M_0O_3/SiO_2 catalysts are consist of Bro¨nsted and Lewis sites before and after support acid pretreatment, respectively, surface compounds which are equvalent to active site for the oxygen chemisorption.

SULEV 규제에 대응하는 HCA 촉매 개발과 TWC와의 혼합효과에 관한 연구

정석진 전남대학교 촉매연구소 2000 촉매학술발표회 Vol.- No.17

대기오염이 증가함에 따라서 여러 선진국가에서는 엄격한 자동차 배기가스의 규제(예:SULEV)를 입법화하여 이를 강력히 시행하고 있다. 이러한 추세에 따라 이에 대응할 수 있는 배기가스 정화용 촉매 및 정화시스템의 개발요구도 국제적으로 긴박하여지고 있다. 본 연구에서는 기존 삼원 자동차촉매 시스템에서 처리가 불가능하거나 비효율적인 초기저온 시동시의 NOx 및 탄화수소 제거효율의 증진에 초점을 맞추고 있다. 현재까지 제안된 다양한 방법중에서 본 연구에서는 탄화수소 흡착촉매(Hydrocarbon Adsorber, HCA) 시스템을 적용하였으며 HCA에 사용되는 제올라이트의 흡착특성을 중점적으로 다루었다. 또한 제올라이트를 흡착제로 이용하여 귀금속 및 Base metal 등을 첨가하여 제작한 탄화수소 흡착촉매를 삼원촉매와 혼합시켜 저온에서의 NOx 및 탄화수소제거의 활성향상을 다루었다. Air pollution due to the emission from automobiles has become a serious environmental problem in a number of countries. As a counter measure for these problems, many industrially developed countries have strengthened the restriction of automobile emissions such as SULEV (Super Ultra Low Emission Vehicle) legislation. Trapping hydrocarbons adsorbed during the cold start in a material such as a zeolite until the three-way catalyst has reached light off temperature is a potential route to very low emission. The research utilizes the hydrocarbon adsorber (HCA) system in order to abate NOx and hydrocarbon which is emitted at a cold-start temperature. Also, physicochemical (such as, acidic and hydrophobic) properties of zeolite were characterized by various adsorptive techniques. And we studied the combination effects of TWC and HCA which was made by zeolites and precious metals.

WO_3/SiO_2, MoO_3/SiO_2 觸媒들의 擔體酸處理 特性에 관한 硏究

沈敬淑,丁碩鎭 慶熙大學校 1986 論文集 Vol.15 No.-

The surface characteristics of the differently loaded WO_3/SiO_2 and MoO_3/SiO_2 catalysts which were prepared with special support acid-treatment procedures were examined using the N_2 adsorption at-195℃ and NH_3 adsorption at 165℃ each. For the N_2 adsorption, conventional gas volumetric adsorption apparatus, and for the NH_3 adsorption differential scanning calorimentry(DSC) were used. The total surface area per unit weight of support was constant for WO_3/SiO_2 catalyst against the extent of metal loading, but decreased for MoO_3/SiO_2 catalyst. It may be suggested that the formation of surface compound of tungsten oxides on the support surface constitutes the monolayer and the interaction between the support and active metal is more sensitive on MoO_3/SiO_2 than on WO_3/SiO_2. In the acid treatment the acidities of 10 wt% WO_3/SiO_2 and 10 wt% MoO_3/SiO_2 were 6.3 and 30.3 respectively, but those of the acid treated catalyst were 6.6-9.7 and 22-23. The optinum conditions of acid treatment in WO_3/SiO_2 catalyst were found that using the maximum concentration of treatment solution in the range 2-8 N-HCl and that using the shortest treatment time in range 3-8 hr, and die lowest treatment temperature in the range 50-90℃.

NH₃TPD에 의한 SAPO-11 및 Pd/SAPO-11의 표면 산특성에 관한연구

정진호,정석진 慶熙大學校 材料科學技術硏究所 1991 材料科學技術硏究論集 Vol.4 No.-

In order to suggest an efficient catalyst system for methanol-to-olefin, variously prepared (Impregnation, Ion exchange) Pd/SAPO-11 catalysts were characterized using techniques of XRD, ICP, NH₃ TPD etc. From XRD results, it was found that Pd particles of impregnated Pd/SAPO-11 catalyst were found to be existed mainly on the outside of SAPO-11 cage as bulk clusters of large crystalline. On the other hand, ion exchanged Pd/SAPO-11 catalysts has some clue Pd that some portion exist within cage by the process of ion exchange, and the remained Pd exist outside of cage. The content of Pd outside of cage increased by the number of repeatation of ion exchange process as bulk clusters. From calculation of the mean particle size of Pd, the dispersion of Pd in ion exchanged catalyst was better than the impregnated one. From the ICP analysis, it was found that Pd was ion exchanged with Al, p, and Al-P except the cation in the lattice, especially Pd was exchanged with Al, P, and Al-P at 1st and 3rd ion exchange, and with cataion in the SAPO-11 at 2nd ion exchanging. By chemisorbed NH₃ TPD, we are found that the acid amount and strength can be controlled by the optimum mumber of ion exchange trials.

메탄올차량 배기가스 제거용 촉매의 저온활성에 관한 연구

洪鍾盛,丁碩鎭 경희대학교 환경연구소 1993 環境硏究 論文集 Vol.4 No.-

As the major methanol fueled vehicle exhaust components, formaldehyde & methanol conversion over the existing commercial 3-way catalyst was examined in a labolatory flow reactor system. The tested catalyst system were modified silver catalysts which contains different Ag loadings on commercial 3-way catalyst, and german commercial catalysts for methanol engine exhaust manufactured by Engelhard co. Ltd. Silver catalysts were prepared by the wet impregnation of silver nitrate solution on commercial 3-way catalyst. These catalysts were characterized with BET and PSD. In general, the formaldehyde(HCHO) conversion of the tested catalysts was similar to that of methanol(CH3OH). At 100,which is equivalent to the cold start condition, 5 wt% Ag cat. showed the most excellent HCHO and CH3OH conversion. The order of activity for conversion of HCHO & CH30H to carbon dioxide and water vapor was as follows; 5 wt% Ag/3-way cat. > 2 wt% Ag/3-way cat.>german cat. l(front)>german cat. 2(rear)>l0 wt% Ag/3-way cat.>3-wat catalyst. However there was no significant activity difference between those tested catalysts in the hot run condition of 400. Therfore, it could be concluded that the Ag-modified 3-way catalyst was the most effective and practical catalyst system which could be capable of removal the HCHO and methanol at the special condition of low temperature such as cold start condition.

자동차 배출가스 정화용 Pd/γ-AI_(2)O_(3) 촉매의 인 피독에 있어서 La_(2)O_(3)의 첨가효과에 대한 연구

정태훈,정석진 慶熙大學校 材料科學技術硏究所 1990 材料科學技術硏究論集 Vol.3 No.-

In order to suggest an efficient catalyst system for automotive emission control, Pd-La_(2)O_(3) catalyst was characterized before and after phosphorus contact. By H_(2) chemisorption experiment, it was found that the particle size of Pd was decreased and dispersion of it was increased by promotion of La_(2)O_(3) After phosphorus poisoning, it was found that amounts of H_(2) chemisorbed were decreased largely up to certain value (ca. 5wt%). However, there was small changes in the amount of H_(2) chemisorbed between 5wt% and 10wt% phosphorus poisoned catalysts. That is to say, phosphorus of high loading doesn't affect the loss of H_(2) chemisorption site by formation of multilayers on the catalyst. By engine exhaust gas test, it was observed that Pd-La_(2)O_(3) catalyst was pretty sensitive against the phosphorus poisoning.

자동차 Thermostat용 Wax의 제조에 관한 연구

이태형,정석진 慶熙大學校 1992 論文集 Vol.21 No.-

The component analysis of wax for detecting temperature in automobile thermostat and manufacture of it with distilllation and solvent extraction were progressed. From the lift test results of prepared samples, it was found that the solent extracted samples were in the proper range of using as a automobile thermostat. And more accurate wax could be manufactured making narrow of molecular weight distribution by high vacuum fraction distillation and acid treatments after solvent extraction from crude oil pitch.