Abstract:
Objective Vent design is an important part of oil and gas station pipeline system design. To further optimize venting methods and improve the economic efficiency of pipeline design, the research has been conducted on the minimum design temperature, orifice plate diameter, and materials selection for venting systems.
Method Using dynamic simulation software OLGA and HYSYS, this study conducted venting simulations on two natural gas compositions under different actual operating conditions and compared the results. Additionally, the temperature changes after the orifice by altering the orifice diameter was simulated. Subsequently, the calculation results of the two software programs with the results of established orifice diameter calculation formulas under the same pressure relief conditions was compared. Finally, venting system material was selected in accordance with relevant specifications.
Result The average error between the simulation results of OLGA and HYSYS and the measured temperature was 2.57% and 6.04%, respectively. In HYSYS, the minimum temperature after the orifice was determined by selecting the smaller value between the orifice and tailpipe positions, whereas OLGA treated the temperatures at both locations as the same. Simulations in HYSYS with reduced orifice diameter indicated that the temperature after the orifice increased, and the gas Mach number decreased. Under the same pressure relief conditions, the relative errors between the simulated orifice diameters and the calculated results from OLGA and HYSYS were 9.16% and 7.76%, respectively.
Conclusion When determining the minimum temperature for the venting system, the calculation results from OLGA can be used as a reference. When calculating the orifice diameter, the initial orifice diameter from HYSYS can be used. For components of the venting system such as valves, pipes, and flanges under low-temperature conditions, materials should be selected according to material selection standards based on actual operating conditions. The research results can provide a reference for pipe and orifices design in the venting system.
下载: