Determination of diffusion coefficient
AssigneeOccidental Chemical Corporation
InventorsChandrasekhar Krishnan, Jian S. Qi, Joseph A. Incavo, William L. Reuter, Vivek Jain
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Abstract
Disclosed is a method of determining a diffusion coefficient for a diffusant in a particulate. An inert gas is passed through a particulate containing the diffusant. A parameter that is proportional to the concentration of the diffusant in the inert gas is measured over a period of time and the slope of the linear portion of that relationship is determined and is multiplied by a constant.
Claims20
A method of determining a diffusion coefficient for a diffusant in a particulate comprising
- (A) passing an inert gas through said particulate containing said diffusant;
- (B) measuring over time a parameter that is proportional to the concentration of said diffusant in said inert gas to produce a relationship between time and said parameter, said relationship having a linear portion and a non-linear portion;
- (C) determining the slope of said linear portion of said relationship;
- and
- (D) multiplying said slope by a constant, whereby the product is said diffusion coefficient.
A method of determining a diffusion coefficient of a diffusant in approximately spherical solid particles of approximately uniform diameter comprising
- (A) placing said particles containing a uniformly dispersed concentration of said diffusant on a gas pervious horizontal diffusor plate;
- (B) passing an inert gas up through said diffusor plate and through said particles;
- (C) measuring at at least two non-initial times a parameter proportional to the concentration of said diffusant in said inert gas;
- (D) determining the change in that parameter per unit time;
- and
- (E) multiplying said change per unit time by -R.sup.2 /.pi..sup.2, where R is the average radius of said particles and the product is said diffusion coefficient.
A method of determining the intrinsic diffusion coefficient of a diffusant in a solid spherical particulate material having an average particle size between about 10 microns and about 500 microns comprising
- (A) diffusing said diffusant into said particulate material to produce a uniform concentration of about 5 to about 40 wt % of saturation;
- (B) placing said particulate material in a fluidized bed;
- (C) fluidizing said particulate material with an inert gas;
- (D) using a gas chromatograph, measuring the rate of change of the gas chromatography area points of said diffusant in said inert gas;
- and
- (E) when said rate is constant over time, multiplying said rate by -R.sup.2 /.pi..sup.2, where R is the average radius of said particulate material and the product is said intrinsic diffusion coefficient.
Dependencies are inferred from the claim text.