METHOD FOR DETERMINING THE LOW-TEMPERATURE VISCOSITY OF PETROLEUM PRODUCTS, COOLING AND TECHNICAL LIQUIDS Russian patent published in 2022 - IPC G01N33/26 G01N11/00 

FIELD: testing equipment.

SUBSTANCE: invention relates to the technology of testing petroleum products and can be used for determining the viscosity of petroleum products, cooling and technical liquids at low temperatures. The invention concerns a method for determining the low-temperature viscosity of petroleum products, cooling and technical liquids, including a preliminary series of measurements to determine the viscosity with a gradual decrease in temperature, plotting the dependence graph of viscosity on temperature, determining the low-temperature viscosity of a liquid at ambient temperature. A dependence graph of viscosity on temperature is constructed for a standard liquid with stability of temperature-viscosity characteristics in the temperature range from minus 40°C to 100°C, the resulting graph is divided into five sections, each section is smoothed by the least squares method for experimentally obtained values of kinematic viscosity by second degree polynomials with regression coefficients 0.999-1.0, according to the approximating curve equations, the exact temperature values are determined for these temperature intervals, under which the standard liquid has viscosity of the studied samples T_1,ST, T_2,ST, the ΔT_ST: ΔT_ST=T_1,ST-T_2,ST value is calculated, ΔT for the test fluid is calculated: ΔT=T_1,l-T_2,l, and the k-factor: k=ΔT/ΔT_{ST is} calculated, the value of the temperature is calculated at which the viscosity of the standard liquid is equal to the viscosity of the test liquid at the selected temperature: T_0,ST=[(T_0,l-T_1,l)+k⋅T_1,ST]/k, the temperature range of the temperature-viscosity curve of the standard liquid is determined, in which the calculated value T_0,ST is located, and the desired viscosity value of the liquid under study is calculated using the equation of the approximating curve for this interval.

EFFECT: reduction in the implementation time of the method, simplification and expansion of the viscosity range of the method for determining the low-temperature viscosity of petroleum products, cooling and technical liquids.

3 cl, 1 tbl, 6 ex, 5 dwg