Method and system for low-NO_x dual-fuel combustion of liquid and/or gaseous fuels

摘要

A method and apparatus for combustion in which a pressurized preheated liquid fuel is atomized and a portion thereof flash vaporized, creating a mixture of fuel vapor and liquid droplets. The mixture is mixed with primary combustion oxidant, producing a fuel/primary oxidant mixture which is then injected into a primary combustion chamber in which the fuel/primary oxidant mixture is partially combusted, producing a secondary gaseous fuel containing hydrogen and carbon oxides. The secondary gaseous fuel is mixed with a secondary combustion oxidant and injected into the second combustion chamber wherein complete combustion of the secondary gaseous fuel is carried out. The resulting second stage flue gas containing very low amounts of NOx is then vented from the second combustion chamber.

主权项

1. A method for dual-fuel combustion comprising the steps of:
pressurizing a liquid fuel, wherein a means of pressurizing the liquid fuel comprises a low pressure liquid fuel inlet and a high pressure liquid fuel outlet; preheating the pressurized liquid fuel, wherein a means of preheating the pressurized liquid fuel comprises at least one of an electric liquid fuel preheater, a water-liquid fuel preheater, and a steam-liquid fuel preheater; wherein said pressurized liquid fuel preheating means further comprises a water-fuel heater having a pressurized preheated liquid fuel inlet in fluid communication with said means of preheating the pressurized liquid fuel and having a pressurized preheated water inlet in fluid communication with a pressurized water preheater; atomizing the preheated liquid fuel, producing an atomized liquid fuel; flash vaporing up to about 50% of said atomized liquid fuel, producing a liquid fuel mixture comprising said atomized liquid fuel and a vaporized fuel; mixing said liquid fuel mixture with a primary combustion oxidant in a mixing chamber, producing a fuel/oxidant mixture having a primary stoichiometry less than about 1.0; introducing said fuel/oxidant mixture into a first combustion chamber in which partial combustion of said fuel/oxidant mixture occurs, producing a secondary fuel gas; cooling said secondary fuel gas, producing a cooler secondary fuel gas; mixing said cooler secondary fuel gas with a secondary combustion oxidant, producing a secondary fuel gas/oxidant mixture; introducing said secondary fuel gas/oxidant mixture into a second combustion chamber in which substantially complete combustion of said secondary fuel gas/oxidant mixture occurs, producing flue gases; and venting said flue gases from said second combustion chamber.