An oil-based rock cuttings oil separation device

Abstract

The present invention provides an oil-contamination separation device for oil-based rock cuttings, which relates to the technical field of oil-based rock cuttings processing. The oil-contamination separation device for oil-based rock cuttings includes a rotary kiln, a heating furnace, and a gas collection hood. The heating furnace is arranged outside the rotary kiln and is used to heat the rotary kiln. The gas collection hood is arranged inside the rotary kiln and is used to collect oil and water vapor evaporated from the oil-based rock cuttings. The gas collection hood is connected to a gas discharge pipe, which extends to the outside of the rotary kiln and is connected to a gas recovery mechanism. The discharge port of the rotary kiln is connected to a dry slag recovery mechanism. The oil-contamination separation device for oil-based rock cuttings of the present invention realizes material and gas diversion in the rotary kiln, preventing dust from entering the oil vapor at the source and causing condensation to produce a large amount of secondary hazardous waste. The oil vapor evaporated from the high-temperature section and the low-temperature section of the rotary kiln is transported separately, preventing a large amount of low-boiling-point light oil from cracking or carbonizing in the kiln, thereby improving the yield and quality of recovered oil.

Description

Technical Field

[0001] The invention relates to the technical field of oil-based rock cuttings processing, in particular to an oil-pollution separation device for oil-based rock cuttings. Background Art

[0002] Oily sludge from oil-based cuttings is formed during shale gas extraction due to the artificial addition of diesel, white oil, and other additives to horizontal well construction. The oil added to cool and lubricate drilling equipment is not chemically bonded to the mixture of mud and water. This allows the oil, water, and sludge to be separated by heating in the absence of oxygen, leveraging the different boiling points of oil and water. Therefore, the most widely used treatment method in the industry is indirect heating and oxygen-free distillation. Compared to incineration and chemical washing, this method offers higher efficiency, lower environmental risks, and higher oil recovery.

[0003] like Figure 1 As shown, a conventional oxygen-free distillation apparatus for oil-based rock cuttings comprises a sealed rotary still 11, an external heating jacket 12, a gas collection hood 14, a water-cooled spray tower 16, and an oil-water mixing tank 18. Its operating principle is as follows: Recycled oil or natural gas is used as fuel to heat the interlayer between the external heating jacket 12 and the rotary still 11 to a temperature of 450-600°C. Heat is then transferred to the oil-based rock cuttings within the still 11 through the outer wall of the rotary still 11. The rock cuttings are transported to the rotary still 11 via a rock cutting conveying system 110. Once heated to a certain temperature, the oil and water vapor within them begins to evaporate. As the material rotates with the rotary still 11, it moves toward the gas collection hood 14. As the temperature gradually rises, the oil and water within the material continuously vaporize into high-temperature steam until it reaches the outlet of the rotary still 11. The high-temperature steam and dry oil-based rock cuttings residue enter the gas collection hood 14 through a spiral discharge pipe 13. The dry slag falls within the gas collection hood 14 to the dry slag discharge port 19 and is discharged from the dry slag discharge port 19. The mixed vapor is sucked into the spray tower 16 through the steam extraction pipe 15 by the exhaust fan 17. A cooling water nozzle is installed at the top of the spray tower 16. The sprayed cooling water, water cooled from the high-temperature gas, oil, and dust are simultaneously discharged into the oil-water mixing tank 18. As long as the oil-water mixing tank 18 is large enough, the oil, water, and dust can be separated through natural sedimentation over a long period of time.

[0004] In traditional anaerobic distillation technology, after oil-based rock cuttings are heated in an anaerobic distillation unit, the oil and water in the rock cuttings are transformed into a mixed vapor at a high temperature of approximately 320-350°C. This high-temperature mixed vapor and a large amount of rock cutting dust are simultaneously discharged through the outlet of the rotary distillation furnace 11 into the gas collection hood 14. The high-temperature mixed vapor is then drawn into the spray tower 16 through a steam extraction pipe 15 located at the top. During this extraction process, the dust falls under the action of gravity to the dry residue discharge port 19 located at the bottom of the gas collection hood 14 for discharge. During this process, due to the combined effects of the rotation of the rotary distillation furnace 11, the suction of the exhaust fan 17, and the falling of a large amount of oil-based rock cutting dry residue, the high-temperature oil vapor, carrying a large amount of dust, is drawn into the spray tower 16, causing pipe blockage. The large amount of dust contained in the oil and water produces a large amount of secondary sludge with high oil and water content at the bottom of the oil-water mixing tank 18. A large amount of fine dust is suspended in the collected condensed water and condensed oil, increasing the difficulty of oil-water separation. In addition, a large amount of light oil in the rotary distillation furnace 11 is partially cracked due to the high internal temperature, making it difficult to control the quality of recovered diesel and white oil. The recovered oil products are generally of low quality, with high water content, heavy ash content, and turbid color. It is difficult to recycle them directly as fuel in the factory, and the market price is not high, which affects the quality of the recovered oil. Summary of the Invention

[0005] The purpose of the present invention is to provide an oil-based rock cuttings oil-pollution separation device to solve the problem in the prior art that the oil-based rock cuttings carry a large amount of dust in the high-temperature oil vapor formed after anaerobic distillation. The oil-based rock cuttings oil-pollution separation device of the present invention can separate the high-temperature vapor and material dust in the rotary kiln, avoiding a large amount of fine dust from entering the vapor, reducing the dust content in the vapor, and solving the problems of high dust content in the condensate, pipe blockage and large amount of secondary hazardous waste generation from the source.

[0006] The present invention provides an oil-pollution separation device for oil-based rock cuttings, comprising a rotary kiln, a heating furnace and a gas collection hood, wherein the heating furnace is arranged on the outside of the rotary kiln and is used to heat the rotary kiln, the gas collection hood is arranged on the inside of the rotary kiln and is used to collect oil and water vapor evaporated from the oil-based rock cuttings, the gas collection hood is connected to a gas exhaust pipe, the gas exhaust pipe extends to the outside of the rotary kiln and is connected to a gas recovery mechanism, and the discharge port of the rotary kiln is connected to a dry slag recovery mechanism.

[0007] As a preferred solution of the present invention, the gas collection hood has a trumpet-shaped structure, and the small-diameter end of the gas collection hood is connected to the gas exhaust pipe. The central axis of the gas collection hood is arranged parallel to the central axis of the rotary kiln, and a gap is provided between the gas collection hood and the inner wall of the rotary kiln.

[0008] As a preferred solution of the present invention, the heating furnace includes a low-temperature heating furnace and a high-temperature heating furnace, and the low-temperature heating furnace and the high-temperature heating furnace are respectively arranged on the outside of the rotary furnace along the material conveying direction of the rotary furnace, and the gas collection cover includes a low-temperature collection cover and a high-temperature collection cover, and the low-temperature collection cover is correspondingly arranged in the rotary furnace at the rear end of the low-temperature heating furnace, and the high-temperature collection cover is correspondingly arranged in the rotary furnace at the rear end of the high-temperature heating furnace.

[0009] As a preferred solution of the present invention, the low-temperature collection hood is connected to the low-temperature gas exhaust pipe, and the high-temperature collection hood is connected to the high-temperature gas exhaust pipe. The low-temperature gas exhaust pipe is arranged through the high-temperature collection hood and the high-temperature gas exhaust pipe in sequence, and the outlet end of the low-temperature gas exhaust pipe and the outlet end of the high-temperature gas exhaust pipe are both connected to the gas recovery mechanism; a high-temperature resistant thermal insulation coating is provided on the outer walls of the low-temperature collection hood and the low-temperature gas exhaust pipe.

[0010] As a preferred solution of the present invention, the gas recovery mechanism includes a head gas collecting hood, a heat exchanger and a mixed liquid collection box. One side of the head gas collecting hood is connected to the outlet end of the low-temperature gas exhaust pipe and the outlet end of the high-temperature gas exhaust pipe. The heat exchanger is connected to the top of the head gas collecting hood through an exhaust pipe. The mixed liquid collection box is connected to the bottom of the heat exchanger. A fan is connected to the top of the heat exchanger.

[0011] As a preferred solution of the present invention, the dry slag recovery mechanism includes a spiral feeding pipe and a head collecting cover, the discharge port of the rotary kiln is connected to a dry slag lifting device, one end of the spiral feeding pipe is connected to the dry slag lifting device and the other end is connected to the head collecting cover.

[0012] As a preferred solution of the present invention, the dry slag recovery mechanism also includes a dry slag silo, which is arranged below the head air collecting hood and the head material collecting hood, and the bottom end of the head material collecting hood is connected to the dry slag silo, and an ash unloading and air locking valve is provided at the bottom end of the head air collecting hood, and the bottom end of the head air collecting hood is connected to the dry slag silo.

[0013] As a preferred embodiment of the present invention, the dry slag recovery mechanism further includes a weighing sensor and a dry slag conveyor. The weighing sensor is arranged in the dry slag silo. The dry slag conveyor is transversely arranged at the bottom end of the dry slag silo and is used to transversely convey the dry slag that falls from the dry slag silo into the dry slag conveyor.

[0014] As a preferred solution of the present invention, the rear end of the blower is connected to a non-condensable gas pipeline, and the non-condensable gas pipeline is connected to the heating furnace.

[0015] Compared with the prior art, the present invention has the following positive effects:

[0016] The oil-pollution separation device for oil-based rock cuttings provided by the present invention includes a rotary kiln, a heating furnace and a gas collection hood. The heating furnace is arranged on the outside of the rotary kiln and is used to heat the rotary kiln. The gas collection hood is arranged inside the rotary kiln and is used to collect oil and water vapor evaporated from the oil-based rock cuttings. The gas collection hood is connected to a gas exhaust pipe, and the gas exhaust pipe extends to the outside of the rotary kiln and is connected to a gas recovery mechanism. The discharge port of the rotary kiln is connected to a dry slag recovery mechanism. During use of the oil-based rock cuttings oil separation device of the present invention, the feeding device conveys the oil-based rock cuttings to the rotary kiln, the heating furnace heats the rotary kiln, the rotary kiln rotates, and the oil-based rock cuttings are evenly heated in the rotary kiln. As the temperature increases, the moisture and oil contained in the oil-based rock cuttings evaporate to form oil-water vapor, and the oil-water vapor is collected by a gas collection hood and sent to the gas recovery mechanism outside the rotary kiln through a gas discharge pipe for recovery. The dry slag is transported to the dry slag recovery mechanism through the discharge port of the rotary kiln, so that the dry slag and steam flow out of the rotary kiln through different channels and are collected separately, realizing material and gas diversion, so that the steam and dry slag materials are completely non-contact during the conveying process, avoiding a large amount of fine dust from entering the steam, reducing the dust content in the steam, making the separation of condensed water and condensed oil formed after the steam condenses easier, and reducing the cost of oil-water separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a schematic diagram of the structure of a traditional oil-based rock cuttings oxygen-free distillation device;

[0019] Figure 2 It is a structural schematic diagram of the oil-based rock cuttings oil separation device in the present invention.

[0020] Figure 11, rotary distillation furnace; 12, external heating jacket; 13, spiral discharge pipe; 14, gas collection hood; 15, steam extraction pipeline; 16, spray tower; 17, exhaust fan; 18, oil-water mixing tank; 19, dry slag discharge port; 110, oil-based cuttings conveying system; 21, rotary furnace; 22, low-temperature collection hood; 23, low-temperature gas discharge pipe; 24, first fixed frame; 25, high-temperature collection hood; 26, second fixed frame; 27, high-temperature gas discharge pipe; 28, dry slag lifting device; 29, spiral conveyor Material pipe; 210, head material collection hood; 211, head air collection hood; 212, exhaust pipe; 213, heat exchanger; 214, fan; 215, circulating cooling water inlet; 216, circulating cooling water outlet; 217, mixed liquid collection box; 218, non-condensable gas transmission pipe; 219, ash unloading air lock valve; 220, metal corrugated hose; 221, dry slag silo; 222, weighing sensor; 223, dry slag conveyor; 224, high-temperature heating furnace; 225, low-temperature heating furnace; 226, feeding device. DETAILED DESCRIPTION

[0021] In the description of the present invention, it should be noted that, unless otherwise specified, "plurality" means two or more; the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "front end", "back end", "head", "tail", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0022] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

[0023] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Example 1:

[0025] This embodiment provides an oil-based rock cuttings oil separation device, such as Figure 1-Figure 2As shown, the rotary kiln 21 includes a heating furnace, a gas collection hood, and a heating furnace. The heating furnace is located outside the rotary kiln 21 and is used to heat the rotary kiln. The gas collection hood is located inside the rotary kiln 21 and is used to collect oil and water vapor evaporated from the oil-based rock cuttings. The gas collection hood is connected to a gas discharge pipe, which extends outside the rotary kiln and is connected to a gas recovery mechanism. The discharge port of the rotary kiln 21 is connected to a dry slag recovery mechanism.

[0026] During use of the oil-based rock cuttings oil separation device of this embodiment, the feed port of the rotary kiln 21 is connected to the feed device 226, the feed device 226 conveys the oil-based rock cuttings to the rotary kiln 21, the heating furnace heats the rotary kiln 21, the rotary kiln rotates, and the oil-based rock cuttings are evenly heated in the rotary kiln. As the temperature increases, the moisture and oil contained in the oil-based rock cuttings evaporate to form oil-water vapor, which is collected by the gas collection hood and sent to the gas recovery mechanism outside the rotary kiln through the gas discharge pipe for recovery. The dry slag is transported to the dry slag recovery mechanism through the discharge port of the rotary kiln 21, so that the dry slag and steam flow out of the rotary kiln 21 through different channels and are collected separately, realizing material and gas diversion, avoiding secondary mixing of high-temperature dry slag and steam at the outlet of the rotary kiln 21, resulting in difficulty in separation in the discharge hood, and a large amount of dust enters the distillation gas, causing negative impact on the rear-end condensation separation.

[0027] In the present embodiment, the oil separation device for oil-based rock cuttings collects steam through a gas collection hood to realize material-gas diversion of steam and dry residue material in the distillation furnace, thereby preventing dust from entering the oil vapor at the source, and making the steam and dry residue material completely non-contact during the transmission process, thereby preventing a large amount of fine dust from entering the steam, reducing the dust content in the steam, and avoiding a large amount of oily sludge generated by dust during the condensation process, making it easier to separate the condensed water and condensed oil formed after the steam condenses, and reducing the cost of oil-water separation.

[0028] Preferably, the gas collection hood has a trumpet-shaped structure, with the small-diameter end of the gas collection hood connected to the gas exhaust pipe. The central axis of the gas collection hood is arranged parallel to the central axis of the rotary kiln 21, and a gap is provided between the gas collection hood and the inner wall of the rotary kiln 21. The diameter of the gas collection hood gradually decreases along the material conveying direction.

[0029] There is a fixed gap between the bell mouth of the gas collecting hood and the inner wall of the rotary kiln 21 in this embodiment, such as Figure 2As shown, materials moving along the rotary kiln 21 can pass through the gap and enter the right side of the gas collection hood from the left side. The oil-water vapor formed by the evaporation of oil-based rock cuttings is discharged through the gas discharge pipe under the action of a slight positive pressure at the bell mouth of the gas collection hood. Trace dust or secondary dust carried in the gas can fall back into the rotary kiln 21 through the inclined surface of the bell mouth. As the rotary kiln 21 rotates and the gas evaporates, some fine dust is carried into the evaporating gas within the kiln. However, due to the low steam velocity, it cannot carry the dust further forward, and some of the dust falls back down. Other fine dust is carried forward with the gas flow. As the diameter of the bell-shaped gas collection hood changes during this process, the resistance encountered by the steam changes continuously, causing turbulence, which weakens its dust-carrying capacity. Some dust then falls from the steam onto the inclined surface of the bell mouth and back into the rotary kiln 21, thus separating the dust from the steam.

[0030] Preferably, the heating furnace includes a low-temperature heating furnace 225 and a high-temperature heating furnace 224, which are respectively arranged in sequence on the outside of the rotary kiln 21 along the material conveying direction of the rotary kiln 21. The gas collection hood includes a low-temperature collection hood 22 and a high-temperature collection hood 25. The low-temperature collection hood 22 is correspondingly arranged in the rotary kiln 21 at the rear end of the low-temperature heating furnace 225, and the high-temperature collection hood 25 is correspondingly arranged in the rotary kiln 21 at the rear end of the high-temperature heating furnace 224. The low-temperature collection hood 22 and the high-temperature collection hood 25 are connected to the interior of the rotary kiln 21 via a first fixing bracket 24 and a second fixing bracket 26, respectively. Both the low-temperature collection hood 22 and the high-temperature collection hood 25 rotate with the rotation of the rotary kiln 21. The low-temperature collection hood 22 is arranged between the low-temperature section and the high-temperature section of the rotary kiln, and the high-temperature collection hood 25 is arranged between the high-temperature section and the discharge port of the rotary kiln.

[0031] Since the main hydrocarbon substances such as diesel and white oil added to the oil-based rock chips begin to volatilize in large quantities above 150°C, and volatilize close to 70% at 180-200°C, when the material temperature exceeds 350°C, the volatile matter in the rock chips is less than 0.15%, which is lower than the disposal requirement of less than 0.3%. Therefore, in this embodiment, two independent heating chambers are set to indirectly heat the rotary kiln 21, such as Figure 2As shown, the rotary kiln 21 is divided into two heating sections: low-temperature and high-temperature. Material enters the rotary kiln 21 from the right side and first enters the low-temperature section, heated by the low-temperature heating furnace 225. As the rotary kiln 21 rotates, it gradually enters the high-temperature section, heated by the high-temperature heating furnace 224. The mixed vapor temperature in the low-temperature section is controlled to not exceed 200°C, completely evaporating over 70% of the oil and 100% of the water in the oil-based cuttings. This lower temperature reduces the volume of the mixed vapor, preventing excessive dust carryover and minimizing the cracking of light oil, thereby increasing oil recovery and improving the quality of the recovered oil. The gas temperature in the high-temperature section is controlled between 320°C and 350°C to ensure the complete volatilization of the approximately 30% of heavier oil remaining in the dry cuttings. The evaporated oil vapor from the high-temperature and low-temperature sections of the rotary kiln 21 is transported separately, preventing the cracking or carbonization of large amounts of low-boiling-point light oil within the furnace, thereby improving the yield and quality of the recovered oil.

[0032] Preferably, the low-temperature collection hood 22 is connected to the low-temperature gas exhaust pipe 23, and the high-temperature collection hood 25 is connected to the high-temperature gas exhaust pipe 27. The low-temperature gas exhaust pipe 23 is sequentially arranged through the high-temperature collection hood 25 and the high-temperature gas exhaust pipe 27. The outlet end of the low-temperature gas exhaust pipe 23 and the outlet end of the high-temperature gas exhaust pipe 27 are both connected to a gas recovery mechanism. The gas recovery mechanism collects steam from the low-temperature section and steam from the high-temperature section at the same time. The outer diameter of the low-temperature gas exhaust pipe 23 is smaller than the inner diameter of the high-temperature gas exhaust pipe 27. A high-temperature resistant heat-insulating coating is provided on the outer walls of the low-temperature collection hood 22 and the low-temperature gas exhaust pipe 23 to prevent heat radiation from the high-temperature section material and the inner wall of the rotary kiln 21, and to prevent the internal gas from being secondary heated and cracking or carbonizing.

[0033] Preferably, the gas recovery mechanism includes a head gas collecting hood 211, a heat exchanger 213 and a mixed liquid collection box 217. One side of the head gas collecting hood 211 is connected to the outlet end of the low-temperature gas exhaust pipe 23 and the outlet end of the high-temperature gas exhaust pipe 27. The heat exchanger 213 is connected to the top of the head gas collecting hood 211 through an exhaust pipe 212. The mixed liquid collection box 217 is connected to the bottom of the heat exchanger 213, and a fan 214 is connected to the top of the heat exchanger 213. The heat exchanger 213 is a vertical pipe water-cooled heat exchanger. A circulating cooling water inlet 215 and a circulating cooling water outlet 216 are provided on the heat exchanger 213. The circulating cooling water inlet 215 and the circulating cooling water outlet 216 are respectively provided at the upper and lower ends of the heat exchanger 213.

[0034] The oil- and water-containing mixed vapor is transferred from the low-temperature gas exhaust pipe 23 and the high-temperature gas exhaust pipe 27 to the head gas collection hood 211. Under the suction action of the fan 214, the mixed vapor is sent along the exhaust pipe 212 to the heat exchanger 213. As the mixed vapor flows upward in the head gas collection hood 211, a small amount of dust contained in the vapor falls to the bottom of the head gas collection hood 211 under the action of gravity, and is separated from the mixed vapor, further purifying the mixed vapor. The mixed vapor is water-cooled in the heat exchanger 213 and condensed to form condensed oil and condensed water. The condensed oil-water mixture flows to the mixed liquid collection tank 217, where it is separated into layers, thereby separating the oil and water.

[0035] Preferably, the dry slag recovery mechanism includes a spiral conveying pipe 29 and a head collecting cover 210, the discharge port of the rotary kiln 21 is connected to the dry slag lifting device 28, one end of the spiral conveying pipe 29 is connected to the dry slag lifting device 28 and the other end is connected to the head collecting cover 210.

[0036] The dry slag is conveyed to the dry slag lifting device 28 through the discharge port of the rotary kiln 21, and is then conveyed to the head collecting cover 210 through the dry slag lifting device 28 and the spiral conveying pipe 29 for collection of the dry slag.

[0037] Preferably, the dry slag recovery mechanism further includes a dry slag bin 221, which is disposed below the head air collection hood 211 and the head material collection hood 210. The bottom end of the head material collection hood 210 is connected to the dry slag bin 221. A dust discharge and air lock valve 219 is disposed at the bottom end of the head air collection hood 211, and the bottom end of the head air collection hood 211 is connected to the dry slag bin 221. A small amount of dust that falls into the head air collection hood 211 and a large amount of dry slag material collected in the head material collection hood 210 are both collected in the dry slag bin 221. When the dry slag in the head material collection hood 210 is discharged into the dry slag bin 221, the dust discharge and air lock valve 219 is closed, and the bottom end of the head air collection hood 211 is sealed to prevent dust stirred up in the dry slag bin 221 from entering the head air collection hood 211.

[0038] Preferably, the dry slag recovery mechanism also includes a weighing sensor 222 and a dry slag conveyor 223. The weighing sensor 222 is disposed within the dry slag silo 221. The dry slag conveyor 223 is disposed transversely at the bottom of the dry slag silo 221 and is used to laterally convey the dry slag that has fallen from the dry slag silo 221 into the dry slag conveyor 223. The dry slag conveyor is a screw conveyor. The weighing sensor 222 and the dry slag conveyor 223 control the material level within the dry slag silo 221 to form a suitable material column, thereby effectively sealing the discharge system of the device.

[0039] Preferably, the rear end of fan 214 is connected to a non-condensable gas pipeline 218, which is connected to a heating furnace. This pipeline is then connected to a high-temperature heating furnace 224. Non-condensable gas is typically an organic gas. This non-condensable gas is passed through pipeline 218 into high-temperature heating furnace 224 for combustion. This not only disposes of the non-condensable gas but also aids combustion, recovering the heat released by combustion and contributing to environmental protection.

[0040] When the oil-based rock cuttings separation device of this embodiment is in operation, the pre-treated, evenly dispersed oil-based rock cuttings are transported to the rotary kiln 21 via the feed device 226. Under indirect heating from the low-temperature heating furnace 225, the internal gas temperature of the rotary kiln 21 gradually rises to 180-200°C, evaporating a large amount of oil and water vapor. Under internal pressure, the evaporated oil and water vapor enter the low-temperature collection hood 22. Some of the carried dust and secondary dust generated during the rotation of the rotary kiln 21 fall onto the inclined surface of the bell mouth of the low-temperature collection hood 22 and fall back to the bottom of the rotary kiln 21. A large amount of gas enters the head gas collection hood 211 through the low-temperature gas discharge pipe 23. Because the outer wall of the low-temperature gas discharge pipe 23 is coated with a high-temperature resistant insulation layer, although the low-temperature gas discharge pipe passes through the high-temperature section, it has little effect on the temperature of the mixed gas within the pipe. The material, after most of the gas evaporates in the low-temperature section, enters the high-temperature section of the rotary kiln 21 through the gap between the edge of the low-temperature collection hood 22 and the inner wall of the rotary kiln 21 as the rotary kiln 21 rotates. Under indirect heating from the high-temperature heating furnace 224, the internal temperature of the high-temperature section of the rotary kiln 21 gradually rises to 320-350°C. The small amount of high-temperature gas that evaporates is discharged through the high-temperature collection hood 25, following the same principle as the discharge of gas from the low-temperature section.

[0041] As the rotary kiln 21 rotates, the qualified oil-based rock cuttings dry residue that has passed the high-temperature treatment enters the discharge area at the head through the gap between the high-temperature collection cover 25 and the inner wall of the rotary kiln 21. After being lifted to the middle and upper part of the drum wall by the dry residue lifting device 28, it enters the spiral conveying pipe 29. The spiral conveying pipe 29 rotates with the rotary kiln 21, conveying the oil-based rock cuttings dry residue into the dry residue silo 221. The material level in the dry residue silo 221 is controlled by the weighing sensor 222 and the dry residue conveyor 223 to form a suitable material column.

[0042] The low-temperature and high-temperature steam transported by the low-temperature gas discharge pipe 23 and the high-temperature gas discharge pipe 27 converge in the head gas collection hood 211. A small amount of dust carried and settled in the pipe enters the head gas collection hood 211 as the rotary kiln 21 rotates, and then enters the dry slag bin 221 through the ash discharge and air lock valve 219 located at the bottom of the head gas collection hood 211. The ash discharge and air lock valve 219 separates the dry slag bin 221 from the head gas collection hood 211, preventing a large amount of secondary dust from entering the dry slag bin 221 when the oil-based rock cuttings dry slag discharged through the spiral feeding pipe 29 falls into the dry slag bin 221.

[0043] The internal pressure of the head gas hood 211 is controlled by a fan 214 within a range of 0-+100 Pa to prevent negative pressure from drawing fine dust from the rotary kiln 21 into the condenser. Under the action of a slightly positive internal pressure, the high-temperature oil-water vapor mixture enters the heat exchanger 213 through the exhaust pipe 212 for indirect water-cooling heat exchange. The condensed oil-water mixture enters the mixed liquid collection tank 217 below the heat exchanger 213 and is separated by gravity settling. After simple settling separation, the upper layer of liquid is clear and transparent recovered oil, the lower layer is water, and the bottom layer contains a very small amount of fine dust precipitation. A small amount of non-condensable gas enters the high-temperature heating furnace 224 through the non-condensable gas transmission pipe 218 for combustion.

[0044] Dynamic and static sealing structures are used to effectively seal between the head gas collecting cover 211 and the high-temperature gas discharge pipe 27, as well as between the head material collecting cover 210 and the spiral material conveying pipe 29, to ensure that the system pressure is between +200Pa-200Pa.

[0045] The above method significantly reduces the risk of high-temperature cracking and carbonization of oil vapor, while also significantly reducing the volume expansion and dust carryover of the mixed vapor. This allows the system to collect relatively clean, high-temperature oil-water mixed vapor and condense it into a mixed oil-water liquid via a riser water-cooled heat exchanger. Gravity separation of the mixed liquid yields highly clean, transparent recovered oil. This also prevents large amounts of dust from settling in the mixed liquid collection tank 217, which could then form difficult-to-dispose, high-water and oil-rich sludge.

[0046] The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with this technical field can make several modifications and improvements without departing from the creative concept of the present invention, which should be included in the protection scope of the present invention.

Claims

1. An oil-based rock cuttings oil separation device, characterized in that: The rotary kiln (21) comprises a rotary kiln (21), a heating furnace and a gas collection hood, wherein the heating furnace is arranged outside the rotary kiln (21) and is used to heat the rotary kiln, the gas collection hood is arranged inside the rotary kiln (21) and is used to collect oil and water vapor evaporated from oil-based rock cuttings, the gas collection hood is connected to a gas discharge pipe, the gas discharge pipe extends to the outside of the rotary kiln and is connected to a gas recovery mechanism, and the discharge port of the rotary kiln (21) is connected to a dry slag recovery mechanism; The heating furnace includes a low-temperature heating furnace (225) and a high-temperature heating furnace (224), and the low-temperature heating furnace (225) and the high-temperature heating furnace (224) are respectively arranged in sequence on the outside of the rotary furnace (21) along the material conveying direction of the rotary furnace (21); the gas collection cover includes a low-temperature collection cover (22) and a high-temperature collection cover (25), and the low-temperature collection cover (22) is correspondingly arranged in the rotary furnace (21) at the rear end of the low-temperature heating furnace (225), and the high-temperature collection cover (25) is correspondingly arranged in the rotary furnace (21) at the rear end of the high-temperature heating furnace (224); The low-temperature collection cover (22) is connected to the low-temperature gas discharge pipe (23), and the high-temperature collection cover (25) is connected to the high-temperature gas discharge pipe (27). The low-temperature gas discharge pipe (23) is sequentially arranged through the high-temperature collection cover (25) and the high-temperature gas discharge pipe (27), and the outlet end of the low-temperature gas discharge pipe (23) and the outlet end of the high-temperature gas discharge pipe (27) are both connected to the gas recovery mechanism; a high-temperature resistant heat-insulating coating is provided on the outer walls of the low-temperature collection cover (22) and the low-temperature gas discharge pipe (23).

2. The oil-based rock cuttings oil separation device according to claim 1, characterized in that: The gas collection hood has a trumpet-shaped structure, and the small-diameter end of the gas collection hood is connected to the gas exhaust pipe. The central axis of the gas collection hood is arranged parallel to the central axis of the rotary kiln (21), and a gap is provided between the gas collection hood and the inner wall of the rotary kiln (21).

3. The oil-based rock cuttings oil separation device according to claim 1, characterized in that: The gas recovery mechanism comprises a head gas collecting hood (211), a heat exchanger (213) and a mixed liquid collection box (217); one side of the head gas collecting hood (211) is connected to the outlet end of the low-temperature gas discharge pipe (23) and the outlet end of the high-temperature gas discharge pipe (27); the heat exchanger (213) is connected to the top of the head gas collecting hood (211) via an exhaust pipe (212); the mixed liquid collection box (217) is connected to the bottom of the heat exchanger (213); and a fan (214) is connected to the top of the heat exchanger (213).

4. The oil-based rock cuttings oil separation device according to claim 3, characterized in that: The dry slag recovery mechanism comprises a spiral feed pipe (29) and a head collecting cover (210); the discharge port of the rotary kiln (21) is connected to a dry slag lifting device (28); one end of the spiral feed pipe (29) is connected to the dry slag lifting device (28) and the other end is connected to the head collecting cover (210).

5. The oil-based rock cuttings oil separation device according to claim 4, characterized in that: The dry slag recovery mechanism further comprises a dry slag bin (221), the dry slag bin (221) being arranged below the head gas collecting hood (211) and the head material collecting hood (210), the bottom end of the head material collecting hood (210) being connected to the dry slag bin (221), an ash unloading and air locking valve (219) being arranged at the bottom end of the head gas collecting hood (211), and the bottom end of the head gas collecting hood (211) being connected to the dry slag bin (221).

6. The oil-based rock cuttings oil separation device according to claim 5, characterized in that: The dry slag recovery mechanism further comprises a weighing sensor (222) and a dry slag conveyor (223), wherein the weighing sensor (222) is arranged in the dry slag silo (221), and the dry slag conveyor (223) is transversely arranged at the bottom end of the dry slag silo (221) and is used to transversely convey the dry slag that falls from the dry slag silo (221) into the dry slag conveyor (223).

7. The oil-contamination separation device for oil-based rock cuttings according to claim 3, characterized in that: The rear end of the fan (214) is connected to a non-condensable gas delivery pipe (218), and the non-condensable gas delivery pipe (218) is connected to the heating furnace.

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