Determination of the optimal step of installation between the evaporator pipes and the number of condenser units of the system of temperature stabilization of soils HET

About the authors:

Alexey A. Ishkov, Leading Specialist, Department of Physico-Chemical Methods of Enhancing Oil Recovery, Branch of KogalymNIPIneft LLC, Lukoil-Engineering (Tyumen); IshkovAA@tmn.lukoil.com

Gennady V. Anikin, Cand. Sci. (Phys.-Math.), Leading Researcher, Earth Cryosphere Institute, Tyumen Scientific Centre of the Siberian Branch of the Russian Academy of Sciences; anikin@ikz.ru

Abstract:

Interest in developing the resource base of the Arctic and subarctic regions has recently increased thanks to the efforts of the media, oil corporations and the government, however, it must be understood that during the construction on the soils of these regions, in which ice acts as a cementing material, their natural temperature regime is violated. leading to the melting of the ice phase. It is known that when thawing frozen soil it loses its strength properties, as a result of which the foundations of the structures on which they are built are at risk of deformation and destruction.

To solve this problem, special devices have been developed - seasonally acting cooling devices (SOU), which cool the soil in the cold season and "lock up" in the warm. For this reason, these devices are also called "thermal diodes."

In this work, we consider the system of temperature stabilization of soils HET (horizontal naturally acting tubular system) installed at the base of a vertical steel tank (PBC) filled with hot oil-water mixture. A system is considered, in which ammonia acts as a coolant. In addition, the article carried out calculations of various design solutions of the HET system, expressed in variations of such parameters as the length of the evaporator, the number of condensers, and the installation step between the pipes of the evaporator. The work raises the question of justifying the laying step between the pipes of the HET system evaporator and the number of condenser blocks that will be sufficient for the effective functioning of the system, i.e., to maintain the soil in a frozen state. It is shown that for the effective functioning of the system it is not necessary to use a standard paving step equal to 0.5 m, but it can be increased without the risk of losing the bearing capacity of frozen soil. One of the results of the work is the fact that the system is overdetermined by the temperature of stabilization of soils of the HET type at small distances of the laying step relative to the increased distance, which is expressed in a decrease in the number of working days during a calendar year, all other things being equal.

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