Lightning arrester exposed to hot gas

[Histor]

Can we keep a lightning Rod closer to Hot gas (Approx. 1100deg. C) exposure? Please note that the Lightning rod material is Copper.

 

[FacEngrPE]

Copper is typically "annealed" in the temperature range of 700-1200ºF. If your terminal is actually in the hot gas stream, it will get rather soft, and erode, but for the purpose of a lightning air terminal, will not adversely affect it's function.
If this is part of a industrial chimney, all of the lightning system should be inspected when the chimney (or stack) is inspected. Typically every 5 years, I would not be surprised if you need to replace lightning terminals exposed to 1100F every 5 years.

 

[RRaghunath]

You mean a gas at 1100degC is being let out in to atmosphere on a continuous basis in your plant? Is it not a waste of so much energy/money?
Are you sure the plant doesn't have any waste heat recovery arrangement?
Is this allowed environmentally??
I am familiar with Lightning rods on top of Chimneys in power plants. But, the gas is at much lower temperature (about 100degC I suppose, if my memory is serving me right) having passed through Economiser and Air Pre heater.

 

[FacEngrPE]

Most power plants boilers attempt to exhaust stack gas a bit above the condensation temperature. Lower than this and significant additional cost is incurred as corrosion resistant material.
For coal and 2.5% sulfur heavy oil, and no emissions scrubbing this works out to about 450F to 550F. For natural gas and low sulfur oil perhaps 250F.

https://www.babcockpower.com/wp-content/uploads/2018/02/emissions-of-sulfur-trioxide-from-coal-fired-power-plants.pdf[/URL]]

 

[cranky108]

I could see 1100C for a peaking power plant, but you would not want to run that all the time, as the cost of fuel vs a combined cycle plant.

Then again, a peaking plant stack is not that tall.

 

[7anoter4]

NFPA 780 requirement:
6.2.2 Corrosion Protection. Copper and bronze materials
used on the upper 7.6 m (25 ft) of a stack shall have a continuous
covering of lead having minimum thickness of 1.6 mm
(1⁄16 in.) to resist corrosion by flue gases
6.3.5.1 An electrically continuous steel hood covering the
stack lining and column, having a metal thickness of not less
than 4.8 mm (3⁄16 in.), shall be permitted to serve as the strike
termination device.
However, if the hood it is of stainless steel made the maximum continuously applied temperature it has to be not more than 450 oC.
You may try the NASA copper alloy GRCop-84: A High-Temperature Copper Alloy for High-Heat-Flux Applications. This material withstands maximum 800oC.