# Topic: Re: What is the best way to approach gas-gas mixing?

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What you want to do and what is possible may be two different things.&nbsp; Surprisingly, gas-gas mixing is relatively difficult and normally done in turbulent flow.&nbsp; Laminar gas-gas mixing, especially at low flow rates may be limited by diffusivity, rather than flow path.&nbsp; I am not sure what the dimensions are on the gas rate you have provided, so actual calculation are impractical.&nbsp; A capital "N" represents Newtons, a measure of force.&nbsp; A lower case "n" represents nano 10^-9.&nbsp; What does 1 Nm3/hr mean?&nbsp;If you can find structured packing to fit a 1/2 inch diameter pipe, you can find commercially available static mixers, especially the helical (twisted) element design.&nbsp; For laminar mixing with the twisted element design, 18 to 36 elements are recommended.&nbsp; With that guide, the mixing length needs to be 18 to 36 times the diameter, so a 36 inch long mixer should provide good mixing, whether you use static mixer elements or spherical beads.&nbsp; Better yet, reducing the tube diameter to 1/4 inch increases the velocity, turbulence and the availability of commercially available static mixers.&nbsp;Axial dispersion will increase the axial mixing and deviation from plug flow.&nbsp; Increased axial dispersion might improve mixing, but laminar flow has more of a problem with a radial gradient.&nbsp; To reduce the radial gradient, you probably need 10 or more pebbles across the pipe diameter.
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