The client was interested in achieving the liquid-liquid extraction of an organic acid from an aqueous feed containing approximately 30-45% organic acid. The desired raffinate concentration was less than 1% organic acid. Notably, in this process, the aqueous phase is the heavy phase and continuous, whereas the solvent is the light phase and dispersed.
Koch Modular’s key to providing optimized extraction columns is performing comprehensive proof of concept pilot testing. The production column in this case was designed based upon successful pilot plant tests in a 3” diameter, glass-shell SCHEIBEL®Column.
Drums of organic acid feed and a mixed solvent were provided by the client. Data for the design of a single SCHEIBEL®Column capable of handling the capacity of two existing POD trains (total of 4 PODs) plus the additional capacity for plant expansion was collected. Optimal column and operating conditions—including total throughput, agitation speed, and the number of agitated stages—were determined.
Koch Modular provided a 112” inner diameter, 30-stage SCHEIBEL®Column guaranteed to process up to 150,000 lb/hrof crude organic acid feed and 160,000 lb/hrof solvent. The mixed solvent contains less than 0.65% organic acid. At this solvent to feed ratio, the SCHEIBEL®Column reduces the organic acid content from 30-45% in the crude feed to less than 0.65% in the aqueous raffinate.
The provided column achieves 20% additional capacity compared to the client’s existing POD centrifugal extractors. It is designed for a 20+ year life cycle with little maintenance, a significant improvement compared to the high maintenance for the existing system.
The column installation and start-up were successful, and it has been running ever since with no issues reported. With the centrifugal extractors no longer operating, a large yearly maintenance cost savings was realized.