1 ) System function The mixed refrigerant of this refrigeration unit will be composed of purified natural gas, N2, C2H4 , C3H6 , iC5 H12 . When the system is shut down for maintenance, the refrigerant of the MRC refrigeration unit needs to be discharged. In order to save production costs, it is necessary to recycle these refrigerants. This refrigerant can be returned to the system when needed to minimize refrigerant losses.   2 ) Design parameters Ethylene storage tank volume:       40m 3 Propane storage tank volume:        40m 3 Pentane storage tank volume:        40m 3 Refrigerant recovery tank volume:  50m 3 Tank Type:                                           Horizontal 3 ) Process flow description 1) Refrigerant storage and ratio All refrigerant is supplemented into the refrigerant cycle from the inlet line of the refrigerant compressor inlet balance tank. Ethylene ratio: The liquid ethylene transported by the tanker is unloaded into the ethylene storage tank, and the ethylene from the ethylene storage tank is vaporized by the air-temperature vaporizer, and then enters the refrigerant return pipeline through the flow metering and control valve. Propane ratio: The liquid propane transported by the tanker is unloaded into the propane storage tank through the unloading pump, and the propane from the propane storage tank is dried by the propane dryer, and then enters the refrigerant return pipeline through the flow metering and control valve. Isopentane ratio: the liquid isopentane transported by the tanker is unloaded into the isopentane storage tank, the isopentane from the isopentane storage tank is dried by the isopentane dryer, and then passed through the flow metering and control valve Then enter the refrigerant return pipe. Proportion of purified natural gas: Take a small amount of purified natural gas from the purified gas pipeline before entering the liquefied cold box, and after the pressure is reduced by the control valve, it enters the refrigerant return pipeline through flow measurement. Nitrogen ratio: Take a small amount of nitrogen from the nitrogen pipe network, and after the pressure is reduced by the control valve, it enters the refrigerant return pipe through flow measurement. 2) Refrigerant recovery When it needs to be shut down for maintenance, the liquid from the MRC compressor interstage and final stage separator is discharged into the refrigerant recovery tank through its liquid level control valve. Sichuan Rongteng Automation Equipment Co., Ltd. www. rtgastreat.com E-mail: sales01@rtgastreat.com Phone/whatsapp: +86 138 8076 0589 Address: No. 8, Section 2 of Tengfei Road, Shigao Subdistrict, Tianfu New Area, Meishan city, Sichuan China 620564