Device and method for measuring diffusion coefficients of variable-volume constant-pressure gas in liquid

Abstract

The invention discloses a device and method for measuring diffusion coefficients of variable-volume constant-pressure gas in liquid. The device mainly comprises a gas sample bottle, a gas cavity, a diffusion cavity, a thermostatic bath, a valve, a vacuum pump, a reducing valve, a displacement sensor, a pressure sensor, a platinum resistance thermometer and a data acquisition system, wherein the diffusion cavity adopts a visible window structure with quartz glass; the diffusion cavity is equipped with the pressure sensor and the displacement sensor; the pressure of the diffusion cavity is kept constantly by a movable piston and a pressure-controlled gas cylinder in the diffusion process; the movement distance of the movable piston in the measurement process is measured by the displacement sensor; diffusion data of the gas in the liquid are calculated and obtained through the Fick's second law. The device realizes measurement of diffusion data of the gas in the liquid at the constant pressure, and has the advantages of simple structure, low cost, convenience in operation and stable system.

Description

technical field [0001] The invention belongs to the fields of chemical engineering and fluid thermophysical property measurement, in particular to a device and method for measuring the diffusion coefficient of gas in liquid under variable volume and constant pressure. Background technique [0002] As one of the three major migration properties of fluids, diffusion coefficient is the basic parameter for studying the movement and transfer phenomena of fluid molecules, for example, it is the limiting factor for the mixing and separation process of solutions and chemical reactions. At present, there are many reports on the measurement methods of gas diffusion coefficient in liquid, mainly including: pressure decay method, gravity balance method, time delay method, dynamic light scattering method, real-time concentration measurement method, etc. Among them, the pressure decay method is the most widely used. It mainly obtains the diffusion coefficient by measuring the relationship...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a device and method for measuring the diffusion coefficient of gas in liquid under variable volume and constant pressure, so as to solve the defect that the pressure decay method cannot measure the diffusion coefficient of gas in liquid under constant pressure

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