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 .
Claim Objections
Claim 2 is objected to because of the following informalities.
Claim 2 is drawn to providing a definition for the term “average ratio of active catalyst mass to effective cooling surface” recited in claim 1. The limitation of claim 2 may be redundant because the instant specification provides the same definition in paragraph [0030]. Applicant is suggested to incorporate claim 2 into claim 1, or cancel claim 2.
Appropriate correction is required.
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.
Claims 1-9 and 11-20 are 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 1 recites “A method for producing ethylene by oxidative dehydrogenation of ethane” and also recites “using a shell-and-tube reactor...” (emphasis added). Claim 1 is considered indefinite because the claim body does not include any process step drawn to “producing ethylene by oxidative dehydrogenation of ethane” and merely recites a use of a shell-and-tube reactor without any active, positive steps delimiting how this use is actually practiced. Claim 1 is interpreted to include a step of feeding a feed comprising ethane and oxygen to the shell-and-tube reactor operating under oxidative dehydrogenation conditions.
Claims 2-9 and 11-20 are also rejected under 35 U.S.C. 112(b) by virtue of their dependency upon claim 1.
Claim 3 recites “a weight hourly space velocity of greater than 3 or 5 kg and less than 20 kg feed per hour per kg of catalyst.” A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In claim 3, the narrow limitation “greater than … 5 kg” falls within the broad limitation “greater than 3.” The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Claim 4 recites “The method according to claim 1, wherein the shell-and-tube reactor is operated at a linear velocity greater than 300, 400, or 500 cm/s.” The narrow limitation “greater than …400, or 500 cm/s” falls within the broad limitation “greater than 300 … cm/s.” The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Claims 5 and 11 each recite “a maximum temperature in the plurality of catalyst beds is less than 500 or 450 °C.” The narrow limitation “less than …450 °C” falls within the broad limitation “less than 500 …°C.” The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Examiner’s Comment
The following are suggestions provided by the examiner to address the indefiniteness issues and objections discussed above and also to improve clarity and form of the pending claims.
Claim 1
A method for producing ethylene by oxidative dehydrogenation of ethane, comprising:
providing a shell-and-tube reactor having reaction tubes extending between a first end and second end, wherein a plurality of catalyst beds are disposed in each of said reaction tubes, and in each of said reaction tubes, a ratio of a total length of the plurality of catalyst beds between said first end and said second end to a diameter of each of said reaction tubes has a value between 150 and 400, and
feeding a feed comprising ethane and oxygen to the shell-and-tube reactor operating under oxidative dehydrogenation conditions;
wherein:
the shell-and-tube reactor is operated at a linear velocity of 250 to 800 cm/s; and
the plurality of catalyst beds are configured such that the plurality of catalyst beds in each of the reaction tubes have a different catalyst activity; [[and]]
an average ratio of active catalyst mass to effective cooling surface for the plurality of catalyst beds in each of the reaction tubes is in a range between 1.5 and 5 kg/m2, wherein in at least one of the catalyst beds in each of the reaction tubes considered individually, a ratio of active catalyst mass to effective cooling surface is in the range between 1.5 and 5 kg/m2; and
the average ratio of the active catalyst mass to the effective cooling surface for the plurality of catalyst beds in each of the reaction tubes a quotient between a sum of the active catalyst masses in all of the respective catalyst beds and the sum of all inner surfaces of the reaction tube surrounding these catalyst beds, respectively.
Claim 2: Canceled.
Claim 3
The method according to claim 1, wherein the shell-and-tube reactor is operated at a weight hourly space velocity of greater than 3
Claim 4
The method according to claim 1, wherein the shell-and-tube reactor is operated at a linear velocity greater than 300
Claim 5
The method according to claim 4, wherein the shell-and-tube reactor is operated such that a maximum temperature in the plurality of catalyst beds is less than 500
Claim 6
The method according to any one of the preceding claims claim 5, wherein a packing selected from rings, pellets, [[and]] extrudates, or combinations thereof is used in the plurality of catalyst beds.
Claim 10
A plant for producing ethylene by oxidative dehydrogenation of ethane, comprising:
a shell-and-tube reactor having reaction tubes extending between a first end and second end, wherein:
a plurality of catalyst beds are disposed in each of said reaction tubes, and
in each of said reaction tubes, a ratio of a total length of the plurality of catalyst beds between said first end and said second end to a diameter of each of said reaction tubes has a value between 150 and 400, and
a feed source configured to a provide a feed comprising ethane and oxygen to the shell-and-tube reactor;
wherein:
the shell-and-tube reactor is configured to operate at a linear velocity of 250 to 800 cm/s;
[[a]] the plurality of catalyst beds are configured such that the plurality of catalyst beds in each of the reaction tubes have a different catalyst activity; and
an average ratio of active catalyst mass to effective cooling surface for the plurality of catalyst beds in each of the reaction tubes is in a range between 1.5 and 5 kg/m2, wherein in at least one of the catalyst beds in each of the reaction tubes considered individually, a ratio of active catalyst mass to effective cooling surface is in the range between 1.5 and 5 kg/m2; and
the average ratio of the active catalyst mass to the effective cooling surface for the plurality of catalyst beds in each of the reaction tubes a quotient between a sum of the active catalyst masses in all of the respective catalyst beds and the sum of all inner surfaces of the reaction tube surrounding these catalyst beds, respectively.
Claim 11
The method according to claim 1, wherein the shell-and-tube reactor is operated such that a maximum temperature in the plurality of catalyst beds is less than 500
Claim 12
The method according claim 4, wherein a packing selected from rings, pellets, [[and]] extrudates, or combinations thereof is used in the plurality of catalyst beds.
Claim 13
The method according claim 1, wherein a packing selected from rings, pellets, [[and]] extrudates, or combinations thereof is used in the plurality of catalyst beds.
Allowable Subject Matter
Claim 10 is allowable over the prior art.
Claims 1-9 and 11-20 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
The following is a statement of reasons for the indication of allowable subject matter. Bos et al. (WO 2017/144584 cited in IDS dated 09/01/2023) disclose a process for producing ethylene by oxidative dehydrogenation of ethane, the process comprising: supplying a feed gas comprising ethane and oxygen to an inlet of a reactor vessel, the reactor vessel comprising a reactor shell, a plurality of reactor tubes disposed within an interior of the reactor shell, and a perforated partition that divides the interior of the reactor vessel into an upstream region and a downstream region, wherein the plurality of reactor tubes comprise: (i) an upstream catalyst bed positioned within the upstream region that comprises an oxidative dehydrogenation catalyst comprising tellurium, and (ii) a downstream catalyst bed positioned with the downstream region that comprises an oxidative dehydrogenation/oxygen removal catalyst; and contacting the feed gas with the oxidative dehydrogenation catalyst in the upstream catalyst bed, followed by contact with the oxidative dehydrogenation/oxygen removal catalyst in the downstream catalyst bed, to yield a reactor effluent comprising the ethylene. The reference, however, fails to teach that the reactor is operated at a linear velocity of 250 to 800 cm/s and the average ratio of catalyst mass to effective cooling surface for the catalyst beds in the reaction tubes is in a range between 1.5 and 5 kg/m2 (pg. 3, line 26 – pg. 4, line 16).
Bos et al. (US 9,963,412 B2, hereinafter “Bos ‘412”) disclose a process of the oxidative dehydrogenation of an alkane containing 2-6 carbon atoms, wherein a gas stream comprising oxygen and the alkane is contacted with a mixed metal oxide catalyst at a linear velocity of said gas of at least 10 cm/s (col. 1, lines 53-60). Bos ‘412 teaches that the linear velocity may be in the range of from 10 to 500 cm/s (col 4, lines 4-9). However, the instant specification demonstrates that a relatively low linear velocity, such as lower than 250 cm/s, may lead to reduced relative molar ethylene yield based on ethane feed at reactor inlet and load with insert per cooling surface (Spec., [0098]-[0101]). Therefore, the instant disclosure is considered to have shown criticality of the lower limit of the claimed linear velocity range. There is no sufficient guidance in the prior art which would have reasonably motivated one of ordinary skill in the art to operate the oxidative dehydrogenation of ethane at the claimed linear velocity range in conjunction with the claimed average ratio of active catalyst mass to effective cooling surface in a shell-and-tube reactor.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JASON Y CHONG whose telephone number is (571)431-0694. The examiner can normally be reached Monday-Friday 9:00am-5:30pm.
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/JASON Y CHONG/Examiner, Art Unit 1772
/IN SUK C BULLOCK/Supervisory Patent Examiner, Art Unit 1772