THERMAL VALORIZATION - WITH COBALT AND MANGANSE RECOVERY - OF VARIOUS BY-PRODUCTS OF A CHEMICAL PLANT IN A FLUIDISED BED BOILER FOLLOWED BY HIGH-TEMPERATURE FILTRATION AND CATALYTIC OXIDATION OF DIOXINS AND FURANS

摘要

The potential of co-combustion of industrial WWTP-sludge and five by-products of a chemical industry was evaluated in a semi-industrial atmospheric fluidised bed furnace. The chemical by-products had high concentrations of cobalt and manganese, with elevated concentrations of bromine and sulphur. Recovery of Co and Mn was desired. An efficient, complete and autothermal combustion was achieved under all conditions and waste compositions. The process steam generated from co-combustion will cover about 5-10% of the total steam consumption of the chemical production plant. Ni, Co, and Mn were recovered in the fly ashes with an efficiency of up to 90%. The concentration and chemical composition allow recovery of Co and Mn. The full-scale unit (10 MWth) is currently in the design and construction phase and will consist of a bubbling fluidised bed furnace with integrated steam boiler (43 bara, saturated), a two-stage, dry sorbent injection, a ceramic high-temperature filter for acid and dust removal and metal recovery, and a catalytic reactor for oxidation of dioxins/furans and reduction of NOx.