MANTRA Innovative Systems 2013

Tomorrow's Energy Solutions.
GYPSUM PLASTER KILN INVESTS IN GAS-TO-AIR HEAT PIPE HEAT EXCHANGER TO PRE-HEAT COMBUSTION AIR
This gypsum plaster kiln required a waste heat recovery system suited to operate reliably with a low temperature exhaust stream that was humid and involved a significant level of dust.





SELECTION CRITERIA
CHALLENGES
TECHNICAL DATA
Exhaust temp in: 275 F
Exhaust temp put: 198 F
Combustion air temp in: 95 F
Combustion air temp out: 187 F
Exhaust mass flow: 20,458 ACFM
Combustion air flow: 10,152 ACFM
Energy recovered: 391 kW
Payback period: 34months
SOLUTION
MANTRA proposed a finned, cross flow exhaust gas-to-air heat pipe heat exchanger built entirely in 304 stainless steel which offers many benefits in this high particulate corrosive exhaust environment. The flexibility made available by using heat pipes allowed for a completely custom-designed system and easier installation of duct work.

Other benefts of the system include high resistance to corrosion attributable to the stainless steel 304 used in manufacture and the inherent heat pipe advantage of isothermal operation which avoids cold spots and potential condensation. The installed system is also less suscepitble to fouling due to the large fin pitch pipes in staggard row configuration. The unit includes fully removable panels exposing the heat pipes in both gas chambers making the pipes easy to clean; the heat pipes can also be completely removed through the side access panel.
RESULTS
The low total combined pressure drop of 600 PA is achieved through the unique cross flow design. The return on ivnestment for this installation was 34 months.