U.S. patent number 3,862,907 [Application Number 05/316,012] was granted by the patent office on 1975-01-28 for method for rapidly mixing different kinds of gas.
This patent grant is currently assigned to Nippon Kokan Kabushiki Kaisha. Invention is credited to Yutaka Fukuda, Kazuo Sano, Teruo Shimotsuma.
United States Patent |
3,862,907 |
Shimotsuma , et al. |
January 28, 1975 |
Method for rapidly mixing different kinds of gas
Abstract
A method for rapidly mixing two kinds of gas which comprises
introducing one kind of gas having a higher density than the other
kind of gas into the upper part of a cyclone-type gas mixing
chamber through an upper gas inlet pipe communicating with a hole
bored in the mixing chamber in a tangential direction, and
simultaneously introducing the other kind of gas into the lower
part of said gas mixing chamber through another gas inlet pipe
communicating with a hole formed in the mixing chamber and disposed
in the opposite tangential direction to that in which said upper
gas is swirled in the gas mixing chamber, wherein the vertical
distance between the two gas inlet pipes is 1.5 to 3.0 times the
diameter of the upper gas inlet pipe, the lower gas enters the
mixing chamber at a linear velocity 1.15 to 20.0 times that of the
upper gas, and the upper gas has a vortical flow at a swirling
linear velocity 1.0 to 3.5 times the vertical velocity at which
said gas is gradually brought downward while spirally flowing.
Inventors: |
Shimotsuma; Teruo (Yokohama,
JA), Sano; Kazuo (Yokohama, JA), Fukuda;
Yutaka (Yokohama, JA) |
Assignee: |
Nippon Kokan Kabushiki Kaisha
(Tokyo, JA)
|
Family
ID: |
14376974 |
Appl.
No.: |
05/316,012 |
Filed: |
December 18, 1972 |
Foreign Application Priority Data
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|
|
|
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Dec 22, 1971 [JA] |
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46-104297 |
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Current U.S.
Class: |
252/373;
48/180.1; 48/197FM; 48/197A; 48/197R; 261/79.2; 423/DIG.7 |
Current CPC
Class: |
B01J
19/2405 (20130101); B01F 5/0057 (20130101); B01J
12/00 (20130101); Y10S 423/07 (20130101) |
Current International
Class: |
B01J
19/24 (20060101); B01J 12/00 (20060101); B01F
5/00 (20060101); B01f 003/02 () |
Field of
Search: |
;48/197FM,18M,18R
;261/79A ;137/3,604 ;252/372,373 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bashore; S. Leon
Assistant Examiner: D'Andrea, Jr.; Alfred
Attorney, Agent or Firm: Flynn & Frishauf
Claims
1. A method for rapidly mixing at least two different kinds of
gases which comprises introducing a first gas into the upper part
of a cyclone-type gas mixing chamber having a longitudinal axis
through an upper gas inlet pipe disposed in a tangential direction
to the periphery of said chamber; and simultaneously introducing a
second gas having a lower density than said first gas into the
lower part of said mixing chamber through a lower gas inlet pipe
disposed in a tangential direction to said periphery and in an
opposite gas swirling direction to that of said first gas, both
gases swirling vortically about said longitudinal axis, the
vertical distance between said gas inlets being from 1.5 to 3.0
times the diameter of said upper gas inlet pipe; said second gas
entering said mixing chamber at a linear velocity 1.15 to 20.0
times that at which said first gas enters said mixing chamber; said
first gas supplied to the mixing chamber through the upper gas
inlet pipe having a vortical flow at a swirling linear velocity 1.0
to 3.5 times the vertical velocity at which said gas is gradually
brought downward while spirally flowing; whereby said gases are
mixed, and withdrawing said mixed gas through an outlet positioned
in said
2. A method for rapidly mixing and reacting blast furnace gas with
coke oven gas which comprises introducing blast furnace gas into
the upper part of a cyclone-type gas mixing chamber having a
longitudinal axis through an upper gas inlet pipe in a tangential
direction to the periphery of said chamber; and simultaneously
introducing coke oven gas into the lower part of said mixing
chamber through a lower gas inlet pipe disposed in a tangential
direction to said periphery and in an opposite gas swirling
direction to that of said blast furnace gas; both gases swirling
vortically about said longitudinal axis; the vertical distance
between both gas inlet pipes being from 1.5 to 3.0 times the
diameter of said upper gas inlet pipe; the coke oven gas entering
said mixing chamber at a linear veloctiy 1.15 to 20.0 times that at
which said blast furnace gas enters said mixing chamber; said blast
furnace gas entering said mixing chamber to cause vortical flow at
a swirling linear velocity 1.0 to 3.5 times the vertical velocity
at which said gas is gradually brought downward while spirally
flowing, whereby said gases are mixed, and withdrawing said mixed
gas through an outlet positioned in said mixing chamber below said
lower gas inlet pipe.
Description
This invention relates to a method for mixing different kinds of
gas, and more particularly to a method for rapidly mixing different
kinds of gas to promote reaction therebetween.
Where two kinds of gas are mixed, there has heretofore been used a
cyclone-type gas mixing chamber illustrated in FIGS. 1 and 2 in
order to carry out mixing with higher efficiency. As apparent from
these figures, there is introduced one kind of gas 3 into a
cylindrical mixing chamber 1 through a vertical gas inlet pipe 2
communicating with a hole bored at the top center of said chamber 1
to be dispersed therein, whereas the other kind of gas 5 is brought
into the chamber 1 through a tangential gas inlet pipe 4
communicating with a hole formed in the upper periphery of the
cylindrical mixing chamber 1 for a vortical flow. The gas mixture 8
in the chamber 1 is drawn off through a vertical gas outlet pipe 7
communicating with the bottom opening of a funnel section 6
integrally fitted to the underside of the mixing chamber 1.
Even a cyclone-type gas mixing chamber of the above-mentioned
construction fails to effect the rapid mixing of two kinds of gas.
For uniform mixing, the mixing chamber 1 would have to be
considerably elongated. Further, if the two kinds of gas widely
vary in temperature or density, then there will generally be
presented greater difficulties in attaining homogeneous mixing.
It is accordingly an object of this invention to provide a method
for rapidly mixing different kinds of gas by improving the prior
art cyclone method, using a mixing chamber having even a small
capacity.
Another object of the invention is to provide a method for
attaining the rapid homogeneous mixing of different kinds of gas
widely varying in temperature or density.
These objects can be attained by the method of this invention for
rapidly mixing different kinds of gas, which comprises introducing
one kind of gas having a higher density than another kind of gas
into the upper part of a cyclone-type gas mixing chamber through an
upper gas inlet pipe communicating with a hole bored in said
chamber in a tangential direction; and simultaneously conducting
another kind of gas into the lower part of said chamber through
another lower gas inlet pipe communicating with a hole formed in
said mixing chamber and disposed in a tangential and opposite gas
swirling direction to that of the gas introduced in the chamber
through the upper gas inlet pipe, wherein the vertical distance
between the two gas inlet pipes is from 1.5 to 3.0 times the
diameter of the upper gas inlet pipe; the lighter gas is conducted
through the lower gas inlet pipe at a linear velocity 1.15 to 20.0
times that at which the denser gas is brought into the mixing
chamber through the upper gas inlet pipe; and the denser gas
supplied to the mixing chamber through the upper inlet pipe makes a
vortical flow at a swirling linear velocity 1.0 to 3.5 times the
vertical velocity at which said gas is gradually brought downward
while spirally flowing.
Other important objects and advantageous features of this invention
will be apparent from the following description and accompanying
drawings, wherein, for the present purpose of illustration only,
specific embodiments of this invention are set forth in detail.
In the drawings:
FIG. 1 is an elevational view of a cyclone-type gas mixing chamber
of the prior art;
FIG. 2 is a plan view of FIG. 1;
FIG. 3 is an elevational view of a cyclone-type gas mixing chamber
according to the present invention;
FIG. 4 is a plan view of FIG. 3;
FIG. 5 is an elevational view of a cyclone-type gas mixing chamber
according to another embodiment of the invention;
FIG. 6 is a plan view of FIG. 5;
FIG. 7 is an elevational view of a cyclone-type gas mixing chamber
according to still another embodiment of the invention; and
FIG. 8 is a plan view of FIG. 7.
As previously described, the prior art cyclone-type gas mixing
chamber illustrated in FIGS. 1 and 2 presents difficulties in
effecting the easy homogeneous mixing of two kinds of gas. Unlike
FIGS. 1 and 2, the gas mixing chamber according to the method of
this invention is characterized in that two gas inlet pipes are
fitted to the upper and lower parts of the periphery of a gas
mixing chamber in opposite tangential directions so as to cause the
two kinds of gas brought into the mixing chamber to flow vortically
in opposite directions. In this case, it is required that the
vertical distance between both gas inlet pipes be 1.5 to 3.0 times
the diameter of the upper inlet pipe, and that the denser gas be
carried through the upper pipe. If the distance between both inlet
pipes departs from the above-mentioned range or the lighter gas is
ejected into the chamber through the upper inlet pipe, then the
desired object will not be obtained. Further, it has been
experimentally found that the following two conditions should be
fully met. Namely, the lighter gas should be carried through the
lower gas inlet pipe at a velocity 1.15 to 20.0 times that at which
the denser gas is conducted through the upper gas inlet pipe, and
further said denser gas should make a vortical flow in the mixing
chamber at a swirling linear velocity 1.0 to 3.5 times the vertical
linear velocity at which said gas is gradually brought downward
while spirally flowing. (The ratio of the vortical linear velocity
of the denser gas to its descending velocity is generally referred
to as the swirl ratio.) Unless these two conditions are fully
satisfied, the two kinds of gas could not be homogeneously
mixed.
There will now be described the operation of the cyclone-type
mixing chamber of this invention shown in FIGS. 3 and 4 with all
the aforesaid conditions fully met. Both sides of a cylindrical gas
mixing chamber 11 are fitted with an upper gas inlet pipe 12 and a
lower gas inlet pipe 14 disposed in parallel and in opposite
tangential directions, with the vertical distance between both
pipes 12 and 14 chosen to be 1.5 to 3.0 times the diameter of the
upper gas inlet pipe 12. when introduced into the gas mixing
chamber 11 through the upper inlet pipe 12, the denser gas 13 is
gradually brought downward while making a vortical flow along the
inner wall of the mixing chamber 11. On the other hand, the lighter
gas 15 conducted into the gas mixing chamber 11 through the lower
inlet pipe 14 makes an opposite vortical flow to the denser gas 13
and vigorously strikes against said denser gas 13 descending from
above while spirally flowing, thus effecting rapid mixing.
In FIGS. 3 and 4, the two gas inlet pipes 12 and 14 are fitted to
the mixing chamber 11 in opposite tangential directions. However,
provided the two kinds of gas brought into the mixing chamber 11
flow vortically in opposite directions, the two horizontal gas
inlet pipes may define any desired angle. This condition is
exemplified in FIGS. 5 and 6. Namely, the two horizontal gas inlet
pipes 22 and 24 are fitted to the same side of the gas mixing
chamber in the same vertical plane and in opposite tangential
directions, defining an angle of 180.degree.. Where there are
rapidly mixed three or more kinds of gas, the densest kind of gas
is introduced into the mixing chamber through the upper inlet pipe,
and the remaining lighter kinds of gas may be conducted into the
mixing chamber through a lower inlet pipe system consisting of a
plurality of component pipes which are fitted to the mixing chamber
in the same level and in such tangential direction as causes the
lighter kinds of gas carried therethrough to make an opposite
vortical flow to the descent kinds of gas.
FIGS. 7 and 8 show a gas mixing chamber for mixing five kinds of
gas. The densest kind of gas is carried into the mixing chamber
through an upper gas inlet pipe 32. The other four lighter kinds of
gas are brought into the mixing chamber through lower gas inlet
pipes 34a, 34b, 34c and 34d respectively so as to make an opposite
vortical flow to the densest kind of gas taken into the mixing
chamber through the upper inlet pipe 32. In this case, too, the
previously mentioned conditions should be followed, excepting that
said four lighter kinds of gas introduced into the mixing chamber
through the lower inlet pipes 34a, 34b, 34c and 34d should make a
vortical flow at a mean velocity 1.15 to 20.0 times that at which
the densest kind of gas brought into the mixing chamber through the
upper inlet pipe 32 makes an opposite vortical flow. This modified
process attains the rapid mixing of several kinds of gas.
The gas mixing chamber of FIGS. 7 and 8 provided with a plurality
of gas inlet pipes is not only adapted to mix several kinds of gas,
but also has the advantage of facilitating the quick mixing of two
kinds of gas widely varying in density which has heretofore been
considered appreciably difficult, by introducing the lighter gas
into the mixing chamber uniformly through a plurality of lower gas
inlet pipes.
The method of the invention not only attains the rapid mixing of
two or more kinds of gas independently of their temperature, but
also quickly completes the chemical reactions which would accompany
said mixing in a mixing chamber having even a small capacity.
There will now be described, for example, the case where there is
prepared reducing gas used in the operation of a blast furnace by
mixing blast furnace gas at a temperature of 1250.degree.C with
coke oven gas at 700.degree.C.
Mixing of both kinds of gas gives rise to the following
reactions:
CH.sub.4 .fwdarw. 2H.sub.2 + C
C + CO.sub.2 .fwdarw. 2CO
When mixed by the method of this invention, both kinds of gas
quickly react with each other, decreasing the content of free
carbon and increasing that of CO in the produced gas. Imperfect
mixing of both kinds of gas would cause unreacted CH.sub.4 and
CO.sub.2 to remain in the gas mixture, probably giving rise to
larger carbon loss in attaining the reducing effect for blast
furnace operation.
The above-mentioned two kinds of gas were mixed in a cyclone-type
gas mixing chamber shown in FIGS. 5 and 6. In this case, the denser
blast furnace gas was taken into a cyclone-type gas mixing chamber
through the upper gas inlet pipe 22 and the lighter coke oven gas
into said mixing chamber through the lower inlet pipe 24. The blast
furnace gas had a density 2.75 times that of the coke oven gas. The
value of swirl ratio of the introduced denser gas was 1.8. Table 1
below presents the compositions of gas mixtures obtained from the
mixing chamber by varying the ratio of the velocity Vc at which the
coke oven gas was ejected from the lower inlet pipe 24 to the
velocity Vb at which the blast furnace gas was supplied from the
upper inlet pipe 22.
Table 1 ______________________________________ Composition of gas
mixture obtained from the gas mixing chamber (% by volume)
______________________________________ Value of Vc/Vb Component 1.0
1.2 1.5 2.0 ______________________________________ CO.sub.2 12 9 1
<1 CO 28 31 39 41 H.sub.2 26 39 37 38 N.sub.2 21 21 21 21
CH.sub.4 13 10 2 0 ______________________________________
As clearly seen from Table 1 above, where the value of Vc/Vb was
1.0, mixing was carried out insufficiently, leaving a large amount
of CH.sub.4 and CO.sub.2, and where said value was larger than 1.2,
content of CH.sub.4 and CO.sub.2 prominently decreased. When the
value of Vc/Vb reached 2.0, mixing and reaction were fully
effected, substantially eliminating CH.sub.4 and CO.sub.2.
Further, the blast furnace gas and the coke oven gas were mixed in
the present mixing apparatus by varying the swirl ratio in the
range of from 0.8 to 3.8 with the value of the aforesaid Vc to Vb
ratio kept at 1.5, the compositions of the resulting gas mixtures
are presented in Table 2 below.
Table 2 ______________________________________ Composition of gas
mixture obtained from the mixing chamber (% by volume)
______________________________________ Value of swirl ratio
Component 0.8 1.0 2.6 3.5 3.8
______________________________________ CO.sub.2 3 <1 <1 1 1
CO 36 39 40 40 40 H.sub.2 30 37 38 37 36 N.sub.2 21 21 21 21 21
CH.sub.4 10 2 <1 1 2 ______________________________________
As apparent from Table 2 above, where the value of swirl ratio was
smaller than 1.0, the content of CH.sub.4 and CO.sub.2 in the gas
mixture noticeably increased. Where the value of swirl ratio was in
the range of from 1.0 to 3.5, there was almost no CH.sub.4 and
CO.sub.2, and when the value exceeding 3.5, the content of CH.sub.4
rather tended to rise.
* * * * *