Methods of utilizing boiler blowdown for reducing nox
AssigneeJohn Zink Company
InventorsJohn P. Guarco, Andrew S. Barrieau, Lev M. Tsirulnikov
Life of this patent
Estimating the term…
Abstract
The present invention provides improved methods of reducing NOx emissions in the flue gases produced by a steam boiler fired by a fluid fuel and combustion air burner and including a steam drum provided with make-up water from which produced steam and blowdown steam are withdrawn. In accordance with the invention at least a portion of the blowdown steam is combined with the fluid fuel or combustion air or both.
Claims26
In a method of reducing the NOx emissions in the flue gases produced by a steam boiler fired by a fluid fuel and combustion air burner and including a steam drum provided with make-up water and from which produced steam and blowdown steam are withdrawn, the blowdown steam being withdrawn to maintain appropriate total dissolved solids in the boiler water, the improvement which comprises combining at least a portion of said blowdown steam with said fluid fuel.
An improved method of reducing the NOx emissions in the flue gases produced by a steam boiler fired by a fluid fuel and combustion air burner and including a steam drum provided with make-up water and from which produced steam and blowdown steam are withdrawn, the blowdown steam being withdrawn to maintain appropriate total dissolved solids in the boiler water, comprising the steps of:
- (a) combining a portion of said flue gases with said combustion air;
- and
- (b) combining a portion of said blowdown steam with said fluid fuel.
An improved method of reducing NOx emissions in the flue gases produced by a steam boiler fired by a fluid fuel and combustion air burner and including a steam drum provided with make-up water and from which produced steam and blowdown steam are withdrawn, the blowdown steam being withdrawn to maintain appropriate total dissolved solids in the boiler water, comprising the steps of:
- (a) combining a portion of said flue gases with said combustion air;
- (b) combining a portion of said blowdown steam with said combustion air;
- (c) combining a portion of said flue gases with said fluid fuel;
- and
- (d) combining a portion of said blowdown steam with said fluid fuel.
An improved method of reducing NOx emissions in the flue gases produced by a steam boiler fired by a fluid fuel and combustion air burner and including a steam drum provided with make-up water and from which produced steam and blowdown steam are withdrawn, the blowdown steam being withdrawn to maintain appropriate total dissolved solids in the boiler water, comprising the steps of:
- (a) withdrawing a blowdown stream of steam and water from said steam drum containing a minor portion of said blowdown steam and a major portion of said water having a high level of dissolved solids therein;
- (b) purifying said water withdrawn from said steam drum in accordance with step (a) and recirculating the purified water as a part of said make-up water to said steam drum;
- (c) combining a portion of said flue gases produced by said boiler with said combustion air;
- and
- (d) combining at least a portion of said blowdown steam withdrawn in accordance with step (a) from said steam drum with said fluid fuel.
Dependencies are inferred from the claim text.