(201a) Dynamic Modeling of the Hybrid LNG Terminal Coupling NGL Recovery and LNG Re-Gasification

With the high demands of shale gas and promising development of LNG terminals, a lot of research has focused towards the process development for effective recovery of C2 and heavier hydrocarbons (NGL). Shale gas requires a large amount of cold energy to cool down and recover the NGL; and the LNG re-gasification process requires a lot of heat energy to evaporate for NGL recovery. Thus, coupling the shale gas NGL recovery process and LNG re-gasification process, for utilizing the cold energy from LNG re-gasification process to assist NGL recovery from shale gas has significant economic benefits on both energy saving and high value product recovery. Wang et al. developed new conceptual design of such coupled process in 2013 [1] and later developed an improved optimal design considering uncertainties in 2014 [2]. In this paper, the virtual validation of this novel conceptual design will be performed via plant-wide dynamic simulations to examine its feasibility and optimality. First of all, a steady-state model of this new process has been developed based on the plant design proposed by Wang et al. with Aspen plus®. The process couples the NGL recovery and LNG re-gasification processes with efficient heat integrations. Next, the dynamic model of the entire process has been developed and tested using Aspen Plus Dynamics® with newly developed control strategies. After that, the flexibility of the dynamic plant model is examined and validated under disturbances of ±25% changes of the shale gas feed flowrate. The energy consumptions associated with different operating conditions will be also investigated. This study successfully demonstrated a novel conceptual design of the hybrid LNG terminal with the integration of both NGL recovery and LNG re-gasification processes.

References

1. Wang, M.; Zhang, J.; Xu, Q. A Novel Conceptual Design by Integrating NGL Recovery and LNG Re-gasification Processes for Maximum Energy Savings. AIChE Journal. 2013, 59, 4673-4685.
2. Wang, M.; Xu, Q. Optimal Design and Operation for Simultaneous Shale Gas NGL Recovery and LNG Re-gasification under Uncertainties. Chemical Engineering Science. 2014, 12, 130-142.