Acetic acid measurement with NIR process cells

The annual production of acetic acid is about 1.2 Mtons. If the throughput of the plants can be increased by just 1%, then at an average price of about $500 per ton of acetic acid, extra product worth more than $6m can be produced each year if the plant runs continuously. As a result, any installation to monitor the process in real time would pay itself back within months rather than years.

Specac began the development of robust NIR cells for continuous process analysis of hazardous petrochemical process streams more than 30 years ago. One of the first applications we encountered was the measurement of corrosive and toxic chemicals used for the Acetic Acid manufacturing process, including Methyliodide, Methylacetate, Methanol, and Acetic Acid itself with high pressures of Carbon Monoxide.

Whilst laboratory studies showed encouraging results from early on, the installation of a NIR process cell on the main plant was far from straight-forward and required expertise in the measurement of the composition reliably off-line, building a robust chemometric model and most importantly a NIR process cell that can withstand the process conditions for a long period of time.

In close cooperation with our customer we introduced several innovative features to our liquid NIR process cell to ensure a reliable solution-which could then be rolled out to all major plants across the world. Needless to say that these NIR process cells are still in service today at the same location and continue to deliver exceptional value for the customer.