Gas Reliability Analysis Integrated Library (GRAIL)

Abstract

The Gas Reliability Analysis Integrated Library (GRAIL) is a prototype computational tool for solving a class of intra-day model-predictive control problems for a simplified network model of midstream natural gas pipeline systems. The model accurately resolves dynamic gas flows through long pipes using a non-ideal gas equation of state. It can be used to provide optimal intra-day flow schedules as well as spatiotemporal economic values of natural gas while ensuring that pipeline hydraulic limitations, compressor station constraints, operational factors, and pre-existing shipping contracts are satisfied. The inputs to the code are a model of the pipeline system as well as time-series data that specify boundary conditions on the network and time-dependent constraints on the optimal control problem. The outputs are time-series data that provide an approximately optimal solution of flows, pressures, compressor settings, and sensitivities to the objective function.