NIR Spectral Stability Prediction for Hydrocarbon Streams
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Solution Overview
Problem
Current methods for determining hydrocarbon process stream stability, particularly asphaltene stability, are time-consuming and inefficient, especially when dealing with frequent changes in crude oil feed types, limiting the ability to optimize cracking processes.
Innovation Solution
A method using near-infrared (NIR) spectral absorbance measurements combined with a correlation model to predict stability, which involves creating a dataset from measured absorbance and wave numbers in the NIR spectrum, and applying statistical techniques like Principal Component Analysis and Partial Least Squares to develop a predictive model for stability calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heptane phase separation method is used to determine asphaltene stability, then measurement precision is improved, but loss of time increases and productivity decreases
Solution Approach 1:
The patent replaces the mechanical/chemical heptane phase separation method with near-infrared spectroscopy (NIR), an optical detection method. The NIR system measures absorbance spectra of the hydrocarbon process stream directly without requiring heptane addition or phase separation, thereby eliminating the time-consuming manual operations while maintaining measurement capability through spectral analysis of asphaltene-related compounds
Solution Approach 2:
The patent creates a correlation model that copies the stability measurement function from the traditional heptane method. By developing empirical correlations between NIR spectral parameters (absorbance ratios at specific wavelengths) and stability values obtained from reference heptane phase separation tests, the system replicates the measurement capability through a different physical basis, enabling rapid prediction without the time-intensive reference method
2Measurement precision
If heptane phase separation method is used to determine asphaltene stability, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent replaces the mechanical/chemical heptane phase separation method with near-infrared spectroscopy (NIR), an optical detection method. The NIR system measures absorbance spectra of the hydrocarbon process stream directly without requiring heptane addition or phase separation, thereby eliminating the time-consuming manual operations while maintaining measurement capability through spectral analysis of asphaltene-related compounds
Solution Approach 2:
The patent enables continuous monitoring of asphaltene stability by implementing online NIR spectroscopy measurement. The system continuously acquires spectral data from the process stream and updates stability predictions in real-time, allowing for continuous process optimization rather than intermittent batch testing. This continuous measurement capability directly improves productivity by enabling dynamic adjustment of cracking conditions
3Measurement precision
If multiple dilutions and titrations are performed for stability analysis, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential measurement information needed for stability assessment from the complex heptane phase separation procedure. By identifying that NIR absorbance ratios at specific wavelength pairs correlate with stability, the system isolates the critical measurement parameter (spectral absorbance ratio) and eliminates all other procedural steps including multiple dilutions, heptane titrations, and manual endpoint determinations, thereby simplifying the overall analysis procedure
Solution Approach 2:
The patent creates a correlation model that copies the stability measurement function from the traditional heptane method. By developing empirical correlations between NIR spectral parameters (absorbance ratios at specific wavelengths) and stability values obtained from reference heptane phase separation tests, the system replicates the measurement capability through a different physical basis, enabling rapid prediction without the time-intensive reference method
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a faster, more efficient, and user-friendly method for analyzing hydrocarbon process streams, reducing the time required and skill needed, enabling online optimization of cracking processes by predicting stability values accurately.
Implementation Method 1
measuring an absorbance value for the additional sample by using the second spectrum to obtain a near infrared spectrum of the additional sample
Data Source
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AI summary
A method of predicting the stability of a hydrocarbon process stream is disclosed and claimed. The method includes obtaining samples from one or more process streams and measuring the actual stability and the near infrared spectral absorbance of those samples. A classification model is initially developed to identify sample subsets and correlation model is created using the stability and absorbance data by inserting that data into a mathematical function. Online or offline measurements are then taken from the hydrocarbon process stream, the classification model is used initially to identify the subset and corresponding correlation model is used to predict the stability of the stream.