Thread Content
Introduction to tank farm system technology 1. Overview of tank farm equipment (1) Device overview Jobs in the tank farm storage and transportation system mainly include: Raw material tank area, pressure tank area, normal pressure tank area, train pallet, automobile pallet and acid-base station ； The main task is to be responsible for the unloading, storage, transportation, loading and other tasks of the raw materials, auxiliary raw materials, intermediate products and products of the entire project. 1) Raw material system The raw material system includes naphtha, hydrogenated tail oil, isobutane, hexene-1, acid and alkali, etc. 2) Under normal production conditions of the intermediate raw material system, the output material from the upstream device directly enters the intermediate raw material tank area. Then it is transported to downstream devices from the intermediate raw material tank area. Intermediate raw materials include ethylene, propylene, cracked C4, benzene, styrene and other products. 3) Refined oil system: Refined oil includes liquefied petroleum gas, benzene, C9, C5, xylene, toluene, butadiene, styrene, raffinate C4 and other products. 4) Loading and unloading system The loading and unloading system is divided into two pallets for cars and trains. It adopts crane tubes with advanced technology, flexible operation and safety. For hydrocarbon loading and unloading, closed crane tubes with oil and gas recovery function are used. ； Acid and alkali adopt immersed crane tube ； Liquefied hydrocarbons use special pressure-tight crane tubes. 5) Equipment selection: A. Spherical tanks are used for hydrocarbon storage, and internal floating roof tanks are used for hydrocarbon storage (of which hydrogenation tail oil, waste alkali and acid-base tanks use vaulted roof tanks). B. Selection of machine and pump. On the premise of meeting the flow rate and head required for production operations, centrifugal pumps, barrel pumps, canned pumps, etc. are mainly used that are efficient, energy-saving, easy to install and maintain. C. Frequently operated valves and valves participating in interlocking control are electric valves or pneumatic valves, and the rest are manual valves. D. Various types of oil storage tanks (except ethylene, propylene, triphenyl, etc.) are equipped with automatic water cutters in the oil tanks to prevent oil from being carried during water cutting operations in the oil tanks. To prevent oil from polluting the atmosphere, atmospheric storage tanks are equipped with nitrogen sealing measures. ； e. In order to facilitate operation and reduce labor intensity for workers, the normal pressure storage tank is equipped with a sampler at the bottom of the tank, and closed sampling is used for toxic media such as benzene and styrene. (2) Design basis: This system satisfies * * Under the premise of industry standards and regulations, we will make full use of the existing land, and on the basis of due consideration for future development, the layout will be based on the principles of conducive to production, convenient management, ensuring safety, and relying on old factories. The selection of equipment and materials should be as domestic as possible, and the design margin should be selected reasonably and appropriately to avoid or reduce unnecessary investment. The design principle of the process is based on our company's management system. Materials between upstream and downstream devices are generally not directly connected and are mainly transferred through the tank area. The design principle of the automatic control chain system is to select a technologically advanced, practical and reliable automatic control system based on the process characteristics and management system of the tank area on the premise of saving investment and being economical and practical. The preliminary design of the main control processes of the tank farm and loading and unloading station is completed by the DCS system. The SIS system is used for emergency situations such as process loss of control. The detection and alarm of flammable and toxic gases are completed by the FGDS system. The operation of the refrigeration compressor is controlled by the MCC system. The shape and structure design of the storage tank are based on the physical and chemical properties of the materials stored in this system. There are vault tanks, internal floating roof tanks, spherical tanks and horizontal tanks. Pressure spherical tanks are equipped with safety valves, and atmospheric pressure tanks are equipped with safety accessories such as breathing valves and flame arresters. In principle, atmospheric pressure oil tanks with high volatility and toxicity are equipped with nitrogen sealing facilities on the top. The storage and transportation of the above liquid media are under automatic control, and the tank area instruments adopt computer centralized monitoring and control. Each storage tank is designed with a liquid level measuring instrument, a high liquid level alarm switch, the main material tank is equipped with a high and high liquid level emergency cut-off feed interlock and a flammable gas alarm in the tank area (eg. Each crane position on the loading pallet is equipped with a flow meter, cut-off valve, quantitative loading instrument, anti-static grounding, and remote control switch to form a loading system. Generally, differential pressure flow meters are mainly used for material measurement. If there are special requirements, the flow meter type should be selected according to the process requirements and material characteristics. Utility consumption needs to be accumulated at the same time. For loading and unloading quantities, a mass flow meter should be used for simultaneous flow accumulation. The material turnover volume of each device and tank area is measured inside the device, and the tank area is not designed with measuring facilities. ； The amount of material entering and exiting the loading and unloading station is measured at the loading and unloading station. Set up one set for the entire storage and transportation area * * public works metering system. The main material inputs are all set with high liquid levels to emergency cut off the feed. Some materials are equipped with emergency stop pumps for low liquid levels. Main materials, such as hydrogenated tail oil, etc., some materials are equipped with emergency stop buttons. The main delivery pump and loading pump are equipped with a minimum flow protection system. Main process parameters such as liquid level, temperature, pressure, flow and other parameters are equipped with remote display and over-limit alarm. All pumps can be stopped remotely, and some pumps can be started remotely. Normal pressure oil products are generally designed to be loaded in a sealed vehicle. As the liquid level continues to rise during loading, the mixed gas of oil and vapor will also merge into the main pipe through the gas phase pipe of the loading and unloading arm, and then pass through the oil and gas recovery device to adsorb harmful gases and discharge them to the atmosphere. In addition, oils with low volatility and toxicity can be loaded into trucks in an open manner, reducing investment costs. For example: C9 loading, etc. There is a waste oil tank each in the normal pressure tank area and the loading dock, which is used to collect the waste oil and take it out via tankers. The oily sewage from the normal pressure (raw material) tank area is sent to the sewage pool of the tank area through underground pipelines. After oil separation, the sewage is sent to the group's sewage treatment plant for treatment, and the dirty oil is loaded into trucks through pumps.