tech details

Real-Time Combustion Control and Diagnostics Sensor-Pressure Oscillation Monitor

Opportunity

The Department of Energy’s National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implementing its patented "Real-Time Combustion Control and Diagnostics Sensor-Pressure Oscillation Monitor" technology.

Disclosed is NETL’s sensor system and process for monitoring and controlling the amplitude and/or frequencies of dynamic pressure oscillations in combustion systems during active combustion processes. The combustion control and diagnostics sensor (CCADS) is designed for gas turbine combustors that are operated near the fuel-lean flame extinction limit to minimize production of the atmospheric pollutant NOx. CCADS eliminates the problems of flashback, lean blowoff, and dynamic pressure operations sometimes experienced at these conditions.


Overview

Pressure oscillations in a combustor can result in variations in both the amplitudes and frequencies in the combustion chamber, possibly resulting in adverse consequences. Detecting and controlling the pressure oscillation is of critical importance.

This patented work at NETL has focused on using a flame to detect and measure combustion instabilities. CCADS uses the electrical properties of a flame to detect key events and monitor critical operating parameters within the combustor. The oscillating flame produces hydrocarbon ions and electrons, inducing current to flow in an electrode that is part of the circuit. The electrode is calibrated to monitor the dynamic pressure oscillations in the combustion chamber by applying a constant voltage between the electrode and ground, resulting in a current in the electrode. By varying one or more of (1) the flow rate of the fuel, (2) the flow rate of the oxidant, (3) the equivalence ratio, (4) the acoustic tuning of the combustion system, and (5) the fuel distribution in the combustion chamber, the amplitudes of the dynamic pressure oscillations in the combustion chamber can be calculated as a function of the electrode current.

When incorporated as part of a control circuit in the combustor system, CCADS can vary the fuel flow rate, the oxidant flow rate, the ratio of fuel to oxidant, the distribution of fuel in the combustion chamber, or a combination of these four parameters to reduce the amplitudes of the dynamic pressure oscillations in the combustion chamber. In experiments, a CCADS has been used as part of a highly instrumented atmospheric combustor to measure the pressure oscillations in the combustor, the OH emission, and the flame ion field at the premix injector outlet and along the walls of the combustor.


Significance

This technology provides:

  • A method of monitoring potentially damaging dynamic pressure oscillations in a gas turbine combustor
  • A method of reducing the amplitudes of the dynamic pressure oscillations during combustion
  • A means of operating a gas turbine combustor near the fuel-lean flame extinction limit to minimize NOx formation


Related Patents

U.S. Patent No. 7,559,234, titled "Real-Time Combustion Control and Diagnostics Sensor-Pressure Oscillation Monitor," issued July 14, 2009.

Inventors: Benjamin Chorpening, Jimmy Thornton, E. David Huckaby, George Richards

U.S. Patent No. 7,927,095, titled "Time Varying Combustion Control and Diagnostics Sensor" issued April 19, 2011.

Inventors: Benjamin Chorpening, Jimmy Thornton, E. David Huckaby, George Richards


For more information Contact Us