23 posts

### rawmix homo silo efficiency

Dears,

Upon calculating the Homo factor (H) of raw mix blending silo, H = 1.2

is it within typical range? what is typical range (benchmark, guideline...)?

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138 posts

### Re: rawmix homo silo efficiency

I am not a specialist of blending silos.

However, my guess would be that reducing the standard deviation by only 20% means that there is NO useful homogenisation.

I would expect rather a factor 5 or 10 reduction in the deviation to really talk about an homogeneisation effect.

Of course, it depends on your actual needs.

But it is hard for me to see why you would pay to reduce the fluctuations by only 20% .

536 posts

### Re: rawmix homo silo efficiency

Hello Emad,

I agree with Lalbatros. The FLS homogenising factor H is given by;-

H =
Ö ((S_{in}^{2
}- S_{an}^{2}) /
(S_{out}^{2
}- S_{an}^{2}))

where;

S_{in
}= The standard deviation of one chemical parameter in the feed to the silo.

S_{out
}= The standard deviation of the same chemical parameter in the discharge from the silo.

S_{an
}= The standard deviation attributable to analysis errors.

(The IBAU calculation is slightly different but essentially the same principle.)

Generally, H values should be >5 if the degree of homogenisation is to be considered really efficient. So I am sorry to say that a value of 1.2 is almost no blending at all.

However, this does not necessarily mean that there is a problem with the variability of the kiln feed. In the special case where the chemical variability of the raw meal being fed into the homogenising silo is already very low and the same as that of the kiln feed exiting the silo then the H value will be 1. This is why it is best to test the efficiency of a homogenising silo by making sure that there is sufficient variability in the incoming raw meal.

Regards,

Ted.

67 posts