Stack Test Specialists

Hex Chrome in a Hot Stack

March 23rd, 2008 Posted in Methods

The first few sentences of SW846-0061 states the test should not be conducted in stacks 300F or greater.  I recently completed three good runs in a stack averaging about 330F.  The Teflon components held up to the temperatures, although they did become a bit soft.  It seems Teflon will grow and create a good seal in the stack, but shrinks rapidly when coming back to ambient temperatures.  I found it necessary to leak check the train immediately after taking it out of the stack.  I also used a shorter probe to utilize all four ports, which minimized the amount the time the train sat in the stack.  The probe was also an oversheath gland-fitting type probe which I felt kept the probe liner cooler.  The recirc line to the aspirator union was seemed to hold up well.  I did switch off the recirculation pump about 20-30 seconds prior to the completion of each port.  This was to give the potassium hydroxide solution a chance to be sucked down by the sampling train so it was not lost through the tip of the nozzle during the port change.  I was dealing with a relatively high velocity stack which called for a small (.182″) nozzle and a higher draw rate. (average delta H around 1.5″H2O)  We are still awaiting the stack test results.  I will update the post accordingly.

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  2. May 4, 2010: Kylie Batt
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