KR20080050681A - Apparatus for generation and storage of hydrogen using photocatalytic decomposition of water - Google Patents

Abstract

A hydrogen producing and storing apparatus comprising hydrogen production equipment and hydrogen storage equipment is provided, wherein the hydrogen storage equipment is removably constructed to charge fuel cells in a state that the hydrogen storage equipment is separated from the apparatus, and available batteries during the operation of an automobile or general electricity is used as an energy source required in the hydrogen production equipment. As a hydrogen producing and storing apparatus for producing hydrogen by a photodecomposition reaction of water using a photocatalyst, storing the produced hydrogen in the hydrogen storage tank, and supplying the hydrogen as an energy source of fuel cells, the hydrogen producing and storing apparatus comprises: a photodecomposition reactor(3) for decomposing water by a photocatalytic reaction using an ultraviolet lamp(4) as a light source; and a hydrogen storage tank(9) for storing hydrogen produced by the photodecomposition reactor. The hydrogen producing and storing apparatus enables the converted AC to be used as a power source of the ultraviolet lamp used in the photocatalytic reaction, or allows an AC current to be used directly as the power source of the ultraviolet lamp after receiving a DC current from batteries(1) of an automobile in operation and converting the DC current into a 220 V AC through an inverter(2). The hydrogen storage tank contains a porous zeolite as a hydrogen storage material.

Description

Apparatus for Generation and Storage of Hydrogen using Photocatalytic Decomposition of Water}

  1 is a schematic diagram of a hydrogen production and storage device using photolysis of water

  2 shows hydrogen storage curves for zeolite materials

<Explanation of symbols for the main parts of the drawings>

   1: car battery 2: inverter

   3: photolysis reactor 4: ultraviolet lamp

   5: quartz tube 6: reactant

   7: reactant inlet 8: reactant outlet

   9: hydrogen reservoir 10: pressure sensor

  11: gas analyzer 12: AC power (220 V)

  13: hydrogen filling port 14: gas transfer pump

  15: Port 16: On-off valve

Hydrogen energy is well known as an alternative to solve the depletion of energy resources and environmental pollution. The need for global warming, air pollution prevention and energy conservation is expected to be even higher. However, in order to put a hydrogen energy system into practical use, there are many problems to be solved in all fields such as hydrogen production, transportation, storage, conversion, and use. In other words, a variety of technologies such as a production method, a storage method, a transportation method, and a fuel cell capable of mass-producing hydrogen at low prices should be secured.

A fuel cell is a power generation device that converts chemical energy directly into electrical energy through oxidation and reduction reactions in a manner that can efficiently use hydrogen energy. The fuel cell uses hydrogen as an oxidant and emits no pollutants, and is a high-efficiency and eco-friendly technology with higher power generation efficiency than the existing power generation technology.

A fuel cell consists of an anode, a cathode, and an electrolyte between them. Hydrogen introduced into the anode is oxidized by the electrode catalyst and separated into hydrogen ions and electrons. The separated hydrogen ions generate hydrogen through the electrolyte membrane, and the electrons move to the cathode through an external circuit, Reduction reaction generates water, heat and electrical energy.

Micro fuel cell refers to a small fuel cell system with a power output of 100 Wh or less that can be used as a power source for mobile electronic devices such as mobile phones, PDAs, notebook PCs, camcorders, robots, scooters, emergency power systems, remote sensors and micro actuators. In particular, portable mobile communication devices require a larger capacity power supply as the display area increases, and a large data transmission / reception function and a picture and video function are added. As the power consumption of portable devices increases, the need for micro fuel cells also increases.

Micro fuel cells are pollution-free and are highly mobile. Unlike conventional secondary batteries, the charging time is very fast or it is possible to continue using the fuel cartridge without charging. In addition, it is easy to enter the infrastructure because infrastructure is easy to build and the performance and price gap required by the market is smaller than that of large fuel cell systems. Accordingly, the development of fuel cell technology capable of continuously using portable devices for a long time by supplementing and replacing the battery currently used is being actively performed.

Micro fuel cells include Direct Liquid Fuel Cell (DLFC), Direct Methanol Fuel Cell (DMFC), and Solid Oxide Fuel that use methanol, formic acid, and ethanol as direct fuels. Cells (SOFC) and Polymer Electrolyte Membrane Fuel Cell (PEMFC) using hydrogen as a direct fuel.

Micro fuel cells are the first to be commercialized among fuel cells. The successful commercialization of micro fuel cells is expected to have a profound effect on the market of the secondary battery market. Various prototypes have been announced, but the level and price are still insufficient to form a market. In the case of DMFC, the challenge is to increase output, reduce volume, reduce prices, improve durability, and build a methanol supply infrastructure. PEMFC is known to be difficult to build hydrogen supply infrastructure.

DMFC uses PtRu black as a methanol electrode catalyst, and the precious metal loading is 5 mgPt / cm ² , 10 times higher than PEMFC, but has a lower output density than PEMFC. However, PEMFC has better performance than DMFC, but there is a problem that an efficient hydrogen infrastructure capable of supplying hydrogen smoothly must be supported.

As a method of supplying hydrogen to a polymer electrolyte fuel cell, a method of storing with high pressure hydrogen gas, a method of storing with liquid hydrogen, a method of storing with metal hydride, and a method of reforming fossil fuel are well known, but hydrogen storage volume, In consideration of weight, safety, and response characteristics, there are many difficulties in practical use. Therefore, there is an urgent need for the development of hydrogen storage technology suitable for polymer electrolyte fuel cells.

If the infrastructure to easily use hydrogen as fuel is established, the micro fuel cell market expects PEMFC to dominate in an instant. In other words, it is known that building a fuel supply infrastructure is more difficult than the development of fuel cell technology, and if it can be overcome, it is expected that the market of the fuel cell market will change.

The micro-fuel cell industry for IT includes supplying materials and components such as electrodes, catalysts, ion exchange membranes, and separators, manufacturing stacks that combine a plurality of fuel cells composed of these components, and connecting them to portable electronic systems. Can be divided.

The global market for small fuel cells is estimated to have been around since 2002, and NEC, Toshiba, etc. of Japan have launched products using the same. Full-scale mass production is anticipated after 2010. In the initial stage, it is expected to be centered on notebook computers and mobile products after 2012 when technical challenges are solved. To date, no real market has been formed.

The United States estimates that by 2040, hydrogen and fuel cells will replace 11 million barrels of oil demand, the current level of oil imports per day. In the next five years, the company plans to invest $ 1.7 billion in the Hydrogen Fuel Initiative and FreedomCAR Research Partnership.

In November 2003, the United States formed the IPHE (International Partnership for Hydrogen Economy) and began to lead international cooperation in technology development, demonstration, dissemination, standardization, safety, and public relations for the hydrogen economy. Of the energy budgets for 2005, the fuel cell sector increased by 18.9% to $ 75.7 million, and hydrogen technology development increased by 16.3% to $ 95.52 million, increasing investment in hydrogen-related technology development.

In North America and Europe, research on external systems that drive notebooks has become mainstream, and Germany's Smart Fuel Cell is known to have pioneered the initial market to some extent. The German government continues to increase research investment in the German Hydrogen Energy Project to invest 25 million DM in 1997 and 31 million DM in 2000 to develop hydrogen and fuel cell technologies. It also invests 84.8 million DM in the Hysolar project and 30 million DM in the Munich Airport Hydrogen Project. Benz Motors developed and commissioned a hydrogen energy vehicle. It built a hydrogen manufacturing plant using solar energy and is concentrating on developing hydrogen engine and fuel cell system.

Japan has announced plans to invest $ 2.4 billion in research from 1993 to 2020 under the WE-NET project. It is focusing on developing fuel cells for automobiles, homes and buildings for energy self-sufficiency and industrialization of fuel cells. In 2003, a fuel cell vehicle was launched and six hydrogen stations were piloted. It is expected to supply 50,000 fuel cell vehicles by 2010 and 5 million by 2020. In addition, the company has set a goal to supply 201 million kW for residential and building fuel cells by 2010 and 10 million kW by 2020. In Japan, there are many researches on the power supply for notebooks and the power supply for portable devices, and the research on small systems for PDAs is very active.

In addition, France, the United Kingdom, China and Israel are also actively researching hydrogen energy technology.

Korea's hydrogen energy application technology is selected as the core innovation strategy technology of the country and is receiving full support. The Ministry of Commerce, Industry and Energy and the Ministry of Science and Technology have formed a hydrogen energy business team and a frontier business team to support hydrogen energy research.

Research on the development of hydrogen storage materials is also active in Korea. Research on hydrogen storage alloys has been conducted by many researchers for a long time, and researches on applying carbon nanotubes to hydrogen storage have been actively conducted. Recently, Korea's technology level is world-class and the research enthusiasm is very high enough to attract the world's attention by releasing technology that can store large amount of hydrogen in ice particles.

The domestic market for micro fuel cells is estimated to be around 15% of the global market. Commercialization of micro fuel cells requires the construction of fuel infrastructure in addition to technical factors such as price reduction, system miniaturization, and durability.

In the case of laptops, both internal and external types are available, but an external power source with a battery charger concept is expected to be supplied first, and it is expected to enter the market in 2008. The market for high-end equipment such as PDAs, digital cameras, and camcorders is expected to form. Lastly, it is expected to enter the micro fuel cell market for mobile phones, and for this purpose, a lot of research is focused on material and parts production technology and hydrogen fuel infrastructure construction.

In Korea, large companies are developing micro fuel cells using DMFC, but it is known that they have not reached the commercialization stage yet. It may be a next-generation growth business that can replace the secondary battery, but it is insufficient to form a market at the current technology level, and it is difficult to overcome this by the company's own efforts.

The present invention is to provide a hydrogen production and storage device for a fuel cell. Hydrogen production provides a method of obtaining hydrogen by photolyzing water using a photocatalyst. Provided is a hydrogen production and storage device for storing hydrogen prepared from photolysis of water using zeolite materials. The hydrogen production and storage device is detachably configured to charge the fuel cell by separating the hydrogen storage device. The energy source needed for the hydrogen production unit can use idle batteries as an energy source while driving a vehicle to reduce energy costs, and is also configured to use general electricity.

The hydrogen production method provided by the present invention adopts a method by photolysis of water. The reactant 6 obtained by mixing the photocatalyst with water mixed with pure water and photocatalyst or additive as a reactant is placed in the photolysis reactor 3. The photolysis reactor is provided with a reactant inlet 7 and a reactant outlet 8 for supplying a reactant, and a quartz tube 5 for inserting an ultraviolet lamp 4. The lamp uses a 100-1000 W ultraviolet lamp.

 Ultraviolet lamp power is 220V and can use general alternating current. The present invention provides a method of using the vehicle battery (1) to reduce the energy used in the ultraviolet lamp. The car battery is used as a power source when starting and is charged by the car's generator while driving. Therefore, the battery is not used in connection with driving a car while driving. In the present invention, the power of a vehicle in operation is used as a power source of an ultraviolet lamp for photolysis of water. That is, the 12 V DC power generated from the battery 1 of the vehicle is converted into a DC 12 V to 220 V AC using the inverter 2 and used as a power source for the ultraviolet lamp. The power used by the car's battery continues to charge as the car travels, so the energy consumption of UV lamps used for photolysis of water is near zero.

Hydrogen produced in the photolysis reactor of water is sent to the hydrogen reservoir (9) using a gas transfer pump (14). The hydrogen reservoir is filled with a porous zeolite-based hydrogen storage material to adsorb and store hydrogen, and then desorbed to obtain hydrogen. It is configured to supply. The fuel cell may be connected to the hydrogen charging port 13 of the hydrogen reservoir to receive hydrogen.

As shown in FIG. 1, the hydrogen production and storage device provided in the present invention has a size that can be mounted in an automobile, and the photolysis reactor 3 and the hydrogen reservoir 9 for hydrogen production include a connection port 15. It is configured to be detachable by separating or combining. This function is intended to be able to supply hydrogen conveniently to separate the photolysis reactor (3) and the hydrogen reservoir (9) when you want to supply hydrogen.

The composition and composition of the gas produced in the photolysis reactor is configured to send the gas to the gas analyzer 11 for analysis. The gas flow pipe is provided with an on-off valve 16 that can open and close the flow of gas.

Example 1 Hydrogen Production Experiment by Photolysis of Water

Hydrogen production experiment by photolysis reaction of water was performed using the hydrogen production apparatus shown in FIG. Acetaldehyde and methanol were mixed 1: 1 with secondary distilled water and an additive, and 500 ml of the mixed solution added so that the volume ratio to distilled water was 5% was used as a reactant. The photocatalyst suspended 1.0 g of nano titania with 1 wt% Cs in the reaction. The light source used a 450 W high pressure mercury lamp. The composition and concentration of the gas produced by the photolysis reaction were analyzed using the gas chromatograph (11).

Only hydrogen was detected in the gas produced by the photolysis reaction of water. Under the reaction conditions, no oxygen was produced and the hydrogen production rate was 35 mmol / h. After 48 hours, the hydrogen production rate was almost constant, indicating no deactivation of the catalyst. CO was detected when the reaction time was about 5 days. Although the initial concentration of CO was less than 1%, the amount of CO generated slightly increased as the reaction time passed.

Example 2 Determination of Hydrogen Storage of Zeolite Material

In order to use the hydrogen storage material as a material for storing hydrogen by filling the hydrogen storage material, it is necessary to evaluate the hydrogen storage amount of the storage material. In this example, the hydrogen storage of the zeolite was investigated. Zeolites used in the experiments were US-Y (Tosoh Co., Japan) and Mordenite (H-MOR (10), Si / Al = 10, Tosoh Co., Japan). Mordenite (H-MOR (10)) was treated with 6 N sulfuric acid to remove the aluminum in the skeleton to investigate the difference in hydrogen storage according to the Si / Al ratio of Mordenite. Mordenite with aluminum removed is given in parentheses according to the Si / Al ratio.

Hydrogen storage was calculated from PCT (Pressure-Composition Temperature) diagram by applying the volumetric high pressure hydrogen storage measuring method that can calculate the storage from the change in pressure while applying from vacuum to 150 atm.

The amount of hydrogen stored in the zeolite was filled with zeolite in a reaction tube maintained at 30 ° C., and then hydrogen was supplied little by little from the vacuum state to be adsorbed onto the hydrogen storage material, and then pressurized to 100 atm to measure the amount of stored hydrogen. The measured result is shown in FIG. As shown in FIG. 2, Mordenite had more hydrogen storage than US-Y. Mordenite was found to have higher hydrogen storage as the Si / Al ratio increased. The hydrogen storage of H-MOR (10) mordenite was the highest (1.7 wt%) and no hydrogen occlusion occurred above 50 atm.

The development of hydrogen energy technology is set as a core national innovation strategy technology, and the support for technology development is spared, and the concentration of research in this field is increasing. The development of hydrogen production and storage technology, which is an important part of hydrogen energy technology, is believed to be the foundation for the development of hydrogen energy technology in Korea.

The fuel cell industry is a technology-driven industrial field in which industrialization is rapidly progressing due to technology development. However, it is difficult to mass-produce large companies in a short time due to high barriers to entry of technology, and it is expected that it will be difficult to introduce technology from foreign leading companies. Therefore, if technology development is successful, it will be easy to enter the world as well as Korea.

In the recent IT industry where mobility is important, mobile power is very important. Until now, secondary batteries have played this role, but with the advent of micro fuel cells, the competitive landscape of mobile power supplies will inevitably change. In the case of portable fuel cells, the dependence on hydrogen infrastructure is not very high, and if the price and performance are satisfied, the market is expected to expand rapidly.

Hydrogen production by photolysis of water can contribute to the national economy as an eco-friendly technology that can reduce the carbon tax burden under the Kyoto Protocol, unlike other methods of obtaining hydrogen from fossil fuels because pure hydrogen can be obtained from water.

According to the hydrogen production and storage device using photolysis of water provided by the present invention, despite many advantages, it is expected to contribute greatly to the development and proliferation of fuel cells, which have been limited due to the hydrogen fuel infrastructure. It is expected that it will be able to take the technical advantage globally.

Claims (3)

Hydrogen lamp 4 is used as a light source to produce hydrogen using a photocatalytic reaction of water by a photocatalyst, and to store hydrogen in the hydrogen reservoir 9 and supply hydrogen to an energy source of a fuel cell. A device capable of producing and storing hydrogen, comprising a photolysis reactor (3) for decomposing water by a photocatalytic reaction, and a hydrogen reservoir (9) capable of storing hydrogen generated therefrom. Receives a direct current from the battery 1 of the vehicle driving in claim 1 and converts it to 220 V alternating current through the inverter 2 and use it as a power source of the ultraviolet lamp 4 used for the photocatalytic reaction, Device capable of producing and storing hydrogen, characterized by direct use of alternating current A device capable of producing and storing hydrogen, characterized in that the porous zeolite is used as a hydrogen storage material as a storage material used in the hydrogen reservoir (9) in claim 1.

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