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 1 is objected to because of the following informalities: the preamble states “a method of refining…from a manufacturing process comprising:”. The wording seems to imply that the claimed steps are directed to the manufacturing process. However, the office understands that is not what is intended, but rather the refining method. The office recommends amending to recite “a method of refining…from a manufacturing process, wherein the method of refining comprises:”.
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 2, 3, 6 and 8 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.
Regarding claim 2, it is unclear what the relationship is between “a dividing wall column” (two recitations) and the dividing wall column introduced in claim 1 and how many dividing wall columns are intended. Based on a review of the specification, the office believes the references in claim 2 are intended to limit the dividing wall column introduced in claim 1, and not to introduce distinct columns. The office recommends amending claim 2 to recite:
“The method as claimed in claim 1, wherein the dividing wall column has from 40 to 80 stages and wherein the drawing comprises:
drawing the AC stream from the product side of the dividing wall at a point 1 to 5 stages above the bottom of the dividing wall; and
drawing the purified EO stream from the product side of the dividing wall at the 2nd to 8th stage from the top of the dividing wall column.”
Claim 3 recites the limitation "the point at which the feeding of the water takes place" in lines 3-4. There is insufficient antecedent basis for this limitation in the claim.
Regarding claim 6, in the first step therein, it is unclear what the relationship is between the recited component and streams and those introduced in claim 5, from which claim 6 depends. In particular:
What is the relationship between “a partial condenser” in claim 6 and recitation of the same in claim 5? The office understands them to be the same and recommends amending to recite “the (or said) partial condenser” to make clear Applicant is referring back to the partial condenser already introduced.
What is the relationship between “a vent gas stream” in claim 6 and “a gas phase” in claim 5? Are these distinct streams and, if so, does that mean the partial condenser outputs two gas streams: a gas phase and a vent gas stream?
What is the relationship between “a reflux liquid stream” in claim 6 and “a reflux liquid” in claim 5? The office understands them to be the same and recommends amending to recite “the (or said) reflux liquid”.
Further regarding claim 6, there are two recitations of “a jet compressor” to refer to two distinct jet compressors. The office recommends amending to recite “a first jet compressor” and “a second jet compressor” to clarify the distinct components of the two-stage jet compressor.
Claim 8 recites the limitation "the point where the crude EO feed stream enters" in line 3. 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.
Claims 1-5 and 7-10 are rejected under 35 U.S.C. 103 as being unpatentable over Coffey (US 5,529,667) in view of Bassler et al (US 2005/0211541).
Regarding claim 1, Coffey is directed to a process for recovering ethylene oxide (EO) from an aqueous ethylene oxide solution (crude EO) produced in a manufacturing process (see Abstract). The recovering process comprises distilling the crude EO feed stream in a series of two distillation columns (stripping column 50 and aldehyde remove column 51). From the second column in the series, two side draws are obtained: a purified EO stream and an acetaldehyde (AC) stream, where the EO is drawn at a point above the AC stream (see Figs. 1-3; col. 3, line 57 – col. 4, line 12; col. 4, line 58 – col. 5, line 9; col. 8, lines 15-17 and 45-46). The purified EO stream comprises at least 99.5 wt.% of EO (see col. 8, lines 45-52, the stream contains 10 ppm or less of formaldehyde, 58 ppm or less of acetaldehyde, and less than 300 ppm water).
Coffey differs from the claimed invention in that the distillation is carried out in two serially connected distillation columns compared to a dividing wall column (DWC) as claimed.
Bassler is directed to a process for purification of an oxirane by distillation. In particular, Bassler discloses separation in a DWC to separate a crude oxirane feed into an overhead stream, two middle streams, and a bottoms stream (see Fig. 4; [0086]). The DWC contains within it a dividing wall having a top and a bottom and having a receiving side and a product side, and a bottom portion located below the dividing wall. The two middle streams are withdrawn from the product side (see Fig. 4). Bassler discloses that the DWC configuration is advantageous over serially connected columns because it has a smaller outlay and lower energy consumption (see [0014]-[0015]).
It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to modify the method of Coffey by carrying out the serial stages of distillation in a single DWC instead, as suggested by Bassler, in order to provide a more energy efficient process which takes up less space. The office notes that such modification would entail withdrawing the EO stream from the dividing wall column on the product side at a point above the AC stream, given that the EO stream is withdrawn at a point higher than the AC stream in the two-stage configuration of Coffey.
Regarding claim 2, Coffey discloses wherein the distillation column comprising between 37 to 64 stages (see col. 6, lines 16-23, total of the five regions). The EO stream is drawn from the 8th stage from the top of the column (see Fig. 3). Based on the combination of references, as outlined above, wherein the process is carried out in a DWC, a person of ordinary skill in the art would readily determine, by routine experimentation, the number of stages needed in the column overall, as well as the respective stage at which to draw the EO and AC streams from the product side of the dividing wall, which provides sufficient separation of the components of the mixture as well as results in the desired purity of the EO product stream. Absent a showing of criticality or unexpected results, the claimed stages within the column and product withdrawal points are not considered to patentably distinguish the instant claims over the cited prior art.
Regarding claim 3, in Coffey, the first column is a stripping column, which would be equivalent to the receiving side in the combination of references. Steam is fed to the column as a stripping medium (see col. 4, lines 58-61). Therefore, in the modified Coffey process, it would have been obvious to a person of ordinary skill in the art to feed a water (or steam) stream into the receiving side of the DWC. Determining the point at which the streams are introduced and the temperature thereof amounts to nothing more than routine experimentation in order to ensure adequate separation of gaseous components from the crude EO stream (see also Coffey: col. 5, lines 19-20, which discloses a temperature in the stripping column of 20 to 100°C, providing evidence that feeding the stripping medium at a temperature as claimed would have been obvious to a person of ordinary skill in the art).
Regrading claim 4, Coffey discloses drawing from the column a bottoms stream 56 comprising water and ethylene glycol from the bottom and an overhead stream 54 comprising ethylene oxide, gases, and condensable vapors from the top (see Figs. 2 & 3; col. 6, lines 44-61; col. 8, line 53 – col. 9, line 10). The column is indirectly heated by heating at least a portion of the bottoms stream in a reboiler 59 which is heated by steam (see col. 7, lines 49-54). While Coffey does not explicitly disclose a second reboiler, duplication of parts is prima facie obvious absent new or unexpected results. MPEP 2144.04 VI B.
Regarding claim 5, Coffey discloses recycling the overhead stream through a partial condenser 89 to form a reflux liquid 81 and a gas phase 90 and feeding back to the column the reflux liquid (see Figs. 2 & 3; col. 8, lines 53-61; col. 9, lines 63-67).
Regarding claim 7, Coffey discloses preheating the crude EO stream using water from a recycled bottoms stream (see col. 7, lines 38-39 and 62-64). The crude EO stream is heated to a temperature between about 35 to 120°C (see col. 23-27), overlapping the claimed range.
Regarding claim 8, Coffey in view of Bassler discloses wherein the preheating of the crude EO feed stream takes place in a heat exchanger that is directly connected to the receiving side of the DWC at a point where the crude EO feed stream enters the DWC (see Coffey: Fig. 2, HEX 64 and entry line 32).
Regarding claim 9, Coffey in view of Bassler does not explicitly disclose the residence time at which a mixture containing more than 1 wt.% of each of EO and water is present at a temperature above 80°C. Nevertheless, it is considered that a person of ordinary skill in the art would optimize, by routine experimentation, the temperature conditions within the DWC in the process of Coffey in view of Bassler which achieves maximum separation of EO from the mixture at the desired purity. Absent a showing of criticality or unexpected results, the claimed residence time at the specified temperature is not considered to patentably distinguish over the cited prior art (see Coffey: col. 8, lines 40-52).
Regarding claim 10, Coffey discloses pressures in the column are generally from about 25 to 100 psig (about 2.7 to 7.8 atm absolute) (see col. 10, lines 20-28), overlapping the claimed range.
Allowable Subject Matter
Claim 6 would be allowable if rewritten 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 and to include all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: Coffey, considered with Bassler, cited above, are considered to be the closest prior references. The cited references do not appear to disclose the additional features encompassed by claim 6, as they are presently understood by the office in light of the 112(b) rejections. In particular, neither Coffey nor Bassler discloses compressing scrubbed vent gas by either mechanical compression or by passing through a two-stage jet compressor to from a recycled vent gas stream that is used as the heating medium in the second reboiler.
As noted in the rejection above, while Coffey does not explicitly disclose two reboilers, the office has taken the position that duplication of parts is prima facie obvious. However, the cited references do not adequately disclose or suggest the specific arrangement encompassed by claim 6, where one reboiler is heated by steam and the other is heated by compressed vent gas separated from the overhead stream of the column. While compression of gases to provide heat for heat exchange is generally known, there lacks sufficient suggestion to provide motivation for a person of ordinary skill in the art to modify Coffey and Bassler in such a way as to arrive at the specifically claimed embodiment represented in claim 6.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RENEE ROBINSON whose telephone number is (571)270-7371. The examiner can normally be reached Monday - Thursday 8:00a-5:00p and Friday 8:00a-2:00p.
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/Renee Robinson/Primary Examiner, Art Unit 1772