Method of conditioning fireside fouling deposits using large particle size amorphous silica

Claim 2

Method of minimizing the deleterious effects of combustion residues emanating from coal burned as fuel in a boiler of the type having a furnace combustion zone in which said coal is burned and a convection zone located downstream from said combustion zone, said method comprising adding amorphous silica particles to said boiler in an amount of between about trace-2.0% by weight of said particles (based upon the weight of said residues) at a location upstream from said convection zone, wherein at most about 10% of said particles, by volume, are greater than about 170 microns in diameter and wherein at least about 90%, by volume, of said particles are greater than about 38 microns in diameter.

Claim 3

Method as defined in claim 1 comprising adding between about 0.5%-1.0% by weight of said particles (based upon the weight of said residues).

Claim 4

Method of minimizing the deleterious effects of combustion residues emanating from coal burned as fuel in a boiler of the type having a furnace combustion zone in which said coal is burned, said method comprising adding amorphous silica particles directly to said coal in said combustion zone in an amount of between trace-2.0% by weight of said particles (based upon the weight of said residues), wherein at most about 10% of said particles, by volume, are greater than about 170 microns in diameter and wherein at least about 90%, by volume, of said particles are greater than about 38 microns in diameter.

Claim 5

Method of minimizing the deleterious effects of combustion residues emanating from coal burned as fuel in a boiler of the type having a furnace combustion zone in which said coal is burned, said method comprising adding amorphous silica particles directly to said coal in said combustion zone in an amount of between trace-2.0% by weight of said particles (based upon the weight of said residues), wherein at most about 10% of said particles, by volume, are greater than about 170 microns in diameter and wherein at least about 90%, by volume, of said particles are greater than about 38 microns in diameter.

Claim 6

Method as defined in claim 2 comprising adding between about 0.5%-1.0% by weight of said particles (based upon the weight of said residues).

Claim 7

In a coal fired boiler of the type having a combustion zone in which said coal is fired, a convection zone located downstream from said combustion zone and having a plurality of heater tubes disposed in said convection zone and adapted to heat water or steam disposed therein, and in which convection zone combustion residues emanating from said coal have a tendency to stick to or agglomerate upon said tubes, a method of decreasing said tendency to stick or agglomerate, comprising burning said coal in the presence of an additive consisting essentially of amorphous silica particles, wherein at most about 10% of said particles, by volume, are greater than about 170 microns in diameter and wherein at least about 90%, by volume, of said particles are greater than about 38 microns in diameter, and wherein said particles are added to said boiler in an amount of between about trace-2.0% by weight of said particles based upon the weight of said combustion residues.

Claim 8

In a coal fired boiler of the type having a combustion zone in which said coal is fired, a convection zone located downstream from said combustion zone and having a plurality of heater tubes disposed in said convection zone and adapted to heat water or steam disposed therein, and in which convection zone combustion residues emanating from said coal have a tendency to stick to or agglomerate upon said tubes, a method of decreasing said tendency to stick or agglomerate, comprising burning said coal in the presence of an additive consisting essentially of amorphous silica particles, wherein at most about 10% of said particles, by volume, are greater than about 170 microns in diameter and wherein at least about 90%, by volume, of said particles are greater than about 38 microns in diameter, and wherein said particles are added to said boiler in an amount of between about trace-2.0% by weight of said particles based upon the weight of said combustion residues.

Claim 9

Method as defined in claim 5 comprising adding between about 0.5%-1.0% by weight of said particles based upon the weight of said combustion residues.