Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-15-02086/USCOURTS-ca13-15-02086-0/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 

---

United States Court of Appeals 

for the Federal Circuit ______________________ 

DAVID NETZER CONSULTING ENGINEER LLC,

Plaintiff-Appellant

v.

SHELL OIL COMPANY, SHELL CHEMICAL LP, 

SHELL OIL PRODUCTS COMPANY LLC,

Defendants-Appellees

______________________ 

2015-2086

______________________ 

Appeal from the United States District Court for the 

Southern District of Texas in No. 4:14-cv-00166, Judge 

Lynn N. Hughes.

______________________ 

Decided: May 27, 2016

______________________ 

ANTHONY MATTHEW GARZA, Charhon Callahan Robson 

& Garza, P.C., Dallas, TX, argued for plaintiff-appellant. 

Also represented by STEVEN CHASE CALLAHAN. 

KATHLEEN M. SULLIVAN, Quinn Emanuel Urquhart & 

Sullivan, LLP, New York, NY, argued for defendantsappellees. Also represented by KEVIN ALEXANDER SMITH, 

San Francisco, CA; JOSHUA L. SOHN, Washington, DC; 

CHARLES BRUCE WALKER, JR., Norton Rose Fulbright US 

LLP, Houston, TX; JAYME PARTRIDGE, Patterson & Sheridan LLP, Houston, TX.

Case: 15-2086 Document: 53-2 Page: 1 Filed: 05/27/2016
2 DAVID NETZER v. SHELL OIL COMPANY

______________________ 

Before PROST, Chief Judge, LOURIE and TARANTO,

Circuit Judges.

LOURIE, Circuit Judge. 

David Netzer Consulting Engineer LLC (“Netzer”)*

appeals from the decision of the United States District 

Court for the Southern District of Texas granting summary judgment of noninfringement of the asserted claims 

of U.S. Patent 6,677,496 (“the ’496 patent”). David Netzer 

Consulting Eng’r LLC v. Shell Oil Co., No. 4:14-cv-00166, 

ECF No. 45 (S.D. Tex. Aug. 26, 2015) (“Decision”). For the 

reasons that follow, we affirm. 

BACKGROUND

Netzer owns the ’496 patent, entitled “Process for the 

Coproduction of Benzene from Refinery Sources and 

Ethylene by Steam Cracking,” which describes a process 

for the coproduction of ethylene and purified benzene

from refinery mixtures. Claim 1, the sole independent 

claim, reads as follows:

1. A process for the coproduction of ethylene and 

purified benzene comprising:

providing a first mixture comprising benzene,

toluene, and one or more C6 to C7 nonaromatics;

separating the majority of the benzene and the 

one or more C6 to C7 non-aromatics from the 

majority of the toluene to form a second 

mixture containing at least a portion of the 

* As indicated infra, in March 2014, David Netzer 

Consulting Engineer LLC changed its name to David 

Netzer – Petrochemicals Consultant LLC.

 

Case: 15-2086 Document: 53-2 Page: 2 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 3

benzene and at least a portion of the one or 

more C6 to C7 non-aromatics, wherein the 

second mixture is substantially free of hydrocarbons having more than nine carbons;

introducing at least a portion of the second 

mixture to a cracker and thereafter cracking 

at least about 80% of the C6 to C7 nonaromatics in the portion of the second mixture that has been introduced to the cracker 

while maintaining essentially no cracking of 

benzene to produce a cracked product containing ethylene, propylene and pyrolysis

gasoline comprising olefins, di-olefins and 

benzene; and

fractionating the pyrolysis gasoline to form a 

purified benzene product comprising at least 

about 80 wt % benzene. 

’496 patent col. 7 ll. 11–32 (emphases added). 

The claimed process thus requires four steps: (1) providing a mixture containing benzene, toluene, and C6–C7

non-aromatic hydrocarbons; (2) separating most of the 

benzene and C6–C7 non-aromatic hydrocarbons from most 

of the toluene; (3) introducing the benzene-rich stream 

into a cracker, i.e., a reactor that breaks down long-chain 

hydrocarbons to short-chain hydrocarbons, and then 

cracking the C6–C7 non-aromatic hydrocarbons to produce

ethylene and pyrolysis gasoline; and (4) “fractionating the 

pyrolysis gasoline to form a purified benzene product 

comprising at least about 80 wt % of benzene” (“the fractionating step”).

On January 23, 2014, David Netzer, the sole inventor 

of the ’496 patent, assigned the patent to Netzer, a limited 

liability company newly formed under Texas law. J.A. 85 

(assignment); J.A. 81–83 (Certificate of Filing issued by 

the Secretary of State). The next day, Netzer sued Shell 

Case: 15-2086 Document: 53-2 Page: 3 Filed: 05/27/2016
4 DAVID NETZER v. SHELL OIL COMPANY

Oil Company, Shell Chemical LP, and Shell Oil Products 

Company LLC (collectively, “Shell”) in the United States

District Court for the Southern District of Texas, alleging

that Shell infringed the ’496 patent. Shortly thereafter, 

the State of Texas requested that Netzer remove the word 

“Engineer” from its name. In March 2014, Netzer

changed its name from David Netzer Consulting Engineer 

LLC to David Netzer – Petrochemicals Consultant LLC 

through a Certificate of Correction. J.A. 78–79, 87–88. 

Meanwhile, Shell answered and counterclaimed for a 

declaratory judgment of noninfringement and invalidity

in the district court.

Shell then moved for summary judgment of noninfringement. Shell argued that the term “fractionating”

should be construed to mean “conventional distillation, 

i.e., separating compounds based on difference in their 

boiling points,” which excludes extraction, i.e., separating 

compounds based on solubility differences. Shell argued

that the patentee disclaimed extraction in the specification and prosecution history. According to Shell, its

accused process does not meet the fractionating step 

because it uses extraction—more specifically, the Sulfolane process developed by Shell in the 1960s—to form a 

benzene product with 99.9% purity. Netzer responded

that “fractionating” should be construed to mean “separating a chemical mixture into fractions, no matter the 

process units used.” Examples of process units, according 

to Netzer, include distillation columns (for separating 

chemicals based on differences in boiling points), extractors (for separating chemicals based on solubility differences), and hydrotreaters (for hydrogenating unsaturated 

hydrocarbons, such as olefins). Netzer also argued that 

Shell infringes literally under either construction, and 

that Shell also infringes under the doctrine of equivalents.

The district court granted summary judgment of noninfringement. The court did not formally construe the 

claims, but, rather, implicitly agreed with Shell that 

Case: 15-2086 Document: 53-2 Page: 4 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 5

“fractionating” does not include extraction. The court 

found no literal infringement, reasoning that “Netzer’s 

method does not include extraction and does not yield 

benzene of 99.9% purity” and that “[t]o infringe, Shell 

would have to eliminate the extraction step and still 

produce benzene purified to at least 80%.” Decision at 2. 

The court also found no infringement under the doctrine 

of equivalents because Netzer is barred by “specific exclusion, prosecution-history estoppel, and prior art.” Id. at 3. 

The district court then entered final judgment in favor 

of Shell. David Netzer Consulting Eng’r LLC v. Shell Oil 

Co., No. 4:14-cv-00166, ECF No. 46 (S.D. Tex. Aug. 26, 

2015). Netzer timely appealed to this court. However, 

because Shell’s counterclaims remained pending in the 

district court, this court granted the parties’ joint motion 

for a limited remand. On that limited remand, the district court dismissed Shell’s declaratory judgment counterclaims without prejudice and then entered an amended

final judgment, thus disposing of all claims and counterclaims. David Netzer Consulting Eng’r LLC v. Shell Oil 

Co., No. 4:14-cv-00166, ECF No. 56 (S.D. Tex. Mar. 31, 

2016). Netzer then filed a new notice of appeal, and its

appeal was reinstated in this court. We have jurisdiction 

under 28 U.S.C. § 1295(a)(1).

DISCUSSION

I 

Before we reach the merits of Netzer’s appeal, Netzer 

asks us to confirm that it has standing to maintain this

action. According to Netzer, on January 24, 2014, at the 

inception of the lawsuit, an entity known as David Netzer 

Consulting Engineer LLC held enforceable title to the 

’496 patent pursuant to the January 23, 2014 assignment, 

and thus had standing to sue. Netzer argues that the 

March 2014 name change did not retroactively invalidate

the January 2014 assignment under Texas law. The 

district court did not question Netzer’s standing.

Case: 15-2086 Document: 53-2 Page: 5 Filed: 05/27/2016
6 DAVID NETZER v. SHELL OIL COMPANY

We agree with Netzer that it has standing to bring 

and maintain this action. At the inception of the lawsuit, 

the ’496 patent was assigned to the plaintiff entity, then

named David Netzer Consulting Engineer LLC. Although 

that entity later changed its name to David Netzer – 

Petrochemicals Consultant LLC as required by Texas law, 

that name change did not undo the January 23, 2014

transfer of patent ownership. The patent was owned by 

the same company, under its new name. We therefore 

conclude that Netzer, as the owner of the ’496 patent as of 

January 24, 2014, has standing to maintain this action.

II

We turn now to the merits of Netzer’s appeal. When 

reviewing a district court’s grant of summary judgment, 

we apply the law of the regional circuit in which the 

district court sits, here, the law of the Fifth Circuit. Teva 

Pharm. Indus. Ltd. v. AstraZeneca Pharm. LP, 661 F.3d 

1378, 1381 (Fed. Cir. 2011). The Fifth Circuit reviews a 

district court’s summary judgment decision de novo, 

applying the same standard used by the district court. 

United States v. Caremark, Inc., 634 F.3d 808, 814 (5th

Cir. 2011). Summary judgment is appropriate when, 

drawing all justifiable inferences in the nonmovant’s 

favor, “there is no genuine dispute as to any material fact 

and the movant is entitled to judgment as a matter of 

law.” Fed. R. Civ. P. 56(a); Anderson v. Liberty Lobby, 

Inc., 477 U.S. 242, 247–48 (1986).

To determine infringement, a court first construes the 

scope and meaning of the asserted patent claims, and 

then compares the construed claims to the accused product or process. Absolute Software, Inc. v. Stealth Signal, 

Inc., 659 F.3d 1121, 1129 (Fed. Cir. 2011). “The proper 

construction of a patent’s claims is an issue of Federal 

Circuit law.” Id. We review a district court’s ultimate 

claim constructions de novo and any underlying factual 

determinations involving extrinsic evidence for clear 

Case: 15-2086 Document: 53-2 Page: 6 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 7

error. Teva Pharm. U.S.A., Inc. v. Sandoz, Inc., 135 S. Ct. 

831, 841–42 (2015).

Here, the district court did not make any factual findings to support any claim construction. See Appellant’s 

Br. 21. Its claim construction was implicit in its decision 

of noninfringement. Because the intrinsic record alone 

determines the proper construction in this case, we are 

able to conduct our review adequately and we do so de 

novo. See Shire Dev., LLC v. Watson Pharm., Inc., 787 

F.3d 1359, 1364, 1368 (Fed. Cir. 2015) (citing Teva, 135 S. 

Ct. at 840–42). 

Infringement is a question of fact. Absolute Software, 

659 F.3d at 1129–30. “On appeal from a grant of summary judgment of non-infringement, we determine 

whether, after resolving reasonable factual inferences in 

favor of the patentee, the district court correctly concluded that no reasonable jury could find infringement.” Id.

A. Claim Construction

The words of a claim “are generally given their ordinary and customary meaning” as understood by a person 

of ordinary skill in the art at the time of the invention. 

Phillips v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 

2005) (en banc). Because that meaning is “often not 

immediately apparent, and because patentees frequently 

use terms idiosyncratically,” the court looks to the intrinsic record, including “the words of the claims themselves, 

the remainder of the specification, [and] the prosecution 

history,” as well as to extrinsic evidence when appropriate, to construe a disputed claim term. Id. at 1314, 

1319. “[W]hile extrinsic evidence can shed useful light on 

the relevant art, we have explained that it is less significant than the intrinsic record in determining the legally 

operative meaning of claim language.” Id. at 1317 (quotation marks omitted). 

Case: 15-2086 Document: 53-2 Page: 7 Filed: 05/27/2016
8 DAVID NETZER v. SHELL OIL COMPANY

Because a patent is a fully integrated written instrument, we have long emphasized the importance of the 

specification in claim construction. Id. at 1315 (explaining that the specification “is the single best guide to the 

meaning of a disputed term”) (quoting Vitronics Corp. v. 

Conceptronic, Inc., 90 F.3d. 1576, 1582 (Fed. Cir. 1996)). 

Thus, if the specification reveals a special definition given 

to a claim term by the inventor, then the inventor’s lexicography governs, even if it differs from the term’s ordinary meaning. Id. at 1316. Likewise, if the specification 

reveals an intentional disclaimer or disavowal of claim 

scope by the inventor, then the inventor’s intention as 

expressed in the specification is regarded as dispositive. 

Id. We have found disavowal or disclaimer based on clear 

and unmistakable statement, such as “the present invention includes . . . ,” “the present invention is . . . ,” and “all 

embodiments of the present invention are . . . .” Pacing 

Techs., LLC v. Garmin Int’l, Inc., 778 F.3d 1021, 1024 

(Fed. Cir. 2015). 

Netzer argues that “fractionating” means separating a 

mixture into fractions, no matter what processes are used

to do so. According to Netzer, both the intrinsic record 

and the extrinsic evidence suggest that fractionation

includes any method of separation, not limited to distillation. Netzer contends that the patentee did not disclaim 

extraction by merely characterizing it as expensive in the 

specification. Netzer additionally argues that the claim 

only sets a lower limit on benzene purity, viz., “at least 

about 80 wt %,” and thus does not exclude extraction, 

which produces highly pure benzene. Netzer lastly argues

that “fractionating” ought to be construed to encompass 

the disclosed preferred embodiment, so as to allow the 

pyrolysis gasoline to pass through (a) more than one 

process unit (in the preferred embodiment, a hydrotreater 

and then two distillation columns), and (b) process units 

that do not separate chemicals, such as a hydrotreater.

Case: 15-2086 Document: 53-2 Page: 8 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 9

Shell responds that “fractionating” should be construed here to mean separating compounds based on 

differences in boiling points, not generic “separating” by 

any means. Shell argues that the intrinsic record compels 

that construction, which cannot be altered by conflicting 

extrinsic evidence. In particular, Shell contends that the 

patent specification uses “fractionating” or “fractionation” 

to describe separating compounds based on boiling points. 

According to Shell, the patentee also disclaimed extraction in the specification by distinguishing it from “fractionation” and by explaining that the claimed invention 

was driven by a shift in market demand that no longer 

required high purity benzene produced by extraction, such 

as by the Sulfolane process. 

We agree with Shell that the claim term “fractionating” in this patent means separating compounds based on 

differences in boiling points, i.e., distillation, which excludes extraction, such as in the Sulfolane process. The 

specification repeatedly and consistently uses “fractionating” or “fractionation” to describe separating petrochemicals based on boiling point differentials. Moreover, 

importantly, the patentee made clear and unmistakable

statements in the intrinsic record, distinguishing the 

claimed invention from and disclaiming conventional 

extraction methods that produce 99.9% pure benzene.

Specifically, the ’496 patent describes an “azeotrope” 

problem. An azeotrope is a mixture of two or more compounds that has a uniform boiling point; its components 

vaporize together as a mixture and thus cannot be easily 

separated from each other by distillation. J.A. 273. The

specification explains that certain C6–C7 non-aromatic 

hydrocarbons form azeotropes with benzene, making it 

“impossible” to separate benzene from that mixture by 

“conventional fractionation.” ’496 patent col. 2 ll. 17–20. 

The specification then discusses this issue in further 

detail and refers to the azeotrope problem as “the conventional fractionation issue.” Id. col. 3 ll. 18–35. Thus, the 

Case: 15-2086 Document: 53-2 Page: 9 Filed: 05/27/2016
10 DAVID NETZER v. SHELL OIL COMPANY

patentee used “conventional fractionation” to refer to 

conventional distillation, i.e., a conventional method that 

separates compounds based on differences in their boiling 

points. 

Elsewhere, the specification repeatedly and consistently uses the term “fractionation,” whether modified by 

an adjective or not, in connection with temperature or 

boiling points. See, e.g., id. col. 2 ll. 58–59 (“naphtha 

resulting from crude oil fractionation has a boiling range 

of 100 to 350o F”); id. col. 2 ll. 62–63 (“naphtha undergoes 

further fractionation to separate a cut point of below 

200o F, light naphtha”); id. fig.1 & col. 5 ll. 9–14 (describing a “Fractionation & PSA Refrigeration” unit in Figure 

1, where ethylene, a more volatile compound, is recovered 

by “refrigerated fractionation,” and propylene and C4 mix, 

less volatile compounds, are each recovered by “warm 

fractionation”); id. col. 5 ll. 24–34 (stating that the hydrotreated pyrolysis gasoline undergoes “fractionation” for 

benzene recovery in two distillation columns). Although

the specification uses the word “distillation” only in some 

instances, id. col. 2 ll. 23, 60; id. col. 3, ll. 10–11; id. col. 8, 

ll. 12–13, the repeated and consistent references to “fractionation” in the context of boiling-point-based separation 

indicate that the patentee uses “fractionation” to refer to 

distillation specifically, not to generic “separation.”

Importantly, the patentee distinguished conventional 

extraction from fractionation in the specification, indicating that “fractionation” does not include conventional 

extraction. After identifying the azeotrope problem

encountered by “conventional fractionation,” id. col. 2 

ll. 17–20, the specification explains that “[t]he conventional method of benzene purification and separation from 

the above azeotropes is by aromatic extraction or extractive distillation processes, such as [the] Sulfolane [process],” id. col. 2 ll. 21–25 (emphases added), which 

produces >99.9% pure benzene, id. col. 2 l. 28. Thus, 

according to the patentee, conventional extraction and

Case: 15-2086 Document: 53-2 Page: 10 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 11

conventional fractionation are different methods. Unlike 

conventional fractionation, conventional extraction—

which includes the Sulfolane process—can successfully 

remove non-aromatic hydrocarbon azeotropes to produce 

highly pure benzene. The Sulfolane process is therefore

conventional extraction, not “conventional fractionation.” 

The Sulfolane process was developed by Shell in the 

1960s; it is a conventional method of separation. If one 

were to adopt Netzer’s proposed construction that “fractionation” means separation by any method, then “conventional fractionation” would mean separation by any

conventional method, which would encompass the Sulfolane process. That interpretation would be contrary to 

the specification.

Furthermore, as shown by the intrinsic record, the patentee clearly disclaimed conventional extraction, characterizing it as expensive and not required due to a shift in

market demand, and distinguishing it from the “present 

invention.” Id. col. 2 ll. 25–28, 33–37, 44–48, 51–55. The 

specification explains that there had been a strong market demand for “benzene of nitration grade, about 99.9 wt 

%,” id. col. 1 l. 54, but that such high purity benzene was 

no longer required in some circumstances; rather, benzene products from the “present invention” containing 

non-aromatic impurities can be used in its place. Id. col. 2 

ll. 46–48 (“the assumed non-aromatic impurities in the 

benzene, resulting from the application of the present 

invention” (emphasis added)); id. col. 2 ll. 54–55 (“This 

market shift is the major driving force behind the present 

invention.” (emphasis added)). Likewise, the patentee 

twice stated during prosecution that the claimed process 

is “particularly useful” “to produce a benzene product that 

need not have a purity over 99 wt%, much less over 99.9 

wt%, as previously required.” J.A. 261, 880 (emphases 

added).

Those clear statements indicate that the inventor contemplated the claimed invention to be different from 

Case: 15-2086 Document: 53-2 Page: 11 Filed: 05/27/2016
12 DAVID NETZER v. SHELL OIL COMPANY

conventional extraction, which produces highly pure, 

nitration-grade 99.9% benzene. If “fractionation” were to 

include conventional extraction, then the claimed process 

would yield 99.9% pure benzene and there would not be 

significant “non-aromatic impurities . . . resulting from 

the application of the present invention.” ’496 patent col. 

2 ll. 46–48; see also id. col. 3 l. 58, col. 4 ll. 26–30 (“In 

accordance with the inventive method,” “fractionation” 

produces “close to 98 wt % benzene.”).

To be clear, we only conclude that the patentee disclaimed conventional extraction, such as the Sulfolane 

process. We recognize that the claim language only sets a 

lower limit on the purity of the benzene product, and thus 

does not preclude other unconventional distillation methods that are capable of producing highly pure benzene. 

But in view of the disclaimer of conventional extraction in 

the publicly available intrinsic record, Netzer cannot now 

attempt to recapture the disclaimed subject matter.

Netzer also argues that construing “fractionating” as 

distillation would improperly exclude the preferred embodiment disclosed in Figure 1 of the ’496 patent. We 

disagree. In that disclosed embodiment, the pyrolysis 

gasoline is passed through a hydrotreater, and the resulting “hydrotreated pyrolysis gasoline” is then passed 

through two distillation columns to produce a benzene 

product with 98% to 99% purity. Id. fig.1 & col. 5 ll. 21–

26, 48–51. Contrary to Netzer’s argument, the hydrotreater embodiment does not compel a different meaning 

of “fractionating.” The disclosed embodiment merely adds

a hydrotreating step—a step that does not separate the 

individual components of the pyrolysis gasoline from each 

other, but rather hydrogenates the olefins in that mixture—before the fractionating step; it does not require the 

construction of “fractionating” to include hydrotreating, or 

any process other than distillation. Notably, dependent 

claim 19 is directed to a process “further comprising” a 

Case: 15-2086 Document: 53-2 Page: 12 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 13

hydrotreating step, id. col. 8 ll. 33–35, thus showing that 

hydrotreating is not part of the fractionating step.

Rather, the intrinsic record suggests that the patentee 

referred to the hydrotreated pyrolysis gasoline as a type 

of pyrolysis gasoline: the language of claim 1 defines 

“pyrolysis gasoline” as “comprising olefins, di-olefins and 

benzene,” id. col. 7 ll. 28–29, and the specification refers 

to the product from the hydrotreater as the “hydrotreated 

pyrolysis gasoline,” id. col. 5 l. 25, which is then distilled

twice to form benzene with 98% to 99% purity. Accordingly, under the proper construction of “fractionating,” the 

disclosed embodiment is within the scope of the claims. 

Netzer primarily relies on two pieces of intrinsic evidence, but neither supports its proposed construction. 

First, Netzer notes that dependent claim 11 recites “conventional fractionation in a distillation column.” Id. col. 8 

ll. 9–13. Netzer argues that if fractionation means distillation, then there would be no need to state “fractionation 

in a distillation column.” We find that argument unavailing. The quoted phrase merely requires that the fractionation, or distillation, occur in a distillation column as 

opposed to in another device. Such specific, clarifying 

language does not change the meaning of fractionation. 

Second, Netzer relies on a passage in the specification, which states that: “Fractionation and production of 

benzene with over 75 wt % purity from reformer reactor 

effluent by conventional distillation may become difficult 

. . . .” Id. col. 3 ll. 9–11. Netzer again argues that if 

fractionation means distillation, then it does not make 

sense to say “fractionation . . . by conventional distillation.” We disagree. Netzer has not quoted the full sentence. The omitted portion of the quoted sentence reads: 

“. . . because of the azeotrope forming characteristics of 

compounds such as dimethylpentanes, cyclohexane and 

methyl-cyclopentane.” Id. col. 3 ll. 11–13. Thus, that full 

sentence explains that the listed azeotropes make convenCase: 15-2086 Document: 53-2 Page: 13 Filed: 05/27/2016
14 DAVID NETZER v. SHELL OIL COMPANY

tional fractionation, i.e., conventional distillation, difficult. To avoid that problem, one may resort to unconventional fractionation techniques, such as the claimed 

process of cracking the C6–C7 azeotropes to convert them 

to shorter chain and more volatile hydrocarbons before 

fractionation. Thus, the quoted sentence is entirely 

consistent with, and indeed supports, our construction of 

“fractionating.”

Accordingly, the intrinsic evidence here points in only 

one direction, and requires that “fractionating” in this 

patent be construed as separating compounds based on 

differences in boiling points. The parties cite conflicting 

extrinsic evidence, which does not compel a different 

construction. As we have explained, extrinsic evidence 

may not be used to contradict claim meaning that is 

unambiguous in light of the intrinsic record. Summit 6, 

LLC v. Samsung Elecs. Co., 802 F.3d 1283, 1290 (Fed. Cir. 

2015).

We therefore conclude that “fractionating” in the present patent means separating compounds based on differences in boiling points, which excludes conventional 

extraction methods, such as the Sulfolane process.

B. Infringement

Netzer also argues that the district court erred in 

granting summary judgment of noninfringement. According to Netzer, under its proposed construction, Shell’s 

accused process satisfies the fractionating limitation

because Shell separates 99.9% pure benzene from pyrolysis gasoline. Even under Shell’s proposed construction, 

Netzer contends, Shell still literally infringes the ’496 

patent because it directs its pyrolysis gasoline through a 

series of process units, some of which are distillation 

columns, and forms 99.9% pure benzene in the end. It is 

irrelevant that the mixture also passes through an extractor as part of that process, according to Netzer, because

adding an extra step to an otherwise infringing process 

Case: 15-2086 Document: 53-2 Page: 14 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 15

does not defeat a finding of infringement. Netzer additionally argues that the district court erred in finding 

Netzer barred from relying on the doctrine of equivalents

to prove infringement, and that the accused process 

satisfies the function-way-result test as to the “fractionating” limitation. 

Shell responds that, under the proper construction of 

“fractionating,” i.e., distillation, or separating compounds 

based on differences in boiling points, Shell does not 

infringe the ’496 patent because it uses its own Sulfolane 

process, which uses extraction, not distillation, to form

>80% pure benzene. More specifically, Shell explains that 

its pyrolysis gasoline is refined in multiple steps to yield a 

mixture containing about 57% benzene, far below the 80% 

required by the claims; and Shell then uses the Sulfolane 

process to remove non-aromatic impurities in that mixture to produce 99.9% pure benzene. Shell also responds 

that Netzer is barred from asserting infringement under

the doctrine of equivalents because the patentee disclaimed the Sulfolane process. Even if Netzer is not 

barred, Shell argues, the Sulfolane process does not purify 

benzene in substantially the same way as “fractionating.” 

We agree with Shell that the district court did not err 

in granting summary judgment of noninfringement. 

Shell’s process does not literally meet the fractionating 

limitation. Shell relies on conventional extraction—more 

specifically, its own Sulfolane process—to refine a mixture 

containing about 57% benzene to a benzene product of 

greater than 80% purity. As we have explained, “fractionating” means distillation; it does not include conventional extraction. Moreover, the earlier steps of the Shell 

process only refine pyrolysis gasoline to produce a 57% 

pure benzene mixture, which does not satisfy the limitation “to form a purified benzene product comprising at 

least about 80 wt % benzene.”

Case: 15-2086 Document: 53-2 Page: 15 Filed: 05/27/2016
16 DAVID NETZER v. SHELL OIL COMPANY

It is true that a method claim with the word “comprising” appearing at the beginning generally allows for 

additional, unclaimed steps in the accused process, but 

each claimed step must nevertheless be performed as 

written. Dippin’ Dots, Inc. v. Mosey, 476 F.3d 1337, 1343

(Fed. Cir. 2007) (“[The] enumerated steps must . . . all be 

practiced as recited in the claim for a process to infringe. 

The presumption raised by the term ‘comprising’ does not 

reach into each of the six steps to render every word and 

phrase therein open-ended . . . .”). Netzer’s infringement 

theory requires rewriting the claimed step to read “fractionating the pyrolysis gasoline [and] form[ing] a purified 

benzene product” rather than “fractionating the pyrolysis 

gasoline to form a purified benzene product,” as the claim 

is written.

We are also unpersuaded by Netzer’s argument analogizing the accused process to the preferred embodiment 

of the ’496 patent, as both process the pyrolysis gasoline 

through multiple steps and generate >80% pure benzene 

in the end. As we have explained, hydrotreating is not 

part of the fractionating step. The hydrotreating step in 

the preferred embodiment merely produces a hydrotreated pyrolysis gasoline; it is not a step that separates the 

individual components of the pyrolysis gasoline. In the 

preferred embodiment, the hydrotreated pyrolysis gasoline is distilled twice to form >80% benzene. In contrast, 

nothing in the Shell process distills pyrolysis gasoline “to 

form” >80% benzene. 

Moreover, as indicated supra, the patentee disclaimed 

conventional extraction, including the Sulfolane process. 

Netzer cannot now assert that the claimed fractionating 

step is literally infringed by the Sulfolane process. Likewise, Netzer cannot show infringement under the doctrine 

of equivalents. The disclaimer of the Sulfolane process for 

literal infringement applies equally to infringement under 

the doctrine of equivalents. SciMed Life Sys., Inc. v. 

Case: 15-2086 Document: 53-2 Page: 16 Filed: 05/27/2016
DAVID NETZER v. SHELL OIL COMPANY 17

Advanced Cardiovascular Sys., Inc., 242 F.3d 1337, 1347 

(Fed. Cir. 2001). 

We agree with Shell, moreover, that no reasonable jury would find that the accused process performs substantially the same function in substantially the same way to 

obtain substantially the same result. Warner-Jenkinson 

Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 38–40 (1997). 

Shell’s Sulfolane process does not purify benzene to >80% 

purity in substantially the same way as the claimed 

process because almost all of the purification in the Sulfolane process is done through extraction, i.e., separating 

compounds based on solubility differences, which is 

substantially different from the claimed process of separating compounds based on differences in boiling points. 

Drawing all justifiable inferences in Netzer’s favor, we 

agree with Shell that Netzer cannot establish infringement under the doctrine of equivalents in light of the 

substantial difference between the claimed process and 

the accused process.

We therefore conclude that the district court did not 

err in granting summary judgment of noninfringement, 

either literally or under the doctrine of equivalents. 

CONCLUSION

We have considered the remaining arguments and

find them unpersuasive. For the foregoing reasons, we 

affirm the district court’s summary judgment of noninfringement.

AFFIRMED

Case: 15-2086 Document: 53-2 Page: 17 Filed: 05/27/2016