Electric heating semi-coke oven for destructive distillation of low-order pulverized coal and destructive distillation method of low-order pulverized coal

Abstract

The invention relates to an electric heating semi-coke oven for destructive distillation of low-order pulverized coal and a destructive distillation method of the low-order pulverized coal. The electric heating semi-coke oven comprises a coal feeding system, a semi-coke oven and a coke discharging system which are sequentially connected from top to bottom, a plurality of carbonization chambers and electric heating chambers are arranged in a furnace body of the semi-coke furnace at intervals, the electric heating chambers are arranged on two sides of each carbonization chamber, and electric heating devices are arranged in the electric heating chambers; a plurality of temperature measuring openings are formed in the furnace wall of the semi-coke furnace and used for mounting temperature measuring devices, and the electric heating devices and the temperature measuring devices are in interlocking control; the coal feeding system is of a double-bin double-valve structure. The semi-coke oven provided by the invention adopts green electricity to provide a heat source and is energy-saving and pollution-free, the temperature of the dry distillation area is accurately controlled, and materials are uniformly heated; a plurality of carbonization chambers share one set of coal feeding system and coke discharging system, so that the investment cost is reduced; and the coal feeding system adopts a double-bin double-valve structure, so that coal gas can be effectively prevented from escaping, and the environmental protection property is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-rank coal dry distillation, and in particular to an electric heating semi-coke oven for low-rank pulverized coal dry distillation and a low-rank pulverized coal dry distillation method. Background Art

[0002] Low-rank coal dry distillation technology is a process that converts low-rank coal (such as lignite, long flame coal, and non-caking coal) into semi-coke, coal tar, and coal gas through medium- and low-temperature pyrolysis (500-800°C). This technology significantly increases the resource value of low-rank coal, enabling graded utilization while reducing pollution from direct combustion.

[0003] Low-rank pulverized coal (low-rank coal powder with a particle size of less than 3mm) has low efficiency and high pollution when used directly due to its high moisture content, high volatile matter, and low calorific value. It can be converted into high-value-added products through distillation, gasification, molding and other technologies. For example, semi-coke can be used for calcium carbide, ferroalloys, civilian fuel, etc., tar can be further processed to produce fuel oil or chemical raw materials, and coal gas can be used as fuel or synthesis gas, thereby achieving efficient utilization of resources.

[0004] Semi-coke ovens are categorized as internally heated, externally heated, and moving / fluidized bed. Low-rank coal powder dry distillation typically utilizes internally heated semi-coke ovens, which typically use hot flue gas as their heat source. For example, Chinese patent application publication number CN116004263A discloses a "circular semi-coke oven for high-temperature pyrolysis of low-rank coal." The oven consists of several independent gasifiers arranged in a rectangular array, with multiple rows arranged in two rows. Conveyor mechanisms are located at the top and bottom of each gasifier's feed bin. A vibrating screen is installed in the feed bin, allowing undersize material to enter the gasifier while oversize material is transported to the outside via a conveyor mechanism at the top. A discharge port at the bottom of each gasifier discharges material to a conveyor mechanism at the bottom for unified external transport. Each gasifier is equipped with a gas collection pipe, which is connected to a main gas collection pipe to deliver the collected gas to a gas purification system. The heat required for ignition is generated by the direct combustion of an oxygen-enriched gasifier and the coal within the furnace. When the pyrolysis temperature reaches 1200°C, hot flue gas rises. When the temperature exceeds 850°C, the upper coal is dry-distilled, forming semi-coke and generating some producer gas. Since tar is the primary pyrolysis product of coal at temperatures between 550°C and 850°C, a softened water pipe is installed for heat exchange, allowing the medium-temperature dry distillation chamber to be controlled between 350°C and 550°C for pyrolysis.

[0005] Traditional internally heated semi-coke ovens have poor production stability, the temperature in the distillation zone is difficult to control, and they are less environmentally friendly. Summary of the Invention

[0006] The present invention provides an electrically heated semi-coke oven and a dry distillation method for dry distillation of low-rank pulverized coal. The semi-coke oven uses green electricity to provide a heat source, is energy-saving and pollution-free, has precise temperature control in the dry distillation zone, and heats the material evenly. Multiple carbonization chambers share a set of coal feeding and coke removal systems, reducing investment costs. The coal feeding system adopts a double-bin double-valve structure, which can effectively prevent gas leakage and improve environmental protection.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] An electrically heated semi-coke oven for dry distillation of low-rank pulverized coal comprises a coal feeding system, a semi-coke oven and a coke discharge system connected in sequence from top to bottom; a plurality of carbonization chambers and electric heating chambers are alternately arranged in the furnace body of the semi-coke oven, an electric heating chamber is provided on both sides of each carbonization chamber, and an electric heating device is installed in the electric heating chamber; a plurality of temperature measuring ports are provided on the furnace wall of the semi-coke oven for installing temperature measuring devices, and the electric heating device and the temperature measuring device are interlocked for control; the coal feeding system adopts a double-bin double-valve structure.

[0009] A gas outlet is provided at the center of the top of the carbonization chamber, and several feed ports are provided around the gas outlet; the feeding system consists of an upper coal bunker, a first coal discharge valve, a lower coal bunker, a second coal discharge valve and a coal discharge chute; the discharge port at the bottom of the upper coal bunker is connected to the feed port at the top of the lower coal bunker through the first coal discharge valve, and the discharge port at the bottom of the lower coal bunker is connected to the feed port of the coal discharge chute through the second coal discharge valve, and the discharge ports of the coal discharge chute are arranged in one-to-one correspondence with the feed port of the carbonization chamber.

[0010] The gas outlet is connected to the gas purification system through a gas pipeline, and an ammonia spray device is installed in the gas pipeline near the gas outlet; a pressure detection device, a temperature detection device, a flow detection device and a flow regulating valve are installed on the gas pipeline, and the flow regulating valve is interlocked with the pressure detection device and the flow detection device for control.

[0011] The electric heating device includes multiple vertically arranged electric heaters, which are evenly spaced in the electric heating chamber; the electric heaters in the same electric heating device are divided into several groups, and each group of electric heaters is connected to the same temperature control device; each carbonization chamber is equipped with several temperature measuring devices, and the temperature control device is interlocked with the corresponding temperature measuring device for control.

[0012] Each electric heater consists of a ceramic rod and an electric heating wire wound around the ceramic rod.

[0013] A refractory material layer is provided between the electric heating chamber and the carbonization chamber.

[0014] The furnace wall of the semi-coke oven consists of a steel structure shell, a refractory brick wall and a heat insulation layer which are arranged in sequence from the outside to the inside.

[0015] A cone bucket is provided at the bottom of each carbonization chamber; the coke discharge system consists of a screw conveyor, a coke discharge bin and a coke discharge valve. The screw conveyor is arranged below the cone bucket along the arrangement direction of the cone bucket. A motor is provided at the driving end of the screw conveyor. The discharge end of the screw conveyor is connected to the feed port at the top of the coke discharge bin. A coke discharge valve is provided at the discharge port at the bottom of the coke discharge bin.

[0016] A method for dry distillation of low-rank coal powder includes the following steps:

[0017] 1) The low-rank pulverized coal delivered by the coal preparation unit enters the upper coal bunker and enters the lower coal bunker through the coal discharge valve 1. Then the coal discharge valve 1 is closed and the coal discharge valve 2 is opened. The low-rank pulverized coal in the lower coal bunker enters the corresponding carbonization chamber through multiple discharge ports of the coal discharge chute, achieving uniform distribution at the same time;

[0018] 2) The low-rank pulverized coal enters the carbonization chamber and moves from top to bottom. The low-rank pulverized coal is heated by electric heating devices in the electric heating chambers on both sides of the carbonization chamber. The low-rank pulverized coal is heated to 340-360°C in the preheating section at the top of the carbonization chamber. The low-rank pulverized coal moves downward to the dry distillation section in the middle of the carbonization chamber and is heated to 650-780°C to form semi-coke. The heating temperatures of the preheating and dry distillation sections are precisely controlled by grouping temperature control of the electric heaters and interlocking control of the electric heating device and the temperature measuring device.

[0019] 3) The semi-coke continues to move downward, passes through the cooling section at the bottom of the carbonization chamber, and is cooled to below 200°C before being discharged from the cone bucket. The semi-coke is continuously transported to the coke discharge bin by the screw conveyor, and then discharged through the coke discharge valve and transported to the subsequent semi-coke cooling system;

[0020] 4) The coal gas generated during the dry distillation of low-rank pulverized coal enters the gas pipeline through the gas outlet, and is cooled to 70-80°C by spraying circulating ammonia water. The cooled coal gas and the condensed ammonia-coal tar mixture enter the gas purification system together; the flow detection device, pressure detection device and flow control valve on the gas pipeline are interlocked and controlled to adjust the pressure and flow of the gas pipeline.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The semi-coke oven uses green electricity as a heat source. Compared with conventional semi-coke ovens that use hot flue gas as a heat source, it is energy-saving and pollution-free, which is conducive to the sustainable development of the industry;

[0023] 2) Through the interlocking control of the electric heating device and the temperature measuring device, the temperature of the distillation zone is accurately controlled. Electric heating devices are evenly distributed on both sides of each carbonization chamber to ensure uniform heating of the material.

[0024] 3) Multiple carbonization chambers share one coal loading device and coke discharge device, and the coal loading device adopts a double-bin double-valve structure, which effectively prevents coal gas from escaping, improves environmental protection, and reduces investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an electrically heated low-rank coal dry distillation semi-coke oven according to the present invention.

[0026] Figure 2 yes Figure 1 AA view in.

[0027] In the figure: 1-upper coal bunker; 2-coal discharge valve 1; 3-lower coal bunker; 4-coal discharge valve 2; 5-coal discharge chute; 6-ceramic rod; 7-electric heater; 8-furnace body; 8.1-carbonization chamber; 8.2-electric heating chamber; 8.3-insulation layer; 8.4-refractory brick wall; 8.5-steel structure shell; 8.6-refractory material layer; 9-cone bucket; 10-screw conveyor; 11-motor; 12-coke discharge bin; 13-coke discharge valve; 14-temperature measuring port; 15-gas outlet. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0029] like Figure 1 、 Figure 2 As shown, the electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to the present invention comprises a coal loading system, a semi-coke oven, and a coke discharge system connected sequentially from top to bottom. A plurality of carbonization chambers 8.1 and electric heating chambers 8.2 are alternately arranged in the furnace body of the semi-coke oven. Each carbonization chamber 8.1 is provided with an electric heating chamber 8.2 on both sides, and an electric heating device is installed in the electric heating chamber 8.2. A plurality of temperature measuring ports 14 are provided on the furnace wall of the semi-coke oven for installing temperature measuring devices, and the electric heating device and the temperature measuring device are interlocked for control. The coal loading system adopts a dual-bin dual-valve structure.

[0030] A gas outlet 15 is provided at the top center of the carbonization chamber 8.1, and several feed ports are provided around the gas outlet 15; the feeding system consists of an upper coal bunker 1, a coal discharge valve 1 2, a lower coal bunker 3, a coal discharge valve 2 4 and a coal discharge chute 5; the discharge port at the bottom of the upper coal bunker 1 is connected to the feed port at the top of the lower coal bunker 3 through a coal discharge valve 1 2, and the discharge port at the bottom of the lower coal bunker 3 is connected to the feed port of the coal discharge chute 5 through a coal discharge valve 2 4, and the discharge ports of the coal discharge chute 5 are arranged in a one-to-one correspondence with the feed ports of the carbonization chamber 8.1.

[0031] The gas outlet 15 is connected to the gas purification system through a gas pipeline. An ammonia spray device is installed in the gas pipeline near the gas outlet 15. A pressure detection device, a temperature detection device, a flow detection device and a flow regulating valve are installed on the gas pipeline. The flow regulating valve is interlocked with the pressure detection device and the flow detection device for control.

[0032] The electric heating device includes a plurality of vertically arranged electric heaters 7, which are evenly spaced within the electric heating chamber 8.2. The electric heaters 7 in the same electric heating device are divided into several groups, and each group of electric heaters is connected to the same temperature control device. Each carbonization chamber 8.1 is equipped with several temperature measuring devices, and the temperature control devices are interlocked with the corresponding temperature measuring devices for control.

[0033] Each electric heater 7 is composed of a ceramic rod and an electric heating wire wound around the ceramic rod.

[0034] A refractory material layer is provided between the electric heating chamber 8.2 and the carbonization chamber 8.1.

[0035] The furnace wall of the semi-coke oven is composed of a steel structure shell 8.5, a refractory brick wall 8.4 and a heat insulation layer 8.3 which are arranged in sequence from the outside to the inside.

[0036] A cone bucket 9 is provided at the bottom of each carbonization chamber 8.1; the coke discharge system consists of a screw conveyor 10, a coke discharge bin 12 and a coke discharge valve 13. The screw conveyor 10 is arranged below the cone bucket 9 along the arrangement direction of the cone bucket 9. The driving end of the screw conveyor 10 is provided with a motor 11. The discharge end of the screw conveyor 10 is connected to the feed port at the top of the coke discharge bin 12. The coke discharge valve 13 is provided at the discharge port at the bottom of the coke discharge bin 12.

[0037] The low-rank coal powder dry distillation method of the present invention comprises the following steps:

[0038] 1) Low-rank pulverized coal delivered by the coal preparation unit enters the upper coal bunker 1 and enters the lower coal bunker 3 through the coal discharge valve 1 2. The coal discharge valve 1 2 is then closed and the coal discharge valve 2 4 is opened. The low-rank pulverized coal in the lower coal bunker 3 enters the corresponding carbonization chamber 8.1 through the multiple discharge ports of the coal discharge chute 5, achieving uniform distribution.

[0039] 2) Low-rank pulverized coal enters carbonization chamber 8.1 and moves downward. Electric heating devices within electric heating chambers 8.2 on either side of carbonization chamber 8.1 heat the low-rank pulverized coal to 340-360°C in the preheating section at the top of carbonization chamber 8.1. The low-rank pulverized coal then moves downward to the dry distillation section in the middle of carbonization chamber 8.1, where it is heated to 650-780°C to form semi-coke. The heating temperatures in the preheating and dry distillation sections are precisely controlled through group temperature control of electric heaters 7 and interlocking control between the electric heating devices and temperature measuring devices.

[0040] 3) The semi-coke continues to move downward, passes through the cooling section at the bottom of the carbonization chamber 8.1, and is cooled to below 200°C before being discharged from the cone bucket 9. The semi-coke is continuously transported to the coke discharge bin 12 by the screw conveyor 10, and then discharged through the coke discharge valve 13 and transported to the subsequent semi-coke cooling system.

[0041] 4) The coal gas generated during the dry distillation of low-rank pulverized coal enters the gas pipeline through the coal gas outlet 15, and is cooled to 70-80°C by spraying circulating ammonia water. The cooled coal gas and the condensed ammonia-coal tar mixture enter the gas purification system together; the flow detection device and pressure detection device on the gas pipeline are interlocked with the flow control valve to adjust the pressure and flow of the gas pipeline.

[0042] The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal described in the present invention mainly comprises a semi-coke oven, a coal feeding system, a coke discharge system and a coal gas exhaust system.

[0043] The semi-coke oven includes multiple carbonization chambers 8.1, which serve as vertical channels for feeding low-grade pulverized coal. Electric heating chambers 8.2 on either side of the carbonization chambers 8.1 house electric heaters connected to an external power source. Temperature measuring ports 14 are provided on the furnace wall for mounting the temperature measuring devices. Interlocking control between the temperature measuring devices and the electric heaters allows precise temperature control within the carbonization chambers 8.1, effectively improving the coke yield.

[0044] The top of carbonization chamber 8.1 is equipped with a feed inlet and a gas outlet 15. The coal loading system features a dual-bin, dual-valve structure to prevent gas leakage. The coke discharge system consists of a screw conveyor 10 and a coke discharge bin 12. A conical hopper 9 is located at the bottom of carbonization chamber 8.1, beneath which a screw conveyor 10 is installed to deliver the retorted semi-coke to the coke discharge bin 12. Multiple carbonization chambers 8.1 share a single coal loading and discharge system, effectively reducing equipment investment costs.

[0045] The core technology of the present invention is the use of electric heating in the semi-coke oven. A carbonization chamber 8.1 and an electric heating chamber 8.2 are separated within the semi-coke oven. An electric heating device is installed within the electric heating chamber 8.2. Using the heat generated by the electric heating device as a heat source, the low-rank pulverized coal is heated more evenly.

[0046] The semi-coke oven can have a square or circular cross-section. Its inner wall is provided with a heat-insulating layer 8.3 made of refractory material. A refractory layer 8.6 is placed between the electric heating chamber 8.2 and the carbonization chamber 8.1. The main body of the electric heater 7 is a ceramic rod that exhibits minimal plasticity change at high temperatures, meaning it is not easily deformed. The electric heating wire is wound around it. The electric heaters 7 are grouped and temperature-controlled to ensure precise temperature control in each section of the carbonization chamber 8.1.

[0047] The gas discharge system installed on the top of the semi-coke oven is mainly composed of a gas pipeline, an ammonia spray device installed in the gas pipeline, and a pressure detection device, temperature detection device, flow detection device and flow control valve installed on the gas pipeline. It is used to smoothly discharge the gas generated in the low-rank coal distillation process to the gas purification system.

[0048] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An electrically heated semi-coke oven for dry distillation of low-rank pulverized coal, comprising a coal feeding system, a semi-coke oven, and a coke discharge system connected in sequence from top to bottom; characterized in that: The semi-coke oven has a furnace body in which a plurality of carbonization chambers and electric heating chambers are arranged alternately. Electric heating chambers are provided on both sides of each carbonization chamber, and electric heating devices are installed in the electric heating chambers. A plurality of temperature measuring ports are provided on the furnace wall of the semi-coke oven for installing temperature measuring devices, and the electric heating devices are interlocked and controlled with the temperature measuring devices. The coal feeding system adopts a double-bin double-valve structure.

2. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 1, wherein: A gas outlet is provided at the center of the top of the carbonization chamber, and several feed ports are provided around the gas outlet; the feeding system consists of an upper coal bunker, a first coal discharge valve, a lower coal bunker, a second coal discharge valve and a coal discharge chute; the discharge port at the bottom of the upper coal bunker is connected to the feed port at the top of the lower coal bunker through the first coal discharge valve, and the discharge port at the bottom of the lower coal bunker is connected to the feed port of the coal discharge chute through the second coal discharge valve, and the discharge ports of the coal discharge chute are arranged in one-to-one correspondence with the feed port of the carbonization chamber.

3. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 2, wherein: The gas outlet is connected to the gas purification system through a gas pipeline, and an ammonia spray device is installed in the gas pipeline near the gas outlet; a pressure detection device, a temperature detection device, a flow detection device and a flow regulating valve are installed on the gas pipeline, and the flow regulating valve is interlocked with the pressure detection device and the flow detection device for control.

4. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 1, wherein: The electric heating device includes multiple vertically arranged electric heaters, which are evenly spaced in the electric heating chamber; the electric heaters in the same electric heating device are divided into several groups, and each group of electric heaters is connected to the same temperature control device; each carbonization chamber is equipped with several temperature measuring devices, and the temperature control device is interlocked with the corresponding temperature measuring device for control.

5. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 4, characterized in that: Each electric heater consists of a ceramic rod and an electric heating wire wound around the ceramic rod.

6. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 1, characterized in that: A refractory material layer is provided between the electric heating chamber and the carbonization chamber.

7. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 1, characterized in that: The furnace wall of the semi-coke oven consists of a steel structure shell, a refractory brick wall and a heat insulation layer which are arranged in sequence from the outside to the inside.

8. The electrically heated semi-coke oven for dry distillation of low-rank pulverized coal according to claim 1, characterized in that: A cone bucket is provided at the bottom of each carbonization chamber; the coke discharge system consists of a screw conveyor, a coke discharge bin and a coke discharge valve. The screw conveyor is arranged below the cone bucket along the arrangement direction of the cone bucket. A motor is provided at the driving end of the screw conveyor. The discharge end of the screw conveyor is connected to the feed port at the top of the coke discharge bin. A coke discharge valve is provided at the discharge port at the bottom of the coke discharge bin.

9. A method for dry distillation of low-rank coal powder, based on the electrically heated semi-coke oven for dry distillation of low-rank coal powder according to any one of claims 1 to 8, characterized in that: The process includes the following: 1) The low-rank pulverized coal delivered by the coal preparation unit enters the upper coal bunker and enters the lower coal bunker through the coal discharge valve 1. Then the coal discharge valve 1 is closed and the coal discharge valve 2 is opened. The low-rank pulverized coal in the lower coal bunker enters the corresponding carbonization chamber through multiple discharge ports of the coal discharge chute, achieving uniform distribution at the same time; 2) The low-rank pulverized coal enters the carbonization chamber and moves from top to bottom. The low-rank pulverized coal is heated by electric heating devices in the electric heating chambers on both sides of the carbonization chamber. The low-rank pulverized coal is heated to 340-360°C in the preheating section at the top of the carbonization chamber. The low-rank pulverized coal moves downward to the dry distillation section in the middle of the carbonization chamber and is heated to 650-780°C to form semi-coke. The heating temperatures of the preheating and dry distillation sections are precisely controlled by grouping temperature control of the electric heaters and interlocking control of the electric heating device and the temperature measuring device. 3) The semi-coke continues to move downward, passes through the cooling section at the bottom of the carbonization chamber, and is cooled to below 200°C before being discharged from the cone bucket. The semi-coke is continuously transported to the coke discharge bin by the screw conveyor, and then discharged through the coke discharge valve and transported to the subsequent semi-coke cooling system; 4) The coal gas generated during the dry distillation of low-rank pulverized coal enters the gas pipeline through the gas outlet, and is cooled to 70-80°C by spraying circulating ammonia water. The cooled coal gas and the condensed ammonia-coal tar mixture enter the gas purification system together; the flow detection device, pressure detection device and flow control valve on the gas pipeline are interlocked and controlled to adjust the pressure and flow of the gas pipeline.

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