Yes, it’s true: mixing isn’t just for liquids!
While the majority of the companies we work with use static mixers for insoluble fluids (such as water and oil), there are many instances where high performance static mixers need to be used for accelerated mixing of soluble gases. Let’s dive in, shall we?
Mixing + Sampling 101
Mixing is done to ensure a temporary homogenous mixture so that a representative sample can be taken to help measure the components that are present.
In the case of insoluble liquids (fluids that do not naturally mix, but rather separate based on their density and viscosity) mixing is very complex. There are many variables to consider in these common applications, such as the concentrations of the components, interactions of the components, finite fluid dynamics, pipe behaviour, and even the basic drop size & behaviour. These can all drastically impact mixing performance.
Once we deal with the mixing, we then need to deal with the next step: sampling. Sampling and the subsequent analysis of the samples is performed for both diagnostic and preventative purposes to ensure proper pipeline performance and compliance with any applicable regulations. The problem is that the sampling has to be done very carefully as the subsequent mixture is a very temporary state.
When sampling a mixture, it’s crucial that the sample is taken far enough away from the mixer. This is to ensure that the solution is properly mixed. At the same time, however, sampling must also be done close enough to the mixer to ensure that the components haven’t started to separate again.
When You Need to Mix Soluble Gases
We also must deal with the mixing of soluble gases, though. One specific case is hydrogen in natural gas.
With current environmental & climate trends, the injection of hydrogen in natural gas pipelines has become a very common topic. Unlike oil in water, hydrogen is soluble into natural gas, but it takes a considerably long time to do so naturally.
This poses a problem in the field: in high enough concentrations, hydrogen will result in steel embrittlement, leading to pipe damage and failure. Typically when the hydrogen is injected, it sits against the pipe wall before mixing into the flow (this can persist for many pipe diameters). Because of this, a mixing solution is necessary to properly ensure wall exposure is minimized.
Figure 1: The mixing of hydrogen into natural gas in a straight pipe with no static mixing device
A mixer will significantly cut down on the amount of exposure by accelerating this mixing; use of a high performance mixing device forces the hydrogen concentration to drop below desired target levels much more quickly.
Figure 2: The mixing of hydrogen into natural gas with a CPA Flo2Gether Static Mixer plate.
Repeatability is the Ultimate Currency
There are several reasons why mixing is essential to the proper function of many pipelines: for sampling, analysis, and piping integrity, all of which are crucial to the operation of any pipeline, and for both gases and liquids. Repeatability is critical to these operations, for measuring, mixing, and sampling.
If you’re in need of reliable mixing and flow conditioning, get in touch with us for reliable pipeline solutions!