The Transient Characteristics Of Supercritical Carbon Dioxide Pipelines

The research of CCS?Carbon Capture and Storage?technology in our country is just beginning.We don't have enough knowledge about it.Researching the steady state of supercritical CO₂ transport technology as basis and then studying the transient state such as shutdown,startup and so on.This work agree with the need of CCS technology development and can provide theoretical support for the design and operation of the pipeline project.Firstly,steady state techniques are studied.According to the comparition of calculated values of equations and experimental values,the physical parameters of pure CO₂ can be calculated using PR EOS.Derived formula is more suitable for supercritical CO₂ than recommended.It is provened that NG hermodynamic calculation equation can be used for CO₂ pipeline.The main parameter sensitivity are analysed by cost to get the influence of different parameters on the transportation.Long-distance,low-temperature and high pressure transmission is the most economical way.Heat preservation is not suggested.The transient state of mass flow chang is studied.As a result,the influence of mass flow and mass flow rate on the temperature and pressure,the changing rules of flow parameters and the pressure wave propagation are obtained.With conclusion,the effect of pressure wave propagation to the pipeline must be considered.This article also studied the shutdown and restart transient process.According to the study,we get the the changing rules of flow parameters,water hammer and sudden change phenomenon.We also obtain the feasibility of shutdown at the end point pressure in pipeline,the length of safety shutdown time influenced by mass flow and diameter and the restart changing rules of flow parameters.Giving the following recommendations,trying to control the influence within a certain range by the water hammer,ensuring the pressure does not drop to near the critical point and improving the safety shutdown time by improving the delivery pressure and the amount of mass flow.At last,the transient state of leakage and venting are studied.Both two of the process changing rules of flow parameters is obtain.We also discuss the impact of vent pipe diameter and position.High-pressure transmission methods in engineering practice is better.Preventive work is encouraged.We'd better to set more than one choke valve on the venting pipe.Andthe venting pipe should be set in the middle position of the pipeline section.