Industrial boiler utilizing multiple fuels and having reduced particulate emission and method of combustion

A boiler adapted to burn coal with reduced particulate emission, said boiler including

• a combustion chamber and a fire-tube section, said combustion chamber being positioned below said fire-tube section and having a flue gas exit at one end thereof to discharge hot combustion gases from said combustion chamber,
• said combustion chamber including a coal-burning area and a combustion gas passage from said coal-burning area to said flue gas exit,
• said coal-burning area being beneath a major portion of said fire-tube section but not directly beneath said flue gas exit, whereby passage of coal combustion gases from said coal-burning area through said combustion gas passage is at an angle from the vertical,
• said combustion chamber further including an oil or gas burner removed from said coal-burning area positioned at the opposite end of said combustion chamber from said coal-burning area and below and proximate to said flue gas exit, said burner being directed so that its flame extends horizontally through said combustion gas passage toward the end of the combustion chamber having said coal-burning area, past said flue gas exit, across the path of said coal combustion gases, whereby the direction of the flame from said burner opposes the direction of flow of said coal combustion gases and particulate emission resulting from burning of coal, and
• means for varying the relative quantities of coal and oil or gas being burned.