| Natural gas hydrate,also known as "combustible ice",is known as the new energy in the 21 st century.It is a new clean energy.The carbon content of the global combustible ice is about twice that of the fossil fuel.When mining combustible ice,hydrate is very easy to form.Once formed,hydrate will continue to gather in the pipeline and equipment,forming a freeze block on the pipeline,resulting in blockage of pipeline valves and other equipment.Glycol has a good inhibition effect on hydrate formation,and is often used as hydrate inhibitor,but there are problems such as large glycol loss and energy consumption of glycol regeneration system for a long time.In view of the above problems,it is of great theoretical significance and application value to study the optimization and control method of marine MRU system process parameters for improving the service life of equipment,reducing the dependence on foreign technology,enhancing the technical level and independent innovation ability of combustible ice development in China.The main research contents and achievements are as follows:(1)The existing problems of the traditional MRU process system are described.A new MRU process system with anti scaling and anti-corrosion functions is designed.The process flow of each subsystem is analyzed,and the important equipment required for each system is determined.(2)Using Aspen Plus software,the model of glycol circulation process unit is established,and the processes of MRU system are simulated.The optimal parameters are determined by analyzing the influence of key process parameters on glycol loss and system energy consumption.(3)Using ANSYS CFX software to optimize the internal structure of the negative pressure flash tank,which is an important equipment of MRU system.By analyzing the influence of different structures on the loss of glycol and the energy consumption of the system,the optimization design suggestions for each section are given,which provides the theoretical basis for the design of equipment.(4)The control system of each process of MRU is established to form the information link between the field implementation of automation control and the management,realize the function of remote data collection and monitoring,and achieve the purpose of reducing labor and saving energy.The results show that the optimum flashing temperature of the dehydrogenation process is 55℃,and the optimal flash pressure is 0.13MPa;The mass fractions of divalent cation removers in the de-divalent salt process(i.e.,Na OH and Na2CO3)are 60% and 40%,respectively;The optimal parameters of the regeneration tower in the dehydration regeneration process are that feed temperature is 75℃,column pressure is 0.17 MPa,the number of theoretical boards is 20,and reflux ratio is 0.21;The optimal negative pressure flash temperature of desalination process is 140℃.According to the flow data calculation in this paper,the extended radian of the inlet section of the negative pressure flash tank is 90° and the angle of the transition section is 15°. |
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