Experts of the Russian Chemical-Technological University. Mendeleev developed a method for producing microporous activated carbons from fruit stones and nut shells. These coals are designed to clean the air from the fumes of gasoline and light oil.
When refilling a tank gasoline, acetone, mineral spirits, and other volatile organic compounds into the atmosphere partially as a vapor. This gives rise to enormous losses. For example, with an average annual consumption of gasoline in Russia 50 million tons of its losses could reach 3.5 million tons. It’s a pity to "throw down the drain" as many valuable substances, not to mention the fact that they pollute the atmosphere.
Part flown away hydrocarbons may again removed from air by adsorption, but expensive adsorbents. Moscow chemists have developed a technology for the production of relatively cheap microporous active carbons from agricultural waste plant: Fruit seeds and shells of various nuts. Besides cheap, the feedstock is valuable its ecological purity compared to synthetic polymers and natural coals.
The adsorbents were obtained by pyrolysis, ie, the thermal decomposition of the absence of air, of the seed plum and walnut shells, peanut and coconut. Raw material was crushed into a particle size of 1-3 mm, were dried to constant weight in a vacuum oven at a temperature of 105 degrees Celsius, and then subjected to pyrolysis. Optimal conditions were selected to obtain a porous solid coal — heating to 800 degrees Celsius in nitrogen for one hour. The pores were produced in small, 0,31-0,35 nm.
Then, the obtained material was performed activation steam. Water molecules can easily penetrate into the depth of coal and facilitate the formation of microvoids. Steaming economical, faster and environmentally safer than chemicals. The researchers picked a steam activation mode that is optimal for the formation of micropores.
Using the thus obtained adsorbent, scientists have developed two techniques of returning hydrocarbon vapor-air mixtures. In one case, the active carbons by heating the absorbed substance. In this case, the pre-adsorbent is purged with nitrogen to a mixture of carbohydrates did not explode. In another method of using vacuum regeneration of activated carbon. Each technology has pros and cons, but both are equally effective.
Air enters the cleaning of tanks which are transported and stored fuel. When restoring the activated carbon produced liquid mixture of gasoline and aromatic hydrocarbons, which in its composition corresponds antidetanatsionnym additives to motor fuel. The researchers propose to return the mixture to the main production and added to gasoline to improve its quality.