Numerical simulation of temperature drop and residual chlorine effect on water environment in LNG receiving station: a case study in Dongwu port area of Meizhou Bay

During the operation of LNG receiving station, the cold water is discharged into the sea. The temperature drop of the cold water and the residual chlorine have an effect on the temperature field of the water environment and the biological environment of the nearby sea area. In order to understand the diffusion law of cold water discharge in sea water, the effects of LNG cold water discharge on water environment in Dongwu port area of Meizhou Bay were simulated by means of two-dimensional hydrodynamics-water quality numerical coupling model (MIKE21) and nested models. On the basis of reliable model verification, the temperature drop envelope and residual chlorine envelope of LNG cold drainage in winter and summer were calculated,so as to judge the rationality of selecting the project location. The results showed that under the condition of temperature drop greater than 0.5 ℃, the cold drainage influence range of LNG receiving station was 0.202 km², which was about 2.81 km from Meizhou Bay ecosystem reserve and 0.53 km from the nearest breeding area. When the residual chlorine concentration was 0.01 mg/L, the residual chlorine influence range was 0.434 km² and the maximum influence distance was 0.628 km. The temperature drop and residual chlorine of cold water from LNG receiving station had no direct influence on the sensitive targets around the receiving station, and the location of the water outlet was reasonable.