High temperature furnace with improved slag tap

In a high temperature, furnace for generating hot gases from the combustion of particulate organic material, the material having an ash content, the gases having a temperature above the melting temperature for the ash so that the ash is transformed into molten slag while in the furnace, the furnace including a combustion chamber having first and second ends, a burner near the first end of the combustion chamber for introducing the material into the chamber, means for supplying combustion air, and a duct near the second end of the combustion chamber for withdrawing the hot gases, an improved slag tap into which the slag passes comprising:

• means defining a slag-receiving chamber below the combustion chamber, the slag-receiving chamber defining a downwardly open hole at its bottom;
• means defining a conduit communicating the combustion chamber with the slag-receiving chamber;
• means for maintaining a volume of water substantially immediately below the slag-receiving chamber;
• wherein slag generated in the chamber flows through the conduit, through the slag-receiving chamber, and into the water where it solidifies;
• means defining openings communicating the slag-receiving chamber with the exterior;
• and
• means for withdrawing gas from the slag-receiving chamber through the openings;
• such that a portion of the hot gases in the combustion chamber is drawn through the conduit, into the slag-receiving chamber, and hence through the openings to the exterior of the slag-receiving chamber to thereby maintain the temperature of the slag-receiving chamber at about the level of the temperature in the combustion chamber and the slag passing therethrough in a molten state.

Apparatus for generating hot gases from the combustion of ash-bearing organic material comprising:

• a vertical combustion chamber having an upper portion and a lower portion, the lower portion being tapered to define a relatively small opening at the bottom;
• a burner for combusting dried pulverized organic material, mounted above the upper portion of the combustion chamber;
• a generally horizontal first duct below the upper portion of the combustion chamber for withdrawing from the combustion chamber the hot gases resulting from the combustion;
• means at the bottom of the combustion chamber defining a generally vertical passageway extending from the opening;
• a first generally cylindrical wall defining a slag-receiving chamber below the combustion chamber and in fluid communication with the opening, the slag-receiving chamber having a diameter at its top that is larger than the transverse dimensions of the vertical passageway, the wall having a plurality of apertures extending radially therethrough, the slag-receiving chamber being tapered at its bottom, and being open at its bottom;
• a second coaxial wall having an inner diameter greater than the outer diameter of the first coaxial wall, thereby defining an annular plenum between the first and second walls;
• means for maintaining a volume of water beneath the opening in the bottom of the slag-receiving chamber;
• a mill adapted to supply dried pulverized material to the burner;
• a second duct leading from the plenum to a mill;
• and
• means for causing gas within the plenum to flow through the second duct to the coal mill and for drying organic material therein with such gas;
• wherein slag from the burning material in the combustion chamber passes through the passageway, into the slag-receiving chamber, and therethrough into the water where it solidifies while a portion of the hot gases passes through the passageway, into the slag-receiving chamber, radially outward through the radially extending apertures, into the plenum, into the second duct, and into the mill, and the hot gases maintain the slag-receiving chamber and the slag therein at a temperature approximating that of the combustion chamber to prevent the slag from solidifying before reaching the water.

A high temperature furnace for generating hot gases from the combustion of particulate organic matter comprising:

• a combustion chamber having an upper portion and a lower portion, the combustion chamber having a lower inclined wall extending between the portions;
• a burner for combusting dried pulverized organic matter mounted at the upper portion of the combustion chamber;
• a duct at the lower portion of the combustion chamber for withdrawing the hot gases;
• and
• at least one slag tap disposed along the lower inclined wall, the slag tap comprising
• means defining an opening in the lower inclined wall,
• means defining a generally vertical passageway extending from the opening,
• means defining a slag-receiving chamber below the passageway and in communication with the combustion chamber via the passageway,
• means defining an annular plenum surrounding the slag-receiving chamber,
• means between the slag-receiving chamber and the plenum for providing gas communication therebetween, and
• means for withdrawing gas from the plenum,
• such that a portion of the hot gases is withdrawn through the passageway, into the slag-receiving chamber, through the openings, into the plenum, and out the plenum, thereby maintaining the temperature of the slag-receiving chamber at a temperature approximately that of the combustion chamber, whereby the slag is prevented from solidifying.

In a process for generating hot gases including the step of burning pulverized ash-bearing organic material in a combustion chamber, the gases having a sufficient temperature to melt the ash and form a slag so that at least a portion of the slag precipitates out of the gas stream, the improvement comprising the steps of:

• providing a downwardly open slag-receiving chamber beneath and communicating with the combustion chamber;
• passing the slag into and through the slag-receiving chamber;
• withdrawing a predetermined portion of the hot gases;
• and
• heating the slag passing through the slag-receiving chamber with the portion of hot gases sufficiently to maintain the slag in its molten state while disposed within the open chamber;
• whereby the slag is prevented from solidifying until after it has passed through a portion of the slag-receiving chamber.

In a high temperature furnace for generating hot gases by combusting an ash-bearing fuel, the furnace including a combustion chamber, a burner near one end of the combustion chamber for generating the hot gases, and a duct near the other end of the combustion chamber through which the hot gases pass out of the combustion chamber, the temperature of the gases being sufficiently high to melt ash in the fuel to form molten slag, an improved slag tap into which slag flows comprising:

• means defining a downwardly open slag-receiving chamber disposed below a portion of and in flow communication with the combustion chamber;
• and
• means for withdrawing a portion of the hot gases from the combustion chamber and for heating slag passing through the slag-receiving chamber sufficiently with the portion of the hot gases to maintain such slag in its molten state, thereby preventing it from solidifying while in the slag-receiving chamber, the withdrawing and heating means including means for passing the portion of hot gases through the slag-receiving chamber, means defining a plenum surrounding the slag-receiving chamber, means defining a plurality of openings between the plenum and the slag-receiving chamber, and means for evacuating the hot gas from the plenum, whereby the portion of hot gases passes from the combustion chamber, into the slag-receiving chamber, through the openings, and into the plenum, thereby heating the slag-receiving chamber and slag passing therethrough.

In a process for generating hot gases including the step of burning pulverized ash-bearing organic material in a combustion chamber, the gases having a sufficient temperature to melt the ash and form a slag so that at least a portion of the slag precipitates out of the gas stream, the improvement comprising the steps of:

• providing a downwardly open slag-receiving chamber beneath and communicating with the combustion chamber;
• passing the slag into and through the slag-receiving chamber;
• withdrawing a portion of the hot gases;
• heating the slag passing through the slag-receiving chamber with the portion of hot gases sufficiently to maintain the slag in its molten state while disposed with the open chamber;
• whereby the slag is prevented from solidifying until after it has passed through a portion of the slag-receiving chamber;
• and
• directing the portion of hot gases to a mill for drying organic material prior to combustion of the organic material.