Entrained Metal Aerosol Emissions from Air-Fired Biomass and Coal Combustion for Carbon Capture Applications

Abstract

Biomass energy with CO2 capture could achieve net negative emissions, vital for meeting carbon budgets and emission targets. However, biomass often has significant quantities of light metals/inorganics that cause issues for boiler operation and downstream processes; including deposition, corrosion, and solvent degradation. This study investigated the pilot-scale combustion of a typical biomass used for power generation (white wood) and assessed the variations in metal aerosol release compared to bituminous coal. Using inductively coupled plasma optical emission spectrometry, it was found that K aerosol levels were significantly greater for biomass than coal, on average 6.5 times, with peaks up to 10 times higher; deposition could thus be more problematic, although Na emissions were only 20% of those for coal. Transition metals were notably less prevalent in the biomass flue gas; with Fe and V release in particular much lower (3–4% of those for coal). Solvent degradation may therefore be less severe for biomass-generated flue gases. Furthermore, aerosol emissions of toxic/heavy metals (As/Cd/Hg) were absent from biomass combustion, with As/Cd also not detected in the coal flue gas. Negligible Cr aerosol concentrations were found for both. Overall, except for K, metal aerosol release from biomass combustion was considerably reduced compared to coal.

Modeling and Evaluation of Ash-Forming Element Fate and Occurrence in Woody Biomass Combustion in an Entrained-Flow Burner

“… Three-dimensional diagram of the PACT facility 250 kW combustion unit. Reprinted in part with permission from ref ( 19 ). Copyright 2018 MDPI.…”

“…The dried combustion gases then enter the plasma flame at ∼6000 K. At this temperature, any previously formed aerosols are expected to completely vaporize and will be identified in the optical detector located radially to the torch. The instrument was calibrated according to the method outlined by Finney et al 19 This was conducted with solutions at a range of concentrations for the species investigated herein. The element standards and blank solution were used to form calibration curves for each element, where the average lower detection limit was 0.041 mg/m 3 and the upper detection limit was 86.9 mg/m 3 .…”

“… Flow diagram of PACT online ICP. Reprinted in part with permission from ref ( 19 ). Copyright 2018 MDPI.…”

Advances in Biomass Co-Combustion with Fossil Fuels in the European Context: A Review

“…Finney et al (2018) [45] investigated metal aerosol emissions during biomass and coal combustion in a pilot scale combustor. Coal contained more than 3% wt.…”

“…Improved understanding of these aspects [37][38][39][40] aids the assessment of co-combustion sustainability. Greenhouse gases (GHG) emissions [41][42][43] and other emission [44,45] trends with varying biomass type and share and process conditions are studied and evaluated. New biomass and waste types are studied [46][47][48], searching for optimal co-combustion conditions, exploring material synergies [49] and improved properties and utilization of produced ash [50,51].…”