A method for recalculating the solvent power of a light oil, SP.sub.(LO recalculated), is provided. The method comprises: titrating the light oil against a reference oil, optionally in the presence of a titrant, to determine a volume fraction of the light oil at the onset of asphaltene precipitation, V.sub.(onset fraction LO), a volume fraction of the reference oil at the onset of asphaltene precipitation, V.sub.(onset fraction RO), and, where a titrant is present, a volume fraction of the titrant at the onset of asphaltene precipitation, V.sub.(onset fraction T), and determining the recalculated solvent power of the light oil, SP.sub.(LO recalculated), according to the following formula:

[00001]${\mathrm{SP}}_{\left(\mathrm{LO}.Math..Math.\mathrm{recalculated}\right)}=\frac{\left({\mathrm{CSP}}_{\left(\mathrm{RO}\right)}-{\mathrm{SP}}_{\left(\mathrm{RO}\right)}*V_{\left(\mathrm{onset}.Math..Math.\mathrm{fraction}.Math..Math.\mathrm{RO}\right)}-x*{\mathrm{SP}}_{\left(T\right)}*V_{\left(\mathrm{onset}.Math..Math.\mathrm{fraction}.Math..Math.T\right)}\right)}{V_{\left(\mathrm{onset}.Math..Math.\mathrm{fraction}.Math..Math.\mathrm{LO}\right)}}$

wherein: CSP.sub.(RO) is the critical solvent power of the reference oil, SP.sub.(RO) is the solvent power of the reference oil, SP.sub.(T) is the solvent power of the titrant, and x is 1 where a titrant is present, and otherwise is 0.

The recalculated solvent power may be used in methods for preventing asphaltene precipitation during processing of crude oils in a refinery.

The present disclosure relates to methods of monitoring the concentrations of silver ion and complexing agent in tin-silver (SnAg) electrodeposition solutions, and analysis and process control using such methods. Methods can include adding a precipitating agent to an electrodeposition solution including at least tin ions, silver ions, and complexing agent to cause a reaction between at least a portion of the precipitating agent and substantially all of the silver ions (to precipitate silver ions as a precipitant); adding a metallic salt to the electrodeposition solution to cause a reaction with substantially all of the remaining precipitating agent; measuring the endpoint of the silver ion back titration; further adding metallic salt to cause a further reaction with the complexing agent; and measuring the endpoint of the complexing agent titration.

Provided herein are cellulose acetate tow bands having less than 0.1 wt. % titanium dioxide, wherein the content of titanium dioxide is measured by ashing and/or by titanium particle count density. Also provided herein is a method of measuring the titanium dioxide content of cellulose acetate tow by ashing. Also provided herein is a method for measuring the color of cellulose acetate tow.

Provided herein are cellulose acetate tow bands having less than 0.1 wt. % titanium dioxide, wherein the content of titanium dioxide is measured by ashing and/or by titanium particle count density. Also provided herein is a method of measuring the titanium dioxide content of cellulose acetate tow by ashing. Also provided herein is a method for measuring the color of cellulose acetate tow.

The present invention is a method for estimating a physical property of an aqueous sample containing a surfactant and water, comprising: adding an oil component and a phase-changing probe to the aqueous sample, and estimating the physical property of the aqueous sample from an amount of the phase-changing probe when a phase structure of the mixture changes.

Embodiments provide a method for determining a chloride content of an alumina-based catalyst used for catalytic reforming. The method includes the step of combining nitric acid, isopropanol, and the alumina-based catalyst such that the alumina-based catalyst is dissolved in the nitric acid and the isopropanol to form a homogenized mixture. The alumina-based catalyst include chloride. The method includes the step of taking a conductivity measurement of the homogenized mixture using a pair of electrodes. The method includes the step of introducing a titrant solution comprising silver nitrate to the homogenized mixture such that a precipitate of silver chloride is formed. The method includes the step of determining a chloride concentration of the homogenized mixture based on the conductivity measurement of the homogenized mixture. The method includes the step of determining the chloride content of the alumina-based catalyst based on the chloride concentration of the homogenized mixture.

Embodiments provide a method for determining a chloride content of an alumina-based catalyst used for catalytic reforming. The method includes the step of combining nitric acid, isopropanol, and the alumina-based catalyst such that the alumina-based catalyst is dissolved in the nitric acid and the isopropanol to form a homogenized mixture. The alumina-based catalyst include chloride. The method includes the step of taking a conductivity measurement of the homogenized mixture using a pair of electrodes. The method includes the step of introducing a titrant solution comprising silver nitrate to the homogenized mixture such that a precipitate of silver chloride is formed. The method includes the step of determining a chloride concentration of the homogenized mixture based on the conductivity measurement of the homogenized mixture. The method includes the step of determining the chloride content of the alumina-based catalyst based on the chloride concentration of the homogenized mixture.

The present disclosure relates to a measuring cell for carrying out chemical analyses, having a vessel, in which at least one liquid to be analyzed is located; a heating wire, which is guided at least partially around an outer wall of the vessel, so that the liquid inside the vessel can be heated in a uniform and controlled manner; and a first temperature sensor, which determines and/or monitors a first temperature of the liquid. The measuring cell furthermore comprises a magnetic stirrer with a stir bar and a cover for closing the vessel, wherein the cover has a plurality of ducts, wherein at least one first duct is provided for at least one first analysis sensor, which determines and/or monitors at least one chemical and/or physical variable of the liquid of the vessel and wherein at least one second duct is provided for a liquid line.

The present disclosure relates to a measuring cell for carrying out chemical analyses, having a vessel, in which at least one liquid to be analyzed is located; a heating wire, which is guided at least partially around an outer wall of the vessel, so that the liquid inside the vessel can be heated in a uniform and controlled manner; and a first temperature sensor, which determines and/or monitors a first temperature of the liquid. The measuring cell furthermore comprises a magnetic stirrer with a stir bar and a cover for closing the vessel, wherein the cover has a plurality of ducts, wherein at least one first duct is provided for at least one first analysis sensor, which determines and/or monitors at least one chemical and/or physical variable of the liquid of the vessel and wherein at least one second duct is provided for a liquid line.

The disclosure discloses cerium sulfate chelated sulfur dioxide, a preparation method and a use thereof. The cerium sulfate chelated sulfur dioxide has a molecular formula of Ce[SO4][SO2].2H2O. It is a white crystal and the preparation method thereof may comprise the following steps: adding anhydrous cerium sulfate to dilute sulfuric acid with stirring for dissolvation; adding a solvent followed by refluxing at 45-50 C. for 2.0-2.5 h; heating the reaction product to remove the solvent, cooling to 20 C. or lower, and adding dilute sulfuric acid to allow precipitation of all crystals; cooling down the product followed by suction filtration, washing the obtained crystals by the solvent, so that crude cerium sulfate chelated sulfur dioxide can be obtained. The solubility of the cerium sulfate chelated sulfur dioxide of the disclosure has been significantly improved compared to the anhydrous cerium sulfate. The obtained solution is colorless and transparent, so that the cerium sulfate chelated sulfur dioxide can be used as a better titrant with wide application and supreme performance.