Recovery of Phenylacetic Acid

Background
The client is engaged in pharmaceutical business for last three decades and has a major role in producing chemicals and drugs.

Process Overview
In one of their propriety processes for antibiotic manufacture, the aqueous effluent from the plant contained significant amount of phenylacetic acid, leading to loss of raw material and problems in the effluent treatment plant (ETP). This was a major concern as it was found to violate environmental regulations.

Customer Requirements

• Provide complete process solution for eliminating loss of phenylacetic acid, considering existing capacity and future capacity enhancement plans
• Economise proposed project cost by utilizing existing spare column

Problem analysis
The client had employed mixer settlers to extract the phenylacetic acid in toulene which was not delivering the desired results.

Solutions provided
Installation of distillation or extraction column was identified as possible solution for removing the phenylacetic acid from the effluent stream.

After collecting data from lab scale experiments on distribution coefficients of phenylacetic acid in water and toluene, a detailed study of entire system was done.

The following was concluded and recommended


• Application of liquid-liquid extraction
• Selection of Medal-Pak^® #25 as a contacting media
• Selection and design of liquid-liquid extraction internals
• Selection of packed height to match required HETP

Accordingly, the tower internals were designed and manufactured along with random packing. The random packing and tower internals were installed and commissioned.

Results achieved
The initial phenylacetic acid concentration in the effluent stream was brought down to 100 parts per million (ppm) level and also the plant capacity was increased by 50%.