Application Brief: Water Breakthrough Detection

Tetrahydrofuran (THF), is widely used throughout many industries and most commonly associated with the production of Spandex and varnishes. THF is also a common solvent traditionally used with PVC. It is estimated that the manufacturing of THF will exceed 800,000 tons this year.

The recovery and reclamation of THF is often necessary for process efficiency or for environmental compliance. The most common method of recovery involves distillation to remove water from the THF. The recovered dry THF must be cooled before being sent to a storage vessel as the final product. Shell-in-tube heat exchangers are used to cool the THF and water is often used as the cooling fluid. If the heat exchanger has leak points that fail over time, the cooling water will enter the THF stream.

Online continuous monitoring of the water concentration in the THF after the heat exchanger is used to determine if a leak has occurred.

In the past, a lab method using grab samples and Karl Fisher Titrations have been the method of choice. This lab method inherently suffers from inaccuracy, inconsistency, slow response time, and it requires operators and consumable reagents.

The Applied Analytics Microspec IR analyzer (MCP-200) installed on the outlet of the heat exchanger continuously measures moisture content at PPM levels, to identify upsets in real time. If a water contamination (leak) does occur the stream can be diverted immediately to recovery before contaminating the previously stored product.

The MCP-200 employs a solid state NDIR detector with no moving parts and is a fully automated online system that does not require reagents or consumables. The alarm on water content (PPM) is user adjustable. Different output signals are available including a 4-20mA signal to the DCS or a relay connected directly to a shutoff valve. And as always Applied Analytics analyzers are safe, require minimal maintenance and allow for AAI’s engineers to remotely access the analyzer.