Givaudan Corporation of Clifton, NJ, needed vacuum-generating equipment for their new distillation center. The equipment would increase manufacturing capacity of rare and costly perfume ingredients and essential oils made in small quantities.
Because they are highly time/temperature sensitive, the specialty chemicals are purified at reduced temperatures by vacuum distillation. Thus, reliability of the vacuum source was of utmost importance. And because trace impurities could change fragrance characteristics substantially, vacuum equipment was sought that would not add oil, lubricant or other contamination to the highly purified essential oils.
The plant has 10 stills, ranging from 150 to 1000 gallons, permitting flexibility in batch sizes for the various chemicals. The company’s output is two million lb/yr, but shipments are made in 55 gallon drums because the materials are varied and special. They include fragrance constituents such as eugenol, lilal, linalool, geraniol, citranol, and other essential oils and aroma chemicals.
Ten ejector vacuum systems were installed on the specified 10 reactor vessels. The four stage ejectors have no moving parts and require no oil or lubricants. They have low maintenance requirements and are engineered for trouble-free service. Vacuums to 5 micron Hg absolute can be achieved with this type of equipment. The plant generally operates their ejectors in the one millimeter range, as their essential oil products are volatile.
Five of the stills have been in production since mid-April, 1980. All 10 of the jet vacuum systems have been tested and determined to be operating effectively. According to the company’s engineers, the chief operating problem in start-up is the clogging of steam jets from dirt in the steam pipes. Once the lines are cleaned out the equipment operates dependably and efficiently, according to the engineers.
The four-stage steam jets are capable of handling 5 lb/hr of air at one millimeter. There is a shell and tube intercondenser between the second and third vacuum stages, and an aftercondenser at the atmospheric (first) stage. The condensers are connected to a barometric leg hotwell, so that any trace organics and all steam condensate are channeled to this collector.
All gases are vented to the atmosphere. The steam jets are mounted in the second story of the building, higher than 34′, the height of the barometric leg. Seven units are routed to one hotwell, and three to another.
Givaudan engineers have had experience with steam jets as a vacuum source. When specifying equipment for the new plant, they selected designs that were known for reliability of operation. The company uses 30 to 40 sets of steam jets in other areas of its Clifton plant. Now that they have seen the units in operation, the engineers are pleased with the performance of the steam jets that are in production. The units’ dependability allows vacuum distillation to be carried out at the highest efficiencies possible for the products and the distillation columns used.
Distillation efficiency means obtaining high yield of the desired products and minimizing upper and lower cuts, which add to disposal problems. This is economically important to a producer of high value, low volume specialty products.