Mechanical swirler for a low-NOx, weak-swirl burner

Claim 2

A mechanical swirler, comprising: a central passage having an entrance for accepting a premixed feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said feed gas into a combustor; and an annular passage about said central passage and including one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage; and wherein said swirler does not induce recirculation in said feed gas.

Claim 3

The mechanical swirler of claim 1, wherein said flow balancing insert comprises a porous material.

Claim 4

The mechanical swirler of claim 2, wherein said flow balancing insert comprises a perforated screen.

Claim 5

The mechanical swirler of claim 2, wherein said flow balancing insert comprises wire mesh.

Claim 6

The mechanical swirler of claim 2, wherein said flow balancing insert comprises a porous ceramic material.

Claim 7

The mechanical swirler of claim 2, wherein said flow balancing insert comprises a porous polymeric material.

Claim 8

The mechanical swirler of claim 2, wherein said flow balancing insert comprises a porous metallic material.

Claim 9

The mechanical swirler of claim 1, wherein said vanes are fixed.

Claim 10

The mechanical swirler of claim 8, wherein said vanes are oriented at an angle of about 37° from the vertical.

Claim 11

The mechanical swirler of claim 1, wherein said vanes are movable.

Claim 12

The mechanical swirler of claim 1, wherein the pitch of said vanes is fixed.

Claim 13

The mechanical swirler of claim 1, wherein the pitch of said vanes is adjustable.

Claim 14

The mechanical swirler of claim 1, wherein said vanes number eight.

Claim 15

The mechanical swirler of claim 1, wherein said annular passage has no outer boundary.

Claim 16

The mechanical swirler of claim 1, further comprising a outer annular passage about said annular passage, said outer annular passage having a flow balancing insert that introduces additional pressure drop beyond that occurring in the outer annular passage without said flow balancing insert.

Claim 17

A combustor comprising: a mixer for premixing fuel and oxidant to produce a premixed feed gas; a swirler located downstream from said mixer and capable of receiving a premixed feed gas from said mixer, said swirler including a central passage having an entrance for accepting a portion of said feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said portion of said feed gas into a combustion zone, and an annular passage about said central passage having an entrance for accepting a second portion of said feed gas, one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage and an exit aligned to direct said second portion of said feed gas into the combustion zone, and wherein said swirler does not induce recirculation in said feed gas; and wherein said combustion zone is capable of supporting combustion of said premixed feed gas.

Claim 18

A combustor comprising: a mixer for premixing fuel and oxidant to produce a premixed feed gas; a swirler located downstream from said mixer and capable of receiving a premixed feed gas from said mixer, said swirler including a central passage having an entrance for accepting a portion of said feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said portion of said feed gas into a combustion zone, and an annular passage about said central passage having an entrance for accepting a second portion of said feed gas, one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage and an exit aligned to direct said second portion of said feed gas into the combustion zone, and wherein said swirler does not induce recirculation in said feed gas; and wherein said combustion zone is capable of supporting combustion of said premixed feed gas.

Claim 19

The combustor of claim 16, further comprising an exit tube disposed between the exits of said central and annular passages and said combustion zone.

Claim 20

The combustor of claim 17, wherein said combustion zone is above said exit tube.

Claim 21

The combustor of claim 17, wherein said combustion zone is within said exit tube.

Claim 22

The combustor of claim 16, wherein passage of portions of said feed gas through said central passage and said annular passage imparts a weak swirl to said fuel gas downstream of said swirler.

Claim 23

The combustor of claim 20, wherein said weak swirl is characterized by a vane swirl number between about 0.25 and 0.60.

Claim 24

The combustor of claim 20, wherein said weak swirl is characterized by a vane swirl number between about 0.27 and 0.58.

Claim 25

The combustor of claim 22, wherein said weak swirl is characterized by a vane swirl number between about 0.35 and 0.55.

Claim 26

The combustor of claim 23, wherein said weak swirl is characterized by a vane swirl number of about 0.48.

Claim 27

The combustor of claim 16, wherein said flow balancing insert comprises a porous material.

Claim 28

The combustor of claim 16, wherein said feed gas comprises natural gas and air.

Claim 29

The combustor of claim 16, wherein said feed gas comprises propane gas and air.

Claim 30

The combustor of claim 16, wherein aid feed gas comprises a pre-vaporized liquid fuel and air.

Claim 31

The combustor of claim 16, wherein said feed gas is lean.

Claim 32

The combustor of claim 16, wherein heat generated from combustion in said combustion zone is transferred to a liquid through a heat exchanger.

Claim 33

The combustor of claim 16, further comprising a turbine through which combustion products from said combustion zone are exhausted in order to generate electricity.

Claim 36

The method of claim 32, wherein said fuel is natural gas and said oxidant is air.

Claim 37

The method of claim 32, wherein said fuel is propane gas and said oxidant is air.

Claim 38

The method of claim 32, wherein said flow balancing insert is a porous material.

Claim 39

A burner, comprising: a combustion zone; a pilot mounted adjacent to said combustion zone, including, a mixer for premixing fuel and oxidant to produce a feed gas; a mechanical swirler located downstream from said mixer and capable of receiving a premixed feed gas from said mixer, said swirler including a central passage having an entrance for accepting a portion of said feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said portion of said feed gas into a second combustion zone, and an annular passage about said central passage having an entrance for accepting a second portion of said feed gas, one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage and an exit aligned to direct said second portion of said feed gas into the second combustion zone, wherein said swirler does not induce recirculation in said feed gas, and wherein said second combustion zone is capable of supporting combustion of said premixed feed gas; and wherein said pilot is capable of igniting a fuel mixture provided to said combustion zone.

Claim 40

A burner, comprising: a combustion zone; a pilot mounted adjacent to said combustion zone, including, a mixer for premixing fuel and oxidant to produce a feed gas; a mechanical swirler located downstream from said mixer and capable of receiving a premixed feed gas from said mixer, said swirler including a central passage having an entrance for accepting a portion of said feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said portion of said feed gas into a second combustion zone, and an annular passage about said central passage having an entrance for accepting a second portion of said feed gas, one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage and an exit aligned to direct said second portion of said feed gas into the second combustion zone, wherein said swirler does not induce recirculation in said feed gas, and wherein said second combustion zone is capable of supporting combustion of said premixed feed gas; and wherein said pilot is capable of igniting a fuel mixture provided to said combustion zone.