MOSCOW, 6 Jun. Scientists from Tomsk Polytechnic University have proposed using gas hydrates, or artificial combustible ice, for fire extinguishing and localization of fires. According to the researchers, the effectiveness has been proven in more than 200 experiments. The developed combined model for predicting the dissociation and combustion of hydrates is unique and has no analogues, the Ministry of Science and Higher Education of the Russian Federation reported.
The results of the study were published in Thermal Science and Engineering Progress.
Gas hydrates are crystalline compounds that form under certain thermobaric conditions from water and gas. They are also called the frozen fuel of the future, or combustible ice, the scientists explained. One of the areas of their use is the localization and suppression of fires.
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According to the specialists of Tomsk Polytechnic University (TPU), the main task of the fire extinguishing system is to reduce the temperature, displace oxygen from the combustion zone and prevent the access of combustion products. For this, ice, water and inert gas are used.
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«All this is in the composition of the gas hydrate: an inert gas displaces oxygen from the combustion zone, and ice will reduce the temperature in the fire and stop the spread of the combustion front,» said I.N. Butakova Pavel Strizhak.
Scientists conducted more than 200 experiments to localize and suppress the combustion of wood, kerosene, gasoline, diesel fuel, alcohol, crude and refined oil, industrial oils, different grades of coal, waste coal and natural gas methane hydrates.
To do this, they reproduced the ignition conditions in the four most common situations: careless handling of fire, violation of the rules for operating heating equipment, electrical circuits and local fire sources. The experiments were carried out both with indoor and outdoor fires.
The researchers found that in order to block and suppress combustion, an inert gas must be included in the composition of the hydrate. According to them, the most affordable in terms of cost and efficiency are carbon dioxide and freon. The experiments were carried out with gas hydrate in the form of powder and tablet samples.
«We dropped the hydrate on the combustion source from above and made a barrier strip out of it. The results showed the effectiveness of the technology. It should be clarified that these are the early stages of research and work is being carried out with small ignition sources. The main task is to prove the effectiveness of the technology,» added Research Engineer School of Physics of High-Energy Processes at TPU Nikita Shlegel.
Based on experimental data, scientists developed physical and mathematical models for the localization and suppression of combustion of various substances and materials, and also began work on the creation of hydrates, which include surface-active substances.
During dissociation, such a hydrate, in addition to displacing oxygen from the combustion zone and lowering the temperature, makes it possible to create foam on its surface. It is an oxygen blocker and contributes to the localization of combustion and thermal decomposition of the material, the scientists noted.
«The main reason why gas hydrates are still not used to extinguish fires is the lack of data on the burning conditions under which they are effective, and the lack of technologies for transporting, storing and supplying hydrate to the combustion zone. Solving these issues the scientists of our laboratory are busy,” Pavel Strizhak explained.
The project is being implemented as part of the program of the Russian Ministry of Education and Science «Priority 2030», which is one of the measures of state support for universities of the national project «Science and Universities».