Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to apparatus for removing
gaseous components and/or solid impurities from a gaseous fluid flow
and, more particularly, to apparatus incorporating scrubbing means
which serve to wash away any gaseous or solid impurities present in
the gaseous fluid flow.
Gaseous fluid flows frequently contain impurities both in
the forrm of gaseous components and solid particles which must be
removed prior to further processing and use of the fluid flow.
Various apparatus are known by which gaseous fluid flows,
such as coal gas or othcr gases, are wash~d or scrubbed to remove
such impurities. One type of such apparatus includes a frame struc-
ture in which are accommodated an inlet connector through which the
gaseous fluid flow is charged into the apparatus, a discharge con-
nector through which the purified fluid flow is discharged from the
apparatus, scrubber means for washing the gaseous fluid flow and a
connector for conducting a scrubbing liquid into the apparatus so
that the same contacts the gaseous fluid flow.
In prac-tice, the gaseous fluid flow frequently contains
solid impurities in such large quantities that their separation from
the fluid flow before the latter reaches the scrubber means is
desirable~ Thus, it is common under usu~l conditions to purify a
gaseous fluid flow using a wet scrubber wherein the gaseous fluid
Elow is conducted into a frame portion of a separator, i.e., into a
fluid tank or reaction chamber, wherein intimate contact between
the scrubbing liquid and the gaseous fluid flow is attempted to be
maximized. At least part of the coarser fraction of the solid matter
impurities will separate from the gaseous fluid flow during this
scrubbiny phase and remain in the separating tank.
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However, it is most desirable to separate the greater
part of the solid matter impurities from the gaseous fluid flow
prior to the scrubbing phase while in a dry state and attempts
have been made to achieve this action in either a settling chamber
or in a cyclone separator. This technique is advantageous in that
the quantity of solid impurities which are carried into the
scrubbing liquid is minimized so that the amount of sludge which
is created during the scrubbing phase and which must be removed
from the apparatus will be maintained at a minimum. Moreover,
since a blower is usually provided after the scrubber, this tech-
ni~ue also advantageously reduces wear of the blower. A droplet
s~parator generally is provided following the blower and depending
upon the particular application may be constituted by a grille, a
set of gratings, droplet separators of the cyclone separator type,
various rotating and rou~d towers, and the like.
In conventional scrubbers known in the art, the blower
is usually similar to a conventional centrifugal blower. A so-
called disintegrator type blower is also known in the art into
which the gaseous fluid flow with its impurities ~ogether with the
scrubbing liquid are directed. Such designs require a high power
input from a drive and, moreover, the blower is subject to a high
rate of wear.
In scrubbers of the Venturi type, the gaseous fluid flow
together with the impurities contained therein are accelerated in a
Venturi section to obtain a high velocity and at the same time the
scrubbing liquid is introduced into the accelerated fluid flow.
After passing through the Venturi section, the gaseous fluid flow
with a reduced flow velocity is acted upon by a droplet separator
where the impurities will serve as crystallization nuclei.
So-called S-wave scru~bers havc alsobeen utilized in
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connection with the purification of gaseous fluid flows. In such
arrangements, the gaseous fluid flow together with a scrubbing
liquid flows through an S-wave shaped slit to enter into a free
space from where it is directed into a blower. In such arrange-
ments, there is no separate droplet separator, the separation of
droplets taking place in the free space after the S-wave scrubber
and before the blower. However, a risk exists in this arrangement
that supercondensing moisture may be entrained with the gaseous
fluid flow with droplets then being flung outwardly into the sur-
rounding areas.
Reference is made to my copending application Serial No.
409,533 filed August l9, 1982, in which a wet scrubber is disclosed
in which the end section of a tubular fluid flow inlet connector
which is adjacent to the scrubber means has a conical tapered con-
figuration to accelerate the fluid flow through the inlet connector
before the fluid flow is carried to the scrubber means. In this
apparatus, the tubuler inlet connector is provided with openings
or holes which receive the return flow of the scrubbing liquid into
the inlet connector, the openings being situated in the region of
the inlet connector where the fluid flow is not accelerated. The
return flow of the scrubbing liquid within the tubular inlet con-
nector produces a pre-purification of the fluid flow.
The scrubber arrangement described above is not efficient
under all circumstances. In particular, if the fluid flow being
purified contains large quantities of impurities or if the gaseous
fluid flow being purified is very hot, the arrangement disclosed in
application Serial No. 409,533 is not satisfactory. Moreover, this
arrangement has a drawback in that it is necessary to use large
quantities of scrubbing liquid and, as a result, the circulation of
the scrubbing liquid becomes difficult. The quantity of
scrubbing liquid may become so heavily contaminated that its
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circulation is impeded. These difficulties may ultimately
resull~ the gaseous fluid flow not being purified to the
indicated requirements due to the large concentration of the
impurities in the scrubbing liquid.
Moreover, the arrangement disclosed in the above-
identified application cannot be reliably used when it is
desired to accelerate the fluid flow being scrubbed to a very
high velocity since such operation would risk that impurities
present in the circulating scrubbing liquids as it passes
through the apertures in the tubular inlet connectox will be
entrairled in the pure fluid flow.
Accordingly, the present invention provides an
improved apparatus for removing gaseous components and/or solid
impurities from a gaseous fluid flow.
The present invention also provides an improved scrub-
ber apparatus which overcomes the drawbacks of the various known
scrubber arrangements.
The present invention again provides an improved
scrubber apparatus which does not require large quantities of
~0 scrubbing liquid to attain reliable results.
The present invention further provides a new and
improved scrubber apparatus which is well suited for treating
gaseous fluid flows which contain large amounts of impurities
and for very hot gaseous fluid flows.
Briefly, in accordance with the present invention
these and other objects are attained by providing scrubber
apparatus including a pre-purification section and a fine-
purification section in fluid communication therewith and in
which a scrubber device is situated. A first scrubbing liquid
is introduced into contact with
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the gaseous fluid flow in the pre-purification section to pre-
purify the same. The pre-purified gaseous fluid flow is conducted
to the region of the scrubber device and is accelerated as it is
conducted. As the pre-purified gaseous fluid flow is conducted to
the region of the scr~lbber device, a second scrubbing liquid is
introduced into contact therewith.
Numerous advantages are obtained by the present invention.
Only minimal quantities of scrubbing liquid are required yet a high
scrubbing efficiency is attained, even where high energy scrubbers
are not used.
According to the invention, two separate liquid scrubbing
systems are employed. The first scrubbing fluid introduced into
contact with the gaseous fluid flow in the pre-purifying section is
circulated in its own liquid circulation system and may obtain a
concentration of gaseous components and/or solid impurities to a
desired concentration. Since the gaseous fluid flo~ will be ren-
dered exceedingly clean or pure after the pre-purification step,
the second scrubbing liquid which is introduced into contact with
the pre-purified gaseous flow will remain relatively pure, i~e.,
the concentration of impurities in the second scrubbing liquid will
be relatively low, even after relatively long periods and where the
second scrubbing liquid is circulated in its own circulation system.
Moreo~er, the present invention insures that the impurities present
in the first scrubbing liquid will not under any circumstances
become entrained in the gaseous fluid flow which has already been
purified.
DETAILED DESCRIPTION OF THE DRAWINGS
_
A more complete understanding of the present invention and
many of the attendant advantages thereof will be readily appreciated
when the same becomes better understood by reference to the following
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detailed description when considered in connection with the
accompanying drawings in which the sole figure is a schematic side
elevation view in section of an apparatus in accordance with the
invention for practicing the method of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawing, an apparatus for removing
gaseous components and/or solid impurities from a gaseous fluid
flow in accordance with the invention is generally designated 10.
The apparatus 10 includes a pre-purification section 11 and a fine-
purification section 12 in fluid communication therewith. In the
illustrated embodiment, the pre-purification section 11 comprises a
tubular chamber provided with an inlet flow aperture 13 through
which the gaseous fluid flow 14 to be treated enters into the
interiox of the chamber. The gaseous fluid flow 14 is drawn through
the inlet aperture 13 into the tubular chamber of the pre-purifica-
tion section 11 tangentially so that the incoming gaseous fluid flow
14 flows upwardly with a rotary motion within the tubular chamber.
The upper part 15 of the tubular chamber of the pre-
purification section 11 has a conical configuration tapering upwardly
in the direction of the fine-purification section 12 so that the
gaseous fluid flow passing through the upper part 15 will be
accelerated as it flows therethrough. Thus, the upper part 15 of
the tubular chamber of the pre-purification section 11 constitutes
in the illustrated embodiment an outlet through which the gaseous
fluid flow, pre-purified in section 11 as discussed below, is dis-
charged from the pre-purification chamber, as well as means for
accelerating the pre-purified gaseous fluid flow.
A tank 16 is provided with a first scrubbing liquid 17.
A pump 18 is provided to pump the first scrubbinq liquid 17 from the
tank 16 through a tubular connector or conduit 19, the end of which
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extends through the wall defining the chamber of the pre-purifi-
cation section 11 and terminates at a discharge aperture 20, such
as a nozzle or the like. The discharge aperture 20 of the tubular
connector 19 directs the first scrubbing liquid 17 against the
wall of the tubular chamber of pre-purification section 11 so that
the first scrubbing liquid 17 flows in a rotary motion downwardly
in the tubular chamber of section 11. Since the incoming gaseous
fluid flow 14 and the flow of the first scrubbing liquid 17,
designated 21, both have a rotary motion but in opposite directions,
the first scrubbing liquid 17 will efficiently flush the incoming
gaseous fluid flow 14 to remove at least the largest and heaviest
solid impurities therefrom. The first scrubbing liquid 17 and solid
impurities entrained therein run down into the bottom region 22 of
the tubular chamber of section 11 to be conducted back into the
tank 16 as a flow 24 through a valve means 23.
According to an important feature of the invention, a
second scrubbing liquid is introduced into contact with the gaseous
fluid flow which has been pre-purified in the section 11 as des-
cribed above as the pre-purified gaseous fluid flow is accelerated,
i.e., as the pre-purified gaseous fluid flow passes through the
tapered upper part 15 of the chamber of the pre-purification section
11. In the illustrated embodiment, a second tubular connector or
conduit 28 communicates with a tank 25 containing a second scrubbing
liquid 26 and extends through the chamber of the pre-purification
section 11 and terminates at a discharge aperture 29, such as a
nozzle. The discharge aperture 29 of the connector 28 is situated
in the upper part 15 of the pre-purification chamber, i.e., in the
region where the pre-purified gaseous fluid flow is accelerated.
The pump 27 pumps the second scrubbing liquid 26 from the tank 25
through the connector 28 so that the second scrubbing liquid
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discharges from the nozzle or discharge aperture 29 as a flow,
designated 30. ~he second scrubbing liquid 26 may be relatively
pure and different composition from the first scrubbing liquid 17,
although it is understood that the same composition can be used
for both the first and second scrubbing liquids.
Scrubber means, generally designated 32, are situated in
the fine-purification section 12. The scrubber means 32 comprise
a rotatable blade impeller which is driven by an electric motor 33
which is supported by a plate 34 and struts 35.
The upper part 15 of the chamber of the pre-purification
section 11 in which the pre-purified gaseous fluid flow is accel-
erated has its discharge opening situated in the region of and
substantially adjacent to the scrubber means 32 as seen in the
figure. The flow 30 of the second scrubbing liquid discharged
from the aperture or nozzle 29 is admixed into the already pre-
purified gaseous fluid flow 14 to form a total flow, designated 31,
comprising a combination of the already pre-purified gaseous fluid
flow 14 and the flow 30 of the second scrubbing liquid 26. This
total flow 31, already accelerated as it passes through the upper
part 15, is further accelerated to gain additional velocity by means
of the rotation of the impeller of the scrubber means 32.
After passing through the impeller of the scrubber means
32, the total fluid flow 31 is purified in that the liquid droplets
of the second scrubbing liquid 26 are flung against the walls of
the lower part 36 of the fine-purification section 12 from where
they run through the tubular connector or conduit 37 back into the
tank 25. In this manner, the gaseous fluid flow is finely purified
in the fine-purification section 12. The pure gaseous fluid flow,
designated 39, is directed to the top part 38 of the fine-purifica-
tion section 12 and is discharged therefrom through a discharge
aperture 40.
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It wil] be seen that the objects of ~he invention as set
forth above are attained in the rnanner described above. The first
scrubbing liquid 17 may become concentrated to a desired concen-
tration or indeed may become highly supersaturated. The second
scrubbing liquid 26 may be an alkali, even where the first scrubbing
liquid 17 is acidic. This affords the remarkable advantage that
the gaseous fluid flow 14 being purified in the apparatus 10 of
the invention may also be neutralized during the scrubbing opera-
tions. The amount of the second scrubbing liquid 26 with which the
gaseous fluid flow is treated may be considerably less per unit time
than that of the first scrubbing liquid 17 while still achieving
excellent purification of the gaseous fluid flow.
Lower power motors 33 can be used since the second
scrubbing liquid 26 which passes through the impeller of the scrub-
ber means 32 requires little additional acceleration. The nozzle
20 of the conduit 19 for the first scrubbing liquid 17, as well as
the nozzle 29 of the conduit 28 for the second scrubbing liquid 26
may be controlled in various ways so that desired spray effects are
obtained on the walls of the apparatus.
Obviously, numerous modifications and variations of the
present invention are possible in the light of the above teachings.
It is therefore to be understood that within the scope of the claims
appended hereto, the invention may be practiced otherwise than as
specifically disclosed herein.
