DETAILED ACTION
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier.
Such claim limitation(s) is/are:
mixing element adapted for mixing the bleed air and the flue gas, as recited in claim 7.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
The corresponding structures described in the specifications is/are:
mixing element [Wingdings font/0xE0] chevron mixer 56, as shown in Fig. 7
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 31 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 31 recites the limitation "tertiary air damper stopper". There is insufficient antecedent basis for this limitation in the claim.
Claim Rejections – 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1, 4, 5, 10, 12-19, 21-23, 32, 34-36 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stephens (US 20170283713 A1) in view of Michelson (US 4629413 A).
Regarding claim 1, Stephens discloses a burner device for combusting a fuel in a furnace enclosure, the burner device comprising:
a primary air chamber (Fig. 1; 26) configured to receive a primary air and a flue gas to form an air-flue gas mixture in the primary air chamber;
a staged air chamber (32) configured to receive a staged air;
a burner tube (12) having a first tube end (160) and a second tube end, the first tube end configured to receive the air-flue gas mixture from the primary air chamber and a fuel to form a fuel-air-flue gas mixture in the burner tube (paras. 43, 45);
a burner tip (20) downstream of the second tube end, the burner tip having center orifices and side orifices (Fig. 8 and para. 82), the burner tip configured to discharge a first portion of the fuel-air-flue gas mixture into a first combustion zone in the furnace enclosure via the center orifices and a second portion of the fuel-air-flue gas mixture into a second combustion zone in the furnace enclosure via the side orifices, respectively (para. 76);
one or more staged air ports (Fig. 2; 30) configured to discharge the staged air from the staged air chamber (32) into a third combustion zone in the furnace enclosure; and
a tile (Fig. 1; 22) adjacent to the burner tip configured to form a tile-burner tip gap (Fig. 8; 70) between the burner tip and the tile (para. 93).
Stephens fails to disclose:
a tertiary air chamber configured to receive a tertiary air; and
the tile-burner tip gap being in fluid communication with the tertiary air chamber and capable of discharging the tertiary air into the second combustion zone.
Michelson teaches a burner device for combusting a fuel in a furnace enclosure, comprising:
a tertiary air chamber configured to receive a tertiary air (Fig. 3; 21); and
a tile (12) -burner tip (11) gap being in fluid communication with the tertiary air chamber and capable of discharging the tertiary air into the second combustion zone.
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Stephens to include a tertiary air chamber configured to receive a tertiary air; and where the tile-burner tip gap is in fluid communication with the tertiary air chamber and capable of discharging the tertiary air into the second combustion zone.
The motivation to combine is to provide fine adjustment of the oxidant per stoichiometric requirements (see Michelson, in col. 8, lines 30-44).
Regarding claim 4, modified Stephens discloses the burner device of claim 1, wherein: the burner device further comprises a steam supply tube capable of supplying a steam into the burner tube such that the fuel-air-flue gas mixture comprises steam (Stephens; para. 58).
Regarding claim 5, modified Stephens discloses the burner device of claim 4, wherein the steam supply tube (Stephens; 15) has an end inserted into or just upstream of the first tube end of the burner tube (Stephens; Fig. 1).
Regarding claim 10, modified Stephens discloses the burner device of claim 1, wherein the one or more staged air ports extends through a furnace floor, or a furnace roof, or a furnace wall of the furnace enclosure (Stephens; para. 44).
Regarding claim 12, modified Stephens discloses the burner device of claim 1, further comprising at least one of the following: a staged air inlet comprising a staged air inlet damper (Stephens; 34) and in fluid communication with the heat exchanger and/or the staged air chamber; and a primary air inlet comprising a primary air inlet damper (Stephens; 37b) and coupled to the primary air chamber.
Regarding claim 13, modified Stephens discloses a process for combusting a fuel using the burner device of claim 1.
Regarding claim 14, modified Stephens discloses a furnace including the burner device of claim 1, wherein the furnace is a steam cracking furnace, a steam-hydrocarbon reforming furnace, or a steam boiler furnace (Stephens; para. 53).
Regarding claim 15, modified Stephens discloses the furnace of claim 14, which is the steam cracking furnace comprising a radiant section including a radiant tube and the burner device, wherein the radiant tube is in proximity to the burner device, such that the thermal energy released by combusting the fuel by the burner device is capable of heating the radiant tube (Stephens; para. 100).
Regarding claim 16, modified Stephens discloses the furnace of claim 15, further comprising more than one of the burner device and more than one of the radiant tube (Stephens; paras. 100 and 109).
Regarding claim 17, modified Stephens discloses the furnace of claim 15, wherein a portion of the burner device extends through a floor of the furnace enclosure (Stephens; para. 43).
Regarding claim 18, modified Stephens discloses the furnace of claim 14, which is a hydrocarbon-steam reforming furnace, wherein a portion of the burner device extends through a side wall or a roof of a housing of the furnace (Stephens; paras. 42, 100).
Regarding claim 19, modified Stephens discloses (see rejection of claim 1 for citations) a process for combusting a fuel in a furnace comprising a furnace enclosure and a burner device, wherein the burner device comprises a primary air chamber, a staged air chamber, a tertiary air chamber, a burner tube having a first tube end and a second tube end, and a burner tip having center orifices and side orifices coupled to the second tube end, a tile in proximity to the burner tip defining a tile-burner tip gap between the tile and the burner tip, the first tube end is in fluid communication with the primary air chamber, the furnace enclosure is in fluid communication with the staged air chamber via one or more staged air ports, the furnace enclosure is in fluid communication with the tertiary air chamber via the tile-burner tip gap, and the process comprises: supplying a primary air and a flue gas into the primary air chamber to form an air-flue gas mixture in the primary air chamber; supplying a staged air into the staged air chamber; supplying a tertiary air into the tertiary air chamber; supplying the fuel into the first tube end; receiving the air-flue gas mixture via the first tube end into the burner tube to mix with fuel to form a fuel-air-flue gas mixture in the burner tube; discharging a first portion of the fuel-air-flue gas mixture into a first combustion zone in the furnace enclosure via the center orifices of the burner tip; discharging a second portion of the fuel-air-flue gas mixture into a second combustion zone in the furnace enclosure via the side orifices of the burner tip; discharging the tertiary air into the second combustion zone via the tile-burner tip gap; discharging the staged air from the staged air chamber into a third combustion zone in the furnace enclosure via the one or more staged air ports; and combusting the fuel in at least one of the first combustion zone, the second combustion zone, and the third combustion zone.
Regarding claim 21, modified Stephens discloses the process of claim 19, wherein: the burner tube comprises a venturi segment, and the venturi segment includes a diverging outlet with an inner fluid channel that has an increasing size along a flow direction of the fuel-air-flue gas mixture in the venturi segment; and the process comprises: injecting the fuel into the first tube end as a fuel jet (see rejection of claim 3).
Regarding claim 22, modified Stephens discloses the process of claim 19, further comprising: supplying a steam into the first tube end such that the fuel-air-flue gas mixture comprises steam (see rejection of claim 4).
Regarding claim 23, modified Stephens discloses the process of claim 19, wherein at least a portion of the primary air is supplied to the primary air chamber via a primary air inlet comprising an adjustable primary air inlet damper (see rejection of claim 12).
Regarding claim 32, modified Stephens discloses the process of claim 19, wherein the fuel comprises hydrogen at a concentration of at least 90 mol%, based on the total moles in the fuel (Stephens; para. 42).
Regarding claim 34, modified Stephens discloses the process of claim 19, further comprising at least one of the following: receiving the staged air via a staged air inlet comprising a staged air inlet damper (Stephens; 34) and in fluid communication with the heat exchanger and/or the staged air chamber.
Regarding claim 35, modified Stephens discloses the process of claim 19, further comprising: reducing a flow rate of the primary air through the primary air inlet into the primary air chamber (Stephens; para. 45).
Regarding claim 36, modified Stephens discloses the process of claim 35, comprising closing the adjustable primary air inlet damper in the primary air inlet (Stephens; para. 45).
Claim(s) 2, 3, 6, 7, 9, 20, 24-27 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stephens (US 20170283713 A1) in view of Michelson (US 4629413 A), as applied to claim 1, and further in view of Kim (KR 20190006245 A).
Regarding claim 2, modified Stephens discloses the burner device of claim 1, further comprising:
a flue gas recirculation (FGR) duct (Fig. 1; 76) configured to receive the flue gas from the furnace enclosure EXCEPT:
a heat exchanger configured to (i) receive the staged air or a portion thereof; (ii) receive the flue gas or a portion thereof from the FGR duct, wherein the flue gas before entering the heat exchanger has a higher temperature than the staged air before entering the heat exchanger; (iii) exchange heat between the flue gas and the staged air; (iv) discharge a cooled flue gas into the primary air chamber; and (v) discharge a heated staged air into the staged air chamber.
Kim teaches a recuperative burner, comprising:
a heat exchanger (Fig. 2; 14) configured to (i) receive the air (13) or a portion thereof;
(ii) receive the flue gas (3) or a portion thereof from the FGR duct, wherein the flue gas before entering the heat exchanger has a higher temperature than the air before entering the heat exchanger; and
(iii) exchange heat between the flue gas and the air.
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Stephens to include a heat exchanger configured to (i) receive the staged air or a portion thereof; (ii) receive the flue gas or a portion thereof from the FGR duct, wherein the flue gas before entering the heat exchanger has a higher temperature than the staged air before entering the heat exchanger; (iii) exchange heat between the flue gas and the staged air; (iv) discharge a cooled flue gas into the primary air chamber; and (v) discharge a heated staged air into the staged air chamber.
With the modification, cool staged air from the inlet (see Fig. 1 of Stephens; 34) enters the heat exchanger and exchange heat with the hot flue gas from the flue duct (Stephens; 76), and then enters the staged air chamber (Stephens; 32) as preheated staged air. The cooled flue gas after heat exchange continues to the primary air chamber (Stephens; 26).
The motivation to combine is to improve combustion efficiency by utilizing waste heat from the flue gas to preheat the combustion air.
Regarding claim 3, modified Stephens discloses the burner device of claim 2, wherein: the burner device comprises a fuel supply tube (Stephens; 65) capable of supplying the fuel into the burner tube as a fuel jet; and
the burner tube comprises a venturi segment (Stephens; 19), and the venturi segment includes a diverging outlet with an inner fluid channel that has an increasing size along a flow direction of the fuel-air-flue gas mixture in the venturi segment (Stephens; Fig. 1).
Regarding claim 6, modified Stephens discloses the burner device of claim 2, further comprising one or more bleed air ducts (Stephens; 64 and para. 51) configured to channel a bleed air into the FGR duct at a bleed air inlet location upstream of the heat exchanger relative to a flow of the flue gas in the FGR duct.
Regarding claim 7, modified Stephens discloses the burner device of claim 6, further comprising one or more mixing elements (see elements 37, 38 and also para. 46 of Stephens) disposed in the FGR duct downstream of the bleed air inlet location, the one or more mixing elements adapted for mixing the bleed air and the flue gas, except where the mixing elements are placed upstream of the heat exchanger relative to the flow of the flue gas in the FGR duct.
However, the relative placement of the mixing elements and the heat exchanger is a matter of optimization. The mixing elements are used to mix the air and flue gases for proper combustion conditions, and the heat exchanger is designed to transfer heat from the mixture to the staged air so that the staged air can be preheated for thermal efficiency. A person skilled in the art can experiment on the location of their relative placement to maximize both factors..
Regarding claim 9, modified Stephens discloses the burner device of claim 6, wherein the one or more bleed air ducts comprises a bleed air inlet fitted with one or more machined inserts (see Fig. 4 and para. 46 of Stephens; protruding tubes 37, 38) each having a predefined opening size adapted for controlling a flow rate of the bleed air. Note: the term, “machined” is a product by process limitation, and the process of making, i.e., machining, is not given weight. See MPEP 2113.
Regarding claim 20, modified Stephens discloses the process of claim 19 (see rejection of claim 2 for citations), wherein the burner device comprises a flue gas recirculation (FGR) duct for channeling the flue gas from the furnace enclosure into the primary air chamber and a heat exchanger, the heat exchanger is configured to (i) receive the staged air or a portion thereof; (ii) receive the flue gas or a portion thereof from the FGR duct; (iii) exchange heat between the flue gas and the staged air; (iv) discharge a cooled flue gas into the primary air chamber; and (v) discharge a heated staged air into the staged air chamber; and the process comprises: receiving the flue gas from the furnace enclosure into the FGR duct; receiving the flue gas into the heat exchanger from the FGR duct; receiving the staged air into the heat exchanger, wherein the staged air has a temperature lower than the flue gas; exchanging heat between the flue gas and the staged air in the heat exchanger; discharging the cooled flue gas into the primary air chamber; and discharging a heated staged air into the staged air chamber.
Regarding claim 24, modified Stephens discloses the process of claim 20, further comprising: supplying a bleed air into the FGR duct via a bleed air duct and at a bleed air inlet location upstream of the heat exchanger relative to a flow of the flue gas in the FGR duct, wherein the bleed air constitutes at least a portion of the primary air supplied into the primary air chamber; and mixing the flue gas and the bleed air in the FGR duct via one or more mixing elements disposed in the FGR duct downstream of the bleed air inlet location and upstream of the heat exchanger relative to the flow of the flue gas in the FGR duct (see rejection of claims 6, 7).
Regarding claim 25, modified Stephens discloses the process of claim 24, further comprising: controlling a flow rate of the bleed air by using a machined metal insert having a predetermined dimension at the bleed air inlet location (see rejection of claim 9).
Regarding claim 26, modified Stephens discloses the process of claim 24, wherein the bleed air constitutes at least 80%, by volume, of the primary air supplied into the primary air chamber (this can be accomplished by adjusting the primary air damper 37b and bleed air dampers 34 of Stephens). Moreover, the precise percentage is a matter of optimizing the stoichiometric air-fuel ratio, flame temperature, and amount of emissions produced.
Regarding claim 27, modified Stephens discloses the process of claim 24, further comprising: closing the primary air inlet damper (Stephens; 37b and para. 45), such that the bleed air constitutes substantially all of the primary air supplied into the primary air chamber. Moreover, the precise percentage is a matter of optimizing the stoichiometric air-fuel ratio, flame temperature, and amount of emissions produced.
Claim(s) 29, 30, 33 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stephens (US 20170283713 A1) in view of Michelson (US 4629413 A), as applied to claim 1, and further in view of Behrendt (US 20100307428 A1).
Regarding claim 29, modified Stephens discloses the process of claim 19, except further comprising: during a first time interval, supplying the fuel into the first tube end; at the end of the first time interval, switching the fuel to an alternate fuel differing from the fuel; and during a second time interval immediately after the first time interval, supplying the alternate fuel into the first tube end.
Stephens discloses where different fuels can be used in the burner (para. 42), but does not disclose switching fuels. However, Behrendt teaches switching from one fuel to another during burner operations (para. 70), i.e., during a first time interval, supplying the fuel into the burner; at the end of the first time interval, switching the fuel to an alternate fuel differing from the fuel; and during a second time interval immediately after the first time interval, supplying the alternate fuel into the burner.
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Stephens to include the steps of: during a first time interval, supplying the fuel into the first tube end; at the end of the first time interval, switching the fuel to an alternate fuel differing from the fuel; and during a second time interval immediately after the first time interval, supplying the alternate fuel into the first tube end. The motivation to combine is so that various fuels can be used for the burner depending on the cost and availability of the fuel. The result is a burner that maintain operation even if there is a shortage of one type of fuel.
Regarding claim 30, modified Stephens discloses the process of claim 29, wherein: the fuel comprises hydrogen at a concentration of at least 80 mol%, based on the total moles in the fuel (para. 42); except the alternate fuel comprises methane at a concentration of at least 80 mol%, based on the total moles in the alternate fuel (Stephens discloses the use of methane as a fuel source along with hydrogen, but the mol % is unknown; see para. 42).
However, Official Notice is taken that natural gas, a common fuel source for burners, is known to contain at least 80 mol% methane, and it would have been obvious to a person skilled in the art at the time of effective filing of the application where natural gas having 80 mol% methane is used as the alternate fuel since natural gas is a readily available fuel.
Regarding claim 33, modified Stephens discloses the process of claim 29, wherein: the fuel comprises methane at a concentration of at least 80 mol%, based on the total moles in the fuel; and the alternate fuel comprises hydrogen at a concentration of at least 80 mol%, based on the total moles in the alternate fuel (see rejection of claim 30).
Allowable Subject Matter
Claims 8, 11, 28 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JASON LAU whose telephone number is (571)270-7644. The examiner can normally be reached Mon-Fri 8:00-5:00.
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/JASON LAU/Primary Examiner, Art Unit 3762
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