Process and apparatus for analysis of hydrocarbons by near-infrared spectroscopy

In a process for the control of hydrocarbons and substituted hydrocarbons in complex mixtures comprising as components;

• paraffins, aromatics, naphthenes, or olefins to determine component concentration, the improvement comprising in combination:
• a. measuring the infrared absorbance at at least three wavelengths comprising at least one wavelength in each of two or more of any of the following bands:
• 1672-1698, 1700-1726, 1622-1650, 2064-2234, 1092-1156, 824-884, 1656-1692, 880-974, 1152-1230, 1320-1380, 1470-1578, 1614-1644, 1746-1810, 1940-2000, and/or 2058-2130 nm.
• b. taking each of the absorbances measured, or a mathematical function thereof,
• c. performing statistical treatment using said absorbances or functions as the individual independent variables,
• d. assigning and applying weighting constants or their equivalents to said independent variables,
• e. applying the above steps using known compositions in a calibration step to calibrate the instrument and determine said weighting constants or equivalents,
• f. repeating said steps a. and b. with unknown compositions, applying the weighting constants or equivalents determined during said calibration with known compositions to output a signal or signals indicative of a paraffin, aromatic, naphthene, or olefin (PIANO) component or components concentration,
• g. controlling a blending hydrocarbon refining, or chemical process by apparatus responsive to said output signal.

In a process for the analysis and control of hydrocarbons and substituted hydrocarbons in complex mixtures comprising as components;

• paraffins, aromatics, naphthenes, or olefins to determine component concentration, the improvement comprising in combination:
• a. measuring the near infrared absorbance at at least three wavelengths comprising at least one wavelength in any two of the following bands:
• 1672-1698, 1700-1726, 1622-1650, 2064-2234, 1092-1156, 824-884, 1656-1692, 1152-1230, 1320-1380, 1470-1578, 1614-1644, 1746-1810, 1940-2000, and 2058-2130 nanometers (nm).
• b. outputting a periodic or continuous signal indicative of a derivative of said absorbance in said wavelength or wavelengths in said band, or of a combination of mathematical functions thereof;
• c. performing statistical treatment using said signal derivative of said absorbance or functions as the individual independent variables,
• d. assigning and applying weighting constants or their equivalents to said independent variables,
• e. applying the above steps using known compositions in a calibration step to calibrate the instrument and determine said weighting constants or equivalents,
• f. repeating said steps a. and b. with unknown compositions, applying the weighting constants or equivalents determined during said calibration with known compositions to output a signal or signals indicative of a paraffin, aromatic, naphthene, or olefin (PIANO) component or components concentration,
• g. controlling a blending, hydrocarbon refining or chemical process by apparatus responsive to said output signal.