Oil gas total recovery processing system based on diesel oil absorption and condensation and adsorption

Abstract

The invention provides an oil gas total recovery processing system based on diesel oil absorption cooperating with condensation and adsorption, and relates to the technical field of oil gas recovery, the oil gas total recovery processing system comprises a diesel oil absorption tower (T-101), a condensation unit, an adsorption unit and a VOC fan which are connected in sequence; a filler layer is arranged in the diesel oil absorption tower, and countercurrent contact absorption of tail gas and diesel oil is realized through a diesel oil circulation system; the condensing unit comprises a parallel cold box (E-1101AC / BD) and is used for carrying out secondary cooling and liquid removal on the absorbed gas; the adsorption unit deeply removes residual hydrocarbons through an adsorbent; the diesel oil countercurrent absorption is combined with the filler layer design, the hydrocarbon recovery rate is increased by 5% or above, the absorption efficiency is two times that of a traditional condensation process, resource recovery is achieved, condensate and rich absorption diesel oil can be reused for production, raw material waste is reduced, and the production cost is reduced. The comprehensive recovery rate is not less than 98%.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas recovery, and more specifically, particularly relates to an oil and gas full recovery treatment system based on diesel absorption in cooperation with condensation and adsorption. Background Art

[0002] In recent years, with the rapid development of the petrochemical industry, the problem of oil and gas volatilization during the storage, transportation, loading and unloading of oil products has become increasingly prominent. Oil and gas mainly consists of hydrocarbon substances (such as total non-methane hydrocarbons, organic sulfides, etc.). Its direct emission not only causes waste of resources, but also leads to environmental pollution and potential safety hazards. Therefore, the research and application of oil and gas recovery technology have become the focus of attention in the industry.

[0003] At present, the mainstream oil and gas recovery technologies include condensation method, adsorption method and their combined processes. The condensation method liquefies and recovers the hydrocarbon substances in oil and gas through low temperature, but the removal efficiency of low-boiling light hydrocarbons is limited, and the energy consumption is relatively high; the adsorption method uses adsorbents such as activated carbon and molecular sieves to capture hydrocarbons, but the adsorbents are prone to saturation and need to be regenerated frequently, and secondary pollution may occur during the regeneration process. In the prior art, although there are solutions that combine condensation and adsorption, the following problems still exist:

[0004] Incomplete tail gas purification: The content of total non-methane hydrocarbons in the tail gas after treatment by traditional processes is still higher than the environmental protection standard (such as > 1%), which cannot meet the requirements for incineration or direct emission;

[0005] Low resource recovery rate: The hydrocarbon recovery efficiency of condensate and adsorption regeneration gas is insufficient, resulting in oil product loss;

[0006] Poor system stability: Under high humidity or high load conditions, the adsorbent is prone to failure, and the condensation unit is prone to frosting and blockage, affecting continuous operation.

[0007] In addition, the oil and gas dispersion during the loading of light oils (such as gasoline and diesel) is particularly serious. Although some enterprises adopt closed loading technology, the existing recovery devices have insufficient capture ability for light hydrocarbons, resulting in the hydrocarbon concentration exceeding the standard in the environment around the loading platform, posing an explosion risk and violating environmental protection regulations. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides an oil and gas full recovery treatment system based on diesel absorption in cooperation with condensation and adsorption to solve the above problems.

[0009] An oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption, comprising a diesel absorption tower (T-101), a condensation unit, an adsorption unit, and a VOC fan connected in sequence; a packing layer is arranged in the diesel absorption tower, and countercurrent contact absorption of tail gas and diesel is realized through a diesel circulation system; the condensation unit includes parallel cold boxes (E-1101AC / BD) for secondary cooling and liquid removal of the absorbed gas; the adsorption unit deeply removes residual hydrocarbons through an adsorbent; the finally treated gas is pressurized by the VOC fan and then sent to an incineration device to achieve full recovery of hydrocarbon substances.

[0010] Preferably, the diesel circulation system includes an absorbent pump (P-101), a heat exchanger (E-101), and an ethanol cooling medium; the diesel is pressurized by the pump and then undergoes heat exchange with ethanol through the heat exchanger to be cooled to a preset temperature, enters from the upper part of the absorption tower and contacts the tail gas reversely, and the initial boiling point of the rich absorption diesel drops below 85°C. The bottom of the diesel absorption tower (T-101) is connected to a liquid separation tank (D-101) for separating the absorbed liquid phase and gravity refluxing it to the absorption tower; the gas phase enters the condensation unit from the top of the liquid separation tank to achieve efficient gas-liquid two-phase separation. The adsorption unit includes at least two adsorption tanks (B-1101 / 1102), and the adsorbent is activated carbon or molecular sieve; when the adsorption tank is regenerated, 0.6 MPa nitrogen is injected from the top, and the regeneration gas is evacuated by a vacuum pump (PV-1101 / 2) and then mixed with the loading tail gas and re-enters the condensation unit for cyclic treatment.

[0011] Preferably, the cold boxes (E-1101AC / BD) of the condensation unit lower the gas temperature below the dew point through heat exchange, the condensate flows into the condensate tank (T-1101) by gravity, and is transported to the raw material oil tank of the hydrofining unit through a recovery liquid pump (P-1101) to achieve the recovery and utilization of liquid hydrocarbons. The diesel is atmospheric straight-run diesel with an initial boiling point of 170°C. After absorption, the hydrocarbon recovery in the rich absorption diesel increases by more than 5%, and the non-methane total hydrocarbon content in the tail gas drops below 1%. The system also includes a pre-treatment unit, including a dehumidification tank (V-1101) and an induced draft fan (BP-1101); after the loading tail gas is mixed with the regeneration gas of the adsorption tank, it is de-liquefied by the dehumidification tank and pressurized and transported to the diesel absorption tower by the induced draft fan to reduce the initial tail gas humidity and particulate matter load.

[0012] Preferably, the packing layer is structured packing or random packing, the gas-liquid contact area increases by more than 30%, and the absorption efficiency is increased to twice that of the traditional single condensation process. The outlet gas pressure of the VOC fan is 0.2 - 0.5 MPa to ensure stable transportation of the tail gas to the incineration device. The discharged gas after incineration meets the national environmental protection standards. The water molecule content in the tail gas treated by the system is ≤0.5%, and the hydrocarbon recovery rate is ≥98%, realizing zero-pollution emission in the light oil loading link.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Efficient absorption: The countercurrent absorption of diesel combined with the packing layer design improves the hydrocarbon recovery rate by more than 5%, and the absorption efficiency is twice that of the traditional condensation process.

[0015] Deep purification: Through the synergistic effect of condensation and adsorption, the content of non-methane total hydrocarbons in the tail gas ≤ 1%, and the content of water molecules ≤ 0.5%, far exceeding the environmental protection standards.

[0016] Resource recovery: The condensate and rich absorption diesel can be recycled for production, reducing raw material waste, and the comprehensive recovery rate ≥ 98%.

[0017] Energy conservation and environmental protection: The nitrogen regeneration of the adsorption tank and the diesel circulation cooling process reduce energy consumption, and achieve zero pollution emissions after incineration.

[0018] System stability: The multi-stage treatment units cooperate to meet the high-load tail gas treatment requirements, and the pressure control of the VOC fan ensures the transportation stability. Description of the Drawings

[0019] Figure 1 It is a schematic flow diagram of the loading platform system of the present invention. Detailed Embodiments

[0020] The following further describes in detail the embodiments of the present invention in conjunction with the drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0021] Please refer to Figure 1 , the present invention provides an oil and gas full recovery treatment system based on the synergistic condensation and adsorption of diesel absorption, including a diesel absorption tower (T-101), a condensation unit, an adsorption unit, and a VOC fan connected in sequence; a packing layer is arranged in the diesel absorption tower, and the countercurrent contact absorption of the tail gas and diesel is realized through the diesel circulation system; the condensation unit includes parallel cold boxes (E-1101AC / BD) for secondary cooling and liquid removal of the absorbed gas; the adsorption unit deeply removes residual hydrocarbons through the adsorbent; the finally treated gas is pressurized by the VOC fan and sent to the incineration device to achieve the full recovery of hydrocarbon substances.

[0022] The diesel circulation system includes an absorbent pump (P-101), a heat exchanger (E-101), and an ethanol cooling medium. After being pressurized by the pump, diesel is cooled to a preset temperature through heat exchange with ethanol in the heat exchanger, enters from the upper part of the absorption tower, and contacts the tail gas in a countercurrent manner. The initial boiling point of the rich-absorption diesel drops below 85°C. The bottom of the diesel absorption tower (T-101) is connected to a liquid separation tank (D-101) for separating the absorbed liquid phase and gravity refluxing it to the absorption tower. The gas phase enters the condensation unit from the top of the liquid separation tank to achieve efficient gas-liquid separation. The adsorption unit includes at least two adsorption tanks (B-1101 / 1102), and the adsorbent is activated carbon or molecular sieve. When the adsorption tank is regenerated, 0.6 MPa nitrogen is injected from the top, and the regeneration gas is evacuated by a vacuum pump (PV-1101 / 2) and mixed with the loading tail gas, then re-enters the condensation unit for cyclic treatment.

[0023] The cold box (E-1101AC / BD) of the condensation unit cools the gas temperature below the dew point through heat exchange. The condensate flows into the condensate tank (T-1101) by gravity and is transported to the feed oil tank of the hydrofining unit through the recovered liquid pump (P-1101) to achieve the recovery and utilization of liquid hydrocarbons. The diesel is atmospheric straight-run diesel with an initial boiling point of 170°C. After absorption, the hydrocarbon recovery in the rich-absorption diesel increases by more than 5%, and the non-methane total hydrocarbon content in the tail gas drops below 1%. The system also includes a pre-treatment unit, including a dehumidification tank (V-1101) and an induced draft fan (BP-1101). After the loading tail gas is mixed with the regeneration gas of the adsorption tank, it is de-liquefied in the dehumidification tank and pressurized and transported to the diesel absorption tower by the induced draft fan to reduce the initial tail gas humidity and particulate load.

[0024] The packing layer is structured packing or dumped packing, with the gas-liquid contact area increased by more than 30%, and the absorption efficiency increased to 2 times that of the traditional single condensation process. The outlet gas pressure of the VOC fan is 0.2 - 0.5 MPa to ensure the stable transportation of the tail gas to the incineration device. The discharged gas after incineration meets the national environmental protection standards. The water molecule content in the tail gas after the system treatment is ≤0.5%, and the hydrocarbon recovery rate is ≥98%, achieving zero-pollution emission in the light oil loading process.

[0025] Working principle:

[0026] Taking advantage of the structural similarity of hydrocarbon substances in diesel and oil and gas, as well as the characteristics of diesel as a non-polar solvent, the molecules in the oil and gas can dissolve with diesel molecules. Especially for the preliminary absorption of non-methane total hydrocarbons, organic sulfides and other volatile organic gases in the oil and gas, the oil and gas absorbed by diesel can remove the hydrocarbon molecules and water molecules contained in the tail gas to the greatest extent. The traditional light oil vapor recovery only has the functions of condensation and adsorption. The tail gas is first pressurized by a blower and enters the condensation system to cool and remove liquid, and then passes through the adsorption system for purging and regeneration. After this process, the hydrocarbon medium content in the tail gas is still relatively high, and the requirement of completely recovering and sending it to the device for incineration cannot be achieved. In the new process, a diesel absorption function is designed and added. The tail gas first enters the absorption tower. After being circulated and absorbed by diesel to remove liquid, it undergoes secondary liquid removal through gas condensation and is processed by the adsorption unit, meeting the requirements of safety and environmental protection indicators. After being pressurized by the VOC blower, it is sent to the process furnace in the plant area for incineration treatment, realizing the function of airtight recovery and treatment of the oil and gas in the light oil loading link.

[0027] The loading tail gas at the loading platform enters the main pipeline, mixes with the regeneration gas from the adsorption tank, enters the dehumidification tank V-1101 to remove liquid, is pressurized by the induced draft fan BP-1101, and enters the lower part of the newly added diesel absorption tower T-101. A packing layer is set in the tower, and the tail gas contacts the diesel circulated in the tower reversely from bottom to top, absorbing most of the hydrocarbon medium and water molecules in the tail gas.

[0028] The gas phase flows out from the top of the tower, and after removing liquid through the newly added top liquid removal tank D-101 of the absorption tower, the liquid phase flows by gravity to the bottom of the absorption tower, and the gas phase flows out from the top of the tank and enters the cold box E-1101AC / BD through channels. After heat exchange, it enters the bottom of the adsorption tanks B-1101 / 1102, is adsorbed by the adsorbent and flows out from the top of the tank, and is sent to the device for incineration through the VOCS blower.

[0029] The absorbent selected in the diesel absorption tower is atmospheric straight-run diesel. It is pressurized by the absorbent pump P-101 in the absorption tower, cooled by heat exchange with ethanol through E-101, and then enters the absorption tower for circulation from the upper part, contacting the tail gas flowing from bottom to top reversely, and absorbing the hydrocarbon group molecules and water molecules in the tail gas; samples of the rich absorbent oil are taken regularly to analyze the component content and conduct replacement.

[0030] The adsorption tanks are regularly regenerated by nitrogen replacement. Nitrogen at 0.6 Mpa enters from the top of the adsorption tank, and the regeneration gas enters from the bottom of the adsorption tank. After being evacuated by the vacuum pump PV-1101 / 2, it mixes with the tail gas from the loading platform and enters the condensation system through the induced draft fan BP-1101 for further treatment.

[0031] The liquid phase in the cold box flows into the inlet condensate tank T-1101 by gravity, and after being controlled by the valve together with the condensate from the dehumidification tank V-1101, it is pressurized by the recovery liquid pump P-1101 and sent to the raw material oil tank of the hydrofining unit in the 304 tank area.

[0032] Before adding this process flow, the hydrocarbon medium content in the tail gas treated by the oil and gas recovery equipment was still relatively high, and it could not meet the requirement of being fully incorporated into the VOC fan and sent to the process furnace of the unit for incineration, which affected the on-site environment around the loading platform.

[0033] Some light hydrocarbon components in the tail gas are absorbed by the diesel medium. On the one hand, the oil and gas recovery efficiency is improved. According to chemical analysis, the initial boiling point of the rich absorption diesel after absorption is 85°C. Referring to the initial boiling point of fresh diesel at 170°C, the hydrocarbon recovery amount after the tail gas is absorbed by diesel is about 5%. On the other hand, the non-methane total hydrocarbon content in the tail gas after being treated by the new process is <1%, meeting the specified index requirements, achieving full recovery and treatment. The effect of this process is obvious and meets the expected purpose.

[0034] Equipment Tag Equipment Name BP-1101 Induced Draft Fan P-1101 Recovery Liquid Pump P-101 Absorber Pump PV-1101.2 Vacuum Pump E-1101A / C Cold Box E-1101B / D Cold Box E-101 Diesel Oil Cooler T-101 Absorption Tower B-1101 Adsorption Tank B-1102 Adsorption Tank T-1101 Inlet Condensate Tank V-1101 Dehumidification Tank D-101 Absorption Tower Top Liquid Separation Tank

[0035] The embodiments of the present invention are given for purposes of illustration and description, and are not exhaustive or limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. An oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption, characterized in that, It includes a diesel absorption tower (T-101), a condensation unit, an adsorption unit, and a VOC fan connected in sequence; a packing layer is arranged in the diesel absorption tower, and countercurrent contact absorption of tail gas and diesel is realized through a diesel circulation system; the condensation unit includes parallel cold boxes (E-1101AC / BD) for secondary cooling and liquid removal of the absorbed gas; the adsorption unit deeply removes residual hydrocarbons through an adsorbent; the finally treated gas is pressurized by the VOC fan and then sent to an incineration device to realize full recovery of hydrocarbon substances.

2. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as claimed in claim 1, wherein The diesel circulation system includes an absorbent pump (P-101), a heat exchanger (E-101), and an ethanol cooling medium; the diesel is pressurized by the pump and then undergoes heat exchange with ethanol through the heat exchanger to be cooled to a preset temperature, enters from the upper part of the absorption tower, and contacts the tail gas reversely, and the initial boiling point of the rich-absorption diesel drops below 85°C.

3. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as described in claim 1 is characterized in that, The bottom of the diesel absorption tower (T-101) is connected to a liquid removal tank (D-101) for separating the absorbed liquid phase and gravity refluxing it to the absorption tower; the gas phase enters the condensation unit from the top of the liquid removal tank to realize efficient separation of gas and liquid phases.

4. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as claimed in claim 1, wherein, The adsorption unit includes at least two adsorption tanks (B-1101 / 1102), and the adsorbent is activated carbon or molecular sieve; when the adsorption tank is regenerated, 0.6 MPa nitrogen is injected from the top, and the regeneration gas is evacuated by a vacuum pump (PV-1101 / 2) and then mixed with the loading tail gas and re-enters the condensation unit for cyclic treatment.

5. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as claimed in claim 1, wherein The cold boxes (E-1101AC / BD) of the condensation unit lower the gas temperature below the dew point through heat exchange, the condensate flows into the condensate tank (T-1101) by gravity, and is transported to the raw material oil tank of the hydrofining unit through a recovery liquid pump (P-1101) to realize the recovery and utilization of liquid hydrocarbons.

6. The full recovery and treatment system for oil and gas based on diesel absorption combined with condensation and adsorption as described in claim 1, wherein The diesel is atmospheric straight-run diesel with an initial boiling point of 170°C. After absorption, the hydrocarbon recovery in the rich-absorption diesel increases by more than 5%, and the non-methane total hydrocarbon content in the tail gas drops below 1%.

7. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as described in claim 1, characterized in that The system further includes a pre-treatment unit, including a dehumidification tank (V-1101) and an induced draft fan (BP-1101); After the loading tail gas is mixed with the regeneration gas of the adsorption tank, it undergoes liquid removal in the dehumidification tank and is pressurized and transported to the diesel absorption tower by the induced draft fan to reduce the initial tail gas humidity and particulate matter load.

8. The full recovery and treatment system for oil and gas based on diesel absorption combined with condensation and adsorption as claimed in claim 1, wherein The packing layer is structured packing or dumped packing, the gas-liquid contact area increases by more than 30%, and the absorption efficiency is increased to 2 times that of the traditional single condensation process.

9. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as claimed in claim 1, wherein The outlet gas pressure of the VOC fan is 0.2 - 0.5 MPa, ensuring stable transportation of the tail gas to the incineration device, and the discharged gas after incineration meets the national environmental protection standards.

10. The oil and gas full recovery treatment system based on diesel absorption combined with condensation and adsorption as described in claim 1, wherein, The water molecule content in the tail gas treated by the system is ≤0.5%, and the hydrocarbon recovery rate is ≥98%, realizing zero-pollution emission in the light oil loading link.

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