JPS5946315B2 - Hydrogen production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing hydrogen, and more particularly to a method for producing hydrogen by electrolysis of a halogen acid produced according to a novel principle using carbon such as coke or coal.

The present invention is particularly applicable to electrolysis methods using hydrogen chloride or hydrogen iodide.

The present invention will be described below with reference to this method, but the present invention can also be used in a wide range of other applications, and naturally hydrogen bromide can also be used. Electrochemically, it is applicable to a method using hydrogen fluoride, but since fluorine has a property of being highly active, it is not preferable to use such a specific halogen. The method can also be carried out in a gaseous state. Hydrogen production has recently received attention because hydrogen has various advantages as a directly heated fuel (MHD) or as a means for generating electrical energy in fuel cells.

For this reason, considerable efforts have been made to obtain large amounts of hydrogen for heat generation or power generation. Currently, the most common method for producing hydrogen is to electrolyze water, but this method requires a DC voltage of 2.0 volts or more for decomposition, so a considerable amount of electricity is required. Requires energy. As is well known, the higher the voltage required for electrolysis, the higher the cost of electrical energy for this method. Therefore, in order to reduce the cost of producing hydrogen, research has been conducted to improve the electrolysis method so as to reduce the voltage, that is, the electrical energy necessary for electrolysis. For example, the pressure in a water electrolyzer has been found to drop from slightly above 2.0 volts to a typical voltage range of about 1.6-1.7 volts. Furthermore, when hydrogen is produced by electrolysis of water, a large amount of electrical energy is consumed. This makes the electrolysis of water for hydrogen production an expensive process even though it is commercially viable in terms of the versatility of the hydrogen produced. The present invention relates to a new method for producing hydrogen by electrolysis in a bath using halogen acids such as hydrogen chloride, hydrogen bromide or hydrogen iodide.

According to this method, the voltage for electrolysis can be lowered, and the electrical energy required for this electrolysis method can be lower than that of water electrolysis methods that have been proposed so far. The method of producing hydrogen and its corresponding component halogen by electrolyzing hydrogen halides is a well-known technique.

This method is described in US Pat.
No. 42, No. 3236760, No. 3242065, and No. 3756930. As a novel feature, the present method does not implement a method for electrolyzing halogen acids, but for this general field, it provides an economical way to produce hydrogen at a cost substantially lower than the cost of electrolyzing water. The present invention relates to a novel method in which electrolytic methods can be carried out to generate electricity. Accordingly, the present invention relates to a process that utilizes the electrolysis of halogen acids to produce commercial quantities of hydrogen with an overall efficiency not previously available. As will be described later, the present invention implements a method that combines a method for efficiently producing an acid with a method for electrolyzing a halogen acid, and therefore a sufficient amount of acid can be produced at low cost. The method is carried out in a unit or apparatus. This unit consists of an electrolytic cell and an acid formation reaction area, and the reaction area may be housed within the electrolytic cell itself or may be communicated with by a conduit in which halogen acid for electrolysis is circulated in liquid or gaseous form. Good too.
To summarize above, the present invention uses a combination of a halogen acid electrolysis method and a novel halogen acid production method to achieve
Relating to a method for improving the production of hydrogen.

According to the present invention, an electrolytic cell for separating hydrogen from a halogen acid is used in combination with a reaction zone for producing acid using halogen decomposed by electrolysis.

According to a broad aspect of the invention, the reaction zone is adjacent to the anodic chamber of the electrolytic cell and utilizes the halogen, water, and reactants decomposed within the electrolytic cell to produce halogen acid. When the halogen acid is in solution, the solubility of the decomposed halogen in the acid solution and the hydrogenation efficiency of the present invention both determine the efficiency of the halogen acid for subsequent electrolysis to generate hydrogen. Helpful for replenishment. According to the invention,
The reaction in the reaction zone uses non-graphitic carbon that participates in the chemical reaction to produce the make-up halogen acid and produces carbon dioxide as a by-product.

Although preferred embodiments use solutions of halogen acids,
It is also possible to carry out gas processes. The liquid process will be discussed later. As used herein, halogen acids are hydrogen halides, ie acids that are not oxyacids. In the present invention, hydrogen is produced by electrolyzing a halogen acid in an aqueous solution. This method replenishes halogen acids by reacting electrochemically separated dissolved halogen with water in the presence of non-graphitic carbon. in this way,
Hydrogenation can be carried out at substantially higher concentrations and higher concentrations of halogen acids are obtained than with catalytic methods and other known methods of directly reacting halogens with water to obtain halogen acids.
Therefore, the present invention uses water and non-graphitic carbon to increase the concentration of halogen acid and increase the efficiency of the overall electrolysis process. According to the invention, hydrogen is separated for use outside the electrolyzer. Only water and carbon have to be introduced into the electrolyzer, and the operating voltage of the electrolyzer is substantially lower than that of electrolyzers used for water electrolysis.
Therefore, by simply using water as the charging material, hydrogen can be obtained with electrical efficiency that cannot be obtained with an electrolytic cell that generates hydrogen by directly electrolyzing water. In the present invention, water is first converted into halogen acid, and then hydrogen halide is efficiently converted into hydrogen and... halogen. The resulting halogen dissolves itself into the electrolyte in the electrolytic cell,
It reacts with water in the presence of the non-graphitic carbon and converts it into a solution of halogen acid that efficiently decomposes water. This novel method, detailed below and claimed, is not implied by the prior art.

For techniques for producing rogenic acids such as hydrogen chloride from heated carbon and water, see U.S. Pat.
No. 22, No. 1843196, No. 1843354, No. 1870308, and No. 2238896, but none of these patents describes a method for producing hydrogen, and also does not mention the use of free halogen. There is no mention of the use of carbon particles in the reaction zone of an electrolytic cell for producing halogen acids.

The present invention relates to a method for obtaining hydrogen from water without directly electrolyzing the water itself. US Patent No. 3995016
The issue states that by reacting water vapor and iodine vapor to produce hydrogen iodide, and decomposing this into hydrogen and iodine,
A method for producing hydrogen from water is described. In this method, water vapor and iodine vapor are reacted in the first step. The present invention relates to an electrolytic process using solutions of halogen acids, but such a process is not described in the conventional process of producing hydrogen from water by the use of iodine.

A method for producing hydrogen and oxygen from water without electrolyzing it is described in US Pat. No. 4,069,120. In this patent, a halogen and water are combined in gaseous form and the gas is irradiated to produce a halogen acid. However, this method does not utilize the halogen separated in the electrolytic cell to regenerate the insufficient acid in the electrolyte. Nor is there any mention of a reaction region using reactants.
US Pat. No. 4,021,323 relates to an apparatus for producing hydrogen by electrolyzing hydrogen iodide.

Here, hydrogen iodide is regenerated by a chemical reaction between hydrogen and iodine liberated in an aqueous solution. Since iodine is not dissolved in the electrolytic solution, this iodine is continuously replenished by reacting dissolved iodine with water in the presence of carbon or a catalyst, as in the present invention.

The above prior art described in connection with the basic embodiments of the present invention explains the background of the present invention and the novelty of the present simplified process for producing hydrogen from water and non-graphitic carbon. This shows that.

According to the present invention, a method is provided for producing hydrogen by electrolyzing a halogen acid produced by a reaction using an electrically separated halogen dissolved in a solution.
In this method, an electrolytic cell is provided that includes an electrolytic chamber containing a cathode that generates hydrogen and an electrolytic chamber that includes an anode that generates halogen. This electrolytic cell is filled with a rogenic acid solution, which is an electrolytic solution with a predetermined electrolytic voltage. The halogen acid in this electrolyte is regenerated in a continuous manner. The regeneration of this halogen acid consists of reacting the halogen, which has been electrolyzed in the anode electrolysis chamber and dissolved in the electrolyte, with the water of the electrolyte in the reaction zone adjacent to the anode periphery in the presence of non-graphitic carbon. . This reaction results in hydrogenation of the dissolved halogen and the addition of water and carbon replenishes the acid in solution. The carbon particles are non-graphitic carbon such as coke. By using halogen dissolved in the electrolyte,
It is now possible to circulate the electrolyte through the reaction zone, forming an integrated unit for continuous hydrogen production with continuous addition of water and coke. The main object of the present invention is to provide a method for producing hydrogen by an electrolytic method that has a lower operating voltage than water electrolysis. Another object of the present invention is to utilize a dilute solution of halogen acid in which halogen separated by electrolysis can be dissolved, and by adding water and carbon,
It is an object of the present invention to provide a hydrogen production method in which rogenic acid in an electrolytic solution is regenerated and replenished within a series of reaction zones.

Another object of the present invention is a hydrogen production method capable of converting coke and water into hydrogen by electrolysis, that is, supplying coke and water to an electrolytic cell using a halogen acid as an electrolyte, and producing hydrogen by electrolysis. We are here to provide you with a method.

The above advantages, those described in connection with the prior art, and other advantages will become apparent from the detailed description of the invention below.

FIG. 1 shows an apparatus or electrolytic cell for carrying out the invention for producing hydrogen from water and non-graphitic carbon particles.

According to the embodiment shown, the apparatus or vessel A includes a cathode 10 and an anode 12, and as the halogen, such as chlorine or iodine, is decomposed at the electrode 12, the halogen present around the anode 12 is removed from the halogen acid solution. It is immediately absorbed into the electrolyte E consisting of: When a suitable power source 11 applies a decomposition voltage to both ends of the electrodes 10 and 12, hydrogen halide is decomposed in the electrolytic solution, hydrogen is generated in the cathode periphery 14 of the electrolytic chamber 16 on the cathode side, and the electrolysis on the anode side is activated. Halogen is generated in the anode peripheral portion 20 of the chamber 22. Product name: Nafion (manufactured by Dupont)
The electrolytic chambers 16 and 22 are connected by a suitable device including a flow path 24 separated by a diaphragm 30 made of NafiOn. This diaphragm is made of 120th naphion and is approximately 0
．． The thickness is 2C34001 mm (10 mils).

The known linafion is a semipermeable diaphragm plastic material based on perfluorosulfonic acid. The cathode chamber 16 includes a lower drain pipe 32 and the anolyte chamber 22 includes a lower drain pipe 34.

The liquid level in both chambers is adjusted using appropriate valves 36, 38, respectively. These drains can be used to remove sludge and other unnecessary build-up at the bottom of each chamber 16,22. In the electrolytic chamber 22, which forms not only the anode periphery but also the reaction area for producing the supplementary halogen acid, there is a port 40 for introducing water and carbon particles C. A suitable valve or other regulating device 42 regulates the amount of carbon particles and/or water introduced into the reaction zone of the electrolysis chamber 22. It is desirable to introduce a halogen such as chlorine into the anodic electrolysis chamber 22 at the beginning of the reaction. A halogen population 44 is shown which is regulated by a suitable valve 46. An impeller 50 is provided in the electrolytic chamber 22.
is supported by a suitable journal mount 52, and the electrolytic solution E in the electrolytic chamber 22 is driven and stirred by a motor 54 so as to flow outward and upward. Therefore, the electrolyte in the reaction zone is stirred and continuously circulated. Therefore, the carbon particles C are maintained in a suspended state within the electrolytic solution in the electrolytic chamber 22. Actually, the electrolyte in the reaction area is about 8
Enough heat is generated by electrolysis to maintain the temperature above 0°C. This temperature facilitates chemical reactions in the anode periphery 20. It may be necessary to heat the electrolyte initially. This can be accomplished using a heating element 60 cross-connected to terminals 62 and 64. Electric thermal regulator 66 senses the temperature of the electrolyte via thermocouple 68 to regulate heating element 60 . During continuous operation the heat from electrolysis is sufficient to maintain uniform heat in the reaction zone. As mentioned above, the carbon particles C react with water to generate carbon dioxide, and this carbon dioxide is sent to the electrolytic chamber 2.
Accumulates at the top of 2. Substantially, carbon dioxide is the electrolyte E
Since carbon dioxide is insoluble in carbon dioxide, the carbon dioxide can be removed through a check valve 72 connected to a water trap 74 containing water 76 by providing a suitable vent 70. This water absorbs and dissolves halogens that may escape along with the carbon dioxide through vent 70. When the halogen concentration in water 76 increases, the halogen is separated from carbon dioxide by draining the absorbing liquid and replacing it with fresh water. Now, a hydrogen collection line 80 with a valve 82 is attached to the cathode electrolysis chamber 16, so that the electrolysis chamber 16 can be used continuously for suitable continuous use, such as direct combustion or fuel cell power generation.
Hydrogen gas can be extracted from

In the illustrated apparatus for implementing the construction method of the present invention,
Hydrogen is used as the fuel for fuel cell 90, which is also supplied with oxygen from a suitable oxygen source 92. In this case, an electrical potential is developed across conductors 94, 96 of fuel cell 90, and these conductors are used to supply any suitable load, illustrated as load 100. Electrolytic cell or device A is used to electrolyze the halogen acids in electrolyte E.

The concentration of halogen acid in the electrolyte is important in maintaining the general efficiency of cell A. The voltage across electrodes 10, 12 is lower than the water decomposition voltage. Therefore, the water used together with the halogen acid is not electrolytically decomposed by the electrolysis process. For this purpose, the water in the electrolyte constitutes a halogen acid solution in which electrolysis of the halogen acid takes place. One of the features of the present invention is the means for increasing the halogen acid concentration in the electrolyte. This requires hydrogenation of the halogen decomposed at the electrode 12 and dissolved in the electrolyte E. The halogen decomposed during the electrolysis process is immediately dissolved into a solution. Next, the dissolved halogen is hydrogenated in the electrolytic chamber 22 and becomes replenishing halogen acid for electrolysis. When tank A uses chlorine as the halogen, hydrogen chloride is produced in the electrolyte. Since the concentration of hydrogen chloride in the electrolyte is high, the amount of hypochlorous acid in the electrolyte is very small. Therefore, oxygen-related overvoltages or overpotentials are not a problem in the decomposition process between electrodes 10 and 12. To increase the concentration of halogen acids, agents that promote hydrogenation of halogens are used in the reaction zone of electrolytic chamber 22. Example 1
In preferred embodiments as described above, the drug is non-graphitic carbon particles of relatively small particle size. This carbon is oxidized to produce carbon dioxide as described above, thereby dissociating molecular hydrogen and providing the energy necessary to hydrogenate the halogen. By promoting the hydrogenation of halogens such as chlorine dissolved in electrolytic solution E, the concentration of halogen acid in the electrolytic solution is made much higher than in the process of absorbing other halogens into water and converting them into acids. I can do it. Traditionally, when halogens are absorbed into aqueous solutions, the acid concentration has been very low, about 3% or less. Therefore, absorbing halogens into water to make halogen acids has not been beneficial for efficiently electrolyzing the resulting acid solution. Chlorine, bromine and iodine can be continuously dissolved in an aqueous solution of acids produced by these halogens, and
The dissolved halogen is hydrogenated in the presence of carbon particles,
It has been found that replenishment halogen acids can be produced at concentrations greater than about 3%. It has been found that graphitic carbon promotes the hydrogenation of halogens dissolved in halogen acid solutions, and the rate of hydrogenation decreases rapidly as the supplemented acid concentration increases. This is shown in curve 1 of FIG.
Thus, in the case of hydrogen chloride, graphite-like carbon particles promote hydrogenation of chlorine relatively quickly until an acid concentration of about 5% is reached. This allows graphitic carbon to be used when the concentration of hydrogen chloride and other halogen acids is relatively low. However, the higher the concentration of halogen acid allows for a better and more efficient electrolysis process. If the carbon particles are non-graphitic carbon, they promote the hydrogenation of the dissolved...logen in the acid solution by at least 20%, as shown in curve 2 of Figure 2.
The hydrogenation rate does not decrease with increasing acid concentration up to ~30% acid concentration. For this reason, in the present invention:
Non-graphitic carbon particles are used as an energy source for hydrogenation of halogen dissolved in electrolyte E. This carbon becomes carbon dioxide and is consumed. This energy is used to produce hydrogen, which has far superior fuel and energy generation properties than carbon. For this reason, the present invention produces carbon dioxide as a by-product. By using non-graphitic carbon as shown in curve 2, the halogen concentration is increased substantially to about 20% hydrogen chloride concentration. The material used as the graphitic carbon in the curve of FIG. 2 is ATJ graphite manufactured by Union Carbide Corporation. The non-graphitic carbon is manufactured by Elco Spear Corporation (AircOSpee).
rCOrp. ) grade 37 coke carbon. Example 1 This non-graphite carbon was prepared as described below.
used in When this non-graphitic carbon is used, the concentration of halogen acid exhibits a substantially constant rate of increase even at low levels, and this ratio increases up to about 20% and above about 20% halogen acid. Continue for aqueous solutions of Therefore, non-graphitic carbon can be used to continuously hydrogenate dissolved halogens. It is not known why continuous hydrogenation of chlorine or other halogens is possible at high levels when using non-graphitic carbons, but this phenomenon is due to the overpotential of non-graphitic carbons in halogen acid solutions. It seems to be related to the characteristics.

This is illustrated in FIG. 3, where the overpotential or overvoltage in millivolts is compared for non-graphitic carbon and graphitic carbon. This graph was created by varying the concentration of hydrogen chloride, using graphitic carbon and non-graphitic carbon electrodes, and measuring the overpotential at these concentrations. Referring to this graph, both non-graphitic and graphitic carbons maintain relatively low overpotentials at hydrogen chloride concentrations up to approximately 20%. It can be seen that this 20% concentration is the concentration of hydrogen chloride at which hydrogen chloride begins to be liberated from water. next,
Graphitic carbon increases the overpotential considerably with respect to the halogen, whereas non-graphitic carbon maintains approximately the same overpotential or overvoltage level. Therefore, non-graphitic carbon continues to maintain a relatively low overvoltage or overpotential. In the present invention... hydrogenation of rogens occurs on the surface of carbon particles. The concentration of halogen acid at the particle surface is relatively higher than the concentration of the entire halogen acid solution, which is due to the generated acid accumulating on the reaction surface. As a result, non-graphitic carbon continues to hydrogenate to halogens at the carbon surface, while graphitic carbon has a higher overpotential or overpotential at this concentration level, with approximately 18% halogen in the area of the carbon surface. Hydrogenation is stopped when the acid concentration is reached. For graphitic carbon, this results in a halogen acid concentration of about 5% of the total electrolyte E, whereas for non-graphitic carbon, which can maintain a low overpotential or low overpotential, even if the concentration of halogen acid at the carbon surface is Hydrogenation continues even at concentrations of 18-20% or higher. The activity test described in Figure 3 involves overvoltage or overpotential, which is a voltage or potential that is typically greater than the theoretical potential that would cause a given electrochemical reaction to occur.

To obtain the diagram of FIG. 3 showing the relationship between graphitic and non-graphitic carbon with respect to overpotential factors, the overpotential between both electrodes and hydrogen chloride with various concentrations was measured at the electrodes. A current density of 1.55 mmA/CrA (10 mA/in²) was also used. As concentration increases, the overpotential at the non-graphitic carbon electrode remains roughly constant at about 7 millivolts at a 5% hydrogen chloride concentration, and roughly constant to about 8 millivolts at a 37% hydrogen chloride concentration. It went up like that. For graphitic carbon electrodes, the acid concentration in the solution ranges from 5% to 18%.
There was a millivolt overpotential. As the acid concentration is subsequently increased, the graphitic carbon electrode used in the test exhibits a very rapid increase in overpotential or overvoltage, reaching approximately 45 millivolts at a 24% hydrogen chloride concentration.
As the proportion of hydrogen chloride continued to increase, the graphitic carbon exhibited an overpotential of approximately 45-46 millivolts at acid concentrations of 24-37%. This relationship is shown in FIG. Therefore, since the overpotential of the non-graphitic carbon electrode hardly increased as the acid concentration increased in this test, it is possible to use non-graphitic carbon as the reactive particles in the anodic electrolysis chamber 22 in this invention. It has been theoretically proven that even if the acid concentration in the reaction region and the acid concentration on the surface of the carbon particles increase, the overpotential on the surface of the carbon particles hardly increases. As shown in Figure 3, experiments using graphitic carbon and non-graphitic carbon in a hydrogen chloride solution revealed that in the case of non-graphitic carbon, there was almost no change in the overpotential for halogens such as chlorine. It turns out there isn't. This indicates that the overpotential of the non-graphitic carbon particles remains approximately constant within the electrolytic chamber 22 of tank A shown in FIG. Therefore, this invention uses non-graphitic carbon along with all halogens such as chlorine, bromine and iodine. From the above description, the present invention uses a novel means of using coal or other carbon to electrochemically generate hydrogen and produce decomposed halogen acids.

The by-product is carbon dioxide. The decomposed halogen was dissolved in the electrolyte and then hydrogenated in the reaction zone of tank A, and the dissolved halogen in the circulating electrolyte was hydrogenated again by the use of carbon. A continuous process is created.
Hydrogen iodide has a much lower electrolysis voltage than water or hydrogen chloride, so hydrogen iodide is used more effectively than hydrogen chloride. Since the examples and examples relate to hydrogen iodide, both examples relate to the use of this halogen acid and to process improvements of the invention. FIG. 4 is a design modification of the preferred embodiment shown in FIG. 1 and is used for halogen acids as described above. In this embodiment, iodine is used as the halogen, but chlorine can also be used. Tank B has a cathode electrolysis chamber 110 and an anode electrolysis chamber 112. Electrolytic chamber 110
There is a cathode 114 inside, and similarly an anode 116 is connected to the electrolytic chamber 11.
Provided within 2. Conduit 118 connects electrolytic chambers 110 and 112 and includes a suitable septum 120 as described above. power supply 12
A DC power supply, shown as 2, applies a DC voltage across electrodes 114 and 116, with the voltage across the electrodes being approximately 0.6-0.
It is in the range of 7 volts DC voltage. This voltage was chosen to electrolytically decompose hydrogen iodide in electrolyte E. Of course, similar equipment can also be used with other rogonic acids such as chlorine and bromine. The hydrogen outlet 130 is connected to the electrolysis chamber 11
0 to a suitable storage or consumption device.
In this illustrated embodiment, a reaction tank 14 is provided separately from the electrolytic cell.
0 is installed and the electrolyte E is continuously circulated through this reaction tank by a suitable inlet 142 with a pump 144. This pump sucks in the dissolved halogen and electrolyte and discharges it into the reaction tank 140. The heat generated by the electrolysis process is sufficient to maintain the necessary reaction temperature within tank 140. Therefore, if there is no need to replenish heat and if tank B produces sufficient waste heat, the electrolyte in tank B will be heated to the boiling point. Outlet 146 conducts electrolyte E from reaction tank 140 to vessel B via a suitable filter 150. The filter 150 also removes unnecessary impurities from the electrolyte as it is returned to tank B. Central water intake 152 is used to collect electrolyte from tank 140. Since the impeller 154 circulates the electrolyte in the tank 140 in an outward direction, the carbon particles C are generally away from the water intake 152 and close to the filter 1.
It doesn't lead to 50. Referring to the figure, line 160 is used to introduce iodine or hydrogen iodide into the tank at the beginning of the process. Therefore, supplementary iodine is usually not required in continuous operating processes. Line 162 allows hydrogen chloride to be introduced into reaction tank 140 . As discussed below, hydrogen chloride has a substantially higher decomposition voltage than hydrogen iodide, so hydrogen chloride can be used with water in electrolyte E without being effectively electrolyzed. Hydrogen chloride has the following advantages. Hydrogen chloride reduces the voltage required between electrodes 114 and 116. Reducing the voltage also saves electrical energy, thereby increasing the electrical efficiency of devices incorporating the present invention. Line 164 is used to introduce water to reaction tank 140. The uses of water are as explained above. Referring to FIG. 4, non-graphitic carbon coke is introduced through line 166 and treated with nitric acid in tank 170. The carbon particles C are then washed in tank 172 and residual acid is removed via line 174. Therefore, the desired amount of carbon particles C of the coke treated with nitric acid is introduced into the reaction tank 140, so that the hydrogenation of the iodine dissolved in the electrolyte E fed from tank B via the inlet 142 is promoted. Ru. A suitable vent for carbon dioxide gas is shown as line 180 with check valve 182. Of course, a water trap may also be used, as described above with respect to the embodiment of tank A as shown in FIG. The general operation of tank B and the reaction tank 140 connected thereto is similar to that of tank A shown in FIG. The advantages of using nitric acid-washed carbon particles and hydrogen chloride in the iodine process are discussed below and covered in the examples. The device shown in FIG. 4 also generates hydrogen by using water and non-graphitic carbon particles. This carbon is consumed in the chemical process of producing the halogen acid required for the electrolysis process in tank B. Example 1 The anodic electrolysis chamber of tank A in FIG. 1 had a capacity of approximately 500 ml and was filled with 300 ml of water.

A cathode electrolysis chamber of approximately the same size was filled with water to the same height. The cathode was a platinum-coated graphite obtained by dipping the graphite in chloroplatinic acid and heating in air. This reduces the electrode overpotential with hydrogen. Similarly, the anode was made of graphitic carbon or graphite and boiled in nitric acid for 30 hours. The intermediate membrane between the electrolytic chambers is a 10 mil thick Dubon NafiOn 12 membrane.
It was formed with No. 0. The passage of hydrogen ions between the electrolytic chambers provides electrical continuity and a generally uniform acid concentration. Approximately 20 y of powdered coke was charged into the anode electrolysis chamber and the water was heated to approximately 80°C.

Coke is manufactured by AircOSpeer Corporation (AircOSpeerCO) as 37 grade coke carbon.
rp. ) was a standard non-graphitic carbon commercially available. The particle size is such that the particles pass through a standard 6 mesh screen and do not pass through a standard 14 mesh screen. The particles are then kept suspended in water by an impeller. Chlorine gas was then introduced into the slurry in the anode chamber and the Hel concentration continued to increase to between 20 and 25% by weight. To reach a HCl concentration of 25%, approximately 140 t
The reaction of 207 chlorine with 207 coke produces approximately 140 Vf) HCl in solution.

A DC voltage of 1.2 volts is applied between the electrodes so that a current of approximately 1.0 ampere is generated through the electrolyte.

A DC voltage of approximately 1.1 volts was used for acid decomposition. Hydrogen was generated at the cathode. The chlorine generated at the anode was recycled and reacted with water and carbon to make up hydrogen chloride. Carbon dioxide was separated by this step and passed to water tank 76. Since 20t of water and 6y of coke carbon are consumed per hour, 2f7 of hydrogen is generated per hour if the acid concentration is maintained at about 20% by weight.

After starting the process, the heat generated by the formula 12R (1: current strength, R: resistance) at both ends of the electrode was sufficient to maintain the electrolyte at a high temperature above 80°C.

The heater 60 was not connected during the process. Therefore, carbon 6
7 generates 2 f hydrogen per hour corresponding to a theoretical heating capacity of 265 Btu. The electrical energy consumed per hour is approximately 66 W/h, which is 226 Btu/h.
It can be converted to

226 Btu of electrical energy generates hydrogen with a conversion heating capacity of 264 Btu.

EXAMPLE The same basic process employed in Example 1 was carried out in cell A using hydrogen iodide as the electrolyte acid.

In this case, the voltage could be reduced to about 0.6-0.7 volts DC and about 27 cokes per hour were used as make-up non-graphitic carbon. In this example,
Electrical energy is 33W/h or 110Btu/h
Hydrogen 27 was generated when the heating capacity was 264 Btu with an input of . Factors for Efficient Hydrogenation A study of the halogens, ie, chlorine, bromine, and iodine used in the process described in Example 1, reveals that they are not related to the basic theory or operability, but have an effect on the efficiency of the process. We were able to point out some of the contributing factors.

Even concentrations of about 3% to 5% by weight allow hydrogenation of the halogens, allowing efficient operation of the system. The rate of hydrogenation of halogens is closely related to the free energy of the halogen acid, which is lowest for hydrogen chloride and highest for hydrogen iodide. Therefore, hydrogenation or acid production can be accomplished more quickly and easily with hydrogen chloride. However, the solubility of halogen in each acid is highest for hydrogen iodide and lowest for chlorine of hydrogen chloride. Considering the above factors, it is possible to discover some design changes regarding the rate of acid production in the coke-water-logen system. By passing coke through hot nitric acid and treating it with nitric acid, it is possible to increase the hydrogenation rate of halogen in the coke process.

The factor that increases the hydrogenation rate is on the order of 10 for iodine and substantially less for chlorine. The reason why this nitric acid treatment increases the hydrogenation rate of halogens is not understood, but it may be because nitric acid reduces halogen absorption into coke or non-graphitic carbon, i.e. carbon that has not been heated above about 2000°C. It is thought that there will be.
As a result of the reduced absorption, a reduced overpotential of the halogen appears on the carbon surface, which increases the hydrogenation rate. This process is more effective for iodine. In summary, one of the improvements in the basic method with Example 1 is to pre-treat the coke particles with nitric acid. Since the solubility of the halogen in the halogen acid is important for the hydrogenation of this invention, improved solubility is beneficial.

In fact, this can be achieved by adding sodium chloride to hydrogen iodide. This salt increased the solubility of iodine in aqueous hydrogen iodide solutions, but decreased the solubility of chlorine in hydrogen chloride. Therefore, the hydrogenation rate may be adjusted with a salt such as sodium chloride. The rate of reaction is also influenced by the free energy of the acid at the surface of the carbon particles.

As mentioned above, the rate of hydrogenation becomes progressively lower as the free energy becomes higher. It has been found that this rate can be influenced by adding a known low free energy level acid to a high free energy level acid. For example, when hydrogen chloride, which has the lowest free energy of the halogen under consideration, is added to a hydrogen bromide or hydrogen iodide based system, the hydrogenation rate increases. Similarly, hydrogen bromide increases the hydrogenation rate of hydrogen iodide systems. Apparently this phenomenon occurs due to the conversion of free energy on the carbon surface. Also, since these additional acids, ie, second halogen acids, require a higher voltage than the acid used as the base acid, these second halogen acids are not decomposed. In summary, measures such as treating the coke with nitric acid, using solubility modifiers, and adding a second halogen acid to the system can be used to control the efficiency of the basic system described in Example 1 and Beneficial.

In order to capture the halogen generated at the anode and hydrogenate it within the system, sufficient solubility of the halogen in the aqueous halogen acid solution is required. Furthermore, the low overpotential of non-graphitic carbon at higher concentrations allows hydrogenation steps beyond the usual lower concentrations obtained by simply reacting the halogen with water. By interacting the efficiency factors determined through experiments with the general process of Example 1, it is possible to construct a reaction with further improved electrical and chemical characteristics.

These factors affect the solubility and overpotential of the carbon to control and facilitate hydrogenation at higher acid concentrations, for example in the range of 5 to 25% by weight hydrogen chloride. EXAMPLE Another example was performed using the above-described efficiency factors obtained in the experiment.

In this example, in a system similar to the example in which hydrogen iodide was used as the electrolyte, three factors that varied the hydrogenation rate were taken up. Hydrogen was obtained from an electrolyte produced by hydrogenation of iodine, which is the preferred system of the present invention. In this example, tank B as shown in FIG. 4 was used. The non-graphitic carbon or coke was treated with nitric acid and then heated to remove excess nitric acid. Although this increased the iodine hydrogenation rate, the traces of nitric acid residue on the carbon particles had no obvious deleterious effect on the overall system. In this example, a small amount of titanium tetrachloride was added, which is a salt to further increase the hydrogenation rate and reduce the corrosivity of the acid mixture. This salt increased the solubility of electrolyzed iodine. A considerable amount of hydrogen chloride was used along with the hydrogen iodide electrolyte. Hydrogen chloride lowered the decomposition voltage of the hydrogen iodide electrolyte, but since the voltage across the electrodes was about 0.3 volts DC, the hydrogen chloride did not undergo electrolysis. If less hydrogen chloride was used, the voltage of the hydrogen iodide electrolyzer was approximately 0.6-0.7 volts DC. This voltage of 0.3 volts is sufficient to electrolyze hydrogen iodide, but approximately 1.2-1.
This is insufficient for hydrogen chloride electrolysis, which requires 3 volts. In order to achieve a decomposition voltage of 0.3 volts in a hydrogen iodide-only electrolyzer with no added hydrogen chloride, the hydrogen iodide concentration in water must be about 50% by weight. In this example, in order to decompose the hydrogen iodide electrolyte at 0.3 volts, 20
% hydrogen chloride and 1% hydrogen iodide by weight were required.
Therefore, this example increased the hydrogenation of iodine, reduced the decomposition voltage of hydrogen iodide, and reduced the required amount of iodine, which is considerably more expensive than chlorine. This example uses: (1) Elcospear grade 37 coke carbon, which was boiled in constant boiling nitric acid for 8 hours and then washed in water; (2)
Contains 20% by weight hydrogen chloride, (3) 1% by weight hydrogen iodide, (4) 1% by weight titanium tetrachloride, and (5) residual water. The temperature of the tank was about 108° C., and the electrolyte was stirred to prevent carbon particles from precipitating.

The decomposition voltage to generate hydrogen was 0.3-0.4 DC volts and hydrogen was generated at a current of 2 amps. The tank was made airtight to prevent oxidation of the hydrogen iodide electrolyte. Of course,
Other design changes may be made in the various illustrated steps in carrying out the invention without departing from the spirit of the invention.

The gist of this invention relates to the concept of generating hydrogen by electrolyzing a halogen acid electrolyte, and since this electrolyte absorbs the decomposed halogen and circulates the absorbed halogen along with the electrolysis in the reaction zone, The halogen is hydrogenated again using water and carbon. The decomposed hydrogen itself is not used for rehydrogenation within the system, but the entire amount is used for purposes outside the system, such as heating or power generation, as shown in the two embodiments. Design Modifications FIG. 4 shows design modifications to the preferred embodiment.

In this embodiment, tank D has electrodes 204 on both surfaces, respectively.
A container 200 having a NafiOn septum 202 attached thereto. When a power source is applied to both ends of the conductive wires 210 and 212, the diaphragm exhibits an electrolytic function.
Gaseous acid vapor is supplied from the electrolytic chamber on the anode side to the electrode surface of the diaphragm to enable electrolysis to generate halogen gas in the electrolytic chamber 220. At the same time, hydrogen is separated and stored in the electrolysis chamber 222 and exits through the conduit 224. Free halogens, such as chlorine, are removed from the electrolytic chamber 220 by means represented as a pump or proar 232 in conduit 234.
The reaction tank or reaction area 230 is in a gaseous state.

Steam from conduit 234 is forced into a chamber 240 bounded by an upper bed of water 242 and non-graphitic carbon 244. A plurality of burners 250 in line 252 heat water 242 to boiling point to generate steam. This water vapor, along with the steam from conduit 234, reacts with the carbon and hydrogenates the chlorine to form hydrogen chloride vapor. This hydrogen chloride vapor is transferred to the electrolysis chamber 220 through a conduit 260.
The chlorine in continuous circulation is decomposed by electrolysis at the bottom of this electrolysis chamber. Condenser 270 removes water vapor. Due to the heat generated during the electrolysis process, the electrolysis chamber 2
20 and conduit 234 to maintain the vaporized state of the circulating components. Vent 272 having a diameter of approximately 1/20 of the area of conduit 234 to remove carbon dioxide from the closed loop.
in the area of maximum cooling of the circuit.

Condenser 274 condenses the water vapor which absorbs all the hydrogen chloride. A large amount of carbon dioxide containing a small amount of halogen then passes through a condenser. If necessary, halogen is removed by dry carbon bed 276.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for carrying out the method constituting the present invention, and FIG. 2 is a graph showing the hydrogenation rate of chlorine on non-graphitic carbon and graphitic carbon used in the present invention. 3 is a graph showing the overvoltage characteristics comparing non-graphitic carbon and graphitic carbon, and FIG. 4 is a more detailed apparatus for carrying out the method constituting a preferred embodiment of the present invention. FIG. 5 is a schematic diagram showing a system for using the invention in gaseous form.

Claims (1)

[Claims] 1. In a method for producing hydrogen by electrolyzing a halogen acid electrolyte, a halogen acid electrolyte in which halogen produced at an anode is dissolved is mixed with non-graphitic carbon particles in a liquid phase at a temperature of 80°C or higher or A method for producing hydrogen, which comprises converting halogen into halogen acid by reacting in a gas phase, and repeatedly using the halogen acid electrolyte as a halogen acid electrolyte. 2. The method for producing hydrogen according to claim 1, characterized in that a halogen acid electrolyte in which a halogen is dissolved is reacted with suspended non-graphitic carbon particles in an electrolytic chamber on the anode side of an electrolytic cell. 3 A halogen acid electrolyte in which a halogen is dissolved is introduced into a reaction zone separate from the electrolytic cell where non-graphitic carbon exists, and the halogen is converted into halogen acid, which is repeatedly used as a halogen acid electrolyte. A method for producing hydrogen according to claim 1. 4. The method for producing hydrogen according to claim 1, wherein the non-graphitic carbon particles have a size that allows them to pass through a 6-mesh screen. 5. The method for producing hydrogen according to claim 1, characterized in that a second halogen acid having a decomposition voltage substantially higher than the electrolysis operating voltage of the halogen acid electrolyte is added to the electrolyte. 6. The method for producing hydrogen according to claim 1, wherein the halogen acid is hydriodic acid. 7. The method for producing hydrogen according to claim 6, wherein the second halogen acid is hydrochloric acid. 8. The method for producing hydrogen according to claim 1, characterized in that the non-graphitic carbon particles are pretreated by passing them through a nitric acid solution and the nitric acid is removed by washing.