One-Dimensional Predictive Emission Monitoring Model for Gas Turbine Combustors

Abstract

Current predictive emission monitoring (PEM) techniques are briefly reviewed and the concept for a general predictive model was favorably evaluated. Utilizing the commercial process simulation software ASPEN PLUS®, a one dimensional model based on fundamental principles of gas turbine thermodynamics and combustion processes was constructed. Employing a set of 22 reactions including the Zeldovich mechanism, the model predicted for thermal NOx formation. It accounted for combustor geometry, dilution air injection along the combustor annulus, convective heat transfer across the liner, flame length, and full-load inlet flows. The combustor was subdivided into slices, each of which was modeled by a plug flow reactor, giving insight into profiles of NOx formation, species concentration and temperature along the combustor’s length, as well as quantifying the residence time in the combustor. The simulation predicted the levels of NOx for a particular gas turbine combustor and determined the effects of various parameters, such as flame length, hydrocarbon conversion ratio and recycle zones.

Thermodynamic, Environmental and Economic Assessment of Exhaust Gas Recirculation for NOx Reduction in Gas Turbine Based Compressor Station

“…A group of five reactions were added to the Zeldovich reactions to account for the production and presence of N, 0, H and OH in the combustion chamber. The kinetic constants of these reactions and the Zeldovich reactions are given in [8]. Addition of other possible reactions did not improve the accuracy of NO, prediction [8].…”

“…In general, the main factors controlling NO, emissions from conventional combustors are the homogeneity of the combustion process, temperature, equivalence ratio, the residence time in the primary-zone, and the liner-wall quenching characteristics. There are some Predictive Emission Monitoring (PEM) models that incorporate all of these parameters, or, equivalently, utilize fundamental combustion mechanisms, and can be applied to any given machine [7,8]. In the present study, a one-dimensional model previously developed for PEM [8] is utilized to thermodynamically assess and quantify NO, reduction through EGR in a typical stationary natural gas fueled turbine system.…”

“…There are some Predictive Emission Monitoring (PEM) models that incorporate all of these parameters, or, equivalently, utilize fundamental combustion mechanisms, and can be applied to any given machine [7,8]. In the present study, a one-dimensional model previously developed for PEM [8] is utilized to thermodynamically assess and quantify NO, reduction through EGR in a typical stationary natural gas fueled turbine system. The fuel gas composition is given in Table 1.…”

“…The kinetic constants of these reactions and the Zeldovich reactions are given in [8]. Addition of other possible reactions did not improve the accuracy of NO, prediction [8]. Preliminary results of the developed EGR model were presented in [9].…”

One-Dimensional Model to Quantify NOx Reduction in Gas Turbines Using EGR

“…is becoming more mature [1-4] and accepted by regulatory bodies, the tools used therein also provide means for assessing both older and newer techniques for NO X reduction. This paper uses a previously developed onedimensional PEM model [5] to assess and quantify NOX reduction in gas turbines by the exhaust gas recirculation (EGR) technique.…”