METHOD AND DEVICE FOR EXPLOITING THE FLUE-GAS HEAT IN BROWN COAL POWER STATIONS WITH WET FLUE-GAS DESULPHURISATION

摘要

The invention relates to a method and a device for exploiting the flue-gas heat in brown coal power stations with wet flue-gas desulphurisaiton. The aim of the invention is to exploit the energy contained in the flue-gas of coal-fired power stations as fully as possible, including in the acid dewpoint range- At the same time, the invention aims to significantly reduce the quantity of fresh water needed for the flue-gas desulphurisation process. To this end, the concentration of dissolved salts in the quantity of flue-gas desulphurisation circulating water provided for quenching is set at a maximum of ∫2 g/l, hereby minimising the formation of oversize material during quenching with said water. A high functioning pH of the washer, together with a 3-stage chemical/physical treatment of the sluiced out circulating water enable the maximum concentration to be set at this level. The introduction of CaCO3 cores (so-called 'pugs') is made possible through the use of burnt lump lime. These grinding bodies which are imminent in the material are used for grinding up the residual hydrated lime oversize, then sluiced out an returned to the grinding device (29). The hydrated lime suspension (34) obtained is then guided directly and exclusively into the lower spray circuits.