Method and device for producing fuel oil by modifying coal-to-olefin

Abstract

The invention discloses a method and device for producing fuel oil through coal-to-olefin modification, and relates to the technical field of fuel oil production, and the method comprises the following steps: 1, coal slurry gasification and synthesis gas preparation; 2, preparing olefin from the synthesis gas through a one-step method; 3, olefin separation and light hydrocarbon recovery; step 4, olefin oligomerization-hydrogenation integrated modification; and step 5, fractionation and carbon circulation. By arranging the switching mechanism and the sewage discharging mechanism, a toothed plate moves downwards and makes contact with a first straight gear, the bottom of the furnace body is closed, cold water above a fixing ring can continue to be subjected to water bath operation at the moment, then the toothed plate makes contact with a third straight gear, a baffle is driven to rotate, and a sewage discharging pipe is opened; sewage above the baffle is discharged through a blow-off pipe; and when the toothed plate is reset, the baffle rotates to close the blow-off pipe, and then the bottom end of the furnace body is opened, so that sewage in the water-cooled wall gasification furnace is conveniently discharged under the condition of no shutdown.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel oil production, in particular to a method and device for producing fuel oil by utilizing coal-to-olefin modification. Background Art

[0002] Coal-to-liquids is a technology that uses coal as raw material to produce oil and petrochemical products through chemical processing. It includes two technical routes: direct coal liquefaction and indirect coal liquefaction. Direct coal liquefaction directly liquefies coal under high temperature and high pressure conditions through catalytic hydrogenation to synthesize liquid hydrocarbon fuel, and removes sulfur, nitrogen, oxygen and other atoms. It has poor adaptability to coal types, harsh reaction and operating conditions, and the output fuel has high impurity content such as aromatics, sulfur and nitrogen, and low cetane number. It is difficult to use it directly in the engine. The Fischer-Tropsch synthesis process is based on The process of preparing hydrocarbon compounds using synthesis gas as raw material. Synthesis gas can be prepared from natural gas, coal, light hydrocarbons, heavy oil, biomass and other raw materials. Depending on the raw materials of synthesis gas, Fischer-Tropsch synthesis oil can be divided into: coal-to-liquids and natural gas-to-liquids. The indirect liquefaction of coal first gasifies the coal and then converts it into hydrocarbon fuel through Fischer-Tropsch synthesis. The produced oil has the characteristics of high cetane number, high H / C content, low sulfur and low aromatics, and can be miscible with ordinary diesel in any proportion. At the same time, CTL has the characteristics of low kinematic viscosity, low density, and low volume calorific value.

[0003] In the process of producing fuel oil by using coal-to-olefin modification, a water-cooled wall gasifier is required. During use, the synthesis gas generated by water-coal slurry and pure oxygen under high temperature is introduced into water for water bathing, so that the slag in the gas is solidified. After long-term operation, the impurities in the water increase, which is easy to affect the gas water bath, and the wastewater needs to be discharged regularly. However, when discharging the wastewater, it is necessary to shut down the machine before performing the discharge operation, which reduces the production efficiency of the fuel oil. In order to achieve the purpose of conveniently discharging the wastewater in the water-cooled wall gasifier, a method and apparatus for producing fuel oil by using coal-to-olefin modification are provided. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for producing fuel oil by modifying coal to olefins in order to facilitate the discharge of sewage in a water-cooled wall gasifier.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for producing fuel oil by using coal-to-olefin modification, comprising the following steps: Step 1, coal slurry gasification and synthesis gas preparation: the raw coal after impurity removal and screening is ground into a particle size D90 ≤ 100μm in a vertical roller mill, mixed with 60℃ hot water at a mass ratio of coal:water = 62:38, and 0.1% sodium lignin sulfonate dispersant is added to prepare a water-coal slurry with a viscosity of 600±50cP. The prepared water-coal slurry and pure oxygen are sprayed into a water-cooled wall gasifier at an oxygen-coal ratio of 0.8 Nm³ / kg. The reaction is carried out at a pressure of 6.5MPa and a temperature of 1350±20℃ for 4-6 seconds to generate a crude synthesis gas with a CO content of 46-48%, a H2 content of 42-44%, and a CO2 content of 5-7%; Step 2: One-step synthesis of olefins from synthesis gas: The crude synthesis gas prepared in step 1 is preheated to 420°C via a plate heat exchanger, mixed with the circulating gas at a ratio of H2 / CO=1.95, and then fed into a radial flow fluidized bed reactor at a pressure of 2.5 MPa, a temperature of 380±5°C, and a space velocity of 800 h -1 Under the conditions, ZnCrAlO x @SAPO-34 core-shell catalyst produces olefin-containing reaction gas; Step 3, olefin separation and light hydrocarbon recovery: The olefin-containing reaction gas prepared in step 2 is pressurized to 3.0 MPa by a three-stage centrifugal compressor, enters a molecular sieve adsorption tower for dehydration to a dew point of ≤-70°C, and then enters an oil absorption separation tower for separation at a tower pressure of 3.0 MPa, a pre-cutting section temperature of -25°C, and an oil absorption section temperature of -40°C; C2 light hydrocarbons with an ethane content of ≥95% are output from the top of the tower and returned to step 2 as dilution gas, and a C3-C4 olefin mixture is output from the bottom of the tower; Step 4: Olefin polymerization-hydrogenation integrated modification: The C3-C4 olefin component prepared in step 3 is fed into the upper section of the fixed bed reactor and heated at a temperature of 180±5°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 Under the conditions of 280℃±5℃, 6.0MPa and 300:1 hydrogen-to-oil volume ratio, the oligomers are catalyzed and saturated by the hydrogenation catalyst to obtain alkane products. Step 5, fractionation and carbon cycle: The alkane product prepared in step 4 is heated to 380°C in a tubular heating furnace and cut into fractions in a vacuum distillation tower: the 180-260°C fraction is light fuel oil, and the 260-350°C fraction is medium fuel oil.

[0006] A device for producing fuel oil by modifying coal to olefins, the water-cooled wall gasification furnace described in step 1 includes a support frame, the outer wall of the support frame is fixedly connected to the furnace body, the top of the furnace body is provided with a combustion chamber, the inner wall of the combustion chamber is installed with a water-cooling coil, the top of the combustion chamber is installed with a process burner, the interior of the furnace body is provided with a quenching ring at the bottom end of the process burner, the bottom end of the quenching ring is fixedly connected to a downpipe, the outer wall of the downpipe is fixedly sleeved with an uppipe, one side outer wall of the furnace body is fixedly connected to an exhaust pipe, the bottom end of the furnace body is fixedly connected to a drain pipe, the bottom end of the furnace body is switched by a switch mechanism, and the sewage in the drain pipe is discharged through the drain mechanism.

[0007] As a further solution of the present invention: the switch mechanism includes a fixing ring, the fixing ring is fixedly connected to the bottom wall of the furnace body, the inner wall of the sewage pipe is fixedly connected to the mounting plate, the fixing ring and the mounting plate are fixedly connected to a limiting column between the fixing ring and the mounting plate, the outer wall of the limiting column is slidably connected to a blocking block, the outer wall of one side of the sewage pipe is fixedly connected to a cross plate, the outer wall of the cross plate is installed with a motor, the output end of the motor is connected to a first threaded rod, the outer wall of the first threaded rod is slidably connected to the movable plate, the outer wall of the movable plate is fixedly connected to a toothed plate, and the toothed plate slides along the outer wall of the sewage pipe. The outer wall of the sewage pipe is located on one side of the toothed plate and is rotatably connected to the first spur gear, one end of the first spur gear is fixedly connected to the connecting shaft, the outer wall of the connecting shaft is located inside the mounting plate and is fixedly connected to the first bevel gear, the inner wall of the mounting plate is located on the outer wall of the first bevel gear and is rotatably connected to the second bevel gear, the top of the second bevel gear is fixedly connected to the second threaded rod, and the second threaded rod extends to the inside of the blocking block.

[0008] The top end face of said sliding arm is fixedly provided with a toothed connecting strip which is cooperatively connected with the toothed connecting strip of said toothed connecting gear.

[0009] As a further solution of the present invention: a first threaded hole is formed on the outer wall of the movable plate, and the first threaded hole matches the first threaded rod.

[0010] As a further solution of the present invention: a tooth groove is formed on an outer wall of the tooth plate, the tooth groove is engaged with the first spur gear, and the first bevel gear is engaged with the second bevel gear.

[0011] As a further solution of the present invention: a second threaded hole is formed at the bottom end of the blocking block, and the second threaded hole matches the second threaded rod.

[0012] As a further solution of the present invention: the top end of the blocking block is conical, the outer wall of the blocking block is provided with a limiting hole, and the inner wall of the limiting hole is in contact with the outer wall of the limiting column.

[0013] As a further solution of the present invention: the outer wall of the vertical rod is provided with gear teeth, and the gear teeth are engaged with the fourth spur gear.

[0014] As a further solution of the present invention: the tooth grooves on the tooth plate are meshed with the third spur gear.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The core innovation of this invention lies in significantly improving the yield and quality of the target light / medium fuel oil through an optimized catalyst combination and process design. This invention effectively enhances product selectivity and fractionation precision, resolving the key issues of low product yield and mixed components encountered in traditional processes.

[0016] The water-cooled wall gasifier of the present invention is provided with a switch mechanism and a sewage discharge mechanism. The tooth plate moves downward and contacts the first spur gear to close the bottom of the furnace body. At this time, the cold water above the fixed ring can continue to perform a water bath operation. Afterwards, the tooth plate contacts the third spur gear, driving the baffle to rotate to open the sewage pipe, and the sewage above the baffle is discharged through the sewage pipe; when the tooth plate is reset, the baffle rotates to close the sewage pipe, and then the bottom end of the furnace body is opened, so that the sewage in the water-cooled wall gasifier can be discharged without stopping the machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of the water-cooled wall gasifier of the present invention; Figure 2 A cross-sectional view of the furnace body of the water-cooled wall gasifier of the present invention; Figure 3 A cross-sectional view of a sewage pipe of the water-cooled wall gasifier according to the present invention; Figure 4 This is a schematic diagram of the installation of the connecting shaft of the water-cooled wall gasifier of the present invention; Figure 5 This is a schematic diagram of the installation of vertical rods of the water-cooled wall gasifier of the present invention; Figure 6 This is a schematic structural diagram of the vertical rods of the water-cooled wall gasifier of the present invention; Figure 7 This is a schematic diagram of the installation of the partition of the water-cooled wall gasifier of the present invention.

[0018] In the figure: 1, support frame; 2, furnace body; 3, combustion chamber; 4, water cooling coil; 5, process burner; 6, quenching ring; 7, switch mechanism; 701, fixed ring; 702, mounting plate; 703, limit column; 704, shielding block; 705, cross plate; 706, motor; 707, first threaded rod; 708, movable plate; 709, tooth plate; 710, first straight gear; 711, connecting shaft; 712, first bevel gear; 713, second bevel gear; 7 14. Second threaded rod; 8. Drain mechanism; 801. Baffle; 802. Third spur gear; 803. Fourth spur gear; 804. Vertical rod; 805. Positioning block; 806. First chute; 807. First push plate; 808. Second chute; 809. Second push plate; 810. Water tank; 811. Water outlet pipe; 812. Partition; 813. Spring; 814. Displacement rod; 9. Downcomer; 10. Ascender; 11. Exhaust pipe; 12. Drain pipe. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected, detachably connected, or connected in one piece; they can be mechanically connected or electrically connected; they can be directly connected, or indirectly connected through an intermediate medium, or they can be internal connections between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following describes an embodiment of the present invention based on its overall structure. Example 1

[0021] A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1: Coal slurry gasification and synthesis gas preparation The raw coal (Shenhua coal, ash content 12wt%) was ground to D90 = 95μm by a vertical roller mill, mixed with 60℃ hot water at a coal:water ratio of 62:38 (mass ratio), and 0.1wt% sodium lignin sulfonate dispersant was added to prepare a water-coal slurry with a viscosity of 600cP. The water-coal slurry was mixed with pure oxygen (oxygen-coal ratio 0.8 Nm 3 / kg) was sprayed into a water-cooled wall gasifier and reacted for 5 seconds at an operating pressure of 6.5 MPa and a temperature of 1350°C to generate a crude synthesis gas with a CO content of 47.1%, a H2 content of 43.2% and a CO2 content of 6.0%.

[0022] Step 2: One-step synthesis of olefins from syngas The synthesis gas prepared in step 1 was preheated to 420°C through a plate heat exchanger, mixed with the circulating gas (H2 / CO molar ratio of 1.95) and entered the radial flow fluidized bed reactor. -1 Under the conditions, ZnCrAlO x @SAPO-34 core-shell catalyst catalyzes the reaction to produce olefin-containing reaction gas.

[0023] Step 3: Olefin separation and light hydrocarbon recovery The reaction gas prepared in step 2 was pressurized to 3.0 MPa by a three-stage centrifugal compressor and then passed into a molecular sieve adsorption tower (silicon-aluminum ratio 300:1) for dehydration to a dew point of -72°C. The dehydrated gas was then passed into an oil absorption separation tower with an operating pressure of 3.0 MPa, a pre-cutting section temperature of -25°C, and an oil absorption section temperature of -40°C. C2 light hydrocarbons with an ethane content of 96.0% were output from the top of the tower and combined and returned to step 2 as dilution gas. A C3-C4 olefin mixture containing 41.2% propylene and 49.5% butene was output from the bottom of the tower.

[0024] Step 4: Olefin polymerization-hydrogenation integrated modification The C3-C4 olefin mixture prepared in step 3 was introduced into the upper section of the fixed bed reactor at a temperature of 180°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 Under the conditions, the oligomerization reaction was carried out on the macroporous SPA catalyst (pore size 50nm), and the product distribution was: C840.5%, C 12 49.8%, C 16 9.7% (distillation range 160-320℃); the aggregated flow directly falls to the lower hydrogenation zone, under the conditions of temperature 280℃ and pressure 6.0MPa, on NiMo / Al2O3 catalyst (pore volume 0.5cm 3 / g) was hydrogenated with hydrogen (hydrogen to oil volume ratio 300:1) to obtain alkane products. The distribution of oligomerization products was: C8 35-45wt%, C 12 45-55wt%, C 16 8-12wt%.

[0025] Step 5: Fractionation and product cutting The hydrogenation product prepared in step 4 was heated to 380°C in a tubular heating furnace and then entered into a vacuum distillation tower (tower top pressure -0.08 MPa, tower bottom temperature 320°C) to cut the fraction: the 180-260°C fraction was light fuel oil (yield 45.3%, viscosity 5.1 mm 2 / s), 260-350℃ fraction is medium fuel oil (yield 39.0%, viscosity 12.5mm 2 / s).

[0026] See also Figures 1 to 7, A device for producing fuel oil by modifying coal to olefins, the water-cooled wall gasification furnace described in step 1 includes a support frame 1, the outer wall of the support frame 1 is fixedly connected to a furnace body 2, the top of the furnace body 2 is provided with a combustion chamber 3, the inner wall of the combustion chamber 3 is installed with a water-cooling coil 4, the top of the combustion chamber 3 is installed with a process burner 5, the interior of the furnace body 2 is located at the bottom end of the process burner 5 A quenching ring 6 is installed, the bottom end of the quenching ring 6 is fixedly connected to a downpipe 9, the outer wall of the downpipe 9 is fixedly sleeved with an uppipe 10, one side outer wall of the furnace body 2 is fixedly connected to an exhaust pipe 11, the bottom end of the furnace body 2 is fixedly connected to a drain pipe 12, the bottom end of the furnace body 2 is switched on and off by a switch mechanism 7, and the sewage in the drain pipe 12 is discharged through the drain mechanism 8.

[0027] In this embodiment: the process burner 5 is divided into three layers, the outermost layer and the center layer are both passed through oxygen, and the middle layer is passed through water-coal slurry. The oxygen atomizes the water-coal slurry and sprays it into the combustion chamber 3 for reaction. The quenching ring 6 forms a thin water film, which flows down with the synthesis gas, isolating the high-temperature synthesis gas from direct contact with the downcomer 9, protecting the downcomer 9 from deformation due to high temperature. The downcomer 9 introduces the synthesis gas into the quenching water at the bottom of the furnace body 2 for water bathing, so that the slag in the gas is reduced and solidified. The riser 10 leads the bubbling and rising synthesis gas after quenching to the upper part of the quenching water liquid surface and discharges it through the exhaust pipe 11.

[0028] Please refer to Figures 2 to 5 The switch mechanism 7 includes a fixing ring 701, which is fixedly connected to the bottom end of the furnace body 2. The inner wall of the drain pipe 12 is fixedly connected to a mounting plate 702. A limiting column 703 is fixedly connected between the fixing ring 701 and the mounting plate 702. The outer wall of the limiting column 703 is slidably connected to a blocking block 704. A horizontal plate 705 is fixedly connected to the outer wall of one side of the drain pipe 12. A motor 706 is installed on the outer wall of the horizontal plate 705. The output end of the motor 706 is connected to a first threaded rod 707. The outer wall of the first threaded rod 707 is slidably connected to a movable plate 708. The outer wall of the movable plate 708 is fixedly connected There is a tooth plate 709, which slides along the outer wall of the sewage pipe 12. The outer wall of the sewage pipe 12 is located on one side of the tooth plate 709 and is rotatably connected to the first straight gear 710. One end of the first straight gear 710 is fixedly connected to the connecting shaft 711. The outer wall of the connecting shaft 711 is located inside the mounting plate 702 and is fixedly connected to the first bevel gear 712. The inside of the mounting plate 702 is located on the outer wall of the first bevel gear 712 and is rotatably connected to the second bevel gear 713. The top of the second bevel gear 713 is fixedly connected to the second threaded rod 714, and the second threaded rod 714 extends to the inside of the blocking block 704.

[0029] In this embodiment: the operation of the motor 706 drives the first threaded rod 707 to rotate, the rotation of the first threaded rod 707 drives the movable plate 708 to displace, the displacement of the movable plate 708 drives the tooth plate 709 to displace, the tooth plate 709 moves downward and contacts the first spur gear 710, the displacement of the tooth plate 709 drives the first spur gear 710 to rotate, the rotation of the first spur gear 710 drives the connecting shaft 711 to rotate, the rotation of the connecting shaft 711 drives the first bevel gear 712 to rotate, the rotation of the first bevel gear 712 drives the second bevel gear 713 to rotate, the rotation of the second bevel gear 713 drives the blocking block 704 to displace, the blocking block 704 moves upward along the limiting column 703, the blocking block 704 displaces and contacts the fixed ring 701, and the bottom end of the furnace body 2 is closed.

[0030] Please refer to Figures 3 to 7 The sewage discharge mechanism 8 includes a baffle 801, which is rotatably connected to the inner wall of the sewage pipe 12. One end of the baffle 801 is located on the outer wall of the sewage pipe 12 and is fixedly connected to the third spur gear 802. One end of the connecting shaft 711 is fixedly connected to the fourth spur gear 803. The outer wall of the sewage pipe 12 is located on one side of the fourth spur gear 803 and is slidably connected to a vertical rod 804. The interior of the sewage pipe 12 is located at the top of the baffle 801 and is slidably connected to a positioning block 805. The positioning block 805 extends out of the sewage pipe 12, and the vertical rod 804 passes through the positioning block 805. The top of the positioning block 805 The upper and lower ends of the support frame 1 are respectively provided with a first inclined groove 806 and a second inclined groove 808. The outer wall of the vertical rod 804 is fixedly connected with a first push plate 807 and a second push plate 809. The first push plate 807 is located above the second push plate 809. The top of the support frame 1 is fixedly connected with a water tank 810. The outer wall of the water tank 810 is fixedly connected with a water outlet pipe 811. The water outlet pipe 811 is connected to the furnace body 2. The inside of the water outlet pipe 811 is slidably connected with a partition 812. A spring 813 is connected between the partition 812 and the water outlet pipe 811. The bottom end of the partition 812 is fixedly connected with a displacement rod 814.

[0031] In this embodiment: the baffle 801 closes the sewage pipe 12, and the sewage is collected above the baffle 801 and at the bottom of the furnace body 2. When part of the sewage is discharged, the motor 706 drives the gear plate 709 to move downward, and the gear plate 709 first contacts the first spur gear 710, driving the first spur gear 710 to rotate, and the blocking block 704 moves to contact the fixed ring 701, closing the bottom of the furnace body 2. At this time, the cold water above the fixed ring 701 can continue to perform the water bath operation, and at the same time, the first spur gear 710 rotates to drive the connecting shaft 711 to rotate, and the connecting shaft 711 rotates to drive the fourth spur gear 803 to rotate. The fourth spur gear 803 rotates and drives the vertical rod 804 to move. The displacement of the vertical rod 804 drives the first push plate 807 to move. The first push plate 807 moves and contacts the first inclined groove 806, pushing the positioning block 805 to move. When the tooth plate 709 separates from the first spur gear 710, the positioning block 805 separates from the baffle 801. Then the tooth plate 709 continues to move and moves and contacts the third spur gear 802, driving the third spur gear 802 to rotate. The rotation of the third spur gear 802 drives the baffle 801 to rotate, opening the sewage pipe 12, so that the sewage above the baffle 801 is discharged. After completion, the tooth plate 709 moves upward and resets, driving the baffle 801 to rotate and close the sewage pipe 12. Thereafter, the tooth plate 709 contacts the first straight gear 710, driving the first straight gear 710 to rotate and reset. The first straight gear 710 rotates and drives the vertical rod 804 to move downward and reset, opening the bottom end of the furnace body 2 so that sewage can flow into the upper part of the baffle 801 in the sewage pipe 12. At the same time, the first straight gear 710 rotates and drives the vertical rod 804 to move. The displacement of the vertical rod 804 drives the second push plate 809 to move. The second push plate 809 moves and contacts the second chute 808, pushing the positioning block 805 to move. The positioning block 805 is positioned 811 , the water in the water tank 810 can flow into the furnace body 2 through the water outlet pipe 811 to replenish the water at the bottom of the furnace body 2. After completion, the movable plate 708 moves downward and separates from the displacement rod 814, canceling the water inlet operation. The tooth plate 709 moves downward and contacts the first spur gear 710, closing the bottom of the furnace body 2. At this time, the cold water above the fixed ring 701 can continue to perform a water bath operation. Then the tooth plate 709 contacts the third spur gear 802, driving the baffle 801 to rotate to open the drain pipe 12, and the sewage above the baffle 801 is discharged through the drain pipe 12; when the tooth plate 709 is reset, the baffle 801 rotates to close the drain pipe 12, and then the bottom end of the furnace body 2 is opened, so that the sewage in the water-cooled wall gasification furnace can be discharged without stopping the machine.

[0032] Please refer to Figures 2 to 5 A first threaded hole is formed on the outer wall of the movable plate 708 , and the first threaded hole matches the first threaded rod 707 .

[0033] In this embodiment, the operation of the motor 706 drives the first threaded rod 707 to rotate, the rotation of the first threaded rod 707 drives the movable plate 708 to move, and the displacement of the movable plate 708 drives the gear plate 709 to move.

[0034] Please refer to Figures 2 to 5 The outer wall of the tooth plate 709 is provided with a tooth groove, which is engaged with the first spur gear 710 , and the first bevel gear 712 is engaged with the second bevel gear 713 .

[0035] In this embodiment: the tooth plate 709 moves downward and contacts the first spur gear 710. The displacement of the tooth plate 709 drives the first spur gear 710 to rotate. The rotation of the first spur gear 710 drives the connecting shaft 711 to rotate. The rotation of the connecting shaft 711 drives the first bevel gear 712 to rotate. The rotation of the first bevel gear 712 drives the second bevel gear 713 to rotate.

[0036] Please refer to Figures 2 to 5 A second threaded hole is provided at the bottom end of the blocking block 704, and the second threaded hole matches the second threaded rod 714. The top of the blocking block 704 is conical, and a limiting hole is provided on the outer wall of the blocking block 704, and the inner wall of the limiting hole fits with the outer wall of the limiting column 703.

[0037] In this embodiment: the rotation of the first bevel gear 712 drives the second bevel gear 713 to rotate, and the rotation of the second bevel gear 713 drives the blocking block 704 to move, and the blocking block 704 moves upward along the limiting column 703. The blocking block 704 moves and contacts the fixing ring 701, thereby closing the bottom end of the furnace body 2.

[0038] Please refer to Figures 3 to 7 The outer wall of the vertical rod 804 is provided with gear teeth, which mesh with the fourth spur gear 803.

[0039] In this embodiment, the first spur gear 710 rotates to drive the connecting shaft 711 to rotate, the connecting shaft 711 rotates to drive the fourth spur gear 803 to rotate, and the fourth spur gear 803 rotates to drive the vertical rod 804 to move.

[0040] Please refer to Figures 3 to 7 , the tooth grooves on the tooth plate 709 are meshed with the third spur gear 802.

[0041] In this embodiment, the tooth plate 709 continues to move, and the tooth plate 709 is displaced to contact the third spur gear 802, driving the third spur gear 802 to rotate. The rotation of the third spur gear 802 drives the baffle 801 to rotate, and the sewage pipe 12 is opened. Example 2

[0042] A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1: Coal slurry gasification and synthesis gas preparation The raw coal (Huainan coal, ash content 24wt%) was ground to D90 = 100μm by a vertical roller mill, mixed with 60℃ hot water at a coal:water ratio of 62:38 (mass ratio), and 0.1wt% sodium lignin sulfonate dispersant was added to prepare a water-coal slurry with a viscosity of 550cP. The water-coal slurry was mixed with pure oxygen (oxygen-coal ratio 0.8 Nm 3 / kg) is sprayed into a water-cooled wall gasifier and reacted for 4 seconds at an operating pressure of 6.5 MPa and a temperature of 1330°C to generate a crude synthesis gas containing 6.3% CO4, 44.0% H2, and 6.2% CO2.

[0043] Step 2: One-step synthesis of olefins from syngas The synthesis gas prepared in step 1 was preheated to 420°C through a plate heat exchanger, mixed with the circulating gas (H2 / CO molar ratio of 1.95) and entered the radial flow fluidized bed reactor. The reactor was heated at an operating pressure of 2.5 MPa, a temperature of 375°C, and a space velocity of 800 h -1 Under the conditions, ZnCrAlO x @SAPO-34 core-shell catalyst catalyzes the reaction to produce olefin-containing reaction gas.

[0044] Step 3: Olefin separation and light hydrocarbon recovery The reaction gas prepared in step 2 is pressurized to 3.0 MPa by a three-stage centrifugal compressor and then enters a molecular sieve adsorption tower (silicon-aluminum ratio 300:1) for dehydration to a dew point of -70°C. The dehydrated gas is then passed into an oil absorption separation tower with an operating pressure of 3.0 MPa, a pre-cutting section temperature of -25°C, and an oil absorption section temperature of -40°C. C2 light hydrocarbons with an ethane content of 95.2% are output from the top of the tower and are combined and returned to step 2 as dilution gas. A C3-C4 olefin mixture containing 45.2% propylene and 45.1% butene is output from the bottom of the tower.

[0045] Step 4: Olefin polymerization-hydrogenation integrated modification The C3-C4 olefin mixture prepared in step 3 was introduced into the upper section of the fixed bed reactor at a temperature of 175°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 Under the conditions, the oligomerization reaction was carried out on the macroporous SPA catalyst (pore size 50nm), and the product distribution was: C838.2%, C 12 52.1%, C 16 9.7% (distillation range 160-320℃); the aggregated flow directly falls to the lower hydrogenation zone, under the conditions of temperature 275℃ and pressure 6.0MPa, on NiMo / Al2O3 catalyst (pore volume 0.5cm 3 / g) was hydrogenated with hydrogen (hydrogen-to-oil volume ratio 300:1) to obtain alkane products.

[0046] Step 5: Fractionation and product cutting The hydrogenation product prepared in step 4 was heated to 380°C in a tubular heating furnace and then entered into a vacuum distillation tower (tower top pressure -0.08 MPa, tower bottom temperature 320°C) to cut the fraction: the 180-260°C fraction was light fuel oil (yield 43.3%, viscosity 5.8 mm 2 / s), 260-350℃ fraction is medium fuel oil (yield 40.2%, viscosity 14.1mm 2 / s).

[0047] The apparatus for producing fuel oil by reforming coal to olefins is the same as that in Example 1 and will not be described in detail here. Example 3

[0048] A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1: Coal slurry gasification and synthesis gas preparation The raw coal (Shaanxi coal, ash content 18wt%) was ground to D90 = 100μm by a vertical roller mill, mixed with 60℃ hot water at a coal:water ratio of 62:38 (mass ratio), and 0.1wt% sodium lignin sulfonate dispersant was added to prepare a water-coal slurry with a viscosity of 650cP. The water-coal slurry was mixed with pure oxygen (oxygen-coal ratio 0.8 Nm 3 / kg) is sprayed into a water-cooled wall gasifier and reacted for 6 seconds at an operating pressure of 6.5 MPa and a temperature of 1370°C to generate a crude synthesis gas containing 47.9% CO, 42.5% H2, and 6.3% CO2.

[0049] Step 2: One-step synthesis of olefins from syngas The synthesis gas prepared in step 1 was preheated to 420°C through a plate heat exchanger, mixed with the circulating gas (H2 / CO molar ratio of 1.95) and entered the radial flow fluidized bed reactor. The reactor was heated at an operating pressure of 2.5 MPa, a temperature of 385°C, and a space velocity of 800 h -1Under the conditions, ZnCrAlO x @SAPO-34 core-shell catalyst catalyzes the reaction to produce olefin-containing reaction gas.

[0050] Step 3: Olefin separation and light hydrocarbon recovery The reaction gas prepared in step 2 is pressurized to 3.0 MPa by a three-stage centrifugal compressor and then enters a molecular sieve adsorption tower (silicon-aluminum ratio 300:1) for dehydration to a dew point of -70°C. The dehydrated gas is then passed into an oil absorption separation tower with an operating pressure of 3.0 MPa, a pre-cutting section temperature of -25°C, and an oil absorption section temperature of -40°C. C2 light hydrocarbons with an ethane content of 96.5% are output from the top of the tower and are combined and returned to step 2 as dilution gas. A C3-C4 olefin mixture containing 38.5% propylene and 52.3% butene is output from the bottom of the tower.

[0051] Step 4: Olefin polymerization-hydrogenation integrated modification The C3-C4 olefin mixture prepared in step 3 was introduced into the upper section of the fixed bed reactor at a temperature of 185°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 Under the conditions, the oligomerization reaction was carried out on the macroporous SPA catalyst (pore size 50nm), and the product distribution was: C841.8%, C 12 48.5%, C 16 12.0% (distillation range 160-320℃); the aggregated flow directly falls to the lower hydrogenation zone, under the conditions of temperature 285℃ and pressure 6.0MPa, on NiMo / Al2O3 catalyst (pore volume 0.5cm 3 / g) was hydrogenated with hydrogen (hydrogen-to-oil volume ratio 300:1) to obtain alkane products.

[0052] Step 5: Fractionation and product cutting The hydrogenation product prepared in step 4 was heated to 380°C in a tubular heating furnace and then entered into a vacuum distillation tower (tower top pressure -0.08 MPa, tower bottom temperature 320°C) to cut the fraction: the 180-260°C fraction was light fuel oil (yield 47.8%, viscosity 4.9 mm 2 / s, cetane number 58), 260-350℃ fraction is medium fuel oil (yield 37.5%, viscosity 10.8mm 2 / s).

[0053] The apparatus for producing fuel oil by reforming coal to olefins is the same as that in Example 1 and will not be described in detail here.

[0054] Comparative Example 1 A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1: Same as Example 1; Step 2: One-step synthesis of olefins from syngas: The syngas prepared in step 1 is preheated to 420°C via a plate heat exchanger, mixed with circulating gas (H2 / CO=1.95) and fed into a radial flow fluidized bed reactor at a pressure of 2.5 MPa, a temperature of 380±5°C, and a space velocity of 800 h -1 Under these conditions, ZnCrAlO x Catalyzed with SAPO-34 physically mixed catalyst (mass ratio 1:1) to obtain olefin-containing reaction gas; Step 3 to Step 5: Same as Example 1. The device for producing fuel oil by using coal-to-olefin modification is the same as that in Example 1 and will not be described in detail here.

[0055] Comparative Example 2 A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1 to step 3: same as in Example 1; Step 4: Olefin stepwise modification: The C3-C4 olefin component prepared in step 3 is fed into the first fixed bed reactor and heated at a temperature of 180±5°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 The oligomerization was carried out under the conditions of macroporous SPA catalyst; the oligomer was cooled to 50°C and then pumped into the second fixed bed reactor, where it was catalytically saturated with hydrogenation catalyst at a temperature of 280°C ± 5°C, a pressure of 6.0 MPa, and a hydrogen-to-oil volume ratio of 300:1; Step 5: Same as Example 1. The device for producing fuel oil by using coal-to-olefin modification is the same as that in Example 1 and will not be described in detail here.

[0056] Comparative Example 3 A method for producing fuel oil by modifying coal to olefins comprises the following steps: Step 1 to step 4: same as in Example 1; Step 5: Fractionation and carbon cycle: The alkane product prepared in step 4 is heated to 380°C in a tubular heating furnace and cut into fractions in a normal pressure fractionating tower (tower top pressure 0 MPa, tower bottom temperature 380°C): the 180-260°C fraction is light fuel oil, and the 260-350°C fraction is medium fuel oil.

[0057] The apparatus for producing fuel oil by reforming coal to olefins is the same as that in Example 1 and will not be described in detail here.

[0058] Performance testing: The fuel oil products prepared in Examples 1-3 and Comparative Examples 1-3 were tested for key process indicators and product performance. The testing methods are as follows: 1. Catalyst stability test: Monitor the catalyst carbon deposition rate (GB / T 5816 standard) and activity decay rate of the fluidized bed reactor (step 2) and fixed bed reactor (step 4) under the condition of continuous operation for 72 hours; 2. Fuel oil yield test: Analyze the mass ratio of each fraction in the distillation product by gas chromatography (ASTM D2887); 3. Product performance test: Viscosity: kinematic viscosity at 40°C measured according to GB / T 265; Cetane number: light fuel oil measured according to ASTM D613; Distillation range overlap: the percentage of overlapping areas between adjacent fractions calculated using simulated distillation (ASTM D7169).

[0059] The results are shown in Table 1 below:

[0060] In summary, based on the comparative data of the Examples and Comparative Examples, the core innovation of the present invention lies in significantly improving the yield and quality of the target product, light / medium fuel oil, through an optimized catalyst combination and process design. In the Examples, the light fuel oil yield of 43.3–45.3% was significantly higher than the 38.7–41.5% of the Comparative Examples, and the medium fuel oil yield of 39.0–40.2% was also better than the 34.9–36.8% of the Control Group. Furthermore, key quality indicators such as the light oil cetane number of 56–58 were higher and the fraction overlap rate of 4.0–4.5% was significantly reduced. This present invention effectively improves product selectivity and fractionation accuracy, solving the key issues of low product yield and mixed components in traditional processes.

[0061] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for producing fuel oil by using coal-to-olefin modification, characterized in that: The following steps are involved: Step 1, coal slurry gasification and synthesis gas preparation: the raw coal after impurity removal and screening is ground into a particle size D90≤100μm by a vertical roller mill, mixed with 60℃ hot water at a mass ratio of coal:water=62:38, and 0.1% sodium lignin sulfonate dispersant is added to prepare a water-coal slurry with a viscosity of 600±50cP. The prepared water-coal slurry is mixed with pure oxygen at an oxygen-coal ratio of 0.8 Nm 3 / kg is sprayed into a water-cooled wall gasifier and reacts for 4-6 seconds at a pressure of 6.5 MPa and a temperature of 1350±20°C to generate a crude synthesis gas with a CO content of 46-48%, a H2 content of 42-44%, and a CO2 content of 5-7%; Step 2: One-step synthesis of olefins from synthesis gas: The crude synthesis gas prepared in step 1 is preheated to 420°C via a plate heat exchanger, mixed with the circulating gas at a ratio of H2 / CO=1.95, and then fed into a radial flow fluidized bed reactor at a pressure of 2.5 MPa, a temperature of 380±5°C, and a space velocity of 800 h -1 Under the conditions, ZnCrAlO X @SAPO-34 core-shell catalyst produces olefin-containing reaction gas; Step 3, olefin separation and light hydrocarbon recovery: The olefin-containing reaction gas prepared in step 2 is pressurized to 3.0 MPa by a three-stage centrifugal compressor, enters a molecular sieve adsorption tower for dehydration to a dew point of ≤-70°C, and then enters an oil absorption separation tower for separation at a tower pressure of 3.0 MPa, a pre-cutting section temperature of -25°C, and an oil absorption section temperature of -40°C; C2 light hydrocarbons with an ethane content of ≥95% are output from the top of the tower and returned to step 2 as dilution gas, and a C3-C4 olefin mixture is output from the bottom of the tower; Step 4: Olefin polymerization-hydrogenation integrated modification: The C3-C4 olefin component prepared in step 3 is fed into the upper section of the fixed bed reactor and heated at a temperature of 180±5°C, a pressure of 4.0 MPa, and a space velocity of 2.0 h -1 Under the conditions of 280℃±5℃, 6.0MPa and 300:1 hydrogen-to-oil volume ratio, the oligomers are catalyzed and saturated by the hydrogenation catalyst to obtain alkane products. Step 5, fractionation and carbon cycle: The alkane product prepared in step 4 is heated to 380°C in a tubular heating furnace and cut into fractions in a vacuum distillation tower: the 180-260°C fraction is light fuel oil, and the 260-350°C fraction is medium fuel oil.

2. The device used in the method for producing fuel oil by utilizing coal-to-olefin modification according to claim 1, characterized in that: The water-cooled wall gasification furnace described in step 1 includes a support frame (1), the outer wall of the support frame (1) is fixedly connected to a furnace body (2), a combustion chamber (3) is provided on the top of the furnace body (2), a water-cooling coil (4) is installed on the inner wall of the combustion chamber (3), a process burner (5) is installed on the top of the combustion chamber (3), a quenching ring (6) is installed at the bottom end of the process burner (5) inside the furnace body (2), the bottom end of the quenching ring (6) is fixedly connected to a downpipe (9), the outer wall of the downpipe (9) is fixedly sleeved with an uppipe (10), an outer wall of one side of the furnace body (2) is fixedly connected to an exhaust pipe (11), the bottom end of the furnace body (2) is fixedly connected to a drain pipe (12), the bottom end of the furnace body (2) is switched by a switch mechanism (7), and the sewage in the drain pipe (12) is discharged through the drain mechanism (8).

3. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 2, characterized in that: The switch mechanism (7) includes a fixing ring (701), the fixing ring (701) is fixedly connected to the bottom end of the furnace body (2), the inner wall of the sewage pipe (12) is fixedly connected to a mounting plate (702), a limiting column (703) is fixedly connected between the fixing ring (701) and the mounting plate (702), the outer wall of the limiting column (703) is slidably connected to a blocking block (704), a side outer wall of the sewage pipe (12) is fixedly connected to a transverse plate (705), the outer wall of the transverse plate (705) is installed with a motor (706), the output end of the motor (706) is connected to a first threaded rod (707), the outer wall of the first threaded rod (707) is slidably connected to a movable plate (708), the outer wall of the movable plate (708) is fixedly connected A tooth plate (709) is connected, and the tooth plate (709) slides along the outer wall of the sewage pipe (12). The outer wall of the sewage pipe (12) is located on one side of the tooth plate (709) and is rotatably connected to a first spur gear (710). One end of the first spur gear (710) is fixedly connected to a connecting shaft (711). The outer wall of the connecting shaft (711) is located inside the mounting plate (702) and is fixedly connected to a first bevel gear (712). The inner part of the mounting plate (702) is located on the outer wall of the first bevel gear (712) and is rotatably connected to a second bevel gear (713). The top end of the second bevel gear (713) is fixedly connected to a second threaded rod (714), and the second threaded rod (714) extends to the interior of the blocking block (704).

4. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 3, characterized in that: The sewage discharge mechanism (8) includes a baffle (801), the baffle (801) is rotatably connected to the inner wall of the sewage discharge pipe (12), one end of the baffle (801) is located on the outer wall of the sewage discharge pipe (12) and is fixedly connected to a third spur gear (802), one end of the connecting shaft (711) is fixedly connected to a fourth spur gear (803), the outer wall of the sewage discharge pipe (12) is located on one side of the fourth spur gear (803) and is slidably connected to a vertical rod (804), the interior of the sewage discharge pipe (12) is located at the top end of the baffle (801) and is slidably connected to a positioning block (805), the positioning block (805) extends out of the sewage discharge pipe (12), the vertical rod (804) passes through the positioning block (805), and the positioning block (80 5), a first inclined groove (806) and a second inclined groove (808) are respectively provided at the top and bottom ends of the vertical rod (804), a first push plate (807) and a second push plate (809) are fixedly connected to the outer wall of the vertical rod (804), the first push plate (807) is located above the second push plate (809), the top end of the support frame (1) is fixedly connected to a water tank (810), the outer wall of the water tank (810) is fixedly connected to a water outlet pipe (811), the water outlet pipe (811) is connected to the furnace body (2), the interior of the water outlet pipe (811) is slidably connected to a partition (812), a spring (813) is connected between the partition (812) and the water outlet pipe (811), and the bottom end of the partition (812) is fixedly connected to a displacement rod (814).

5. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 3, characterized in that: A first threaded hole is formed on the outer wall of the movable plate (708), and the first threaded hole matches the first threaded rod (707).

6. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 4, characterized in that: The outer wall of the tooth plate (709) is provided with a tooth groove, the tooth groove is engaged with the first spur gear (710), and the first bevel gear (712) is engaged with the second bevel gear (713).

7. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 3, characterized in that: A second threaded hole is provided at the bottom end of the blocking block (704), and the second threaded hole matches the second threaded rod (714).

8. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 3, characterized in that: The top end of the blocking block (704) is conical, and a limiting hole is provided on the outer wall of the blocking block (704), wherein the inner wall of the limiting hole fits in contact with the outer wall of the limiting column (703).

9. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 4, characterized in that: The outer wall of the vertical rod (804) is provided with gear teeth, and the gear teeth are engaged with the fourth spur gear (803).

10. The device for producing fuel oil by utilizing coal-to-olefin modification according to claim 6, characterized in that: The tooth grooves on the tooth plate (709) are meshed with the third spur gear (802).

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