A low rank coal pressurized pyrolysis device and method
By using a pressurized pyrolysis device and method for low-rank coal, and utilizing a pressurized structure and hydrogen atmosphere, the problems of low coal tar yield and low calorific value of raw coal gas in the pyrolysis of low-rank coal pulverized coal were solved, achieving the effects of increasing coal tar yield and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XINXING HUIER GREEN TECHNOLOGY CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-09
AI Technical Summary
In existing low-rank coal pulverized coal pyrolysis processes, the coal tar yield is low, the calorific value of raw coal gas is low, the scale of the equipment is limited, and the energy consumption is high.
The low-rank coal pressurized pyrolysis unit includes a top silo, a pyrolysis reactor, a fractionation tower, a gas-liquid separator, and a hydrogen production unit. Through pressurization, hydrogen atmosphere, and stratified gas intake, it improves coal tar yield and coal gas calorific value while reducing energy consumption.
It significantly improved coal tar yield and coal gas calorific value, reduced fine powder escape, lowered energy consumption, and improved throughput and gas distribution uniformity.
Smart Images
Figure CN122168311A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal chemical technology, and in particular to a pressurized pyrolysis apparatus and method for low-rank coal. Background Technology
[0002] Low-rank coal, including lignite, sub-bituminous coal, long-flame coal, non-caking coal, and weakly caking coal, is abundant. Low-rank coal is characterized by high moisture content, high impurity content, low calorific value, high oxygen content, and low hydrophobicity. Based on these characteristics, low-rank coal is converted into gas (raw coal gas), liquid (coal tar), and solid (semi-coke) products through medium- and low-temperature pyrolysis. Raw coal gas can be further processed for utilization, such as hydrogen extraction and methane extraction. Coal tar can be further processed for utilization, such as hydrogenation to produce gasoline and diesel. Semi-coke can be used for applications such as blast furnace injection, gasification to produce syngas, and clean combustion. This staged processing method improves resource utilization and economic efficiency.
[0003] In existing low-rank coal pulverized coal pyrolysis processes, the yield of coal tar is low, and the calorific value of raw coal gas is low. In order to improve the calorific value of raw coal gas, external heating methods or oxygen-enriched or pure oxygen combustion are used to reduce the nitrogen content in the raw coal gas. These methods have achieved certain results, but the scale of the equipment is limited and the energy consumption is relatively high. Summary of the Invention
[0004] The purpose of this invention is to provide a low-rank coal pressurized pyrolysis device and method to solve the problems existing in the prior art, thereby increasing the yield of coal tar, increasing the calorific value of coal gas, and reducing energy consumption.
[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a low-rank coal pressurized pyrolysis device, comprising: a top hopper structure, a feed hopper structure, a pyrolysis reactor, a discharge hopper structure, a fractionation tower, a gas-liquid separator, and a hydrogen production device. The top hopper structure, the feed hopper structure, the pyrolysis reactor, and the discharge hopper structure are arranged from top to bottom and connected sequentially. The upper end of the pyrolysis reactor is provided with a feed inlet, and the lower end of the pyrolysis reactor is provided with a discharge outlet. The pyrolysis reactor is connected to a pressurization structure, which is used to regulate the pressure inside the pyrolysis reactor. The pyrolysis reactor is provided with a gas collecting structure, a gas distribution structure, and a cooling structure arranged from top to bottom. The gas distribution structure is used to introduce a heat medium, and the gas collecting structure is used to collect gas. The gas collecting structure is connected to the fractionation tower, and the fractionation tower is connected to the gas-liquid separator. The gas-liquid separator is connected to both the gas distribution structure and the hydrogen production device, and the hydrogen production device is connected to the gas distribution structure. The gas-liquid separator is used to obtain coal gas, and the hydrogen production device is used to obtain hydrogen.
[0006] In some specific embodiments, the top hopper structure includes a top hopper body, an agitator, and a heating structure. The agitator is located in the top hopper body, and the heating structure is used to heat the material in the top hopper body.
[0007] In some specific embodiments, a first control valve is provided between the feed hopper structure and the top hopper structure, and a second control valve is provided between the feed hopper structure and the pyrolysis reactor; A third control valve is provided between the discharge hopper structure and the pyrolysis reactor, and a fourth control valve is provided at the outlet of the discharge hopper structure.
[0008] In some specific embodiments, the pyrolysis reactor is provided with a temperature regulating structure for regulating the temperature of the pyrolysis reactor; or, the inner wall of the pyrolysis reactor is provided with a refractory layer or a high-temperature resistant layer.
[0009] In some specific embodiments, the gas collection structure includes at least two gas collection components arranged from top to bottom.
[0010] In some specific embodiments, the gas distribution structure includes at least two gas distribution components, namely a steam distribution component and a hydrogen distribution component. The steam distribution component is used to introduce steam, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component is located above the hydrogen distribution component.
[0011] In some specific embodiments, the gas distribution structure includes at least three gas distribution components, namely a steam distribution component, a coal gas distribution component, and a hydrogen distribution component. The steam distribution component is used to introduce steam, the coal gas distribution component is used to introduce coal gas, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component, the coal gas distribution component, and the hydrogen distribution component are arranged from top to bottom.
[0012] In some specific designs, a condenser is provided between the fractionation tower and the gas-liquid separator; a compressor is provided downstream of the gas-liquid separator, and the coal gas obtained from the gas-liquid separator is pressurized by the compressor and then introduced into the gas distribution structure and the hydrogen production device.
[0013] The present invention also provides a method for pressurizing low-rank coal using the aforementioned low-rank coal pressurized pyrolysis device, comprising: The material enters the top hopper structure and is dried there. The dried material enters the feed hopper and then enters the pyrolysis reactor; A heat medium is introduced into the pyrolysis reactor through a gas distribution structure. After the heat medium interacts with the material, the generated gas is collected through a gas collection structure and enters a fractionation tower. In the fractionation tower, heavy coal tar is obtained at the bottom of the tower. The gas obtained from fractionation enters a gas-liquid separator, which produces wastewater, light coal tar, and coal gas. A portion of the coal gas is used as a product, while the remaining coal gas is pressurized and enters a hydrogen production unit, or it can be returned to the gas distribution structure and enter the hydrogen production unit simultaneously. The hydrogen produced in the hydrogen production unit is then introduced into the gas distribution structure. The desorbed gas obtained from the hydrogen production unit can be used as fuel gas. The semi-coke generated by the pyrolysis reaction is cooled by the cooling structure and then enters the discharge hopper structure.
[0014] In some specific designs, the pressure inside the pyrolysis reactor is 0.2 MPa-9.0 MPa; the temperature inside the pyrolysis reactor is 200℃-800℃. The temperature of the hydrogen gas flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the flow rate of the hydrogen gas is 5%-50% of the weight of the fine coal, and the hydrogen content in the hydrogen gas flow is 30v%-99v%. The temperature of the gas flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the flow rate of the gas flow is 10%-60% of the weight of the fine coal, and the hydrogen content in the gas flow is 15v%-60v%. The temperature of the steam flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the steam flow rate accounts for 10%-70% of the weight of the fine coal, and the steam content is 30v%-100v%. The temperature of the semi-coke was lowered to below 300℃.
[0015] The present invention achieves the following technical effects compared to the prior art: This invention pressurizes the pyrolysis reactor using a pressurization structure. Under pressurization and in a hydrogen atmosphere, the coal tar yield is significantly increased, and the properties of the coal tar are improved. The generated coal gas is essentially nitrogen-free and has a high calorific value. Due to the pressurization, the volume of the raw coal gas in the pyrolysis reactor is reduced, the linear velocity is significantly decreased, and the escape of fine powder is greatly reduced. Furthermore, pressurization can significantly increase the throughput and reduce energy consumption. In addition, this invention employs a stratified gas inlet method, which can reduce bed pressure drop and improve gas distribution uniformity. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of a low-rank coal pressurized pyrolysis device in some embodiments of the present invention; In the diagram: 1-Top hopper structure, 2-Feed hopper structure, 3-Pyrolysis reactor, 4-Discharge hopper structure, 5-Fracturing tower, 6-Gas-liquid separator, 7-Hydrogen production unit, 8-Top hopper body, 9-Agitator, 10-Heating structure, 11-First control valve, 12-Second control valve, 13-Temperature regulation structure, 14-Gas collection assembly, 15-Gas distribution assembly, 16-Guide step, 17-Cooling structure, 18-Third control valve, 19-Fourth control valve, 20-Condenser, 21-Compressor. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] The purpose of this invention is to provide a low-rank coal pressurized pyrolysis device and method to solve the problems existing in the prior art, thereby increasing the yield of coal tar, increasing the calorific value of coal gas, and reducing energy consumption.
[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0021] Example 1 like Figure 1As shown, this embodiment provides a low-rank coal pressurized pyrolysis device, including: a top hopper structure 1, a feed hopper structure 2, a pyrolysis reactor 3, a discharge hopper structure 4, a fractionation tower 5, a gas-liquid separator 6, and a hydrogen production device 7. The top hopper structure 1, feed hopper structure 2, pyrolysis reactor 3, and discharge hopper structure 4 are arranged from top to bottom and connected sequentially. The upper end of the pyrolysis reactor 3 is provided with a feed inlet, and the lower end of the pyrolysis reactor 3 is provided with a discharge outlet. The pyrolysis reactor 3 is connected to a pressurization structure, which is used to regulate the pressure inside the pyrolysis reactor 3. The pyrolysis reactor 3 is provided with a gas collection structure, a gas distribution structure, and a cooling structure 17 arranged from top to bottom. The gas distribution structure is used to introduce gas into the reactor. The heat medium and gas collection structure are used to collect the gas. The gas collection structure is connected to the fractionation tower 5, which is connected to the gas-liquid separator 6. The gas-liquid separator 6 is connected to the gas distribution structure and the hydrogen production unit 7. A portion of the coal gas obtained from the gas-liquid separator 6 is pressurized by the compressor 21. A portion of the pressurized coal gas can be introduced into the gas distribution structure, or it can be left unintroduced. A valve can be installed on the pipeline between the gas-liquid separator 6 and the gas distribution structure. When pressurized coal gas needs to be introduced, the valve opens; when not, the valve closes. The other portion enters the hydrogen production unit 7. The hydrogen obtained from the hydrogen production unit 7 is used to introduce hydrogen into the gas distribution structure. The desorbed gas and other gases obtained from the hydrogen production unit 7 can be used as fuel gas. In this embodiment, the material is low-rank coal. The low-rank coal moves downwards from the top hopper structure 1 by its own weight, passing sequentially through the feed hopper structure 2, the pyrolysis reactor 3, and the discharge hopper structure 4. Low-rank coal enters pyrolysis reactor 3 and moves downwards by gravity, where it reacts countercurrently with the incoming heat medium. The resulting semi-coke exits from the bottom of pyrolysis reactor 3 and is discharged through hopper structure 4. The generated oil and gas exit from the top of pyrolysis reactor 3 and enter fractionation tower 5, gas-liquid separator 6, and hydrogen production unit 7. Heavy coal tar exits from the bottom of fractionation tower 5, while the gas from the top of fractionation tower 5 passes through gas-liquid separator 6. From gas-liquid separator 6, product light coal tar, product coal gas, and wastewater exit. A portion of the coal gas is pressurized, and part of the pressurized coal gas is recycled back to pyrolysis reactor 3. The remaining pressurized coal gas passes through hydrogen production unit 7 to obtain hydrogen, which is then recycled back to pyrolysis reactor 3. In this embodiment, the pyrolysis reactor 3 is pressurized using a pressurization structure. Under pressurization and in a hydrogen atmosphere, the coal tar yield is significantly increased, and the properties of the coal tar improve. The generated coal gas is essentially nitrogen-free and has a high calorific value. Due to the pressurization, the volume of raw coal gas in pyrolysis reactor 3 is reduced, the linear velocity is significantly decreased, and the escape of fine powder is greatly reduced. Furthermore, pressurization can significantly increase throughput and reduce energy consumption. In addition, this embodiment employs a stratified gas inlet method, which can reduce bed pressure drop and improve gas distribution uniformity.
[0022] In some specific embodiments, the particle size of the low-rank coal is <60mm, preferably fully screened particles smaller than 30mm.
[0023] In some specific embodiments, the top silo structure 1 includes a top silo body 8, an agitator 9, and a heating structure 10. The agitator 9 is located in the top silo body 8, and the heating structure 10 is used to heat the material in the top silo body 8. The heating structure 10 is a steam dryer, the top silo body 8 is an atmospheric pressure vessel, and the steam dryer is a tubular steam condensation heating type. The steam pressure in the heating structure 10 is 0.1MPa~2.0MPa. After drying, the low-rank coal has a water content of <10%, preferably <5%, and a temperature greater than 60℃. In this embodiment, the top silo body 8, in addition to storing raw coal, also functions as a dryer. A tubular steam drying method is used, where low-pressure steam condenses into water in the tubes, releasing heat, which is then transferred to the raw coal to achieve the drying of the low-rank coal. Because it is an external heating method, the dried low-rank coal contains almost no inert gases such as nitrogen and carbon dioxide, ensuring that the low-rank coal entering the pyrolysis reactor 3 does not carry additional inert gases.
[0024] In some specific embodiments, a first control valve 11 is provided between the feed hopper structure 2 and the top hopper structure 1, and a second control valve 12 is provided between the feed hopper structure 2 and the pyrolysis reactor 3. Low-rank coal passes through the feed hopper structure 2 and, according to the depressurization feeding and pressurization discharging method, enters the pyrolysis reactor 3 intermittently by gravity through the first control valve 11 and the second control valve 12. Feeding is performed 2-10 times per hour, preferably 3-5 times per hour.
[0025] In some specific embodiments, the pyrolysis reactor 3 is equipped with a temperature regulating structure 13, which is used to regulate the temperature of the pyrolysis reactor 3. The temperature regulating structure 13 is a water-cooled jacket located outside the pyrolysis reactor 3. Both the pyrolysis reactor 3 and the water-cooled jacket are made of steel, and steam is generated inside the water-cooled jacket. Alternatively, the inner wall of the pyrolysis reactor 3 is provided with a refractory layer or a high-temperature resistant layer, and the pyrolysis reactor 3 uses a steel shell, with the reaction pressure borne by the steel shell. The initial heat of the pyrolysis reactor 3 is provided by a heat medium. At temperatures above 500°C, the material (raw coal) undergoes a pyrolysis reaction in the heat medium atmosphere. This reaction is exothermic. As the reaction proceeds, the temperature of the pyrolysis reactor 3 will increase. In order to control the reaction to maintain a relatively constant temperature for a certain period of time, cold water is introduced into the water-cooled jacket to cool the pyrolysis reactor 3, thereby regulating the temperature of the pyrolysis reactor 3. After the pyrolysis reaction is completed, the pyrolysis reactor 3 also needs to be cooled by the water-cooled jacket to prepare for the next feeding reaction.
[0026] In some specific embodiments, the pyrolysis reactor 3 is a vertical cylindrical shape. The inner diameter of the pyrolysis reactor 3 is 2m to 6m, preferably 3m to 5m; the height-to-diameter ratio of the pyrolysis reactor 3 is 1.5:1 to 6:1, preferably 2:1 to 4:1; the gap width of the water-cooled jacket is 20mm to 200mm, preferably 50mm to 150mm. This embodiment adopts a vertical cylindrical shape and uses an inner refractory or high-temperature resistant layer, or a water-cooled jacket, which solves the problem of high-pressure resistance of the pyrolysis reactor 3 at high temperatures, enabling pressurized operation, and even high-pressure operation. Under certain pressure and suitable temperature, hydrogen can play a role.
[0027] In some specific embodiments, the pyrolysis reactor 3 consists of a drying section, a pyrolysis section, and a cooling section from top to bottom. The temperature of the drying section is 100℃~180℃, the temperature of the pyrolysis section is 500℃~800℃, and the temperature of the cooling section is 250℃~300℃. The temperature inside the pyrolysis reactor 3 is controlled by adjusting the feed rates of raw coal and heat medium, and by adjusting the temperature regulating structure 13.
[0028] In some specific embodiments, the heat transfer medium includes at least hydrogen and steam, or a mixture of hydrogen and steam. More specifically, the heat transfer medium also includes coal gas or a mixture of hydrogen, steam, and coal gas. The heat transfer medium enters the pyrolysis reactor 3 in one to five layers, preferably two to three layers. When the heat transfer medium enters the pyrolysis reactor 3 in one layer, the heat transfer medium is a mixture of hydrogen and steam, or a mixture of hydrogen, steam, and coal gas. When the heat transfer medium enters the pyrolysis reactor 3 in two layers and the heat transfer medium is hydrogen and steam, the upper layer is steam and the lower layer is hydrogen. When the heat transfer medium enters the pyrolysis reactor 3 in three layers and the heat transfer medium is hydrogen, steam is the upper layer, coal gas is the middle layer, and hydrogen is the lower layer; that is, the less dense heat transfer medium is at the bottom and the more dense heat transfer medium is at the top, so as to make the heat transfer medium more uniformly mixed.
[0029] Accordingly, in some specific embodiments, the gas distribution structure is at least one gas distribution component 15, which is used to introduce a mixture of hydrogen and steam or a mixture of hydrogen, steam and coal gas.
[0030] In some specific embodiments, the gas distribution structure includes at least two gas distribution components 15, which are a steam distribution component and a hydrogen distribution component, respectively. The steam distribution component is used to introduce steam, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component is located above the hydrogen distribution component.
[0031] In some specific embodiments, the gas distribution structure includes at least three gas distribution components 15, which are heat medium distributors. The at least three gas distribution components 15 are a steam distribution component, a coal gas distribution component, and a hydrogen distribution component. The steam distribution component is used to introduce steam, the coal gas distribution component is used to introduce coal gas, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component, the coal gas distribution component, and the hydrogen distribution component are arranged from top to bottom. The hydrogen flow, the coal gas flow, and the steam flow each enter the pyrolysis section of the reactor through their respective gas distribution components 15.
[0032] In some embodiments, the gas collection structure includes at least two gas collection components 14 arranged from top to bottom. The gas collection components 14 are preferably gas collection umbrella distributors. Hydrogen gas flow, coal gas flow, and steam flow, along with the gas generated from coal pyrolysis, together form crude coal gas that rises to the upper part of the pyrolysis reactor 3, distributed in 1 to 4 layers, preferably 3 layers. The gas is then uniformly collected from the coal seam by the gas collection components 14 and discharged from the pyrolysis reactor 3 via a side stream.
[0033] In this embodiment, the hydrogen in the coal gas stream and hydrogen gas stream not only stabilizes the primary pyrolysis free radicals but also promotes coal pyrolysis. Hydrogen or hydrogen free radicals act on the macromolecular structure of coal, inducing chemical bond breakage and generating more free radical fragments. Free radicals generated by pyrolysis combine with hydrogen free radicals during their escape, inhibiting the condensation polymerization between free radical fragments and increasing tar yield. Some macromolecular structures in the volatile products undergo hydrogenation and cracking to generate small-molecule tar components or further cracking to generate small-molecule gaseous hydrocarbons. Simultaneously, hydrogen attacks the side chains attached to the aromatic ring, promoting the breaking or removal of aromatic ring side chains and improving tar quality. The presence of hydrogen has a relatively small promoting effect on the formation of phenolic compounds, but is more conducive to the formation of aromatic compounds. At the same time, hydrogen promotes the removal of alkyl side chains from the aromatic ring, which is beneficial to the formation of light coal tar.
[0034] In some specific embodiments, guide steps 16 are provided between the gas distribution structure and the gas collection structure, and between adjacent gas collection components 14. The adjacent guide steps 16 are staggered to allow the airflow to flow upward evenly and stably.
[0035] In some specific embodiments, the cooling structure 17 is connected to a water-cooled jacket, and the cooling structure 17 adopts a tube-and-tube water-cooled heat extraction method. The semi-coke from the pyrolysis section enters the cooling section where the cooling structure 17 is located, and after passing through the cooling section, the temperature of the semi-coke drops to below 300°C.
[0036] Low-rank coal is intermittently added from the top feed inlet of pyrolysis reactor 3, moving downwards by gravity and contacting countercurrently with steam, coal gas, and hydrogen moving upwards. The low-rank coal passes sequentially through the drying section, pyrolysis section, and cooling section in pyrolysis reactor 3 from top to bottom. The resulting semi-coke product is intermittently discharged from the bottom outlet of pyrolysis reactor 3. The generated pyrolysis gas is discharged in stratification from the upper side of pyrolysis reactor 3 to the fractionation tower 5.
[0037] In some specific embodiments, a third control valve 18 is provided between the discharge hopper structure 4 and the pyrolysis reactor 3, and a fourth control valve 19 is provided at the outlet of the discharge hopper structure 4. Semi-coke passes through the discharge hopper structure 4 and is discharged intermittently by gravity via the third control valve 18 and the fourth control valve 19, following a pressurized feeding and depressurized discharge method. Semi-coke is discharged 2-10 times per hour, preferably 3-5 times.
[0038] In this embodiment, the pyrolysis reactor 3 is fed with coal and discharged semi-coke by using a feed hopper structure 2 and a discharge hopper structure 4. The intermittent operation method is used, with coal being fed into the hopper one hopper at a time and semi-coke being discharged one hopper at a time. During the feeding and discharging of coal and semi-coke, the pressure of the feed hopper structure 2 and the discharge hopper structure 4 is kept consistent with the reaction pressure, which can ensure that the pressure of the pyrolysis reactor 3 remains stable.
[0039] In some specific embodiments, a condenser 20 is provided between the fractionation tower 5 and the gas-liquid separator 6; a compressor 21 is provided between the gas-liquid separator 6 and the hydrogen production unit 7, and the hydrogen production unit 7 uses PSA (Pressure Swing Adsorption) to produce hydrogen. The crude coal gas discharged from the pyrolysis reactor 3 enters the fractionation tower 5. Heavy coal tar product is discharged from the bottom of the fractionation tower 5, and the gas discharged from the top of the fractionation tower 5 is cooled by the condenser 20 and then enters the gas-liquid separator 6, where coal gas, light coal tar product, and wastewater are separated. Heavy coal tar is heavier than water, and light coal tar is lighter than water; the density of heavy coal tar is 1.15~1.20 g / cm³. 3 The density of light coal tar is 0.85~0.90 g / cm³. 3 The distillation ranges of heavy coal tar and light coal tar are different, with heavy coal tar having a higher range and light coal tar a lower range. A portion of the coal gas is separated and pressurized by compressor 21. Part of the pressurized coal gas is recycled back to pyrolysis reactor 3, while the remainder is processed by hydrogen production unit 7 to obtain hydrogen, which is then recycled back to pyrolysis reactor 3. The desorbed gas obtained from hydrogen production can be used as fuel gas.
[0040] This embodiment uses a heat transfer medium to provide heat and achieve the reaction temperature required for coal pyrolysis. The heat transfer medium consists of steam, coal gas, hydrogen, and mixtures thereof. A stratified gas intake method is used to reduce bed pressure drop and improve gas distribution uniformity. Among the heat transfer mediums, steam has the highest heat capacity and provides most of the heat, while methane, carbon monoxide, and especially hydrogen are used to improve the reaction environment.
[0041] The pyrolysis reactor 3 in this embodiment contains no moving parts. Inside the pyrolysis reactor 3, coal moves downwards by gravity through the guide steps 16, gas collection structure, and gas distribution structure. This eliminates the problem of plant shutdown caused by easy damage to moving parts.
[0042] In this embodiment, the crude coal gas flows out of the pyrolysis reactor 3 in layers through the gas collecting assembly 14 and directly enters the pressurized fractionation tower 5. The high-temperature heat of the crude coal gas is directly transferred to the coal tar. The heavy coal tar at the bottom of the fractionation tower 5 is recycled to the steam generator, where the heat of the coal gas is converted into steam heat energy. The steam generated by the steam generator is used to feed into the pyrolysis reactor 3.
[0043] In this embodiment, the gas exiting from the distillation tower 5 contains steam, oil gas, and coal gas. After being cooled by the condenser 20 (air cooler and / or water cooler), the gas enters the gas-liquid separator 6 together. The steam becomes liquid water, and the oil gas becomes liquid light coal tar. The gas and liquid are naturally separated and stratified in the gas-liquid separator 6. Coal gas exits from the top of the gas-liquid separator 6, light coal tar exits from the middle of the gas-liquid separator 6, and wastewater exits from the bottom of the gas-liquid separator 6.
[0044] In this embodiment, a portion of the coal gas exiting the gas-liquid separator 6 is used as a product exit device, while a large portion enters the compressor 21 to increase the pressure by approximately 0.2 MPa. A portion of the pressurized coal gas is directly circulated to the coal gas furnace for heating and then enters the pyrolysis reactor 3. Another portion is fed into the hydrogen production device 7 for hydrogen production. The resulting hydrogen is circulated to the hydrogen furnace for heating and then enters the pyrolysis reactor 3.
[0045] In this embodiment, the hydrogen production unit 7 employs pressure swing adsorption (PSA). The coal gas first undergoes temperature swing adsorption (TSA) to remove tar, hydrogen sulfide, ammonia, and other impurities, and then undergoes PSA to produce hydrogen. The permeate gas is hydrogen, and its concentration can be adjusted according to production needs. Generally, the hydrogen concentration is above 80%, and the optimized concentration is above 90%. The PSA-extracted gas can be further processed in other units or used as fuel gas for boilers.
[0046] The pyrolysis reactor 3 in this embodiment can achieve pressurization, hydrogenation, stratified heating medium feeding, and stratified coal gas extraction. Pressurized pyrolysis reduces overall energy consumption. Furthermore, pressurization allows for a smaller equipment size, increasing the processing capacity of a single pyrolysis reactor 3. The volume of raw coal gas in the pyrolysis reactor 3 is reduced, the linear velocity is significantly decreased, and the escape of fine powder is greatly reduced. This embodiment employs stratified feeding of the heating medium, specifically separate stratified feeding of steam, coal gas, and hydrogen. Utilizing the high heat capacity of steam, it provides the main heat for coal pyrolysis and opens up the internal pores of the coal. The methane, carbon monoxide, and hydrogen in the coal gas improve the reaction atmosphere, and the hydrogen atmosphere increases the yield of coal tar and methane. This embodiment achieves a high coal tar yield and improved coal tar properties.
[0047] Example 2 This embodiment provides a method for pressurized pyrolysis of low-rank coal using a low-rank coal pressurized pyrolysis device, including: The material enters the top hopper structure 1 and is dried in the top hopper structure 1; The dried material enters the feed hopper and then enters the pyrolysis reactor 3; Air is discharged from pyrolysis reactor 3. Steam, coal gas, and hydrogen are introduced into pyrolysis reactor 3 through a gas distribution structure. Pyrolysis reactor 3 is heated. After the steam, coal gas, and hydrogen react with the materials, the generated gas is collected through a gas collection structure and enters fractionation tower 5. Heavy coal tar is obtained through fractionation in fractionation tower 5. The gas obtained from fractionation in fractionation tower 5 enters gas-liquid separator 6. After passing through gas-liquid separator, wastewater, light coal tar, and coal gas are obtained. Part of the coal gas is used as a product, and the remaining coal gas is pressurized and enters hydrogen production unit, or part of the pressurized coal gas is returned to gas distribution structure and introduced into pyrolysis reactor 3. The remaining pressurized coal gas enters hydrogen production unit 7. Hydrogen is obtained from hydrogen production unit 7 and is introduced into pyrolysis reactor 3 through gas distribution structure. The desorbed gas and other gases obtained from hydrogen production can be used as fuel gas. The semi-coke produced by the reaction of raw coal in the pyrolysis section of pyrolysis reactor 3 is cooled to below 300℃ in the cooling section of pyrolysis reactor 3 and then enters the discharge hopper structure 4.
[0048] In some specific embodiments, the pressure inside the pyrolysis reactor 3 is 0.2 MPa-9.0 MPa, preferably 1.5-7.0 MPa; the temperature inside the pyrolysis reactor 3 is 200℃-800℃. The temperature of the hydrogen gas stream is 500℃-800℃, preferably 550℃-700℃; the flow rate of the hydrogen gas stream accounts for 5%-50% of the weight of the fine coal, preferably 10%-30%; the hydrogen content in the hydrogen gas stream is 30v%-99v%, preferably 80v%-95v%. The temperature of the gas stream is 500℃-800℃, preferably 550℃-650℃; the flow rate of the gas stream is 10%-60% of the weight of the fine coal, preferably 20%-40%; the hydrogen content in the gas stream is 15v%-60v%, preferably 25v%-45v%. The temperature of the steam stream is 500℃-800℃, preferably 550℃-650℃; the steam flow rate accounts for 10%-70% of the weight of the fine coal, preferably 30%-50%; the steam content in the steam is 30v%-100v, preferably 80v%-95v.
[0049] This embodiment provides a low-rank coal pressurized pyrolysis method using a low-rank coal pressurized pyrolysis device. Compared with conventional pyrolysis processes, this method can produce coal gas with higher calorific value and coal tar of better quality and in greater quantity. Compared with conventional coal pyrolysis processes, this embodiment has lower overall energy consumption, a larger single pyrolysis reactor capacity, higher hydrogen and methane content in the coal gas, higher coal tar yield, and higher light coal tar content. The maximum reaction pressure in this embodiment reaches 6.0 MPa, and the maximum temperature reaches 800℃.
[0050] Application examples A fixed-bed pilot-scale device was used. The pyrolysis reactor 3 was made of 310S steel with an inner diameter of 50 mm and a coal loading height of 200 mm. An electric heating furnace was used to simulate the temperature of the heat medium. The pyrolysis reactor 3 operated intermittently, involving coal loading, heating, cooling to unload semi-coke, collecting gas-liquid-solid samples, and then reloading coal for the next experiment. Hydrogen and steam were mixed and introduced into the reactor; the steam was generated by water vaporization.
[0051] The low-rank coal was sourced from Naomohu Lake in Hami, Xinjiang. The raw coal was appropriately crushed and screened, and 100-2 mesh crushed coal was taken and air-dried naturally. 400 grams of crushed coal were taken and loaded into pyrolysis reactor 3. 2mm ceramic balls were filled both above and below the crushed coal, i.e., ceramic balls, crushed coal, ceramic balls from top to bottom. The reactor was sealed and tested for leaks with nitrogen.
[0052] Nitrogen gas is introduced into pyrolysis reactor 3 at a rate of 1 L / min to raise the temperature and pressure. After the temperature in pyrolysis reactor 3 reaches 200℃ and the pressure reaches 2 MPa, water is introduced into the steam generator at a rate of 100 g / h. The water is converted into steam and introduced into pyrolysis reactor 3. The nitrogen gas is then switched to hydrogen gas. The liquid is collected in the gas-liquid separator 6 using the ice bath method. The temperature of pyrolysis reactor 3 continues to rise at a rate of 2℃ / min. After reaching 600℃, the temperature is stabilized at 600℃ for 3 hours. Then, the temperature is lowered using cooling structure 17. When the temperature of pyrolysis reactor 3 drops to 400℃, the water supply to the steam generator is stopped. When the temperature of pyrolysis reactor 3 drops to 300℃, the hydrogen supply is stopped. The semi-coke is unloaded at room temperature and weighed. Coal tar and water are separated from the liquid and weighed.
[0053] Comparative Example A fixed-bed pilot-scale apparatus was used. The pyrolysis reactor 3 was made of 310S steel, with an inner diameter of 50 mm and a coal loading height of 200 mm. Temperature was controlled by an electric heater. The pyrolysis reactor 3 operated intermittently, involving coal loading, heating, reaction, cooling to unload semi-coke, collection of gas-liquid-solid samples, and reloading for the next experiment. Only nitrogen gas was introduced; water and hydrogen were not introduced.
[0054] The low-rank coal was sourced from Naomohu Lake in Hami, Xinjiang. The raw coal was appropriately crushed and screened, and 100-2 mesh crushed coal was taken and air-dried naturally. 400 grams of crushed coal were taken and loaded into pyrolysis reactor 3, filled with 2mm ceramic balls at the top and bottom, sealed, and tested for leaks with nitrogen.
[0055] Nitrogen gas is introduced into pyrolysis reactor 3 at a rate of 1 L / min to raise the temperature and pressure. After the temperature in pyrolysis reactor 3 reaches 200℃ and the pressure reaches 2 MPa, nitrogen gas is continued to be introduced. Liquid is collected in gas-liquid separator 6 using the ice bath method. The temperature of pyrolysis reactor 3 is further raised at a rate of 2℃ / min until it reaches 600℃. The temperature is then stabilized at 600℃ for 3 hours, and then cooled. Semi-coke is unloaded at room temperature and weighed. Coal tar and water are separated from the liquid and weighed.
[0056] The table below shows the parameters of the raw coal for the application examples and comparative examples.
[0057] Raw coal parameter table
[0058] Comparative experiments showed that under hydrogen and steam atmospheres, the semi-coke yield was 52%, the coal tar yield was 18%, and the coal tar density was 0.922 g / cm³. 3 Under nitrogen atmosphere, the yield of semi-coke was 53.8%, the coal tar yield was 9.6%, and the coal tar density was 0.935 g / cm³. 3 The properties of coal tar improve, its density decreases, and its light components increase. Therefore, this embodiment, by pyrolyzing low-rank coal in a hydrogen atmosphere under certain temperature and pressure, can produce more coal tar with better quality, and the methane content in the coal gas is also significantly increased.
[0059] In the description of this invention, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0060] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0061] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws) or a non-detachable fixed connection (e.g., riveting, welding). Of course, a fixed connection can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).
[0062] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.
[0063] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.
[0064] It should be noted that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read them, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.
[0065] It should also be noted that in the embodiments of this application, the same reference numerals are used to denote the same component or the same part.
[0066] Any adaptive changes made according to actual needs are within the scope of protection of this invention.
[0067] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.
Claims
1. A pressurized pyrolysis device for low-rank coal, characterized in that: include: The system comprises a top hopper structure, a feed hopper structure, a pyrolysis reactor, a discharge hopper structure, a fractionating tower, a gas-liquid separator, and a hydrogen production unit. These structures are arranged from top to bottom and connected sequentially. The pyrolysis reactor has a feed inlet at its upper end and a discharge outlet at its lower end. The reactor is connected to a pressurizing structure for regulating the internal pressure. Inside the reactor, from top to bottom, are a gas collecting structure, a gas distribution structure, and a cooling structure. The gas distribution structure introduces a heat medium, and the gas collecting structure collects gas. The gas collecting structure is connected to the fractionating tower, which is connected to the gas-liquid separator. The gas-liquid separator is connected to both the gas distribution structure and the hydrogen production unit. The hydrogen production unit is connected to the gas distribution structure. The gas-liquid separator produces coal gas, and the hydrogen production unit produces hydrogen.
2. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: The top hopper structure includes a top hopper body, an agitator, and a heating structure. The agitator is located in the top hopper body, and the heating structure is used to heat the material in the top hopper body.
3. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: A first control valve is provided between the feed hopper structure and the top hopper structure, and a second control valve is provided between the feed hopper structure and the pyrolysis reactor. A third control valve is provided between the discharge hopper structure and the pyrolysis reactor, and a fourth control valve is provided at the outlet of the discharge hopper structure.
4. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: The pyrolysis reactor is equipped with a temperature regulating structure for regulating the temperature of the pyrolysis reactor; or, the inner wall of the pyrolysis reactor is provided with a refractory layer or a high-temperature resistant layer.
5. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: The gas collection structure includes at least two gas collection components arranged from top to bottom.
6. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: The gas distribution structure includes at least two gas distribution components, namely a steam distribution component and a hydrogen distribution component. The steam distribution component is used to introduce steam, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component is located above the hydrogen distribution component.
7. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: The gas distribution structure includes at least three gas distribution components, namely a steam distribution component, a coal gas distribution component, and a hydrogen distribution component. The steam distribution component is used to introduce steam, the coal gas distribution component is used to introduce coal gas, and the hydrogen distribution component is used to introduce hydrogen. The steam distribution component, the coal gas distribution component, and the hydrogen distribution component are arranged from top to bottom.
8. The low-rank coal pressurized pyrolysis apparatus according to claim 1, characterized in that: A condenser is provided between the fractionation tower and the gas-liquid separator; a compressor is provided downstream of the gas-liquid separator, and the coal gas obtained from the gas-liquid separator is pressurized by the compressor and can be introduced into the gas distribution structure and the hydrogen production device.
9. A method for pressurizing low-rank coal using a pressurized pyrolysis apparatus as described in any one of claims 1-8, characterized in that: include: The material enters the top hopper structure and is dried there. The dried material enters the feed hopper and then enters the pyrolysis reactor; A heat medium is introduced into the pyrolysis reactor through a gas distribution structure. After the heat medium interacts with the material, the generated gas is collected through a gas collection structure and enters a fractionation tower. In the fractionation tower, heavy coal tar is obtained at the bottom of the tower. The gas obtained from fractionation enters a gas-liquid separator, which produces wastewater, light coal tar, and coal gas. A portion of the coal gas is used as a product, while the remaining coal gas is pressurized and enters a hydrogen production unit, or it can be returned to the gas distribution structure and enter the hydrogen production unit simultaneously. The hydrogen produced in the hydrogen production unit is then introduced into the gas distribution structure. The desorbed gas obtained from the hydrogen production can be used as fuel gas. The semi-coke generated by the pyrolysis reaction is cooled by the cooling structure and then enters the discharge hopper structure.
10. The method for pressurized pyrolysis of low-rank coal according to claim 9, characterized in that: The pressure inside the pyrolysis reactor is 0.2 MPa-9.0 MPa; the temperature inside the pyrolysis reactor is 200℃-800℃. The temperature of the hydrogen gas flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the flow rate of the hydrogen gas is 5%-50% of the weight of the fine coal, and the hydrogen content in the hydrogen gas flow is 30v%-99v%. The temperature of the gas flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the flow rate of the gas flow is 10%-60% of the weight of the fine coal, and the hydrogen content in the gas flow is 15v%-60v%. The temperature of the steam flow in the heat medium introduced into the gas distribution structure is 500℃-800℃, the steam flow rate accounts for 10%-70% of the weight of the fine coal, and the steam content is 30v%-100v%. The temperature of the semi-coke was lowered to below 300℃.