Patent ID: 7331313

Claim:
A continuous steam generator having a circulating atmospheric fluidized-bed firing system comprising: a fluidized-bed combustion chamber, in which the fluidized-bed combustion chamber is essentially defined on all sides by enclosing walls, having gas-tight tubular walls essentially comprising vertical heat exchange tubes and in the lower area at least one funnel, and the fluidized-bed combustion chamber is embodied with at least one essentially vertically disposed heating surface equipped with vertical heat exchange tubes, whereby the heating surface is comprised of a welded tube-web-tube combination, and whereby the tubes of the enclosing walls and the heating surface have a water/steam working medium passing through them, wherein all tubes of the enclosing walls and the heating surface are configured as an evaporator heating surface, and they are connected in parallel so that all of the working medium that is to be evaporated can pass through them, all tubes of the enclosing walls are configured with a tube surface area that is smooth on the inside, and the heating surface extends between the bottom of the combustion chamber or the top of the funnel edge and the combustion chamber cover; and a separator disposed externally to the fluidized-bed combustion chamber, the separator having an inlet in fluid communication with an upper portion of the fluidized-bed combustion chamber and an outlet in fluid communication with a lower portion of the fluidized-bed combustion chamber, the separator receiving a flue gas from the fluidized-bed combustion chamber, removing solids entrained in the flue gas, and returning the solids to the fluidized-bed combustion chamber; whereby heat produced by combustion is transferred from a fluidized-bed, comprising a mixture of gas and entrained solids, to substantially the entire heating surface and the enclosing walls.