COMMISSIONER'S DECISION
Obviousness. claim 1 was considered obvious in view of the cited art, the
others acceptable in view of that art. Rejection modified.
This decision deals with Applicant's request for review by the
Commissioner of Patents of the Final Action of application
410,060 (Class 23-348) filed August 25, 1982. Assigned to Foster
Wheeler Energy Corporation, it is entitled USE OF WASTE SOLIDS
FROM FLUIDIZED BED COMBUSTION PROCESSES FOR ADDITIONAL FLUE GAS
DESULFURIZATION. The inventors are Robert D. Stewart and Robert
L. Gamble. The Examiner in charge issued a Final Action on
August 1, 1985, refusing to allow the application. By letter
dated October 27, 1988, the Applicant withdrew the request for a
Hearing.
The invention relates to a flue gas desulfurization process using
the fine and coarse wastes from a fluidized bed combustion
system, as shown in figure 1 reproduced below:
(see formula I)
In the Applicant's system sulfurous coal burns in air in the
presence of limestone particles in a fluidized bed 10 and wastes
emerge as exhaust gas 11, fine dusts 18, and coarse particles 20.
To reduce the SO2 and SO3 content in the exhaust gas, the coarse
waste is ground at 30 to fine particles 33 to expose additional
active surface area and so obtain an increased alkaline value,
and the fine particles are fed into the fluidized bed to act on
the exhaust gas. The fine particles may be mixed with the fine
dusts and either fed to the fluidized bed or, to slaker/hydrator
34 to produce a calcium hydroxide slurry 38 to be injected into
dry scrubber 43, or, slurry 38 may be thinned with water and fed
to wet scrubber 46. The scrubbers clean the exhaust gas 11.
Additionally, ash particles 28 from an adjacent combustion system
22 may undergo a water/steam treatment 32 before entering
grinding means 30 to mix with particles 20 to produce the fine
particles 33. The exhaust gas from system 22 may also be treated
by the scrubbers.
The examiner refused all the claims in view of the following
patents:
British Patent
824,883 Dec. 9, 1959
United States Patents
3,708,266 Jan. 2, 1973 Gustavsson
3,751,227 Aug. 7, 1973 Robinson
4,081,513 Mar. 28, 1978 Moss
The British Patent to Atomenergi describes a method of burning
the combustible constituents of a sulfur-containing shale or fuel
in a fluidized bed with limestone to bind a great part of the
emitted sulfur in the solid combustion residue. In the
Atomenergie process, the grains of solid fuel are said to be
below 6 mm., and the combustion temperature below the temperature
of rapid dissociation of the carbonate.
The Gustavsson Patent sets forth apparatus to wash sulfur dioxide
from flue gases originating from coal fired systems, as shown in
figures 1 and 2 reproduced below:
(see formula I, II)
The SO2 gas enters absorption column 1 at 2, entrains calcium
carbonate particles from a slurry 6 fed to the bottom of the
column, and reacts with them in rising to form an inactivated
sulphite/sulphate coating thereon. The cleaned gas emerges at 3
and the coated particles are led from the top 4 to a mill 7.
Entering tangentially at 4a, the coated particles are crushed by
grinding bodies 9 to expose active areas in being reduced in
size. Part of the flow leaving mill 7 is passed through 4c by a
pump P to enter tangentially in the mill, level with 4a to assist
in grinding. Consumed absorbent is discharged at 8.
The Robinson patent pertains to apparatus to pass a waste gas
through a moving mass of limestone particles, as shown in figure
1 reproduced below:
(see formula I)
The SO2 containing gas enters from the bottom 3 to column 10 and
reacts with limestone particles B to form a coating on their
exterior. The treated air exits at 6. Column 10 and tray 9
rotate at different speeds and subject the coated particles to
abrasive action which exposes fresh active surfaces as they move
from the column to the tray and are forced by plow 18 to drop
into the downwardly inclined rotary conveyor 20 to elevator 21.
The elevator feeds the recycled particles back to the column.
Spent substance is removed at 7.
In the Moss system, shown by figure 1 below,
(see formula II)
gas 10 bearing SO2 is introduced at the bottom of a bed of
particles 12 containing calcium oxide. The heat from the gas
fluidizes the lower part of the bed which acts with the slurry
from line 14 so that the water evaporates and the sulphites are
converted to agglomerates of sulphate solids/solutes. The
agglomerates are removed at 17 and are ground to a smaller size,
and returned via line 18 to the top particles 12 to act on the
upwardly flowing vapors to fix SO2. Additional particles may be
added via line 18. The resulting vapor/fines mixture is scrubbed
20 by a lime slurry 21 to remove SO2 and the fines, which are
then separated in vessel 23. The resulting gas leaves at 24 and
the water/solids mix passes from the bottom 25 to settling tank
27 for mixing with a lime/water slurry from tank 28. Pump 15
moves the coarse particles from the base of tank 27 to the base
of particle bed 12 for the fluidizing action.
In rejecting all the claims in view of the cited patents, the
Examiner said in part, as follows:
...
It is common general knowledge that if the surface of a
sorbent becomes fouled its ability to function as a
sorbent is impaired; see Robinson and Gustavsson, for
example. It is also well known to grind a spent sulfur
oxide sorbent such as limestone to remove surface
fouling and to reduce the particle size of the
initially supplied coarse limestone (see Gustavsson).
Given the foregoing it is expected skill to modify the
fluidized bed combustion process of British patent
824,883 in the manner proposed by the applicant.
Accordingly claims 1-7 are rejected.
Claims 8-18 are rejected in view of the above discussed
patents in combination with Moss which teaches the
injection of aqueous alkaline material into a fluidized
bed process for the purpose of controlling sulfur
emissions.
Applicant is respectfully requested to note that the
claims are being rejected because they are considered
to be obvious in view of the references, not because
the references may be mosaiced to establish
anticipation. The latter practice is an American one
that does not prevail in Canada.
Robinson was cited for the purpose of establishing that
it is known that if the surface of a sorbent becomes
fouled, its ability to function as a sorbent is
impaired. Thus it is immaterial that Robinson does not
comminute, remove or circulate. What is germane is the
fact that fresh surfaces are provided, thereby renewing
the sorbent.
Similarly, Gustavsson was cited to show that a spent
sulfur oxide sorbent such as limestone can be ground to
remove surface fouling (and to reduce the particle size
of the initially supplied coarse limestone) and then
returned to the gas purification process from which it
originated. Therefore, it is immaterial that
Gustavsson does not relate to a fluidized bed process.
Given the foregoing it is expected skill to modify the
fluidized combustion process of British patent 824,883
in the manner proposed by the applicant. Claims 1-7
are obvious in view of British patent 824,883 when
considered in conjunction with the common general
knowledge that is exemplified by Robinson and
Gustavsson. These claims are rejected for this reason.
Moss was cited for the purpose of establishing that
injection of aqueous alkaline material into a fluidized
bed process, for the purpose of controlling sulfur
emissions (a feature in instant claims 8-18), is known.
It is not material that Moss does not grind or
comminute. All that Moss must teach in order to
sustain the examiner's position is the injection (in
the locale and for the purpose noted above) of aqueous
alkaline material, and this it does. Moss thus
augments the teachings of British patent 824,883, with
which it is obvious to combine as both relate to the
combustion of fuel in a fluidized bed.
Claims 8-18 are, given the common general knowledge
that is exemplified by Robinson and Gustavsson, obvious
in view of the combination consisting of British patent
824,883 and United States patent 4,081,513. Claims 8-
18 are rejected for this reason.
...
The Applicant argues that the claims are acceptable in the
following terms, in part:
(The Examiner) postulates that a sorbent's ability to
function as a sorbent is impaired when its surface
becomes fouled and that the prior art references of
Robinson and Gustavsson set out methods and apparatus
for presenting fresh surfaces of limestone to further
act as a sorbent of sulfur oxide. Having said that,
Examiner Kirk then jumps to the British patent of
fifteen years earlier wherein carbon-containing shale
is "burned" with limestone -- and also with some
chlorides to reduce the sulfur oxide content of the gas
emitted from the burning.
... To project the attrition of the limestone particles
of Gustavsson into the desulfurization of the shales of
the British patent is not an obvious step even in the
eyes of the knowledgeable and fully informed skilled
artisan. The Applicant has taken the subject matter of
Robinson and Gustavsson -- and particularly of
Gustavsson -- and has by experiment and trial and
testing managed to recycle and recrush the coarse
limestone sorbent particles and reinjected them into
the fluid bed of sulfurous fuel particles for further
desulfurizing effect. The lack of obviousness in
applying the attrition of limestone particles in a
fluidized bed of fuel particles is enhanced by the fact
that since Gustavsson and Robinson (and Moss), there
have been no other prior art disclosures available to
show the application of the 1973 subject matters to
fluidized beds of solid particles in the past twelve
years. In order to reject claims on the basis of
obviousness the subject matters of one published
reference must be directly applicable to the subject
matter of the earlier publication and there is nothing
to show that the coated limestone sorbent particles of
Gustavsson could be mixed with the carbon shales of
Atomenergi's method and then withdrawn for attrition
and recycling. Such attrition would have to take place
with the slag shale particles as well as the sorbent
particles and such recycling and crushing is obviously
not feasible.
Five years after Robinson and Gustavsson, Moss shows
that sulfur from the coal is fixed in the limestone as
sulphides and transferred downstream to a regenerator
with oxygen to convert the sulphides to the oxides,
after which the oxide containing regenerated limestone
particles are returned to the bed of fluidized coal
particles. Even with the knowledge of Robinson and
Gustavsson, Moss twenty years after the Atomenergi
patent for removing sulfur from shale did not show any
knowledge or suggestion or possibility of creating
fresh surfaces in the regenerated limestone particles
by crushing or attriting. It is the Applicant's
position that to now academically hold that it is now
obvious to so attrite the. limestone sorbent particles
in the desulfurization of a fluid bed of pulverized
sulfurous fuels is stretching the concept of
accumulation of previous publications to establish such
obviousness.
In contrast to such holdings of obviousness it is the
Applicant's restated position that Examiner Kirk is
assembling the subject matters of the published
references in a mosaic to anticipate the definition of
this invention in the claims. Examiner Kirk has
rejected the Applicant's position on mosaicing on the
basis that the practice is an American one and does not
prevail in Canada. The Applicant draws the Board's
attention to Mico Products Ltd. v. Acetol Products
Inc., (1930) Ex. C.R. 64 at 72. The accepted and
acknowledged author on Canadian Patent law, Dr. Fox, in
his Fourth Edition of his textbook on Canadian Law and
Practice Relating to Letters Patent for Inventions
recites at Page 138 with approval James L.J. in Von
Heyden v. Neustadt:
"What we have got in this case is not one
clear statement by one writer, but a mass of
paragraphs exhumed by the industry of the
defendant's advisers from a number of
publications...We are of opinion that if it
requires this mosaic of extracts from annals
and treatises spread over a series of years,
to prove the defendant's contention, that
contention stands thereby self-condemned.
...And even if it could be shown that a
patentee had made his discovery of a
consecutive process by studying, collating
and applying a number of facts discriminated
in the pages of such works, his diligent
study of such works would as much entitle him
to the character of an inventor as the
diligent study of the works of nature would
do."
At Page 139 Dr. Fox states
"The rule against making a mosaic of
documents does not apply when the documents
are connected together and form a consistent
whole ......where anybody reading one is
referred by cross-reference to the others."
Examiner Kirk has applied the Moss patent specifically
to establish the prior occurrence of an injection of
alkaline material into the fluid bed process and the
Applicant does not deny or contradict that prior
subject matter. Nevertheless, the alkaline slurry is
only an additional step in Claims 8 et seq and it does
not form any part of broad Claim 1. In this manner,
the Applicant believes that it is clear that Moss has
been mosaiced with Gustavsson and/or Robinson to reject
Claim 8 and then only with the combination of all two
(or three) prior publications can be taken back fifteen
years in time to employ them with the Atomenergi method
for extracting burnable gases from oil shales with
reduced sulfur content.
In summary, the Applicant's position is that the
desulfurizing treatment of gases with comminution of
the sorbent particles can not be combined with the oil
shale treatment of the Atomenergi patent because the
comminution of Gustavsson could not be applied to the
Atomenergi shale particles.
The Issue before the Board is whether the subject matter of
claims 1 to 18 is obvious in view of the cited patents. Claim 1
reads:
A process for obtaining additional flue gas
desulfurization using waste solids from a fluidized bed
combustion system in which sulfurous fuels are burned
in a bed of acceptor particles, comprising the steps
of:
(1) withdrawing coarse waste particles from said
fluidized bed combustion system;
(2) subjecting said coarse waste particles to
means for attriting and disintegrating whereby said
coarse waste particles are reduced to finely divided
particles having increased available alkaline chemical
value; and,
(3) injecting said finely divided waste particles
into said fluidized bed combustion system whereby
additional flue gas desulfurization is achieved.
We observe the Atomenergie patent discloses a one stage removal
of sulfur from waste gas by using a certain size of particles and
a combustion temperature below the dissociation temperature of
carbonates in a fluidized bed to bind sulfur that would otherwise
exit in the waste gas. We learn that the Moss patent provides a
two stage removal of sulfur from a waste gas. The first stage,
similar to Atomenergie, reacts on sulfur in the waste gas as it
passes through fluidized reactive particles in a de-sulfurization
column. The second stage receives the exiting gas from stage one
and submits it to a scrubber/separator operation, the resulting
gas exiting to atmosphere and the sulfur containing solids
settling out. Moss recycles the solids separated from the gas as
part of a slurry fed to the fluidized reactive particles.
The applicant provides a two stage treatment to remove sulfur
from waste gas. The first stage, like that in Atomenergie and in
Moss, reacts on waste gas in a fluidized bed to bind sulfur. The
second stage, like that in Moss, provides a scrubber/separator
operation from which the resulting gas passes to atmosphere and
the sulfur containing solids settle out.
We think the Applicant employs part of the Moss system that
achieves additional flue gas desulfurization, in that the
Applicant provides a fluidized bed of particles to act on sulfur
that is part of a flue gas, as does Moss. Both the Applicant and
Moss remove from the fluidized bed, particles that have been
coated due to reaction with the sulfur, and pass them through a
grinder to produce smaller particles having fresh active
surfaces. These smaller particles are then introduced into the
upper part of the fluidized bed where they contact the flue gas.
We note the Applicant has referred to Mico Products Ltd. v Acetol
products Inc. (1930 Ex.C.R. in his response, and we find
direction from the following passages:
It may, however be said that there is even no
invention in a mere adaptation of an idea in a well
known manner for a well known purpose, without
ingenuity, though the adaptation effects an improvement
which may supplant an article already on the market.
A patent for the mere new use of a known
contrivance, without any additional ingenuity in overcoming fresh diffi-
culties, is bad, and cannot be supported. If the new use involves no in-
genuity, but is in manner and purposes analogous to the old use, although
not quite the same, there is no invention.
as said by Lord Lindley, in the case of Gadd and Mason v.
The Mayor, etc. of Manchester (1).
In our opinion, therefore, the Applicant's claim 1 sets forth no
more than the steps disclosed by the Moss patent for obtaining
flue gas desulfurization, namely, withdrawing coarse waste
particles from a fluidized bed, causing them to become finely
divided particles having increased active surfaces, and injecting
the finely divided particles into the fluidized bed so that they
react with the gas. We are persuaded that the Applicant's choice
of a particular fluidized bed does not add any patentable feature
to claim 1. We find claim 1, therefore, not to be patentable in
view of the Moss patent.
We observe that none of the cited patents disclose any means to
collect fine dusts from a desulfurization column and mix them
with the crushed finely divided particles and then introduce the
mix into a fluidized bed, nor to submit the mix of the fine dusts
and the divided particles to a gas/solid contacting device before
injection into a fluidized bed, nor to treat the coarse particles
to steam/water injection. We find the subject matter set forth
in claims 2 to 18 is acceptable in view of the cited patents.
We recommend therefore the rejection of claim 1 be maintained for
being obvious in view of the cited patents, and we recommend that
the rejection of claims 2 to 18 be withdrawn.
M.G. Brown S.D. Kot
Acting Chairman Member
Patent Appeal Board
I have reviewed the prosecution of this application, and I concur
with the findings and the recommendations of the Patent Appeal
Board. Accordingly, I refuse to grant a patent containing claim
1, and I withdraw the rejection of claims 2 to 18. The Applicant
has six months within which to appeal my decision under Section
42 of the Patent Act.
J.H.J. Gari‚py
Commissioner of Patents
Dated at Hull, Quebec
this 10 day of January 1989