A system and method for dehydrating and upgrading low-rank coal by vibration mixed flow and steam flash explosion

Abstract

The present invention relates to a system and method for dehydrating and upgrading low-rank coal by vibration mixed flow coordinated with steam flash explosion, which belongs to the technical field of upgrading the quality of lignite or low-rank coal, and solves the problem in the prior art that the dehydration effect of existing lignite or low-rank coal is poor or the natural risk is high during the dehydration process. The present invention includes a vibration mixed flow unit and a steam flash explosion unit, the vibration mixed flow unit is used to pre-remove free water on the surface of the coal sample and realize a loose coal seam, and the steam flash explosion unit is used to remove capillary water in the coal treated by the vibration mixed flow unit. The present invention achieves high efficiency and low consumption in the dehydration process of lignite / low-rank coal through the coordinated use of vibration mixed flow dehydration and steam flash explosion dehydration, and the final coal sample temperature is low, the probability of spontaneous combustion is low, and the product safety factor is high.

Description

Technical Field

[0001] The present invention relates to the technical field of lignite or low-rank coal upgrading, and in particular to a system and method for dehydrating and upgrading low-rank coal by vibration mixed flow coordinated steam flash explosion. Background Art

[0002] It is imperative to efficiently improve the quality of lignite / low-rank coal.

[0003] The surface properties and pore structure of lignite / low-rank coal together lead to the generally high water content of this type of coal. The surface of lignite / low-rank coal is rich in various polar oxygen-containing functional groups, which makes the coal surface extremely hydrophilic; at the same time, lignite / low-rank coal particles contain a large number of pores. Under the combined effects of capillary action and surface hydrophilicity, lignite / low-rank coal contains a large amount of capillary water, resulting in excessive water content in the coal, which greatly hinders the promotion of efficient quality improvement and utilization of lignite / low-rank coal.

[0004] Existing coal dehydration equipment mainly uses mechanical extrusion dehydration and thermal dehydration. Mechanical extrusion dehydration is not effective in removing water stored in the micropores of lignite / low-rank coal, while thermal dehydration requires the input of heat energy from the system to achieve phase change of water stored in the micropores, resulting in excessive energy consumption for dehydration. At the same time, the temperature of thermal dehydration products is generally high, and there is a certain risk of spontaneous combustion.

[0005] It can be seen that designing a system and method for efficiently dehydrating and upgrading lignite / low-rank coal with low energy consumption, high efficiency, low product moisture content and extremely low risk of spontaneous combustion is of great significance for the efficient quality improvement and utilization of lignite / low-rank coal. Summary of the invention

[0006] In view of the above analysis, an embodiment of the present invention aims to provide a low-rank coal dehydration and quality improvement system and method with vibration mixed flow and coordinated steam flash explosion, so as to solve the problem of poor dehydration effect of existing lignite or low-rank coal or high natural risk in the dehydration process.

[0007] On the one hand, the present invention provides a low-rank coal dehydration and quality improvement system with vibration mixed flow and coordinated steam flash explosion, including a vibration mixed flow unit and a steam flash explosion unit. The vibration mixed flow unit is used to pre-remove free water on the surface of the coal sample and to achieve a loose coal seam, and the steam flash explosion unit is used to remove capillary water in the coal treated by the vibration mixed flow unit.

[0008] Furthermore, the vibration flow mixing unit includes a vibration flow mixing bin and a material storage bin, the vibration flow mixing bin is located at the upper part of the material storage bin, and the inner cavities of the vibration flow mixing bin and the material storage bin are connected.

[0009] Furthermore, the vibrating mixed flow unit includes a vibrating drying bed.

[0010] Furthermore, a material inlet pipe and an air outlet pipe are provided on the top of the vibrating mixed flow bin.

[0011] Furthermore, the steam flash explosion unit comprises a gas explosion shell and a gas explosion high-pressure chamber, and the gas explosion high-pressure chamber is arranged in the gas explosion shell.

[0012] Furthermore, the discharge port of the storage bin is connected to the gas explosion high-pressure bin through a feed guide pipe, and the opening and closing of the discharge port of the storage bin is controlled by a solenoid valve.

[0013] Furthermore, the steam explosion unit further includes a gas explosion chamber, which is arranged below the gas explosion shell, and the lower end of the gas explosion shell is located in the gas explosion chamber.

[0014] Furthermore, the steam flash explosion unit also includes a steam generator and a high-pressure gas storage tank, the steam generator is connected to the high-pressure gas storage tank, and the high-pressure gas storage tank is connected to the gas explosion high-pressure warehouse.

[0015] Furthermore, the vibration mixing unit also includes a flow diverter.

[0016] On the other hand, the present invention provides a method for dehydrating low-rank coal by vibration mixed flow coordinated steam flash explosion, using the above-mentioned low-rank coal dehydration system by vibration mixed flow coordinated steam flash explosion, the steps comprising:

[0017] Step S1: introducing dry air into the vibrating mixed flow chamber, starting the vibrating drying bed, and preparing saturated steam through a steam generator;

[0018] Step S2: conveying the coal sample to be dehydrated into the vibrating mixed flow bin for surface dehydration, and the hot air in the vibrating mixed flow bin is stored in a high-pressure gas storage tank after being diverted and heated;

[0019] Step S3: the coal sample after surface dehydration is transported to the gas explosion high-pressure chamber, and saturated steam is transported into the gas explosion high-pressure chamber to maintain the pressure;

[0020] Step S4: After the pressure maintenance is completed, the constraint of the gas explosion sealing valve is released, so that the coal sample in the gas explosion high-pressure chamber enters the gas explosion chamber, and the instantaneous gas explosion is completed to obtain the dehydrated product.

[0021] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0022] (1) The present invention realizes high efficiency and low consumption in the dehydration process of lignite / low-rank coal by the coordinated use of vibration mixed flow dehydration and steam flash explosion dehydration, and the final coal sample temperature is low, the probability of spontaneous combustion is low, and the product safety factor is high;

[0023] (2) The present invention uses vibration mixed flow dehydration to pre-remove free water on the surface of the coal sample and achieves the loosening of the incoming coal sample, which is more conducive to the invasion of superheated high-pressure water vapor into the coal pores in the subsequent steam flash explosion dehydration, thereby effectively improving the steam flash explosion dehydration efficiency;

[0024] (3) The present invention organically couples the vibration mixed flow dehydration and steam flash explosion dehydration processes by setting up a conical storage bin and designing the timing opening and closing of the electromagnetic valve, thereby achieving the continuity of the production process;

[0025] (4) The present invention finally removes capillary water in coal by steam flash dehydration, and the water is removed by high-speed expulsion in liquid form without phase change. The dehydration process has low energy consumption and high energy utilization rate;

[0026] (5) The present invention uses steam flash explosion to finally dehydrate the coal sample, and realizes high-speed expulsion and removal of water in the coal through extremely high-speed pressure relief of the high-pressure chamber. The steam explosion is completed almost instantly. The process is violent and efficient, and it is an adiabatic expansion process with low heat loss in the system. At the same time, the final product temperature is low (about 50°C), the probability of spontaneous combustion of the coal sample is low, and the product safety factor is high.

[0027] (6) In the present invention, after the air containing a large amount of water vapor after vibration mixed flow dehydration is diverted, part of the air is mixed with saturated water vapor as a high-temperature and high-pressure medium in the steam flash explosion process, thereby reducing the amount of steam used, reducing the working intensity of the steam generator and reducing the production cost;

[0028] (7) The high-temperature and high-pressure medium in the steam flash explosion machine of the present invention is the water vapor generated by the steam generator and the air containing a large amount of water vapor discharged from the vibrating mixed flow dryer. Compared with using water vapor alone, the reforming process reduces the working intensity of the steam generator and reduces the production cost.

[0029] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0031] Figure 1 It is a structural schematic diagram of a low-rank coal dehydration and upgrading system using vibration mixed flow coordinated steam flash explosion in a specific embodiment.

[0032] Reference numerals:

[0033] 100-vibration mixed flow unit; 101-dehydration reactor; 102-vibration mixed flow bin; 103-storage bin; 104-vibration drying bed; 105-drying bed shock absorber; 106-crossbeam; 107-material guide plate; 108-feeding pipe; 109-air outlet pipe; 110-solenoid valve; 111-first air inlet pipe; 112-first shock absorber; 113-flow divider;

[0034] 200-steam flash explosion unit; 201-gas explosion shell; 202-gas explosion high-pressure chamber; 203-gas explosion cover; 204-gas explosion sealing valve; 205-sealing cover plate; 206-shock-absorbing spring; 207-feeding pipe; 208-gas explosion chamber; 209-third discharge port; 210-second shock absorber; 211-second air inlet pipe; 212-air heater; 213-steam generator; 214-steam heater; 215-high-pressure gas storage tank. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0036] Example 1

[0037] A specific embodiment of the present invention, as Figure 1 As shown, a low-rank coal dehydration system of vibration mixed flow coordinated with steam flash explosion is disclosed, including a vibration mixed flow unit 100 and a steam flash explosion unit 200. The vibration mixed flow unit 100 is used to pre-remove free water on the surface of the coal sample and to achieve a loose coal seam, and the steam flash explosion unit 200 is used to remove capillary water in the coal treated by the vibration mixed flow unit 100.

[0038] Compared with the prior art, the low-rank coal dehydration and quality improvement system of vibration mixed flow coordinated steam flash explosion provided in this embodiment uses vibration mixed flow dehydration to pre-remove free water on the surface of the coal sample and realizes the loosening of the input coal sample, which is more conducive to the invasion of superheated high-pressure water vapor into the coal pores in the subsequent steam flash explosion dehydration, and effectively improves the steam flash explosion dehydration efficiency; the coal sample is finally dehydrated by steam flash explosion, and the high-speed drainage and removal of water in the coal is achieved by extremely high-speed pressure relief of the high-pressure bin, and the steam explosion is completed almost instantly. The process is violent and efficient, and is an adiabatic expansion process with small heat loss in the system; at the same time, the final product temperature is low (about 50°C), the probability of spontaneous combustion of the coal sample is low, and the product safety factor is high.

[0039] The vibration mixed flow unit 100 includes a dehydration reactor 101, and the dehydration reactor 101 includes a vibration mixed flow bin 102 and a storage bin 103. The vibration mixed flow bin 102 is located at the upper part of the storage bin 103, and the inner cavities of the vibration mixed flow bin 102 and the storage bin 103 are connected, and the coal sample falling from the vibration mixed flow bin 102 is temporarily stored in the storage bin 103. Preferably, the vibration mixed flow bin 102 is a columnar structure, exemplarily a cylindrical or rectangular parallelepiped tube, and the storage bin 103 is an inverted cone structure, and the vibration mixed flow bin 102 and the storage bin 103 are concentrically arranged.

[0040] In order to achieve dehydration of the coal sample during the vibration process, the vibration mixed flow unit 100 further includes a vibration drying bed 104. A plurality of vibration drying beds 104 are provided, preferably 3 to 5. In this embodiment, three vibration drying beds 104 are provided. The plurality of vibration drying beds 104 are arranged in a zigzag shape from top to bottom in the vibration mixed flow bin 102.

[0041] Specifically, a single vibration drying bed 104 is arranged obliquely, and the angle between the plane of the vibration drying bed 104 contacting the coal sample and the horizontal plane is 10° to 30°. Preferably, the inclination angle of the vibration drying bed 104 is 15°. In this embodiment, the vibration drying bed 104 is arranged obliquely in the vibration mixed flow chamber 102, and the tails of the two adjacent vibration drying beds 104 are connected to each other in a zigzag shape.

[0042] Furthermore, the mesh diameter of the vibration drying bed 104 is 0.5-3 mm, and the mesh diameter of the vibration drying bed 104 gradually decreases from the uppermost vibration drying bed 104 to the lowermost vibration drying bed 104. That is, the mesh diameter of the uppermost vibration drying bed 104 is the largest (≤3 mm), and the mesh diameter of the lowermost vibration drying bed 104 is the smallest (≥0.5 mm).

[0043] In this embodiment, the sieve hole diameter of the vibrating drying bed 104 decreases layer by layer from top to bottom, so that the fine particles in the coal sample leak out in advance. The fine particles contact the dry air for dehydration during the falling process. Compared with the stacked state, the scattered fine particles (formed by falling) are more fully in contact with the dry air and the dehydration effect is better. At the same time, after the fine particles in the coal sample fall, what remains are large particles with relatively uniform particle sizes. At this time, the fine particles and the large particles are no longer mixed with each other, which avoids the situation where the fine particles fill the gaps in the large particles and the dry air is not easy to enter the gaps to contact the materials for dehydration.

[0044] Since the vibrating drying bed 104 vibrates for a long time in the vibrating mixed flow chamber 102 , it will bring shock and vibration to the vibrating mixed flow chamber 102 . In order to reduce the damage to the operation of the equipment, the vibrating mixed flow unit 100 also includes a drying bed shock absorber 105 .

[0045] Each vibrating drying bed 104 is equipped with a set of drying bed shock absorbers 105, a crossbeam 106 is provided in the vibrating mixed flow chamber 102, one end of the drying bed shock absorber 105 is connected to the crossbeam 106, and the other end is connected to the vibrating drying bed 104. It can be understood that the vibrating drying bed 104 of this embodiment is suspended in the vibrating mixed flow chamber 102 through the drying bed shock absorbers 105.

[0046] In this embodiment, the vibrating drying bed 104 is provided with a drying bed shock absorber 105, and the drying bed shock absorber 105 is used to mitigate the impact and vibration of the vibrating drying bed 104 on the vibrating mixed flow chamber 102, so as to extend the service life of the equipment.

[0047] Since the vibrating drying beds 104 are arranged in a zigzag shape in the vibrating mixed flow bin 102, in order to enable the coal sample to flow smoothly between the vibrating drying beds 104 connected in a zigzag shape, a material guide plate 107 is further provided between the tail ends of two adjacent vibrating drying beds 104, that is, the material guide plate 107 connects the discharge end of the previous vibrating drying bed 104 and the feed end of the next vibrating drying bed 104, so that a smooth coal sample flow path is formed inside the vibrating mixed flow bin 102.

[0048] In this embodiment, after the coal sample is transported into the vibrating mixed flow bin 102, the coal sample moves on the coal flow channel formed by the vibrating drying bed 104 and the guide plate 107. Due to the vibration of the vibrating drying bed 104, the small-sized coal (dilute phase material) in the coal sample will first fall directly downward from the screen. During the falling process, the small-sized coal will fully contact with the dry air for dehydration. Under the vibration of the vibrating drying bed 104, the coal sample forms a loose coal layer on the screen so as to contact with the dry air for dehydration.

[0049] It can be understood that a feed pipe 108 for inputting coal samples is provided at the top of the vibrating mixed flow bin 102, and the bottom of the feed pipe 108 is just located at the feed end of the uppermost vibrating drying bed 104, and the coal sample transported from the feed pipe 108 just falls on the vibrating drying bed 104. An air outlet pipe 109 is also provided at the top center of the vibrating mixed flow bin 102.

[0050] A first discharge port is provided at the bottom of the storage bin 103, and the opening and closing of the first discharge port is controlled by a solenoid valve 110, and the solenoid valve 110 is located outside the storage bin 103. A first air inlet pipe 111 for conveying dry air is provided on the side wall of the storage bin 103, and the first air inlet pipe 111 is not higher than the bottom of the vibration drying bed 104 at the lowest end.

[0051] The steam explosion unit 200 includes a gas explosion shell 201 and a gas explosion high-pressure chamber 202. The gas explosion high-pressure chamber 202 is arranged in the gas explosion shell 201. In order to reduce the heat, pressure and steam loss of the system, a gap is provided between the gas explosion high-pressure chamber 202 and the gas explosion shell 201, and the gap is filled with thermal insulation material. In this embodiment, due to the instantaneous pressure difference in the flash explosion process, the single-layer shell structure has poor impact resistance, so a gas explosion shell 201 is added on the outside of the gas explosion high-pressure chamber 202.

[0052] The gas explosion shell 201 and the gas explosion high pressure chamber 202 are concentrically arranged, and the tops and bottoms of the two are flush. A gas explosion cover 203 is arranged on the top of the gas explosion shell 201. Since the tops of the gas explosion shell 201 and the gas explosion high pressure chamber 202 are flush, the gas explosion cover 203 can simultaneously seal the upper end openings of the gas explosion shell 201 and the gas explosion high pressure chamber 202. The dehydration reactor 101 is arranged on the gas explosion cover 203 through a bracket. In order to reduce the damage to the lower equipment caused by the vibration of the vibrating mixed flow chamber 102, a first shock absorber 112 is arranged on the bracket.

[0053] A second discharge port is provided at the bottom of the gas explosion high-pressure chamber 202, and a gas explosion sealing valve 204 is provided at the second discharge port, and the gas explosion sealing valve 204 is used to control the opening and closing of the second discharge port. The gas explosion sealing valve 204 has an electromagnetic structure, and when powered on, it is adsorbed on the gas explosion housing 201 and the lower end of the gas explosion high-pressure chamber 202 to seal the second discharge port, thereby achieving the sealing of the gas explosion high-pressure chamber 202; at the same time, the gas explosion sealing valve 204 has a spring structure, and when powered off, the gas explosion sealing valve 204 is quickly opened to achieve instantaneous pressure relief of the gas explosion high-pressure chamber 202.

[0054] Specifically, the gas explosion sealing valve 204 includes a sealing cover plate 205 and a shock absorbing spring 206 . One side of the sealing cover plate 205 is hinged to the bottom of the gas explosion housing 201 , and the other side is connected to the bottom of the gas explosion housing 201 through the shock absorbing spring 206 .

[0055] In order to realize automatic control of the opening and closing of the sealing cover plate 205, an electromagnet is provided at the connection side of the sealing cover plate 205 and the damping spring 206. When the electromagnet is energized, a magnetic force is generated to seal the sealing cover plate 205 with the second discharge port. When the sealing cover plate 205 needs to be opened, the electromagnet loses power, and the sealing cover plate 205 is opened under the elastic force of the damping spring 206 and the pressure in the gas explosion high-pressure chamber 202. In order to obtain a better sealing effect, a sealing gasket (not shown in the figure) is provided at the connection side of the sealing cover plate 205 and the second discharge port. Preferably, the sealing gasket is a rubber gasket, and the elasticity of the rubber gasket is used to obtain a better sealing effect.

[0056] In order to connect the storage bin 103 and the gas explosion high-pressure bin 202 , a feed pipe 207 is provided between the first discharge port and the gas explosion high-pressure bin 202 , and the lower end of the feed pipe 207 passes through the gas explosion cover 203 . Preferably, the feed pipe 207 passes through the center of the gas explosion cover 203 .

[0057] The gas explosion housing 201 is connected to the gas explosion bin 208 below, and the lower end of the gas explosion housing 201 (in an inverted cone structure) is located in the gas explosion bin 208. It can be understood that the gas explosion sealing valve 204 is located in the gas explosion bin 208, and the coal sample flowing out of the second discharge port directly falls into the gas explosion bin 208. The bottom of the gas explosion bin 208 is provided with a third discharge port 209. In order to facilitate the coal sample to gather at the third discharge port 209, the lower part of the gas explosion bin 208 is an inverted cone structure. In this embodiment, the gas explosion housing 201, the gas explosion high-pressure bin 202 and the gas explosion bin 208 are concentrically arranged.

[0058] A second shock absorber 210 is provided on the outer side of the bottom of the gas explosion chamber 208. The second shock absorber 210 performs shock absorption treatment on the overall vibration during the operation of the equipment, including but not limited to the vibration generated by the vibrating mixed flow chamber 102 and its internal equipment, and the vibration generated by the instantaneous pressure reduction process of the steam flash explosion. If the equipment is directly rigidly connected to the ground, the vibration will be directly transmitted to the mounting platform and will also react to the equipment itself, which is not conducive to the long-term operation of the equipment. By setting up the second shock absorber 210, the adverse effects of the reaction can be greatly alleviated, and the long-term stable operation of the equipment can be maintained.

[0059] In order to introduce saturated steam into the gas explosion high-pressure chamber 202, a second air inlet pipe 211 is provided below the gas explosion cover 203, and one end of the second air inlet pipe 211 passes through the gas explosion shell 201 and the outer wall of the gas explosion high-pressure chamber 202 in turn to enter the gas explosion high-pressure chamber 202.

[0060] The vibration mixed flow unit 100 further includes a flow divider 113, which has an air inlet and two air outlets, and the air inlet of the flow divider 113 is connected to the air outlet pipe 109. The steam flash explosion unit 200 further includes an air heater 212, a steam generator 213, a steam heater 214 and a high-pressure gas storage tank 215. One air outlet of the flow divider 113 is directly connected to the atmosphere, and the other air outlet is connected to the air inlet of the air heater 212, that is, part of the gas discharged from the flow divider 113 is directly discharged into the atmosphere, and the other part is discharged into the air heater 212. The steam generator 213 is connected to the air inlet of the steam heater 214, and the air outlet of the steam heater 214 and the air outlet of the air heater 212 are both connected to the high-pressure gas storage tank 215, and the high-pressure gas storage tank 215 is connected to the second air inlet pipe 211 to transport saturated steam to the gas explosion high-pressure chamber 202.

[0061] It should be noted that although the gas discharged from the vibrating mixed flow chamber 102 is humid and hot, its moisture content is obviously insufficient compared with the saturated steam generated by the steam generator 213. If too much is mixed in, it may not be able to meet the steam flash explosion requirements. Therefore, the amount of gas diverted into the high-pressure gas storage tank 215 through the diverter 113 is approximately 1 / 2 of the amount of gas passed from the steam generator 213 into the high-pressure gas storage tank 215, and the remaining gas is directly discharged into the atmosphere.

[0062] Example 2

[0063] A specific embodiment of the present invention, as Figure 1 As shown, a low-rank coal dehydration system with vibration mixed flow and steam flash explosion is disclosed. The difference from Example 1 is that a guide plate (not shown in the figure) is provided in the vibration mixed flow bin 102. The guide plate is located below the lowermost vibration drying bed 104. The guide plate is similar to a carambola-shaped structure and can rotate along its axis in the vibration mixed flow bin 102 to redirect the dry air entering the vibration mixed flow bin 102.

[0064] In order to further dehydrate the coal sample, a blower (not shown in the figure) is also provided in the vibrating mixed flow chamber 102. The blower is located on both sides of the guide plate, at the same horizontal height as the guide plate, and the air outlet faces the guide plate. The direction of the air outlet of the blower is adjustable.

[0065] It should be noted that the position of the dry air inlet is not higher than the lowest vibration drying bed 104 and not lower than the height of the blower. The remaining structures and beneficial effects are the same as those of embodiment 1 and will not be described in detail here.

[0066] Example 3

[0067] Another specific embodiment of the present invention, as Figure 1 As shown, a method for upgrading low-rank coal by vibration mixed flow and steam flash explosion is disclosed, and the low-rank coal upgrading system by vibration mixed flow and steam flash explosion of embodiment 1 or embodiment 2 is adopted, and the steps include:

[0068] Step S1: dry air is introduced into the vibrating mixed flow chamber 102 , the vibrating drying bed 104 is turned on, and saturated steam is prepared by the steam generator 213 .

[0069] Specifically, dry air is introduced into the vibrating mixed flow bin 102 through the first air inlet pipe 111, and the dry air forms an ascending hot air flow in the vibrating mixed flow bin 102; at the same time, the vibrating drying bed 104 is turned on, the solenoid valve 110 is closed, and the storage bin 103 and the gas explosion high-pressure bin 202 are not connected; the gas explosion sealing valve 204 is closed, and the gas explosion bin 208 is sealed.

[0070] The steam generator 213 is turned on to generate saturated steam. After the saturated steam is heated to about 280° C. by the steam heater 214 , the high-temperature saturated steam is passed into the high-pressure gas storage tank 215 for storage.

[0071] Step S2: The coal sample to be processed is transported into the vibrating mixed flow bin 102 for surface dehydration. The hot air in the vibrating mixed flow bin 102 is stored in the high-pressure gas storage tank 215 after being diverted and heated.

[0072] Specifically, the -6 mm coal sample to be dehydrated is fed into the vibrating drying bed 104 in the vibrating mixed flow bin 102 through the feed pipe 108. Under the action of the vibrating drying bed 104, the coal sample is flattened and screened. During the movement of the screen surface of the vibrating drying bed 104, the coal particles come into contact with the rising hot air flow, so that the surface moisture of the coal sample evaporates. When the coal flow moves to the discharge port of the vibrating drying bed 104, the coal flow enters the screen surface of the next vibrating drying bed 104 under the action of the guide plate 107, and comes into contact with the rising hot air flow again. The coal sample that was not fully dried in the previous vibrating drying bed 104 is dehydrated again on the surface. Finally, all the coal samples enter the storage bin 103 after being dried.

[0073] The dry rising heat flow carries a large amount of water vapor in the coal sample upward and enters the diverter 113 through the outlet pipe 109. The hot air containing a large amount of water vapor is diverted in the diverter 113, part of which is directly discharged into the atmosphere, and part of which is heated to about 280°C by the air heater 212. The high-temperature air and the high-temperature saturated water vapor enter the high-pressure gas storage tank 215 together.

[0074] It should be noted that in this step, when a guide plate and a blower are provided in the vibrating mixed flow chamber 102, the blower can be turned on to accelerate the flow of dry air.

[0075] Step S3: the coal sample after surface dehydration is input into the gas explosion high-pressure chamber 202, and saturated steam is transported into the gas explosion high-pressure chamber 202 to maintain the pressure.

[0076] Specifically, the solenoid valve 110 is opened, and the coal sample after surface dehydration enters the gas explosion high-pressure chamber 202 from the storage bin 103 through the feed pipe 207. After the predetermined time (3 minutes), the solenoid valve 110 is closed, and all components in the vibration mixed flow chamber 102 continue to operate to dehydrate the coal sample. The initially dehydrated coal sample is stored in the storage bin 103.

[0077] The high-pressure gas storage tank 215 begins to input high-temperature and high-pressure water vapor to the gas explosion high-pressure chamber 202 through the second air inlet pipe 211. After the pressure in the gas explosion high-pressure chamber 202 reaches 3.0 Mpa, the input of high-temperature and high-pressure water vapor is stopped, and the gas explosion high-pressure chamber 202 begins to maintain pressure. At this time, the superheated water vapor begins to invade the internal pore structure of the coal sample, and begins to replace the capillary water in the coal pores and discharge the water in the pores; at the same time, the huge energy of the water vapor also destroys and reorganizes the crystalline areas and hydrogen bonds in the molecular structure of the coal surface, thereby modifying the surface properties of the coal.

[0078] Step S4: After the pressure maintenance is completed, the constraint of the gas explosion sealing valve 204 is released, so that the coal sample in the gas explosion high-pressure chamber 202 enters the gas explosion chamber 208, and the instantaneous gas explosion is completed to obtain the dehydrated product.

[0079] Specifically, after maintaining the pressure for 5 minutes, the electromagnetic force constraint of the gas explosion sealing valve 204 is released, and under the combined action of the internal and external pressure difference and the spring structure, the gas explosion sealing valve 204 pops open at high speed from the second discharge port of the gas explosion high-pressure bin 202, and the coal sample and water vapor in the gas explosion high-pressure bin 202 rapidly drop under the action of the pressure difference and enter the gas explosion bin 208; there is a large amount of high-pressure water vapor in the internal pores of the coal sample, and the external instantaneous pressure drop causes the coal to explode from the inside out, completing the instantaneous explosion, and finally being discharged from the discharge port connected to the gas explosion bin 208 to become the final product.

[0080] Step S5: Repeat steps S3 to S4 to continue dehydrating the coal sample to be dehydrated.

[0081] Specifically, after the gas explosion dehydrated coal sample is discharged, the solenoid valve 110 is opened again, and the coal sample in the storage bin 103 enters the gas explosion high-pressure bin 202 again through the feed pipe 207. After the set time of 3 minutes is reached, the solenoid valve 110 is closed again, and the gas explosion dehydration operation is started again.

[0082] In this embodiment, in order to achieve the continuity of production, the opening and closing time of the electromagnetic valve 110 are set to 3 minutes and 10 minutes respectively. The contradiction of the continuous production of the coal sample dehydration process is that the vibration mixed flow pre-dehydration process is a continuous production, while the gas explosion dehydration process is discontinuous (similar to a pressure filter). In order to achieve the continuity of production, a storage bin 103 is set at the bottom of the vibration mixed flow bin 102, and the opening and closing rules of the electromagnetic valve 110 are set. The solenoid valve 110 is closed, and high-temperature and high-pressure gas begins to flow into the gas explosion high-pressure chamber 202. The set pressure is reached after about 3 minutes. After 5 minutes of pressure stabilization, the gas explosion sealing valve 204 is opened, the gas explosion occurs and the dehydrated coal sample is discharged. After about 2 minutes, all the coal samples are discharged and the gas explosion sealing valve 204 is closed. The solenoid valve 110 is opened, and the materials stored in the storage bin 103 that were vibrated and dehydrated for the previous 10 minutes enter the gas explosion high-pressure chamber 202. After 3 minutes, the previous stored materials and the newly produced coal samples that were vibrated and dehydrated during the opening process all enter the gas explosion high-pressure chamber 202. The solenoid valve 110 is closed again, and high-temperature and high-pressure gas is introduced into the gas explosion high-pressure chamber 202. The storage bin 103 begins to store materials. Overall, continuous production of the dehydration process is achieved.

[0083] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for dehydrating low-rank coal by vibration mixed flow and steam flash explosion, characterized in that: A low-rank coal dehydration system using vibration mixed flow coordinated with steam flash explosion, the low-rank coal dehydration system comprising a vibration mixed flow unit (100) and a steam flash explosion unit (200), the vibration mixed flow unit (100) being used to pre-remove free water on the surface of the coal sample and to achieve a loose coal seam, and the steam flash explosion unit (200) being used to remove capillary water in the coal treated by the vibration mixed flow unit (100); The vibration mixed flow unit (100) comprises a dehydration reaction kettle (101) and a flow divider (113); the dehydration reaction kettle (101) comprises a vibration mixed flow bin (102) and a material storage bin (103); the vibration mixed flow bin (102) is located at the upper part of the material storage bin (103); and the inner cavities of the vibration mixed flow bin (102) and the material storage bin (103) are in communication; the steam flash explosion unit (200) comprises a gas explosion housing (201) and a gas explosion high-pressure bin (202); the gas explosion high-pressure bin (202) is arranged in the gas explosion housing (201); the discharge port of the storage bin (103) is connected to the gas explosion high-pressure bin (202) through a feed guide pipe (207), and the opening and closing of the discharge port of the storage bin (103) is controlled by a solenoid valve (110); the steam flash explosion unit (200) further comprises a gas explosion bin (208), the gas explosion bin (208) is arranged below the gas explosion housing (201), and the lower end of the gas explosion housing (201) is located in the gas explosion bin (208); A gap is provided between the gas explosion high-pressure chamber (202) and the gas explosion housing (201), and the gap is filled with a heat-insulating material; The top of the gas explosion housing (201) is provided with a gas explosion cover (203), and the gas explosion cover (203) can simultaneously seal the gas explosion housing (201) and the upper end opening of the gas explosion high-pressure chamber (202); the dehydration reactor (101) is arranged on the gas explosion cover (203) through a bracket, and the bracket is provided with a first shock absorber (112); the bottom of the gas explosion high-pressure chamber (202) is provided with a second discharge port, and the second discharge port is provided with a gas explosion sealing valve (204), and the gas explosion sealing valve (204) is used to control the second discharge port. The opening and closing of the material port realizes instantaneous pressure relief of the gas explosion high-pressure chamber (202); the gas explosion sealing valve (204) comprises a sealing cover plate (205) and a shock absorbing spring (206); one side of the sealing cover plate (205) is hinged to the bottom of the gas explosion housing (201); the other side is connected to the bottom of the gas explosion housing (201) via the shock absorbing spring (206); an electromagnet is provided on the connection side between the sealing cover plate (205) and the shock absorbing spring (206); and a second shock absorber (210) is provided on the outer side of the bottom of the gas explosion chamber (208); A blower and a guide plate with a carambola-shaped structure are provided in the vibrating mixed flow chamber (102), the blower is located on both sides of the guide plate and at the same level as the guide plate, and the air outlet of the blower faces the guide plate; The steam flash explosion unit (200) further comprises an air heater (212), a steam generator (213), a steam heater (214) and a high-pressure gas storage tank (215); the steam generator (213) is in communication with an air inlet of the steam heater (214); the air outlet of the steam heater (214) and the air outlet of the air heater (212) are both in communication with the high-pressure gas storage tank (215); the high-pressure gas storage tank (215) is in communication with the gas explosion high-pressure chamber (202); the air inlet of the flow divider (113) is in communication with an air outlet pipe (109) at the top of the vibration mixed flow chamber (102); one air outlet of the flow divider (113) is directly in communication with the atmosphere, and the other air outlet is in communication with an air inlet of the air heater (212); The low-rank coal dehydration method comprises the following steps: Step S1: introducing dry air into the vibrating mixed flow chamber (102), starting the vibrating drying bed (104), and preparing saturated steam through the steam generator (213); Step S2: conveying the coal sample to be dehydrated into the vibrating mixed flow bin (102) for surface dehydration, and the hot air in the vibrating mixed flow bin (102) is divided and heated and then stored in a high-pressure gas storage tank (215); Step S3: the coal sample after surface dehydration is transported to the gas explosion high-pressure chamber (202), and saturated steam is transported into the gas explosion high-pressure chamber (202) to maintain the pressure; Step S4: After the pressure maintenance is completed, the constraint of the gas explosion sealing valve (204) is released, so that the coal sample in the gas explosion high-pressure chamber (202) enters the gas explosion chamber (208), and the instantaneous gas explosion is completed to obtain the dehydrated product.

2. The method for dehydrating low-rank coal by vibration mixed flow coordinated steam flash explosion according to claim 1, characterized in that: The vibrating mixed flow unit (100) comprises a vibrating drying bed (104).

3. The method for dehydrating low-rank coal by vibration mixed flow coordinated steam flash explosion according to claim 2, characterized in that: A material inlet pipe (108) and an air outlet pipe (109) are provided on the top of the vibrating mixed flow bin (102).

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