EP0419052A1 - Electrolytic generation of chlorine - Google Patents
Electrolytic generation of chlorine Download PDFInfo
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- EP0419052A1 EP0419052A1 EP90309226A EP90309226A EP0419052A1 EP 0419052 A1 EP0419052 A1 EP 0419052A1 EP 90309226 A EP90309226 A EP 90309226A EP 90309226 A EP90309226 A EP 90309226A EP 0419052 A1 EP0419052 A1 EP 0419052A1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B15/00—Operating or servicing cells
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
Definitions
- This invention relates to the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution by electrolysis of a saturated sodium chloride solution in an electrolytic cell.
- apparatus for carrying out this process comprises an electrolytic cell having an anodic compartment containing an anode and a cathodic compartment containing a cathode, the two being separated by an ion permeable membrane.
- the anode is comprised of impervious graphite and the cathode is an austenitic stainless steel.
- the anodic compartment contains a sodium chloride solution which is dissociated into sodium ions (Na+) and chloride ions (Cl ⁇ ).
- Electrolysis of this solution causes oxidation of the chloride ions to chlorine gas (Cl2) and a movement of sodium ions through the ion permeable membrane to the cathodic compartment.
- water dissociates giving hydronium ions (H2O ⁇ ) and hydroxyl ions (OH ⁇ ).
- the electrolysis results in a reduction of the hydronium ions to hydrogen gas (H2).
- the sodium ions which pass through the ion permeable membrane combine with the hydroxyl ions to give sodium hydroxide (NaOH), also known as caustic soda.
- the sodium ions moving across the membrane cause a nett movement of water across the membrane as water of hydration resulting in a nett increase in volume of the catholyte and a nett decrease in volume of the anolyte.
- the chlorine gas generated may be used for example for the chlorination of water.
- the sodium hydroxide formed may be utilized to form sodium hypochlorite (NaOCl) or may be disposed of by some other means.
- apparatus for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution which comprises: an electrolytic cell having an anodic compartment containing an anode and having an inlet at a low point for the sodium or potassium chloride solution and an outlet at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment containing a cathode and having an inlet at a low point and an outlet at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane separating the anodic compartment and the cathodic compartment; a first container for the sodium or potassium chloride solution having an outlet connected to the inlet of the anodic compartment and an inlet connected to the outlet of the anodic compartment; a second container for the sodium or potassium hydroxide solution having an outlet connected to the inlet of the cathodic compartment and an inlet connected to the outlet of the cath
- liquid levels in the first container and the second containers are maintained above the liquid levels in the electrolytic cell.
- the apparatus includes valves located between the inlet of the anodic compartment and the outlet of the first container and the outlet of the anodic compartment and the inlet of the first container and the inlet of the cathodic compartment and the outlet of the second container and the outlet of the cathodic compartment and the inlet of the second container, so that the electrolytic cell may be isolated from the first and second containers.
- the first container includes an inlet for sodium or potassium chloride and an outlet for the chlorine gas, and optionally also level indicator for the sodium or potassium chloride solution.
- the second container preferably includes an outlet for the sodium or potassium hydroxide solution and an outlet for the hydrogen gas.
- the anode is formed of titanium coated with a noble metal oxide and the cathode is formed of an austenitic stainless steel or formed of titanium.
- the anode and the cathode may be connected to a conventional power supply.
- an electrolytic cell for use in the apparatus described above.
- a container for a sodium or potassium chloride solution for use in the apparatus described above.
- a container for a saturated sodium or potassium hydroxide solution for use in the apparatus described above.
- a method of generating chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution in apparatus comprising an electrolytic cell having an anodic compartment containing an anode and having an inlet at a low point for the sodium or potassium chloride solution and an outlet at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment containing a cathode and having an inlet at a low point and an outlet at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane separating the anodic compartment and the cathodic compartment, a first container for the sodium or potassium chloride solution having an outlet connected to the inlet of the anodic compartment and an inlet connected to the outlet of the anodic compartment, and a second container for the sodium or potassium hydroxide solution having an outlet connected to the inlet of the cathodic compartment and an inlet
- apparatus 10 for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution by electrolysis of a saturated sodium chloride solution consists of an electrolytic cell 12 connected to a first container 14 for the sodium chloride solution and a second container 16 for the sodium hydroxide solution.
- the electrolytic cell 12 comprises a cathodic compartment 18 and an anodic compartment 20.
- the cathodic compartment 18 has a top side 22 which slopes upwardly towards an outlet 24 for the sodium hydroxide solution.
- the top side 22 of the cathodic compartment 18 is formed with a V-formation 26 in the vicinity of the sodium hydroxide outlet 24.
- the opposite or bottom side 28 of the cathodic compartment 18 includes an inlet 30.
- the cathodic compartment 18 also includes two flanges 32 to which is bolted a cathode 34. Referring to Figure 3, it can be seen that the cathode 34 includes a series of holes 36 drilled into it to facilitate movement of sodium hydroxide solution therethrough. Two bolts 38 run from the cathode 34 to the outside of the cathodic compartment 18 for electrical connection of the cathode 34 to an external source of power.
- the anodic compartment 20 includes an outlet 40 for depleted sodium chloride solution and an inlet 42 for the saturated sodium chloride solution.
- the top side of the anodic compartment 20 in the vicinity of the outlet 42 is V-shaped as illustrated at 44 in Figure 4, to facilitate collection of the chlorine gas.
- the anodic compartment 20 also includes an anode 46 bolted to the anodic compartment 20 by bolts 48 to facilitate electrical connection of the anode 46 to an external source of power.
- the anodic compartment 20 and the cathodic compartment 18 are bolted together through external flanges 48 and sandwiched therebetween is an ion permeable membrane 50.
- the body of the cathodic compartment 18 and the body of the anodic compartment 20 and the flanges 32 and 48 are all preferably comprised of a suitable plastics material such as polyvinylchloride.
- the cathode 34 preferably comprises an austenitic stainless steel.
- the bolts 38 preferably comprise a stainless steel.
- the anode 46 preferably comprise a high grade titanium coated with a noble metal oxide such as platinum or ruthenium.
- the bolts 48 are preferably comprised of titanium.
- the ion permeable membrane 50 may be any suitable ion permeable membrane.
- the first container 14 for the sodium chloride solution includes an outlet 52 for the sodium chloride solution connected via a pipe 54 and a valve 56 to the inlet 42 into the anodic compartment 20.
- the first container 14 also includes an inlet 58 for the depleted sodium chloride solution which is connected via a pipe 60 and a valve 62 to the outlet 40 from the anodic compartment 20.
- the first container 14 also includes an inlet 64 for sodium chloride and a level metering stick 60 for metering the level of the sodium chloride solution in the container 14.
- the container 14 also includes an outlet 68 for the chlorine gas.
- the second container 16 for the sodium hydroxide solution includes an outlet 70 for the sodium hydroxide solution connected via a pipe 72 and a valve 74 to the inlet 30 into the cathodic compartment 18.
- the second container 16 also includes an inlet 76 for the sodium hydroxide solution connected via a pipe 78 and a valve 80 to the outlet 24 from the cathodic compartment 18.
- the second container 16 may also include an outlet 82 for drainage of the sodium hydroxide solution.
- the containers 14 and 16 may be made of any suitable material.
- the apparatus 10 may also include a fresh water inlet at a suitable site to flush out any build-up of calcium and magnesium between the anode 46 and the membrane 50.
- a saturated sodium chloride solution is added to the first container 14 and to the anodic compartment 20.
- the second container 16 and the cathodic compartment 18 may either be filled with water or preferably, with a dilute sodium hydroxide solution to facilitate start-up.
- the valves 56, 62, 74 and 80 are all open and the anode 46 and the cathode 34 are connected to the external power source.
- the sodium chloride solution dissociates into sodium ions and chloride ions. Electrolysis of this solution causes oxidation of the chloride ions to chlorine gas and a movement of sodium ions through the membrane 50 into the cathodic compartment 18.
- the cathodic compartment 18 water dissociates giving hydronium ions and hydroxyl ions and the electrolysis results in a reduction of the hydronium ions to hydrogen gas.
- the sodium ions having passed through the membrane 50 combine with the hydroxyl ions to yield sodium hydroxide.
- the chlorine gas generated in the anodic compartment 20 rises to the top of the compartment 20 and exits through the outlet 40, carrying with it depleted sodium chloride solution.
- This solution flows through the pipe 60 and the inlet 58 into the first container 14.
- fresh saturated sodium chloride solution flows out of the outlet 52 of the first container 14 through the pipe 54 and into the inlet 42 into the anodic compartment 20.
- the rate of chlorine gas generation determines the rate of flow from the anodic compartment 20 to the first container 14 and from the first container 14 back to the anodic compartment 20.
- the hydrogen gas generated in the cathodic compartment 18 rises to the top of the cathodic compartment 18 and exits the cathodic compartment 18 through the outlet 24, carrying with it sodium hydroxide solution.
- Solution flows through the pipe 78 into the inlet 76 and then into the second container 16 where it accumulates.
- sodium hydroxide solution (or initially water) flows out of the outlet 70 in the second container 16 through the pipe 72 and into the inlet 30 into the cathodic compartment 18.
- the rate of generation of hydrogen gas in the cathodic compartment 18 determines the rate of flow of fluids between the cathodic compartment 18 and the second container 16 and from the second container 16 back to the cathodic compartment 18.
- the apparatus 10 may include suitable means for venting any excess hydrogen gas.
- the first and second containers 14, 16 may be connected to the electrolytic cell 12 and the valve 56, 62, 74 and 80 may be reopened so that the process may be recommended.
- the apparatus 10 may be used with potassium chloride instead of sodium chloride, in which case potassium hydroxide is generated.
- the apparatus 10 illustrated in Figure 1 may be used as is, i.e. with a single electrolytic cell 12 and single tanks 14, 16.
- a series of electrolytic cells may be arranged in series to increase the output of chlorine gas from the apparatus.
- the apparatus may be designed to provide anything between 100 g and 1000 kg of chlorine gas per day.
- the two main features of the apparatus of the invention are firstly that the electrolytic cell is isolated from the sodium chloride solution storage container and the sodium hydroxide solution storage container which facilitates the disposal of the sodium hydroxide solution and maintenance of the electrolytic cell, and secondly that the circulation of liquids between the electrolytic cell and the two storage containers is caused by the generation of chlorine gas and hydrogen gas in the anodic and cathodic compartments respectively, thus obviating the need for an external pump or pumps.
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Abstract
Apparatus 10 for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution by electrolysis of a sodium chloride solution comprises an electrolytic cell 12 having an anodic compartment 30 containing an anode and having an inlet 42 for the sodium chloride solution and an outlet 40 for the depleted sodium chloride solution, a cathodic compartment 18 containing a cathode and having an inlet 30 and an outlet 24 for the sodium hydroxide solution, and an ion permeable membrane 50 separating the anodic compartment 20 and the cathodic compartment 18, a first container 14 for the sodium chloride solution having an outlet 52 connected to the inlet 42 of the anodic compartment 20 and an inlet 58 connected to the outlet 40 of the anodic compartment 20, and a second container 16 for the sodium hydroxide solution having an outlet 70 connected to the inlet 30 of the cathodic compartment 18 and an inlet 76 connected to the outlet 24 of the cathodic compartment 18. Circulation of the liquids between the anodic compartment 20 and the first container 14 and between the cathodic compartment 18 and the second container 16 is caused solely by the generation of the chlorine gas and the hydrogen gas respectively.
Description
- This invention relates to the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution by electrolysis of a saturated sodium chloride solution in an electrolytic cell.
- It is well known to generate chlorine gas, hydrogen gas and sodium hydroxide in an electrolytic cell by the electrolysis of a sodium chloride solution, the chlorine being used for example for chlorinating water. Generally, apparatus for carrying out this process comprises an electrolytic cell having an anodic compartment containing an anode and a cathodic compartment containing a cathode, the two being separated by an ion permeable membrane. Generally, the anode is comprised of impervious graphite and the cathode is an austenitic stainless steel. The anodic compartment contains a sodium chloride solution which is dissociated into sodium ions (Na⁺) and chloride ions (Cl⁻).
- Electrolysis of this solution causes oxidation of the chloride ions to chlorine gas (Cl₂) and a movement of sodium ions through the ion permeable membrane to the cathodic compartment. In the cathodic compartment, water dissociates giving hydronium ions (H₂O⁻) and hydroxyl ions (OH⁻). The electrolysis results in a reduction of the hydronium ions to hydrogen gas (H₂). The sodium ions which pass through the ion permeable membrane combine with the hydroxyl ions to give sodium hydroxide (NaOH), also known as caustic soda. The sodium ions moving across the membrane cause a nett movement of water across the membrane as water of hydration resulting in a nett increase in volume of the catholyte and a nett decrease in volume of the anolyte. As stated above, the chlorine gas generated may be used for example for the chlorination of water. The sodium hydroxide formed may be utilized to form sodium hypochlorite (NaOCl) or may be disposed of by some other means.
- This process, carried out as described above wholly within an electrolytic cell, has several disadvantages. Firstly, there are problems of safety when the cell must be drained of the sodium hydroxide, as this is very caustic. Secondly, maintenance of the cell is difficult in that both the anodic compartment and the cathodic compartment must be drained before such maintenance can be carried out.
- It is known to operate the process with an electrolytic cell with external containers for the sodium chloride solution and the sodium hydroxide solution. However, in this case, pumps are required to pump the various solutions between the two external tanks and the anodic and cathodic compartments of the electrolytic cell. This obviously increases the complexity and cost of the process.
- There is a need for a new apparatus for the generation of chlorine gas from a sodium chloride solution which overcomes the above disadvantages.
- According to the invention there is provided apparatus for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution which comprises:
an electrolytic cell having an anodic compartment containing an anode and having an inlet at a low point for the sodium or potassium chloride solution and an outlet at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment containing a cathode and having an inlet at a low point and an outlet at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane separating the anodic compartment and the cathodic compartment;
a first container for the sodium or potassium chloride solution having an outlet connected to the inlet of the anodic compartment and an inlet connected to the outlet of the anodic compartment;
a second container for the sodium or potassium hydroxide solution having an outlet connected to the inlet of the cathodic compartment and an inlet connected to the outlet of the cathodic compartment;
in use the circulation of the liquids between the anodic compartment and the first container and between the cathodic compartment and the second container being caused by the generation of the chlorine gas and the hydrogen gas respectively. - Preferably the liquid levels in the first container and the second containers are maintained above the liquid levels in the electrolytic cell.
- Preferably, the apparatus includes valves located between the inlet of the anodic compartment and the outlet of the first container and the outlet of the anodic compartment and the inlet of the first container and the inlet of the cathodic compartment and the outlet of the second container and the outlet of the cathodic compartment and the inlet of the second container, so that the electrolytic cell may be isolated from the first and second containers.
- Preferably, the first container includes an inlet for sodium or potassium chloride and an outlet for the chlorine gas, and optionally also level indicator for the sodium or potassium chloride solution. Likewise, the second container preferably includes an outlet for the sodium or potassium hydroxide solution and an outlet for the hydrogen gas.
- Preferably, the anode is formed of titanium coated with a noble metal oxide and the cathode is formed of an austenitic stainless steel or formed of titanium.
- The anode and the cathode may be connected to a conventional power supply.
- According to a second aspect of the invention there is provided an electrolytic cell for use in the apparatus described above.
- According to a third aspect of the invention, there is provided a container for a sodium or potassium chloride solution for use in the apparatus described above.
- According to a fourth aspect of the invention there is provided a container for a saturated sodium or potassium hydroxide solution for use in the apparatus described above.
- According to a fifth aspect of the invention there is provided a method of generating chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution in apparatus comprising an electrolytic cell having an anodic compartment containing an anode and having an inlet at a low point for the sodium or potassium chloride solution and an outlet at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment containing a cathode and having an inlet at a low point and an outlet at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane separating the anodic compartment and the cathodic compartment, a first container for the sodium or potassium chloride solution having an outlet connected to the inlet of the anodic compartment and an inlet connected to the outlet of the anodic compartment, and a second container for the sodium or potassium hydroxide solution having an outlet connected to the inlet of the cathodic compartment and an inlet connected to the outlet of the cathodic compartment, including the steps of:
- (a) providing in the anodic compartment a sodium chloride solution or a potassium chloride solution and providing in the cathodic compartment water or a sodium hydroxide solution or a potassium hydroxide solution;
- (b) electrolysing the solutions to generate chlorine gas in the anodic compartment and a movement of sodium or potassium ions through the ion permeable membrane into the cathodic compartment, and to generate hydrogen gas and sodium hydroxide or potassium hydroxide in the cathodic compartment; and
- (c) causing a circulation of the sodium chloride solution or potassium chloride solution between the anodic compartment and the first container by the generation of the chlorine gas in the anodic compartment and causing a circulation of the sodium hydroxide solution or potassium hydroxide solution between the cathodic compartment and the second container by the generation of the hydrogen gas in the cathodic compartment.
- The invention will now be described in more detail with reference to the accompanying drawings where:
- Figure 1 is a schematic view of apparatus according to the invention;
- Figure 2 is a sectional side view of an electrolytic cell for use in the apparatus of Figure 1;
- Figure 3 is a sectional top view of a cathode for use in the apparatus of Figure 1; and
- Figure 4 is a sectional top view of an anode for use in the apparatus in Figure 1.
- Referring to the drawings, apparatus 10 for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution by electrolysis of a saturated sodium chloride solution consists of an
electrolytic cell 12 connected to afirst container 14 for the sodium chloride solution and asecond container 16 for the sodium hydroxide solution. - The
electrolytic cell 12 comprises acathodic compartment 18 and ananodic compartment 20. Thecathodic compartment 18 has a top side 22 which slopes upwardly towards anoutlet 24 for the sodium hydroxide solution. The top side 22 of thecathodic compartment 18 is formed with a V-formation 26 in the vicinity of thesodium hydroxide outlet 24. The opposite orbottom side 28 of thecathodic compartment 18 includes aninlet 30. Thecathodic compartment 18 also includes twoflanges 32 to which is bolted acathode 34. Referring to Figure 3, it can be seen that thecathode 34 includes a series ofholes 36 drilled into it to facilitate movement of sodium hydroxide solution therethrough. Twobolts 38 run from thecathode 34 to the outside of thecathodic compartment 18 for electrical connection of thecathode 34 to an external source of power. - The
anodic compartment 20 includes anoutlet 40 for depleted sodium chloride solution and aninlet 42 for the saturated sodium chloride solution. The top side of theanodic compartment 20 in the vicinity of theoutlet 42 is V-shaped as illustrated at 44 in Figure 4, to facilitate collection of the chlorine gas. Theanodic compartment 20 also includes ananode 46 bolted to theanodic compartment 20 bybolts 48 to facilitate electrical connection of theanode 46 to an external source of power. - The
anodic compartment 20 and thecathodic compartment 18 are bolted together throughexternal flanges 48 and sandwiched therebetween is an ion permeable membrane 50. - The body of the
cathodic compartment 18 and the body of theanodic compartment 20 and theflanges cathode 34 preferably comprises an austenitic stainless steel. Thebolts 38 preferably comprise a stainless steel. Theanode 46 preferably comprise a high grade titanium coated with a noble metal oxide such as platinum or ruthenium. Thebolts 48 are preferably comprised of titanium. The ion permeable membrane 50 may be any suitable ion permeable membrane. - The
first container 14 for the sodium chloride solution includes anoutlet 52 for the sodium chloride solution connected via a pipe 54 and a valve 56 to theinlet 42 into theanodic compartment 20. Thefirst container 14 also includes an inlet 58 for the depleted sodium chloride solution which is connected via apipe 60 and avalve 62 to theoutlet 40 from theanodic compartment 20. Thefirst container 14 also includes aninlet 64 for sodium chloride and alevel metering stick 60 for metering the level of the sodium chloride solution in thecontainer 14. Thecontainer 14 also includes an outlet 68 for the chlorine gas. - The
second container 16 for the sodium hydroxide solution includes anoutlet 70 for the sodium hydroxide solution connected via apipe 72 and avalve 74 to theinlet 30 into thecathodic compartment 18. Thesecond container 16 also includes an inlet 76 for the sodium hydroxide solution connected via apipe 78 and a valve 80 to theoutlet 24 from thecathodic compartment 18. Thesecond container 16 may also include anoutlet 82 for drainage of the sodium hydroxide solution. - The
containers - The apparatus 10 may also include a fresh water inlet at a suitable site to flush out any build-up of calcium and magnesium between the
anode 46 and the membrane 50. - The use of the apparatus 10 will now be described. On initial start-up, a saturated sodium chloride solution is added to the
first container 14 and to theanodic compartment 20. Thesecond container 16 and thecathodic compartment 18 may either be filled with water or preferably, with a dilute sodium hydroxide solution to facilitate start-up. Thevalves anode 46 and thecathode 34 are connected to the external power source. In theanodic compartment 20 the sodium chloride solution dissociates into sodium ions and chloride ions. Electrolysis of this solution causes oxidation of the chloride ions to chlorine gas and a movement of sodium ions through the membrane 50 into thecathodic compartment 18. In thecathodic compartment 18, water dissociates giving hydronium ions and hydroxyl ions and the electrolysis results in a reduction of the hydronium ions to hydrogen gas. The sodium ions having passed through the membrane 50 combine with the hydroxyl ions to yield sodium hydroxide. The chlorine gas generated in theanodic compartment 20 rises to the top of thecompartment 20 and exits through theoutlet 40, carrying with it depleted sodium chloride solution. This solution flows through thepipe 60 and the inlet 58 into thefirst container 14. As a result of this movement, fresh saturated sodium chloride solution flows out of theoutlet 52 of thefirst container 14 through the pipe 54 and into theinlet 42 into theanodic compartment 20. The rate of chlorine gas generation determines the rate of flow from theanodic compartment 20 to thefirst container 14 and from thefirst container 14 back to theanodic compartment 20. - On the other side of the membrane 50, the hydrogen gas generated in the
cathodic compartment 18 rises to the top of thecathodic compartment 18 and exits thecathodic compartment 18 through theoutlet 24, carrying with it sodium hydroxide solution. Solution flows through thepipe 78 into the inlet 76 and then into thesecond container 16 where it accumulates. As a result of this movement, sodium hydroxide solution (or initially water) flows out of theoutlet 70 in thesecond container 16 through thepipe 72 and into theinlet 30 into thecathodic compartment 18. Again, the rate of generation of hydrogen gas in thecathodic compartment 18 determines the rate of flow of fluids between thecathodic compartment 18 and thesecond container 16 and from thesecond container 16 back to thecathodic compartment 18. The apparatus 10 may include suitable means for venting any excess hydrogen gas. - To keep the process going, al that is required is that periodically fresh sodium chloride is added into the
first container 14 through theinlet 64. When thesecond container 16 becomes full or it is desired to carry out maintenance work on theelectrolytic cell 12, the fourvalves electrolytic cell 12 from thefirst container 14 and thesecond container 16. Thesecond container 16 may now be removed and either drained or replaced with a fresh container. Likewise, any maintenance work that is needed to be carried out on theelectrolytic cell 12 can be done. When thesecond container 16 has been drained or replaced, or when the maintenance work on theelectrolytic cell 12 is complete, the first andsecond containers electrolytic cell 12 and thevalve - The apparatus 10 may be used with potassium chloride instead of sodium chloride, in which case potassium hydroxide is generated.
- The apparatus 10 illustrated in Figure 1 may be used as is, i.e. with a single
electrolytic cell 12 andsingle tanks - The two main features of the apparatus of the invention are firstly that the electrolytic cell is isolated from the sodium chloride solution storage container and the sodium hydroxide solution storage container which facilitates the disposal of the sodium hydroxide solution and maintenance of the electrolytic cell, and secondly that the circulation of liquids between the electrolytic cell and the two storage containers is caused by the generation of chlorine gas and hydrogen gas in the anodic and cathodic compartments respectively, thus obviating the need for an external pump or pumps. These two features lead to the advantages that the equipment is simple and thus both inexpensive to construct and inexpensive to maintain. Further, the safety of the equipment is increased.
Claims (16)
1. Apparatus (10) for the generation of chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution comprises:
an electrolytic cell (12) having an anodic compartment (20) containing an anode (46) and having an inlet (42) at a low point for the sodium or potassium chloride solution and an outlet (40) at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment (18) containing a cathode (34) and having an inlet (30) at a low point and an outlet (24) at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane (50) separating the anodic compartment (20) and the cathodic compartment (18);
a first container (14) for the sodium or potassium chloride solution having an outlet (52) connected to the inlet (42) of the anodic compartment (20) and an inlet (58) connected to the outlet (40) of the anodic compartment (20);
a second container (16) for the sodium or potassium hydroxide solution having an outlet (70) connected to the inlet (30) of the cathodic compartment (18) and an inlet (76) connected to the outlet (24) of the cathodic compartment (18);
in use the circulation of the liquids between the anodic compartment (20) and the first container (14) and between the cathodic compartment (18) and the second container (16) being caused by the generation of the chloride gas and the hydrogen gas respectively.
an electrolytic cell (12) having an anodic compartment (20) containing an anode (46) and having an inlet (42) at a low point for the sodium or potassium chloride solution and an outlet (40) at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment (18) containing a cathode (34) and having an inlet (30) at a low point and an outlet (24) at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane (50) separating the anodic compartment (20) and the cathodic compartment (18);
a first container (14) for the sodium or potassium chloride solution having an outlet (52) connected to the inlet (42) of the anodic compartment (20) and an inlet (58) connected to the outlet (40) of the anodic compartment (20);
a second container (16) for the sodium or potassium hydroxide solution having an outlet (70) connected to the inlet (30) of the cathodic compartment (18) and an inlet (76) connected to the outlet (24) of the cathodic compartment (18);
in use the circulation of the liquids between the anodic compartment (20) and the first container (14) and between the cathodic compartment (18) and the second container (16) being caused by the generation of the chloride gas and the hydrogen gas respectively.
2. Apparatus according to claim 1 wherein the liquid levels in the first container (14) and the second container (16) are maintained above the liquid levels in the electrolytic cell (12).
3. Apparatus according to claim 1 or claim 2 which includes a valve (56) located between theinlet (42) of the anodic compartment (20) and the outlet (52) of the first container (14) and a valve (62) located between the outlet (40) of the anodic compartment (20) and the inlet (58) of the first container (14) so that the electrolytic cell (12) may be isolated from the first container (14).
4. Apparatus according to any one of claims 1 to 3 which includes a valve (74) located between the inlet (30) of the cathodic compartment (18) and the outlet (70) of the second container (16) and a valve (80) located between the outlet (24) of the cathodic compartment (18) and theinlet (76) of the second container (16) so that the electrolytic cell (12) may be isolated from the second container (16).
5. Apparatus according to any one of claims 1 to 4 wherein the first container (14) includes an inlet (64) for sodium chloride or potassium chloride and an outlet (68) for chlorine gas.
6. Apparatus according to any one of claims 1 to 5 wherein the first container (14) includes a level indicator (66) for the sodium chloride or potassium chloride solution.
7. Apparatus according to any one of claims 1 to 6 wherein the second container (16) includes an outlet (82) for sodium hydroxide or potassium hydroxide.
8. Apparatus according to any one of claims 1 to 7 wherein the second container (16) includes an outlet for hydrogen gas.
9. Apparatus according to any one of claims 1 to 8 wherein the anode (46) is formed of titanium coated with a noble metal oxide.
10. Apparatus according to any one of claims 1 to 9 wherein the cathode (34) is formed of an austenitic stainless steel or titanium.
11. An electrolytic cell (12) having an anodic compartment (20) for containing an anode (46) and having an inlet (42) at a low point for a sodium chloride or potassium chloride solution, and an outlet (40) at a high point for a depleted sodium chloride or potassium chloride solution, a cathodic compartment (18) for containing a cathode (34) and having an inlet (30) at a low point and an outlet (24) at a high point for a sodium hydroxide or potassium hydroxide solution, and an ion permeable membrane (50) separating the anodic compartment (20) and the cathodic compartment (18) for use in the apparatus (10) of any one of claims 1 to 10.
12. A container (14) for a sodium chloride solution or a potassium chloride solution having an inlet (58) and an outlet (54) for use in the apparatus (10) of any one of claims 1 to 10.
13. A container (16) for a sodium hydroxide solution or a potassium hydroxide solution having an inlet (76) and an outlet (70) for use in the apparatus (10) of any one of the claims 1 to 10.
14. An anode (46) formed of titanium coated with a noble metal oxide for use in the apparatus (10) of any one of claims 1 to 10.
15. A cathode (34) formed of an austenitic stainless steel for use in the apparatus (10) of any one of claims 1 to 10.
16. A method of generating chlorine gas, hydrogen gas and a sodium hydroxide solution or a potassium hydroxide solution by electrolysis of a sodium chloride solution or a potassium chloride solution in apparatus (10) comprising an electrolytic cell (12) having an anodic compartment (20) containing an anode (46) and having an inlet (42) at a low point for the sodium or potassium chloride solution and an outlet (40) at a high point for the depleted sodium or potassium chloride solution, a cathodic compartment (18) containing a cathode (34) and having an inlet (30) at a low point and an outlet (24) at a high point for the sodium or potassium hydroxide solution, and an ion permeable membrane (50) separating the anodic compartment (20) and the cathodic compartment (18), a first container (14) for the sodium or potassium chloride solution having an outlet (52) connected to the inlet (42) of the anodic compartment (20) and an inlet (58) connected to the outlet (40) of the anodic compartment (20), and a second container (16) for the sodium or potassium hydroxide solution having an outlet (70) connected to the inlet (30) of the cathodic compartment (18) and an inlet (76) connected to the outlet (24) of the cathodic compartment (18), includes the steps of:
(a) providing in the anodic compartment (20) a sodium chloride solution or a potassium chloride solution and providing in the cathodic compartment (18) water or a sodium hydroxide solution or a potassium hydroxide solution;
(b) electrolysing the solutions to generate chlorine gas in the anodic compartment (20) and a movement of sodium or potassium ions through the ion permeable membrane (50) into the cathodic compartment (18), and to generate hydrogen gas and sodium hydroxide or potassium hydroxide in the cathodic compartment (18); and
(c) causing a circulation of the sodium chloride solution or potassium chloride solution between the anodic compartment (20) and the first container (14) by the generation of the chlorine gas in the anodic compartment (20) and causing a circulation of the sodium hydroxide solution or potassium hydroxide solution between the cathodic compartment (18) and the second container (16) by the generation of the hydrogen gas in the cathodic compartment (18).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8919181 | 1989-08-22 | ||
GB898919181A GB8919181D0 (en) | 1989-08-22 | 1989-08-22 | Apparatus for the electrolytic generation of chlorine |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0419052A1 true EP0419052A1 (en) | 1991-03-27 |
Family
ID=10662013
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90309226A Withdrawn EP0419052A1 (en) | 1989-08-22 | 1990-08-22 | Electrolytic generation of chlorine |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0419052A1 (en) |
AU (1) | AU6124490A (en) |
GB (1) | GB8919181D0 (en) |
ZA (1) | ZA899060B (en) |
ZM (1) | ZM4689A1 (en) |
ZW (1) | ZW15989A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999007919A1 (en) * | 1997-08-08 | 1999-02-18 | Inchem (Proprietary) Limited | Method and apparatus for generating a gas |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4308123A (en) * | 1979-11-30 | 1981-12-29 | Hydro-Chlor International, Inc. | Apparatus for the small-scale manufacture of chlorine and sodium hydroxide or sodium hypochlorite |
EP0046603A1 (en) * | 1980-08-27 | 1982-03-03 | Fernand Louis Oscar Joseph Chauvier | An apparatus for producing chlorine by electrolysis |
-
1989
- 1989-08-22 GB GB898919181A patent/GB8919181D0/en active Pending
- 1989-11-28 ZA ZA899060A patent/ZA899060B/en unknown
- 1989-12-01 ZW ZW159/89A patent/ZW15989A1/en unknown
- 1989-12-06 ZM ZM46/89A patent/ZM4689A1/en unknown
-
1990
- 1990-08-22 EP EP90309226A patent/EP0419052A1/en not_active Withdrawn
- 1990-08-22 AU AU61244/90A patent/AU6124490A/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4308123A (en) * | 1979-11-30 | 1981-12-29 | Hydro-Chlor International, Inc. | Apparatus for the small-scale manufacture of chlorine and sodium hydroxide or sodium hypochlorite |
EP0046603A1 (en) * | 1980-08-27 | 1982-03-03 | Fernand Louis Oscar Joseph Chauvier | An apparatus for producing chlorine by electrolysis |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999007919A1 (en) * | 1997-08-08 | 1999-02-18 | Inchem (Proprietary) Limited | Method and apparatus for generating a gas |
Also Published As
Publication number | Publication date |
---|---|
ZA899060B (en) | 1990-09-26 |
ZM4689A1 (en) | 1990-08-31 |
GB8919181D0 (en) | 1989-10-04 |
AU6124490A (en) | 1991-02-28 |
ZW15989A1 (en) | 1990-10-31 |
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