A sulfur liquid under granulation system and a sulfur liquid under granulation method

Abstract

This invention discloses a liquid sulfur granulation system and a liquid sulfur granulation method. The liquid sulfur granulation system includes a liquid sulfur pump (1), a sulfur feeding device (2), a sulfur forming facility (3), a vibrating screen (4), and a pre-crystallization facility (16), the pre-crystallization facility (16) having a pre-crystallization chamber. The liquid sulfur granulation method involves mixing fine sulfur powder separated by the vibrating screen (4) with liquid sulfur from the liquid sulfur pump (1) in the pre-crystallization chamber of the pre-crystallization facility (16). The fine sulfur powder acts as a seed crystal, inducing the liquid sulfur to pre-crystallize and form pre-crystallized crystal nuclei. The liquid sulfur containing the pre-crystallized crystal nuclei undergoes heat exchange with cooling water in the sulfur forming facility (3), cooling and forming into solid sulfur particles. This invention can be used for liquid sulfur granulation.

Description

Technical Field

[0001] This invention belongs to the field of sulfur granulation technology, and relates to a sulfur liquid granulation system and a sulfur liquid granulation method. Background Technology

[0002] In oil refineries and natural gas purification plants, large-scale sulfur granulation processes can employ submerged sulfur granulation. Liquid sulfur is pumped into a sulfur feeding device at the top of the sulfur forming facility. The liquid sulfur flows through small holes at the bottom of the feeding device into the sulfur forming facility, which is filled with cooling water. There, it exchanges heat with the water and cools, forming solid sulfur granules. These granules are then dehydrated by a vibrating screen, sieved to obtain finished sulfur granules, and fed into a finished sulfur granule hopper. From there, they enter the packaging machine's hopper.

[0003] In existing sulfur granulation systems, fine sulfur particles separated by vibrating screens that do not meet the required particle size are mainly handled in two ways: (1) The separated fine sulfur particles are collected in the open air and manually transferred out of the sulfur granulation system for further processing after a certain amount has been accumulated. This method increases the workload of manual operation and causes sulfur dust pollution, which harms the physical and mental health of on-site operators. For the above reasons, this method has been almost eliminated. (2) The commonly used method is that the fine sulfur particles separated by the vibrating screen are introduced into the melting tank by a screw conveyor and then transported to the sulfur feeding device and sulfur forming facility for secondary forming. This method recovers the fine sulfur particles and avoids sulfur dust pollution, but it has the following problems: ① The energy consumption of the melting tank is high, which makes the energy utilization efficiency of the sulfur granulation system low. ② The sulfur on the agitator blades of the melting tank is prone to clumping, causing blockage of the melting tank. ③ The finished sulfur particles after secondary forming have high moisture content, are of different sizes, and have low forming rate and regularity. ④ The cooling water consumption of the melting tank is large. Summary of the Invention

[0004] The purpose of this invention is to provide a sulfur submerged granulation system and a sulfur submerged granulation method to solve the problems of high energy consumption of the melting tank and easy agglomeration of sulfur on the impeller blades of the melting tank in existing sulfur submerged granulation technologies.

[0005] To solve the above problems, the technical solution adopted by the present invention is: a liquid sulfur granulation system, which includes a liquid sulfur pump, a sulfur feeding device, a sulfur forming facility, and a vibrating screen. The feature is that the liquid sulfur granulation system also includes a pre-crystallization facility, which has a pre-crystallization chamber. The pre-crystallization chamber is used to mix the fine sulfur powder separated by the vibrating screen with the liquid sulfur from the liquid sulfur pump, so that the liquid sulfur undergoes pre-crystallization.

[0006] A further feature of the sulfur submerged granulation system of the present invention is that: the sulfur submerged granulation system is provided with a liquid sulfur heat exchanger, which is located between the liquid sulfur pump and the pre-crystallization facility.

[0007] A further feature of the sulfur liquid granulation system of the present invention is that the sulfur liquid granulation system is provided with a fine sulfur powder hopper, a sedimentation separation tank and a hot air dryer, and the fine sulfur powder hopper, sedimentation separation tank and hot air dryer are located between the vibrating screen and the pre-crystallization facility.

[0008] A further feature of the sulfur liquid granulation system of the present invention is that: the sulfur liquid granulation system is provided with a conveyor and a conveying pipeline, the conveyor and the conveying pipeline are located between the hot air dryer and the pre-crystallization facility, and the outlet of the conveying pipeline is connected to the pre-crystallization chamber of the pre-crystallization facility.

[0009] A further feature of the sulfur liquid granulation system of the present invention is that: the sulfur liquid granulation system is provided with a sulfur granule finished product hopper, a packaging machine silo, a liquid sulfur pump, a liquid sulfur heat exchanger, a pre-crystallization facility, a sulfur feeding device, a sulfur forming facility, a vibrating screen, a sulfur granule finished product hopper, and a packaging machine silo arranged in sequence; starting from the vibrating screen, a fine powder sulfur hopper, a sedimentation separation tank, a hot air dryer, a conveyor, and a conveying pipeline are arranged in sequence.

[0010] A further feature of the sulfur liquid granulation system of the present invention is that: a regulating bypass is provided in parallel with the liquid sulfur heat exchanger and the pre-crystallization facility, the inlet of the regulating bypass is connected to the outlet of the liquid sulfur pump, and the outlet of the regulating bypass is connected to the inlet of the sulfur feeding device.

[0011] A further feature of the sulfur liquid granulation system of the present invention is that: the vibrating screen is a micro-positive pressure inertized closed vibrating screen, and the conveyor is a screw conveyor or a belt conveyor, the motor speed of which can be frequency-controlled.

[0012] A further feature of the sulfur liquid granulation system of the present invention is that: the pre-crystallization facility is provided with an inner cylinder, an outer cylinder, a nozzle, and a discharge pipe. The inner cavity of the inner cylinder is a pre-crystallization chamber. The top of the inner cylinder and the outer cylinder are provided with a top plate. The bottom of the inner cylinder is provided with an inner cylinder bottom plate. The bottom of the outer cylinder is provided with an outer cylinder bottom plate. The nozzle and the discharge pipe pass through the sides of the inner cylinder and the outer cylinder. The bottom plates of the inner cylinder and the outer cylinder are provided with a feed pipe. The feed pipe, the nozzle, and the discharge pipe are all connected to the pre-crystallization chamber. The annular space between the inner cylinder and the outer cylinder and the space between the bottom plates of the inner cylinder and the outer cylinder form a cooling water chamber.

[0013] A further feature of the sulfur liquid granulation system of the present invention is that the outlet of the conveying pipeline is directly connected to the pre-crystallization chamber through the top plate.

[0014] A further feature of the sulfur liquid granulation system of the present invention is that: a herringbone pipe is provided at the outlet of the conveying pipe, the herringbone pipe includes two pipes, the outlets of the two pipes are connected to the pre-crystallization chamber through the top plate, and a rotary valve is provided on each pipe.

[0015] A further feature of the sulfur liquid granulation system of the present invention is that: the nozzles are arranged tangentially along the inner cylinder, the nozzles are arranged in 1 to 3 layers in the vertical direction, each layer of nozzles is arranged with 1 to 4 nozzles, the nozzles are arranged inclined upward from the inlet to the outlet, the included angle between them and the horizontal plane is 30 to 60 degrees, the inner diameter of the inner cylinder is 1.2 to 2 meters, and the height of the inner cylinder is 1 to 4.6 meters.

[0016] The method for liquid sulfur granulation of the present invention is characterized in that: fine sulfur powder separated by a vibrating screen is mixed with liquid sulfur from a liquid sulfur pump in a pre-crystallization chamber of a pre-crystallization facility, the fine sulfur powder serves as a seed crystal to induce liquid sulfur pre-crystallization and form pre-crystallized crystal nuclei, and the liquid sulfur containing the pre-crystallized crystal nuclei undergoes heat exchange with cooling water in a sulfur forming facility and is cooled and formed into solid sulfur granules.

[0017] A further feature of the liquid sulfur granulation method of the present invention is that: the liquid sulfur pump sends liquid sulfur into the liquid sulfur heat exchanger, and the liquid sulfur exchanges heat with the cooling medium in the liquid sulfur heat exchanger and then enters the pre-crystallization chamber of the pre-crystallization facility.

[0018] A further feature of the liquid sulfur granulation method of the present invention is that: the fine sulfur powder separated by the vibrating screen enters the fine sulfur powder hopper, and then enters the sedimentation separation tank to separate the fine sulfur powder from water. After being separated from water, the fine sulfur powder enters the hot air dryer for drying, and is then sent by the conveyor through the conveying pipeline to the pre-crystallization chamber of the pre-crystallization facility.

[0019] A further feature of the sulfur liquid granulation method of the present invention is that: during the pre-crystallization process, cooling water is used to remove the heat of pre-crystallization.

[0020] A further feature of the liquid sulfur granulation method of the present invention is that fine powder sulfur is fed into the pre-crystallization chamber intermittently or continuously, so that the pre-crystallization process of liquid sulfur is carried out intermittently or continuously.

[0021] A further feature of the sulfur liquid granulation method of the present invention is that the pre-crystallization temperature in the pre-crystallization chamber is 110-120°C.

[0022] A further feature of the liquid sulfur granulation method of the present invention is that the particle size of the fine sulfur powder is less than 2 mm, and the mass of the fine sulfur powder entering the pre-crystallization chamber is 5% to 10% of the mass of the liquid sulfur entering the pre-crystallization chamber.

[0023] A further feature of the liquid sulfur granulation method of the present invention is that: a liquid sulfur pump sends a portion of the liquid sulfur into a liquid sulfur heat exchanger, and sends another portion of the liquid sulfur into a sulfur feeding device via a regulating bypass.

[0024] A further feature of the sulfur liquid granulation method of the present invention is that: using a pre-crystallization facility proposed in the present invention, liquid sulfur enters the pre-crystallization chamber from the nozzle and the feed pipe respectively; the conveyor lifts the fine powder sulfur into the conveying pipe above the top inlet of the herringbone pipe; the fine powder sulfur then flows by gravity through the two pipes of the herringbone pipe into the pre-crystallization chamber; by adjusting the rotary valves on the two pipes of the herringbone pipe, the flow rate of the fine powder sulfur entering the pre-crystallization chamber is adjusted; the rotary valves are opened intermittently or continuously, so that the fine powder sulfur enters the pre-crystallization chamber intermittently or continuously, thereby controlling the pre-crystallization process to proceed intermittently or continuously.

[0025] A further feature of the sulfur liquid granulation method of the present invention is that, during the pre-crystallization process, the cooling water in the cooling water chamber of the pre-crystallization facility carries away the heat of pre-crystallization.

[0026] A further feature of the liquid sulfur granulation method of the present invention is that when liquid sulfur overflows in the pre-crystallization chamber, it overflows from the overflow pipe and then enters the feed pipe.

[0027] The present invention has the following beneficial effects: (1) The present invention eliminates the melting tank, and the fine sulfur powder does not enter the melting tank for melting, which reduces the system energy consumption and improves the system energy utilization efficiency. It fundamentally solves the problem of sulfur easily agglomerating on the impeller blades of the melting tank, causing blockage of the melting tank, as well as the problem of large cooling water consumption of the melting tank. The energy consumption and cooling water consumption of the pre-crystallization facility used in the present invention are lower than those of the melting tank. (2) In the pre-crystallization chamber, the fine sulfur powder acts as a seed crystal to induce liquid sulfur pre-crystallization and form pre-crystallization nuclei. Liquid sulfur containing a certain amount of pre-crystallization nuclei is formed in the sulfur forming facility, which can largely solve the problem of uneven size and low regularity of sulfur particles prepared by the liquid sulfur granulation system. The present invention makes full use of the fine sulfur powder with unqualified particle size separated by the vibrating screen, which can increase the forming rate of sulfur particles prepared by the existing liquid sulfur granulation system by 5% to 10%. The molding rate mentioned in this invention refers to the ratio of the mass of the finished sulfur granules that meet the particle size requirements to the mass of the liquid sulfur output by the liquid sulfur pump. The regularity refers to the proportion (mass ratio) of the finished sulfur granules with a particle size of Ф3~Ф4 mm to the finished sulfur granules with a particle size of Ф2~Ф6 mm. (3) Liquid sulfur containing pre-crystallized nuclei can crystallize rapidly in the sulfur molding facility, which can effectively avoid the intercrystalline water inclusion defect that exists when liquid sulfur without pre-crystallization is molded in the sulfur molding facility in one step. Especially in the rainy and humid environment of the south, the finished sulfur granules produced by the method of this invention can not only meet the national standard requirement of 2% (percentage by mass) moisture content, but also fully meet the requirement of 0.5% moisture content for food-grade sulfur. (4) The recycling of fine sulfur powder also solves the problem of sulfur dust pollution, reduces the risk of sulfur dust explosion, and improves the working environment of on-site operators. (5) The sulfur granules produced by the present invention are spherical and the particle size (diameter) range can reach Ф2~Ф6 mm, of which sulfur granules with a particle size of Ф3~Ф4 mm account for at least 95% (the percentage is by mass).

[0028] This invention can be used for liquid sulfur granulation.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The accompanying drawings and specific embodiments do not limit the scope of protection claimed by the present invention. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an existing liquid sulfur granulation system.

[0031] Figure 2 This is a schematic diagram of the sulfur liquid granulation system of the present invention.

[0032] Figure 3 This is a schematic diagram of the structure of a pre-crystallization facility used in this invention.

[0033] Figure 4 yes Figure 3 Sectional view A-A in the diagram.

[0034] Figures 1 to 4 In this drawing, the same reference numerals indicate the same technical features. Reference numerals indicate: 1—liquid sulfur pump; 2—sulfur feeding device; 3—sulfur forming facility; 4—vibrating screen; 5—sulfur granule finished product hopper; 6—packaging machine hopper; 7—fine powder sulfur hopper; 8—melting tank; 9—rotary pump; 10—sedimentation separation tank; 11—hot air dryer; 12—conveyor; 13—conveyor pipeline; 14—regulating bypass; 15—liquid sulfur heat exchanger; 16—pre-crystallization facility; 17—inner cylinder; 18—outer cylinder; 19—top plate; 20—outer cylinder bottom plate; 21—herringbone pipe; 22—rotary valve; 23—overflow pipe; 24—feed pipe; 25—nozzle; 26—discharge pipe; 27—inner cylinder bottom plate; 28—cooling water inlet pipe; 29—cooling water outlet pipe. Detailed Implementation

[0035] See Figure 1 An existing liquid sulfur granulation system comprises, in sequence, a liquid sulfur pump 1, a sulfur feeding device 2, a sulfur forming facility 3, a vibrating screen 4, a finished sulfur granule hopper 5, and a packaging machine hopper 6. Starting from the vibrating screen 4, a fine sulfur powder hopper 7, a melting tank 8, and a rotor pump 9 are arranged sequentially. The outlet of the rotor pump 9 is connected to the inlet of the sulfur feeding device 2. During system operation, the fine sulfur powder separated by the vibrating screen 4 first enters the fine sulfur powder hopper 7, then enters the melting tank 8 for melting. After melting in the melting tank 8, it is directly sent by the rotor pump 9 to the sulfur feeding device 2, and then enters the sulfur forming facility 3 for secondary forming, cooling and solidifying into sulfur granules. The sulfur granules are then dehydrated and sieved through the vibrating screen 4 to obtain finished sulfur granules, which enter the finished sulfur granule hopper 5, and then from the finished sulfur granule hopper 5 into the packaging machine hopper 6.

[0036] See Figure 2 The sulfur liquid granulation system of the present invention (hereinafter referred to as the system) is provided in sequence with a liquid sulfur pump 1, a liquid sulfur heat exchanger 15, a pre-crystallization facility 16, a sulfur feeding device 2, a sulfur forming facility 3, a vibrating screen 4, a sulfur granule finished product hopper 5, and a packaging machine hopper 6. Starting from the vibrating screen 4, a fine powder sulfur hopper 7, a sedimentation separation tank 10, a hot air dryer 11, a conveyor 12, and a conveying pipeline 13 are provided in sequence. The outlet of the conveying pipeline 13 is connected to the pre-crystallization chamber of the pre-crystallization facility 16.

[0037] Except for the pre-crystallization facility 16, all other facilities in this invention's system can use facilities commonly used in the field. In a preferred embodiment, the vibrating screen 4 is a slightly positive pressure inertized closed vibrating screen. The conveyor 12 is a screw conveyor or belt conveyor, and its motor speed can be frequency-controlled to adjust the processing volume of fine sulfur powder, flexibly adjusting the regularity of the sulfur granules produced by the sulfur liquid granulation system, making operation simple and convenient.

[0038] Figure 3 and Figure 4 The pre-crystallization facility 16 used in this invention is shown, comprising an inner cylinder 17, an outer cylinder 18, a nozzle 25, and a discharge pipe 26. Both the inner cylinder 17 and the outer cylinder 18 are cylindrical and coaxially arranged, with the inner cavity of the inner cylinder 17 serving as a pre-crystallization chamber. A top plate 19 is provided at the top of both the inner cylinder 17 and the outer cylinder 18, and an inner cylinder bottom plate 27 and an outer cylinder bottom plate 20 are provided at the bottom of the outer cylinder 18. The nozzle 25 and the discharge pipe 26 pass through the sides of the inner cylinder 17 and the outer cylinder 18. A feed pipe 24 is provided on the inner cylinder bottom plate 27 and the outer cylinder bottom plate 20, passing through them. An overflow pipe 23 is provided on the top plate 19. The feed pipe 24, nozzle 25, discharge pipe 26, and overflow pipe 23 are all connected to the pre-crystallization chamber. The annular space between the inner cylinder 17 and the outer cylinder 18, and the space between the inner cylinder bottom plate 27 and the outer cylinder bottom plate 20, form a cooling water chamber for holding cooling water. The outer cylinder 18 is provided with a cooling water inlet pipe 28 and a cooling water outlet pipe 29, both of which communicate with the cooling water chamber.

[0039] The outlet of the conveying pipe 13 is provided with a herringbone pipe 21, which includes two pipes. The outlets of the two pipes are connected to the pre-crystallization chamber through the top plate 19. Each pipe is equipped with a rotary valve 22. Alternatively, the outlet of the conveying pipe 13 may not have a herringbone pipe 21 and may be directly connected to the pre-crystallization chamber through the top plate 19.

[0040] The nozzle 25 and feed pipe 24 supply liquid sulfur into the pre-crystallization chamber, the conveying pipe 13 and herringbone pipe 21 supply fine powder sulfur into the pre-crystallization chamber, the discharge pipe 26 supplies liquid sulfur containing pre-crystallized crystal nuclei to flow out of the pre-crystallization chamber, and the overflow pipe 23 supplies liquid sulfur to overflow from the pre-crystallization chamber.

[0041] Figure 3 and Figure 4A preferred embodiment of the pre-crystallization facility 16 is that the nozzles 25 are arranged tangentially to the inner cylinder 17. The nozzles 25 are generally arranged in 1 to 3 layers vertically, with 1 to 4 nozzles 25 in each layer. When multiple nozzles 25 are arranged in each layer, they are evenly distributed around the circumference of the inner cylinder 17. The nozzles 25 are inclined upwards from the inlet to the outlet, with an angle of 30 to 60 degrees to the horizontal plane. The liquid sulfur ejected from each nozzle 25 rotates in the same direction within the pre-crystallization chamber. The inner diameter of the inner cylinder 17 is generally 1.2 to 2 meters, and the height of the inner cylinder 17 is generally 1 to 4.6 meters.

[0042] Using the present invention Figure 2 The method for liquid sulfur granulation in the system shown is as follows: Liquid sulfur pump 1 sends liquid sulfur into liquid sulfur heat exchanger 15. The liquid sulfur is cooled by heat exchange with the cooling medium in liquid sulfur heat exchanger 15 and then enters the pre-crystallization chamber of pre-crystallization facility 16. In the pre-crystallization chamber, the liquid sulfur mixes with fine sulfur powder, which acts as seed crystals to induce pre-crystallization and form pre-crystallized crystal nuclei. The liquid sulfur containing the pre-crystallized crystal nuclei flows out of pre-crystallization facility 16 and enters the sulfur feeding device 2 at the top of sulfur forming facility 3. The liquid sulfur then flows through a small hole at the bottom of sulfur feeding device 2 into sulfur forming facility 3 filled with cooling water, where it exchanges heat with the cooling water and cools to form solid sulfur granules. The solid sulfur granules then enter vibrating screen 4, where they are dehydrated and sieved to obtain finished sulfur granules. The finished sulfur granules enter sulfur granule hopper 5, and then from sulfur granule hopper 5 into packaging machine hopper 6.

[0043] Fine sulfur powder that fails to meet particle size requirements (below the specifications for finished sulfur granules) after dehydration and sieving by vibrating screen 4 enters fine sulfur powder hopper 7, and then enters sedimentation separator 10 for separation of fine sulfur powder from water. After separation from water, the fine sulfur powder enters hot air dryer 11 for drying, and is then conveyed by conveyor 12 through conveying pipe 13 into the pre-crystallization chamber of pre-crystallization facility 16 to mix with liquid sulfur. The fine sulfur powder acts as seed crystals, inducing pre-crystallization of liquid sulfur and forming pre-crystallization nuclei. Liquid sulfur containing pre-crystallization nuclei flows out of pre-crystallization facility 16 and enters sulfur feeding device 2.

[0044] During the pre-crystallization process, circulating cooling water can be used to remove the heat from pre-crystallization and maintain the pre-crystallization temperature within the pre-crystallization chamber. The pre-crystallization temperature within the chamber is generally 110–120°C. The specific pre-crystallization temperature and time are adjusted and ultimately determined based on the required moisture content of the finished sulfur granules and the temperature field distribution curve within the pre-crystallization chamber.

[0045] Depending on the process requirements, fine sulfur powder, which serves as a seed crystal, can be introduced into the pre-crystallization chamber intermittently or continuously, so that the pre-crystallization process of liquid sulfur can be carried out intermittently or continuously.

[0046] The particle size of fine sulfur powder is generally less than 2 mm. The particle size of fine sulfur powder described in this invention is the equivalent diameter of an equal-volume sphere. The mass of fine sulfur powder entering the pre-crystallization chamber is generally 5% to 10% of the mass of liquid sulfur entering the pre-crystallization chamber.

[0047] This invention can be equipped with a regulating bypass 14 connected in parallel with the liquid sulfur heat exchanger 15 and the pre-crystallization facility 16. The regulating bypass 14 is a single pipe. The inlet of the regulating bypass 14 is connected to the outlet of the liquid sulfur pump 1, and the outlet of the regulating bypass 14 is connected to the inlet of the sulfur feeding device 2. During system operation, the liquid sulfur pump 1 sends a portion of the liquid sulfur into the liquid sulfur heat exchanger 15, and sends the remaining portion of the liquid sulfur into the sulfur feeding device 2 via the regulating bypass 14.

[0048] When using this invention Figure 3 and Figure 4 In the pre-crystallization facility 16 shown, liquid sulfur flows out of the liquid sulfur heat exchanger 15 and enters the pre-crystallization chamber through pipes via nozzle 25 and feed pipe 24. Conveyor 12 lifts fine sulfur powder into conveying pipe 13 above the top inlet of herringbone pipe 21. The fine sulfur powder then flows by gravity through the two pipes of herringbone pipe 21 into the pre-crystallization chamber. The flow rate of fine sulfur powder entering the pre-crystallization chamber can be adjusted by regulating the rotary valve 22 on the two pipes of herringbone pipe 21. Depending on process requirements, the rotary valve 22 can be opened intermittently or continuously to allow the fine sulfur powder to enter the pre-crystallization chamber intermittently or continuously, controlling the pre-crystallization process to proceed intermittently or continuously. The fine sulfur powder entering the pre-crystallization chamber through the two pipes of herringbone pipe 21 can be distributed relatively evenly in the liquid sulfur.

[0049] The intermittent or continuous opening of the rotary valve 22, and the frequency conversion adjustment of the motor speed of the screw conveyor or belt conveyor, can improve the control accuracy of the flow rate of fine sulfur entering the pre-crystallization chamber, increase the flexibility of adjustment, reduce operating costs and energy consumption, improve productivity, and ensure the reliability of continuous and safe operation of the sulfur liquid granulation system.

[0050] Figure 3 and Figure 4 In the pre-crystallization facility 16 shown, after liquid sulfur pre-crystallizes in the pre-crystallization chamber, the liquid sulfur containing pre-crystallized crystal nuclei flows out from the discharge pipe 26 and enters the sulfur feeding device 2. When liquid sulfur overflows in the pre-crystallization chamber, it overflows from the overflow pipe 23 and then enters the feed pipe 24 through a pipeline. During the pre-crystallization process, cooling water enters the cooling water chamber of the pre-crystallization facility 16 from the cooling water inlet pipe 28, and the cooling water in the cooling water chamber flows out from the cooling water outlet pipe 29. The cooling water in the cooling water chamber flows continuously, carrying away the heat of pre-crystallization.

[0051] Figure 3 and Figure 4The pre-crystallization capacity of the pre-crystallization facility 16 shown is generally 1 to 30 tons / hour. The pre-crystallization capacity refers to the total weight of liquid sulfur and fine sulfur powder entering the pre-crystallization chamber per hour.

[0052] This invention is not limited to the use of Figure 3 and Figure 4 The pre-crystallization facility 16 shown can also be used with other pre-crystallization facilities of the same structure.

Claims

1. A liquid sulfur granulation system, comprising a liquid sulfur pump (1), a sulfur feeding device (2), a sulfur forming facility (3), and a vibrating screen (4), characterized in that: The liquid sulfur granulation system is also equipped with a pre-crystallization facility (16), which has a pre-crystallization chamber. The pre-crystallization chamber is used to mix the fine sulfur powder separated by the vibrating screen (4) with the liquid sulfur from the liquid sulfur pump (1), and the liquid sulfur undergoes pre-crystallization. The vibrating screen (4) is a micro-positive pressure inertized closed vibrating screen; The pre-crystallization facility (16) is provided with an inner cylinder (17), an outer cylinder (18), a nozzle (25), and a discharge pipe (26). The inner cavity of the inner cylinder (17) is a pre-crystallization chamber. The top of the inner cylinder (17) and the outer cylinder (18) are provided with a top plate (19). The bottom of the inner cylinder (17) is provided with an inner cylinder bottom plate (27). The bottom of the outer cylinder (18) is provided with an outer cylinder bottom plate (20). The nozzle (25) and the discharge pipe (26) pass through the sides of the inner cylinder (17) and the outer cylinder (18). The inner cylinder bottom plate (27) and the outer cylinder bottom plate (20) are provided with a feed pipe (24). The feed pipe (24), the nozzle (25), and the discharge pipe (26) are all connected to the pre-crystallization chamber. The annular space between the inner cylinder (17) and the outer cylinder (18) and the space between the inner cylinder bottom plate (27) and the outer cylinder bottom plate (20) form a cooling water chamber.

2. The sulfur liquid granulation system according to claim 1, characterized in that: The liquid sulfur granulation system is equipped with a liquid sulfur heat exchanger (15), which is located between the liquid sulfur pump (1) and the pre-crystallization facility (16).

3. The sulfur liquid granulation system according to claim 2, characterized in that: The sulfur liquid granulation system is equipped with a fine sulfur hopper (7), a sedimentation separation tank (10) and a hot air dryer (11), which are located between the vibrating screen (4) and the pre-crystallization facility (16).

4. The sulfur liquid granulation system according to claim 3, characterized in that: The sulfur liquid granulation system is equipped with a conveyor (12) and a conveying pipe (13). The conveyor (12) and the conveying pipe (13) are located between the hot air dryer (11) and the pre-crystallization facility (16). The outlet of the conveying pipe (13) is connected to the pre-crystallization chamber of the pre-crystallization facility (16).

5. The sulfur liquid granulation system according to claim 4, characterized in that: The sulfur liquid granulation system is equipped with a sulfur granule finished product hopper (5), a packaging machine hopper (6), a liquid sulfur pump (1), a liquid sulfur heat exchanger (15), a pre-crystallization facility (16), a sulfur feeding device (2), a sulfur forming facility (3), a vibrating screen (4), a sulfur granule finished product hopper (5), and a packaging machine hopper (6) arranged in sequence. Starting from the vibrating screen (4), a fine powder sulfur hopper (7), a sedimentation separation tank (10), a hot air dryer (11), a conveyor (12), and a conveying pipeline (13) are arranged in sequence.

6. The sulfur liquid granulation system according to claim 5, characterized in that: A regulating bypass (14) is connected in parallel with the liquid sulfur heat exchanger (15) and the pre-crystallization facility (16). The inlet of the regulating bypass (14) is connected to the outlet of the liquid sulfur pump (1), and the outlet of the regulating bypass (14) is connected to the inlet of the sulfur feeder (2).

7. The sulfur liquid granulation system according to claim 6, characterized in that: The conveyor (12) is a screw conveyor or a belt conveyor, and the motor speed of the conveyor is frequency-controlled.

8. The sulfur liquid granulation system according to claim 7, characterized in that: The outlet of the conveying pipe (13) is directly connected to the pre-crystallization chamber through the top plate (19).

9. The sulfur liquid granulation system according to claim 7, characterized in that: The outlet of the conveying pipe (13) is provided with a herringbone pipe (21), which includes two pipes. The outlets of the two pipes are connected to the pre-crystallization chamber through the top plate (19). Each pipe is equipped with a rotary valve (22).

10. The sulfur liquid granulation system according to claim 7, characterized in that: The nozzles (25) are arranged tangentially along the inner cylinder (17). There are 1 to 3 layers of nozzles (25) arranged vertically. Each layer of nozzles (25) has 1 to 4 nozzles (25). The nozzles (25) are arranged inclined upward from the inlet to the outlet, with an angle of 30 to 60 degrees between them and the horizontal plane. The inner diameter of the inner cylinder (17) is 1.2 to 2 meters, and the height of the inner cylinder (17) is 1 to 4.6 meters.

11. A method for granulating sulfur under liquid granulation system according to claim 1, characterized in that: The fine sulfur powder separated by the vibrating screen (4) is mixed with the liquid sulfur from the liquid sulfur pump (1) in the pre-crystallization chamber of the pre-crystallization facility (16). The fine sulfur powder serves as a seed crystal, inducing the liquid sulfur to pre-crystallize and form pre-crystallized crystal nuclei. The liquid sulfur containing the pre-crystallized crystal nuclei undergoes heat exchange with cooling water in the sulfur forming facility (3) and is cooled and formed into solid sulfur particles.

12. The method for liquid granulation of sulfur according to claim 11, characterized in that: The liquid sulfur pump (1) sends liquid sulfur into the liquid sulfur heat exchanger (15). After the liquid sulfur is cooled down by exchanging heat with the cooling medium in the liquid sulfur heat exchanger (15), it enters the pre-crystallization chamber of the pre-crystallization facility (16).

13. The method for liquid granulation of sulfur according to claim 12, characterized in that: The fine sulfur powder separated by the vibrating screen (4) enters the fine sulfur powder hopper (7), and then enters the sedimentation separation tank (10) to separate the fine sulfur powder from water. After being separated from water, the fine sulfur powder enters the hot air dryer (11) for drying, and is then sent by the conveyor (12) through the conveying pipeline (13) into the pre-crystallization chamber of the pre-crystallization facility (16).

14. The method for liquid granulation of sulfur according to claim 13, characterized in that: During the pre-crystallization process, cooling water is used to remove the heat of pre-crystallization.

15. The method for liquid granulation of sulfur according to claim 11 or 14, characterized in that: Fine sulfur powder is fed into the pre-crystallization chamber intermittently or continuously, so that the pre-crystallization process of liquid sulfur can be carried out intermittently or continuously.

16. The method for liquid granulation of sulfur according to claim 15, characterized in that: The pre-crystallization temperature in the pre-crystallization chamber is 110–120℃.

17. The method for liquid granulation of sulfur according to claim 16, characterized in that: The particle size of fine sulfur powder is less than 2 mm, and the mass of fine sulfur powder entering the pre-crystallization chamber is 5% to 10% of the mass of liquid sulfur entering the pre-crystallization chamber.

18. The method for liquid granulation of sulfur according to claim 17, characterized in that: The liquid sulfur pump (1) sends a portion of the liquid sulfur into the liquid sulfur heat exchanger (15) and sends another portion of the liquid sulfur into the sulfur feeding device (2) via the regulating bypass (14).

19. The method for liquid granulation of sulfur according to claim 11, characterized in that: Using the pre-crystallization facility (16) as described in claim 11, liquid sulfur enters the pre-crystallization chamber from the nozzle (25) and the feed pipe (24), respectively. The conveyor (12) lifts the fine sulfur powder into the conveying pipe (13) above the top inlet of the herringbone pipe (21). The fine sulfur powder then flows through the two pipes of the herringbone pipe (21) to the pre-crystallization chamber. By adjusting the rotary valve (22) on the two pipes of the herringbone pipe (21), the flow rate of the fine sulfur powder entering the pre-crystallization chamber is adjusted. The rotary valve (22) is opened intermittently or continuously to allow the fine sulfur powder to enter the pre-crystallization chamber intermittently or continuously, thereby controlling the pre-crystallization process to proceed intermittently or continuously.

20. The method for liquid granulation of sulfur according to claim 19, characterized in that: During the pre-crystallization process, the cooling water in the cooling water chamber of the pre-crystallization facility (16) carries away the pre-crystallization heat.

21. The method for liquid granulation of sulfur according to claim 20, characterized in that: When liquid sulfur overflows from the pre-crystallization chamber, it overflows from the overflow pipe (23) and then enters the feed pipe (24).

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