Forced ventilation effect by Air-Fin-Cooler in modularized onshore LNG plant

Abstract

Many base load onshore LNG plants use large number of Air-Fin-Coolers normally mounted on the center pipe rack of the LNG process train. Further, the LNG plant modularized approach requires large, complex structures (modules) for supporting the LNG process equipment and for allowing sea and land transportation. This results in additional congestion of the plant and large voids under module-deck, which are confined by large girders. Thus, in case of leaks, the proper ventilation to reduce the accumulation of gas is critical for the safety of the plant.This paper evaluates the Air-Fin-Cooler induced air flow in modularized LNG plants using Computational Fluid Dynamics (CFD) analysis.The results of this evaluation show that the ventilation of the Air-Fin-Cooler induced air flow is influenced by the process train orientation. Further, a moderate increase is observed in specific design conditions or areas, such as shorter separation distances between modules. Based on the results of this evaluation, four design measures are proposed to optimize the use of Air-Fin-Cooler, such as train orientation against prevailing wind direction and use of the grating deck material.