T 316/10 – Simply Suppressing

Both parties appealed against the decision of the Opposition Division to maintain the patent in amended form.

Claim 1 of the patent as granted read:

1. A process for the production of olefins comprising passing a synthetic naphtha to a steam cracker wherein at least a portion of the synthetic naphtha is converted to olefins characterised in that the synthetic naphtha is a combined synthetic naphtha produced from a process comprising

a) contacting a synthesis gas stream at an elevated temperature and pressure with a Fischer-Tropsch catalyst in a Fischer-Tropsch reactor to generate a hydrocarbon product stream

b) separating the hydrocarbon product stream to provide at least one lighter fraction and at least one heavier fraction

c) subjecting at least a portion of the heavier fraction to hydrocracking and/or hydroisomerisation in a hydroprocessing reactor to produce an upgraded hydrocarbon product stream

d) combining the lighter fraction with the upgraded hydrocarbon product stream to produce a combined hydrocarbon stream and

e) fractionating at least a portion of the combined hydrocarbon stream to produce the combined synthetic naphtha stream.

The Board found this claim to lack inventive step:

[2.1] The Board concurs with the finding of the OD, undisputed by the proprietor, that the assessment of inventive step may reasonably be made starting from the prior art disclosed in document D1 which mentions, inter alia, that the naphtha obtained from the Sasol process illustrated in Figure 4 of this citation is an excellent feed for the production of olefins via steam cracking (see document D1, page 6, point 3, the passage reading “In addition, the process also delivers a significant fraction of naphtha, an excellent feed for the production of olefins via steam cracking”; and at page 11, last paragraph, the passage reading: “The Sasol SPD naphtha is an excellent feed for the production of lower olefins, in particular ethylene, by steam cracking”).

[2.2] The Board notes that the processes of Figure 5 only differ from the prior art of departure in that the L-fraction is not hydrocracked, but combined as such with the UHP-stream (i.e. with the hydrocracked H-fraction).

[2.3] The opponent has argued that according to undisputedly previously existing common general knowledge (that a high content of olefins in the naphtha stream undergoing steam cracking resulted in large amounts of coking and, thus, was detrimental to the yield in olefins) even the most preferred processes of Figure 5 could produce substantially worse yields in olefins in comparison to the prior art, when the L-fractions generated in these processes have high olefin contents. Hence, the only problem credibly solved over the whole ambit of granted claim 1 would be that of providing in general further olefins production processes possibly simpler than the prior art, regardless as to whether these further processes achieve or not the excellent yields of the Sasol process.

The proprietor has rejected such argument by stating that the experimental data reported in the examples of patent-in-suit would instead prove false this common general knowledge, demonstrating that good yields in ethylene could even be obtained by steam cracking L-fractions as such (i.e. L-fractions rich in olefins). Hence, according to the proprietor’s line of argument, the technical problem solved over the whole ambit of the granted claim was rather that - also acknowledged by the OD (for the then pending Auxiliary Request 5) - of providing a simpler olefins production process whose yields in olefins were excellent, i.e. comparable to those of the process of document D1.

[2.4] The Board finds unconvincing the reasoning of the proprietor because the examples in the patent provide experimental data that (beside not being in accordance with granted claim 1) are based on a single L-fraction only containing about 10% by weight of olefins (see in the patent-in-suit the Table at page 6 entitled “Straight Synthetic Naphtha”).

Instead, as noted by the opponent […] and undisputed by the proprietor, granted claim 1 does not limit in any way the amount of olefins possibly present in the L-fraction. In particular, the granted claim sets no limitation for the kind of FT-process taking place in step “(a)” and, thus, embraces the possibility of using, for instance, the same FT-process used in document D1, that results in L-fractions possibly containing up to 35% by weight olefins.

Thus, the experimental data provided with the examples in the patent-in-suit are insufficient at rendering credible that e.g. also the claimed processes in which the L-fractions contain much more than 10% by weight of olefins are nevertheless steam cracked to olefins without substantial coking and, thus, with excellent yields.

Hence, the Board concludes that the technical problem credibly solved over the whole range of granted claim 1 (and thus also by the processes of Figure 5 in which the generated L-fractions substantially more than 10% by weight olefins) can only be that identified by the opponent, i.e. that of providing in general further olefins production processes simpler than the prior art, regardless as to whether these further processes produce yields in olefins comparable or worse than those produced in the prior art of departure.

[2.5] In the opinion of the Board, a person skilled in the art who is aiming at further olefins production processes that are simpler than that of document D1 but who does not attribute any particular relevance to the (normally implicit) aim of also retaining the convenience of the prior art of departure in terms of yields in the final product, would consider obvious to solve the posed problem by suppressing any of the steps of the prior art of departure that are not absolutely essential in order to obtain some olefins in the final product.

Such person would thus attempt to identify any such suppressible steps among all the process steps used in document D1 that are not essential for the production of olefins, including those that are explicitly or implicitly identified in this citation as essential for the achievement of low coking and high yields or of other advantages.

The Board notes that document D1 not only undisputedly teaches to such skilled person that the intermediate separate hydrocracking steps of both fractions are only needed for upgrading the naphtha - i.e. that the hydrocracking steps are only mandatory if one aims at the formation of an “essentially paraffinic” naphtha […] that allows to minimize the coking during steam cracking and, thus, to maximizing the yields in olefins – but even implicitly disclose at least the possibility to by-pass the intermediate hydrocracking of the L-fraction, as apparent from the dotted lines in Figure 4.

The Board concludes that no inventive ingenuity is required to the skilled person for arbitrarily selecting the solution to the posed technical problem consisting in suppressing the intermediate hydrocracking of the L-fraction, i.e. a simplification of the prior art of departure that is not only obvious per se but even suggested by the dotted lines in Figure 4.

In solving the posed technical problem in such an obvious manner the skilled person arrives at variants of the processes of Figure 5 that are also manifestly encompassed by granted claim 1.

The Board concludes, therefore, that this claim embraces processes for the production of olefins that are obvious in view of document D1. Accordingly, the Main Request is found to violate A 56 EPC (1973) and is refused.

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