An Experimental Investigation of Soot Formation in Laminar Inverse and Normal Diffusion Flames at Elevated Pressure

Abstract

Hydrogen production from autothermal reforming (ATR) with Carbon Capture Utilization and Storage (CCUS) is gaining traction as prospect for a blue hydrogen economy. ATR is susceptible to catalyst poisoning and degradation from soot formation, which decrease H2 yield. In this work soot formation was examined thoroughly in conditions close to ATR, using an oxygen rich inverse diffusion flame (IDF) burner at elevated pressure. Normal diffusion flames (NDF) were also investigated against the same conditions to ultimately be compared alongside IDF. In NDF, soot formation and oxidation happen simultaneously, while in IDF soot oxidation is ignorable. Primary fuel was CO2 diluted methane, and the oxidizer stream has a 70%-by-mol O2 (30% N2) concentration. OH* chemiluminescence was used to find flame height against key parameters, PAH concentration and soot volume fraction were captured using Laser Induced Fluorescence (LIF) and Laser Induced Incandescence (LII) respectively. Key findings in this work were the dissimilarities between IDF and NDF against pressure and the effects of varying flame constituents on flame height in IDF.