Energy Recovery Air-to-Water

HEATING PROCESS WATER WITH OXIDIZER EXHAUST:

9 MONTH PAYBACK and ENVIRONMENTALLY GREEN.

Controlled Environment's latest Energy Recovery Project involves recovery of exhaust from a Regenerative Oxidizer with a temperature of 250⁰F using an air-to-water energy recovery system.

Several years ago this customer purchased a regenerative oxidizer form Controlled Environment to control VOC emissions from their coating process. The quantity of VOC’s in the airstream is sufficient to allow the oxidizer to be self-sustained (it did not need auxiliary fuel to operate.) The final exhaust from the oxidizer is 250⁰ F and the unit is rated at 35,000 scfm. As natural gas prices started to increase in cost our customer called us in and asked if there was any way they could save energy and reduce their fuel bills.Controlled Environment did an engineering study and determined that the customer used large quantities of hot water for several washing processes in production.

The process is wash water of 130 gallons per minute being heated from 70⁰F to 140⁰F. The system that we designed used one water coil in an enclosure at the stack of the oxidizer with dampers to direct the airflow through the coil and control the heat being recovered. The system as engineered, recovered enough energy to meet the requirements: heating 130gpm from 70F to 140F with out adding any additional fuel. This saved the customer 4,550,000 btu's/hour and they operate 8700 hours per year which saved the customer $450,000 per year at $1.10 per therm of natural gas. The payback for this system is 9 months. In addition, since the existing burners for heating the water were no longer needed, this energy recovery system reduced their CO2 production by 4,698,000 pounds per year. Needless to say, the customer is quite pleased with their return on investment and the system is Environmentally Green.

Article by:

David Swinehart,

VP of Engineering

Controlled Environment