Optimizing the switching method of open rack vaporizer in a natural liquefied gas station

From the operating data of open rack vaporizer (ORV), it is found that the smaller the liquefied natural gas (LNG) flow rate is, the lower the seawater heat required per unit of LNG is. But the lowest seawater heat is not necessarily the lowest seawater flow rate, because ORV has operating constraints such as the minimum seawater film flow rate, the maximum seawater flow rate, and the maximum LNG flow rate. This paper proposes an optimization switching method for multiple ORV vaporizers in an LNG station and gives a calculation method for the optimal switching point. Taking an LNG station with 4 ORVs running in parallel as an example, this paper gives the optimal switching point for the number of ORVs in operation. The optimization method proposed in this paper is generally applicable to intermediate medium vaporizer (IFV).