Moisture measurement of furnace gas

[omby]

I am looking at trying to detect water leaking from coolers around a furnace by measuring the moisture content of the gas between the metal casing of the furnace and the first layer of refractory brickwork.

Currently a combination of thermocouples and H2 monitoring is used to indicate leaking coolers but I was hoping to install something at a point where I know we always get problems to try and detect leaks earlier, or at least use it as well as the H2 and temp readings as another confirmation of a potential problem.

At the point I am looking to sample from, the furnace casing temp is around 40 degs c and is constantly sprayed with water (the coolers are further up the stack and fitted internally). The gas at this point is mainly a mix of CO and CO2 at a temp of around (I would guess) 50 to 80 degs c, and at a pressure of around 1.5 bar.

Ideally the unit will screw into a weld on socket and give a 4 to 20 mA o/p to go to our existing I/O. I am against running a sample line from the sample point to a remote instrument as this would increase the chance of leaks and create further problems.

Any comments/advice would be gratefully received.

 

[m777182]

As to measure gas humidity we have good experience with a humidity sensor type MT8636HR3 provided by Ahlborn Mess und Regelungstechnik Gmbh. It's T range is -50...+200 C and it' rh range is 0..100%. The output of it' transmitter is -500...+2000 mV for T and 0..1000mV for rh. To some extent it is protected against dust particles.You don't need to buy a digital measuring instrument (with LCD and com port), only the probe with the transmiter!Look at the web for

http://www.ahlborn.com.

m777182

 

[hacksaw]

Just use a drip pot with a level sensor. Works every time.

 

[bmsg]

See if you can install magnetic flowmeters and RTDs in the inlet and outlet water lines from the furnace.

Then, you can correct the two flowrates for the respective temperatures of the inlet and outlet water. Any difference between the inlet and outlet flow will meen a leakage.

 

[omby]

m777182 - thanks for that. I will do a bit more research about their products.

hacksaw - I think until there is a reasonably catastrophic failure of a cooler, the water lost is in vapour form.

bmsg - this is one method that is currently being looked into at present but with approx 18 rows of 32 coolers, the actual logistics of sheer numbers, finding space to actually mount the instruments, and maintaining them without mentioning the extra i/o required is somewhat prohibitive.
Obviously not all the coolers are subject to the same wear and tear, and some are more critical than others but any one of them can cause problems.

thanks for the advice so far - omby

 

[hacksaw]

omby,

the water vapor condenses in a drip pot so you always have a way to track the amount albeit on an accumulated basis rather than a instantaneous readout

hacksaw