On-line determination of the molar ratio between methanol and isobutylene in feedstock of a methyl tertiary butyl ether production plant using near-infrared spectroscopy.

The molar ratio between methanol and isobutylene (MRMI) is very important to the operation of methyl tertiary butyl ether (MTBE) production units. A new on-line near-infrared (NIR) analytical system was integrated for monitoring the MRMI in real time and was successfully applied in a rubber plant. Calibration models for methanol and isobutylene were established using partial least squares (PLS). The sample temperature effect on the performance of the models is discussed. The MRMI is calculated by methanol content and isobutylene content predicted by NIR. A large benefit has been obtained by the user through controlling the operation of the unit according to the monitoring of the MRMI of the feedstock in real time.