US 8,689,709 B2Granted

Oxycombustion in transport oxy-combustor

AssigneeThe Southern Company

InventorsPannalal Vimalchand, Guohai Liu, WanWang Peng

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Abstract

A pressurized transport oxy-combustor with different configurations is disclosed. Substantially pure oxygen is fed to the transport oxy-combustor under pressure to combust fossil fuels, generating steam for power generation. The end product is the flue gas containing substantially pure CO2 after moisture condensation. The low excess oxygen necessary to achieve complete combustion in the combustor is scavenged by adding another fuel so that substantially all oxygen fed to the combustor is completely consumed. The capability to operate the transport oxy-combustor as a circulating fluidized bed combustor at very high solids circulation rates makes it unnecessary to use recycled CO2 or flue gas as a means to moderate and control the combustion temperature. The temperature in the combustor is effectively controlled by relatively cooler circulating solids that enter the combustion zone. A small amount of CO2 is recycled for aeration and to convey solids fuel to the combustor.

Claims22

Dependent claims

A pressurized transport oxy-combustor comprising:

a riser comprising a shell and insulation and erosion resistant refractory liners, wherein in the riser carbonaceous solids fuel is combusted in the presence of substantially pure oxygen and circulating solids, which combustion forms a flue gas stream comprising a gas-solids mixture;
a first stage cyclone having an inclined tangential inlet;
an inclined first crossover connecting the riser top with the first stage cyclone;
a second stage cyclone;
a second crossover connecting the first stage cyclone exit to the second stage cyclone;
a third stage cyclone consuming excess oxygen in the flue gas stream with a scavenging fuel;
a standpipe;
a seal-leg under at least one of the first and second stage cyclones to return solids to the standpipe, and to provide a seal from a reverse flow of the flue gas stream;
and
at least one solids cooler, wherein the standpipe provides communication between the cyclones to the at least one solids cooler;
wherein the at least one solids cooler is used to transfer combustion heat from the circulating solids to water and steam, forming one or more of steam and superheated steam;
wherein the mass flow rate of the circulating solids is in the range of from approximately 150 to 400 times the carbonaceous solids fuel feed rate to the riser;
and
wherein the transport oxy-combustor operates in the pressure range of from approximately 30 to 1000 psia.

11 more elements

A transport oxy-combustor used for the combustion of a fuel with substantially pure oxygen as an oxidant to generate a flue gas stream containing moisture, wherein when at least a portion of the moisture is separated from the flue gas stream, a net flue gas stream rich in CO2 exits the transport oxy-combustor, the transport oxy-combustor comprising:

a riser comprising a primary oxygen feed and a solids fuel stream feed;
a gas-solids separation device receiving a gas-solids mixture from the riser;
and
a downwards flow solids cooler receiving a solids stream including solids from the gas-solids separation device and providing an exit cooler solids stream;
an upwards flow solids cooler;
wherein the exit cooler solids stream travels from the downwards flow solids cooler through the upwards flow solids cooler and to a lower section of the riser, wherein in the riser, the exit cooler solids stream disperses substantially pure oxygen from the primary oxygen feed;
wherein the combustion of a solids fuel stream and dispersed substantially pure oxygen in the riser in the presence of the exit cooler solids stream moderates and controls the combustion temperature in the riser;
wherein the riser operates in the pressure range of from approximately 30 to 1000 psia;
and
wherein the mass flow rate of the circulating solids through the riser is in the range of from approximately 150 to 400 times the solids fuel stream feed rate to the riser.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/405,312Filed 26 Feb 2012 · us provisional application
Priority: 4 May 2011
Published: US 2013/0055936 A17 Mar 2013
Granted: 8 Apr 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

F23C 10/10
Characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases: the separation apparatus…
B01J 8/0055
Separating solid material from the gas/liquid stream: using cyclones
B01J 8/388
Being subject to a circulatory movement only: externally, i.e. the particles leaving the vessel and subsequently re-entering it
F22B 1/22
Methods of steam generation characterised by form of heating method: using combustion under pressure substantially exceeding atmospheric pressure