FR2856080A1 - Procedure for producing hydrogen and oxygen from water has one electrode formed by a number of plates that are fed with current independently and in succession - Google Patents

Abstract

Electrodes (20, 30, 32) immersed in aqueous electrolyte and connected by conductors to power supply delivering 9 amps. At least one electrode, a cathode (32) is made up of a number of separate plates (32-1 to 32-9) fed with a current independently of one another and in succession, through a distributor (36). Each plate is fed with current for a given amount of time, ensuring that the tension in each plate stays above a pre-set threshold value. The procedure uses electrodes (20, 30, 32) immersed in an aqueous electrolyte and connected by conductors to a power supply delivering 9 amps. At least one of the electrodes, i.e. a cathode (32) is made up of a number of separate plates (32-1 to 32-9) that are fed with a current independently of one another and in succession, through a distributor (36). Each plate is fed with current for a given amount of time, ensuring that the tension in each plate stays above a pre-set threshold value. Each of the separate plates is fed through a triac switch to control the amount of energy delivered to it. The procedure takes place in a metal tank with two outer compartments (26, 28) to collect the hydrogen, connected to a central tank in which the oxygen is collected.

Description

PROCEbE bE PRODUCTION bE GAS FROM bE WATER AND DEVICE bE IMPLEMENTATION

PROVEb

  The present invention relates to a method of producing gas from water and the possibility of dissociation into hydrogen and oxygen.

  The invention also covers the associated device allowing the implementation of the method.

  The dissociation of water by means of two electrodes traversed by an electric current has been known for a long time. Indeed, from water, the stoichiometric composition leads to obtaining one volume of oxygen for two volumes of hydrogen.

  On the other hand, these gases such as oxygen and even more hydrogen are difficult to store and present risks of flammability and explosion which are not compatible with certain uses. be more, as they are molecules of small dimensions, the containers are necessarily delicate to manufacture and in all cases, these containers are of a high cost price, especially for large volumes and for long storage periods .

  It would therefore be useful to be able to produce the gases quickly and in fixed or mobile units, at the place of their use.

  In addition, if the theoretical production yield of gas is known, the current means of production are far from achieving them. As a result, the consumption of electricity remains too high, which increases the cost of production all the more.

  Finally, the raw material, namely water, is low in cost and available everywhere. As for electricity, it can be produced in various ways, which is not a problem either.

  The uses of these two gases are extremely numerous and for the future, they could largely replace oil, notably thanks to their energy power. These gas mixtures could in particular become vehicle fuels.

  In the context of tests conducted to improve production yield, surprising results have been recorded with regard to improving yield. To this end, the process for producing hydrogen and oxygen from the decomposition of water, comprises, in a known manner, electrodes immersed in an aqueous, conductive electrolyte, a current source delivering a given power, c 'is to say a product of a voltage by an intensity, and this method is characterized in that, at equal power delivered, there is provided a combination of several plates for at least one of the electrodes and in that the these plates are fed independently of each other, successively.

  According to another characteristic, each plate is supplied with a time interval such that the voltage in each plate remains above a set point.

  The invention also covers the device for producing hydrogen and oxygen from the decomposition of water, for the implementation of this process and comprises two electrodes, at least one of which comprises several plates and a module for supply of these plates by circular permutation so as to maintain the voltage above a set point.

  According to a particular embodiment, the plate supply module comprises a chaser.

  According to another characteristic of the invention, a triac is provided upstream of each plate to control the amount of energy delivered to each plate.

  This method of controlling the supply of electrodes with a view to dissociation of the water is now described in detail, according to a particular, nonlimiting embodiment, with reference to the appended drawings which represent: - Figure 1, a view of a device for dissociating water according to the prior art, and - Figure 2, a view of a comparative assembly of the productions of the device 10 of the prior art and of the device according to the present invention, A device for the prior art is described in FIG. 1.

  This device comprises, in a known manner, a device 10 for supplying electricity, continuously, of a power PA, of a set 12 of single electrodes for each pole, 12A for the anode connected to the pole (+) and 12C for the cathode connected to the 15 pole (-).

  The 0- ions are attracted to the anode while the H + ions are attracted to the cathode. As a result, the oxygen gas O2 is released at the anode and the hydrogen gas H2 is released at the cathode.

  The electrical supply is a supply from direct current since the longer the electrodes are supplied, the greater the quantity of gas produced. There is indeed a direct proportionality subject to yield.

  This installation known from the prior art must now be compared to that of the invention.

  For this purpose, the applicant proposes an experimental installation represented schematically in FIG. 2 making it possible to compare the two operations in an objective manner.

  This installation consists in providing an anode 20 in a first common tank 22 connected by the same electrolyte 24 through the walls of the tank by means of fluid communications.

This tank is vented.

  On either side of this tank, there is provided on the left of the figure a closed tank 26 operating according to the process of the prior art and on the right of the figure a closed tank 28 operating according to the process of the present invention.

  The tank 26 comprises a cathode 30 which generates hydrogen gas collected in the sky from this closed tank. The electrode 30 is made of metallic material, in this case steel, and is in the form of a thin plate of surface s.

  The tray 28 comprises a multiplicity of cathodes 32, in this case 9 cathodes, each of these electrodes being made of metallic material, in this case steel as for the electrode of the tray 26.

  The surface of each electrode 32 is identical to that S of the electrode 30.

  The tank 28 is also a closed tank allowing the hydrogen produced to accumulate in the sky of this tank.

  The two closed tanks are connected to the common tank and there is also provision for discharging the electrolyte during the hydrogen accumulation phase. This is done on an experimental basis because in production, it is obviously the gas which escapes and which is collected, the level of the electrolyte being on the contrary kept constant.

  There is also provision for a power supply for the assembly. This power supply includes a common source 34 which delivers an alternating current from the network, for most networks, 200 V at a frequency of 50 Hz.

  This voltage is reduced to 12 V for the prior art and 6 V for the device according to the present invention. The frequency is also reduced to 25 Hz for both.

  On the other hand for the sake of comparison, the powers consumed are completely identical.

  The anode is connected in common with the two circuits.

  A power consumption of 54W is provided, which corresponds to an intensity of 4.5 amperes for the prior art and an intensity of 9 amperes for the device according to the present invention.

  According to the known method of the prior art, the single plate cathode 30 of the prior art is supplied with current continuously since it is unique. This plate receives all the available power.

  The circuit of the device according to the present invention differs from the previous one in that it comprises means 36 for distributing electrical energy which ensure a successive and periodic supply of each of the plate cathodes 32.

  Such means are known in electricity and are more commonly called a chaser.

  Thus, the first cathode plate 32-1 is supplied for a period t, then its supply is cut. The cathode plate 32-2 is in turn supplied for a duration t identical to the supply duration of the preceding plate 32-1.

  When the last cathode plate, 32-9 in the embodiment shown, has been supplied, it is the turn of the first 32-1 to be supplied again.

  It is clearly observed throughout the duration of the test that the power consumed P is identical in the two supply circuits since it corresponds to the amount of energy consumed.

  After a given time T, there is a much higher production of hydrogen V by the multiple electrode 32 made up of 9 cathodes than the production v by the single electrode 30.

  Explanations can be put forward without being the sole and / or main reason for this.

  We know that when a pulse is emitted in an alternating current, it is a sinusoidal current which is far from being a square signal.

  As a result, there is a slope for both the rise and the fall to reach the full value of the voltage and the zero voltage.

  This is how it is interesting to work only in the tension zone which is located close to the maximum tension without ever going down to a zero value.

  Thus with the chase, it is possible to provide, as a function of the number of electrodes, of the slope, of the frequency, a current distribution such that each plate cathode 32 is supplied by the chase with a voltage close to the maximum without letting the voltage drop. in each plate below a given value.

  During the period during which the voltage is too low in a plate 32, it is the following which are supplied in the optimum voltage range.

  On the other hand, the single cathode plate 30 thus supports a non-productive period from which it cannot escape.

  The number of plates must therefore be optimized as a function of the supply parameters.

  In the case of a power supply with a voltage of 6 V and 9 plates with a minimum voltage of 1.4 V minimum below which it should not be lowered, an average operating voltage of 2.06 V is obtained. Vmoy ,, enne = 1.4 + (1/9) x 6 = 2.06 V As 9 plates are provided, an effective power of 18.54 W is obtained, which corresponds to an overall efficiency of 33%.

  As the 9 plates operate continuously at this yield, we actually obtain a working power of 9 x 18.54 or 166.84 W. We then observe that the production power is substantially three times that of the single plate permanently supplied.

  In practice, the measurement of the volumes of hydrogen produced by the multiple cathode electrode and the single cathode shows exactly the same differential.

  At the start of the implementation of the method, there is also a certain delay which is only the consequence of the implementation of the method.

  Another explanation coming in addition or in substitution can be given concerning these observed yields. In fact, when there is only one production surface and this plate is supplied with a given power, this dissociates the water in the immediate vicinity but there is a phenomenon of saturation of the surface of the plate with bubbles which provide local electrical insulation of the plates, limiting the dissociation capacities. It has been found that each bubble undergoes a phenomenon of retention on the surface of the plate, at the point where it is generated until it reaches a certain volume sufficient for the Archimedes' push to ensure detachment and ascent. from the bubble to the surface.

  In the case of multiple plates, even if the phenomenon is identical, the bubbles have the possibility of peeling off from the surface while the chaser 20 ensures the supply of the other plates so that when the plate in question is again fed, it is much more operational.

  In order to allow an optimized supply of all the plates, this at each passage, provision is made for the interposition of an energy source, means for regulating the tension, means for lowering the tension if necessary, a module d 'supply of the plates by circular permutation of the chase type and triacs to ensure a controlled supply of the amount of energy of each plate.

  Of course, it has been mentioned throughout the description the term plate which is common in this technical field but each electrode can take any suitable form, in particular depending on the configuration of the electrolyte tank.

Claims (5)

REVENDITCATIONS   1. A method of producing hydrogen and oxygen from the decomposition of water, comprising electrodes immersed in an aqueous, conductive electrolyte, a current source delivering a given power, that is to say a product of a voltage by an intensity, characterized in that, at 5 equal power delivered, provision is made for a combination of several plates for at least one of the electrodes and in that these plates are supplied independently of one another, successively .   2. Method for producing hydrogen and oxygen according to claim 1, characterized in that each plate is supplied with a time interval 10 such that the voltage in each plate remains above a set point.   3. Device for producing hydrogen and oxygen from the decomposition of water, for implementing the method according to one of claims 1 or 2, characterized in that it comprises two electrodes, one of which at least comprises several plates and a module for supplying the plates by circular permutation so as to maintain the voltage above a set point.   4. Device for producing hydrogen and oxygen according to claim 3, characterized in that the plate supply module comprises a chaser.   5. Device for producing hydrogen and oxygen according to claim 3 or 4, characterized in that it comprises upstream of each plate a triac to control the amount of energy delivered to each plate.