25323-68-6Relevant articles and documents
Removal of dioxins and related aromatic hydrocarbons from flue gas streams by adsorption and catalytic destruction
Liljelind, Per,Unsworth, John,Maaskant, Onno,Marklund, Stellan
, p. 615 - 623 (2007/10/03)
The dioxin removing capacity of the shell dedioxin system (SDDS a - Ti/V oxidative type catalyst) has been tested using the Umefa lab-scale incinerator over the temperature range 100 -230°C and at space velocities of 8000 and 40,000 h-1. Other analogous organic compounds, such as PCBs, PAHs, chlorobenzenes and chlorophenols have also been investigated. Results show a high degree of dioxin removal already at 100°C (82%), which occurs mainly by adsorption. When the temperature is raised a transition towards destruction is seen and at 150°C, gas hour space velocity (GHSV) 8000 and at 230°C, GHSV 40,000 virtually all removal is by destruction. High PCDD/F destruction efficiencies are reported (> 99.9%, based on I-TEQ); the other dioxin-related species and PAHs are also removed and destroyed to a significant extent. The SDDS has proved to be an effective means of destroying organic compounds in the gas phase, particularly dioxins, at temperatures as low as 150°C.
Influence of variation in combustion conditions on the primary formation of chlorinated organic micropollutants during municipal solid waste combustion
Wikstroem,Tysklind,Marklund
, p. 4263 - 4269 (2007/10/03)
The aim of this study was to investigate the influence of variation in combustion conditions on the primary formation of organic micropollutants (OMPs). The flue gas samples were taken at a relatively high flue gas temperature (650°C), to enable mechanistic studies on the high temperature formation (primary formation). Eleven experiments were performed in a laboratory scale fluidized bed reactor fed with an artificial municipal solid waste (MSW). The samples were analyzed for mono- to octachlorinated dibenzo- p-dioxins and dibenzofurans (CDDs/Fs), tri- to decachlorinated biphenyls (CBs), di- to hexachlorinated benzenes (CBzs), and di- to pentachlorinated phenols (CPhs). In addition to chlorinated OMPs, nonchlorinated dibenzo-p- dioxin (DD), dibenzofuran (DF), and biphenyl (BP) were analyzed. The experiments show that variations in the CE influence the degree of chlorination of the organic micropollutants. A correlation between low CE and formation of non- and low-chlorinated DMPs was seen and a distinct relationship of higher chlorinated homologues and efficient combustion condition. Thus, the DiCDFs and DiCBzs are formed during low combustion efficiency (CE), while the PeCDF and PeCBzs formation take place at higher CE. The distribution between primary and secondary air is important for the formation of higher CDD/Fs and CBzs. The primary formation of CDDs and CDFs is through different mechanisms. The CDDs are mainly formed by condensation of CPhs, while the CDFs are formed through a non- or a low-chlorinated precursor followed by further chlorination reactions.
