Abstract: A method of determining the content of insolubles in oils using (a) a relation for measuring either absorbance or transmittance from the intensity of transmitted light, (b) a calibration curve for determining the content of insolubles on calibration curve in an oil sample of interest from a measured intensity of scattered light as obtained with a standard sample, (c) the first correlationship for determining the first coefficient of quantification for correcting the effects of the color intensity of the oil sample and the content of insolubles in it, and (d) the second correlationship for determining the second coefficient of quantification for correcting the effects of the particle size distribution of the insolubles and an apparatus for determining the content of insolubles in oils including basically a light source, an interference filter, a sample cell, a measuring device for the intensities of scattered and transmitted components from a sample, a computing unit for performing processing operations based

Abstract: In a method and an apparatus for determining a content of an aliphatic hydrocarbon insoluble matter in a residual fuel oil, the method includes the steps of: (a) measuring absorbances of a sample solution having an aliphatic hydrocarbon insoluble matter suspended in the sample solution at two spaced wavelengths of light in a wavelength range from 500 nm to 1,000 nm; and (b) performing an operation to determine the content of the aliphatic hydrocarbon insoluble matter in the sample solution by inserting the measured absorbances into the specific correlations. The contents of the insoluble matter in aliphatic hydrocarbons and asphaltene in the residual fuel oil can be determined in a precise and rapid manner even if the oil contains the particles of aromatic hydrocarbons such as toluene.

Abstract: A method for determining a sludge content in a heavy hydrocarbon oil and a device therefor are disclosed. The method comprises measuring absorbances of a heavy hydrocarbon oil sample, having an oil film thickness selected form a range of form about 0.01 to 5 mm, at two different wavelengths selected from the visible light region of from 500 to 1000 nm and determining a sludge content of the sample oil by comparing two measured absorbances according to the relationship between known sludge contents and absorbances at the two wavelengths. The device comprises a light source, a cell for a sample oil, a two-wavelength absorbance detector containing two interference filters and two light-current transducers, and a computing means for converting the current values obtained into a sludge content. The method and device provide a means for rapid and precise determination of sludge contents in heavy hydrocarbon oils.

Abstract: A method for precisely and effectively determining an asphaltene content in a heavy hydrocarbon oil which can be applicable to a wider range of asphaltene content is disclosed. The method comprises measuring absorbances of a sample solution having dispersed therein asphaltene particles at two different wavelengths being at a distance of at least 50 nm selected from the visible light range of from 500 to 1,000 nm and obtaining an asphaltene content from the two measured values utilizing a relationship. A device is also disclosed for determining asphaltene content in a sample solution. It includes dipping a means for determining the absorbances at two different wavelengths into each probes which are in a line, or connecting the means into a flow cell and passing the sample solution through the flow cell to determine the absorbances.