JOHN LETCAVITS
Engineers in Hilliard, OH

6659026, Dec 9, 2003

Jan 30, 2002

10/060587

Willis M. Hendricks - Gahanna OH
John J. Letcavits - Hilliard OH

AEP EmTech LLC - Columbus OH

F23D 100

110347, 110186, 110261, 431 12

A control system for providing improved control over the combustion process of a multiple-intertube pulverized-coal burner that commonly forms a portion of a roof-fired boiler. The system utilizes actual mass fuel flow measurements to calculate corrected, optimal secondary and interjectory air demands. The corrected secondary and interjectory air demands are used by a proportional and integral control loop to regulate the respective supply of secondary and interjectory air to the combustion process of each in-service burner. The control system allows for optimal combustion of the fuel and a reduction in NO emmissions.

5960723, Oct 5, 1999

Jan 29, 1998

9/015836

Scott A. Vierstra - Canal Winchester OH
John J. Letcavits - Hilliard OH

AEP Resources Service Company - Columbus OH

F23J 1500, F23B 502

110297

A method and apparatus retrofitted to a multiple-intertube pulverized-coal burner to reduce NO. sub. x emissions of roof fired boilers. An internal two stage process controls the amount of secondary air which flows to the burner. The first stage includes a secondary air damper and air flow station to regulate the amount of air which flows into a windbox of the burner. A baffle plate assembly which includes a plurality of baffle plates further limits the amount of air which flows to the core of the burner for combustion of the fuel. The baffle plates create a pressure drop within the windbox which forces or diverts a quantity of air to the periphery of the burner. The second stage includes an outlet formed in the hot primary air duct, an air plenum which communicates therewith, and a plurality of interjectory air ports which correspond with the burners in number and position along a front wall of the boiler and which communicate with the air plenum. The interjectory air ports inject interjectory air into a combustion chamber of the boiler at a substantially 90 degree angle to the direction of a plurality of burner tips of each burner and supplies the balance of the required theoretical combustion air needed to complete combustion of the fuel. A plurality of probes measure the amount of primary air, secondary air and interjectory air and signal a command loop circuit to adjust the secondary air dampers and interjectory air ports accordingly.

5771823, Jun 30, 1998

Jan 31, 1996

8/594855

Scott A. Vierstra - Canal Winchester OH
John J. Letcavits - Hilliard OH

AEP Resources Service Company - Columbus OH

F23D 100, F23J 300

110347

A method and apparatus retrofitted to a multiple-intertube pulverized-coal burner to reduce NO. sub. x emissions of roof fired boilers. An internal two stage process controls the amount of secondary air which flows to the burner. The first stage includes a secondary air damper and air flow station to regulate the amount of air which flows into a windbox of the burner. A baffle plate assembly which includes a plurality of baffle plates further limits the amount of air which flows to the core of the burner for combustion of the fuel. The baffle plates create a pressure drop within the windbox which forces or diverts a quantity of air to the periphery of the burner. The second stage includes an outlet formed in the hot primary air duct, an air plenum which communicates therewith, and a plurality of interjectory air ports which correspond with the burners in number and position along a front wall of the boiler and which communicate with the air plenum. The interjectory air ports inject interjectory air into a combustion chamber of the boiler at a substantially 90 degree angle to the direction of a plurality of burner tips of each burner and supplies the balance of the required theoretical combustion air needed to complete combustion of the fuel. A plurality of probes measure the amount of primary air, secondary air and interjectory air and signal a command loop circuit to adjust the secondary air dampers and interjectory air ports accordingly.

6155183, Dec 5, 2000

Jul 21, 1999

9/358301

Scott A. Vierstra - Canal Winchester OH
John J. Letcavits - Hilliard OH

A E P Resources Service Company - Columbus OH

F23B 502, F23B 700, F23N 518

110345

A method and apparatus retrofitted to a multiple-intertube pulverized-coal burner to reduce NO. sub. x emissions of roof fired boilers. An internal two stage process controls the amount of secondary air which flows to the burner. The first stage includes a secondary air damper and air flow station to regulate the amount of air which flows into a windbox of the burner. The second stage includes an outlet formed in the hot primary air duct, an air plenum which communicates therewith, and a plurality of interjectory air ports which correspond with the burners in number and position along a front wall of the boiler and which communicate with the air plenum. The interjectory air ports inject interjectory air into a combustion chamber of the boiler at a substantially 90 degree angle to the direction of a plurality of burner tips of each burner and supplies the balance of the required theoretical combustion air needed to complete combustion of the fuel. A plurality of probes measure the amount of primary air, secondary air and interjectory air and signal a command loop circuit to adjust the secondary air dampers and interjectory air ports accordingly. The burner tips extend into the central core of each windbox and mixes with the incoming secondary air to provide for the fuel rich mixture.