In the field of municipal solid waste disposal, the direct melting process of the coke-bed type shaft furnace is effective in prolonging the useful life of the final disposal sites and reducing harmful matter such as dioxins. However, recently, it has become necessary to reduce coke consumption for the direct melting process in order to prevent global warming and reduce maintenance costs. Accordingly, the authors have developed technology for injecting various combustibles through the tuyeres of the direct melting furnace. In particular, combustible dust in the pyrolysis gas dischanged from the furnace top was focused to reduce coke consumption. In this study, some experiments on combustible dust injection through the tuyeres were carried out by using an experimental plant and a commercial facility.
The main results obtained are as follows:
(1) Combustible dust injected through the lower tuyeres is consumed by combustion and melting in the furnace. This technology is effective in reducing coke consumption and fly ash.
(2) Combustible dust injection through the tuyeres maintains low Pb concentration in the slag even under the condition of low coke ratio. Moreover, combustibility in the combustion chamber is improved, and the generation of dioxins is suppressed.
