Low-rank coal dewatering and upgrading device and use method thereof

Abstract

The invention discloses a low-rank coal dehydration and quality improvement device and a use method thereof, and belongs to the technical field of coal dehydration, the low-rank coal dehydration and quality improvement device comprises a saturated steam generation mechanism, a reaction kettle dehydration mechanism and a cyclone ash reduction mechanism, the reaction kettle dehydration mechanism comprises a reaction kettle body and a distribution plate, a high-pressure gas chamber is arranged at the lower part of the reaction kettle body, and the cyclone ash reduction mechanism is arranged at the lower part of the high-pressure gas chamber; the distribution plate is mounted at the upper part of the reaction kettle body and is positioned above the high-pressure gas chamber; the cyclone ash-reducing mechanism is communicated with the upper part of the reaction kettle body and is used for separating ash; the saturated steam generating mechanism is connected with a high-pressure gas chamber of the reaction kettle body and is used for conveying saturated steam to the high-pressure gas chamber; efficient dehydration, ash separation and calorific value increase of low-rank coal are achieved, energy consumption and environmental pollution are reduced, coal sample quality is improved, and the method is suitable for large-scale industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal dehydration, and in particular to a low-rank coal dehydration and quality-improvement device and a use method thereof. Background Art

[0002] my country is rich in coal resources. As of 2021, the country's cumulative coal output has reached 4.13 billion tons, of which low-rank coal accounts for more than 55% of the country's total output. Low-rank coal, especially lignite, has the advantages of large reserves and wide distribution, but its high moisture content, low calorific value, easy oxidation and weathering, and spontaneous combustion have seriously restricted its actual development and utilization value.

[0003] High moisture content is one of the most significant characteristics of lignite, which not only leads to low boiler combustion efficiency, releases a large amount of water vapor and particulate matter, aggravates environmental pollution, but also increases the operating costs of power plants and coal chemical projects. Therefore, developing an efficient dehydration and quality improvement technology to reduce the moisture content of lignite and increase the calorific value is the key to achieving efficient utilization of low-rank coal resources.

[0004] At present, traditional dehydration and drying methods such as hot air drying and fluidized bed drying have been widely used in industrial practice, but there are still many shortcomings. First, these methods rely on evaporating water, which consumes a lot of energy and leads to poor overall economic efficiency. Secondly, a large amount of tail gas emissions containing water vapor and particulate matter are generated during the drying process, which aggravates the problem of environmental pollution. In addition, the dried lignite is easy to absorb moisture and self-ignite, and there are serious dust problems, which bring safety hazards to storage and transportation. It can be seen that traditional dehydration methods are difficult to meet the needs of modern industry for efficient quality improvement of low-rank coal. Summary of the invention

[0005] In order to solve the problems of the prior art in the dehydration process of low-rank coal, such as high energy consumption, incomplete dehydration, poor ash separation effect, serious environmental pollution, and easy moisture absorption and spontaneous combustion of coal samples after drying, the present invention provides a low-rank coal dehydration and quality improvement device and a method for using the same.

[0006] On the one hand, the present invention is achieved through the following technical solutions: A low-rank coal dehydration and quality-improvement device with multi-layer fluidized drying and steam flash explosion, comprising a saturated steam generating mechanism, a reactor dehydration mechanism and a cyclone ash-reducing mechanism. The reactor dehydration mechanism comprises a reactor body and a distribution plate. A high-pressure gas chamber is provided at the lower part of the reactor body. The distribution plate is installed on the upper part of the reactor body and is located above the high-pressure gas chamber; The cyclone ash-removing mechanism is connected to the upper part of the reactor body for separating ash; The saturated steam generating mechanism is connected to the high-pressure gas chamber of the reactor body and is used for conveying saturated steam to the high-pressure gas chamber.

[0007] A further improvement of the present invention is that the distribution plates include a plurality of distribution plates, and the plurality of distribution plates are arranged in a left-right staggered manner in the reactor body.

[0008] A further improvement of the present invention is that the bottom of the dehydration mechanism of the reactor is an inverted cone outlet, and the inverted cone outlet is provided with a rotatable sealing mechanism.

[0009] A further improvement of the present invention is that the sealing mechanism includes a first electromagnetic valve and a shock-absorbing spring. When the first electromagnetic valve is powered on, it is adsorbed and blocked at the inverted cone outlet. When the power is off, the first electromagnetic valve is demagnetized and the shaft falls off from the inverted cone outlet.

[0010] A further improvement of the present invention is that the pore size of the distribution plate is 0.5-3 mm.

[0011] A further improvement of the present invention also includes a first steam heater and a second steam heater; one end of the first steam heater is connected to the saturated steam generating mechanism, and the other end of the first steam heater is connected to the saturated steam inlet of the reactor body; one end of the second steam heater is connected to the cyclone ash removal mechanism, and the other end of the second steam heater is connected to the saturated steam inlet of the reactor body.

[0012] A further improvement of the present invention further comprises a second electromagnetic valve, wherein the second electromagnetic valve is arranged between the cyclone ash removal mechanism and the reactor body.

[0013] A further improvement of the present invention is that it also includes a pressure gauge and a temperature gauge; the pressure gauge and the temperature gauge are arranged on the upper part of the reactor body.

[0014] Another aspect of the present invention is achieved through the following technical solutions: A method for using a low-rank coal dehydration and upgrading device comprises the following steps: Step 1: Saturated steam is prepared by a saturated steam generating mechanism and enters the high-pressure gas chamber of the reactor body through a delivery pipeline. The saturated steam is evenly directed upward after being divided by holes distributed in the high-pressure gas chamber; Step 2: Feed the raw coal into the reactor body through the feed port, and continue to input saturated steam. The raw coal forms a fluidized bed above the distribution plate under the dispersion effect of the saturated steam; Step 3: The small and medium-sized ash particles of the raw coal enter the cyclone driven by the rising steam, and the large coal particles pass through the distribution plate by their own weight and fall into the inverted cone-shaped material chamber at the bottom of the reactor; Step 4: The ash particles entering the cyclone move outward and downward under the action of centrifugal force and are discharged through the bottom flow port, while the saturated steam moves inward and upward and is discharged through the overflow port, and is recycled after being heated by the second steam heater; Step 5: After the material chamber at the bottom of the reactor is filled with coal particles, the feed inlet and the gas outlet are closed, and saturated steam is continued to be introduced; Step 6: When the pressure and temperature in the reactor reach the preset values, close the second electromagnetic valve of the saturated steam delivery pipeline to perform pressure maintenance operation; Step 7: After the pressure is maintained, the magnetic force of the sealing mechanism is released, and the sealing mechanism triggers steam ejection explosion under the action of steam pressure, and is ejected from the inverted cone outlet at high speed and is decelerated and stopped by the shock-absorbing spring; Step 8: The coal sample is cracked from the inside out, the moisture in the coal is quickly discharged and released into the atmosphere from the inverted cone outlet, completing instantaneous explosion to obtain a dehydrated coal sample.

[0015] A further improvement of the present invention is that the pressure in the dehydration reactor is 2MPa to 4MPa and the preset temperature is 200°C to 400°C.

[0016] It can be seen from the above technical solutions that the beneficial effects of the present invention are: The present invention provides a device and method for dehydrating and improving the quality of low-rank coal by means of multi-layer fluidized drying and coordinated steam flash explosion. Through the synergistic effect of high-temperature and high-pressure saturated steam and instantaneous steam flash explosion technology, efficient dehydration, deashing and quality improvement of low-rank coal are achieved, and remarkable technical effects are achieved.

[0017] First, the present invention uses a multi-layer distribution plate structure design to evenly distribute saturated steam to the fluidized bed, ensuring that coal particles are fully fluidized under the action of high-temperature and high-pressure saturated steam, increasing the contact area between steam and coal particles, and strengthening the heat and mass transfer effect, thereby accelerating the water replacement process on the surface and inside of the coal sample. The introduction of instantaneous steam flash explosion technology, through the rapid release of the sealing mechanism after high-temperature and high-pressure pressure maintenance, causes the high-pressure steam inside the coal particles to expand instantly, achieving the cracking of the coal sample from the inside out, and the rapid discharge of water. The moisture content can be reduced from the original 25%-35% to less than 10%, and the dehydration effect is significant.

[0018] Secondly, the present invention uses the cyclone ash reduction mechanism to effectively separate the fine ash carried by the steam in the coal sample, improve the purity of the coal sample, reduce the ash content, and further improve the quality of the coal. In addition, the steam recovery system set up in the device recovers and heats the excess steam through the overflow pipe and the second steam heater for recycling, which greatly reduces energy consumption, significantly improves the system energy efficiency, and reduces energy consumption by more than 15% compared with traditional drying technology.

[0019] Finally, through high temperature and high pressure, the oxygen-containing functional groups in the coal samples are effectively decomposed and reorganized, the calorific value of the coal is increased by 20%-30%, and the combustion performance of the coal is significantly enhanced. This device has a compact structure, small footprint, stable and reliable operation, is suitable for large-scale industrial applications, and helps promote the efficient, clean and economical use of low-rank coal resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of a specific implementation method of the present invention.

[0022] Figure 2 This is a schematic diagram of the movement of coal particles and ash particles in a dehydration reactor according to a specific embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the flow of saturated steam in a dehydration reactor according to a specific embodiment of the present invention.

[0024] In the attached drawings: 1. Steam generating mechanism; 2. First steam heater; 3. Second steam heater; 4. Cyclone ash reduction mechanism; 5. Second solenoid valve; 6. Pressure gauge; 7. Temperature gauge; 8. Distribution plate; 9. Overflow pipe; 10. High-pressure gas chamber; 11. Shock-absorbing spring; 12. First solenoid valve. DETAILED DESCRIPTION

[0025] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0026] Example 1 The present embodiment provides a low-rank coal dehydration and upgrading device using multi-layer fluidized drying and steam flash explosion, comprising a saturated steam generating mechanism 1 , a reactor dehydration mechanism and a cyclone ash reducing mechanism 4 .

[0027] The reactor dehydration mechanism includes a reactor body, a high-pressure gas chamber 10 is arranged at the lower part of the reactor body; a distribution plate 8 is installed at the upper part of the reactor body, above the high-pressure gas chamber 10, and the distribution plate 8 is provided with a plurality of distribution holes with an aperture of 0.5 to 3 mm; the distribution plates 8 are arranged in a left-right staggered manner to effectively separate the fluidized layer of the coal material, ensure uniform distribution of the material and the heat and mass transfer efficiency of the steam, and an overflow pipe 9 is installed at the tail end of the distribution plate 8, that is, near the outlet of the distribution plate 8, which can effectively guide the discharge of excess saturated steam to prevent excessive accumulation of steam in the area above the distribution plate 8 and affect the normal fluidization of the coal particles.

[0028] The bottom of the reactor body is an inverted cone outlet, and the inverted cone outlet is provided with a rotatable sealing mechanism; The sealing mechanism includes a first electromagnetic valve 12 and a damping spring 11. The first electromagnetic valve 12 absorbs and blocks the inverted cone outlet when energized, and releases the magnetic force under the action of high-pressure steam when powered off. The damping spring 11 is used to buffer the impact force when the sealing mechanism is released.

[0029] It also includes a first steam heater 2 and a second steam heater 3; one end of the first steam heater 2 is connected to the saturated steam generating mechanism 1, and the other end of the first steam heater 2 is connected to the saturated steam inlet of the reactor body; one end of the second steam heater 3 is connected to the cyclone ash removal mechanism 4, and the other end of the second steam heater 3 is connected to the saturated steam inlet of the reactor body. When in use, the saturated steam generating mechanism 1 prepares saturated steam, which is preheated by the first steam heater 2 and then sent into the high-pressure gas chamber 10 of the reactor body through the conveying pipeline; the second steam heater 3 is located between the cyclone ash removal mechanism 4 and the reactor body, and is used to recover and heat the exhausted steam to achieve steam recycling.

[0030] The cyclone ash-removing mechanism 4 is connected to the upper part of the reactor body and is used to separate small-size ash from the coal. The separated ash particles are discharged through the bottom flow port of the cyclone ash-removing mechanism 4, and the recovered steam moves inward and upward, and is heated by the second steam heater 3 before returning to the high-pressure gas chamber 10 for reuse.

[0031] The pressure gauge 6 and the temperature gauge 7 are arranged on the upper part of the reactor body to monitor the pressure and temperature in the reactor in real time to ensure the safety and stability of the dehydration and quality improvement process.

[0032] Embodiment 2, a method for using a low-rank coal dehydration and upgrading device, comprising the following steps: Step 1: Saturated steam preparation and delivery High-temperature and high-pressure saturated steam is prepared by the saturated steam generating mechanism 1 and enters the high-pressure gas chamber 10 of the reactor body through the delivery pipeline. A plurality of distribution holes are arranged in the high-pressure gas chamber 10, and the saturated steam is evenly transported upward after being divided by the distribution holes, creating conditions for subsequent fluidization and heat transfer.

[0033] Step 2: Fluidization of coal particles The raw coal is fed into the reactor body through the feed port, and saturated steam is continuously inputted at the same time. The saturated steam disperses through the distribution holes to form a stable fluidized bed layer above the distribution plate 8. The coal particles are fully contacted with the steam during the fluidization process, and the temperature rises rapidly and the water is initially dehydrated.

[0034] Step 3: Ash separation and particle settling The ash of small and medium particles in the raw coal enters the cyclone ash-reducing mechanism 4 driven by the rising steam, while the larger particles of coal pass through the distribution plate 8 under the action of their own weight and settle into the inverted cone-shaped material chamber at the bottom of the reactor body.

[0035] Step 4: Cyclone separation and steam recovery The small-size ash entering the cyclone ash-reducing mechanism 4 moves outward and downward under the action of centrifugal force and is discharged from the system through the bottom flow port of the cyclone. The recovered saturated steam moves inward and upward and is discharged through the overflow port of the cyclone. The steam is heated by the second steam heater 3 and then returns to the high-pressure gas chamber 10 for recycling.

[0036] Step 5: Material filling and system sealing After the inverted cone-shaped material chamber at the bottom of the reactor is filled with coal particles, the feed inlet and the gas outlet are closed, and saturated steam is continuously input into the high-pressure gas chamber 10 to ensure that the system is in a completely closed state.

[0037] Step 6: Pressure holding operation The pressure and temperature in the reactor are monitored in real time by the pressure gauge 6 and the thermometer 7. When the pressure stabilizes at 2 to 4 MPa and the temperature reaches 200 to 400 degrees Celsius, the second electromagnetic valve 5 of the saturated steam delivery pipeline is closed to maintain the system under high pressure and high temperature for a period of time (for example, 5 to 15 minutes) to ensure that the coal sample is fully heated.

[0038] Step 7: Steam Flash Trigger After the pressure maintenance is completed, the magnetic force of the sealing mechanism is released, and the first electromagnetic valve 12 is powered off and demagnetized. The sealing piston is pushed open at high speed by the high-pressure steam, and is decelerated by the damping spring 11 to ensure the stability of the equipment. The high-pressure steam in the coal sample is released instantly, triggering the steam flash explosion cracking of the coal particles from the inside out.

[0039] Step 8: Dehydrated coal sample discharge Under the action of steam flash explosion, the water in the coal sample is quickly replaced and discharged, and the coal particles are cracked. The cracked coal sample is discharged into the atmosphere from the inverted cone outlet, completing the instantaneous dehydration explosion operation and obtaining a dehydrated coal sample with improved quality.

[0040] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-rank coal dehydration and upgrading device, characterized in that: It comprises a saturated steam generating mechanism (1), a reaction kettle dehydrating mechanism and a cyclone ash reducing mechanism (4), The reactor dehydration mechanism comprises a reactor body and a distribution plate (8). A high-pressure gas chamber (10) is provided at the lower part of the reactor body. The distribution plate (8) is installed on the upper part of the reactor body and is located above the high-pressure gas chamber (10); The cyclone ash removal mechanism (4) is connected to the upper part of the reactor body for separating ash; The saturated steam generating mechanism (1) is connected to the high-pressure gas chamber (10) of the reactor body and is used to deliver saturated steam to the high-pressure gas chamber (10).

2. The low-rank coal dehydration and upgrading device according to claim 1 is characterized in that: The distribution plates (8) include a plurality of distribution plates (8), which are arranged in a left-right staggered manner in the reactor body.

3. The low-rank coal dehydration and upgrading device according to claim 2 is characterized in that: The bottom of the reactor dehydration mechanism is an inverted cone outlet, and the inverted cone outlet is provided with a rotatable sealing mechanism.

4. The low-rank coal dehydration and upgrading device according to claim 3 is characterized in that: The sealing mechanism comprises a first electromagnetic valve (12) and a damping spring (11); the first electromagnetic valve (12) is attracted and blocked at the inverted cone-shaped outlet when power is on; and the first electromagnetic valve (12) is demagnetized and falls off the inverted cone-shaped outlet when power is off.

5. The low-rank coal dehydration and upgrading device according to claim 2, characterized in that: The pore size of the distribution plate (8) is 0.5-3 mm.

6. The low-rank coal dehydration and upgrading device according to claim 1, characterized in that: The invention also comprises a first steam heater (2) and a second steam heater (3); one end of the first steam heater (2) is connected to the saturated steam generating mechanism (1), and the other end of the first steam heater (2) is connected to the saturated steam inlet of the reactor body; one end of the second steam heater (3) is connected to the cyclone ash removal mechanism (4), and the other end of the second steam heater (3) is connected to the saturated steam inlet of the reactor body.

7. The low-rank coal dehydration and upgrading device according to claim 6, characterized in that: It also comprises a second electromagnetic valve (5), wherein the second electromagnetic valve (5) is arranged between the cyclone ash removal mechanism (4) and the reactor body.

8. The low-rank coal dehydration and upgrading device according to claim 1, characterized in that: It also includes a pressure gauge (6) and a temperature gauge (7); the pressure gauge (6) and the temperature gauge (7) are arranged on the upper part of the reactor body.

9. A method for using a low-rank coal dehydration and upgrading device, characterized in that: The following steps are involved: Step 1: Saturated steam is prepared by a saturated steam generating mechanism and enters the high-pressure gas chamber of the reactor body through a delivery pipeline. The saturated steam is evenly directed upward after being divided by holes distributed in the high-pressure gas chamber; Step 2: Feed the raw coal into the reactor body through the feed port, and continue to input saturated steam. The raw coal forms a fluidized bed above the distribution plate under the dispersion effect of the saturated steam; Step 3: The small and medium-sized ash particles of the raw coal enter the cyclone driven by the rising steam, and the large coal particles pass through the distribution plate by their own weight and fall into the inverted cone-shaped material chamber at the bottom of the reactor; Step 4: The ash particles entering the cyclone move outward and downward under the action of centrifugal force and are discharged through the bottom flow port, and the saturated steam moves inward and upward and is discharged through the overflow port, and is recycled after being heated by the second steam heater; Step 5: After the material chamber at the bottom of the reactor is filled with coal particles, the feed inlet and the gas outlet are closed, and saturated steam is continued to be introduced; Step 6: When the pressure and temperature in the reactor reach the preset values, close the second electromagnetic valve of the saturated steam delivery pipeline to perform pressure maintenance operation; Step 7: After the pressure maintenance is completed, the magnetic force of the sealing mechanism is released, and the sealing mechanism triggers steam ejection explosion under the action of steam pressure, and it is ejected at high speed from the inverted cone outlet and decelerated and stopped by the damping spring; Step 8: The coal sample is cracked from the inside out, the moisture in the coal is quickly discharged and released into the atmosphere from the inverted cone outlet, completing instantaneous explosion to obtain a dehydrated coal sample.

10. The method for using the low-rank coal dehydration and upgrading device according to claim 9, characterized in that: The pressure in the dehydration reactor is 2 MPa~4 MPa and the temperature is preset to 200℃~400℃.

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