Crude oil distillation unit
Feed system: Crude oil needs to be transported through pipelines before entering the distillation tower. On the crude oil feed pipeline, a flow control valve is usually installed to accurately control the feed rate of crude oil. This is because the distillation process requires a stable feed flow rate to ensure the gas-liquid balance and separation effect in the distillation tower. For example, by adjusting the valve opening, the crude oil enters the preheater at a certain flow rate and then enters the distillation tower.
Overhead distillate system: Light fractions such as gasoline and naphtha are produced at the top of the distillation tower. There are pressure control valves on the pipeline of the overhead distillate. These valves can control the pressure at the top of the tower to ensure that the light fraction is separated at a suitable pressure. At the same time, a check valve will be installed to prevent the distillate from flowing back to the distillation tower and affecting the separation effect.
Bottom product system: Heavy fractions such as heavy oil are produced at the bottom of the tower. On the bottom discharge pipeline, there is a temperature control valve to adjust the discharge temperature of the heavy fraction. This is because the physical and chemical properties of heavy fractions will be different at different temperatures, and the appropriate temperature will help with subsequent processing.
Catalytic cracking unit
Raw material transportation and catalyst addition: In the catalytic cracking unit, an electric ball valve will be installed on the crude oil delivery pipeline to control the entry of crude oil. On the catalyst addition pipeline, there is a special metering valve for accurately controlling the amount of catalyst added. Because the amount of catalyst has a crucial impact on the efficiency of the cracking reaction and the quality of the product.
Reaction product separation system: The products after the cracking reaction include various gases, gasoline, diesel, etc. On the product separation pipeline, there are various regulating valves and shut-off valves. The regulating valve is used to control the flow and pressure of the product to achieve the best separation effect. The shut-off valve is used to quickly cut off the pipeline in an emergency or equipment maintenance to prevent the leakage of the reaction product.
Valve application in chemical synthesis process
Ethylene production unit
Raw material cracking system: In the cracking furnace that produces ethylene with naphtha or ethane as raw materials, there is a mass flow controller valve on the raw material delivery pipeline. These valves can accurately control the feed mass flow of raw materials to ensure that the cracking reaction is carried out under the appropriate raw material ratio. There is a high-temperature and high-pressure stop valve on the outlet pipeline of the cracking furnace, which is used to cut off the flow of high-temperature cracking gas during equipment maintenance or emergency.
Product separation and refining system: After ethylene is produced, it needs to be separated and refined from the cracking gas. There are liquid level control valves and pressure control valves on the feed and discharge pipelines of the separation tower. The liquid level control valve is used to adjust the liquid level in the separation tower to ensure the stability of the separation process; the pressure control valve is used to control the pressure in the tower, which is conducive to the separation of ethylene from other impurities.
Polyester synthesis unit
Raw material polymerization system: During the polyester synthesis process, raw materials such as terephthalic acid and ethylene glycol react in the polymerization reactor. On the raw material delivery pipeline, there is a proportional control valve, which is used to deliver raw materials in a certain proportion to ensure the normal progress of the polymerization reaction. On the discharge pipeline of the reactor, there is a gear pump outlet valve, which is used to control the discharge speed of the polymerization product. At the same time, a back pressure valve will be installed to control the pressure in the reactor to ensure the stability of the pressure environment of the polymerization reaction.
Application of valves in the storage and transportation of petrochemical products
Product storage tank area
Storage tank feed pipeline: For storage tanks such as gasoline, diesel, and various chemical raw materials, there are emergency shut-off valves on the feed pipeline. These valves can quickly cut off the feed in case of emergency situations such as fire and leakage to prevent the accident from expanding. At the same time, there will be a level gauge connected to the valve to accurately measure the liquid level in the tank and control the opening of the feed valve according to the liquid level.
Storage tank discharge pipeline: On the storage tank discharge pipeline, there is a flow control valve to control the discharge flow of the product. For example, when the product needs to be loaded or transported to other devices, the opening of the flow control valve is adjusted to make the product flow out at a suitable speed.
Product delivery pipeline
Long-distance delivery pipeline: In the long-distance delivery pipeline of petrochemical products, electric ball valves and electric butterfly valves are used in large quantities. These valves can be operated by remote control systems to conveniently control the flow of products in the pipeline. At the same time, safety valves will be installed to automatically open when the pipeline pressure is too high to release pressure and prevent pipeline rupture.
