Perspectives: Reuse of carbon dioxide as a biofuel

The processing of carbon dioxide, emitted into the atmosphere in epic quantities, is extremely complex, but many scientists believe that this is not only worth the effort, but also necessary. The threat of climate change on the planet is so great that, according to them, it is impossible to cope with the problem without these technologies.

The idea of capturing carbon dioxide produced by coal-fired power plants, etc., for subsequent storage under the ground has already been recognized. Several pilot projects are put into operation or are under implementation.

The proposal to reuse carbon dioxide is less fortunate for the time being: although science has long known that it is possible to obtain fuel by mixing carbon with hydrogen, many people are stopped by the high energy intensity of this process. "We do not have free cheese," says Hans Ziek of the Los Alamos National Laboratory (USA). "Add to this the fact that production is never 100% efficient, so you end up investing more energy than you get." Because of this energy curse, he said, it makes more sense to use fuel from oil. "If nature did it for us for free, why not use it?" The expert concludes.

But oil reserves are drying up. You have to drill deep water, "press" the tar sands and look towards the Arctic. Has the time come for an alternative? Well, for the US, processing carbon dioxide would be a good way to get off the oil needle, but saving the climate is useless, Mr. Zioc stresses, until the process becomes more energy efficient.

Fortunately, there were pioneers in this field. According to them, the technology is imperfect, but it already exists. You can not even collect emissions of power plants or cars, and produce carbon dioxide directly from the air. "They say:" Squeeze it and bury it! " And we say: "No, give it to us, and we will make gasoline out of it!" - are the words of Byron Elton, the executive director of Carbon Sciences from Santa Barbara. "Imagine a future in which water and carbon dioxide are the sources of fuel!" Exclaims Peter Eisenberger, founder of the Earth Institute at Columbia University (USA) and one of the founders of Global Thermostat.

Among the ways to solve the problem is the use of solar energy. Ellen Stechel and her colleagues at the Sandia National Laboratory (USA) are developing a highly efficient chemical heat engine that will operate from the concentrated energy of the luminary. In fact, all energy (including that contained in hydrocarbons) comes from the Sun, so why not again and again try to imitate nature?

Researchers have developed a prototype solar reactor. It is a huge array of mirrors, which focuses sunlight in a powerful beam, directed at the rings of the oxide of a certain metal. The rings rotate and are heated to 1,400 ° C, and then cooled to 1,100 ° C. They are fed carbon dioxide or water. At a high temperature, the rings are given oxygen, and at a relatively low temperature, they are taken back. As a result, carbon monoxide or hydrogen - components of hydrocarbon fuel.

The prototype occupies about 20 m² and serves a reactor the size of a barrel of beer. In order to collect the equivalent of a million barrels of oil per day in the form of sunlight, 121.4 thousand hectares of mirrors (more than Moscow) will be required. We note in parentheses that the world consumes about 86 million barrels of liquid fuels, including biofuels, per day.

The aforementioned Carbon Sciences mixes carbon dioxide with natural gas (or methane as its main component) in the presence of a metal catalyst. It is reported that the latter is made of ordinary metals - nickel and cobalt with the participation of aluminum and magnesium. Well, the transformation of the synthetic gas so obtained into transport fuel is a well-proven technology. The difference between the Carbon Sciences approach is that here it is done on a dry one. The company is already working on the first batch of diesel fuel.

It is important to note that in this process a number of hydrocarbons come from natural gas. Others - for example, the British firm Air Fuel Synthesis - are trying to do the same without methane and using wind power. The goal is a liter of aviation fuel per day (as a demonstration of technology).

Researchers note that one of the most important advantages of such energy is that it will save all the current infrastructure, because it will be the same fuel that we use today. Recall, just the need to invest in the restructuring of infrastructure severely hinders the development of solar and wind power.

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