We have a dp cell level transmitter for measuring of level inside a ejector with folllowing conditions: fluid is brine (liquid) and highly corrosive op temp: 50 C and design: 65 C, operating pressure: -.881 barg and design 3,5 barg, operating sp : 1.040 kg/m3, level range : 750mm. The problem is that because of corrosive fluid SS tube become defective and result in leakage and finally measuring problem. Also there is sediment inside tubing that foul tubing and a lot of maintenance is required to flush tubing periodically. Further more as you can see there is vacuum inside, and eventually we have been asked to change level measurement type with a more reliable one.
My question is with this condition that is challenging what is the best solution for it? However we came across magnetic floater level measurement with an external transmitter for continuous measurement. What about capillary dp type?
Have you considered alternative materials?
A teflon tube (to prevent build-up) inside of a hastalloy tube? Here's ABB's materials chart. Check out brine at the bottom:
I would suggest using something like an Emerson 3151S with 1199 remote seals or with electronic remote seals. This would allow you a larger port size and with a maintained continuous purge of a clean material may significantly reduce the problem. Without the purge, you will likely be required to periodically clean the port, but it would be typically a significantly longer time between clean outs than with tubing. A calibration/flushing ring should be provided. Leaking should be significantly be reduced. Also, a straight through, full port root or isolation valve should be used. Probably a Hastelloy C-276 or Tantalum diaphragm would be required but check with the vendor.
The following Emerson document lays out the various options for traditional remote seals and electronic remote seals.
If there is sufficient noise in the level signal, the transmitter may be able to detect when the plugging is getting to be significant. See the following document.
I do not have any vested interest in selling Emerson products and this is provided for example only. Other suppliers of this type of equipment may have similar products available.
William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Engineer (TUV Rheinland)
Winner of the 2018 ISA Raymond D. Molloy Award
Sr. Safety Consultant
SIS SILverstone, LLC
Is it possible that with using capillary type Hydrogen permeation occur to the cells and after a while it would become damaged? or maybe I should use gold-plated diaphragm cells to prevent Hydrogen permeation? What about magnetic float type level measurement is not it reliable and better?
In dealing with corrosion you must be quite specific in regards to the fluid.
And for example, what is the material used for the process equipment?