Research On The Synchronous Lifting System For Large LNG Storage Tank Dome

With the continuous development of global economy, clean energy plays a significant role in the development and utilization of the energy. Liquefied natural gas(LNG) as the first choice for clean energy, the development of its relevant industries has caught the attention of many countries. The construction of LNG storage tanks plays a vital role in LNG terminal station. A lot of money and manpower are needed to put in it. The dome lift of LNG storage tank is one of the core links in the process of building large LNG storage tank. Gas lift is most used in the dome lift at present. This method has high construction difficulty, low control precision and poor operability, which leads to the poorly stability of the lifting process. Therefore a technical solution is needed to ensure the safety and reliability of the dome lift. The synchronous lifting system for large LNG storage tank dome was studied, based on the comprehensive analysis of the existing technology of the large structures lift.Firstly, the working condition of LNG storage tank dome lift and technology of large structures lift were analyzed in detail. The hydraulic overall scheme of hydraulic system for dome synchronous lifting was researched and designed. Electro-hydraulic proportional speed regulator valve was used as a controller to adjust the flow rate for the system. Electro-hydraulic proportional pressure reducing valve was used to adjust the pressure on the process of lifting. The mathematical model of hydraulic synchronous lifting system for large LNG storage tank dome was established through the analysis of working principle of the lifter and hydraulic system. At the same time, the hydraulic system components were selected and calculated according to the design of lifting scheme. The parameters of the system were determined.Combined with the actual situation and the requirements of hydraulic system, the model of hydraulic system components and hydraulic system were completed by using AMESim software. The simulation analysis was carried out on the main control components and hydraulic system. The accuracy of the model was verified. Based on a new type of pressure and displacement closed loop control method, the synchronous control system design of lifting hydraulic system for large LNG storage tank dome was completed by using the master-slave control strategy. Integrated PID control principle, the control system was modeled by using Simulink software. The co-simulation of hydraulic system was carried out by using the interface of AMESim and Matlab software.The control system was improved by using the fuzzy adaptive PID control. On the basis of conventional PID control technology, a fuzzy adaptive controller was put in the control system. The synchronous movement of the lifting system was achieved through the joint simulation. Real-time online adjustment of parameters on the change conditions was realized through the fuzzy adaptive PID control. The robustness of the system was greatly increased. And the smooth lifting of the dome was realized.In conclusion, research on the synchronous lifting system for large LNG storage tank dome provides an important theoretical basis for the installation of large LNG storage tank dome, which has a great economic significance and important role in engineering practice.