NEW METHODS OF LIFTING SUBSCRIBED OBJECTS AND STRUCTURES WITH THE USING OF LIQUID NITROGEN

Engineering solutions for the use of liquid nitrogen for freezing water in compartments and tanks of sunken objects, as well as engineering structures that were artificially flooded to rise to the surface, are presented. The technology can be partially applied for docking of large ships or fully used for lifting and docking of medium and lowtonnage floating structures. Structural diagrams of the proposed installations, as well as functional and graphic dependences of ice parameters in flooded compartments on the characteristics of the external environment and the capacity of the refrigeration unit are presented. It was found that liquid nitrogen is safer, more efficient and economical compared to similar substances such as hydrazine, air, gunpowder and various fuels. The technologies of using liquid nitrogen using the heat of the environment and gasifying it in the pipeline are considered. To heat liquid nitrogen during its transition to the gaseous state, recommendations for the calculation of a cryogenic gasifier have been developed, which partially uses the internal energy of the transition of water from the liquid to the solid phase state. Computer simulation has proven the possibility of using up to 47% of the heat of the phase conversion of water in the absence of icing of the heat transfer elements of the gasifier. The study developed a computer model for predicting the mass of ice during the direct supply of liquid nitrogen to seawater and found that liquid nitrogen can be fed into the water of the object being blown and if the appropriate technical conditions, the ice on the gasifier elements is not will be created. Liquid nitrogen is an effective, harmless, inert, easy to gasify and one of the cheapest means of creating positive buoyancy for sunken objects. There are various types of installations for the use of liquid nitrogen for ship lifting, depending on the specific tasks. Ice, which is formed on the gas pipeline, does not affect the course of the lifting operation. As an effective means of heating liquid nitrogen in a cryogenic gasifier, seawater can be used, using for this purpose up to 47% of the heat of the phase transition of water from liquid to solid state. Under appropriate conditions, liquid nitrogen can be fed directly into the water of the facility, which is purged by ignoring the freezing of water and the creation of ice plugs at the outlet of the pipeline.