Effect of Lean Primary-Zone Operation on Emissions and Stability of Non-Premixed Combustors

2021 ◽  
Vol 37 (1) ◽  
pp. 47-58
Author(s):  
Govindaraj Muthuselvan ◽  
Muralidhara Suryanarayana Rao ◽  
Venkat S. Iyengar ◽  
Manjunath Pulumathi ◽  
Sundararajan Thirumalachari ◽  
...  
Keyword(s):  
1989 ◽  
Vol 132 (1-2) ◽  
pp. 59-69 ◽  
Author(s):  
H.Keith McDowell
Keyword(s):  

Author(s):  
R. V. Cottington ◽  
J. P. D. Hakluytt ◽  
J. R. Tilston

A new primary zone for a gas turbine combustor has been developed which achieves efficient combustion in fuel lean conditions for minimizing carbon formation. This uses a large number of jets in the head of the chamber to generate independent shear layers in a co-operative array. Good combustion performance, wide fuel/air ratio operational range and tolerance to fuel quality have been demonstrated on research rigs. The combustor itself has been developed to an engine standard for a naval gas turbine required to operate with low smoke emission on distillate diesel fuel. The rig programme used to optimise the design is described together with results from engine evaluation. Practical advantages of this type of chamber apply equally to aero applications on kerosene.


1985 ◽  
Vol 107 (3) ◽  
pp. 739-743 ◽  
Author(s):  
J. A. Mulholland ◽  
W. S. Lanier

A 730 kW (2.5 × 106 Btu/hr) firetube package boiler was used to demonstrate the application of reburning for NOx emission control. An overall reduction of 50 percent from an uncontrolled NOx emission of 200 ppm was realized by diverting 15 percent of the total boiler load to a natural-gas-fired second stage burner. Tests indicate that the overall reaction order of destruction with respect to initial NOx is greater than one; thus, larger reductions can be expected from reburning applications to systems with higher initial NOx. Rich zone stoichiometry has been identified as the dominant process variable. Primary zone stoichiometry and rich zone residence time are parameters that can be adjusted to maximize NOx reduction. Reburning applied to firetube package boilers requires minimal facility modification. Natural gas would appear to be an ideal reburning fuel as nitrogen in the reburning fuel has been shown to inhibit NOx reduction.


Author(s):  
K. Smith ◽  
A. Fahme

The design and development testing of a full scale, low emissions, ceramic combustor for a 5500 HP industrial gas turbine are described. The combustor was developed under a joint program conducted by the U.S. DOE and Solar Turbines. The ceramic combustor is designed to replace the production Centaur 50S SoLoNOx burner which uses lean-premixed combustion to limit NOx and CO to 25 and 50 ppm, respectively. Both the ceramic and production combustors are annular in shape and employ twelve premixing, natural gas fuel injectors. The ceramic combustor design effort involved the integration of two CFCC cylinders (76.2 cm [30 in.] and 35.56 cm [14 in.] diameters) into the combustor primary zone. The ceramic combustor was evaluated at Solar in full scale test rigs and a test engine. Performance of the combustor was excellent with high combustion efficiency and extremely low NOx and CO emissions. The hot walls of the ceramic combustor played a significant role in reducing CO emissions. This suggests that liner cooling air injected through the metal production liner contributes to CO emissions by reaction quenching at the liner walls. It appears that ceramics can serve to improve combustion efficiency near the combustor lean limit which, in turn, would allow further reductions in NOx emissions. Approximately 50 hours of operation have been accumulated using the ceramic combustor. No significant deterioration in the CFCC liners has been observed. A 4000 hour field test of the combustion system is planned to begin in 1997 as a durability assessment.


Author(s):  
H. S. Alkabie ◽  
G. E. Andrews

The influence of vane angle and hence swirl number of a radial swirler on the weak extinction, combustion inefficiency and NOx emissions was investigated at lean gas turbine combustor primary zone conditions. A 140mm diameter atmospheric pressure low NOx combustor primary zone was developed with a Mach number simulation of 30% and 43% of the combustor air flow into the primary zone through a curved blade radial swirler. The range of radial swirler vane angles was 0–60 degrees and central radially outward fuel injection was used throughout with a 600K inlet temperature. For zero vane angle radially inward jets were formed that impinged and generated a strong outer recirculation. This was found to have much lower NOx characteristics compared with a 45 degree swirler at the same pressure loss. However, the lean stability and combustion efficiency in the near weak extinction region was not as good. With swirl the central recirculation zone enhanced the combustion efficiency. For all the swirl vane angles there was little difference in combustion inefficiency between the swirlers. However, the NOx emissions were reduced at the lowest swirl angles and vane angles in the range 20–30 degrees were considered to be the optimum for central injection. NOx emissions for central injection as low as 5ppm at 15% oxygen and 1 bar were demonstrated for zero swirl and 20 degree swirler vane angle. This would scale to well under 25 ppm at pressure for all current industrial gas turbines.


Author(s):  
Yunhui Peng ◽  
Quanhong Xu ◽  
Yuzhen Lin

Improvement of the lean blowout limit and more uniform combustor exit temperature distribution are particularly desirable for future aero engine. A triple swirler combination plus an airblast fuel injector might be a promising solution. The design with the triple swirler plus the airblast fuel injector including design A and B was presented and investigated in this paper. Single rectangle sector module combustor was used in the experiment for lean blowout (LBO), and three cups rectangle sector combustor was used for pattern factor (PF) experiments. The LBO and PF experiment data were provided. The primary zone flow field was measured by PIV (Particle Image Velocimetry) under atmospheric pressure and temperature. The result showed that the design A was a promising design, and the primary jet played very important role for flow field of primary zone. The insight relation between flow field and combustion performance could be found out from this paper.


Author(s):  
W P Jones ◽  
M N Sodha ◽  
J J McGuirk

Calculations have been made of the isothermal flow field within a sector of an annular combustion chamber representative of the type to be found in small gas turbines. The complex combustor geometry is described using a Cartesian finite difference mesh within which the physical domain boundaries are represented in a piecewise linear fashion. The k-s turbulence model is used to describe turbulent transport. Overall the calculated and measured flow fields are found to be in reasonable agreement and in the primary zone measured velocity profiles are reproduced to within an acceptable accuracy.


Author(s):  
Christopher D. Bolin ◽  
Abraham Engeda

Kinetic modeling of lean static stability limits of the combustion of biogas type fuels in a model of an ideal primary zone of a gas turbine combustor is presented here. In this study, CH4 is diluted with CO2 to simulate a range of gases representative of the products of anaerobic digestion of organic materials from different sources (e.g., landfill and animal waste digester). Fuels of this type are of interest for use in small gas turbines used in distributed generation applications. Predictions made by two detailed mechanisms (GRI-Mech 3.0 and San Diego) and one reduced mechanism (GRI-Mech 1.2, reduced) are employed to investigate the underlying kinetics near lean extinction. Approximate correlations to lean extinction are extracted from these results and compared to those of other fuels.


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