Influence of coal combustion temperature on polycyclic aromatic hydrocarbons formation in coal fired power plants and its consequences on the environment

Naučni cilj istraživanja obuhvaćenog ovom doktorskom disertacijom je ispitivanje i utvrđivanje mehanizama formiranja policikličnih aromatičnih ugljovodonika (PAH) in situ, tokom sagorevanja uglja i promene temperature sagorevanja u termoelektrani „Nikola Tesla B“, kao i istraživanje njihove sudbine (razlaganja i degradacije) u proizvodima sagorevanja tokom transporta i nakon odlaganja na deponiju pepela i šljake. Količine policikličnih aromatičnih ugljovodonika su ispitivane u uglju koji se koristi u termoelektrani, proizvodima nastalim sagorevanjem uglja pri različitim temperaturama (različitim tipovima pepela i šljake), kao i u deponijskom pepelu i šljaci sa aktivne, trenutno korišćene, i pasivne, ranije korišćene kasete deponije. Ekstrakcija PAH-ova iz čvrstih uzoraka je rađena pomoću ultrazvuka u odgovarajućem rastvaraču, dok je analiza pripremljenih uzoraka izvedena pomoću gasnog hromatografa povezanog sa masenim detektorom. Ispitivana je i ekstraktibilnost PAH-ova iz elektrofilterskog pepela u uslovima koji oponašaju one koji mogu biti prisutni u životnoj sredini. Ekstrakcija PAH-ova iz pripremljenih tečnih uzoraka vršena je rastvaračem u levku za odvajanje, dok je analiza pripremljenih uzoraka izvođena pomoću gasnog hromatografa povezanog sa masenim detektorom. Zaključeno je da sa porastom temperature sagorevanja lignita u termoelektrani Nikola Tesla B, ukupna količina PAH-ova u proizvodima sagorevanja raste u temperaturnom opsegu od 930 do 973,5 oC, dok sa daljim povećanjem temperature ukupna količina ostaje konstantna. PAH-ovi u pepelu i šljaci se ponašaju različito: količine PAH-ova rastu u pepelu zbog njihove sinteze tokom sagorevanja u ložištu i zbog njihovog povećanog isparavanja usled povećanih...The scientific aim of the research covered by this dissertation is to examine and determine the mechanisms of formation of polycyclic aromatic hydrocarbons in situ during the combustion of coal and variation of temperature combustion in thermal power plant "Nikola Tesla B", as well as the study of their fate (decomposition and degradation) in the products of combustion during the transport and after deposition of ash and slag. The concentrations of polycyclic aromatic hydrocarbons were tested in coal used in thermal power plant, coal combustion products formed by the combustion of coal at different temperatures (various types of fly ash and slag), as well as ash and slag from active, currently used, and passive, previously used cassette of ash dump. Extraction of PAH’s from solid samples was carried out by means of ultrasound in a suitable solvent, while the analysis of the prepared samples was performed using gas chromatography with mass detector. The extractability of PAHs in fly ash in conditions that mimic those that may be present in the environment was investigated. Extraction of PAHs from the prepared liquid samples was carried out using solvent in a separating funnel, while the analysis of the prepared samples was performed by gas chromatography with mass detector. It is concluded that with increasing of combustion temperature of lignite in the thermal power plant Nikola Tesla B, the total amount of PAHs in the products of combustion increases from 930 to 973.5 °C, and with a further increase in temperature total amount becomes constant. PAHs in ash and slag behave differently: the quantities of PAHs are increasing in ash because of their synthesis during combustion in the furnace and because of their increased evaporation due to increased temperature, resulting in, among other things, the presence of PAHs..