Norbert Rillieux

Norbert Rillieux was born on 17 March 1806 in New Orleans, the eldest of seven children in a prominent Creole family. His father, Vincent Rillieux, was a white plantation owner and engineer, and his mother was a free woman of color. He was educated in private Catholic schools in New Orleans, and his father then sent him to Paris to study at the École Centrale, where he excelled in physics, mechanics and engineering and became an instructor in applied mechanics at the age of 24.

In Paris Rillieux wrote papers on steam engines and began thinking about the way sugar was made. At the time, making sugar from cane juice was a slow, expensive and dangerous process. Rillieux realised that the vapour given off by boiling juice in one closed vacuum pan could be used to heat the next, so that the same heat did the work several times over.

Back in Louisiana he spent years developing the idea. He built early versions in the 1830s, and in 1843 he received a US patent for a double-effect evaporator, followed by a broader patent in 1846 covering all multiple-effect methods. The first successful commercial-scale installation, on Theodore Packwood's plantation south of New Orleans, proved that the system saved fuel, made the work safer and produced better sugar.

The multiple-effect evaporator spread rapidly through Louisiana and then to Mexico, Cuba and the Caribbean, and sugar makers found the machines paid for themselves with the extra profit. It is widely considered a founding invention of chemical engineering, and the same principle is still used to make sugar and other products today.

In the 1850s growing restrictions on free people of colour in Louisiana led Rillieux to move to France. There he took up Egyptology, studying hieroglyphics and working at the Bibliothèque nationale for about ten years, and he spent time defending his patents. At the age of 75, in 1881, he patented a new evaporator system that halved the cost of processing sugar beets. He died in Paris on 8 October 1894, and a bronze memorial at the Louisiana State Museum honours him as the inventor of multiple evaporation and its application to the sugar industry.