High Temperature Consistency Measurement

[j_p_c]

Hi Folks,

Thanks in advance for your time in reading this. First time poster to this group. As a forewarning, I've spent more time on the Power T&D group, so please show mercy

I'm supporting a process upgrade that requires consistency measurement of hot water with some residual pulp (water side outlet of a steam scrubber). The fluid is quite hot with two options for measurement location either at 139C or 167C. The plan up to now had been to install an optical unit.

I'm finding that none of the major vendors surveyed so far offer consistency measurement for process fluid temperatures above 120C. (Valmet, BTG; awaiting responses from Voith and ABB). In general, Microwave seems to be even more limited, generally at 100C.

Has any one on this forum dealt with this limitation before, either having found a suitably rated product, or went into the engineering enough to challenge/accept the risk to the optical (or other) interface? Finally, I haven't yet looked into inferring consistency via mass-flow or other, that's the next step but any input is highly welcome!

Thanks much,
Justin

 

[Compositepro]

In this case does consistency mean viscosity?

 

[hacksaw]

There are all sorts measurements but you have to be specific.

 

[thebard3]

The temperatures you cite should not be considered as high temperature for most process measurement instrumentation. I don't know of a typical engineering unit for 'consistency'. I assume, like Compositepro suggests, that you are interested in viscosity, or perhaps % solids or maybe other parameter for measurement. There are a number of ways to measure either.

Brad Waybright

It's all okay as long as it's okay.

 

[j_p_c]

Thanks For The Feedback!

Consistency means oven dry weight of pulp. We may just do manual sampling given the difficulties. Microwave is an option, but depends on conductivity and entrapped air, still following that up. Radiometry can't sense below 2% consistency, and optical might work but would require a cooled bypass line that might be subject to plugging, and of course added cost.

Thanks and have a great day!

Justin

 

[Compositepro]

% solids can be measured very accurately by density using a number of techniques, like vibrating tubes. Air can be eliminated by doing the measurement under pressure or by vacuum degassing before measurement.

 

[j_p_c]

Thanks Compositepro!