DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
This action is responsive to Applicant’s amendment and remarks filed in reply to the non-final Office action mailed June 26, 2026. Claims 8, 15, and 22 have been amended. Claims 1-7, 11, and 18 remain canceled. Claims 8-10, 12-17, and 19-23 are pending and stand under examination.
Claim Interpretation
Claims 8-10, 12-17, and 19-23 have been reviewed in accordance with 35 U.S.C. 112(f) and MPEP § 2181. No limitation of any of these claims uses the term “means,” and no limitation uses a generic placeholder coupled with functional language without reciting sufficient structure to perform the recited function. Accordingly, no claim limitation is interpreted under 35 U.S.C. 112(f).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claims 8-10, 12-14, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Low et al. (US 5,651,270) in view of Minton et al. (US 2006/0242969 A1), and further in view of Briglia et al. (US 9,950,274 B2).
In regard to claim 8, Low teaches a hybrid core-in-shell heat exchanger (shell 40 with cores 42, 44, 46) comprising:
a vessel (40) including an interior portion (inside of 40) configured to receive a liquid refrigerant (propane flashed through valve 34 and collected at level 52) (col. 3, ln. 28-43; figs. 1, 2);
a first exchanger having a first exchanger configuration (core 44) arranged in the liquid refrigerant (54) of the interior portion of the vessel (thermosiphon-circulated propane contacting the cores), the first exchanger being a brazed aluminum heat exchanger (BAHX) (brazed-aluminum-plate-fin core 44) comprising a first inlet receiving a first stream (ethylene stream 31) of a first parameter (100.4° F.; 270 psia) and a first outlet (discharging stream 33), the first inlet and the first outlet defining a first flow path through the BAHX for the first stream (31 through core 44 to 33) (col. 3, ln. 5-13; col. 3, ln. 43-51; col. 7, ln. 59-62; Table, cols. 5-6; col. 10, ln. 4-15; figs. 1, 2); and
a second exchanger having a second exchanger configuration (core 42) arranged in the liquid refrigerant of the interior portion of the vessel (thermosiphon-circulated propane contacting the cores) comprising a second inlet receiving a second stream (natural gas feed stream 20) and a second outlet (discharging stream 21), the second inlet and the second outlet defining a second flow path through the exchanger for the second stream (20 through core 42 to 21), wherein the second flow path is separate from the first flow path (discrete cores 42, 44; separate stream pairs 20/21 and 31/33), wherein the first stream and the second stream are fluidically isolated from each other within the interior portion of the vessel (4) while in temperature communication with the liquid refrigerant of the interior portion of the vessel (indirect heat exchange with the common propane pool, without commingling) (col. 3, ln. 43-51; col. 6, ln. 1-6; claim 5; Table, cols. 5-6; col. 10, ln. 4-15; figs. 1, 2).
Low does not explicitly teach the second exchanger being a tube bundle exchanger.
However, Minton teaches a heat exchanger (10) comprising a vessel (12) having an interior portion in which first and second exchangers (tube bundles 18) are arranged for indirect heat exchange with a common fluid, and teaches that either or both of the first and second heat exchangers may be a shell and tube heat exchanger, a core-in-kettle heat exchanger, a plate fin heat exchanger, a plate type heat exchanger, or multiple tube bundles in a shell heat exchanger, any such exchanger being suitable (¶¶ 0014-0015; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the core-in-shell heat exchanger of Low to include, as the exchanger receiving the second stream, a tube bundle exchanger disposed in the shell interior in place of a plate-fin core as taught by Minton, in order to provide a heat exchanger configuration selected from among the shell and tube, core-in-kettle, plate fin, plate type, and multiple-tube-bundle-in-a-shell configurations that Minton identifies as suitable for an exchanger immersed in a common refrigerant (¶ 0014). One of ordinary skill would have been motivated to make this modification because the cores of Low are separate exchangers each serving a different process stream at a different composition and pressure, the feed gas stream at 595 psia, the ethylene stream at 270 psia, and the methane-rich stream at 567 psia (col. 3, ln. 43-51; Table, cols. 5-6), so that matching the exchanger configuration to the stream served is a predictable exercise of ordinary design skill. See KSR, 550 U.S. 398; MPEP § 2143(I)(B).
The modified Low does not explicitly teach that the second stream has a mercury content greater than 0.01 µg/Nm3.
However, Briglia teaches that mercury in a stream processed by a brazed aluminum exchanger amalgamates with the aluminum and pierces the exchanger by liquid metal embrittlement, and that solidified mercury causes plugging and embrittlement of the aluminum during shutdown (col. 1, ln. 36-45). Briglia teaches that a brazed aluminum design is inoperative for the part of the duty colder than -38.6° C., that a typical mercury concentration would be 0.35 µg/Nm3 of gas at 22 bar absolute, and that the approach for that duty is to change the material and the type of exchanger, stainless steel being suitable and a shell and tube exchanger being well suited (col. 2, ln. 36-56). In the working embodiment the mercury-bearing gas (13) is routed to a second exchanger (35), which may be a shell and tube exchanger of a metal other than aluminum, rather than to the brazed aluminum plate-fin exchanger (9), and the mercury is deposited in solid form in the second exchanger (col. 8, ln. 31-50; figs. 4, 5). Briglia discloses working mercury contents of 3 µg/Nm3, 0.5 µg/Nm3, and 0.03 µg/Nm3 in the respective flows (Table 1, col. 7), and claims a flow containing at least 0.2 µg/Nm3 mercury cooled in a second exchanger of stainless steel, copper, nickel, tantalum, or an alloy thereof that is a shell and tube exchanger (col. 9, ln. 36-51; col. 10, ln. 28-55).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the core-in-shell heat exchanger of Low and Minton to include, as the second stream conducted through the tube bundle exchanger, a stream having a mercury content greater than 0.01 µg/Nm3 routed to a tube and shell exchanger of a non-aluminum material rather than to a brazed aluminum exchanger as taught by Briglia, in order to avoid the liquid metal embrittlement, amalgam corrosion, and solid mercury deposition and plugging that Briglia teaches attend the passage of a mercury-bearing stream through a brazed aluminum exchanger (col. 1, ln. 36-45; col. 2, ln. 36-56). One of ordinary skill would have been motivated to make this modification because the stream conducted through core 42 of Low is a natural gas feed stream (col. 3, ln. 43-51; col. 6, ln. 1-6; claim 5), which is the stream in a liquefaction train that carries mercury, and because Low already provides discrete, fluidically isolated flow paths through separate cores sharing one propane pool (col. 10, ln. 4-15; figs. 1, 2), so that assigning the mercury-bearing stream to the non-aluminum path while retaining the brazed aluminum core for the mercury-free refrigerant stream obtains the protection Briglia teaches without disturbing the common refrigerant duty of the shell. See MPEP § 2143(I)(C).
In regard to claim 9, Low teaches the hybrid core-in-shell heat exchanger of claim 8, further comprising a third exchanger having a third exchanger configuration (core 46) arranged in the interior portion (third core disposed in shell 40 in the propane pool), the third exchanger comprising an inlet receiving a third stream (methane-rich stream 41), the third stream being fluidically isolated from the first stream and the second stream (41 through core 46 to 43, without commingling with 20 or 31) (col. 3, ln. 43-51; col. 10, ln. 4-15; Table, cols. 5-6; figs. 1, 2).
In regard to claim 10, the modified Low teaches the hybrid core-in-shell heat exchanger of claim 9, but does not explicitly teach that the third exchanger configuration is distinct from the first and second exchanger configurations.
However, Minton teaches that printed circuit heat exchangers (etched and diffusion-bonded plate stacks) are extremely compact, high efficiency exchangers that readily tolerate high pressure and possess extreme temperature capabilities (¶ 0015), and teaches that the exchangers arranged in a common vessel interior may each take a different one of the recited configurations (¶ 0014; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the core-in-shell heat exchanger of Low to include, as the third exchanger, a printed circuit heat exchanger distinct from the brazed aluminum heat exchanger and from the tube bundle exchanger as taught by Minton, in order to obtain the extremely compact, high efficiency construction that readily tolerates high pressure and possesses extreme temperature capabilities (¶ 0015). One of ordinary skill would have been motivated to make this modification because the third stream of Low is a methane-rich refrigerant stream at 567 psia and a composition distinct from the first and second streams (col. 3, ln. 43-51; Table, cols. 5-6), so that selecting a third, distinct exchanger configuration suited to those conditions is a predictable exercise of ordinary design skill. See KSR, 550 U.S. 398; MPEP § 2143(I)(B).
In regard to claim 12, Low teaches the hybrid core-in-shell heat exchanger of claim 8, further comprising an amount of liquid refrigerant (propane pool) contained in the interior portion of the vessel (40), the amount of liquid refrigerant having a surface portion (minimum functional level 52; normal operating level 53), wherein at least one of the first and second exchangers (cores 42, 44) includes a section that projects above the surface portion (space above cores 42, 44, 46 forming liquid/vapor disengaging zone 58) (col. 4, ln. 1-10; figs. 1, 2).
In regard to claim 13, Low teaches the hybrid core-in-shell heat exchanger of claim 12, wherein the section of the one of the first and second exchangers (cores 42, 44) projects at least 4-inches (10.1 cm) above the surface portion (the liquid level varies in normal operation between the normal operating level 53 and the minimum functional level 52, the surge volume being sized for a fluctuation of from about four inches to about eight inches, while the space above the cores forms disengaging zone 58) (col. 2, ln. 48-54; col. 3, ln. 61-66; col. 4, ln. 1-10; col. 7, ln. 50-52; fig. 2). In the alternative, the extent to which a core section projects above the liquid surface is adjusted by the quantity of refrigerant held in the shell and is a result-effective variable governing the division of core surface between the boiling liquid refrigerant and the vapor space; absent a showing of unexpected results the claimed dimension is not critical, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to optimize that projection by routine experimentation to obtain the desired heat transfer balance. See In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); In re Boesch, 205 USPQ 215 (CCPA 1980); MPEP § 2144.05(II)..
In regard to claim 14, Low teaches the hybrid core-in-shell heat exchanger of claim 8, wherein the hybrid core-in-shell heat exchanger forms part of a liquid natural gas (LNG) production (shell 40 serving the high-stage propane duty of a plant producing 1.1 million metric tonnes of LNG per annum from a dry natural gas feed) (col. 6, ln. 1-6; claim 5; fig. 1).
In regard to claim 22, Low teaches the hybrid core-in-shell heat exchanger of claim 8, wherein the first parameter of the first stream (ethylene stream 31 at 100.4° F., 270 psia) and a second parameter of the second stream (natural gas feed stream 20 at 100.4° F., 595 psia) each comprises a temperature or a pressure (Table, cols. 5-6; fig. 1).
Claims 15-17, 19-21, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Low et al. (US 5,651,270) in view of Eaton et al. (US 2006/0086140 A1), in view of Minton et al. (US 2006/0242969 A1), and further in view of Briglia et al. (US 9,950,274 B2).
In regard to claim 15, Low teaches a system (cascade refrigeration system of fig. 1) comprising a hybrid core-in-shell heat exchanger as follows:
a hybrid core-in-shell heat exchanger (shell 40 with cores 42, 44, 46), the hybrid core-in-shell heat exchanger comprising:
a vessel (40) including an interior portion configured to receive a liquid refrigerant (propane flashed through valve 34 and collected at level 52) (col. 3, ln. 28-43; figs. 1, 2);
a first exchanger having a first exchanger configuration (core 44) arranged in the liquid refrigerant of the interior portion of the vessel (thermosiphon-circulated propane contacting the cores), the first exchanger being a brazed aluminum heat exchanger (BAHX) (brazed-aluminum-plate-fin core 44) comprising a first inlet receiving a first stream (ethylene stream 31) of a first parameter (100.4° F.; 270 psia) and a first outlet (discharging stream 33), the first inlet and the first outlet defining a first flow path through the BAHX for the first stream (31 through core 44 to 33) (col. 3, ln. 5-13; col. 3, ln. 43-51; col. 7, ln. 59-62; Table, cols. 5-6; col. 10, ln. 4-15; figs. 1, 2); and
a second exchanger having a second exchanger configuration (core 42) arranged in the liquid refrigerant of the interior portion (thermosiphon-circulated propane contacting the cores) comprising a second inlet receiving a second stream (natural gas feed stream 20) and a second outlet (discharging stream 21), the second inlet and the second outlet defining a second flow path through the exchanger for the second stream (20 through core 42 to 21), wherein the second flow path is separate from the first flow path (discrete cores 42, 44; separate stream pairs 20/21 and 31/33), wherein the first stream and the second stream are fluidically isolated from each other within the interior portion of the vessel while in temperature communication with the liquid refrigerant of the interior portion of the vessel (indirect heat exchange with the common propane pool, without commingling) (col. 3, ln. 43-51; col. 6, ln. 1-6; Table, cols. 5-6; col. 10, ln. 4-15; figs. 1, 2).
Low teaches a multistage compressor (10) in the refrigerant circuit (col. 3, ln. 28-33; fig. 1), but does not explicitly teach a compressor that discharges natural gas, a cooler receiving natural gas from that compressor, or the hybrid core-in-shell heat exchanger being connected to that cooler.
However, Eaton teaches a cascaded natural gas liquefaction system comprising a compressor (methane compressor 583) and a cooler (586) receiving natural gas from that compressor, in which a compressed open methane cycle gas stream, being a predominantly methane natural gas stream originating from the processed natural gas feed stream, is discharged from a methane compressor (583) through a conduit (650) to a cooler (586) and is routed from the cooler through a conduit (652) into a high-stage propane chiller (502) containing three discrete indirect heat exchange means (504, 506, 508) immersed in a common flashed-propane pool (¶¶ 0050, 0061, 0074; fig. 10).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the cascade refrigeration system of Low to include a compressor (583) discharging a natural gas stream, a cooler (586) receiving that natural gas from the compressor, and a connection from that cooler to the refrigerant-containing core-in-shell heat exchanger, as taught by Eaton, in order to cool the compressed open methane cycle gas stream before it enters the chiller so that it may be combined with the processed natural gas feed stream and liquefied (¶¶ 0061, 0074; fig. 10). One of ordinary skill would have been motivated to make this modification because shell 40 of Low already receives a natural gas feed stream (20) and a recycle methane-rich stream (41) for cooling against a common propane pool (col. 3, ln. 43-51; Table, cols. 5-6), so that supplying one of those streams from a compressor through a cooler is a conventional arrangement of the same cascade train.
The modified does not explicitly teach the second exchanger being a tube bundle exchanger.
However, Minton teaches a heat exchanger (10) comprising a vessel (12) having an interior portion in which first and second exchangers (tube bundles 18) are arranged for indirect heat exchange with a common fluid, and teaches that either or both of the first and second heat exchangers may be a shell and tube heat exchanger, a core-in-kettle heat exchanger, a plate fin heat exchanger, a plate type heat exchanger, or multiple tube bundles in a shell heat exchanger, any such exchanger being suitable (¶¶ 0014-0015; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Low and Eaton to include, as the exchanger receiving the second stream, a tube bundle exchanger disposed in the shell interior in place of a plate-fin core as taught by Minton, in order to provide a heat exchanger configuration selected from among the shell and tube, core-in-kettle, plate fin, plate type, and multiple-tube-bundle-in-a-shell configurations that Minton identifies as suitable for an exchanger immersed in a common refrigerant (¶ 0014).
The modified Low does not explicitly teach that the second stream has a mercury content greater than 0.01 µg/Nm3.
However, Briglia teaches that mercury in a stream processed by a brazed aluminum exchanger amalgamates with the aluminum and pierces the exchanger by liquid metal embrittlement, and that solidified mercury causes plugging and embrittlement of the aluminum during shutdown (col. 1, ln. 36-45). Briglia teaches that a brazed aluminum design is inoperative for the part of the duty colder than -38.6° C., that a typical mercury concentration would be 0.35 µg/Nm3 of gas at 22 bar absolute, and that the approach for that duty is to change the material and the type of exchanger, stainless steel being suitable and a shell and tube exchanger being well suited (col. 2, ln. 36-56). In the working embodiment the mercury-bearing gas (13) is routed to a second exchanger (35), which may be a shell and tube exchanger of a metal other than aluminum, rather than to the brazed aluminum plate-fin exchanger (9), and the mercury is deposited in solid form in the second exchanger (col. 8, ln. 31-50; figs. 4, 5). Briglia discloses working mercury contents of 3 µg/Nm3, 0.5 µg/Nm3, and 0.03 µg/Nm3 in the respective flows (Table 1, col. 7), and claims a flow containing at least 0.2 µg/Nm3 mercury cooled in a second exchanger of stainless steel, copper, nickel, tantalum, or an alloy thereof that is a shell and tube exchanger (col. 9, ln. 36-51; col. 10, ln. 28-55).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Low, Eaton, and Minton to include, as the second stream conducted through the tube bundle exchanger, a stream having a mercury content greater than 0.01 µg/Nm3 routed to a tube and shell exchanger of a non-aluminum material rather than to a brazed aluminum exchanger as taught by Briglia, in order to avoid the liquid metal embrittlement, amalgam corrosion, and solid mercury deposition and plugging that Briglia teaches attend the passage of a mercury-bearing stream through a brazed aluminum exchanger (col. 1, ln. 36-45; col. 2, ln. 36-56).
In regard to claim 16, Low teaches the system of claim 15, wherein the hybrid core-in-shell heat exchanger further comprises a third exchanger having a third exchanger configuration (core 46) arranged in the interior portion (third core disposed in shell 40 in the propane pool), the third exchanger comprising an inlet receiving a third stream (methane-rich stream 41), the third stream being fluidically isolated from the first stream and the second stream (41 through core 46 to 43, without commingling with 20 or 31) (col. 3, ln. 43-51; col. 10, ln. 4-15; Table, cols. 5-6; figs. 1, 2).
In regard to claim 17, the modified Low teaches the system of claim 16. Low does not explicitly teach that the third exchanger configuration is distinct from the first and second exchanger configurations.
However, Minton teaches that printed circuit heat exchangers (etched and diffusion-bonded plate stacks) are extremely compact, high efficiency exchangers that readily tolerate high pressure and possess extreme temperature capabilities (¶ 0015), and teaches that the exchangers arranged in a common vessel interior may each take a different one of the recited configurations (¶ 0014; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Low and Eaton to include, as the third exchanger, a printed circuit heat exchanger distinct from the brazed aluminum heat exchanger and from the tube bundle exchanger as taught by Minton, in order to obtain the extremely compact, high efficiency construction that readily tolerates high pressure and possesses extreme temperature capabilities (¶ 0015). One of ordinary skill would have been motivated to make this modification because the third stream of Low is a methane-rich refrigerant stream at 567 psia and a composition distinct from the first and second streams (col. 3, ln. 43-51; Table, cols. 5-6), so that selecting a third, distinct exchanger configuration suited to those conditions is a predictable exercise of ordinary design skill. See KSR, 550 U.S. 398; MPEP § 2143(I)(B).
In regard to claim 19, Low teaches the system of claim 15, wherein the hybrid core-in-shell heat exchanger further comprises an amount of liquid refrigerant (propane pool) contained in the interior portion of the vessel (40), the amount of liquid refrigerant having a surface portion (minimum functional level 52; normal operating level 53), wherein at least one of the first and second exchangers (cores 42, 44) includes a section that projects above the surface portion (space above cores 42, 44, 46 forming liquid/vapor disengaging zone 58) (col. 4, ln. 1-10; figs. 1, 2).
In regard to claim 20, Low teaches the system of claim 19, wherein the section of the one of the first and second exchangers (cores 42, 44) projects at least 4-inches (10.1 cm) above the surface portion (the liquid level varies in normal operation between the normal operating level 53 and the minimum functional level 52, the surge volume being sized for a fluctuation of from about four inches to about eight inches, while the space above the cores forms disengaging zone 58) (col. 2, ln. 48-54; col. 3, ln. 61-66; col. 4, ln. 1-10; col. 7, ln. 50-52; fig. 2). In the alternative, the extent to which a core section projects above the liquid surface is adjusted by the quantity of refrigerant held in the shell and is a result-effective variable governing the division of core surface between the boiling liquid refrigerant and the vapor space; absent a showing of unexpected results the claimed dimension is not critical, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to optimize that projection by routine experimentation to obtain the desired heat transfer balance. See In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); In re Boesch, 205 USPQ 215 (CCPA 1980); MPEP § 2144.05(II).
In regard to claim 21, Low teaches the system of claim 15, wherein the hybrid core-in-shell heat exchanger forms part of a liquid natural gas (LNG) production (shell 40 serving the high-stage propane duty of a plant producing 1.1 million metric tonnes of LNG per annum from a dry natural gas feed) (col. 6, ln. 1-6; claim 5; fig. 1).
In regard to claim 23, Low teaches the system of claim 15, wherein the first parameter of the first stream (ethylene stream 31 at 100.4° F., 270 psia) and a second parameter of the second stream (natural gas feed stream 20 at 100.4° F., 595 psia) each comprises a temperature or a pressure (Table, cols. 5-6; fig. 1).
Response to Arguments
Applicant’s arguments with respect to the amended claims have been considered but are moot in view of the new ground(s) of rejection above, unless otherwise noted below.
Applicant argues that the cited combination fails to teach a first inlet and a first outlet defining a first flow path through a BAHX for a first stream and a second inlet and a second outlet defining a separate second flow path through a tube bundle exchanger for a second stream.
This argument is not persuasive. The separate flow paths are taught by the primary references, not by Briglia. Low discloses three discrete plate-fin cores 42, 44, and 46 disposed within a single shell 40, and the Table of Low identifies inlet streams 20, 31, and 41 against the corresponding outlet streams 21, 33, and 43, so that each core defines a flow path from an inlet that admits its stream to an outlet that discharges it, separate from the flow path of every other core (col. 3, ln. 43-51; Table, cols. 5-6). Claim 14 of Low recites the point expressly: the high-stage shell contains a first, a second, and a third plate-fin-core, with the feed stream passed through the first plate-fin-core, ethylene refrigerant through the second, and methane refrigerant through the third, each in indirect heat exchange with the same first mixture of gas and liquid (col. 10, ln. 4-15). Claim 3 of Low likewise recites that the cores comprise brazed-aluminum-plate-fin cores and that the elongated high-stage heat exchange shell contains a plurality of said cores (col. 7, ln. 59-62).
Eaton discloses the same arrangement. Core-in-kettle exchanger 200 has three separate cores 204, 206, and 208 disposed side-by-side in a single shell 202, allowing simultaneous indirect heat transfer between the shell-side fluid A and three separate core-side fluids B1, B2, and B3 (¶ 0045; figs. 6, 7). Each core has a core-side fluid inlet 32 coupled to an inlet header 34 and a core-side fluid outlet 36 coupled to an outlet header 38 (¶ 0038; fig. 1), and the core-side passageways 42 are fluidly isolated from the internal volume 24 of the shell (¶ 0039). In the facility of FIG. 10 this structure is realized as high-stage propane chiller 502, in which gaseous methane refrigerant 652, natural gas feed 600, and gaseous ethylene refrigerant 702 are respectively cooled via indirect heat exchange means 504, 506, and 508 and produced as separate cooled streams 654, 602, and 704 (¶ 0061). Applicant’s own remarks acknowledge that Low describes multiple heat exchanger cores 42, 44, and 46 positioned within a common shell containing liquid refrigerant. Further, the newly added flow path language recites no structure beyond the discrete inlet, the discrete outlet, and the fluid isolation already of record.
Applicant argues that Briglia processes the mercury-containing flow sequentially, cooling it first in brazed aluminum exchanger 9 and thereafter directing a downstream portion of that same flow to exchanger 35, and therefore does not teach a separate second flow path for a second stream.
This argument is not persuasive. Applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In this case, Briglia is not relied upon for the arrangement of two separate flow paths within a common refrigerant vessel; that arrangement is supplied by Low and by Eaton. Briglia is relied upon for the teaching that a stream whose mercury content exceeds the tolerance of aluminum is to be conducted through an exchanger of a different type and a non-aluminum material rather than through a brazed aluminum exchanger, and for its disclosure of mercury contents far in excess of the claimed threshold of 0.01 µg/Nm3. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference, but what the combined teachings would have suggested to one of ordinary skill in the art.
Applicant argues that Minton does not teach assigning a mercury-containing second stream to a separate tube bundle flow path while a different first stream passes through a BAHX.
This argument is not persuasive for the same reason. Minton is relied upon for the teaching that a tube bundle exchanger, a printed circuit heat exchanger, a core-in-kettle exchanger, a plate fin exchanger, and a plate type exchanger are recognized, suitable alternatives for an exchanger arranged within a vessel interior for indirect heat exchange with a common fluid (¶¶ 0014-0015; fig. 1). The assignment of the mercury-bearing stream to the non-aluminum path is supplied by Briglia, and the two separate paths are supplied by Low and by Eaton. It is further noted that Applicant’s own specification states that most LNG facilities employ systems to remove contaminants including mercury and mercury compounds from the natural gas stream at different points during the liquefaction process (¶ 0006), and that 5000-series aluminum alloys commonly used in brazed aluminum heat exchangers can be damaged if exposed to mercury concentration in excess of 0.01 µg/Nm3 (¶ 0063). A statement in the specification identifying matter as being within the prior art may be used against Applicant in determining patentability. See MPEP § 2129.
As set forth in the Claim Interpretation section above, claim 8 is directed to an apparatus and claim 15 to a system, and the recited mercury content of the second stream is directed to the material worked upon rather than to the structure of the claimed exchangers. See MPEP § 2115; In re Schreiber, 128 F.3d 1473, 1477 (Fed. Cir. 1997). The prior art is nonetheless shown above to teach the recited mercury content on its merits. Briglia claims a flow containing at least 0.2 µg/Nm3 mercury (col. 9, ln. 36-51), identifies 0.35 µg/Nm3 of gas at 22 bar absolute as a typical mercury concentration (col. 2, ln. 45-46), and reports working mercury contents of 3 µg/Nm3 and 0.5 µg/Nm3 in the flows cooled in its first and second exchangers (Table 1, col. 7). Each of these values is between twenty and three hundred times the claimed threshold of 0.01 µg/Nm3.
Conclusion
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/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
