Hydro/pressurized fluidized bed combustor

A hydro/pressurized fluidized bed combustor comprising:

• an upstanding shell having, at the bottom thereof, an entry port for the low velocity entry of feedstock to said combustor, said feedstock including particulate solid material, air and water;
• an injector pump connected to said entry port for admission of said feedstock;
• an upstanding, contoured entry conduit, having a trumpet-shaped catenoid vertical cross-section gradually enlarging in the upward direction, said conduit being accomodated within the lower half of said upstanding shell and being in communication with said entry port;
• a fluidized bed in the upper portion of said entry conduit, for combustion of said feedstock;
• at least one in-bed steam generation tube located within said combustion zone;
• at least one freeboard steam generation tube located above said combustion zone;
• and
• a weir located above said entry conduit and in communication therewith, said weir acting to extract ash from said fluidized bed at a rate which keeps the height of said bed constant within said combustor during operation thereof.