A planned modification to a cokes gas piping involves the installation of a new pipeline to a gas user and the decommissioning of an existing compressor. These changes will integrate two separate systems into one, necessitating an assessment of their impact on system stability. To evaluate this, Dynaflow Research Group conducted a series of transient analyses.
Analysis
The cokes gas network was modeled using BOSfluids software, utilizing isometric drawings, blueprints, and on-site data. This comprehensive model includes representations of gas producers, users, compressors, and the gasholder. Validation of the model against actual measurements and steady-state flow analysis ensured accuracy and reliability. The model was expanded to incorporate the proposed system modifications.
Transient analysis was performed to assess the effects of operational upsets. Initial conditions were set to maximize the impact of these disturbances, resulting in four distinct steady-state models. Key objectives of the transient analysis included determining the adequacy of the current system pressure set point (285 mbarg), identifying maximum and minimum pressures during upset scenarios, evaluating implications for users and producers, suggesting adjustments to set-point pressures or user trip values, and monitoring maximum unbalanced forces.
“The gasholder plays a crucial role in maintaining high-capacity operations of the cokes gas network.”
Results
Based on the analysis findings, several conclusions were drawn:
- No significant short-term issues were observed when the gasholder was operational.
- Manual intervention is necessary when the gasholder is out of service to prevent shutdowns in substantial portions of the system.
- Implementing a strategy for user trip values could enhance system resilience. Consideration may be given to slightly increasing the system set pressure (currently 285 mbarg) to improve user trip selectivity.
- When the gasholder is connected and operational, the compressor response time was found sufficient to maintain pressure within the cokes gas network.
