Tank farm design — Oil storage and transportation processes

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4.1 Oil Storage and Transportation Processes 4.1.1 Overview Oil storage and transportation include the unloading system, storage system, loading system, and control and safety systems for oil. The unloading system is used to transfer the refined oil brought into the warehouse area to storage tanks for storage, through pumps and dip pipes. A storage and monitoring system involves, in accordance with the characteristics of the oil, monitoring, recording, and analyzing daily conditions such as temperature, pressure, and leaks in the storage tanks, in order to ensure their proper operation. The loading system is used to transfer the oil stored in the tank into tank trucks for transportation, via pumps and transfer pipes. Control the security system. 4.1.2 Unloading systems: Based on the type of unloading, they are generally divided into large-diameter hose unloading systems, small-diameter hose unloading systems, and sealed unloading systems. Based on the location where the oil flows out, it can be further divided into upper discharge and lower discharge types. 4.1.3 Storage systems can be divided into above-ground and underground types depending on the location where the oil tanks are placed. Based on the material used for oil tanks, they can be divided into rigid materials and non-rigid materials. Based on the structure of the oil tank, it can be classified into arch roofs, internal floating roofs, etc. 4.1.4 Loading system: Based on the method of loading, it is generally divided into a large flexible hose loading system, a small flexible hose loading system, and a sealed loading system. Based on the location where the oil flows out, it can be further divided into upper-mounted and lower-mounted types. 4.1.5 The control safety system utilizes control systems to provide comprehensive supervision of the oil storage and transportation system, ensuring that the system operates in a safe manner. 4.1.6 The loading and unloading system employs a mechanical pump and a flexible pipe system for sealed oil loading and unloading. 4.2 Storage Principles (1) Determined based on material supply and market forecasts, as well as the volume of material turnover. (2) The type of storage tank is determined based on the properties of the material (such as flash point, explosion limit, and vapor pressure). Gasoline is mainly stored in internal floating roof tanks, and to facilitate interchange between storage tanks, diesel is also stored in internal floating roof tanks. (3) It meets the requirements of **standards regarding environmental protection, safety, and hygiene. (4) The storage tank is equipped with cold water spray facilities to achieve cooling in summer. 4.3 Process flow description: Gasoline and diesel are transported to the unloading area within the warehouse using specialized tank trucks. A sealed unloading method is employed, along with pressurized unloading, to transfer gasoline and diesel into the respective storage tanks for storage. When the fuel delivered by the truck is diesel, the diesel unloading pump is activated, and the pressurized diesel is sent into the diesel delivery pipeline. Depending on the level of fuel in the storage tank, the inlet valve of the tank is opened, and the fuel is delivered to the tank in precise quantities, thus completing the process of unloading the diesel. The diesel loaded into the tank is stored there temporarily awaiting export. When the fuel delivered by the truck is gasoline, the gasoline unloading pump is activated, and the pressurized gasoline is sent into the gasoline delivery pipeline. Depending on the filling level of each tank, the inlet valves for those tanks are opened accordingly, and the fuel is delivered to the tanks in precise quantities, thus completing the gasoline unloading process. The fuel loaded into the tanks is stored there temporarily awaiting export. When transporting diesel, the outlet valve of the diesel storage tank is opened, followed by turning on the diesel pumping pump for loading into vehicles; then the valve of the pump is opened, and the pressurized diesel flows through the delivery pipes, the diesel loading nozzles, and the flow meter before entering the vehicles, thus completing the process of loading diesel. When transporting gasoline, the outlet valve of the gasoline storage tank is opened, followed by turning on the gasoline pump used for filling vehicles. Then the valve of the pump is opened, and the pressurized gasoline flows through the delivery pipes, the filling nozzles, and the flow meter before entering the vehicle, thus completing the process of filling the vehicle with gasoline. This project considers a tank transfer facility in the event of an oil spill from a certain tank. See Figure 3 for details: Piping and instrumentation diagram of the gasoline tank farm. See Figure 4 for details: P&ID of the diesel tank farm pipelines. See Figure 5 for details: Instrumentation flow diagram of the vehicle oil unloading pipeline. See Figure 6 for details: Instrumentation flow diagram of the vehicle fueling pipeline. The design of refined oil storage areas is an engineering task that appears simple but actually involves certain technical complexities. Xie Baomin, a senior engineer at Hualu Engineering Technology Co., Ltd. (formerly the Sixth Design Institute of the Ministry of Chemical Industry), graduated in 1962 from Xi’an Petroleum Institute with a degree in petroleum and natural gas engineering, and possesses over four to five decades of experience in research and design related to new energy sources. And it has its own unique perspectives. It was responsible for the design of Shaanxi Province’s first projects related to dimethyl ether, gas stations, CNG stations, tank farms, methanol gasoline, coalbed methane, and natural gas liquefaction. The dimethyl ether plant designed by Engineer Xie was the first of its kind in China, with an annual production capacity of 300 tons (in 1990). Thanks to years of research and engineering optimization in this field, the investment required for a plant with an annual production capacity of 30,000 tons of dimethyl ether is only over six million. It also possesses extensive design experience and a proven track record in gas stations, CNG stations, tank farms, methanol-blended gasoline, and natural gas liquefaction.