Gasoline Catalyst Technologies

Catalysis and Automotive Pollution Control III Studies in Surface Science and Catalysis, Vol. 96 1995 Elsevier Science B.V. 

The results of a development program for Pd-only and Pd/Rh automotive emission control catalysts are discussed. A review of former experiences with Pd-containing systems, especially their poor tolerance against lead and sulfur poisoning is given. Model gas experiments were conducted with improved Pd-based catalysts. Not only the activity to convert simultaneously CO, NO and hydrocarbons (HC) was investigated, but also the formation of so-called secondary emissions such as N2O or NH3. 

The majority of modem gasoline fueled passenger cars is equipped with so-called closed-loop three-way catalysts to aftertreat their exhaust gases [1], The purpose of this system is to convert simultaneously carbon monoxide, hydrocarbons and nitrogen oxides by means of a precious metal based heterogeneous catalyst, whereby the engine s air-to-fliel-ratio is controlled to 

Due to a number of improvements in fuel quality, significantly lower lead and sulfur contents and improved engine management systems, Pd-containing catalysts gain more and more interest. 

In the last 10 years the gasoline sulfur and lead content in Europe and the United States decreased significantly. Table 1 illustrates the situation [7,11]. 

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D Amico, V.J. et al. (2002) The AlkyClean process a new solid add catalyst gasoline alkylation technology. 

All these systems use lean operation to achieve the improved fuel consumption. However as NOx emission standards are lowered to meet environmental concerns this presents a challenge to the conventional 3 way catalyst technology used on gasoline engines and to the technologies described above for diesel engines. 

Catalyst technology has shifted from iron as the active metal to cobalt and it has been suggested that all new plants in the immediate future will have cobalt catalysts, preferred because of their inherent stability, excellent activity, compatibility with slurry reactor operations, and ability to make waxy products as well as diesel and gasoline.16... 

Fischer Tropsch technology is best exemplified by the SASOL projects in South Africa. After coal is gasified to a synthesis gas mixture, it is purified in a rectisol unit. The purified gas mixture is reacted in a synthol unit over an iron-based catalyst. The main products are gasoline, diesel fuel, and jet fuels. By-products are ethylene, propylene, alpha olefins, sulfur, phenol, and ammonia which are used for the production of downstream chemicals. 

Any mechanical revamp to improve the unit yields should always begin with installing an efficient feed and catalyst distribution system. This is the single most-important component of the FCC unit. An efficient feed and catalyst injection system maximizes gasoline yield and conversion at the expense of lower gas, coke, and decant oil and allows downstream technology to perform at its full potential. 

Crude oil is by far the most important resource for modern society. Approximately 450 refineries in the world convert crude oil into transportation fuels (gasoline, diesel, kerosene), lubricants and feed stocks for all sorts of chemicals. Catalysts play a key role in these processes [J.A. Moulijn, M. Makkee and A. van Diepen, Chemical Process Technology (2001), Wiley, Chichester],... 

At present the NSR concept is only applicable in markets where low-sulfur fuels (30 ppm S or less) are available, such as in Japan and Sweden. The first NSR catalyst was applied by Toyota in 1994 and currently (end of 2000) about 300.000 cars in Japan have been equipped with it. As the sulfur specifications of fuels is to be tightened, NSR technology will find wider application, as it allows gasoline-fueled engines to operate under conditions of increased fuel efficiency, implying that CO2 emissions will be lower. 

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