A device for measuring the flocculation threshold of a colloidal medium by varying the intensity of the luminous flux, and a method for measuring the flocculation threshold of a colloidal medium by the addition of aliphatic solvent using the device, including the step of determining the flocculation after the addition of the amount of aliphatic solvent necessary for flocculation.

A device for measuring the flocculation threshold of a colloidal medium, and a method for measuring the flocculation threshold of a colloidal medium by the addition of aliphatic solvent using the device, including the step of determining the flocculation after the addition of the amount of aliphatic solvent necessary for flocculation.

The impact of a stabilizing additive for treating oil-based fluids having destabilized solids, such as asphaltenes and polynuclear aromatics, may be quantitatively assessed, by determining the settling rate of flocculated destabilized solids in samples of untreated oil-based fluids and oil-based fluids treated with the stabilizing additive through the use of a turbidity meter or nephelometer while the field and quantifying the difference between the two settling rates to determine if a change in the amount of stabilizing additive applied to the oil-based fluid is necessary.

The impact of a stabilizing additive for treating oil-based fluids having destabilized solids, such as asphaltenes and polynuclear aromatics, may be quantitatively assessed, by determining the settling rate of flocculated destabilized solids in samples of untreated oil-based fluids and oil-based fluids treated with the stabilizing additive through the use of a turbidity meter or nephelometer while the field and quantifying the difference between the two settling rates to determine if a change in the amount of stabilizing additive applied to the oil-based fluid is necessary.

A method is provided for determining the solubility parameters for a process stream via the joint use of turbidimetric detection of asphaltenes flocculation, which is used to determine and detect the onset flocculation of asphaltenes of the process stream, and a refractive index to determine the process stream solubility parameters such as the solubility blending number and insolubility number.

A method is provided for determining the solubility parameters for a process stream via the joint use of turbidimetric detection of asphaltenes flocculation, which is used to determine and detect the onset flocculation of asphaltenes of the process stream, and a refractive index to determine the process stream solubility parameters such as the solubility blending number and insolubility number.

The invention relates to a method for analysing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimised. The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

The invention relates to a method for analysing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimised. The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

A method is provided for determining the solubility parameters for a process stream via the joint use of turbidimetric detection of asphaltenes flocculation, which is used to determine and detect the onset flocculation of asphaltenes of the process stream, and a refractive index to determine the process stream solubility parameters such as the solubility blending number and insolubility number.

The present invention provides a particle enhanced agglutination immunoassay including the steps of: mixing a sample solution containing an analyte with a solution containing insoluble carrier particles carrying a binding partner or binding partners for the analyte to prepare a mixed solution; determining a variation (i) in intensity of light scattered from the mixed solution based on a difference in intensity of scattered light between first and second time points; determining a variation (ii) in absorbance of the mixed solution based on a difference in absorbance between third and fourth time points; and correlating the determined variation (i) in intensity of scattered light and the determined variation (ii) in absorbance with an amount of the analyte present in the sample using a calibration curve plotted based on the variation in intensity of scattered light and a calibration curve plotted based on the variation in absorbance. The present invention employs measurements of the intensity of scattered light and the absorbance in combination for a single assay, and thus provides a particle enhanced agglutination immunoassay which achieves higher sensitivity and a wider dynamic range than conventional assays.