Note: Descriptions are shown in the official language in which they were submitted.
~0536~7
BACKGROUND OF THE INVENTION
This invention relates to electrolytic cells suited for the
electrolysis of aqueous solutions. More particularly, this invention
relates to electrolytic cells suited for the electrolysis of aqueous
alkali metal chloride solutions.
Electrolytic cells have been used extensively for many years
for the production of chlorine, chlorates, chlorites, hydrochloric
acid, caustic, hydrogen and other related chemicals. Over the years,
such cells have been developed to a degree whereby high operating
efficiencies have been obtained, based on the electricity expended.
Operating efficiencies include current, decomposition, energy, power
and voltage efficiencies. The most recent developments in electrolytic
cells have been in making improvements for increasing the production
capacities of the individual cells while maintaining high operating
efficiencies. This has been done to a large extent by modifying or
redesigning the individual cells and increasing the current capacities
at which the individual cells operate. The increased production
capacities of the individual cells operating at higher current cap-
acities provide higher production rates for given cell room floor
areas and reduce capital investment and operating costs.
In general, the most recent developments in electrolytic cells
have been towards larger cells which have high production capacities
and which are designed to operate at high current capacities while
maintaining high operating efficiencies. Within certain operating
parameters, the higher the current capacity at which a cell is designed
to operate, the higher is the production capacity of the cell. As the
designed current capacity of a cell is increased, however, it is im-
portant that high operating efficiencies be maintained. Mere enlargement
of the component parts of a cell designed to operate at low current
capacity and will not provide a cell which can be operated at high
current capacity and still maintain high operating efficiencies.
-- 2 --
~05;~607
Numerous design improvements must be incorporated into a high current
capacity cell so that high operating efficiencies can be maintained
and high production capacity can be provided.
The electrolytic cell of the present invention may be adapted
to be used as different types of electrolytic cells of which chlor-
alkali cells are of primary importance. The electrolytic cell of the
present invention will be described more particularly with respect to
chlor-alkali cells and most particularly with respect to chlor-alkali
diaphragm cells. However, such descriptions are not to be understood
as limiting the usefulness of the electrolytic cell of the present
invention with respect to other types of electrolytic cells.
In the early prior art, chlor-alkali diaphragm cells were
designed to operate at relatively low current capacities of about
10,000 amperes or less and had cQrrespondingly low production capacities.
Typical of such cells is the Hooker Type S Cell, developed by the
Hooker Chemical Corporation, Niagara Falls, New York, U.S.A., which was
a major breakthrough in the electrochemical art at its time of develop-
ment and initial use. The Hooker Type S Cell was subsequently improved
by Hooker in a series of Type S Cells such as the Type S-3, S-3A, S-3B,
S-3C, and S-3D and S-4, whereby the improved cells were designed to
operate at progressively higher current capacities of about 15,000,
20,000, 25,000, 30,000, and 40,000 and upward to about 55,000 amperes
with correspondingly higher production capacities. The design and per-
formance of these Hooker Type S cells are discussed in Shreve, Chemical
Process Industries, Third Edition, Pg. 233 (1967~, McGraw-Hilli Mantell,
Indust al Electrochemistry, Third Edition, Pg. 434 (1950), McGraw-Hilli
and Sconce, Chlorine, Its Manufacture, Properties and Uses, A.C.S.
Monograph, Pp. 94-97 (1962), Reinhold. U.S. Patent 2,987,463 by Baker
1053607
et al. issued June 6, 1961 to Diamond Alkali discloses a chlor-alkali
diaphragm cell designed to operate at a current capacity of about
30,000 amperes which is somewhat different than the Hooker Type S
series cell. U.S. Patents 3,464,912 by Emery et al. issued Sept. 2,
1969 to Hooker and 3,493,487 by Currey et al. issued Nov. 2, 1971 to
Hooker disclose chlor-alkali diaphragm cells designed to operate at
a current capacity of about 60,000 amperes.
The above description of the prior art shows the development
of chlor-alkali diaphragm cell design to provide cells which operate at
higher current capacities with correspondingly higher production capa-
cities. Chlor-alkali diaphragm cells have now been developed which
operate at high current capacities of about 150,000 amperes and upward
to about 200,000 amperes with correspondingly higher production capa-
cities while maintaining high operating efficiencies.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided
a novel electrolytic cell. The novel electrolytic cell comprises a
novel cathode busbar structure, novel cathode fingers having a novel
cathode finger structure, and a novel anode base structure.
The novel cathode busbar structure comprises at least one lead-
in busbar and a plurality of busbar strips which have different relative
dimensions. The lead-in busbar or busbars and the plurality of busbar
strips are fabricated from a highly conductive metal and are positioned
in such a configuration wherein the lead-in busbar or busbars and the
plurality of busbar strips are adapted to carry an electric current
and to maintain a substantially uniform current density through the
cathode busbar structure to electrical contact points adjacent to the
cathode fingers without any significant voltage drop across the cathode
busbar structure and with the most economical power consumption in the
cathode busbar structure. The cathode busbar structure is attached to
10536(37 ~'
at least one sidewall of a cathode walled enclosure. The cathode
walled enclosure contains a plurality of cathode fingers which extend
substantially across the interior of the cathode walled enclosure and
the cathode fingers are attached in electrical contact to at least one
interior sidewall of the cathode walled enclosure. The cathode busbar
structure is attached in electrical contact to the exterior sidewall of
the cathode walled enclosure adjacent to the attached cathode fingers.
The novel cathode busbar structure makes the most economic
use of invested capital, namely, the amount of highly conductive metal
used in the cathode busbar structure. The configuration and different
relative dimensions of the lead-in busbar or busbars and the plurality
of busbar strips significantly reduce the amount of highly conductive
metal required in the cathode busbar structure as compared to the prior
art. The lead-in busbar or busbars and the plurality of busbar strips
by means of their configuration and different relative dimensions are
a1so adapted to carry an electric current and to maintain a substantially
uniform current density through the cathode busbar structure. ~ -
The novel cathode busbar structure can be provided with means
for attaching cathode jumper connector means when an adjacent electro-
lytic cell is jumpered and is removed from the electrical circuit. The
cathode busbar structure can also be provided with cooling means to
prevent temperatures in the cathode busbar structure from rising to
damaging levels and to further reduce the amount of highly conductive
metal required in the cathode busbar structure. -
The novel cathode finger structure comprises a conductive
metal cathode finger reinforcing means, lengths of highly conductive
metal positioned in the cathode finger structure and foraminous con-
ductive metal means attached to the cathode finger reinforcing means
thereby forming the exterior of the cathode finger structure and gas
-- 5 --
10536~7
compartment space ins;de the cathode finger structure. The cathode
finger reinforcing means can be provided with a suitable number of pegs,
pins or protrusions. The foraminous conductive metal means can be attach-
ed to these protrusions and thereby provide additional compartment space
for gas, formed at the cathode during electrolysis, to be channeled to a
collection chamber.
The highly conductive metal is preferably positioned on the
cathode finger reinforcing means in the cathode finger structure and
means is provided for attaching the highly conductive metal to the
cathode finger reinforcing means. The highly conductive metal is po-
sitioned in the cathode finger structure in such a configuration whereby
the lengths of highly conductive metal are adapted to carry an electric
current and to maintain a substantially uniform current density through
the cathode finger structure without any significant voltage drop
across the cathode finger structure and with the most economical power
consumption in the cathode finger structure.
The novel cathode finger structure provides novel cathode
fingers. The cathode walled enclosure contains a plurality of cathode
fingers which extend substantially across the interior of the cathode
walled enclosure and the cathode fingers are attached in electrical
contact to at least one interior sidewall of the cathode walled en-
closure. The cathode busbar structure is attached in electrical contact
to the exterior sidewall of the cathode walled enclosure adjacent to
the attached cathode fingers.
Means are provided for positioning the opposite ends of the
cathode fingers adjacent to the interior sidewall of the cathode walled
enclosure which is opposite to the interior sidewall where the cathode
fingers are attached.
The novel anode base structure comprises a highly conductive
metal means having a substantially flat and level surface and having a
-, -- ... .
.. . .
10536~7
decreased cross-section as it extends away from the anode or intercell
connecting busbar means to form the cross-sectional shape of a sub-
stantially stair-stepped truncated right triangle. The highly conductive
metal means can be a solid metal plate having a configuration as described
above or can be two or more highly conductive metal shapes, such as plates,
having different relative dimensions and positioned in such a configuration
whereby their cross-sections form the cross-sectional shape of a sub-
stantially stair-stepped truncated right triangle as described above.
The highly conductive metal means can be provided with means for attach-
ing the anode blades. The highly conductive metal means has differentrelative dimensions and such a configuration whereby it is adapted to
carry an electric current and to maintain a substantially uniform
current density through the anode base structure to electrical contact
points adjacent to the anode bladbs without any ~ignif$~t ~ltage drop
across the anode base structure and with the most economical power con- ~`
sumption in the anode base structure.
The novel anode base structure can also comprise suitable ~ -
structural support means for the highly conductive metal means and any
other suitable structural support means to provide the anode base structure
with sufficient means to support other components of the novel electro-
lytic cell of the present invention.
U.S. Patent 3,432,422 by Currey issued Mar. 11, 1969 is herein
cited to show a state of the prior art.
The anode base structure makes the most economic use of
invested capital, namely, the amount of highly conductive metal used in
the anode base structure. The configuration and different relative
dimensions of the highly conductive metal means significantly reduce
the amount of highly conductive metal required in the anode base structure
as compared to the prior art. The highly conductive metal means by
means of its configuration and different relative dimensions is also
. . .
,
,
1053607
adapted to carry an electric current and to maintain a substantially
uniform current density through the anode base structure.
The anode base structure can be provided with an anode ju~per
busbar for attaching anode connector means when an adjacent electrolytic
cell is jumpered and removed from the circuit. The anode base structure
can also be provided with a cooling means to prevent temperatures in the
anode base structure from rising to damaging levels and to further reduce
the amount of highly conductive metal used in the anode base structure.
The novel electrolytic cell of the present invention may be
used in many different electrolytic processes. The electrolysis of
aqueous alkali metal chloride solutions is of primary importance and the
electrolytic cell of the present invention will be described more parti-
cularly with respect to this type of process. However, such description
is not intended to be understood as limiting the usefulness of the
electrolytic cell of the present invention or any of the claims covering
the electrolytic cell of the present invention.
- DESCRIPTION OF THE DRAWINGS
The present invention will be more fully described by reference
to the drawings in which:
FIGURE 1 is an elevation view of a typical electrolytic cell
of the present invention and shows a typical cathode busbar structure;
FIGURE 2 is an enlarged partial sectional side elevation view
of the cell of FIGURE 1 along plane 2-2 and shows another view of the
cathode busbar structure;
FIGURE 3 is an enlarged partial plan view of the cathode
walled enclosure of the cell of FIGURE 1 and shows the relative position
of the cathode iingers;
FIGURE 4 is an enlarged partial sectional and elevation view
of the cathode fingers and the cathode walled enclosure of the cell of
FIGURE 3 along plane 4-4 and shows the relative position of the cathode
,. -: . , ~
lOS3t;07
fingers and anode blades as positioned at the end of the cathode walled
enclosure;
FIGURE 5 is an enlarged sectional side elevation view of a
cathode finger and the cathode walled enclosure of the cell of FIGURE 3
along plane 5-5 and shows the configuration of the highly conductive metal
positioned on the cathode finger reinforcing means;
FIGURE 6 is a side elevation view of the opposite side of the
cathode finger reinforcing means of FIGURE 5 and shows the visible con-
figuration of the highly conductive metal positioned thereon;
FIGURE 7 is a side elevation view of another embodiment of
a cathode finger reinforcing means and shows the configuration of the
highly conductive metal positioned thereon;
FIGURE 8 is an end elevational view of the cathode finger re-
. .... - . .
inforcing means of FIGURE 7 along plane 8-8 and shows the configuration
of the highly conductive metal positioned thereon and the peg or pin means;
FIGURES 3, 4, 5, 6, 7 and 8, when viewed together, show typical
embodiments of cathode finger structures;
FIGURE 9 is a plan view of an anode base structure which can be
used in the cell of FIGURE 1. The anode blades are not shown for clarity;
FIGURE 10 is a side elevation view of the anode base structure
of FIGURE 9 along plane 10-10 and shows the highly conductive metal plate
configuration detail;
FIGURE 11 is a view of FIGURE 10 showing the addition of a
structural cell base support means;
FIGURE 12 is a plan view of an anode base structure which can
be used ~n the cell of FIGURE 1. The anode blades are not shown for
clarity;
FIGURE 13 is a side elevation view of the anode base structure
of FIGURE 12 along plane 13-13 and shows the highly conductive metal plate
configuratiion detail; and
, .
1053607
FIGURE 14 is a view of FIGURE 13 showing the addition of a
structural cell base support means.
The different types of metals are used to fabricate most of
the various components or parts which comprise the novel electrolytic
cell of the present invention. One of these types of metals is a highly
conductive metal. The other type of metal is a conductive metal which
has good strength and structural properties.
The term highly conductive metal is herein defined as a metal
which has a low resistance to the flow of electric current and which is
an excellent conductor of electric current. Suitable highly conductive
metals include copper, aluminum, silver and the like and alloys thereof.
The preferred highly conductive metal is copper or any of its highly
conductive alloys and any mention of copper in this application is to be
interpreted to mean that any other suitable highly conductive metal can
be used in the place of copper or any of its highly conductive alloys
where it is feasible or practical.
The term conductive metal is herein defined as a metal which
has a moderate resistance to the flow of electric current but which is
still a reasonably good conductor of electric current. The conductive
metal, in addition, has good strength and structural properties. Suitable
conductive metals include iron, steel, nickel and the like and alloys
- thereof such as stainless steel and other chromium steels, nickel steels
and the like. The preferred conductive metal is a relatively inexpensive
low-carbon stee1, hereinafter referred to simply as steel, and any mention
of steel in this application is to be interpreted to mean that any other
sùitàble conductive metal can be used in the place of steel where it is
feasible or practical.
The highly conductive metal and the conductive metal should
have adequate resistance to or have adequate protection from corrosion
during operation of the electrolytic cell.
- 10 -
1053~7
Referring now to FIGURE 1, electrolytic cell 11 comprises
corrosion resistant plastic top 12, cathode walled enclosure 13 and cell
base 14. Top 12 is positioned on cathode walled enclosure 13 and is
secured to cathode walled enclosure 13 by fastening means (not shown).
A seal is maintained between top 12 and cathode walled enclosure 13 by
means of a sealing gasket. Cathode walled enclosure 13 is positioned on
cell base 14 and is secured to cell base 14 by fastening means (not shownJ.
A seal is maintained between cathode walled enclosure 13 and cell base 14
by means of an elastomeric sealing pad. Electrolytic cell 11 is positioned
on legs 15 which are used as support means for the cell.
Cathode busbar structure 16 is attached in any suitable manner,
as by welding, to steel sidewall 17 of steel cathode walled enclosure 13.
Cathode busbar structure 16 comprises copper lead-in busbar 18 and a
plurality of copper busbar strips 19, 21 and 22 which have different
relative dimensions and are positioned in such a configuration wherein
lead-in busbar 18 and busbar strips 19, 21 and 22 are adapted to carry
an electric current and to maintain a substantially uniform current
density through cathode busbar structure 16 to electrical contact points
on sidewall 17 of cathode walled enclosure 13.
Cathode busbar structure 16 can be provided with cooling means
23 which comprises steel plates 24, 25, 26 and 30 and steel entrance and
exit ports 27 and 28 fabricated in any suitàble manner, as by welding,
to form the said cooling means. Cooling means 23 is attached in any
suitable manner, as by welding, to lead-in busbar 18 and busbar strip 19.
Coolant, preferably water, is circulated through cooling means 23 by
passage through entrance and exit ports 27 and 28. Cooling means 23 is
provided primarily for use when an electrolytic cell adjacent to electro-
lytic cell 11 is jumpered and is removed from the electrical clrcuit.
The use of cooling means 23 permits considerably less copper to be used
.",.
1053~;07 ~
in cathode busbar structure 16 which results in a substantial reduction
in capital investment costs for cathode copper. While cooling means 23
is provided primarily for use when an electrolytic cell adjacent to
electrolytic cell 11 is jumpered, cooling means 23 can be used during
routine cell operation either to cool cathode busbar structure 16 during
any periodic electric current overloads or to continuously cool cathode
busbar structure 16, thereby permitting further reductions in the use
of copper in cathode busbar structure 16 with an accompanying reduction
in capital investment costs for cathode copper.
- Lead-in busbar 18 can be provided with steel contact plates
29 and 31 which serve as contact means. Steel contact plates 29 and
31 are attached to lead-in busbar 18 in any suitable manner, as by means
of screws 32. Lead-in busbar 18 and steel contact plates 29 and 31 can
be provided with holes 33 which can serve as means for attaching intercell
connectors carrying electricity from an adjacent cell or leads carrying
electricity from another source to lead-in busbar 18. Lead-in busbar 18
and busbar strip 19 can be used as a cathode jumper busbar when provided
with holes 34 which can serve as means for attaching cathode jumper
connectors when an adjacent electrolytic cell is jumpered and is removed
from the electrical circuit. It is during this jumpering operation that
cooling means 23 can provide its greatest utility by preventing the
temperatures in cathode busbar structure 16 from rising to levels whereby
damage to cathode busbar structure 16 or other components of electrolytic
cell 11 occurs.
Referring now to FIGURE 2, cathode busbar structure 16 is
shown in another view and the description of this figure further des-
cribes cathode busbar structure 16 including the configuration and the
different relative dimensions of the components or parts comprising
cathode busbar structure 16 which were described in FIGURE 1.
- 12 -
~LO 5;3~;O 7
Cathode busbar structure 16 comprises copper lead-in busbar
18 and a plurality of copper busbar strips 19, 21 and 22. Busbar strips
19, 21 and 22 are attached to steel sidewall 17 of steel cathode walled
enclosure 13 in any suitable manner, as by means of copper to steel welds
35, 37, 38 and 41, and to one another in any suitable manner, as by means
of copper to copper welds 36 and 39. The weld metal is preferably of the
same metal as the busbar str;ps, that is, copper. This means of attaching
the busbar strips to sidewall 17 greatly decreases the required weld area
and forms a lower electrical contact resistance to sidewall 17 or the
cathode steel. Lead-in busbar 18 is attached to busbar strip 19 in any
suitable manner, as by means of copper to copper weld 42, and lead-in
busbar 18 is attached to sidewall 17 in any suitable manner, as by means
of steel blocks 43. Lead-in busbar 18 is attached to steel blocks 43 in
any suitable manner, as by a combination of screws (not shown), and steel
blocks 43 are attached to sidewall 17 of cathode walled enclosure 13 in
any suitable manner, as by means of steel to steel welds 40. Steel con-
tact plates 29 and 31 are attached to lead-in busbar 18 in any suitable
manner, as by means of screws 32.
The above means of attachment provides a cathode busbar structure
wherein lead-in busbar 18 and the plurality of busbar strips 19, 21 and
22 are attached and electrically interconnected by means of welds 36, 37,
38, 39 and 42 and cathode busbar structure 16 is attached in electrical
contact to sidewall 17 of cathode walled enclosure 13 by means of welds
35, 37, 38, 40 and 41.
Cathode fingers 44 are attached in electrical contact to sidewall
17 in any suitable manner, as by welding cathode finger reinforcing means
45 to sidewall 17. A typical cathode finger 44 is partially shown.
Cathode finger 44 comprises steel cathode finger reinforcing means 45 and
perforated steel plates 46 which are attached in any suitable manner, as
10536(~7
by welding. Perforated steel plates 47 are attached in any suitable
manner, as by welding, to perforated steel plates 46 and sidewall 17,
thereby forming peripheral chamber 48.
The height of the plurality of the busbar strips at their
points of attachment to sidewall 17 is usually substantially equal to
the height of cathode finger reinforcing means 45 at their points of
attachment to sidewall 17. This he;ght can be further defined as being
of more than about one-half of the height of cathode walled enclosure
13. The thickness of busbar strips 21 and 22 are preferably less than
those of lead-in busbar 18 and busbar strip 19.
The cathode finger reinforcing means are preferably corrugated
structures fabricated from conductive steel sheet, however, other suitable
reinforcing means such as conductive metal bars, plates, reinforced sheets
and the like can also be used. The cathode finger reinforcing means serve
the dual functions of first, supporting and reinforcing the perforated
steel plates, and second, carrying electric current to all sections of the
perforated steel plates with a minimum electrical resistance through the
cathode finger reinforcing means.
The foraminous conductive metal means used to form the cathode
fingers and the peripheral chamber are preferably perforated steel plates
but can be steel screens. Other suitable foraminous conductive metal
means which can be used to form the cathode fingers and the peripheral
chamber include conductive metal grids, meshes, screens, wire cloth or
the like.
Cathode walled enclosure 13 is positioned on cell base 14 and
is secured to cell base 14 by fastening means (not shown). Cell base 14
comprises elastomeric sealing pad 49 and conductive anode base 51, and,
if needed, structural support means 52. A seal is maintained between
cathode walled enclosure 13 and cell base 14 by means of elastomeric
sealing pad 49.
- 14 -
1053607
In a typical circuit of electrolytic cells, electric current
is carried through intercell connectors (not shown) to lead-in busbar
18 of cathode busbar structure 16. Electric current is then carried
and a substantially uniform current density is maintained through cathode
busbar structure 16 without any significant voltage drop across cathode
busbar structure 16 and with the most economical power consumption in
cathode busbar structure 16. Electric current is carried and a sub-
stantially uniform current density is maintained through cathode busbar
structure 16 by means of the configuration and the different relative
dimension of lead-in busbar 18 and busbar strips 19, 21 and 22. Electric
current is thus carried through cathode busbar structure 16 to electrical
contact points on sidewall 17 of cathode walled enclosure 13 where it is
distributed to cathode fingers 44 and, under these conditions, the
electric current is readily carried to all sections of perforated steel
plates 46 with a minimum electrical resistance through cathode finger
reinforcing means 45.
The novel cathode busbar structure makes the most economic use
of invested capital, namely, the amount of copper or other suitable highly
conductive metal used in the cathode busbar structure. The configuration
and different relative dimensions of the lead-in busbar or busbars and
the plurality of busbar strips significantly reduce the amount of copper
or other suitable highly conductive metal required in the cathode busbar
structure as compared to the prior art. The lead-in busbar or busbars
and the plurality of busbar strips by means of their configuration and
different relative dimensions are also adapted to carry an electric
current and to maintain a substantially uniform current density through
the cathode busbar structure.
The configuration and dimensions of the lead-in busbar or
busbars and the plurality of busbar strips can vary depending on the
- - 15 -
1053~07
designed current capacity of the electrolytic cell and also can vary
depending on a number of factors such as the current density, the con-
ductivity of the metal used, the amount of weld area, the fabrication
costs and the like.
The novel cathode busbar structure provides improved elect-
rical conductivity to the immediate area of the cathode fingers, thereby
provid~ng a minimum or no significant voltage drop across the cathode
busbar structure with a substantial reduction in copper or other suitable
highly conductive metal expenditures as compared to the prior art.
The novel cathode busbar structure enables the electrolytic cell
of the present invention to be designed to operate as a chlor-alkali
- diaphragm cell at high current capacities of about 150,000 amperes and
upward to about 200,000 amperes while maintaining high operating effi-
ciencies. These high current capacities provide for high production
capacities which result in high production rates for given cell room
floor areas and reduce capital investment and operating costs. In addi-
tion to being capable of operation at high amperages, the electrolytic
cell of the present invention can also efficiently operate at lower
amperages, such as about 55,000 amperes using the novel cathode busbar
structure.
Referring now to FIGURE 3, cathode fingers 44 are enclosed
by steel sidewalls 17, 54, 55 and 56 of steel cathode walled enclosure
13. The plurality of cathode fingers 44 can be any number from about 10
` to about 50 or more, preferably the number is about 15 to about 40 and
more preferably the number is about 20 to about 30. The anode blades
(not shown) are positioned between cathode fingers 44. Perforated steel
plates 46 are attached in any suitable manner, as be welding, to steel
cathode finger reinforcing means 45. Steel plates 53 are also attached
in any suitable manner, as by welding, to cathode finger reinforcing
- 16 -
. : .
1053~ 7
means 45. Cathode fingers 44 are attached to steel sidewall 17 in any
suitable manner, as by welding steel plates 53 and cathode finger re-
inforcing means 45 to sidewall 17. Perforated steel plates 47 are
attached to sidewalls 17, 54, 55 and 56 and to perforated steel plates
46 in any suitable manner, as by welding. Perforated steel plates 47
surround the inner sidewalls of cathode walled enclosure 13 and form
peripheral chamber 48 which serves as a collection chamber for hydrogen
gas formed at the cathode during electrolysis. Hydrogen gas formed at
the cathode during electrolysis is channeled across cathode fingers 44
to peripheral chamber 48 from whence it proceeds to gas withdrawal means
57.
Referring now to FIGURE 4, perforated steel plates 46 are
attached in any suitable manner, as by welding, to steel cathode finger
reinforcing means 45. Steel plates 53 are attached in any suitable
manner, as by welding, to cathode finger reinforcing means 45. Steel
support means 58 are attached in any suitable manner, as by welding, to
cathode finger reinforcing means 45 and to sidewall 56 of steel cathode
walled enclosure 13. Perforated steel plates 47 are attached in any
suitable manner, as by welding, to perforated steel plates 46 and to
sidewalls 17 and 56 thereby forming peripheral chamber 48. Because of
the larger dimensions of this figure, peripheral chamber 48 is more
clearly shown. Cathode finger reinforcing means 45 can be provided
with protrusions 59 and perforated steel plates 46 can be attached in any
suitable manner, as by welding, to protrusions 59 thereby providing
additional compartment space for hydrogen gas, formed at the cathode
during electrolysis, to be channeled to peripheral chamber 48.
Steel tips 61 and steel plates 53 are attached in any suitable
manner, as by welding, to copper rods 62. Steel tips 61 and steel plates
53 are attached in any suitable manner, as by welding, to cathode finger
- 17 _
~()53607
reinforcing means 45 thereby positioning copper rods 62 on cathode
finger reinforcing means 45.
Cathode finger reinforcing means 45 are preferably corrugated
structures fabricated from sheet steel, however, other suitable reinforcing
means such as bars, plates, reinforced sheets and the like can also be
used. Cathode finger reinforcing means 45 serve the dual functions of
first, supporting and reinforcing perforated steel plates 46, and second,
carrying electric current to all sections of perforated steel plates 46
with a minimum electrical resistance through cathode finger reinforcing
means 45.
Referring now to FIGURES 2 and 4, cathode walled enclosure 13
is positioned on cell base 14 and is secured to cell base 14 by fastening
means (not shown). Cell base 14 comprises conductive anode base 51 and,
if needed, suitable structural support means 52. A seal is maintained
between cathode walled enclosure 13 and cell base 14 by means of elasto-
meric sealing pad 49.
Anode blades 72 are preferably metallic anode blades and are
attached in electrical contact to conductive anode base 51 in any suitable
manner, as by means of nuts and/or bolts, secured projections, studs,
welding or the like. Cathode fingers 44 are spaced adjacent to each
other at such a distance whereby anode blades 72 are centered between
adjacent cathode fingers 44 and the desired alignment distance between
anode blades 72 and cathode fingers 44 is provided.
Referring now to FIGURES 2, 3 and 4, electrolytic cell 11 is
particularly useful for the electrolysis of alkali metal chloride solutions
in general, including not only sodium chloride, but also potassium chloride,
lithium chloride, rubidium chloride and cesium chloride. When electro-
lytic cell 11 is used to electrolyze such solutions, electrolytic cell 11
is provided with diaphragm 71 which serves to form separate anolyte and
'
105;~;07
catholyte compartments so that chlorine is formed at the anode and
caustic and hydrogen are formed at the cathode. Diaphragm 71 comprises
a fluid-permeable and halogen-resistant material which covers steel
plates 46 forming cathode fingers 44 and perforated steel plates 47
forming peripheral chamber 48. Preferably, diaphragm 71 is asbestos
fiber deposited in place on the outer surfaces of perforated steel plates
46 and 47. Electrolytic cell 11 is adapted to permit the use of many
types of diaphragms, including asbestos fabric, asbestos paper, asbestos
sheet and other suitable materials known to those skilled in the art.
Perforated steel plates 46 forming cathode fingers 44 and per-
forated steel plates 47 forming peripheral chamber 48 are foraminous
conductive metal means. Other suitable foraminous conductive metal means
which can be used to form the cathode fingers and the peripheral chamber
include conductive metal grids, meshes, screens, wire cloths or the like.
Referring now to FIGURES 3 and 5, some of the details described
in the foregoing figures are more clearly shown in these figures. Cathode
busbar structure 16 is attached to outer sidewall 17 of cathode walled
enclosure 13 and the ends of cathode fingers 44 adjacent thereto are
attached to inner sidewall 17 of cathode walled enclosure 13 in a manner
or manners described in the foregoing figures.
The other ends of cathode fingers 44 are preferably positioned
as follows: Pos ~ ;ends 63 of steel cathode finger reinforcing means
45 are positioned adjacent to steel sidewall 55 of steel cathode walled
enclosure 13 by means of steel support members 64, 65, 66 and 67.
Support members 64 and 65 are attached in any suitable manner, as by
welding, to cathode finger reinforcing means 45 and rest upon support
members 66 and 67 which are attached in any suitable manner, as by welding,
to sidewall 55. Support members 64 and 65 can be attached or fastened
to support members 66 and 67, respectively, however, it is preferred that
19 _
10536(~7
support members 64 and 65 not be attached or fastened so that both
linear and horizontal thermal expansion and/or contraction can be
provided for cathode fingers 44.
Perforated steel plates 47 are attached in any suitable manner,
as by welding, to sidewalls 17, 54, 55 and 56, respectively, and to
adjacent perforated steel plates 46 thereby forming peripheral chamber 48.
Copper rods 62 are preferably of different lengths and are
preferably positioned on cathode finger reinforcing means 45 as shown in
FIGURE 5. Steel tips 61 are attached in any suitable manner, as by
welding, to ends 68 of copper rods 62 and steel plate 53 is attached in
any suitable manner,as by welding, to linear ends 73 of copper rods 62
thereby forming cathode copper assembly 69. Cathode copper assembly 69
is attached to cathode finger reinforcing means 45 in any suitable manner,
as by welding steel tips 61 and steel plate 53 to steel cathode finger
reinforcing means 45. Copper rods 62 can thus be positioned on cathode
finger reinforcing means 45. Copper rods 62 are of sufficient length and
preferably are of different lengths to maintain substantially uniform
current density through cathode finger 44. Copper rods 62 do not
necessarily have to be round or uniform in cross-section and can be square,
rectangular, hexagonal, octagonal or the like in cross-section and can
vary in cross-section along their lengths. It is important, however,
that copper rods 62 be of sufficient length and cross-section to carry
an electric current and to maintain a substantially uniform current
density through cathode fingers 44 without any significant voltage drop
across cathode fingers 44 and with the most economical power consumption
in cathode fingers 44.
The use of a suitable highly conductive metal, such as copper,
in cathode fingers 44 as shown in FIGURES 4, 5, 6, 7 and 8 is considered
to be a novel use of a suitable highly conductive metal in the cathode
fingers. The use of copper in the cathode fingers is disclosed in U.S.
- 20 -
. .
.. . . . .. .
.
'- ~, ' ' ' ' ' ' ~ ' ',
lOS36(~7 "
Patents 3,464,912 by Emery et al. issued Sept. 2, 1969 to Hooker and
3,493,487 by Ruthel et al. issued Feb. 3, 1970 to Hooker, however,
these disclosed uses of copper in the cathode fingers do not disclose,
much less teach, the use of copper in the cathode fingers of an electro-
lytic cell in the manner as taught herein.
qhepreferred method of positioning copper rods 62 on cathode
finger reinforcing means 45 and in cathode fingers 44 is also novel.
Steel tips 61 are welded to ends 68 of copper rods 62 and steel plate
53 is welded to linear ends 73 of copper rods 62 thereby forming cathode
copper assembly 69. Any warpage from the welding of steel tips 61 and
steel plate 53 to copper ends 62 is corrected or compensated for before
cathode copper assembly 69 is attached to cathode finger reinforcing
means 45. Cathode copper assembly 69 is attached to cathode finger
reinforcing means 45 by welding steel tips 61 and steel plate 53 to
steel cathode finger reinforcing means 45. Copper rods 62 are thus
positioned on cathode finger reinforcing means 45 and in cathode fingers
44. In this manner, all the copper to steel welds are made prior to the
welding of cathode copper assembly 69 to cathode finger reinforcing
means 45 and any metal warpage from welding is substantially eliminated.
The novel cathode fingers enable the electrolytic cell of the
present invention to be designed to operate as a chlor-alkali diaphragm
cell at high current capacities of about 150,000 amperes and upward to
about 200,000 amperes while maintaining high operating efficiencies.
These high current capacities provide for high production capacities
which result in high production rates for given cell room floor areas
and reduce capital investment and operating costs. In addition to being
capable of operation at high amperages, the electrolytic cell of the
present invention can also efficiently operate at lower amperages, such
as about 55,000 amperes using the novel cathode fingers.
- 21 -
1053bO7
Referring now to FIGURE 6, the opposite side of cathode
finger reinforcing means 45 shown in FIGURE 5 is shown and the visible
configuration of copper rods 62 positioned thereon is also shown. Cathode
copper assembly 69 which comprises copper rods 62, steel plate 53 and
steel tips 61 is shown positioned on cathode fingers reinforcing means
45. Cathode fingers reinforcing means 45 can be provided with protrusions
59 and perforated steel plates 46 can be attached in any suitable manner,
as by welding, to protrusions 59 thereby providing additional compartment
space for hydrogen gas, formed at the cathode during electrolysis, to be
channeled to peripheral chamber 48. Protrusions 59 are positioned at
spaced intervals on cathode finger reinforcing means 45 and only a
representative portion are shown in this figure.
Referring now to FIGURES 7 & 8, another embodiment of a cathode
finger reinforcing means is shown and a configuration of copper rods
positioned thereon is also shown. In this embodiment, cathode finger
reinforcing means 111 comprises steel plate 112 having steel peg or pin
means 113 extending therefrom. Cathode copper assembly 69 which comprises
copper rods 62, steel plate 53 and steel tips 61 is shown positioned on
steel plate 112 of cathode finger reinforcing means 111 with a portion
of steel plate 112 removed to accommodate steel plate 53. Cathode copper
assembly 69 is attached to cathode finger reinforcing means 111 in any
suitable manner, as by welding steel plate 53 and steel tips 61 to steel
plate 112. Perforated steel plates 46 can be attached in any suitable
manner, as by welding, to steel peg means 113 thereby providing compart-
ment space for hydrogen gas, formed at the cathode during electrolysis,
to be channeled to peripheral chamber 48.
Referring now to FIGURES 9 and 10, anode base structure 74
comprises copper plate 75 and copper plate 76 and can also comprise steel
plates 77, 78, 79, 81 and 98 or any other suitable structural means.
- 22 -
lOS3~ 7
Copper plates 75 and 76 and steel plates 77, 78, 79 and 81 and 98 are
connected in any suitable manner, as by bolting or welding, to provide
a unitary structure having suitable structural support means. Anode base
structure 74 can be protected from corrosion by elastomeric sealing pad
49. Copper plates 75 and 76 can be provided with anode blade attachment
means 82 which can be used to attach anode blades 72 to copper plates
75 and 76.
Anode blades 72 can be fabricated from any suitable electri-
cally conductive material which will resist the corrosive attack of the
various cel1 reactants and products with which they may come in contact.
Anode blades 72 are preferably metallic anode blades. Typically, anode
blades 72 can be fabricated from a so-called valve metal, such as titanium,
tantalum or niobium as well as alloys of these in which the valve metal
constitutes at least about 90% of the alloy. The surface of the valve
metal may be made active by means of a coating of one or more noble metals,
noble metal oxides, or mixtures of such oxides, either alone or with oxides
of the valve metal. The noble metals which may be used include ruthenium,
rhodium, palladium, irridium, and platinum. Particularly preferred metal
anodes are those formed of ti~tanium and having a mixed titanium oxide
and ruthenium oxide coating on the surface, as is described in U.S. Patent
3,632,498. Additionally, the valve metal substrate may be clad on a more
electrically conductive metal core, such as aluminum, steel, copper, or
the like.
Anode blades 72 can be attached to copper plates 75 and 76 in
any suitable manner as by means of nuts and/or bolts, secured projections,
studs, welding or the like. A typical method of attaching anode blades
72 to copper plates 75 and 76 can be found in U.S. Patent 3,591,483.
Anode busbar 97 can be provided by attaching steel contact
plates 89 and 91 using means 85 to copper plate 75 and providing the said
steel and copper plates with holes 83 which can serve as means for attaching
- 23 -
~05360'7
intercell connectors carrying electricity from an adjacent cell or leads
carrying electricity from another source to anode busbar 97.
FIGURE 10 shows that the configuration of the cross-sections of
copper plates 75 and 76 form the cross-sectional shape of a substantially
stair-stepped truncated right triangle. Copper plates 75 and 76 have
different relative dimensions and are positioned in such a configuration
wherein copper plates 75 and 76 are adapted to carry an electric current
and to maintain a substantially uniform current density through anode base
structure 74 to electrical contact points adjacent to anode blades 72
without any significant voltage drop across anode base structure 74 and
with the most economical power consumption in anode base structure 74.
Substantially uniform current density is achieved by the configuration of
the different cross-sections of copper plates 75 and 76 which form the
cross-sectional shape of a substantially stair-stepped truncated right
triangle where electric current is removed from the copper plates in a
substantially uniform manner as the cross-section of the copper plates
is decreased.
In a typical circuit of electrolytic cell, electric current is :
carried through intercell connectors (not shown) to anode busbar 97 of
anode base structure 74. Electric current is then carried and a sub-
stantially uniform current density is maintained through anode base
structure 74 without any significant voltage drop across anode base
structure 74 and with the most economical power consumption in anode
base structure 74. Electric current is carried and a substantially
uniform current density is maintained through anode base structure 74
by means of the configuration and the different relative dimensions of
copper plates 75 and 76. Electric current is thus carried through anode
base structure 74 to electric contact points where it is distributed to
anode blades 72 and, under these conditions, the electric current is
readily carried to all sections of anode blades 72.
- 24
10536~37
The novel anode base structure makes the most economic use of
invested capital, namely, the amount of copper or other suitable highly
conductive metal used in the anode base structure. The configuration
and different relat;ve dimensions of the copper plates significantly
reduce the amount of copper or other suitable highly conductive metal
required in the anode base structure as compared to the prior art. The
copper plates by means of their configuration and different relative
dimensions are also adapted to carry an electric current and to maintain
a substantially uniform current density through the anode base structure.
The configuration and dimensions of the copper plates can vary
depending on the designed current capacity of the electrolytic cell and
also can vary depending on a number of factors such as the current den-
sity, the conductivity of the metal used, the amount of weld area, the
fabrication costs and the like.
The novel anode base structure provides improved electrical
conductivity to the anode blades thereby providing a minimum or no
significant voltage drop across the anode base structure with a sub-
stantial reduction in copper or other suitable highly conductive metal
expenditures as compared to the prior art.
The novel anode base structure enables the electrolytic cell
of the present invention to be designed to operate as a chlor-alkali
diaphragm cell at high current capacities of about 150,000 amperes and
upward to about 200,000 amperes while maintaining high operating effi-
ciencies. These high current capacities provide for high production
capacities which result in high production rates for given cell room
floor areas and reduce capital investment and operating costs. In
addition to being capable of operation at high amperages, the electro-
lytic cell of the present invention can also efficiently operate at lower
amperages, such as about 55,000 amperes using the novel anode base
structure.
- 25 -
'
1053607
Anode base structure 74 can be provided with cooling means 92.
The coolant, preferably water, is circulated through cooling means 92 by
entry through entrance port 93 and by passage through coolant conveying
means 95. After entry through entrance port 93, the coolant is passed
along steel plate 87 into and through cooling device 96 and then again
along steel plate 87. The coolant is then passed along steel plate 88
and then along and around steel plate 89. The coolant is then passed
along the opposite side of steel plate 89 and then along the opposite
side of steel plate 88. The coolant is then passed along the opposite
side of steel plate 87 and is discharged through exit port 94. Coolant
conveying means 95 can be any suitable coolant conveying means such as
copper tubing connecting cooling device 96 and coolant conveying channels
positioned along the sides and ends of steel contact plates 87, 88 and
89. Cooling means 92 as shown in this figure and described herein is
merely a typical cooling means and cooling means 92 should not be limited
to the design as shown in this figure and described herein.
The use of cooling system 92 permits considerably less copper
to be used in anode base structure 74 which results in a substantial -
reduction in capital investment costs for anode copper. While cooling
system 92 is provided primarily for use when an adjacent electrolytic
cell is jumpered, cooling system 92 can be used during routine cell
operation either to cool anode copper during any periodic electric
current overloads or to continuously cool anode copper, thereby permitting
further reductions in the use of copper in anode base structure 74 with
an accompanying reduction in capital costs for anode copper.
Anode jumper busbar 99 can be provided by attaching steel contact
plates 87 and 88 using means 86 to copper plate 75 and providing the
steel and copper plates with holes 84 which can serve as means for
attaching anode jumper connectors when an adjacent electrolytic cell is
- 26 -
. ' : . . ' .
105360~7
jumpered and is removed from the electrical circuit. It is during
this jumpering operation that cooling system 92 can provide its greatest
utility by preventing the temperatures in anode base structure 74 from
rising to levels whereby damage to anode base structure 74 or other
components of electrolytic cell 11 occurs.
Referring now to FIGURE 11, anode base structure 74 is shown
in another embodiment wherein anode base structure 74 is provided with
structural support means 52 which can supply additional structural support
for anode base structure 74. This embodiment would be advantageous and
preferably where anode base structure 74 is fabricated from a highly
conductive metal, such as copper, which has excellent electrical pro-
perties but has relatively poor structural properties. Structural support
means 52 can be fabricated from any number of suitable structural materials
such as aluminum, iron, steel and the like and alloys thereof such as
stainless steel and other chromium steels, nickel steels and the like
which have sufficient strength to provide the needed support. Such
structural materials can have the shapes of I beams, T beams, L beams,
U beams and the like. Structural support means 52 does not have to be
fabricated from a metal and can be fabricated from other suitable struc-
tural materials such as concrete, reinforced concrete or the like.
Referring now to FIGURES 12, 13 and 14, another embodiment of
anode base structure 74, shown in FIGURES 9, 10 and 11, is shown in
FIGURES 12, 13 and 14. The description of FIGURES 9, 10 and 11 applies
to FIGURES 12, 13 and 14. The difference in FIGURES 12, 13 and 14 from
FIGURES 9, 10 and 11 is the addition of copper plates 101 and 102 and
steel plates 103 and 104. There is also the addition of a fourth row of
anode blades 72 and a slight modification in cooling means 92 and jumper
busbar 99.
FIGURES 13 and 14 show that the configuration of the cross-
sections of copper plates 75, 76, 101 and 102 form the cross-sectional
- 27 -
1053~;07
shape of a substantially stair-stepped truncated right triangle. Copper
plates 75, 76, 101 and 102 have different relative dimensions and are
positioned in such a configuration wherein copper plates 75, 76, 101 and
102 are adapted to carry an electric current and to maintain a sub-
stantially uniform current density through anode base structure 74 toelectrical contact points adjacent to anode blades 72 without any signi-
ficant voltage drop across anode base structure 74 and with the most
economical power consumption in anode base structure 74,
Substantially uniform current density is achieved by the con-
figuration of the different cross-sections of copper plates 75, 76, 101
and 102 which form the cross-sectional shape of a substantially stair-
stepped truncated right triangle where electric current is removed from
the copper plates in a substantially uniform manner as the cross-section
of the copper plates is decreased.
In a typical circuit of electrolytic cells, electric current is
carried through intercell connectors (not shown) to anode busbar 97 of
anode base structure 74. Electric current is then carried and a sub-
stantially uniform current density is maintained through anode base
structure 74 without any significant voltage drop across anode base
structure 74 and with the most economical power consumption in anode base
structure 74. Electric current is carried and a substantially uniform
current density is maintained through anode base structure 74 by means
of the configuration and the different relative dimensions of copper
plates 75, 76, 101 and 102. Electric current is thus carried through
anode base structure 74 to electrical contact points where it is dis-
tributed to anode blades 72, and, under these conditions, the electric
current is readily carried to all sections of anode blades 72.
The novel anode base structure makes the most economical use
of invested capital, namely, the amount of copper or other suitable highly
~ - 28 -
1053607
conductive metal used in the anode base structure. The configurationand different relative dimensions of the copper plates significantly
reduce the amount of copper or other suitable highly conductive metal
required in the anode base structure as compared to the prior art. The
copper plates by means of their configuration and different relative
dimensions are also adapted to carry an electric current and to maintain
a substantially uniform current density through the anode base structure.
The configuration and dimensions of the copper plates can vary
depending on the designed current capacity of the electrolytic cell and
also can vary depending on a number of factors such as the current density,
the conductivity of the metal used, the amount of weld area, the fabri-
cation costs and the like.
The novel anode base structure provided improved electrical
conductivity to the anode blades thereby providing a minimum or no
significant voltage drop across the anode base structure with a sub-
stantial reduction in copper or other suitable highly conductive metal
expenditures as compared to the prior art.
Anode base structure 74 shown in FIGURES 9-14 can be an
embodiment of conductive anode base 51 shown in FIGURES 2 and 4.
The novel anode base structure enables the electrolytic cell
of the present invention to be designed to operate as a chlor-alkali-
diaphragm cell at high current capacities of about 150,000 amperes and
upward to about 200,000 amperes while maintaining high operating effi-
ciencies. These high current capacities provide for high production
capacities which result in high production rates for given cell room
floor areas and reduce capital investment and operating costs. In
addition to being capable of operation at high amperages, the electro-
lytic cell of the present invention can also efficiently operate at
lower amperages, such as about 55,000 amperes using the novel anode base
structure.
- 28a -
10536Q7
PREFERRED EMBODIM_NTS
The following Example illustrates the practice of the present
invention and a mode of utilizing the present invention.
EXAMPLE
The following data is typical of the performance of the novel
electrolytic cell of the present invention operating at a current capacity
of 150,000 amperes. The performance is compared with the performance
of a smaller electrolytic cell of the prior art, also equipped with
metal anode blades, operating at a current capacity of 84,000 amperes.
Both electrolytic cells are chlor-alkali diaphragm cells.
84,000 Ampere Cell 150,000 Ampere Cell
of the Prior Art of the Present Invention
Current Efficiency 96.4 96.4
Average Cell Voltage
(including busbars~ 3.84 3.83
Power - KWHDC/Ton C12 2735 2725
Cell Liquor Temperature - C. 100.5 100.7
Anolyte Temperature - C. 94.5 94.7
Percent NaOH in Cell Liquor 11.5* 11.5*
Chlorine Production - Tons/Day 2.83 5.06
NaOH Production - Tons/Day3.20 5.71
Brlne Feed - Grams/Liter 325 325
Current Density - Amperes/Sq. In. 1.5 1.5
* The cells can be operated at lower caustic content in the cell
liquor. This will result in greater current efficiencies.
The above data show that the novel electrolytic cell of the
present invention operates at essentially the same current efficiency,
voltage and operating conditions as the smaller electrolytic cell of
the prior art at the same anode current density. The novel electro-
lytic cell of the present invention has a higher production rate for a
given cell room floor area, uses less operating labor and also has a
lower capital investment per ton of chlorine produced.
~ ~ 29
. . .
- . , . . : :
, ,` , ., . . : ` :
~053~0~
This example shows that an electrolytic cell can be designed
to operate at a high current capacity to provide a high production
capacity and a high production rate while maintaining high operating
efficiencies.
The novel electrolytic cell of the present invention can have
many other uses. For example, alkali metal chlorates can be produced
using the electrolytic cell of the present invention by further reacting
the formed caustic and chlorine outside of the cell. In this instance,
solutions containing both alkali metal chlorate and alkali metal chloride
can be recirculated to the electrolytic cell for further electrolysis.
The electrolytic cell can be utilized for the electrolysis of hydro-
chloric acid by electrolyzing hydrochloric acid alone or in combination
with an alkali metal chloride. Thus, the novel electrolytic cell of
the present invention is highly useful in these and many other aqueous
processes.
While there have been described various embodiments of the
present invention, the apparatus described is not intended to be
understood as limiting the scope of the present invention. It is
realized that changes therein are possible. It is further intended
that each component recited in any of the following claims is to be
understood as referring to all equivalent components for accomplishing
the same results in substantially the same or an equivalent manner.
The following claims are intended to cover the present invention
broadly in whatever form the principals thereof may be utilized.
_29a
