The present invention proposes a VOCs safe recovery system and recovery process for heavy oil storage tanks. In order to make the advantages and technical solutions of the present invention clearer and clearer, the present invention will be described in detail below with reference to specific embodiments.
 Such as figure 1 As shown, a VOCs safety recovery system for heavy oil storage tanks of the present invention includes heavy oil storage tank-1, heavy oil storage tank-2, suction cooling liquid window 9 and suction cooling liquid window 10, The suction fan 14 and the process pipeline and pipe fittings. The process pipeline includes a first pipeline, a second pipeline, a third pipeline, and a fourth pipeline. The exhaust port of the heavy oil storage tank 1 is connected to the suction through the first pipeline. The other end of the suction fan is connected to the burner of the heating furnace. The heavy oil volatile gas drawn by the suction fan is passed into the burner of the heating furnace for incineration. The second pipe is connected in the middle of the first pipe, and the second The pipeline is used to send the cooled heavy oil to the underground oil tank. The first pipeline is provided with a first suction inlet valve 11, a suction fan inlet master valve 13, and a suction fan 14 and a heating furnace burner. The outlet check valve 15 of the suction fan and the outlet master valve of the suction fan 16 are arranged in sequence between the outlet check valves and the outlet master valve of the suction fan. Process pipes such as the outlet check valve and the outlet master valve of the suction fan are provided for the convenience of operation. The breathing valve 5, the first suction port muffler 7, the first breathing valve is close to the exhaust port of the heavy oil storage tank 1, and the second pipe is provided with the suction cooling liquid window 1.
 The exhaust port of the heavy oil storage tank 2 is connected to the suction fan 14 through a third pipe, and a fourth pipe is connected to the middle of the third pipe. The fourth pipe is used to send the cooled heavy oil to In the underground oil tank; the second breathing valve 6, the second suction port muffler 8, and the second suction inlet valve 12 are provided on the third pipeline. Among them, the second breathing valve is close to the heavy oil storage tank 2 The exhaust port, the fourth pipe is provided with the second suction cooling liquid window.
 In the above scheme, because the suction fan is directly connected to the atmosphere, and its size is specially designed to ensure the pressure ≮-0.2KPa, it will not cause the heavy oil storage tank to collapse, and a small amount of air entering the gas phase space of the storage tank will The mixed gas of oil and gas will be higher than the upper limit of the explosion limit range, and there is no risk of explosion; because the first suction port muffler 7 and the second suction port muffler 8 are set, the aerodynamic noise can be guaranteed to be ≯60db, so it will not Cause noise pollution.
 In order to prevent safety accidents caused by tempering, the present invention preferably has a flame arrestor 17 between the suction fan and the burner of the heating furnace.
 In order to ensure that the pipeline can be unblocked and purged in time when the pipeline is blocked, the present invention preferably uses a factory air purging device. The factory air purging device is connected to the first pipe, the second pipe, the third pipe, and the fourth pipe. The air purging device is respectively connected to the intersection of the first pipeline, the second pipeline and the intersection of the third and fourth pipelines through the main pipeline. The main pipeline is provided with a factory air master valve 18, a factory wind rotor flowmeter 19, and a factory. The air check valve 20 is provided with a first suction inlet purge valve 21 between the main pipe and the first pipe and the second pipe, and between the main pipe and the third pipe and the fourth pipe. The second suction inlet purge valve 22.
 Furthermore, during normal operation, neither the heavy oil storage tank 1 nor the heavy oil storage tank 2 needs to be supplemented with nitrogen or other media, which achieves the purpose of saving nitrogen consumption. In the present invention, it is preferable that both the heavy oil storage tank 1 and the heavy oil storage tank 2 are connected with a nitrogen supply device, and when the temperature drops suddenly (such as strong wind, rainy weather), the storage tank is filled with oil, etc., the pressure sensor senses the storage tank Pressure changes, that is: when the pressure in heavy oil storage tank one and heavy oil storage tank two is lower than -0.2KPa, the nitrogen sealing valve group one and the nitrogen sealing valve group two and four are automatically opened to replenish nitrogen to the storage tank; if When the pressure continues to drop to -0.295KPa, the breathing valve of the storage tank will automatically open to fill the tank with air to keep the pressure of the storage tank stable.
 The present invention will be further described below in conjunction with specific recycling processes.
 The specific recycling process includes:
 a. Turn on the suction fan. When the suction fan inhales through a suction port that is directly connected to the atmosphere, the first and third pipes connected to them are in a slight negative pressure state. At the same time, the heavy oil storage tank , The pressure in the second heavy oil storage tank is also slightly negative;
 b With the operation of the suction fan, the gas in the heavy oil storage tank 1 and the heavy oil storage tank 2 are pumped out through the first pipe and the third pipe respectively. Among them, the oily mixed gas, the air entering the system, and the air through the suction The air entering from the port enters the suction fan together; the cooled heavy oil enters the underground sewage oil tank through the second pipe and the fourth pipe respectively;
 c Send the remaining volatile oil and gas and air mixed gas from the outlet of the suction fan into the burner of the heating furnace for incineration.
 When the suction fan pumps air through a device directly connected to the atmosphere, the outlet pipe of the breathing valve of the heavy oil storage tank connected with it is in a slightly negative pressure state (-0.2~-0.1KPa), and the heavy oil storage tank The pressure is equal. Therefore, the pressure in the storage tank is also slightly negative. Volatile oil and gas will enter the lower pressure fan inlet and will not enter the atmosphere disorderly, causing environmental pollution.
 The invention does not increase any cost and is safe and reliable when the outlet of the suction fan enters the inlet of the blower or burner of the heating furnace of the device for incineration; the volatile gas of heavy oil is mostly C5-C10 components and contains a certain amount of water vapor. In gaseous state, in order to prevent the recovery of heavy oil to the greatest extent, an oil recovery device is installed in the pipeline between the air extraction device and the air extraction fan. The cooled heavy oil is discharged to the underground sewage oil tank through the window and drain valve designed at the bottom of the pipeline to realize centralized recovery. During normal operation, the storage tank does not need to be supplemented with nitrogen and other media, thus achieving the purpose of saving nitrogen consumption. The factory air purging device is installed to ensure that the pipeline is blocked and used for purge.
 The parts not mentioned in the present invention can be realized by adopting or learning from existing technologies.
 Although the terms such as suction fan, heavy oil storage tank one, heavy oil storage tank two, and first suction port muffler are used more in this article, the possibility of using other terms is not excluded. These terms are used only to describe and explain the essence of the present invention more conveniently; to interpret them as any additional limitation is contrary to the spirit of the present invention.
 It should be further explained that the specific embodiments described in this document are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or additions to the specific embodiments described or use similar alternatives, but they will not deviate from the spirit of the present invention or exceed the definition of the appended claims. Range.