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Energy and Environment
Published in T.M. Aggarwal, Environmental Control in Thermal Power Plants, 2021
In the United States and a number of other countries, atmospheric dispersion modeling[14] studies are required to determine the flue gas stack height needed to comply with the local air pollution regulations. The United States also requires the height of a flue gas stack to comply with what is known as the “Good Engineering Practice (GEP)” stack height. In the case of existing flue gas stacks that exceed the GEP stack height, any air pollution dispersion modeling studies for such stacks must use the GEP stack height rather than the actual stack height.
Design and validation of an air-liquid interface (ALI) exposure device based on thermophoresis
Published in Aerosol Science and Technology, 2019
Mika Ihalainen, Pasi Jalava, Tuukka Ihantola, Stefanie Kasurinen, Oskari Uski, Olli Sippula, Anni Hartikainen, Jarkko Tissari, Kari Kuuspalo, Anna Lähde, Maija-Riitta Hirvonen, Jorma Jokiniemi
Flue gas stack under pressure was regulated to be in the range of 6 to 12 Pa. A partial sample of the aerosol was taken from the flue gas stack and diluted by a factor of 1:40 using a porous tube-ejector diluting sampling system (Venacontra, Finland). The diluted sample was supplied for ALI, while simultaneously the size and concentration of particulate phase was monitored with a scanning mobility particle sizer (SMPS, range 14.6–661.2 nm); alveolar deposition surface area with a nanoparticle surface area monitor (NSAM 3350); and total particulate mass with a TEOM. In addition, PM1 filter samples on polytetrafluoroethylene, (PTFE, Pall Corporation, P/N R2PJO47) and Quartz fiber (Pall corporation, Tissuequartz) filters were collected simultaneously with the ALI exposures. The PTFE filters were used for determining the total particulate mass by weighing filters before and after the collection in a microbalance (MT5, Mettler Toledo). Organic carbon and elemental carbon fractions of particles were analyzed with the quartz fiber filters, using the thermal-optical carbon analyzer (Sunlab) and following the protocol NIOSH5040 (Birch 1999). The CO2, NO, and NO2 were measured from the exposure aerosol using trace level single-gas analyzers. The properties of the wood combustion exhaust for each operation condition are shown in Table 1.
Characteristics of particle emissions and their atmospheric dilution during co-combustion of coal and wood pellets in a large combined heat and power plant
Published in Journal of the Air & Waste Management Association, 2019
Fanni Mylläri, Liisa Pirjola, Heikki Lihavainen, Eija Asmi, Erkka Saukko, Tuomas Laurila, Ville Vakkari, Ewan O’Connor, Jani Rautiainen, Anna Häyrinen, Ville Niemelä, Joni Maunula, Risto Hillamo, Jorma Keskinen, Topi Rönkkö
In the “FGD+FF off” situation, the dilution profiles of gaseous CO2 and SO2 and the particle number concentration (ΔNtot) can be clearly seen in Figure 3. All the SO2, CO2, and ΔNtot peaked near the stack. The dilution of gaseous compounds to the background concentrations took approximately 200 sec, which corresponds to distance less than 2 km from the stack. The dilution profile of the ΔNtot was relatively similar than that of gaseous compounds; the ΔNtot peaked near the flue-gas stack and diluted in 200 sec to the background concentrations. In the “FGD+FF on” situation the dilution profiles of gaseous compounds (CO2 and SO2) were relatively similar to those in the “FGD+FF off” situation; clear concentration peaks were measured close to the stack, and after 200 sec the concentrations were at the background level. However, the profile of ΔNtot differed significantly from the “FGD+FF off” situation during the first 500 sec of dilution. First, no significant or separate peak was observed in the beginning of dilution, and second, the ΔNtot remained at higher concentrations for 0–500 sec after the flue gas entered to the atmosphere. Finally, in both of the flue-gas cleaning situations, the particle number concentration increased at the most aged part of the flue gas plume, for “FGD+FF off” after 400 sec and in the “FGD+FF on” situation after 800 sec of atmospheric dilution.
A novel high-volume Photochemical Emission Aging flow tube Reactor (PEAR)
Published in Aerosol Science and Technology, 2019
Mika Ihalainen, Petri Tiitta, Hendryk Czech, Pasi Yli-Pirilä, Anni Hartikainen, Miika Kortelainen, Jarkko Tissari, Benjamin Stengel, Martin Sklorz, Heikki Suhonen, Heikki Lamberg, Ari Leskinen, Astrid Kiendler-Scharr, Horst Harndorf, Ralf Zimmermann, Jorma Jokiniemi, Olli Sippula
Regarding SOA EF related to the mass of burned logwood, 30% lower SOA-EF were obtained for PEAR-aged OA (59–61 mg kg−1) than for smog chamber-aged OA with similar wood fuel and combustion procedure (91 mg kg−1) (Tiitta et al. 2016). SOA formation depends strongly on the concentration and SOA formation potential of the released precursors (Bruns et al. 2016). Batchwise wood combustion is sensitive to the progress of burning shortly after the ignition (Czech et al. 2016), leading to considerable variation of the precursor VOCs. Therefore, the comparison between PEAR and smog chamber experiments should be rather based on EROA than SOA-EF. One of the advantages of using OFR with well-developed laminar flow profile and relatively short residence time is that it enables to study the influence of aging and SOA formation potential of sources with changing emission concentrations, such as cars emissions on driving cycles, wood combustion or ambient air in road tunnel (Karjalainen et al. 2016; Keller and Burtscher 2012; Tkacik et al. 2014). Figure 10 depicts the temporal profiles of spruce logwood combustion emissions, including primary and secondary particle number distributions, aromatic VOC concentrations (measured directly from the flue gas stack), aged OA concentrations, and OA oxidation states at a photochemical age of 6.3 days. At the beginning, the concentrations of aromatic VOC are relatively low and stable, as a result of proper ignition of the logwood. From the ignition until the flaming phase primary particles with a mode of approximately 120 nm are released from the stove, which decrease in size when the flaming phase turn into glowing embers. The addition of subsequent logwood batches causes clearly visible peaks of aromatic VOC concentrations up to 1350 µg m−3. The high abundance of aromatic VOC, which are regarded as potent SOA precursor (Bruns et al. 2016), explains the observed new particle formation in the size of 10–60 nm. However, sharply increasing OA downstream of the PEAR features a distinct lower OSC of +1 compared to aged OA during flaming conditions. This can be explained by two factors. First, the high VOC emissions exhibit a high OH radical consumption, leading to temporarily lower OH exposure when compared to other combustion phases. Second, the ignition of a new batch of logwood generates high POA emissions with O:C of roughly 0.5 (Heringa et al. 2012), which may oxidize heterogeneously (Tiitta et al., 2016) but likely slower than gas-phase species. Thus, the observed aged OA downstream of the PEAR is hypothetically a mixture of less oxidized aged POA and more oxidized SOA. As a whole, the data shows that PEAR with a relatively narrow RTD is also capable to follow the dynamic changes of logwood combustion emissions and thus, can be used to investigate the role of different batchwise-fired logwood stove burning phases (Czech et al. 2016) on secondary aerosol formation.