Patent ID: 8192514

Claim:
A counter-current fixed bed coal gasifier, which includes an upright cylindrical wall defining a coal gasification chamber in which coal, in the form of a fixed coal bed, can be gasified to produce synthesis gas as well as ash in an ash bed below the coal bed; a coal lock above the chamber, the coal lock having a centrally located coal discharge opening which is in communication with the coal gasification chamber and a displaceable closure member for closing off the coal discharge opening, the closure member being displaceable between a closed position in which it closes off the coal discharge opening and an open position in which the coal discharge opening is uncovered or open so that coal can pass under gravity from the coal lock through the coal discharge opening into the coal gasification chamber; a static coal distribution device inside the coal gasification chamber, the static coal distribution device including a hollow coal distributor having an upper open end spaced from the coal discharge opening and which flares downwardly outwardly from its upper end to a lower open end thereof and with no static coal distribution device being provided between the upper end of the coal distributor and the coal discharge opening other than the closure member; a skirt with an open upper end depending downwardly from the inside of the coal distributor so that a gas collection zone is defined between the skirt and the coal distributor, with the top of the gas collection zone being closed off while the bottom thereof is in communication with the coal gasification chamber; and at least one gas outlet in the coal distributor, with the gas outlet being in communication with the gas collection zone, a first coal passageway thus being defined between the coal distributor and the cylindrical wall while a second coal passageway is provided along and defined by the inside of the skirt; a gas withdrawal conduit leading from the gas outlet of the coal distribution device through the wall of the coal gasification chamber; an ash discharge outlet leading from the chamber at a low level; and a rotatable grate above the ash discharge outlet, the rotatable grate including at least one upwardly projecting finger or disturbing formation to disturb the ash bed formed in use above and around the rotatable grate, when the rotatable grate is rotated.