The goal of this project is to develop a Virtual Pipeline System Testbed (VPST) for a natural gas transmission system. This test bed will simulate compressor stations, pipelines that connect the compressor stations, supply sources, and the end-user demand markets. System operators and engineers will be able to analyze the impact of system changes on the dynamic deliverability of gas and on the environment.
Kansas State University (KSU) – project management and research product
Manhattan, Kansas 66506
This project entails the development and integration of a pipeline system component computer model. Included in this effort are the enhancement and/or development of computer modules for reciprocating engines, gas turbine engines, centrifugal and reciprocating compressors, pipeline, metering stations, delivery points, and supply points. The component models, and thus the VPST, will be dynamic, giving it the ability to simulate transient gas pipeline operation. Optimization algorithms will be included to assist the VPST user in finding the best design or operating strategy for a given pipeline system.
At the start of the project, Kansas State University developed and analyzed component models for integration into the VPST, including a pipeline node, a compressor station node, a blocking valve node, and a metering station node. Each node has a separate function. For example, the pipeline node will describe the flow of natural gas between points (compressor stations, the gas source, and/or the delivery point). The compressor station node (with reciprocating, gas turbine, and centrifugal gas compressor subnodes) describes how the pressure is increased between the suction and discharge portions of the compressor station and also determines the amount of energy necessary to increase the pressure. The blocking valve subnode is used to isolate the flow of natural gas through the pipeline in the event of pipeline failure, while the metering station subnode is used to monitor the amount of gas that leaves and enters the pipeline system.
The model will allow system operators and engineers to analyze the impact of system changes on the dynamic deliverability of gas and on the environment. The model will provide a user friendly interface to effectively model large sections of the natural gas transmission pipeline infrastructure.
The Compression Unit model has been implemented. This includes the implementation of four combinations of Compression Units:
1) Reciprocating Engine - Reciprocating Compressor
2) Gas Turbine - Centrifugal Compressor
3) Reciprocating Engine - Centrifugal Compressor and
4) Gas Turbine - Reciprocating Compressor.
The properties of the compression units are designed to be read from a central database on the server side, and written back to the server side database under a new name on modification. The database for storing the properties of all the four types of Compression Units was designed and created in Oracle.
The communication loop between the graphical user interface (GUI) and the Parallel Simulator has been completed and tested. Users can now play, replay, stop, pause resume, move forward, move backward, move forward and backward by n steps.
The reciprocating engine model was combined with the reciprocating compressor model. All necessary equations to describe the complete system were documented and implemented. It was realized during documentation that the Cooper GMV4 engine map developed was done so using a constant fuel lower heating value (LHV). However in the VPST system the LHV of the gas in the pipeline that is used to fuel the engines is likely to vary. Hence work is now being done to incorporate the LHV as an input to the engine simulation. Of the various possibilities to do so, one could be to regenerate the maps differently than done earlier, while another possibility could be to modify the fuel flow rate equation to take care of the variability. At the time of this writing, the second option appears more feasible and will be adopted.
Work has started on the simulation of a large pipeline system that runs through Kansas and feeds the Chicago market. This simulation will be conducted with the parallel models and with the sequential models for comparison. Once successful, this particular pipeline will become the test bed to test various combinations of control strategies and engine upgrade concepts.
All tasks have been completed. The final report is listed below under "Additional Information".
Status Assessment [PDF-34KB]
Final Report: Virtual Pipeline System Testbed to Optimize the U.S. Natural Gas Transmission Pipeline System [PDF-1380KB]