Full GC-PIONA Carbon Number Analysis Performed by On-Line Process NMR Spectroscopy

Customer Application Note - Steam Cracker Optimization at BASF Ludwigshaven (pdf)

A 60 MHz process FT-NMR spectrometer has been installed on the feedstream to a naphtha cracker in several locations to provide detailed PIONA analysis, every two minutes, for input into APC/optimization packages. The NMR technique utilizes high-resolution FT-NMR proton spectra in conjunction with partial least squares modeling techniques to obtain highly linear and robust predictive models. Modeling requirements are limited and on-line models contain only around 300-500 data points with minimum model maintenance required. Single predictive models are used to predict across the entire variability range of each property. Table A shows the performance of the NMR models compared to the laboratory GC over a four month period where the NMR was available for >99.5%.

Table A - Correlation and Standard Deviation Summary of NMR-Lab GC Reproducibility

The following figures show the spectral variability observed in various naphtha streams as well as the lab-NMR agreement plots for several of the detailed PIONA parameters.

For more information on this topic please contact:

John Edwards

Manager, Process and Analytical NMR Services

Process NMR Associates LLC,

87A Sand Pit Rd

Danbury, CT 06810, USA

Tel: (203) 744-5905