EP0304232A2

Method for the direct determination of physical properties of hydrocarbon products.

Abstract

The properties of a product and/or the yield of the product from a hydrocarbon conversion or separation process are determined from the NIR (Near Infra Red) spectrum of the feedstock by a method which comprises the following steps: (a) determining with an IR spectrometer the absorbance of the feedstock at a certain number of frequencies in the spectral range 16667 to 3840 cm⁻¹, preferably 12500 to 3840 cm⁻¹, most preferably 4760 to 4999 cm⁻¹ starting from a defined base line, and(b) determining the property by applying a correlation between the property and the absorbance values, the correlation being determined experimentally by multivariate regression, depending on the type of spectrometer used, the property required, and the frequencies used.

EP0304232A2, drawing sheet 1
Sheet 1 of 10

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Term ended

Projected expiry passed 11 August 2008, 18.1 years ago.

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22 claims: 16 independent, 6 dependent

  1. 1
    A method for the determination of the properties of the product and/or the yield of the product in a hydrocarbon conversion or separation process characterised by the fact that the method comprises the following steps:(a) determining with an IR spectrometer the absorbance of the feedstock at a certain number of frequencies in the spectral range 16667 to 3840 cm⁻¹, starting from a defined base line, and(b) determining the property by applying a correlation between the property and yield of the product and the absorbance values of the feedstock, the correlation being determined experimentally by multivariate regression, depending on the type of spectro­meter used, the property required, and the frequencies used.
  2. 3
    A method according to either of the preceding claims wherein the frequencies are in the spectral range 12500 to 3840 cm⁻¹.
  3. 5
    A method according to any of the preceding claims characterised by the fact that the frequencies used are selected from the following:4670 cm⁻¹ 4640 4615 4585 4485 4405 4390 4385 4332 4305 4260 4210 4170 4135 4100 4070 4060 4040
  4. 6
    A method according to any of the preceding claims characterised by the fact that the base line is taken as 4780 cm⁻¹.
  5. 7
    A method according to any of the preceding claims wherein the spectrometer is linked to a signal processing device to permit numerical treatment of the spectrum.
  6. 9
    A method according to any of the preceding claims wherein the method is on-line and in real time.
  7. 10
    A method according to any of the preceding claims wherein the correlation contains linear terms, quadratic terms and homographic terms.
  8. 11
    A method according to any of the preceding claims wherein the hydrocarbon conversion process is a catalytic reforming process and the properties are selected from the following:yields of gasoline (C₅⁺), hydrogen and gas, octane numbers (clear or leaded), vapour pressure and density.
  9. 12
    A method according to any of the preceding claims wherein the hydrocarbon conversion process is a catalytic reforming process, characterised by the fact that the method comprises the further steps of:(c) carrying out differential spectrum measurements in the same range and at the same frequencies on the feedstock and the product,(d) applying a correlation between the differential spectrum and the octane number gain, the correlation being determined experimentally by multivariate regression analysis,(e) comparing the sum of the two values thus determined (octane number and octane number gain) with a desired objective, and(f) modifying the operating conditions of the catalytic reformer until the determined octane number gain is in agreement with the desired octane number gain.
  10. 13
    A method according to either of claims 11 or 12 wherein the frequencies used are selected from the following:4670 cm⁻¹ 4485 4332 4305 4210 4100 4060 4040
  11. 14
    A method according to any of claims 1 to 10 wherein the hydrocarbon conversion process is a selective hydrogenation process and the property is the maleic anhydride number of the product.
  12. 15
    A method according to any of claims 1 to 10 wherein the hydrocarbon conversion process is a catalytic hydrocracking process and the properties are selected from the following:the total conversion of the feedstock to product and the conversion to gasoline.
  13. 17
    A method according to any of claims 1 to 10 wherein the hydrocarbon conversion process is a catalytic cracking process.and the properties are selected from the following:(i) the conversion of the feed to gasoline and the yield of residue in the product,(ii) the density, research octane number (RON) and motor octane number (MON) of clear and leaded gasoline from the cracking process.
  14. 19
    A method according to any of claims 1 to 10 wherein the hydrocarbon conversion process is a visbreaking process and the properties are selected from the following:yield of the gas oil product, the viscosity, specific gravity and xylene equivalent of the residue, and the conversion limit.
  15. 20
    A method according to any of claims 1 to 10 wherein the hydrocarbon separation process is a distillation process and the properties are selected from the following:(i) the quantitative composition of a mixture of crude oils constituting the feedstock when the distilland is known to be a blend of crude oils,(ii) the yields of products obtained,(iii) the densities and viscosities of the products,(iv) the cetane number, aniline point, cloud point and KUOP characterisation factor of the gas oil product,(v) the n-paraffinic, isoparaffinic, cycloparaffinic and aromatic content of the gasoline and the research octane number (RON) and motor octane number (MON) of clear and leaded gasoline.
  16. 21
    Apparatus for carrying out a method according to any of the previous claims comprising an infra red spectrometer and a computer characterised by the fact that the infra red spectrometer is linked to the computer program in such manner that the property may be determined continuously and in real time.
Independent claims16