US20090026069A1

US20090026069A1 - Hydrogenation electrolysis apparatus

Info

Publication number: US20090026069A1
Application number: US11/878,444
Authority: US
Inventors: Wen-Chen Liao; Jen-Hung Chen
Original assignee: Institute of Nuclear Energy Research
Current assignee: Institute of Nuclear Energy Research
Priority date: 2007-07-24
Filing date: 2007-07-24
Publication date: 2009-01-29

Abstract

The present invention provides an apparatus for rapidly grow zirconium hydride (ZrH₂) on a Zr tube. ZrH₂is obtained through electrolyte in a hydrogenation. The electrolyte uses As₂O₃as a catalyst to speed up the deposition of ZrH₂.

Description

FIELD OF THE INVENTION

The present invention relates to a hydrogenation; more particularly, relates to an electrolysis apparatus for speeding up a hydrogenation of zirconium hydride (ZrH₂).

DESCRIPTION OF THE RELATED ARTS

Nuclear power is one of the most important power source nowadays. A chain reaction of U²³⁵is utilized to release a tremendous sum of power. In general, U²³⁵is filled in a zirconium (Zr) tube for a nuclear fission reaction. Because the Zr material has a small neutron absorption cross-section, neutron is not easily trapped by the Zr tube and thus the fission reaction continues. In the other hand, the Zr tube has a good resist to corrosion and a good mechanical strength under high temperature. Thus, the Zr tube is used as a protection for U²³⁵material.
In a nuclear power generation, water is usually used to transfer power obtained from the nuclear fission reaction. However, the Zr tube would react with water to obtain hydrogen through an oxidation reaction, whose reaction formula is as follows:
Zr+2H₂O→ZrO₂+2H₂ (1)
Then, the Zr tube is processed through a hydrogenation to obtain zirconium hydride (ZrH₂), whose reaction formula is as follows:
Zr+H₂→ZrH₂ (2)
As a result, a hydrogen embrittlement is happened to the Zr tube, and crack or hole may appear to the Zr tube to leak the U²³⁵. Thus, a study on the hydrogen embrittlement of the Zr tube is an important issue. A ZrH₂layer having a different thickness must be obtained in advance for further examining the zircaloy cladding specimen.
A prior art is a gas hydrogenation process to obtain ZrH₂in a Zr tube. However, a specimen containing hydrogen with uniformity and high-density is obtained ‘inside’ a Zr tube; and an ‘outside’ ZrH₂layer has to be obtained in another way.
An other prior art is a hydrogenation through electrolysis. Although a great sum of hydrogen is left on the Zr tube, the time spent is too long. It becomes a big issue for this prior art on shortening the reaction time. Hence, the prior arts do not fulfill all users' requests on actual use.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to speeding u p a hydrogenation of zirconium hydride (ZrH₂) to obtain ZrH₂on a surface of a Zr tube.
To achieve the above purpose, the present invention is a hydrogenation electrolysis apparatus, comprising a first electrode, a second electrode, an electrolyte solution and a direct current (DC) power source, where the first electrode and the second electrode is put in the electrolyte solution; the anode of the DC power source is coupled to the second electrode and the cathode of the DC power source is coupled to the first electrode; the first electrode is made of Zr and the electrolyte solution comprises an acidic solution and As₂O₃the density of As₂O₃is 0.001M; the acidic solution is a sulfuric acid (H₂SO₄) solution and has a density of 0.5M; the electrolyte solution has a temperature of 85° C.; the first electrode has a tube shape and the second electrode has a tube shape or a curved-plate shape; the second electrode is made of platinum; and the As₂O₃is functioned as a catalyst in the electrolyte solution to speed up a hydrogenation for rapidly obtaining ZrH₂on the first electrode. Accordingly, a novel hydrogenation electrolysis apparatus is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from the following detailed descriptions of the preferred embodiments according to the present invention, taken in con junction with the accompanying drawings, in which

FIG. 1 is the view showing the first preferred embodiment according to the present invention;

FIG. 2A is the view showing the second preferred embodiment;

FIG. 2B is the view showing the first electrode;

FIG. 2C is the view showing the second electrode; and

FIG. 3 is the view showing the thickness change in ZrH₂during the deposition.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

The following descriptions of the preferred embodiments are provided to understand the features and the structures of the present invention.
Please refer to FIG. 1, which is a view showing a first preferred embodiment according to the present invention. As shown in the figure, the present invention is a hydrogenation electrolysis apparatus 100, comprising a first electrode 110, a second electrode 120, an electrolyte solution 130 and a direct current (DC) power source 140, where the first electrode 110 and the second electrode 120 are dipped in the electrolyte solution 130; the DC power source 140 is coupled to the second electrode 120 with an anode and is coupled to the first electrode 110 with a cathode; the first electrode 110 is made of zirconium (Zr); and the electrolyte solution 130 comprises an acidic solution and arsenous oxide (As₂O₃).
The DC power source 140 provides electrons to the first electrode for a reduction reaction to obtain hydrogen (H₂); and the cathodic reaction formula is as follows:
2H⁺+2e ⁻→H₂ (3)
By using As₂O₃as a catalyst, a hydrogenation efficiency is enhanced; and a great sum of zirconium hydride (ZrH₂) is formed on a surface of the first electrode 110, whose reaction formula is as follows:
Accordingly, the present invention is a hydrogenation electrolysis apparatus 100, which enhances a hydrogenation efficiency to rapidly form ZrH₂on a surface of an electrode.
In this preferred embodiment, a preferred density of As₂O₃is about 0.001M; and, the acidic solution is preferably sulfuric acid (H₂SO₄), whose preferred density is about 0.5M. Yet, the acidic solution can be any strong acidic solution, like nitric acid or hydrochloric acid, whose main function is to provide hydrogen ions (H⁺) for a reduction reaction.
Please refer to FIG. 2A to FIG. 2C, which are a view showing a second preferred embodiment; a view showing a first electrode; and a view showing a second electrode. As shown in the figures, a hydrogenation electrolysis apparatus 200 can further comprise an electrolytic cell 250 to contain the electrolyte solution 130. For further enhancing generation of ZrH₂, a temperature of a electrolyte solution 130 is adjusted to improve a hydrogenation reaction efficiency. In this preferred embodiment, a hydrogenation electrolysis apparatus 200 is similar to that of the previous preferred embodiment 100 (as shown in FIG. 1.) What differs is that the hydrogenation electrolysis apparatus 200 of this preferred embodiment further comprises a heater 260 to heat up an electrolyte solution. Besides, shapes of a first electrode 210, a second electrode 220 and a electrolytic cell 250 of this preferred embodiment are somewhat different from those of the previous preferred embodiment 100, 120, 150.
The electrolyte solution 130 is set in the electrolytic cell 250, and the electrolytic cell 250 is deposed on the heater 260. The heater 260 heats up the electrolyte solution 130 to maintain the electrolyte solution 130 at the best temperature for the reaction. In this preferred embodiment, when the electrolyte solution 130 is at 85° C. and a current density provided by a DC power source is 70 milli-ampere per square centimeter (mA/cm²), the hydrogenation electrolysis apparatus 200 obtains the best ZrH₂generation speed.
In addition, the first electrode 210 and the second electrode 220 can have tube shapes, where the first electrode 210 is located in the second electrode 220. The first electrode 210 and the second electrode 220 can have other shapes, like curved-plate shapes. Furthermore, the second electrode 220 is made of platinum, or other noble meta like gold (Au) or silver (Ag).
Because the electrolyte solution 130 is at a high temperature near a boiling temperature, the electrolyte solution 130 continues hydrogenating and further affects the density of As₂O₃and the sulfuric solution. Please refer to FIG. 2A. To avoid the previous problem, the hydrogenation electrolysis apparatus 200 further comprises a cooler 270; and, the electrolytic cell 250 comprises a main body 252 and a tube 254. Therein, the tube 254 is connected with the main body 252 and is located above the main body 252; and the cooler 270 is surrounded on the tube 254.
The cooler 270 has a water inlet 272 and a water outlet 274, where a cooling liquid 276 is inputted from the water inlet 272 and outputted to the water outlet 274. When the electrolyte solution 130 is evaporated to pass through the tube 254, the cooling liquid 276 takes away vapor energy and the vapor is condensed to be flowed back to the electrolyte solution 130 along the inner wall of the tube 254 to stabilize the density of the As₂O₃and the sulfuric acid solution.
Please refer to FIG. 3, which is a view showing a thickness change of ZrH₂during the deposition. As shown in the figure, a horizontal axis indicates electrification time and a vertical axis indicates the thickness of ZrH₂deposited. When the sulfuric acid solution has a density of 0.5M, the electrolyte solution has a temperature of 85° C. and the current density is 70 mA/cm², a solution is added with 0.001 M of a catalyst of As₂O₃while another solution is added with no catalyst.
Under the same electrification time, the thickness of ZrH₂obtained with As₂ O ₃ 31 as the catalyst is twice as thick as that obtained without As₂ O ₃ 32. Thus, the present invention has a better ZrH₂generating speed, where the set without As₂ O ₃ 32 obtains a thickness of ZrO₂for 34 μm (micrometer) in 15 days and the set with As₂ O ₃ 31 obtains a thickness of ZrO₂for 37 μm in only 3 days. In a word, it saves 80% of time for depositing ZrH₂having the same thickness by using the present invention. Or, in another word, it saves 80% of power waste for a DC power source by using the set with As₂O₃.
To sum up, the present invention is a hydrogenation electrolysis apparatus, having the following advantage:
(1) A deposition of ZrH₂on a Zr tube is greatly enhanced in speed by adding As₂O₃as a catalyst.
(2) On depositing the same thickness of ZrH₂, time used is saved for more than a half and thus power waste is reduced.
The preferred embodiments herein disclosed are not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention.

Claims

1. A hydrogenation electrolysis apparatus, comprising

an electrolyte solution, said electrolyte solution comprising an acidic solution and arsenous oxide (As₂O₃);

a first electrode, said first electrode being located in said electrolyte solution, said first electrode being made of zirconium (Zr);

a second electrode, said second electrode being located in said electrolyte solution; and

a direct current (DC) power source, said DC power source being coupled to said second electrode with an anode of said DC power source, said DC power source being coupled to said first electrode with a cathode of said DC power source.

2. The apparatus according to claim 1,

wherein said As₂O₃has a density of 0.001M.

3. The apparatus according to claim 1,

wherein said acidic solution is a sulfuric acid solution.

4. The apparatus according to claim 3,

wherein said sulfuric acid solution has a density of 0.5M.

5. The apparatus according to claim 1,

wherein said electrolyte solution has a temperature of 85 Celsius degrees (° C.).

6. The apparatus according to claim 1,

wherein said first electrode has a tube-like shape.

7. The apparatus according to claim 1,

wherein said second electrode is made of platinum.

8. The apparatus according to claim 1,

wherein said second electrode has a shape selected from a group consisting of tube-like and curved-plate.

9. The apparatus according to claim 1

wherein said apparatus further comprises an electrolytic cell and a heater;

wherein said electrolytic cell is deposed on said heater; and

wherein said electrolyte solution is located in said electrolytic cell.

10. The apparatus according to claim 9,

wherein said apparatus further comprises a cooler; and

wherein said cooler is rounded on said electrolytic cell.