catalysis for alternative energy generation pdf
In the twenty-first century, human beings face the exhaustion of fossil energy feedstock. The amount of high quality and easily accessible feedstocks is decreasing, hence the use of heavy and dirty feedstocks must perforce be explored. Poisoned crudes need to be treated in order to remove contaminants such as Nitrogen- and Sulfur-containing molecules and metals.
Thus it is imperative to consider alternative sources of energy – such as biomass – for chemicals and for transportation fuels. To underline its importance let me refer to President Bush:
President Bush launches the Hydrogen Fuel Initiative. “Tonight I am proposing $1.2 billion in research funding so that America can lead the world in developing clean, hydrogen-powered automobiles. With a new national commitment, our scientists and engineers will overcome obstacles to taking these cars from laboratory to showroom so that the first car driven by a child born today could be powered by hydrogen, and pollution-free.”
Alternative feedstocks, such as biomass and renewables, are being investigated
in biorefineries for the production of biofuels and (bio)chemicals. These feedstocks
contain many oxygen-containing molecules, hence they are more or less polar.
This poses special problems for the development of catalytic technology to treat
such new feedstocks.
Very pure and simple natural feedstocks, such as methane and light alkanes, can
also be used as the basis for production of fuels and chemicals. The fundamental
problems here are the selective activation of the C–H bond without the formation of
excessive amounts of CO2, hydrogenation of CO2, or its conversion into other
Looking through the possible technologies, it becomes clear that catalysis is the key technology to help solve the problems associated with the use of alternative feedstocks. Traditional catalysts are extremely efficient for pure, apolar oil feedstocks. Heavy and dirty feedstocks require catalysts for removal and decomposition of poisonous molecules and for removal of heavy metals. Can these processes be combined in one catalyst? This “ideal” catalyst fixes the heavy metals in such a way that they serve as catalytic sites for decomposition and removal of the poisonous molecules. In addition, the catalyst contains the acid sites necessary for cracking and isomerization of long-chain hydrocarbons.