Impact of the Houdry Invention

The most dramatic benefit of the earliest Houdry units was in the production of 100-octane aviation gasoline, just before the outbreak of World War II. The Houdry plants provided a better gasoline for blending with scarce high-octane components, as well as by-products that could be converted by other processes to make more high-octane fractions. The increased performance meant that Allied planes were better than Axis planes by a factor of 15 percent to 30 percent in engine power for take-off and climbing; 25 percent in payload; 10 percent in maximum speed; and 12 percent in operational altitude. In the first six months of 1940, at the time of the Battle of Britain, 1.1 million barrels per month of 100-octane aviation gasoline was shipped to the Allies. Houdry plants produced 90 percent of this catalytically cracked gasoline during the first two years of the war.

The original Houdry process embodied several innovative chemical and engineering concepts that have had far-reaching consequences. For example, the improvement of the octane rating with catalytic processes showed that the chemical composition of fuels was limiting engine performance. Further, aluminosilicate catalysts were shown to be efficient in improving the octane rating because they generated more highly branched isoparaffins and aromatic hydrocarbons, which are responsible for high octane ratings. From an economic standpoint, the catalysts could be regenerated after a short usage time, thus returning the catalyst to full activity without having to add additional material.

The original fixed-bed Houdry Process units have been outmoded by engineering advances that transformed the fixed-bed to more economical fluidized-bed systems and introduced the use of crystalline aluminosilicate catalysts to provide higher yields of gasoline. Yet it is remarkable that, seventy years after Houdry's discovery of the catalytic properties of activated clay to convert petroleum fractions to gasoline, the same fundamental principles that made the process a success are still the primary basis for manufacturing gasoline worldwide.