Impact of Boiler Type, Heat Output, and Combusted Fuel on Emission Factors for Gaseous and Particulate Pollutants

Abstract

Five different boiler types (automatic boiler, overfire boiler, boiler with down-draft combustion, and two types of gasification boilers) representing residential-scale combustion technology were tested. Boilers were fueled with various fuels (lignite, wet and dry wood, wood pellets, and mixed fuel), and the combustion emissions were measured both at nominal and reduced output. The investigated emissions comprised CO, organic gaseous compounds (OGC), and particulate matter (PM). A cyclone and a low-pressure impactor were used to determine PM emissions. It was found that the emission factors for CO, OGC, and PM depend more on boiler type and mode of operation (reduced or nominal output) than on fuel type. Data from the Dekati low-pressure impactor (DLPI) show that, in most cases, PM1 represents approximately 80% of the total PM mass. PM0.1 represents 15–30% (modern boilers) or 5–10% (old-type boilers) of the total PM mass. Comparison of the results shows that the emission factors for PM obtained by the cyclone were higher than the emission factors obtained using the DLPI.

A Comparison of PAH Emission Sampling Methods (Cyclone, Impactor) in Particulate and Gaseous Phase

“…The boilers, fuels, test set-up, conditions and the emission measurements are presented briefly in this section and were described in detail in our previous work (Krpec et al, 2016;Horak et al, 2017). Only 11 of those 25 combustion tests are included in this study.…”

“…A comparison of the EF PM from the cyclone and the DLPI was described in our previous study (Krpec et al, 2016). The DLPI enabled sorting of PM fractions into PM 0.1 , PM 1 , PM 2.5 and PM 10 , whereas the cyclone enabled sorting of PM into PM 2.5 and PM 10 .…”

“…S1) represent the most frequently used boiler designs for domestic heating in the countries of Central and Eastern Europe. They are described in detail in our previous publications (Krpec et al, 2016;Horak et al, 2017), and the designation of the boilers has been retained as described in our previous publications.…”

“…The mixed fuel was a mixture of lignite (44%), wet spruce logs (34%) and wood chips (9%) placed into polyethylene terephthalate bottles. The wood chips were soaked with used vegetable frying oil (13%) (Krpec et al, 2016). The elementary compositions and calorific values of the fuels were determined prior to the combustion of each fuel (Table S2).…”

Nanoparticle Emission and Characterization from Pre-Dried Lignite and Bituminous Coal Co-Combustion

“…A more comprehensive description of the fly ash particles' formation mechanism from coal combustion can be found in [24], revealing that they have a more effective surface and are more reactive with oxy-anion elements than fly ash particles with supermicron particles. Several studies deal with the characterization of the particulates in terms of composition [25,26] and shape [27,28] from coal combustion and under various conditions [29,30]. Fly ash composition, e.g., alumina content, and shape, e.g., cenospheres content, are related to industrial uses, e.g., alumina recycle, an additive to cement and concrete [27,31], of this inevitable by-product from solid fuel combustion.…”