Abstract: Reformulated gasoline (RFG) testing recently required by EPA involves measuring sulfur, olefin, aromatic contents, Reid Vapor Pressure (RVP), and benzene, distillation properties, plus total air pollutants (TAPs), volatile organic carbon (VOC), and nitrogen oxides (NOx). Measuring driveability, although not required, is desirable. All of these tests can be conducted by spectrometer, preferably in the IR range, more preferably in the NIR range, and most preferably by a single instrument operating at high-correlation wavelengths. Importantly, VOC, TAP, NOx, and RVP may be correlated to IR absorbance at certain bands. Statistical methods including PLS, MLR, PCR, and neural networks can be used and derivatives of first, particularly second, or other orders can be used. Results can be displayed on a single screen.
Type:
Grant
Filed:
December 19, 1997
Date of Patent:
October 31, 2000
Assignee:
Marathon Ashland Petroleum
Inventors:
William T Welch, Roy R. Bledsoe, Brian K. Wilt, Michael B. Sumner
Abstract: A Fourier-Transform Raman spectrometer was used to collect the Raman spectra of (208) commercial petroleum fuels. The individual motor and research octane numbers (MON and RON, respectively) were determined experimentally using the industry standard ASTM knock engine method. Partial Least Squares (PLS) regression analysis can be used to build regression models which correlate the Raman spectra (175) of the fuels with the experimentally determined values for MON, RON, and pump octane number (the average of MON and RON) of the fuels. Each of the models was validated using leave-one-out validation. The standard errors of validation (SEV) are 0.415, 0.535, and 0.410 octane numbers for MON, RON, and pump octane number, respectively. By comparing the standard error of validation to the standard deviation for the experimentally determined octane numbers, it is evident that the accuracy of the Raman determined values is limited by the accuracy of the training set used in creating the models.
Type:
Grant
Filed:
September 30, 1996
Date of Patent:
April 6, 1999
Assignees:
Ashland Inc., Old Dominion University Research Foundation
Inventors:
John B Cooper, Roy R Bledsoe, Jr., Kent L Wise, Michael B Sumner, William T Welch, Brian K Wilt
Abstract: A distributed Bragg reflector (DBR) diode laser is used as excitation source for fiber optic Raman spectroscopy utilizing charge coupled device (CCD) detection and an image-corrected spectrograph. The DBR diode laser is superior to index guided diode lasers (Fabry-Perot) for elimination of mode hopping, elimination of frequency hysteresis as a function of both temperature and current changes, and reduction in laser broadband emission. These advantages allow the DBR laser to be used in industrial process control applications which are too demanding for index guided diode lasers.
Type:
Grant
Filed:
May 29, 1996
Date of Patent:
January 5, 1999
Assignee:
Ashland Inc
Inventors:
John B Cooper, Philip E. Flecher, William T. Welch
Abstract: Benzene and substituted aromatic hydrocarbons can be predicted within .+-.0.31% vol or better, using Raman NIR spectroscopy and multivariate analysis, with optional fiberoptics multistreaming, preferably with Partial Least Squares regression analysis. The resulting signal can be used to control concentration of such compounds in product to desired levels.
Type:
Grant
Filed:
May 1, 1995
Date of Patent:
November 4, 1997
Assignee:
Ashland Inc.
Inventors:
John B. Cooper, Philip E. Flecher, Jr., William T. Welch