Simulation Of The Process Of High - Sulfur Sulfur - Filled Pipeline In Northeastern China

Pigging technology for oil-gas-water multiphase pipeline plays a crucial role when it comes to safety operation of the gas pipeline system. This paper focuses on the pipelines in Northeast Sichuan Gas Field,which has a relatively wavy terrain. Increasing pressure fluctuation during the process of pigging,a large amount of liquid water, high content of sulfur in the gas itself...these factors contribute greatly to hydrate formation in the pipeline. Based on the prediction of gas hydrate in the pigging process, this paper provides theoretical basis for safety operation of multiphase gas pipeline during pigging. Main work is as follows:(1) The pig by a one-dimensional complex flow problems dealt with in the pipeline movement, based on the analysis pigging process physical model, pigging process can be divided into three parts, namely the establishment of mixed transportation pigging model, the downstream pigging multiphase flow model, pigging model chosen calculation method Minami model multiphase model uses two-fluid model, the coupling of the two models that can describe the flow of the entire pipeline pigging process.(2) Multiphase flow model for solving steady-state and transient process is divided into two processes, the steady-state calculation of the parameters of the time ignored the partial fall, can be solved using the Runge-Kutta method and obtained parameters as the initial transient. Transient process using implicit difference method, under which borrowing Crank-Nicolson implicit finite difference approach. Pigging model needs to be applied Euler Lagrangian method to achieve coupling pigging physical model of transient fluid flow model, you can find the whole model parameters pipe clearing process in accordance with the handling method.(3) This paper uses the C programming language to complete the simulated calculation. The accordingly output parameters are:judge for flow pattern, liquid holdup fluid volume, the speed of pigging operation, pressure drop along the gas pipeline during pigging and so on. OLGA is used for the systematic analyses of relevant factors above in one specific pigging process.(4) Based on Sukhov Formula and J-T Effect, the temperature drop is calculated during the process in which mass content at a section is replaced by liquid holdup to calculate to the specific heat capacity at constant pressure. The temperature drop curve graph is laid out according to the calculation.(5) A prediction model is built to predict the hydrate formation temperature-pressure curve. With the current ambient temperature and pressure drop, whether there will be hydrate formation and where it is located could be known beforehand.Simulation results of the above, such as the pressure drop, the speed of pigging, the time stretch. Verified by OLGA, this paper lays out proof that the model can provide accurate operation speed, time stretch, pressure drop and other parameters during the pigging process, which are essential. Hydrate formation prediction is based on the temperature-pressure drop curve gained from the simulated calculation. Constructive suggestions are given out accordingly in order to provide guidance in the practical multiphase gas transportation.