JPH04350188A - Countercurrent electrolytic reaction vessel - Google Patents

Abstract

PURPOSE:To save the requisite power and to realize a high-efficiency reaction vessel by countercurrently circulating an oxidizing agent and a reducing agent on both sides of a diaphragm in the vessel. CONSTITUTION:Steam is introduced into a reaction vessel from an inlet 21 and reduced in a cathodic reaction chamber 23, and hydrogen is discharged from a product outlet 22. Meanwhile, carbon monoxide as a reducing agent is introduced from an inlet 24, oxidized in an anodic reaction chamber 26 and allowed to flow in the opposite direction to the steam. The oxygen extracted from steam on the cathode is passed through an electrolyte diaphragm 27 and used to oxidize CO on the anode. At this time, although the hydrogen concn. is increased in the cathodic reaction chamber 23, oxygen moves spontaneously since there is more than the equilibrium concn. of oxygen in the anodic reaction chamber 26 at all times.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a countercurrent electrolytic reaction tank. More particularly, this invention relates to an improved electrolytic reactor in which redox reactions can be carried out as electrolytic reactions with high efficiency and with conserved power.

0002

2. Description of the Related Art In a general reactor for performing a redox reaction, reaction products are mixed together, and in the case of an equilibrium reaction, unreacted raw materials are also mixed into the product. To explain this using Figure 1 as an example of the production of hydrogen from water vapor using a water gas equilibrium reaction, water vapor and carbon monoxide are supplied to the reactor inlet (1), and as a result of a predetermined equilibrium reaction, the water vapor is part is reduced and a mixture of hydrogen, water vapor, carbon monoxide and carbon dioxide is obtained as a product stream at the reactor outlet (2). A redox reaction proceeds in the reactor (3). On the other hand, in an electrolytic reaction apparatus in which an electrolyte is fixed and used as a diaphragm, as illustrated in FIG. ) flows out as product hydrogen. Oxygen in the water vapor moves as ions through the solid electrolyte membrane (17) and reduces carbon monoxide on the anode. Anode reaction chamber (16)
Carbon monoxide is supplied from the reducing agent inlet (14), and carbon dioxide is discharged from the oxide outlet (15). That is, an oxidation reaction is performed on one anode of the diaphragm (17), and a reduction reaction is performed on the other, and the respective reaction products can be obtained in a separated state. In this electrolytic method, by supplying electric power between the electrodes, reactions that cannot be expected from chemical equilibrium can be performed. However, as such conventional methods, only a few ideas have been found for using a reducing agent in the electrolysis of water vapor using a solid electrolyte electrolytic cell. Since the reaction can only proceed spontaneously until it reaches thermodynamic equilibrium, in order to obtain high reaction efficiency, that is, to decompose most of the water vapor into hydrogen, it is necessary to supply electricity between the electrodes. Oxygen ions must be forcibly moved. Furthermore, in order to obtain extremely high efficiency, a high electrolytic voltage is required, which is not only uneconomical but also causes damage to the reaction vessel due to electrolysis and redox reactions of the electrolyte. Therefore, the result is usually a mixture of unreacted water vapor and hydrogen in the product, while a mixture of carbon monoxide and carbon dioxide is obtained from the anode side, requiring further separation steps or removing raw materials. This will result in waste.

0003

[Problems to be Solved by the Invention] The present invention solves the drawbacks of the conventional apparatus in an electrolytic reaction tank that uses an electrolyte as a diaphragm as described above, performs each redox reaction at a high rate, and at the same time does not meet the necessary requirements. The object of the present invention is to provide an improved electrolytic reaction cell that can significantly reduce the amount of power used and prevent deterioration of the electrolytic cell due to voltage supply.

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides an electrolytic reaction tank having an electrolyte diaphragm, in which reactants of an oxidizing agent and a reducing agent are placed on both sides of the diaphragm in the tank. Provided is a countercurrent electrolytic reaction tank characterized by forming a flow system that allows countercurrent flow in opposite directions.

That is, the present invention comprises an electrolytic reaction tank consisting of two elongated reaction chambers, an anode chamber and a cathode chamber, separated by an electrolyte diaphragm, and an oxidizing agent in the cathode chamber and a reducing agent in the anode chamber. The purpose is to cause ions to spontaneously move through the electrolyte by causing countercurrent flow in the electrolyte, and to obtain a high-concentration product containing no unreacted substances from the outlet of each reaction chamber.

[0006] The electrolytic reaction tank according to the present invention is shown in FIG.
To explain this, water vapor, which is a raw material, is supplied from the raw material inlet (21) of the reaction tank, flows through the cathode reaction chamber (23) while being reduced at the cathode, and flows out as product hydrogen from the product outlet (22). On the other hand, oxygen monoxide, which is a reducing agent,
Supplied from the reducing agent inlet (24), the anode reaction chamber (26)
The water vapor flows in the opposite direction while being oxidized at the oxide outlet (
25). Oxygen extracted from water vapor at the cathode flows as ions through the electrolyte membrane (27) and oxidizes carbon monoxide at the anode. At this time, the cathode reaction chamber (23)
In this case, the water vapor concentration decreases and the hydrogen concentration increases along the flow, but in the anode reaction chamber (26) corresponding to the cathode reaction chamber (23), carbon monoxide always exists at an equilibrium concentration or higher. The movement of oxygen proceeds spontaneously from the cathode to the anode. Since almost pure carbon monoxide is present on the corresponding anode at the outlet of the cathode reaction chamber (23), even a small amount of residual water vapor is reduced, and almost complete conversion of water vapor to hydrogen can be achieved without the need for electricity. It will be done. On the other hand, when the corresponding stoichiometric amount of carbon monoxide is fed into the anode reaction chamber (26), this conversion to carbon dioxide also takes place almost completely. Theoretically, this can be achieved regardless of the equilibrium constant of chemical equilibrium.

[0007] The anode and cathode are electrically shorted or connected to an auxiliary power source. A current flows through this circuit according to the amount of reaction. If the reaction does not proceed sufficiently due to the resistance of the electrolyte, it is necessary to supply external power, but since the voltage is extremely small, power consumption is low, and there is little risk of damage to the electrodes or electrolyte due to undesirable reactions. If the reaction proceeds sufficiently spontaneously, it is also possible to extract electricity from this circuit. If this is actively used to make this device into a fuel cell, the effect of the present invention is that the utilization efficiency of fuel and oxidizer is high, that is, the amount of fuel and oxidizer discharged unused is reduced. You can expect good results.

Examples of the electrolyte membrane that can be used in the present invention include oxides of alumina, zirconia, titania, etc., and composites thereof. EXAMPLES Hereinafter, the electrolytic reaction vessel of the present invention will be described in more detail with reference to Examples.

[0009]

[Embodiment] FIG. 4 shows an embodiment of an electrolytic reaction tank to which the present invention is applied. In this example, stabilized zirconia ceramics that operate at high temperatures were used for the electrolyte diaphragm (37), platinum was used for the electrodes, and the reactions involved reducing water vapor to hydrogen and oxidizing deuterium. Reactants (water vapor, hydrogen) flowed inside and outside the ceramic tube. Steam is supplied from the raw material inlet (31), and deuterium is supplied from the reducing agent inlet (34).
It was introduced more. Hydrogen produced by the reaction in the cathode reaction chamber (33) was recovered from the product outlet (32), and heavy water was discharged from the oxide outlet (35). Almost no external power was required.

It has been experimentally confirmed that under these conditions, the reduction of water vapor to hydrogen and the oxidation of deuterium can be performed simultaneously and with a small voltage.

[0011]

According to the present invention, as explained in detail above, redox reactions can be carried out with high efficiency using saved electric power.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating a conventional general redox reaction.

FIG. 2 is a block diagram showing a conventional electrolytic reaction tank.

FIG. 3 is a block diagram illustrating an electrolytic reaction tank of the present invention.

FIG. 4 is a block diagram illustrating an electrolytic reaction tank as an example of the present invention.

[Explanation of symbols]

1　Reactor inlet 2 Reactor outlet 3 Reactor 11　Reactor inlet 12 Reactor outlet 13 Cathode reaction chamber 14 Reducing agent inlet 15 Oxide outlet 16　Anode reaction chamber 17 Solid electrolyte diaphragm 21, 31 Raw material inlet 22, 32 Product outlet 23, 33 Cathode reaction chamber 24, 34 Reducing agent inlet 25, 35 Oxide outlet 26, 36 Anode reaction chamber 27, 37 Electrolyte diaphragm

Claims (1)

[Claims] [Claim 1] An electrolytic reaction tank having an electrolyte diaphragm, characterized in that a flow system is formed on both sides of the diaphragm in the tank to allow reactants, oxidizing agent and reducing agent, to flow countercurrently in opposite directions. Countercurrent electrolytic reaction tank.