GLNG Fuel Gas System Dynamic Simulation
Analyzing system performance, validating control philosophies, and ensuring stable fuel distribution to Gas Turbine Generators across multiple operating scenarios.
Project Overview
The engagement focused on developing a reliable dynamic simulation model of the Fuel Gas System for the GLNG facility. The primary objective was to analyze system performance and fuel gas distribution to the Gas Turbine Generators (GTGs) under multiple operating scenarios.
Our engineering team utilized UniSim Design to replicate plant operating conditions, validate control strategies, and ensure stable operation across varying gas compositions and train interconnection scenarios.
Tools Used
UniSim Design
Dynamic Simulation
Control Philosophy
Logic Validation
Cause & Effect Matrix
Safety Protocol Verification
4-Phase Simulation Methodology
A structured approach to dynamic modeling, ensuring robust system response across all plant operating modes.
Define
Configuring the Fluid Package, setting appropriate thermodynamic models, and reviewing all P&IDs, instrument ranges, and valve datasheets.
Build
Constructing the dynamic model incorporating Knock-Out Drums, Fuel Gas Heaters, and Filter Coalescers with accurate volumes and elevations.
Simulate
Executing 6 dynamic scenarios, evaluating lean vs. rich gas operations and the impact of switching fuel gas sources between Train 1 and Train 2.
Validate
Tuning pressure control loops, verifying stable operation during transitions, and validating overall system redundancy.
Scope of Work
Our deliverables encompass the complete dynamic validation of the system, ensuring the fuel gas network remains stable and responsive to transient operational changes.
Project Compliance
100% OPERATIONAL STABILITY
Dynamic Simulation Model
Fully configured UniSim Design model replicating the as-built P&IDs and physical piping volumes.
Control Loop Validation
Verification of pressure control loops (e.g., PC22077, PC22056) maintaining stable flow to GTGs.
Redundancy Testing
Simulation of 6 operational scenarios, testing lean/rich gas transitions and train interconnectivity.
Equipment Verification
Confirming proper functioning of KO drums and filter-coalescers under varying gas load qualities.
Transient Analysis
Proving that switching fuel supply between Train 1 and Train 2 does not adversely affect system stability.
Commissioning Support
Providing baseline tuning parameters and validation insights for safe plant startup sequences.
Engineering Challenges & Solutions
Variable Feed Compositions
The fuel gas system must accommodate fluctuating compositions ranging from Start of Life to Late Life, as well as distinct “Lean” and “Rich” gas scenarios affecting the combustion stability of the Gas Turbine Generators.
Engineering Solution
Evaluated 6 distinct dynamic scenarios pairing Lean/Rich gas distributions between Train 1 and Train 2. The simulation validated that the Fuel Gas Heaters adequately prevented condensation under all thermodynamic shifts.
Transient Instability Risks
Operating the cross-tie (interconnection) between Train 1 and Train 2 to switch GTG fuel sources introduces rapid pressure transients that could trip the turbines if pressure control loops fail to respond appropriately.
Engineering Solution
Modeled the exact instrument ranges, valve flow characteristics, and set points from the facility’s control philosophy. Proved that the system smoothly manages interconnection valve operations without dropping supply pressure below critical thresholds.
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