Waste Heat Generates Steam, Saving $216,000 a Year

Problem

A coil coating facility purchased a new a 15,000 SCFM Regenerative Thermal Oxidizer (RTO) which has a nominal heat transfer efficiency rate of 90% and designed with supplemental fuel injection (SFI) which is used during low VOC loading conditions, to help save fuel cost.  The facility was looking at ways to decrease their exhaust air temperature. 

Action

The high exhaust temperature (above 650°F) and large airflow (12,650 SCFM) in the oxidizer exhaust stack provided the customer an opportunity to add energy recovery measures to further optimize their process and  decrease their operating costs.  .  It was that their process required a significant amount of steam and would likely provide the quickest payback for an energy recovery project. 

Solution

Anguil Environmental Systems Inc. installed an Air to Steam; Waste Heat Recovery Boiler to recover exhaust waste heat from a natural gas fired regenerative thermal oxidizer and produce 25 psig steam.  The boilers use X-ID tubing for enhanced heat transfer through the helical ribs on the inside of the tubes.  

The Waste Heat Boiler package is a skid-mounted unit, forced circulation, fire tube, and heat recovery steam generator. The unit has automatic, modulating, exhaust gas bypass that is controlled by steam pressure.  A boiler feedwater and blowdown separator was included as part of the package.   

Installing the waste heat boiler system recovered about 2.58 MM BTU/hr of energy, lowering the  stack temperature  to 338°F. The addition of the waste heat boiler on this application saved the facility $216,770 per year.  The total payback period for this project was less than six (6) months. 

 Reported Values

PROJECTED VALUES WITH ENERGY RECOVERY SYSTEM

Job Pictures