The National Environmental Engineering Research Institute (NEERI), Nagpur, has developed a non-noble metal-based, two-way catalytic converter technology for the control of exhaust emissions from petrol-driven vehicles.

The catalytic converter consists of a ceramic honeycomb support coated with a perovskite type catalyst housed in a suitably designed, non-corrosive metallic housing. The device is fitted to the exhaust system of a petrol-driven vehicle and catalytically converts the harmful carbon monoxide (CO) and hydrocarbon (HC) emissions to carbon dioxide and water. The use of non-noble metal-based catalyst makes the device cost-effective and lead tolerant compared to the noble metal-based catalytic converts.

The support used is a cordierite, monolith honeycomb with approximately 400 cpsi of channel density. The surface area of support has been improved to the desired level by high surface area alumina washcoating technique developed in-house.

The catalystused is of perovskite type synthesised from non-noble metals and promoted by other metals (patents filed). The catalyst coated on alumina washcoated support provides good adherence and high surface area even at elevated temperatures.

Vehicle specific modifications in the catalytic converter have also been incorporated using mass transfer, pressure drop and thermal gradient modelling to optimise the reactor dimensions. These specific designs ensure minimum pressure drop across the converter and adequate retrofit mechanisms for the existing Indian vehicles.

The catalytic converter is fitted in the exhaust system after the exhaust manifold of petrol-driven vehicles. Exhaust flowing in the reactor shell, through the honeycomb channels, comes into contact with the coated catalyst surface.

The CO and HC contents of exhaust get catalytically converted into carbondioxide and water. This oxidation reaction facilitates the catalyst surface in a temperature range of 300 degree centigrade to 650 degree centigradein the converter shell.

Various physical/chemical test and performance evaluation of catalytic converter have been carried out. Alumina washcoated supports and catalyst were characterised for the surface area, phase formation and thermal stability.

The attachment of catalytic converter to vehicle exhaust system would reduce the CO and HC emissions to around 70 per cent at warm idling conditions of the engine. The pressure drop across the converter has been determined and is observed to be well below the tolerable limit of 70 cm of water column (at maximum rpm). The catalyst is lead tolerant and can be used for leaded and unleaded gasoline.

Applications:
Catalytic converter is the only techno-economically feasible device to effectively control the exhaust emissions from petrol-driven vehicles. The use of catalytic converter in the vehicles running on petrol is essential to control the exhaust emissions and to meet future auto-exhaust emission standards.

Estimated cost of catalyticconverter:
Rs 5,000 per unit.For further details contact: National Research Development Corporation (NRDC),`Anusandhan Vikas', 20-22, Zamroodpur Community Centre, Kailash Colony Extension, New Delhi-110048. Phone: 6417942, 6434265, Fax: 011-6460506; E-mail: nrdc@x400.nicgw.nic.in.

Sidbi on Internet

The Small Industries Development Bank of India has launched its website http://www. sidbi. com.All information about Sidbi is available on the website. The website contains the bank's functions, range of products and services available for development of the small scale industry. Users can also seek clarifications/advice on points raised.

Sidbi has the mandate of meeting the financial needs of small companies. It is ranked among the top 25 development banks of the world.