Flow Measurement Inside Cement Duct

Non-invasive types such as clamp-on ultrasonics spring to mind.

Ultrasonics is a good idea.

Please keep us informed as to what you choose and how it works out.

Many ultrasonics require minimum gas pressures to get the density high enough to function get sufficient signal strength through the gas medium.

Dust probably eliminates transit time ultrasonic, leaving doppler. It isn't clear to me how well doppler pings through cement, nor its suitability for low pressure gas.

Doppler shift takes place only due to velocity. Particulate matter and voids cause reflections for ultrasonic wavefront. Ultrasonics is frequently used for velocity measurement in thick concrete. I think that is not a serious matter. One can select proper frequency for ultrasonic probe for density, size of the duct etc. Temperature variations may be of concern as Ultrasonic velocity changes with temperature. Temperature measurement and reading correction is essential.

What is the pressure, temperature and expected flow rate, size of the duct and the wall thickness? What is the gas composition?

Hello, I am unaware of Cement processes. would you mind sharing the medium which you want to measure i.e. Liquid, gas, steam or abrasive? for flow and heat measurement Thermal and Vortex with thermal option is best. Ultrasonic wont meaure heat BTU/hr etc.

Vortex (with thermal sensor) is a safer choice as it is compatible with higher temperatures and pressures. Hope it would help.

I've worked on a cement plant as electrical engineer. I recall ball mills for raw materials, ball mills for coal pulverisation, a long cylindrical rotary furnace converting the raw materials to clinker, more ball mills & fans converting clinker into cement powder and bag filters to catch the stuff.

Are you trying to recover the heat at the end of the long rotary furnace where the raw materials go in and clinker comes out? What are you trying to control by measuring flow, and temperature if you need to know the heat available?

Thanks for many comments. Here is what I am trying to do with measuring flow in the cement duct.

First of all, I am thinking of installing waste heat recovery boiler between PH and ID fan, and between AQC and EP to generate power. It looks like below.

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I wish to continuously measure the flow in the duct to check boiler performance and for some other reasons.

There are several kilns which I would like to install above system, so Waste gas composition varies according to the kiln, but it is like N2(78%), O2(3%), CO2(15%), H20(4%) and dust contents is over 50 (g/Nm3).

The gas pressure and temperature after PH and AQC also varies, but it is like 700 mmAq and 400 °C after PH and -100 mmAq and 420 °C right after AQC.

Thanks.

-700 mmAq right after PH boiler(due to ID fan) is correct.