Similarly, the use of carbon fuel, compared to thermal power, “Direct Fuel Cell” cleaner, efficient, just because the temperature is too high, it is difficult to use in the car.
Burn rapidly oxidized to carbon dioxide of carbon, using the heat released by heating water with high pressure steam to promote the cutting blade and then to the coil magnetic field lines, the final power to issue – this is the power plant who braved thick smoke billowing, the daily in the event of things, people have become accustomed to it. But by being called “direct carbon fuel cell” technology, carbon dioxide directly into the process in power generation, eliminating the need for more trouble, more efficient, and environmentally friendlier.
Direct carbon fuel cell is “hydrogen fuel cell” next of kin, which is a favorite car company. The use of carbon anodes and high-temperature electrolytes such small power generation equipment, high efficiency can complete the conversion of chemical energy and electrical energy, generated by-products, mostly very pure carbon dioxide. Although the early 19th century, people started trying to create such a fuel cell, but until today, we see some commercial prospects.
On Earth, hydrogen is not considered readily available resources. The carbon is not. Almost anywhere we can find the carbon, coal, oil, chimney of black ash and even agricultural waste and plastic waste have a lot of carbon. Carbon into the direct fuel cell materials, will allow us better access to electricity.
Direct carbon fuel cell is a rapid development since the 1970s. People began to try to use molten carbonate or alkali as the electrolyte, with granular, porous carbon materials as anode, using iron-nickel metal oxides such as the manufacture of fuel cell cathode. In such batteries, carbon and water in the internal reorganization into carbon monoxide and hydrogen, and then reaction with oxygen into carbon dioxide and water. Only electricity and carbon dioxide output, and such a high purity carbon dioxide, completely without purification process, it can be used for industrial production, or direct recovery of like curing. Fuel cells in the process of exploring, people are also looking for more suitable fuel for power generation.
Owen and his team first in the 500 ℃ high temperature nitrogen environment shredded on medium density fiberboard were processed to remove water vapor and other volatile gases. Owen said the low-consuming process can be more intensified solid MDF, lightweight, easy to be sent to the space required. Subsequently, the researchers processed fiberboard made from dry powder, mixed with lithium and potassium carbonate as the electrolyte fuel cell. The temperature is between 500 ℃ to 800 ℃, these mixtures will promote medium density fiberboard for carbon and oxygen into the cell with the combination of electron ionization of carbon dioxide and to generate the required current.
The battery can be made of the current density of 200 mA per square centimeter to the provision of 100 mill watts per square centimeter of power, which means a side length of 10 cm square battery current of 20 amperes in the case of produce 2 volts. This and other types of direct carbon fuel cell is similar to large-scale power plants can be used.
Now, the use of direct carbon fuel cells is also subject to some restrictions. It may not be suitable for electric vehicle – direct carbon fuel cell temperature is higher, using molten hydroxides of the battery temperature is about 400 ℃ to 750 ℃, the battery temperature molten carbonate at 650 ℃ to 800 ℃. Make it more suitable as additional clean power plant modules, or for small independent regional power.
In this fuel cell, the pretreatment of the material is also an important issue. Although it is high purity carbon graphite, its flaky structure does not meet the need and the price too high. It has been found that the activity of anode materials and the degree of disorder depends on the crystal surface area, generally speaking, the more irregular structure than the surface area, activity will be higher. And the use of carbon fiber materials like walnut shell activated carbon from biomass burning has a good performance, but to coal carbonization with a tar bond formed after the high temperature structure, and can meet the needs. If there are too many carbon electrode impurities, so that fuel cells will be quickly deactivated, so how to remove the impurities as much as possible is an important topic pretreatment.
Despite such harsh restrictions, but the tremendous direct carbon fuel cells still make it difficult to give up the advantages. It is environmentally friendly, efficient, and abundant raw materials – Brookhaven National Laboratory calculated that the direct carbon fuel cell-based thermoelectric circulatory system, the thermal efficiency can reach as high 90%; with traditional power plants and hydrogen plants, compared , carbon dioxide emissions can be reduced 77%, there will be considerable cost reduction. Perhaps the direct carbon fuel cell that can help us in today’s increasing lack of fossil fuels and increasingly stringent environmental requirements era, to find more energy. The U.S. magazine recently named in 2010 one of the most promising technology, enough to show that people’s confidence in its bright future.
