Turbokraft Program conference 2011 COMB-1 Experimental investigation of syngas combustion at high pressure Lund University Ivan Sigfrid & Ron Whiddon

Outline Brief burner overview –Burner design notes –Test fuel parameters Lean stability limit Emissions testing –Normal operating regime: RPL variation –NOx optimization exercise Flow field visualization with PIV Flame imaging with OH pLIF DESS rig measurements –OH pLIF imaging at several pressures –Emission testing of RPL sector. Coming attractions Publication list

Burner description Three sector, concentrically arranged burner, with discrete control of respective equivalence ratios: –RPL: main burner ignition and pilot –Pilot: used to tune and stabilize RPL- main burner sectors –Main: bulk fuel delivery and oxidation

Fuels used in testing Methane is used as a generic test fuel, as it is makes up more than 90% of Natural gas. Syngas (or A2 syngas) was chosen to simulate a possible gasification product

Lean Stability Test Lower stability limit was found for each of the gases by dropping the burner’s total equivalence ratio, but holding the RPL’s static. In this manner the RPL’s role in burner stabilization is assayed.

Lean Stability Methane Methane stability limit results shown, left image is onset of instability, right image is temperature measurement on RPL body.

Lean Stability Syngas Syngas stability limit results shown, left image is onset of instability, right image is temperature measurement on RPL body.

Lean Stability Dilute Syngas Dilute Syngas stability limit results shown, left image is onset of instability, right image is temperature measurement on RPL body.

Emissions Testing NOx emissions were measured for a series of RPL equivalence ratios as the total equivalence ratio was dropped- in conjunction with the stability limit test. NOx emission was “optimized” by changing fuel partitioning to Pilot and Main sectors.

Emissions Testing 2 Left is the emissions measurement for Syngas, this behaviour characterizes each fuel tested: there is little change of NOx emission with total equivalence ratio change. However, RPL equivalence ratio has a large effect on total NOx emissions.

Emissions Testing 3 When optimizing the NOx emission by vary fuel partitioning, the Pilot was found to give correspondingly higher NOx emissions for a given equivalence ratio as compared to the Main sector. Left image is Pilot weighted fuel distribution, right is Main weighted.

Flow Field Imaging PIV Atmospheric measurement of Burner flow field in combustion and non combustion cases, also open and confined situations. Measurements with syngas proved elusive, as particles were diminished when passing through the flame. Flows were ~55 g/s total air and inlet temperatures were 650 K

PIV-Methane Combusting

OH pLIF- Methane Atmospheric Conditions for measurement were held similar to the PIV experiments done just prior: ~55 g/s total airflow 650 K inlet temperature RPL equivalence ratio 1.20 Adiabatic flame temp 1800 K Image has been corrected for laser reflections and non uniform laser energy distribution.

DESS-rig OH pLIF The RPL was run in the DESS rig while monitoring emission and recording images of the OH distribution by planar LIF. Following are average and single shot images for selected measurements. In entirety, there were: Three pressures: 3, 6 and 9 bar. Four fuels: methane, syngas, dilute methane, dilute syngas Two velocities: 1x and 1.5x velocity of atmospheric rig (60 m/s at throat)

Methane, 3 bar Single shot images, phi = Mean 500 images, phi = Intensity is from 100 to 5000 counts all pictures

A2 syngas, 3 bar Mean 500 images, phi = Single shot images, phi = Intensity is from 100 to 5000 counts all pictures

Dilute syngas, 3 bar Mean 500 images, phi = Single shot images, phi = Intensity is from 100 to 5000 counts all pictures

Methane and Syngas, 9 bar Mean 500 images, phi = Methane images, phi = Intensity is from 100 to 5000 counts all pictures Mean 500 images, phi = Syngas images, phi =

Coming Attractions Massive amounts of data have been collected, from tens of thousands of images to over a hundred thousand lines of numerical data. Thus, data processing is of utmost importance. LDA measurement of burner outlet coming May 2011 Tentative syngas transition imaging in August Full burner measurements and imaging in DESS rig, Fall 2011 Publications? –Fuel dependant flow field variation –Confinement specific flame visualization with pLIF –Elevated pressure flame visualization with pLIF –Fuel transition imaging with high speed laser excitation –...

Publication Summary Published Masters thesis Combustion Characteristics of MCV/LCV Fuels - A Numerical Chemical Kinetics Study at Gas Turbine Conditions (Daniel Jarnekrans) GT – Experimental Investigation of Laminar Flame Speeds for Medium Calorific gas with Various Amounts of Hydrogen and Carbon Monoxide Content at Gas Turbine temperature Accepted GT Experimental Investigation of Lean Stability Limit of an Prototype Syngas Burner for Low Calorific Value Gases GT Parametric Study of Emissions from Low Calorific Value Syn-gas Combustion, with Variation of Fuel Distribution, in a Prototype Three Sector Burner. ISABE 2011 – CFD Analysis of Swirl-Stabilized Burner in Gas Turbines (ABBE)