At combustion of hospital waste numerous harmful pollutants were formed inclusive persistent PCDD/F （polychlorinated dibenzodioxines and dibenzofuranes） compounds. To eliminate these substances an existing incinerat...At combustion of hospital waste numerous harmful pollutants were formed inclusive persistent PCDD/F （polychlorinated dibenzodioxines and dibenzofuranes） compounds. To eliminate these substances an existing incinerator consisting of the furnace heat exchanger with flue gas cleaning was used. This incinerator had a capacity of 250 kg of waste per hour. Elimination od acid gases was executed by dosing of solid sorbents （calcium hydrate and bicarbonate） at two points of the waste gases duct. Local temperatures of waste gases at these two points were different. Sorbents were dosed at different distances from the textile filter by which ash and sorbent were separated from the stream of waste gases. By this arrangement it was possible to alter the residence time of sorbents in waste gases. The effect of addition of bicarbonate on dechlorination and desulphurisation was also studied. The executed experiments indicated that at dosing of calcium hydroxide into waste gases at higher temperatures sulphur oxides reacted preferably to hydrogen chloride. The strong effect of HCI in waste gases on formation of PCDD/F was proved. For sufficient elimination of persistent compounds from waste gases it was necessary to add beside calcium hydrate also active carbon. Two types of sorbents based on carbon were tested, namely Norit and Chezacarb B. Both were macroporous. Chezacarb B was carbon black from the process of hydrogen production by partial oxidation. Efficiency of both sorbents for removal of PCDD/F was similar.展开更多
文摘At combustion of hospital waste numerous harmful pollutants were formed inclusive persistent PCDD/F （polychlorinated dibenzodioxines and dibenzofuranes） compounds. To eliminate these substances an existing incinerator consisting of the furnace heat exchanger with flue gas cleaning was used. This incinerator had a capacity of 250 kg of waste per hour. Elimination od acid gases was executed by dosing of solid sorbents （calcium hydrate and bicarbonate） at two points of the waste gases duct. Local temperatures of waste gases at these two points were different. Sorbents were dosed at different distances from the textile filter by which ash and sorbent were separated from the stream of waste gases. By this arrangement it was possible to alter the residence time of sorbents in waste gases. The effect of addition of bicarbonate on dechlorination and desulphurisation was also studied. The executed experiments indicated that at dosing of calcium hydroxide into waste gases at higher temperatures sulphur oxides reacted preferably to hydrogen chloride. The strong effect of HCI in waste gases on formation of PCDD/F was proved. For sufficient elimination of persistent compounds from waste gases it was necessary to add beside calcium hydrate also active carbon. Two types of sorbents based on carbon were tested, namely Norit and Chezacarb B. Both were macroporous. Chezacarb B was carbon black from the process of hydrogen production by partial oxidation. Efficiency of both sorbents for removal of PCDD/F was similar.
