XPSIM provides the PIPELINE unit operation to simulate accurately single and multiphase pipeline systems. This unit can be used to design new fluid transport systems as well as to evaluate and analyze existing pipelines.
The PIPELINE unit operation may be applied to:
• natural gas transmission lines
• wet gas/condensate pipelines
• offshore pipelines and risers
• NGL and LPG pipelines
• crude oil pipelines
• utilities transfer lines (steam, water, gas, etc.)
It can handle a wide variety of configurations including inclined and vertical segments, and, used together with other process operations such as:
• valves
• separators
• compressors and pumps
• heaters and coolers
to simulate large pipeline networks.
The PIPELINE unit can treat single phase (vapor or liquid) and multiphase flows with up to 3 phases (a vapor and two immiscible liquids, usually hydrocarbon and water) using enhanced flow correlations. Heat transfer calculations are rigorous and coupled with pressure drop calculations.
The PIPELINE unit operation uses a compositional approach taking into account properly the gas and liquid phases interactions and their PVT (pressure-volume-temperature) behavior.
A large number of literature correlations are available for the calculation of two-phase flow. The PIPELINE unit operation provides a set of models and correlations that apply to the pressure profile calculation of two-phase systems.
The temperature along a pipeline is almost never defined by the user, usually it is calculated either assuming that the pipeline is perfectly insulated and no heat transfer through the walls is taken into account. In this case only the heating/cooling effects related to the Joule-Thomson expansion are considered.
More frequently the user defines the ambient temperature, the pipe and coibent conductivities and the soil conductivities when the pipe is buried. Heat transfer data may be changed for each different pipe segments in order to consider changes in insulation, soil and ambient conductivities, etc.
For the description of pressure-volume-temperature behavior of the phases flowing along the line and, for the calculations of transport properties, the thermodynamic methods available from XPSIM can be selected by the user.
XPSIM can generate property tables for Transient Multiphase Flow Simulators OLGA and LedaFlow
For new systems this operation is used to predict pressure and temperature profiles in order to obtain the correct sizes of pipes and equipments
for existing pipelines this unit operation is used to analyze the throughput capacity and to detect potential bottlenecks.
For a realistic simulation of pipelines and piping systems, the user may define fitting such as valves, bends, elbows, tees, etc.
All flow geometries can be simulated:
• horizontal
• inclined upward
• vertical upward
• inclined downward
• vertical downward
Simulations are performed solving momentum and energy equations across a calculation segments
Two solution algorithms are provided
The first solves separately the momentum and energy balance equations; the second solves the same equations simultaneously.