DEVELOPMENT OF CATALYTIC CONVERTER FOR EMISSION CONTROL OF STATIONARY DIESEL ENGINE Patil Ajinkya Bhaskarrao1, Shinde Rajaram M.2 1M.Tech. Student, 2Assistant Professor, Automobile Engg., Rajarambapu Institute of Technology, Rajaramnagar, Islampur Email: [email protected] Abstract: A catalytic converter is device used driven vehicles while diesel particulate filter to reduce the toxicity of emissions from an and oxidation catalysts converter or diesel internal combustion engine. Also, catalytic oxidation catalyst have so far been the most converters are most commonly used in motor potential option to control particulates vehicle exhaust systems. The function of the emissions from diesel driven vehicle. catalytic convertor is to convert CO, HC and There are different catalytic converter NOx emissions into CO2, water, N2 and O2. In systems used. They are as follows. the present work, design specifications of A. Oxidation Catalytic Converters: catalytic converter for stationary diesel This system ideally converts the oxidising engine have been presented. According to components into O and . The catalyst this design, catalytic converter is developed operates at excess air settings. The air required and then, installed on the single cylinder for the oxidation process is supplied by lean stationary diesel engine. At the successful mixture settings or by secondary air injection. completion of present work it is expected that Oxidation catalysts were used for the first time newly designed and developed catalytic in 1975 on U.S. vehicles. They are no longer converter system will work efficiently to used on passenger vehicles today since three- reduce emissions significantly. way catalytic converters are far more efficient Keywords: Catalytic Converter, emissions. and will additionally convert NOx emissions. Oxidation catalysts are used to an increasing 1. Introduction: degree on diesel engines, however, since they Catalytic converters have been widely used are capable of oxidising soluble particulate on vehicles and have already been proved for matter in addition to the above components.[2] many years to be the most effective technical B. Dual-bed Catalytic Converters: solution to reduce exhaust emissions from This system includes two catalyst systems gasoline engines. The pollutants have negative mounted in line in the exhaust system. A effect on air quality, environment and human reduction catalyst is fitted to minimize NOx health that leads in stringent norms of pollutant emissions, and an oxidation catalyst is used to emission. Numbers of alternative technologies reduce HC and CO emissions. The engine must like improvement in engine design, fuel be operated at air deficiency (Je< 1). This pretreatment, use of alternative fuels, fuel system has therefore certain drawbacks in terms additives, exhaust treatment or better tuning of of fuel consumption and CO2 emissions. the combustion process etc. are being Complex mixture formation control systems are considered to reduce the emission levels of the not required. Since the engine is operated in the engine. Out of various technologies available rich Je range, increased ammonia emissions for automobile exhaust emission control a may result. The nitrogen oxide conversion catalytic converter is found to best option to efficiency is far lower than with three-way control CO, HC and NOx emissions from petrol catalytic converters.[2] ISSN(PRINT):2394-6202,(ONLINE):2394-6210,VOLUME-1,ISSUE-4,2015 87 INTERNATIONAL JOURNAL OF ADVANCES IN PRODUCTION AND MECHANICAL ENGINEERING (IJAPME) C. Three-way Catalytic Converters: table. Depending on the volume of catalytic A characteristic feature of this system is converter, 1200/2 cell density diemensions are that is reduces NOx, and HC and CO by the selected for substrate. same high degree throughout. To achieve optimum emission control results, however, a Table 2. Dimensions of Substrate [1] complex control system (lambda control) is Paramete Cell required. Uncontrolled systems with three-way r Densit catalytic converters of the type that was also y marketed in Germany only reach conversion 400/6. 600/ 900/2. 1200/ efficiencies of approx. 40 to 50%, whereas 5 4 5 2 computer-controlled systems in new condition Substrate 0.86 0.67 0.67 0.31 will reach conversion efficiencies of more than volume, l 95%. Three-way closed-loop catalytic GSA, 2.74 3.48 4.37 4.98 converters currently are the most efficient / l emission control systems available for internal- OFA, % 75.7 81.4 85.6 83.4 combustion engines.[2] , 3074 3990 5412 7589 D. Denox or Lean-burn Catalytic litres/ Converters: Lean-burn or Denox catalytic converters Substrate 339 202 156 83 allow not only CO and HC, but also NOx to be mass, g converted in the excess-air range. They are These diemensions of substrate 1200/2 cell currently in the development stage. NOx density are selected because these dimensions conversion efficiencies in excess of 50% have gives less emissions as compared to other already been demonstrated.[2] substrate. The emission results are shown in following table. 2. Design Specifications of Catalytic Table 3. Emission Reduction [1] Converter: Cell Relative HC Relative In this section, specifications of Geometry Emissions Emissions components of catalytic converter system have been presented. This catalytic converter system 400/6.5 100 100 is designed for Kirloskar stationary diesel 400/4.5 88 94 engine. The detailed engine specifications are 600/4.3 65-74 74-93 described in experimentation section. From the 900/2.5 52-66 59-75 engine specifications, catalytic converter 1200/2 41-57 57 system is designed. For this design, different parameters like space velocity, volume, shape 3. Material of Catalytic Converter: have been considered. The specifications of In this section, material used for designed catalytic converter are shown in components of catalytic converter have been following table. dicussed. The main components of catalytic converter are – Step 1: Outer Dimensions of Catalytic 1. Substrate Converter 2. Catalyst Table 1. Dimensions of Catalytic Converter 3. Washcoat Catalytic Converter 0.44178 L A. Substrate: Volume The substrate have two functions, first is, it Diameter of Catalytic 75 mm supports the catalyst and second is, takes the Converter Body catalyst into maximum contact with exhaust Length of Catalytic 100 mm gases. Converter Body Requirements of Substrate: [1,2] Substrate must be covered with the Step 2: Dimensions of Substrate washcoat The dimensions of substrate are selected Low thermal inertia and efficient heat from volume of catalytic converter. The transfer standard dimensions are shown in following More surface area per unit volume ISSN(PRINT):2394-6202,(ONLINE):2394-6210,VOLUME-1,ISSUE-4,2015 88 INTERNATIONAL JOURNAL OF ADVANCES IN PRODUCTION AND MECHANICAL ENGINEERING (IJAPME) Ability to withstand high operating A. Substrate: temperature An oxidation catalytic converter is a Long durability catalyst coated honeycomb-like, channeled High resistance to thermal shocks metallic substrate, through which exhaust gas From this requirements, metallic substrate is passes. The ceramic substrate is constructed by used in this catalytic converter system and extruding or compressing a ceramic material material used as steel because of following into a honeycomb structure of desired length reasons. and width. Treating the honeycomb substrate Higher mechanical strength with catalyst materials is achieved by drenching High thermal conductivity for faster the substrate with a slurry containing ceramic warm-up and catalytic materials whereby the surface area Reduced space requirement and no along the length of every channel is coated and special mounting is required impregnated with catalytic materials. Diesel oxidation catalytic converter substrates are also High flow area due to lower cell wall thickness and hence reduced pressure made from metal foil material which is fan drop folded and fashioned into a honeycomb substrate with catalyst materials in a similar Higher conversion efficiency[1,2] manner as ceramic substrates. [3] B. Catalyst: The substance which increases rate of B. Washcoat: reaction without takes part in the reaction is A washcoat is a carrier for the catalytic called as catalyst. There are different types of materials and is used to separate the materials catalysts used for conversion of pollutants. In over a large surface area. The washcoat is a this, oxides of base metals like copper, mixture of silica and alumina. The catalytic chromium, nickel, cobalt etc. and the noble materials are suspended in the washcoat prior to metals like platinum, palladium and rhodium applying to the core. Washcoat materials are are used. In this investigation, platinum is used selected to form a rough, irregular surface, as a catalyst because, at high end exhaust which greatly increases the surface area temperature base metals oxide becomes compared to the smooth surface of the deactivate and sintering occurs. Due to this, uncovered substrate. This in turn maximizes the conversion efficiency of catalytic converter catalytically active surface available to react decreases. Another advantage of platinum is with the engine exhaust. The coat must retain its good cold start performance.[1] surface area and prevent sintering of the catalytic metal particles even at high C. Washcoat: temperatures. [1-3] It is component of catalytic converter which increase the oxygen storage capacity [2]. It C. Catalyst: increases the surface area of substrate. Alloy A