General

このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

An explanation movie for “Magnesium-based energy cycling” was published on YouTube. It explains advantages of magnesium as “energy-currency” and experiments of solar-pumped-laser and magnesium-engine. Laser is transmited via an optical fiber on the experiment.
Please watch it!

このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

Arab countries are spending their abundant oil moneys to operate numerous sea water desalination plants. They typically use multistage flash evaporation, making use of high temperature steam coming out of thermal power plants to evaporate the sea water to obtain fresh water. Where there are no power generation plants, people are using reverse osmosis process, which filters out salt and other substances when the pressured sea water passes through a membrane (reverse osmosis membrane).
However, the multistage flash evaporation method requires a certain kind of location, and the reverse osmosis method requires a large amount of electric power.
Our group has developed a new sea water desalination technology that does not require either a heat source unlike the multistage flash evaporation method, or a large amount of electrical power unlike the reverse osmosis method. I cannot disclose its mechanisms here because it pertains to our patent application, but I can mention at least that this new technology has a high efficiency even at a small scale desalination plant. This makes it possible to realize a system where we build canals in a desert and place a number of desalination plants along the canal for irrigation.

Read the rest of this entry »

staff on 2009/12/15 11:55
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

Even if the recycling technologies for magnesium is established, where do we obtain magnesium itself? If we are to procure the quantity of magnesium to circulate as energy currency in the current method of mining dolomite, the mining itself would require a huge amount of energy and cost.
Our plan is to obtain magnesium from the sea. There is 1,800 trillion tons of magnesium in the sea in the form of magnesium ion. As everyone knows, you can obtain magnesium chloride (nigari) by condensing the sea water. It follows that we can condense the sea water to obtain magnesium compound, and then we illuminate this with a solar-energy-pumped laser to produce pure magnesium.
Magnesium chloride in the sea water is called hydrous magnesium chloride, which contains chemically bonded water. When it is heated, the water is removed to yield magnesium oxide. The process that follows is essentially the same as the recycling process for magnesium oxide. Acidum hydrochloricum is produced along with magnesium oxide, but it is relatively easy to handle this because it is liquid.

staff on 2009/12/14 23:08
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する
Carbon dioxide gas laser smelts magnesium

Carbon dioxide gas laser smelts magnesium

We have verified that we could obtain 400W-1kW level of power from a solar-energy-pumped laser. Following this result, we went on to conduct another experiment, using a different type of commercial laser, in order to see if we could in fact obtain magnesium. We illuminated magnesium oxide powder with a 1kW carbon dioxide gas laser for 0.2 seconds. This evaporated the surface layer of the powder to produce gas, and we verified that 30% of the gas was magnesium atoms. What is important here is how efficiently we can obtain pure magnesium. The energy reduction efficiency is defined as the ratio of the amount of energy produced by burning magnesium to the amount of laser energy required to produce the magnesium. The larger this efficiency, the better. The efficiency we obtained from the experiment was 45%, which is very close to our target of 50%.

Read the rest of this entry »

このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する A "solar-pumped laser" system in Chitose

If magnesium oxide is given an energy corresponding to 20,000 °C, the bond between its oxygen and magnesium would be broken naturally. It means we can smelt magnesium with no catalyst. Is it possible to inject an energy which is equivalent to 20,000 °C?
You must have played with a magnifying lens to collect the sun light to burn a sheet of paper when you were a child. There is a theoretical upper limit in the temperature obtained by focusing the sun light, which is 6,000 °C. What this means is that no matter how much of the sun light is focused, it is not possible to surpass the temperature of its source, the sun. However, the human wisdom makes it possible to exceed this limit. It is “solar-pumped laser”.

Read the rest of this entry »

staff on 2009/12/14 09:33
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

The amount of magnesium produced world wide in one year is about 600,000 tons. About 70% of this is produced in China, and it is refined using a thermal reduction method. Coal is used as the heat source. It is said that about ten tons of coal is needed to produce one ton of magnesium. This is a very energy consuming process.
It is popularly assumed that we need catalyst such as ferrosilicon in order to refine magnesium. The catalyst is required in order to cut the chemical bond between oxygen and magnesium in magnesium oxide at a relatively low temperature of a thousand and several hundred degrees Celcius. If you factor in energies needed for latent heat to evaporate magnesium and for cutting chemical bond between atoms, the reaction would not occur unless we heat the magnesium oxide up to 20,000 °C. But this also means that as long as the magnesium oxide is given an energy corresponding to 20,000 °C, the bond between its oxygen and magnesium would be broken naturally.

staff on 2009/12/13 22:19
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

We can burn hydrogen which is generated from magnesium and water. The reaction between magnesium and water also generates heat. Through clever use of this heat, the hydrogen generated from the reaction can be burned to produce high-temperature, high-pressure steam. This steam can then be used to rotate turbine to obtain mechanical power, or it can be used for electrical power generation.
In this case, the amount of heat generated from 1kg of magnesium is 25 Mega Joules including the heat generated by burning hydrogen. Coal, on the other hand, generates 30 Mega Joules, which is slightly higher than that from magnesium. However, there is nothing useful remaining after coal is burned; it is not easy to dispose of cinder, and a large amount of carbon dioxide (CO₂) is produced as coal burns.
On the other hand, magnesium oxide, which is produced as magnesium burns (reacts with oxygen), can be recycled to obtain magnesium. The only substances that are produced through burning magnesium are magnesium oxide and water (generated through burning hydrogen) and there is no carbon dioxide emission. There may be a time in the future when magnesium is burned instead of coal at electrical power generation plants.

staff on 2009/12/13 19:22
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する
eVionyx's zinc fuel cell car

eVionyx's zinc fuel cell car

Magnesium can also be used as a fuel for fuel cells.
A lot of laboratories are developing a metal-air battery, such as zinc, aluminium, iron, lithium and magnesium. It is a battery which uses oxidizing properties between metal and oxygen. An ordinary battery needs cathode active and anode active. On the other hand, cathode active of the metal-air battery is oxygen. If metal as anode active can be exchangeable, the metal-air battery becomes a fuel cell.
A passenger fuel cell vehicle requires 6kg of hydrogen in order to run 500km, and the same quantity of energy is produced from about 70kg of magnesium. When it is put in practical use, it is thought that a pack of magnesium cassette will be installed in the power generation compartment of fuel cells. You would replace fuel packs just like you fill up the gas tank of you car with gasoline at a gas station now.
In 2003, a research-oriented venture company for metal fuel cells, eVionyx (Hawthorne, New York State), has developed an experimental car by converting a regular passenger car, and has achieved a continuous run of 600km without replacing its fuel cells. They have also proved that there was no problem in running the vehicle by replacing its fuel cells for over 100 times.
Based on this experimental data, the efficiency of a zinc fuel cell is 500 Watt-Hour per 1kg. If you apply this experimental data to magnesium, the efficiency of a magnesium fuel cell would be 1500 Watt-hour for 1kg of magnesium, which far exceeds that of a lithium ion battery (200Wh).

staff on 2009/12/13 18:14
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

Magnesium is light and strong metal. Its density is a quarter of that of iron, two-thirds of aluminum. It is also a very good conductor of heat.
Another notable property of magnesium is that it is highly reactive. When magnesium meets water, it burns fiercely. Magnesium is no less flammable to hydrogen.
Compared for the same volume, magnesium is heavier than hydrogen. However, hydrogen requires a sturdy tank, and it might leak from the tank in case of an accident. On the other hand, solid magnesium does not catch fire at temperatures below 650 °C , which means it can be stored at room temperature. It can actually be stored for longer than ten years.
Hydrogen, which requires specialized facilities, cannot be stored so easily. If we store energy which a 1million kW power plant generates as hydrogen in 1 atmosphere, we need an enormous tank such as 1km x 1km x 10m. The same amount of energy can be stored as 15m x 15m x 10m of magnesium.

staff on 2009/12/10 00:18
このエントリーをはてなブックマークに追加 Deliciousにブックマーク twitterに投稿する

Diagram of magnesium energy cycle (drawn by YABE Takashi, Nikkei Science)

Diagram of magnesium energy cycle (drawn by YABE Takashi, Nikkei Science)

The current “energy currency” is electricity. The electricity can be distributed through power grids and it can be used for many purposes such as generation of heat, motion and lighting. Hydrogen was generally considered to be a possible energy currency in the future. But what our group is considering as the next-generation energy currency is metal, which is the same as the monetary currency. Namely, it is magnesium, which is lighter than aluminum with white silver glitter.
Seawater contains abundant Magnesium, approximately 1,800 trillion tons. Magnesium can be smelted with “solar-pumped laser” and used for fuel of automobiles and powerplants. Solar-pumped laser regenerates metal Magnesium from generated Magnesium oxide.
A low-cost desalination device with solar-power is used to extract Magnesium from seawater. It will be a promising solution for the global water shortage.

Read the rest of this entry »