Introduction to the world's leading edge catalyst technology(2)

The development of new, high-efficiency catalysts is the basis for the leapfrog development of the petroleum and chemical industries. In recent years, nearly 50% of the international research on catalysis has been focused on the development of new catalysts, and increasing attention has been paid to them. 

Another significant feature is that the development of new catalysts is closely linked to environmental friendliness, i.e., catalysts and catalytic technologies are required to produce essential products for life while eliminating pollution at the source. From the number of research papers included in the international authoritative search system, the reports on new catalysts have increased at least 15 times from l990 to 1999, among which new catalysts such as solid acid, solid base and selective oxidation have been developed extremely rapidly. 

Solid acid catalysts are a new class of catalysts developed internationally in recent years, and they have become the most strongly developed class of new catalysts because they can replace traditional sulfuric acid catalysts in important reactions such as esterification, alkylation and isomerization, and eliminate pollution from the source.

Homogeneous bases catalyzed a considerable proportion of chemical synthesis, such as epoxide ring-opening addition synthesis of surfactants, ester exchange preparation of fine chemicals, etc., but due to serious pollution problems caused a bad impact on the environment. In recent years, replacing traditional liquid base catalysts such as sodium hydroxide with solid bases has become an inevitable development trend.

Due to the requirements of catalyst activity, economy and environmental protection, the research focus of coal liquefaction catalysts has been concentrated on the preparation and incorporation method of ultrafine particle dispersed iron-based catalysts, and future research topics still need to be done in the way of introducing catalysts by ion exchange, improvement of direct impregnation method, application of nanoscale iron oxide and modified (sulfide) iron oxide, and incorporation of low concentration of metals that can promote the improvement of iron-based catalyst activity.

With the application of new technologies for automobile engines and the increasingly stringent environmental regulations, the following development trends will be observed for automobile exhaust gas conversion catalysts. First, in order to improve fuel combustion efficiency and reduce CO emissions, automobile engines will gradually adopt lean combustion technology. According to reports, the fuel economy of this engine is 20% to 25% higher than that of conventional engines. 

Due to the excess of oxygen, the NOX reduction and removal becomes a technical problem. The solutions being studied include NOX capture, selective reduction and electro-thermal catalysts, etc. The technology is expected to be industrialized in Europe in the near future. The next step is to design catalysts that can quickly preheat the engine during cold start.

In Europe and North America, vehicle emissions of pollutants are mainly caused by early emissions before the catalytic converter is warmed up. In the coming years, more stringent emission limits that will come into effect in the U.S., Europe and Japan will mainly target the purification of exhaust gases 20 to 30s before start-up. 

In addition, automotive exhaust gas reforming catalyst manufacturers are working to reduce the amount of precious metals in their catalysts. The third is the elimination of H2S emissions. Vehicles with newly installed catalytic converters produce an unpleasant odor when driving, due to the sulfur accumulated in the catalytic converter in the form of H2S emissions, and a suitable solution is currently under study.