Low NOx gas burner with cooled flue gas recycle
AssigneeHoneywell International Inc.
InventorsKurt E. Kraus, Dusty Ray Richmond, Mohammad Reza Mostofi-Ashtiani, Zhili Qin
Life of this patent
Estimating the term…
Abstract
A burner and methods of using the burner. The burner produces a flame from combustion air and fuel gas. Flue gas, also produced, can be withdrawn and recycled to the burner. A cooling or condition gas, such as ambient air, may be mixed with the flue gas to reduce its temperature. The burner may also utilize a stage injection so that a portion of the produced flue gas is recycled internally.
Claims18
A burner configured to receive a fuel gas and a combustion air which react and produce a flame and a flue gas in a combustion zone, the burner comprising:
- primary injection ports configured to inject a fuel gas into a primary combustion zone;
- secondary injection ports spaced from the primary combustion zone and configured such that as fuel gas is injected and a first portion of the flue gas is drawn to the primary combustion zone;
- a duct configured to remove a second portion of the flue gas from the combustion zone and return the second portion of the flue gas to the primary combustion zone, and,
- an inlet configured to provide a cooling gas to the first portion of the flue gas,
- wherein the first portion of the flue gas is mixed, upstream of the combustion zone, with the fuel gas and the combustion air and the cooling gas is provided to the first portion of the flue gas upstream of mixing of the first portion of the flue gas with the fuel gas and the combustion air.
A heating system comprising:
- a burner configured to receive a fuel gas and a combustion air which react and produce a flame and a flue gas in a combustion zone;
- a duct configured to remove a first portion of the flue gas from the combustion zone as a recycled flue gas, wherein the first portion of the flue gas is mixed, upstream of the combustion zone, with the fuel gas and the combustion air;
- an inlet configured to provide a cooling gas to the first portion of the flue gas;
- and
- a second duct configured to remove a second portion of the flue gas from the heating system,
- wherein the second portion of the flue gas has passed through a convection zone of the heating system,
- wherein the convection zone is disposed downstream from the combustion zone, and
- wherein the second portion of the flue gas is mixed, upstream of the combustion zone, with the fuel gas and the combustion air, and
- wherein the cooling gas is provided to the first portion of the flue gas upstream of the mixing of the first portion of the flue gas with the fuel gas and the combustion air.
A method of controlling a burner, the method comprising:
- reacting, in a combustion zone of a heating system, a fuel gas and a combustion air to produce a flame and a flue gas;
- removing a first portion of the flue gas from the combustion zone as a recycled flue gas;
- mixing the first portion of the flue gas, upstream of the combustion zone, with the fuel gas and the combustion air;
- removing a second portion of the flue gas from the heating system, wherein the second portion of the flue gas has passed through a convection zone, wherein the convection zone is downstream of the combustion zone;
- mixing the second portion of the flue gas, upstream of the combustion zone, with the fuel gas and the combustion air;
- and,
- mixing a cooling gas with the first portion of the flue gas,
- wherein the cooling gas is mixed with the first portion of the flue gas upstream of the mixing of the first portion of the flue gas with the fuel gas and the combustion air.
Dependencies are inferred from the claim text.