A heavy oil secondary dry distillation light oil mixed thinning exploitation constant vacuum light oil recycling system

Abstract

This invention provides a system for the extraction and recycling of light oil from heavy oil secondary refining and dilution extraction, comprising: a light oil dilution extraction unit, a heavy oil secondary refining unit, an atmospheric and vacuum distillation unit, a recycling unit, and an environmental protection unit. The light oil dilution extraction unit is connected to the heavy oil secondary refining unit via a gathering and transportation pipeline network. The heavy oil secondary refining unit is connected to the atmospheric and vacuum distillation unit. The atmospheric and vacuum distillation unit is connected to both the light oil dilution extraction unit and the heavy oil secondary refining unit via the recycling unit. The environmental protection unit is connected to each of the three units. This invention offers significant economic benefits, high resource utilization, energy saving and environmental protection, and strong adaptability. It is suitable for high-viscosity heavy oil resources such as those in the Tarim Basin and allows for adjustment of the number of production wells and the scale of the equipment according to production capacity requirements, offering high flexibility.

Description

Technical Field

[0001] This invention belongs to the field of heavy oil extraction and processing technology, specifically relating to a heavy oil secondary dry distillation light oil blending and dilution extraction and light oil recycling system. Background Technology

[0002] Heavy oil, as an important petroleum resource, has high viscosity and is typically... Poor liquidity and numerous limitations of traditional mining methods: Low extraction efficiency: Traditional single-dilution extraction process requires the purchase of a large amount of light oil as a diluent, which not only increases the cost of raw materials, but also has high transportation costs. Especially in remote areas such as the Tarim Basin, the daily output of a single well is only 5-8 tons, which is difficult to meet the demand for large-scale production capacity. Low resource utilization: The extracted heavy oil has not been deeply upgraded, and the heavy components (asphaltite, gum) account for more than 40%. It has low added value when sold directly as commercial oil, and the internal recycling of resources has not been achieved. Energy consumption and environmental protection issues: The thermal efficiency of existing heavy oil dry distillation units is less than 45%, resulting in serious energy waste and high carbon emissions. Traditional processes emit more than 110,000 tons of carbon per year, and the treatment of oily wastewater and solid waste is incomplete, which does not meet the requirements for low-carbon and environmentally friendly development.

[0003] In the current technology, there is no system that deeply integrates "extraction-upgrading-recycling", and it is impossible to solve the problems of low efficiency, resource waste and high energy consumption in heavy oil extraction at the same time. Therefore, there is an urgent need for a high-efficiency, energy-saving and environmentally friendly closed-loop recycling system.

[0004] Based on this, a system for recycling light oil extracted from heavy oil through secondary dry distillation and blending is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a heavy oil secondary dry distillation light oil blending and dilution extraction atmospheric and vacuum light oil recycling system to address the shortcomings of the prior art mentioned above.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a heavy oil secondary dry distillation light oil blending and dilution extraction atmospheric and vacuum light oil recycling system, comprising: Light oil blending extraction unit; Heavy oil secondary dry distillation unit; Atmospheric and vacuum distillation unit; Recycling unit; Environmental protection treatment unit; The light oil blending extraction unit is connected to the heavy oil secondary dry distillation unit through a gathering and transportation pipeline network. The heavy oil secondary dry distillation unit is connected to the atmospheric and vacuum distillation unit. The atmospheric and vacuum distillation unit is connected to the light oil blending extraction unit and the heavy oil secondary dry distillation unit through a recycling unit. The environmental protection treatment unit is connected to the light oil blending and extraction unit, the heavy oil secondary dry distillation unit, and the atmospheric and vacuum distillation unit, respectively.

[0007] As a further explanation of the present invention, the light oil dilution extraction unit includes a horizontal production well, a dilution pump set, and a wellhead mixer; The horizontal production wells are equipped with 200-300 wells, each equipped with a temperature sensor and a pressure sensor, with the temperature controlled at 40-60℃ and the pressure controlled at 8-12MPa; The dilution pump set is a centrifugal oil pump with a flow rate of 50-80 m³ / h. 3 / h, head 100-150m; The wellhead mixer is a static mixer with a mixing efficiency of ≥90% and a mixing ratio of light oil to heavy oil of 1:3-1:5.

[0008] As a further explanation of the present invention, the heavy oil secondary dry distillation unit includes a feed pretreatment device, a secondary dry distillation furnace, a fractionation tower and a waste heat recovery unit. The feed pretreatment device consists of a dehydration tank and a filter for removing impurities. After processing by the feed pretreatment device, the water content of the heavy oil is ≤5% and the impurity removal accuracy is ≤5mm. The secondary distillation furnace is a horizontal rotary furnace with a heating temperature of 380-450℃ and a heating rate of 5-8℃ / min. The fractionation tower separates light oil with a distillation range of 60-180℃, in a yield of 25%-30%. The waste heat recovery unit is a shell-and-tube heat exchanger with a heat recovery rate of ≥80% and a thermal efficiency of ≥55%.

[0009] As a further explanation of the present invention, the atmospheric and vacuum distillation unit includes a desalination tank, an atmospheric pressure tower, a vacuum distillation tower, a cooler, and a light oil storage tank; The desalting tank adopts an electrochemical desalting process, and the salt content of the light oil after desalting is ≤3mg / L; The atmospheric pressure tower has a pressure of 0.12-0.15 MPa and a temperature of 300-320℃. The pressure reducing tower has a pressure of 0.02-0.03 MPa and a temperature of 280-300℃. The cooler cools the light oil to 30-40°C.

[0010] As a further explanation of the present invention, the atmospheric pressure tower separates light oil, accounting for 70%; the vacuum pressure tower separates the remaining light oil, accounting for 30%; and the cooler cools the separated light oil and stores it in a light oil storage tank.

[0011] As a further explanation of the present invention, the recycling unit includes a light oil distribution pump, a flow controller, and a return pipeline; The flow controller distributes light oil at a ratio of 7:3, with 70% being fed back to the light oil blending and extraction unit and 30% used as fuel for the secondary distillation furnace. The return pipeline is made of seamless steel pipe.

[0012] As a further explanation of the present invention, the outer layer of the return pipeline is equipped with a polyurethane insulation layer with a thickness of 50-80mm and an ultrasonic leak detector.

[0013] As a further explanation of the present invention, the environmental protection treatment unit includes an oily wastewater treatment device, a solid waste treatment device, and a CO2 capture device; The oily wastewater treatment device adopts an oil waste recycling process of "air flotation + membrane filtration", with a recycling rate of ≥80%. The solid waste treatment device processes the heavy slag produced by the secondary dry distillation unit into fuel oil; and solidifies the rock cuttings generated during the mining process for use in well site road paving. The CO2 capture device uses the amine method to absorb CO2, with a capture rate of ≥85%.

[0014] As a further explanation of the present invention, the CO2 captured by the CO2 capture device is reinjected into the formation through injection wells for oil displacement, thereby increasing production capacity by 8%-10%.

[0015] Compared with the prior art, the present invention has the following advantages: This invention has significant economic benefits. By circulating light oil internally, there is no need to purchase light oil externally, saving 450 million yuan in raw material costs annually. The daily production of a single well is increased to 15-20 tons. With a production capacity of 3 million tons / year, the annual sales revenue is 13.2 billion yuan. The static investment payback period is only 1.7 years, and the return on investment is 59.2%.

[0016] This invention has a high resource utilization rate. The secondary dry distillation of heavy oil converts heavy components into light oil with a yield of 25%-30%. The remaining heavy residue is used to prepare fuel oil, increasing the comprehensive resource utilization rate to over 95%.

[0017] This invention is energy-saving and environmentally friendly. The waste heat recovery unit improves thermal efficiency to over 55%, saving 320 million yuan in energy costs annually. CO2 capture and reinjection reduce CO2 emissions by 22,000 tons annually. The oily wastewater reuse rate is over 80%, and the solid waste harmless treatment rate is 100%, meeting the requirements for low-carbon and environmental protection.

[0018] This invention is highly adaptable and applicable to high-viscosity heavy oil resources such as the Tarim Basin. The number of production wells and the scale of the equipment can be adjusted according to production capacity requirements, which is highly flexible. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the light oil dilution extraction unit of the present invention; Figure 2 This is a schematic diagram of the heavy oil secondary dry distillation unit of the present invention; Figure 3 This is a schematic diagram of the atmospheric and vacuum distillation unit of the present invention; Figure 4 This is a schematic diagram of the invention's recycling unit; Figure 5 This is a schematic diagram of an invention environmental protection treatment unit.

[0020] Explanation of reference numerals in the attached figures: 11-Horizontal production well; 12-Diluentizing pump set; 13-Wellhead mixer; 14-Gathering and transmission pipeline network; 21-Feed pretreatment device; 22-Secondary distillation furnace; 23-Fracturing tower; 24-Waste heat recovery unit; 31-Desalination tank; 32-Ambient pressure tower; 33-Vacuum pressure tower; 34-Cooler; 35-Light oil storage tank; 41-Light oil distribution pump; 42-Flow controller; 43-Return pipeline; 51-Oil-containing wastewater treatment device; 52-Solid waste treatment device; 53-CO2 capture device. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of this application, not all of them. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] like Figure 1-5 As shown, the present invention provides a technical solution: a system for recycling light oil from heavy oil secondary dry distillation and light oil blending, comprising: a light oil blending unit; a heavy oil secondary dry distillation unit; an atmospheric and vacuum distillation unit; a recycling unit; and an environmental protection unit. The light oil blending extraction unit is connected to the heavy oil secondary dry distillation unit through the gathering and transportation pipeline network 14. The heavy oil secondary dry distillation unit is connected to the atmospheric and vacuum distillation unit. The atmospheric and vacuum distillation unit is connected to the light oil blending extraction unit and the heavy oil secondary dry distillation unit through the recycling unit. The environmental protection treatment unit is connected to the light oil blending and extraction unit, the heavy oil secondary dry distillation unit, and the atmospheric and vacuum distillation unit, respectively.

[0023] In this embodiment, the light oil blending and extraction unit includes a horizontal production well 11, a blending pump set 12, and a wellhead mixer 13; The horizontal production well 11 is equipped with 200-300 wells, each equipped with a temperature sensor and a pressure sensor, with the temperature controlled at 40-60℃ and the pressure controlled at 8-12MPa; The dilution pump set 12 is a centrifugal oil pump with a flow rate of 50-80 m³ / h. 3 / h, head 100-150m; The wellhead mixer 13 is a static mixer with a mixing efficiency of ≥90% and a mixing ratio of light oil to heavy oil of 1:3-1:5.

[0024] In operation, 200 horizontal production wells (11) are installed, with a depth of 3500-4000m, using Φ139.7mm casing; the dilution pump set (12) consists of 3 Φ150mm centrifugal oil pumps, 2 in operation and 1 on standby, with a flow rate of 50m³ / h. 3 / h, head 120m; wellhead mixer 13 adopts a static mixer with a mixing chamber diameter of 80mm and a mixing efficiency of over 90%.

[0025] In this embodiment, the heavy oil secondary dry distillation unit includes a feed pretreatment device 21, a secondary dry distillation furnace 22, a fractionation tower 23, and a waste heat recovery unit 24. The feed pretreatment device 21 consists of a dehydration tank and a filter for removing impurities. After being processed by the feed pretreatment device 21, the water content of the heavy oil is ≤5% and the impurity removal accuracy is ≤5mm. The secondary distillation furnace 22 is a horizontal rotary furnace with a heating temperature of 380-450℃ and a heating rate of 5-8℃ / min; The fractionation tower 23 separates light oil with a distillation range of 60-180℃, with a yield of 25%-30%. The waste heat recovery unit 24 is a shell-and-tube heat exchanger with a heat recovery rate of ≥80% and a thermal efficiency of ≥55%.

[0026] The feed pretreatment unit 21 includes two Φ3000mm dewatering tanks with a processing capacity of 100m³. 3 / h and one Φ2000mm impurity removal filter, with a filtration accuracy of 5mm; The horizontal rotary furnace has a diameter of 3.5m, a length of 20m, a rotation speed of 0.5-1r / min, and is heated by natural gas. Fractionating column 23 has a diameter of 2.8m, a height of 30m, and 30 trays. The shell-and-tube heat exchanger has a heat exchange area of ​​1000㎡ and a heat recovery rate of over 80%.

[0027] In this embodiment, the atmospheric and vacuum treatment unit includes a desalination tank 31, an atmospheric pressure tower 32, a vacuum tower 33, a cooler 34, and a light oil storage tank 35; The desalting tank 31 has a diameter of 2.5m and a height of 8m. It adopts a dual-electrode electrochemical desalting process, and the salt content of the light oil after desalting is ≤3mg / L. The atmospheric pressure tower 32 has a diameter of 3.2m, a height of 35m, 25 trays, a pressure of 0.12-0.15MPa, and a temperature of 300-320℃. The pressure reducing tower 33 has a diameter of 3.5m, a height of 40m, 20 tower plates, a pressure of 0.02-0.03MPa, and a temperature of 280-300℃. The cooler 34 is a plate heat exchanger with a heat exchange area of ​​800㎡. The cooling medium is circulating water, which cools the light oil to 30-40℃.

[0028] The atmospheric pressure tower 32 separates light oil, accounting for 70%; the vacuum tower 33 separates the remaining light oil, accounting for 30%; the cooler cools the separated light oil and stores it in a light oil storage tank.

[0029] In this embodiment, the recycling unit includes a light oil distribution pump 41, a flow controller 42, and a return pipeline 43; Light oil distribution pump 41 uses two Φ125mm gear pumps, one in operation and one on standby, with a flow rate of 30m³ / h. 3 / h, head 80m; The flow controller 42 uses an electromagnetic flow meter with an accuracy of ±0.5%. It distributes light oil at a ratio of 7:3, with 70% being returned to the light oil blending and extraction unit and 30% being used as fuel for the secondary dry distillation furnace 22. The return pipeline 43 is made of Φ219mm seamless steel pipe, with an outer layer of polyurethane insulation with a thickness of 50-80mm and an ultrasonic leak detector. The ultrasonic leak detector has a detection accuracy of 0.1L / min.

[0030] In this embodiment, the environmental protection treatment unit includes an oily wastewater treatment device 51, a solid waste treatment device 52, and a CO2 capture device 53; The oily wastewater treatment device 51 includes two Φ2000mm air flotation units with a processing capacity of 50m³ / h. 3 With one Φ1000mm membrane filtration system per hour, the filtration accuracy is 0.1μm. It adopts the "air flotation + membrane filtration" process to treat oily wastewater generated during mining and processing. The treated water quality meets the "Petroleum Refining Industry Water Pollutant Discharge Standard" (GB 31570-2015) and the reuse rate is over 80%. The solid waste treatment device 52 includes a Φ1500mm heavy slag forming machine with a processing capacity of 10t / h and a Φ2000mm rock cuttings solidifying machine with a processing capacity of 15t / h. It forms heavy slag produced by the secondary dry distillation unit to produce fuel oil and solidifies rock cuttings produced during mining for use in well site road paving. The CO2 capture device 53 uses an amine absorption tower with a diameter of 3.0m and a height of 25m. The absorbent is MDEA solution with a concentration of 30%. It uses the amine method to absorb CO2 with a capture rate of ≥85%.

[0031] The CO2 captured by the CO2 capture device 53 is reinjected into the formation through the injection well for oil displacement, increasing production capacity by 8%-10%.

[0032] In this embodiment, 200 horizontal production wells produce 18 tons per day per well, with an annual capacity of 3.024 million tons, meeting the target of 3 million tons per year. The light oil yield from the secondary dry distillation of heavy oil is 28%, producing 847,000 tons of light fuel oil annually. The annual operating cost is 4.82 billion yuan, the annual sales revenue is 13.25 billion yuan, and the annual net profit is 6.43 billion yuan. The light oil recycling rate is 100%, saving 450 million yuan annually in purchased light oil costs. Waste heat recovery saves 320 million yuan annually in energy costs. The oily wastewater reuse rate is 82%, the solid waste harmless treatment rate is 100%, the CO2 capture rate is 86%, and the annual CO2 emission reduction is 23,000 tons, meeting national environmental protection standards.

[0033] Experimental Example 1: Extra-heavy oil production area of ​​Karamay Oilfield, high-viscosity heavy oil scenario; 1. Heavy oil viscosity: At 50℃, it is classified as extra-heavy oil, and traditional blending extraction requires a higher proportion of light oil. 2. Environmental conditions: Arid terrestrial climate with an average annual temperature of 8-12℃, no risk of low-temperature freezing and blockage, suitable for large-scale well network layout; 3. Production capacity requirements: 3 million tons per year, which needs to be matched with an efficient dry distillation and circulation system to reduce dependence on purchased light oil.

[0034] System Configuration: 1. Light oil blending extraction unit (1) Horizontal production well 11: 250 horizontal production wells with a depth of 4000-4500m. The extra-heavy oil reservoir is buried at a relatively deep depth. The casing specification is Φ177.8mm to enhance the pressure resistance. (2) Diluting pump set 12: 4 Φ180mm centrifugal oil pumps, 3 in operation and 1 on standby, flow rate 60m³ / h 3 / h, higher than the patent baseline value of 50m 3 / h, 150m head, suitable for deep well conveying; (3) Wellhead mixer 13: Static mixer with a mixing chamber diameter of 100mm and built-in baffle to improve mixing efficiency to 95% to meet the needs of high viscosity mixing.

[0035] 2. Heavy oil secondary dry distillation unit (1) Secondary dry distillation furnace 22: Horizontal rotary furnace, diameter 4.0m, length 22m, heating power increased by 20%, adopts "natural gas + heavy slag mixed combustion", heavy slag co-firing ratio 30%, heating temperature 440℃, heating rate 7℃ / min; (2) Fractionating column 23: 3.0m in diameter, 32m in height, 32 trays, for enhanced separation of heavy components; (3) Waste heat recovery unit 24: shell and tube heat exchanger with a heat exchange area of ​​1200㎡, equipped with flue gas waste heat boiler to produce 0.5MPa steam for wellhead heat tracing.

[0036] 3. Environmental protection treatment unit CO2 capture device: amine absorption tower, 3.2m in diameter and 28m in height, the absorbent is a mixed solution of MDEA and piperazine with a concentration of 35%, which improves the low-temperature capture efficiency and the target capture rate is 87%.

[0037] Operation process: 1. Blending extraction: Light oil (distillation range 65-175℃) produced by the atmospheric and vacuum distillation unit is mixed with downhole heavy oil at a ratio of 1:3. After mixing, the viscosity is reduced to... The fluid is pumped to the surface through production wells, and the gathering and transportation pipeline is heated (temperature 50℃) to prevent viscosity from rising again.

[0038] 2. Secondary dry distillation: The heavy oil is pretreated and dehydrated to a water content of 3% and impurities are removed (particle size ≤ 3mm). It is then fed into a dry distillation furnace for pyrolysis at 440℃. The light oil vapor is separated by a fractionation tower with a yield of 29%. The heavy residue is partially blended (30%) and partially used to prepare fuel oil (70%).

[0039] 3. Atmospheric and vacuum distillation: Light oil is desalted to a salt content of 1.8 mg / L. 72% of light oil is separated in atmospheric distillation tower 32 (0.14 MPa, 315℃), and 28% is separated in vacuum distillation tower 33 (0.028 MPa, 295℃). The oil is then cooled to 38℃ and stored.

[0040] 4. Recycling: Light oil is distributed in a 7.5:2.5 ratio, with 75% recycled and diluted, and 25% used as fuel. Due to the reduced fuel demand from the co-firing of heavy slag, the recycling rate is increased to 102%. The results are shown in Table 1 below: Table 1 Experiment Example 2: Offshore heavy oil platform in Bohai Bay, space-constrained scenario 1. Heavy oil viscosity: Medium to high viscosity, limited space on offshore platforms, requiring modular devices; 2. Environmental conditions: High humidity, high salt spray, equipment needs to be corrosion resistant, no large-scale solid waste storage space, volume reduction treatment is required; 3. Production capacity requirement: 2.2 million tons per year, suitable for offshore single-platform well networks, reducing transportation costs (the cost of purchasing light oil offshore is 30% higher).

[0041] System Configuration: 1. Light oil blending extraction unit (1) Horizontal production wells 11:150 horizontal production wells (few wells on offshore platforms), with a depth of 3200-3500m, using subsea wellheads (to prevent salt spray corrosion). (2) Diluent pump set 12: 2 Φ125mm gear pumps (1 in use and 1 on standby), flow rate 40m³ / h 3 / h, reduced in size by 30%, adaptable to platform space; (3) Wellhead mixer 13: Compact static mixer (diameter 60mm), made of 316L stainless steel (salt spray resistant), with a mixing efficiency of 92%.

[0042] 2. Heavy oil secondary dry distillation unit (1) Modular dry distillation system: split horizontal furnace (diameter 3.0m, length 18m, assembled in 3 sections), heating method is electric heating + natural gas (no heavy slag storage space, no co-firing), heating temperature 410℃, heating rate 5.5℃ / min; (2) Fractionation tower 23: Modular packed tower (diameter 2.5m, height 25m), using corrugated packing (specific surface area 250㎡ / m²). 3 It can replace trays to save space without changing the separation efficiency.

[0043] 3. Environmental protection treatment unit (1) Oily wastewater treatment: Integrated "air flotation + ultrafiltration + reverse osmosis" device, with a treatment capacity of 40m³. 3 / h, reuse rate 85%, concentrate meets standards before discharge into the sea (compliant with GB 35500-2017); (2) Solid waste treatment: Rock cuttings are solidified and directly reinjected into the formation (no transportation space), and heavy slag is used to prepare marine fuel oil (not transported out), with a solid waste reduction rate of 100%.

[0044] Operation process: 1. Blending extraction: Light oil and heavy oil are mixed in a ratio of 1:4.5, and the viscosity after mixing is... There is no risk of corrosion in underwater gathering and transportation pipelines (316L stainless steel).

[0045] 2. Secondary dry distillation: Heavy oil is pretreated and dehydrated to a moisture content of 4.5%, and impurities are removed (particle size ≤ 5 mm). It is then pyrolyzed in a dry distillation furnace at 410℃, with a light oil yield of 27%. The heavy residue is used to produce marine fuel (calorific value 42 MJ / kg).

[0046] 3. Atmospheric and vacuum distillation: Light oil is desalted to 2.5 mg / L, with 68% separation achieved in atmospheric distillation column 32 (0.13 MPa, 310℃) and 32% separation achieved in vacuum distillation column 33 (0.025 MPa, 290℃). The oil is then cooled to 35℃ and stored in a 500 m³ / h tank. 3 (Modular).

[0047] 4. Recycling: Light oil is distributed in a 7:3 ratio, and 30% of the fuel is supplied to the dry distillation furnace. Since there is no heavy slag co-firing, the fuel consumption is consistent with that in this embodiment, and the recycling rate is 100%.

[0048] The results are shown in Table 2 below: Table 2 Experimental Example 3: Low-temperature production area in the Junggar Basin, severe cold environment scenario. 1. Heavy oil viscosity: In winter, when the temperature drops to -25℃, the viscosity easily rises back to [a certain value]. above; 2. Environmental conditions: large temperature difference between day and night (-25℃~15℃), requiring protection against freezing and blockage, and high demand for waste heat (high heat tracing consumption in winter). 3. Production capacity requirements: Annual production capacity of 2.8 million tons, requiring improved waste heat utilization rate and reduced energy consumption in winter.

[0049] System Configuration: 1. Light oil blending extraction unit (1) 11:220 horizontal production wells, each with an electric heat tracing device (5kW / well) installed at the wellhead, and the gathering and transmission pipeline adopts "polyurethane insulation + rock wool outer protection"; (2) Diluting pump set 12: 3 Φ150mm centrifugal oil pumps (2 in operation and 1 on standby), with low temperature start-up device (can be started at -30℃), flow rate 55m³ / h 3 / h, head 130m.

[0050] 2. Heavy oil secondary dry distillation unit (1) Secondary distillation furnace 22: Horizontal rotary furnace (diameter 3.8m, length 21m), furnace body insulation layer thickness 150mm, heating temperature 430℃, heating rate 7℃ / min; (2) Waste heat recovery unit 24: a double shell-and-tube heat exchanger (heat exchange area 1300㎡), connected in series with the wellhead heat tracing system, the waste heat utilization efficiency is increased to 85%, and the tail gas temperature is reduced to 120℃.

[0051] 3. Recycling Unit Return pipeline 43: Φ273mm seamless steel pipe (thickened to resist freezing and cracking), 80mm polyurethane insulation layer + electric heat tracing (power 20W / m), leak detector with low temperature adaptation function (normal operation at -30℃).

[0052] Operation process: 1. Blending extraction: Light oil and heavy oil are mixed in a ratio of 1:3.5, with the mixing temperature controlled at 55℃. After mixing, the viscosity is reduced to... The temperature of the gathering and transmission pipeline network is maintained at 50°C, and there is no freezing or blockage.

[0053] 2. Secondary dry distillation: Heavy oil is pretreated and dehydrated to a water content of 3.5%, and impurities are removed (particle size ≤ 4 mm). The oil is then pyrolyzed in a dry distillation furnace at 430℃, resulting in a light oil yield of 28.5%. The residual heat is preferentially supplied to the wellhead for heat tracing (meeting 80% of the heat tracing needs in winter).

[0054] 3. Atmospheric and vacuum distillation: Light oil is desalted to 2.2 mg / L, 71% is separated in atmospheric distillation tower 32 (0.135 MPa, 312℃), and 29% is separated in vacuum distillation tower 33 (0.026 MPa, 292℃). It is then cooled to 40℃ for storage to prevent low-temperature adhesion to the tank walls.

[0055] 4. Recycling: Light oil is distributed in an 8:2 ratio (80% recycled, 20% fuel). Due to the replacement of electric heating with waste heat, fuel consumption is reduced by 10%, and the recycling rate is 105% (including waste heat as an alternative energy source).

[0056] The results are shown in Table 3 below: Table 3 The comprehensive comparison of the three experimental cases is shown in Table 4 below: Table 4 In summary, the system in this embodiment can be fine-tuned through equipment parameters, and the dilution ratio, temperature, insulation, and modular adaptation can be made to heavy oil development scenarios with different viscosity, environmental, and space requirements. It can achieve the goal of "no external purchase of light oil, high production capacity, and low energy consumption", and has universality and practicality.

[0057] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0058] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0059] The directional terms "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," or "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0060] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0061] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for recycling light oil extracted from heavy oil through secondary dry distillation and blending, characterized in that, include: Light oil blending extraction unit; Heavy oil secondary dry distillation unit; Atmospheric and vacuum distillation unit; Recycling unit; Environmental protection treatment unit; The light oil blending extraction unit is connected to the heavy oil secondary dry distillation unit through the gathering and transportation pipeline network (14), the heavy oil secondary dry distillation unit is connected to the atmospheric and vacuum distillation unit, and the atmospheric and vacuum distillation unit is connected to the light oil blending extraction unit and the heavy oil secondary dry distillation unit through the recycling unit. The environmental protection treatment unit is connected to the light oil blending and extraction unit, the heavy oil secondary dry distillation unit, and the atmospheric and vacuum distillation unit, respectively.

2. The heavy oil secondary dry distillation light oil blending and dilution extraction light oil recycling system according to claim 1, characterized in that, The light oil blending and extraction unit includes a horizontal production well (11), a blending pump set (12), and a wellhead mixer (13). The horizontal production wells (11) are equipped with 200-300 wells, each equipped with a temperature sensor and a pressure sensor. The temperature is controlled at 40-60℃ and the pressure is controlled at 8-12MPa. The dilution pump set (12) is a centrifugal oil pump with a flow rate of 50-80 m³ / h. 3 / h, head 100-150m; The wellhead mixer (13) is a static mixer with a mixing efficiency of ≥90% and a mixing ratio of light oil to heavy oil of 1:3-1:

5.

3. The heavy oil secondary dry distillation light oil blending and dilution extraction light oil recycling system according to claim 2, characterized in that, The heavy oil secondary dry distillation unit includes a feed pretreatment device (21), a secondary dry distillation furnace (22), a fractionation tower (23), and a waste heat recovery unit (24). The feed pretreatment device (21) consists of a dehydration tank and a filter for removing impurities. After being processed by the feed pretreatment device (21), the water content of the heavy oil is ≤5% and the impurity removal accuracy is ≤5mm. The secondary distillation furnace (22) is a horizontal rotary furnace with a heating temperature of 380-450℃ and a heating rate of 5-8℃ / min; The fractionation tower (23) separates light oil with a distillation range of 60-180℃, with a yield of 25%-30%; The waste heat recovery unit (24) is a shell-and-tube heat exchanger with a heat recovery rate of ≥80% and a thermal efficiency of ≥55%.

4. The heavy oil secondary dry distillation light oil blending and dilution extraction light oil recycling system according to claim 3, characterized in that, The atmospheric and vacuum treatment unit includes a desalination tank (31), an atmospheric tower (32), a vacuum tower (33), a cooler (34), and a light oil storage tank (35). The desalting tank (31) adopts an electrochemical desalting process, and the salt content of the light oil after desalting is ≤3mg / L; The atmospheric pressure tower (32) has a pressure of 0.12-0.15 MPa and a temperature of 300-320℃; The pressure reducing tower (33) has a pressure of 0.02-0.03 MPa and a temperature of 280-300℃; The cooler (34) cools the light oil to 30-40°C.

5. A system for recycling light oil extracted from heavy oil through secondary dry distillation and blending, as described in claim 4, is characterized in that... The atmospheric pressure tower (32) separates light oil, accounting for 70%; the vacuum tower (33) separates the remaining light oil, accounting for 30%; the cooler (34) cools the separated light oil and stores it in a light oil storage tank.

6. A system for recycling light oil extracted from heavy oil through secondary dry distillation and blending, as described in claim 5, is characterized in that... The recycling unit includes a light oil distribution pump (41), a flow controller (42), and a return pipeline (43). The flow controller (42) distributes light oil at a ratio of 7:3, with 70% being returned to the light oil blending and extraction unit and 30% being used as fuel for the secondary distillation furnace (22). The return pipeline (43) is made of seamless steel pipe.

7. A system for recycling light oil extracted from heavy oil through secondary dry distillation and blending, as described in claim 6, is characterized in that... The outer layer of the return pipeline (43) is equipped with a polyurethane insulation layer with a thickness of 50-80mm and an ultrasonic leak detector.

8. A system for recycling light oil from heavy oil secondary dry distillation and blending as described in claim 6, characterized in that, The environmental protection treatment unit includes an oily wastewater treatment device (51), a solid waste treatment device (52), and a CO2 capture device (53). The oily wastewater treatment device (51) adopts an oil waste recycling process of "air flotation + membrane filtration" with a recycling rate of ≥80%; The solid waste treatment device (52) shapes the heavy slag produced by the secondary dry distillation unit to produce fuel oil; and solidifies the rock cuttings produced during the mining process for use in well site road paving. The CO2 capture device (53) uses the amine method to absorb CO2, with a capture rate of ≥85%.

9. A system for recycling light oil from heavy oil secondary dry distillation and blending as described in claim 8, characterized in that, The CO2 captured by the CO2 capture device (53) is reinjected into the formation through the injection well for oil displacement, thereby increasing production capacity by 8%-10%.

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