Norbert Rillieux (1806-1894) was the inventor of the multiple-effect vacuum evaporator, which revolutionized the processing of sugar. He gained recognition as one of the prime architects of the modern sugar industry. Techniques developed by Rillieux are now commonly used in the reduction or concentration of saturated liquids into super-saturated liquids, high density solids, or dry granules.

Rillieux's invention has been adopted for the production of any number of solids and reduced liquids whose products are sensitive to heat. The manufacture of such commodities as condensed milk, soaps, gelatins and glues, the recovery of waste liquids in distilleries and paper-making factories, and the processing and production of petrochemicals all have used Rillieux's basic invention, or devices that are based on his process.

Early Years and Education

Norbert Rillieux was born in New Orleans, Louisiana on March 17, 1806. His parents were Vincent Rillieux, a white man, and Constance Vivant, a freed black slave. Vincent Rillieux was a successful engineer and inventor, who recognized the talent of his son at an early age and sent him to Paris for his education.

By 1830, Rillieux was an instructor in applied mechanics at L'Ecole Centrale in Paris, and had published a series of papers on steam engines and the economies of steam generation. P. Horsin-Deon, a French sugar technologist, engineer, and secretary to Rillieux, reported that Rillieux had developed the theory of the multiple-effect evaporator at this time. However, it required 12 years of work and several unsuccessful attempts before he mastered the process and built a successful, factory-scale multiple-effect vacuum evaporator.

Rillieux was one of several inventors based in Europe who worked on improving a British invention of 1812 for the processing of sugar. The British invention was a single-effect evaporator that saw widespread use in Europe. The single-effect evaporator was used for the crystallization of sugar. It did not replace the numerous open cauldrons and their accompanying fires. With his knowledge of the uses of steam and vapors, Rillieux devised an evaporator system that contained the latent heat from one stage, and transferred and used that heat in the successive stages. Other inventors worked on similar paths, but Rillieux developed a vacuum chamber to enclose condensing coils used in the successive stages and, with this modification, became the first to accomplish multiple-effect evaporation. His innovation was the use of a vacuum chamber to house the condensing coils. That helped him to lay the foundation for all industrial evaporation processes.

Returned to New Orleans

Rillieux was not successful in promoting his idea to French sugar processors, but a fellow native of New Orleans, Edmund Forstall, became of aware of his growing reputation in the uses of steam and his growing proficiency in engineering, and asked Rillieux to return to his hometown as the chief engineer of a sugar refinery. That arrangement did not last long. After breaking his ties with Forstall, Rillieux and two colleagues built what is considered to be the first attempt at a multiple evaporator in 1834 at a plantation owned by Zenon Ramon. Rillieux built another multiple effect evaporator in 1841, but that device also did not succeed.

A plantation owner by the name of Theodore Packwood encouraged Rillieux to put a multiple effect evaporator on his plantation south of New Orleans in 1843, and engaged the Philadelphia manufacturing firm of Merrick and Towne to produce the device. That evaporator is considered the first successful, commercial-scale, multiple effect evaporator put into practical use. It was operating by 1845.

A Successful Invention

In 1843, while overseeing the building of the device for Packwood, Rillieux received a patent, U.S. 3,237 (1843), for a double-effect evaporator. He built his invention on that patent, that was superceded by his more sweeping patent of 1846, covering all multiple-effect evaporator techniques. News of the success of the Packwood evaporator spread quickly. By 1849, 13 sugar refineries were reported by the DeBow crop report to be using the "Rillieux patent sugar boiling apparatus."

An employee from Merrick and Towne, the Philadelphia manufacturing company that produced the Packwood evaporator, stole the designs for Rillieux's device and took them back to his native Germany, where he began producing evaporators from a factory in Magdeburg. Rillieux's idea finally was successful with French sugar processors, when a pirated version of his evaporator was installed at a beet sugar factory in the French village of Cuincy in 1852. However, the European version of Rillieux's device was not accompanied by Rillieux's knowledge of the fundamental scientific principles on which it was based. It did not perform as well as the evaporators that Rillieux had installed.

Rillieux reached the pinnacle of his success between 1845 and 1855, when his invention revolutionized the entire sugar manufacturing process. During that period, Rillieux's evaporator replaced the process that had been in use for centuries. Rillieux also developed additional improvements and engineering accessories for sugar refining, that have long been considered essential components of sugar processing.

While he was experiencing his years of greatest professional success, as person of mixed race, Rillieux was subjected to increasing racial intolerance. Restrictions that limited the movements of free persons of color throughout the southern United States were broadened at that time. Tensions were growing that would eventually erupt in the American Civil War. It is reasonable to assume those swelling tensions affected Rillieux. By 1855, free persons of color were no longer permitted to move freely about the streets of New Orleans. Although they paid taxes, they could not use the New Orleans public school systems. Nor could they stop within the New Orleans city limits before they presented the guarantee of some white man. If they did not leave the city when ordered to, they could be imprisoned and set to hard labor.

Those restrictions, coupled with the rapid decline of the sugar industry in Louisiana during the Civil War, are seen to have contributed to Rillieux's decision to return to Paris. Since he was considered to be quite successful, it was assumed that he was in comfortable circumstances when he left New Orleans. The year of his departure remains in question, but he was again living in Paris sometime between 1861 and 1865.

Returned to France

On his return to Paris, Rillieux dropped from sight for some time. It is believed that he temporarily lost interest in sugar refining. Instead, he turned to the study of Egyptology, which was then a fashionable pursuit among Parisian intellectuals. Rillieux worked with the family of Jean François Champollion, the translator of the Rosetta Stone, deciphering Egyptian hieroglyphics through 1881.

At the age of 75, Rillieux returned to sugar refining. He developed and patented a system for heating thin syrups. This innovation is still used in cane and beet sugar factories today. Rillieux later lost patent rights to what eventually was called the "French Process" for sugar refining. The process combined his ideas and patents on the extensive uses of steam to power multiple vacuum evaporation and the heating of thin juices and vapor boiling techniques that did not damage syrups or sugars. With the loss of rights to these important techniques, it is reported by Horsin-Deon that Rillieux died in France in 1894, a broken-hearted man. He was buried at the churchyard of Per La Chaise. His wife, Emily Cuckow, was buried next to him in 1912.

Rillieux has been called a scientific genius and, as a visionary who left his colleagues far behind, one of the most distinguished engineers of all time. While not widely known nor widely acclaimed, chemists and chemical engineers and sugar technologists who are familiar with Rillieux and his work have generally used strong words of praise for him and his inventions, and have cited the widespread applications of the basic techniques he developed.

Further Reading

• The Beet Sugar Story, United States Beet Sugar Association, 1959.
• Negro History Bulletin, April 1957, p. 159-163.
• Van Hook, Andrew, Sugar: Its Production, Technology, and Uses. Ronald Press Company, 1949.