The Simulation of Ultra-High Molecular Weight Polyethylene Cryogenic Pipeline Stress-Strain State

At present the production of polymer materials is developing intensively, new materials, comparable with steels in their strength properties have recently appeared. In this connection, the analysis of polymer materials applied in the pipe industry has been carried out, and the use of ultra-high molecular weight polyethylene (UHMWPE) is proposed as a structural pipeline material, allowing pipes to operate at cryogenic temperatures. The focal point of the article is the consideration of the fracture mechanisms of those materials and the nature of the change in the mechanical properties of UHMWPE under cryogenic temperatures, also taking into account the creep process. The expression for determining the value of the creep modulus depending on the temperature and operating time was obtained. A method is proposed for conducting initial strength estimation. Moreover, the computer model of stress-strain state of an underground cryogenic polymer pipeline for liquefied natural gas transportation is obtained. The results of simulation depict the potential possibility of using of UHMWPE for the cryogenic pipeline construction

The analysis of energy efficiency of LNG filling pipeline from choice of thermal insulation structure

Reduction of technological losses of natural gas during production, transportation and storage is of major energy and environmental importance. Losses of natural gas are the target for active criticism by «green energy» representatives. It is necessary to develop and popularize the new technological solutions aimed at reducing the indirect impact on the environment associated with the production and use of liquefied natural gas, to demonstrate the readiness of specialists of this energy sector to take into account modern social preferences. The article presents the numerical analysis of the energy efficiency for one of the stages of large-scale LNG production, namely, the LNG delivery from a storage tank to a LNG carrier vessel via a cryogenic pipeline. The mathematical model of the thermal enclosure of the pipeline has been considered, and the production cryoproduct losses due to thermal inertia of pipeline materials have been estimated. The performance of the schemes recommended for utilization of LNG vapors has been evaluated

Design and Technology of Winding Curvilinear Pipelines from Sintered Polyimide-Fluoroplastic Film

This article deals with the issues related to designing and manufacturing light and reliable pipelines made of composite materials for missile technology, aircraft and land vehicles running on cryogenic fuel. Multi-layer straight and curvilinear pipelines made by winding polyimide films can significantly reduce the weight and level of bending loads. The article presents the geometry of a typical element of a curvilinear pipeline and the design of the flange of a cryogenic pipeline. A method for connecting the flange shank to the film shell is proposed and the results of testing pipelines made of polyimide-fluoroplastic films are presented. Cryogenic pipelines made of polyimide film PMF-352 have a smaller mass in comparison with metal analogues made of alloy AMg-6 and can be recommended as their replacement in pneumatic hydraulic systems of products operating on cryogenic fuels.

Thermal and Mechanical Coupled Analysis of Marine Composite Cryogenic Pipeline

Marine composite cryogenic pipeline is one of the key equipment for offshore gas explorations, which is mainly used in the transmission of liquefied natural gas. Due to the harsh marine environment and extreme temperature of transmission medium, the marine composite cryogenic pipeline needs to bear both the tensile and bending loads caused by marine environments and the ultra-low temperature load caused by transmission medium. Due to the extremely low temperature of liquefied natural gas, about −163 °C, the structure and the composed material of cryogenic pipelines will be faced greatly challenges. Previous studies have considered mechanical properties or temperature loading separately. In this research, the structural performance of the marine composite cryogenic pipeline under the combined action of mechanical loads and thermo-load is studied with numerical methods. The framework of the coupled mechanical and thermo-analysis for the structure of composite cryogenic pipeline is established. The numerical results show that the temperature distribution has great impacts on the structural responses of the cryogenic pipeline. The coupled mechanical and thermo analysis of the cryogenic pipeline is proved to be necessary. The established method and framework provide a reference for the engineering design and application of the marine composite cryogenic pipeline.