Optimizing Heat Exhaust Capture for Natural Gas Fired Industrial Heaters

[Jake Platt]

Given a natural gas fired industrial heater dryer which gives off 70,000 CFM of 190F air at 1.1 atm air pressure, is it practicably possible to capture 24 hours worth of this heated air exhaust into a compressed storage tank?

How would I calculate the theoretical maximum compression ratios and tank volume requirements?

 

[Mech_Engineer]

Given a natural gas fired industrial heater dryer which gives off 70,000 CFM of 190F air at 1.1 atm air pressure, is it practicably possible to capture 24 hours worth of this heated air exhaust into a compressed storage tank?

How would I calculate the theoretical maximum compression ratios and tank volume requirements?

There's no way you could store that kind of volume in a single tank, and doing so would be a losing proposition anyway. http://www.wolframalpha.com/input/?i=70000+cfm+*+24+hours".

I'm getting the feeling you're actually interested in capturing/utilizing/storing the energy in the exhaust from the dryer, which could possibly be done with some sort of http://en.wikipedia.org/wiki/Brayton_cycle" , which assuming atmospheric temperature is 75 F will be 17.5% (but if it's "free" energy, who cares? Run a generator and pipe that energy back into the dryer...)

 

[Jake Platt]

Thank you. Actually, our goal is ultimately to filter the air to remove suspended Nox or VOC particulate matter but the air filtration system cannot handle 70,000 CFM so we were considering compressing and storing the air so we can filter it later at a metered, controlled rate. But alas, it seems that won't work either. Any ideas??

 

[Mech_Engineer]

Get a filtering system that can keep up with the flow rate, or look into additives or secondary processes that reduce NOx?

 

[AlephZero]

If you are getting enough pollutants to need filtering, that suggests there is something wrong with your gas burners, or you are using low quality gas.

In any case, the pollutants have presumably already contaminated whatever you are drying before you would filter them from the exhaust.

 

[Jake Platt]

The natural gas combustion is what creates the NOx. We are talking about environmental pollution control not decontamination of a polluted process. The process starts with clean agricultural commodities at 80% moisture and ends with the commodities at 10% moisture and voluminous quantities of heat exhaust from the natgas combustion that has suspended VOC's and NOx emmissions.