• 한국대기환경학회지
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• 제15권3호
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• pp.249-255
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• 1999

We sdudied effect of additives on catalytic activity in thermal catalytic de-NOx process which was composed of thermal reduction, catalytic reduction and catalytic oxidation stage. Pd-Pt/${\gamma}$-$Al_2O_3$ catalysts with the addition of transition metals(Co, Cu, Fe, Ni, W, Zn, Zr) and rare earth metals(Ce, Sr) were prepared by the conventional washcoating method. Those catalysts were characterized by CO pulse chemisorption, ICP, $N_2$ adsorption, SEM and XRD. The effect of catalyst additives on NOx removal for diesel emission was studied in thermal catalytic de-NOx process at reduction temperature(350~50$0^{\circ}C$), space velocity(5,000~20,000 $hr^{-1}$) and the engine load(0~120kW). The concentraton of CO, $CO_2$, NO and $NO_2$ in the exhaust gas increased with the engine load. On the other hand the concentration of $O_2$ decreased. The de-NOx activityof all prepared catalysts increased with respect to high CO and low $O_2$ level in the thermal reduction stage of the process. Insertion of Ce to Pt-Pd/${\gamma}$-$Al_2O_3$ catalyst showed the best activity of all the catalysts under these experimental conditions. De-NOx catalysts are effective to remove CO in addition to NOx in the catalytic reduction stage.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.415-420
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• 2009

Selective Catalytic Reduction(SCR) has been used for the reduction of $NO_x$ in a steam supply boiler. Recently, the reduction of $NO_x$ becomes an important research field because of its negative effect on an environment. Shape optimization of circular poles installed in the chamber, which is located in upstream of a SCR, has been performed using response surface method and three-dimensional Navier-Stokes analysis to enhance gas flow uniformity. Three design parameters, diameter, arranging angle and stretching ratio of circular poles, are considered in the present study. Throughout the shape optimization of a circular pole, gas flow uniformity is successfully increased by decreasing local recirculation flow in a square duct chamber. Recirculation flow observed in the corner of the square duct can be reduced by proper installation of a guide vane or a blunt body. Detailed flow characteristics are also analyzed and discussed.

• Environmental Engineering Research
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• 제10권5호
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• pp.239-246
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• 2005

The effect of Pt addition over $V_2O_5-WO_3/TiO_2$ catalyst supported on PRO-66 was investigated for NO reduction in order to develop the catalytic filter working at low temperature. Catalytic filters, $Pt-V_2O_5-WO_3/TiO_2/PRD$, were prepared by co-impregnation of Pt, V, and W precursors on $TiO_2$-coated ceramic filter named PRD (PRD-66). Titania was coated onto the pore surface of the ceramic filter using a vacuum aided-dip coating method. The Pt-loaded catalytic filter shifted the optimum working temperature from $260-320^{\circ}C$(for the catalytic filter without Pt addition) to $190-240^{\circ}C$, reducing 700 ppm NO to achieve the $N_x$ slip concentration($N_x\;=\;NO+N_2O+NO_2+NH_3$) less than 20 ppm at the face velocity of 2 cm/s. $Pt-V_2O_5-WO_3/TiO_2$ supported on PRD showed the similar catalytic activity for NO reduction with that supported on SiC filter as reported in a previous study, which implies the ceramic filter itself has no considerable interaction for the catalytic activity.

• 한국대기환경학회지
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• 제14권1호
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• pp.25-33
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• 1998

We have studied the reduction of NO by propane over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution by substitution of metal into A or B site of perovskite oxides. In addition, the reaction conditions, such as temperature, $O_2$ concentration, space velocity have been studed. In the $LaCoO_3$ type catalyst, the partial substitution of Ba, Sr into A site enhanced the catalytic activity in the reduction of NO. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3(x=0 \sim 1.9)$ catalyst, the partial substitution of Fe into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. The surface area and catalytic activity of perovskite catalysts prepared by malic acid method showed higher values than those of solid reaction method. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ catalyst, the conversion of NO increased with increasing $O_2$ concentration and contact time. The introduction of water into reactant feed decreased the catalytic activity.

• 자원리싸이클링
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• 제29권6호
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• pp.114-124
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• 2020

시멘트 산업에서 질소산화물 배출은 중요한 문제로 인식되고 있으며 이를 저감하는 기술은 공정변경, 단계적 연소, 저 NOx 버너, SNCR, SCR로 나눌 수 있다. 이중 시멘트 산업에서 가장 많이 사용되고 있는 SNCR 운영만으로는 향후 강화될 배출허용기준을 만족시키기 어려울 것이 예상되며 SCR 등의 추가적인 장비 개선 및 기술 확보가 필요한 상황이다. 이에 따라 최근에는 국외를 중심으로 SNCR 및 SCR 동시 적용 기술, 분진 및 탈질 필터 기술과 NO 산화를 이용한 제거기술 등을 개발하고 있다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.187-191
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• 2002

The exhaust gas from electric power stations, incinerators and industrial boilers contains considerable amount of harmful nitric oxide which causes air pollution. Selective catalytic reduction system with ammonia as a reductant(NH$_{3}$ SCR) have been applied to remove NOx since 1970. it is widely accepted that the NH$_{3}$ SCR process is the best method for the removal of NOx. In this paper the design of SCR reactor based on the NOx displacement is considered and the design program of SCR reactor is developed. The newly developed design program for de-NOx system maybe used in practice.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 춘계학술대회 논문집
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• pp.187-191
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• 2001

In the paper, an approach to the development of the selective catalytic reduction process of NOx is presented. The reduction process can be efficiently controlled using a conventional combination of feed-forward and feed-back control structures. The aim of this paper is to test and verify an approach to the SCR process which is based on an industrial pilot plant of combustion and nitric oxide formation. The systems are based on measurements of a NOx removal ratio and the fuel flow rate, and NH$_3$slip which are usually available as a part of de-NOx control system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.30-34
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• 1997

This paper Describe a modelling method for SCR(selective Catalytic reduction) system in refuse incineration plant. We consider the SCR system as a single input single output system. For modelling the SCR system, an auto regressive exogeneous(ARX) modelling method is used. In this case, we should design the white noise input for modelling and put it on the system as an input (.NH/sap2/.), and taken an outlet NOx as an output. From these two relations, we design the ARX model with 45 second delay time and transform to discrete system with 0.5 sampling time. Using the obtained SCR model, we simulate the SCR system to reduce the outlet NOx content by a conventional PID control method.

• 청정기술
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• 제20권1호
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• pp.28-34
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• 2014

본 연구에서는 나노 크기의 결정 구조를 가진 타이타니아 담체를 용매열합성법(solvothermal method)을 활용하여 합성한 후 팔라듐과 구리를 담지한 촉매를 제조하였다. 제조된 촉매를 수중 질산성 질소 저감 반응에 적용한 결과, 타이타니아 담체의 결정 크기가 반응 활성에 영향을 미치는 것이 확인되었다. 결정 크기가 작은 담체를 활용한 촉매가 더 빠른 속도로 질산성 질소를 저감하였지만, 반응 중 pH가 높게 형성되어 질소 선택도가 매우 낮은 현상을 보였다. 이를 해결하기 위해 pH 완충제인 이산화탄소를 공급하여 질소 선택도를 약 60% 증가시켰다. 상기에 언급한 촉매를 대상으로 질소 흡-탈착, X-ray diffraction (XRD), $H_2$-temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) 등의 다양한 특성화 분석을 수행하여 촉매의 반응활성과 물성간의 상관관계에 대해 조사하였다.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2762-2770
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• 2000

The refuse incineration plant has an important role in saving the combustion energy for local heating system. But harmful combustion gas(NOx etc.) leads to some serious environmental problem. To reduce the gas, a SCR(Selective Catalytic Reduction)system is installed and it is controlled by adjusting the flow of ammonia gas(NH3) . In this paper, we apply a repetitive control method to reduce NOx by adjusting the flow of ammonia gas for SCR system in a refuse incineration plant which is located in Haeundae, Pusan, Firstly, we analyze the inlet NOx period by FFt method, and verify its periodic variations. Secondly, we design a repetitive control system by using state space model method. Lastly, the effectiveness of repetitive control system is shown by comparing to a conventional PID control in simulation and experimental results.