EMISSION FREE TECHNOLOGIES 1-877-342-2717

 

ASAC - ENGINEERED CONCEPTS' Answer to High Combustion Efficiency


 

asac
COMBUSTION BASICS
EXCESS AIR DECREASES COMBUSTION EFFICIENCY
PRECISELY CONTROL EXCESS AIR
ARTICLES
SCREENING QUESTIONNAIRE



Precisely Control Excess Air
The Automatic Secondary Air Control System regulates the secondary air in direct proportion to the burner fuel pressure. It uses pressure from the burner fuel manifold to operate the aircontrol valve to regulate the amount of secondary air flowing into the combustion chamber. The air control valve is adjustable to compensate for fuel composition and altitude, ensuring the correct proportion of excess air under all operating environments. Once adjusted, the ASAC maintains a constant fuel-to-air ratio across the full burner firing range by moving in response to changes in the burner fuel pressure. The system is designed to maintain the excess oxygen at 2% to 5% across the entire firing range of the burner as shown in Figure 3.
Firetube with Automatic Secondary Air Control

FIGURE 3: Stack oxygen contents comparison-ASAC vs. standard firetube
FIGURE 4: Efficiency comparison of ASAC vs. standard firetube

Eliminate Negative Heat Exchange Effects
Even when the firetube is idle, the ASAC System regulates the air flow through the firetube.This feature virtually eliminates the negative heat exchange effect associated with idle firetubes and allows use of multiple firetubes staged to accommodate the process load in the most efficient manner while still maintaining high overall combustion efficiency. Figure 4 illustrates the improved efficiency gained by controlling excess oxygen and eliminating negative heat exchange effects.
 

Application of the Automatic Secondary Air Control System is projected to save $253,162 of fuel per year and reduce carbon dioxide emissions by about 2940 tons per year.
The ASAC System is not limited to large process heating operations. Though small processes are usually more efficient than large processes, there is still room for significant savings. Even the smallest applications can attain savings of 30% or more beginning day one and continuing for the life of the unit.

ASAC (projected results based on actual field application)
  With Uncontrolled Secondary Air With Automatic Secondary Air Control System
Process heat load, MM BTU per hour 4 4
Percent excess oxygen 15.3 2.2
Stack temperature, degrees F 810 595
Combustion efficiency, percent 36 75
Fuel consumed, MM BTU per hour 11.11 5.33
Carbon dioxide emissions, tons per year 5640 2700
Cost of fuel, dollars per MM BTU 5 5
Cost of fuel, dollars per year $486,618 $233,456
Fuel and emissions reduction percentage   52

 

 

 

 

 

 

 

 

 

 

 

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Portions of the process described are covered by U.S. Patents: 5,766,313. 6,238,461. 6,364,933. 6,551,379. 6,984,257. 7,531,030 and patents pending ASAC and VRSA are patent pending.