Removal of dioxins and related aromatic hydrocarbons from flue gas streams by adsorption and catalytic destruction.
The dioxin removing capacity of the shell dedioxin system (SDDS-a Ti/V oxidative type catalyst) has been tested using the Umeå lab-scale incinerator over the temperature range 100-230 degrees 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 degrees C (82%), which occurs mainly by adsorption. When the temperature is raised a transition towards destruction is seen and at 150 degrees C, gas hour space velocity (GHSV) 8000 and at 230 degrees 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 degrees C.
Liljelind
P
P
Environmental Chemistry, Chemistry Department, Umeå University, Sweden. per.liljelind@chem.umu.se
Unsworth
J
J
Maaskant
O
O
Marklund
S
S