Process temperature control in oxy/fuel combustion system
AssigneeAir Products and Chemicals, Inc.
InventorMark Daniel D'Agostini
Life of this patent
Estimating the term…
Abstract
An oxy/fuel combustion system having a furnace arranged and disposed to combust a fuel to form a combustion fluid. The system further includes a convective section having at least one heat exchanger arranged and disposed to exchange heat between the combustion fluid and steam for use in a steam turbine. A flue gas recycle is arranged and disposed to recycle at least a portion of the combustion fluid as a recycled flue gas, the flue gas recycle having at least two expellant locations downstream of a primary combustion zone. The system includes a flow control mechanism that provides controlled amounts of the recycled flue gas to the at least two expellant locations to control temperature of the steam.
Claims21
An oxy/fuel combustion system comprising:
- a furnace arranged and disposed to combust a fuel to form a combustion fluid;
- a convective section, the convective section having at least a first heat exchanger and a second heat exchanger downstream from the first heat exchanger, each heat exchanger arranged and disposed to exchange heat between the combustion fluid and steam;
- a flue gas recycle arranged and disposed to recycle at least a portion of the combustion fluid as a recycled flue gas, the flue gas recycle having two expellant locations downstream of a primary combustion zone and wherein at least one of the expellant locations is downstream of at least one of the heat exchangers;
- and
- a flow control mechanism arranged and disposed to selectively provide the recycled flue gas to the combustion fluid, the flow control mechanism having a plurality of conduits and capable of controlling flow of recycled flue gas;
- wherein one of the expellant locations is immediately upstream of the first heat exchanger and another of the expellant locations is downstream of the first heat exchanger and immediately upstream of the second heat exchanger;
- and
- wherein the flow control mechanism provides controlled amounts of the recycled flue gas to the two expellant locations and independently controls temperature of the steam at the two expellant locations.
A method of combustion comprising the steps of:
- combusting a solid fuel with an oxidant having an O2 concentration greater than air, in a furnace to form a combustion fluid and exchanging heat between the combustion fluid and steam;
- delivering the combustion fluid to a convective section having a first heat exchanger and a second heat exchanger downstream from the first heat exchanger and exchanging heat between the combustion fluid and steam in the heat exchangers;
- supplying the steam to a steam turbine;
- recycling at least a portion of the combustion fluid as recycled flue gas to two expellant locations downstream of a primary combustion zone, one expellant location being immediately upstream of the first heat exchanger and another expellant location being downstream of the first heat exchanger and immediately upstream of the second heat exchanger;
- and
- selectively providing recycled flue gas to at least two expellant locations to independently control temperature of the steam in a plurality of steam conduits.
Dependencies are inferred from the claim text.