Environment-friendly low-rank coal pyrolysis device and process

Abstract

The invention discloses an environment-friendly low-rank coal pyrolysis device and process, the environment-friendly low-rank coal pyrolysis device comprises a pyrolysis furnace and a high and low temperature gas mixing device, the high and low temperature gas mixing device comprises a tank body, a low temperature gas inlet pipe, a high temperature gas inlet pipe and a gas outlet pipe orifice, low temperature gas enters the tank body through the low temperature gas inlet pipe, and the high temperature gas enters the high temperature gas inlet pipe through the gas outlet pipe orifice; a low-temperature adjusting valve is arranged at the end of the low-temperature gas inlet pipe, high-temperature gas enters the tank body through the high-temperature gas inlet pipe, a high-temperature adjusting valve is arranged at the end of the high-temperature gas inlet pipe, a gas outlet pipe opening is formed in the bottom of the tank body and connected with the pyrolyzing furnace, and a moisture detector is arranged on the pyrolyzing furnace. The moisture detector and the low-temperature regulating valve are electrically connected with the high-temperature regulating valve, the opening degree of the two regulating valves is controlled through data of the moisture detector to regulate the mixing proportion of high-temperature gas and low-temperature gas, and the process requirements of raw coal with different moisture contents are met. Raw coal with high water content can be treated, reduction of phenol-ammonia sewage is realized, and the energy-saving property of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of low-rank coal process technology, specifically relating to an environmentally friendly low-rank coal pyrolysis device and process. Background Technology

[0002] my country is a major coal producer. Although its coal reserves are abundant, a high percentage (approximately 58%) is low-rank coal with a low degree of coalification. Low-rank coal has high volatile matter content and high reactivity, indicating significant potential utilization value. Currently, most low-rank coal is directly burned for power generation and other energy-related purposes. However, the combustion of low-rank coal produces large amounts of carbon dioxide, contributing to the greenhouse effect. Furthermore, the oil and gas energy within low-rank coal is not utilized at a high value, resulting in resource waste. A small portion of low-rank coal is used for pyrolysis, converting it into carbon dioxide, tar, and semi-coke, thereby achieving the upgrading and utilization of low-rank coal.

[0003] Low-rank coal pyrolysis technology, particularly gas-based pyrolysis, is relatively mature. While low-rank coal pyrolysis typically employs medium-to-low temperatures, this limits the amount of residual heat generated from the semi-coke. The high-temperature gas used to recover this residual heat can only remove 40%–60% of the water from the raw coal, leaving the remaining moisture in the dry distillation section, thus increasing the total heat required for coal pyrolysis. The removed water is also extracted from the dry distillation section along with the coal gas, increasing the production of raw coal gas and consequently raising the investment costs for gas purification and oil recovery units. Furthermore, the raw coal gas produces phenol and ammonia wastewater, increasing its production and wastewater treatment costs. Therefore, current low-rank coal pyrolysis technologies generally require the moisture content of the raw coal to be less than 20%.

[0004] Current low-rank coal pyrolysis technologies, besides being unable to handle low-rank raw coal with high moisture content, also suffer from poor mixing efficiency and difficulty in achieving sufficient mixing when mixing high-temperature and low-temperature gases, often using direct mixing via three-way pipes. This leads to uneven heating of low-rank raw coal in contact with insufficiently mixed gases, resulting in reduced energy utilization and output, as well as decreased equipment durability. Furthermore, commonly used high- and low-temperature gas mixing devices cannot adjust the mixing ratio of high and low-temperature gases according to the moisture content of low-rank raw coal, and have a low level of automation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an environmentally friendly low-rank coal pyrolysis device and process that can process low-rank coal with high moisture content, significantly reduce the volume of phenol and ammonia wastewater, lower the total heat demand of the system, improve the mixing efficiency and degree of high and low temperature gases, enhance the level of intelligence, and achieve a significant improvement in economic and environmental benefits.

[0006] The present invention adopts the following technical solution.

[0007] This invention discloses an environmentally friendly low-rank coal pyrolysis device, comprising: a pyrolysis furnace and a high- and low-temperature gas mixing device. The high- and low-temperature gas mixing device includes: a tank, a low-temperature gas inlet pipe, a high-temperature gas inlet pipe, and an outlet pipe. Low-temperature gas enters the tank through the low-temperature gas inlet pipe, and a low-temperature regulating valve is installed at the end of the low-temperature gas inlet pipe. High-temperature gas enters the tank through multiple symmetrically arranged high-temperature gas inlet pipes, and a high-temperature regulating valve is installed at the end of the high-temperature gas inlet pipes. An outlet pipe is installed at the bottom of the tank and is connected to the upper part of the pyrolysis furnace. A moisture detector is installed on the pyrolysis furnace to detect the moisture content of the low-rank coal. The moisture detector and the low-temperature regulating valve are electrically connected to the high-temperature regulating valve. The opening degree of the two regulating valves is adjusted according to the moisture content data of the moisture detector to adjust the ratio of high- and low-temperature gases, so as to meet the process requirements of low-rank coal with different moisture contents.

[0008] Preferably, the lower inner wall of the tank is provided with a circular slide rail, and the flow guiding structure is rotatably installed on the circular slide rail. The flow guiding structure is circumferentially arranged with multiple vent holes, and the upper outer wall of the flow guiding structure is uniformly arranged with multiple swirl plates. When high and low temperature gases are mixed, the vortex generated drives the flow guiding structure to rotate along the circular slide rail through the swirl plates.

[0009] Preferably, multiple baffles are staggered on the inner wall of the tank, and the baffles have round holes. The baffles change the direction of the gas, thereby enhancing the mixing degree of high and low temperature gases. A manhole is provided on the left side of the tank for inspection and maintenance.

[0010] Preferably, the pyrolysis furnace is provided with a coal bunker, a drying section, a carbonization section, and a cooling section from top to bottom. A moisture detector is installed on the coal bunker. The outlet of the high and low temperature gas mixing device is connected to the drying section of the pyrolysis furnace via a pipeline. One side of the spray tower is connected to the drying section of the pyrolysis furnace via a pipeline.

[0011] Preferably, the right side of the pyrolysis furnace cooling section is connected in sequence to a cyclone dust collector, a gas induced draft fan, a high and low temperature mixing device, and a pyrolysis furnace drying section via pipes.

[0012] Preferably, the pyrolysis furnace dry distillation section is connected to the gas purification and oil recovery unit, and the right side of the gas purification and oil recovery unit is connected to the sewage treatment unit.

[0013] Preferably, the gas purification and oil recovery unit outputs tar and gas through a pipeline. The gas output pipeline is connected to both the combustion furnace and the heating furnace of the gas heater through a three-way connector. The right side of the dry distillation section of the pyrolysis furnace is also connected to the heating furnace of the gas heater through a pipeline. At the same time, the heating furnace of the gas heater is also connected to the high-temperature gas inlet pipe of the high-low temperature gas mixing device.

[0014] Preferably, one side of the gas heater is connected to a flue gas purification unit via a pipe. The flue gas purification unit is used to purify the flue gas during combustion of the gas heater. At the same time, the combustion furnace and blower of the gas heater are connected to assist the combustion of the gas heater.

[0015] This invention also discloses an environmentally friendly low-rank coal pyrolysis process, based on the aforementioned environmentally friendly low-rank coal pyrolysis device, comprising the following steps:

[0016] Low-rank raw coal is fed into the drying section of the pyrolysis furnace through the coal bunker for heating and dehydration;

[0017] After dehydration, the low-rank raw coal enters the dry distillation section of the pyrolysis furnace for high-temperature heat exchange, and is converted into semi-coke, tar, pyrolysis gas and pyrolysis water;

[0018] The gaseous products, tar, pyrolysis gas and pyrolysis water, enter the gas purification and oil recovery unit for purification and transmission.

[0019] The semi-coke, a solid product, enters the cooling section of the pyrolysis furnace and is cooled by cold gas and condensate from the spray tower (13) to form a semi-coke product. The semi-coke product is output from the bottom of the cooling section of the pyrolysis furnace.

[0020] Preferably, the tar and pyrolysis water are condensed to precipitate an oil-water mixture, which is then allowed to stand and separate into layers to obtain tar and phenol-ammonia wastewater. The phenol-ammonia wastewater is then sent to a wastewater treatment unit for purification and discharge.

[0021] Pyrolysis gas is purified by electrostatic precipitation to obtain coal gas. Part of the coal gas is sent to the combustion furnace of the coal gas heater for combustion to provide energy, part of it is sent to the heating furnace of the coal gas heater for reheating and then sent back to the dry distillation section of the pyrolysis furnace and the high and low temperature gas mixing device, and part of it is used as coal gas product.

[0022] The beneficial effects of this invention are compared with those of the prior art:

[0023] This invention utilizes the mixed gas from a high-low temperature gas mixing device as a heat carrier to dry low-rank raw coal, removing 99% or more of the moisture from the raw coal. This enables convenient and efficient processing of low-rank raw coal with high moisture content, and the removed moisture is used to cool semi-coke. This not only significantly reduces the production of phenol and ammonia wastewater, but also achieves efficient utilization of water resources and improves energy recycling rate.

[0024] This invention utilizes the mixed gas from a high-low temperature gas mixing device as a heat carrier to dry low-rank raw coal, removing 99% or more of the moisture from the raw coal, reducing the heat required for the pyrolysis of low-rank coal, and improving the energy efficiency of the system.

[0025] The high and low temperature gas mixing device of the present invention uses a baffle plate to initially mix high temperature gas and low temperature gas. At the same time, affected by the gas temperature difference and high speed flow, a vortex will be formed inside the tank during the mixing process. The vortex will drive the swirl plate to rotate, causing the guide structure to rotate synchronously, further enhancing the degree of mixing of the two gases and avoiding uneven heating of low-rank raw coal due to uneven gas mixing.

[0026] This invention utilizes a moisture detector to monitor changes in the moisture content of low-rank raw coal. Then, by adjusting the opening degrees of the high-temperature and low-temperature regulating valves, the proportion of high- and low-temperature gases entering the high- and low-temperature gas mixing device is controlled. This satisfies the dehydration and heating requirements of low-rank raw coal with different moisture contents, improving versatility and making production regulation more flexible, efficient, and intelligent. This increases production efficiency, reduces production costs, avoids the loss of tar and pyrolysis gas due to uncontrollable gas temperature, and improves economic benefits. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the environmentally friendly low-rank coal pyrolysis process of the present invention;

[0028] Figure 2 This is a structural diagram of the high and low temperature gas mixing device of the present invention;

[0029] Figure 3 This is a structural diagram of the spoiler;

[0030] Figure 4 This is a structural diagram of the flow guiding structure;

[0031] Figure 5 This is a structural diagram of the swirl plate;

[0032] Figure 6 This is a structural diagram of a circular slide rail.

[0033] In the diagram: 1. Coal bunker; 2. Drying section of pyrolysis furnace; 3. Dry distillation section of pyrolysis furnace; 4. Cooling section of pyrolysis furnace; 5. Scraper conveyor; 6. Gas purification and oil recovery unit; 7. Wastewater treatment unit; 8. Air blower; 9. Gas heater; 10. Cyclone dust collector; 11. Gas induced draft fan; 12. High and low temperature gas mixing device; 12.1 Low temperature gas inlet pipe; 12.2 High temperature gas inlet pipe; 12.3 Baffle plate; 12.4 Tank body; 12.5 Swirl plate; 12.6 Flow guiding structure; 12.7 Gas outlet; 12.8 Circular slide rail; 12.9 Manhole; 12.10 Low temperature regulating valve; 12.11 High temperature regulating valve; 13. Spray tower; 14. Flue gas purification unit. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0035] like Figure 1-6 As shown, this invention discloses an environmentally friendly low-rank coal pyrolysis device, which includes: a coal bunker 1, a pyrolysis furnace drying section 2, a pyrolysis furnace dry distillation section 3, and a pyrolysis furnace cooling section 4. A moisture detector is installed at the inlet of the coal bunker 1 to monitor changes in the moisture content of the raw coal. The left side of the high- and low-temperature gas mixing device 12 is connected to the pyrolysis furnace drying section 2 via a pipeline, and the right side of the spray tower 13 is connected to the pyrolysis furnace drying section 2 via a pipeline. The left side of the spray tower 13 is connected to the pyrolysis furnace cooling section 4 via a three-way connector and a gas purification and oil recovery unit 6.

[0036] In a specific embodiment, low-rank raw coal enters the coal bunker 1 from the top, and then enters the drying section 2 of the pyrolysis furnace under the action of gravity. The low-rank raw coal is heated and dried by gas at 280℃-390℃ from the high and low temperature gas mixing device 12. After drying in the drying section 2, the low-rank raw coal is heated to 120℃-170℃, and the moisture in the low-rank raw coal is removed. The removed moisture is discharged from the top of the drying section 2 of the pyrolysis furnace along with the gas and enters the spray tower 13. After the gas enters the spray tower 13, it is cooled by spraying, and the removed moisture condenses and precipitates from the gas to form condensate. The condensate is then sent from the bottom of the spray tower 13 to the cooling section 4 of the pyrolysis furnace through a pipe. Most of the cooled gas enters the cooling section 4 of the pyrolysis furnace through a pipe for coke quenching and cooling in the cooling section 4 of the pyrolysis furnace, and a small portion of the cooled gas enters the gas purification and oil recovery unit 6.

[0037] Preferably, the gas at 280℃-390℃ in the high and low temperature gas mixing device 12 can be flue gas or coal gas, but is not limited to flue gas and coal gas.

[0038] The pyrolysis furnace dry distillation section 3 is connected to the gas purification and oil recovery unit 6. The right side of the gas purification and oil recovery unit 6 is connected to the sewage treatment unit 7. At the same time, the gas purification and oil recovery unit 6 outputs tar and gas through pipelines. The gas output pipeline is connected to the combustion furnace and heating furnace of the gas heater 9 through a three-way connector. The right side of the pyrolysis furnace dry distillation section 3 is also connected to the heating furnace of the gas heater 9 through pipelines. The combustion furnace of the gas heater 9 is connected to the blower 8. At the same time, the heating furnace of the gas heater 9 is connected to the high and low temperature gas mixing device 12 through pipelines.

[0039] The left side of the gas heater 9 is connected to the flue gas purification unit 14 via a pipe. The flue gas purification unit 14 is used to treat the flue gas generated by the gas heater 9 during combustion heating, so that the flue gas meets the emission standards after treatment.

[0040] In a specific embodiment, the dehydrated low-rank raw coal enters the pyrolysis section 3 of the pyrolysis furnace from the drying section 2. The gas heater 9 introduces high-temperature gas at 650℃-900℃ into the pyrolysis section 3. The low-rank raw coal entering the pyrolysis section 3 directly contacts and exchanges heat with the high-temperature gas at 650℃-900℃ from the gas heater 9. The low-rank raw coal is heated to 450℃-600℃ and undergoes a pyrolysis reaction, transforming into semi-coke, tar, pyrolysis gas and pyrolysis water.

[0041] Tar, pyrolysis gas, and pyrolysis water are gaseous products. All gaseous products enter the gas purification and oil recovery unit 6 along with the high-temperature gas introduced into the gas heater 9. In the gas purification and oil recovery unit 6, after washing and cooling, most of the tar and pyrolysis water condense and precipitate to form an oil-water mixture. After settling and stratification, the oil-water mixture yields finished tar and generates phenolic ammonia wastewater. This phenolic ammonia wastewater is sent to the wastewater treatment unit 7 and treated to meet discharge standards. The remaining pyrolysis gas is further purified by electrostatic precipitation to obtain coal gas. The purified coal gas is divided into three parts: one part coal... The gas is sent to the combustion furnace of the gas heater 9 for combustion power. Air is supplied by the blower 8, and the gas in the combustion furnace is burned with the help of air to power the gas heater 9. Part of the gas is sold as a product. Part of the gas is sent to the heating furnace of the gas heater 9, and after heating, it forms a gas heat carrier at 650℃-900℃. The gas heat carrier is divided into two parts. One part of the gas heat carrier is sent back to the dry distillation section 3 of the pyrolysis furnace to supply high-temperature gas at 650℃-900℃. The other part of the gas heat carrier is sent to the high and low temperature gas mixing device 12.

[0042] Meanwhile, the solid semi-coke produced by heating low-rank raw coal enters the pyrolysis furnace cooling section 4 through the dry distillation section 3 of the pyrolysis furnace. It is cooled to below 100°C by cold gas from the spray tower 13. At the same time, the condensate precipitated from the spray tower 13 sprays the solid semi-coke. The temperature of the semi-coke drops to below 50°C to form semi-coke product, which is output from the bottom of the pyrolysis furnace cooling section 4.

[0043] The right side of the pyrolysis furnace cooling section 4 is connected in sequence to the cyclone dust collector 10, the gas induced draft fan 11, the high and low temperature mixing device 12, and the pyrolysis furnace drying section 2 via pipes.

[0044] In a specific embodiment, cold gas from the spray tower 13 enters the cooling section 4 of the pyrolysis furnace. The cold gas directly contacts and exchanges heat with the high-temperature semi-coke. After heat exchange, the cold gas is heated to 200℃-350℃. The 200℃-350℃ gas enters the cyclone dust collector 10 from the cooling section 4 of the pyrolysis furnace for dust removal. After dust removal, the 200℃-350℃ gas is sent by the gas induced draft fan 11 to the high and low temperature gas mixing device 12 and is fully mixed with the 650℃-900℃ gas input by the gas heater 9 in the high and low temperature gas mixing device 12. After uniform mixing, a 280℃-390℃ gas is formed. Then the 280℃-390℃ gas returns to the drying section 2 of the pyrolysis furnace and is reused for heating and drying of low-rank raw coal.

[0045] This invention sets up a pyrolysis furnace in three parts and connects it with a spray tower 13, a high and low temperature gas mixing device 12 and a coal gas purification and oil recovery unit 6. This enables the device to process low-rank coal with a moisture content higher than 20%, making it more adaptable to raw materials, improving energy utilization, and achieving a significant reduction in phenol and ammonia wastewater. This reduces investment costs, promotes green energy saving, and improves the environmental and economic benefits of the system.

[0046] The high and low temperature gas mixing device 12 includes a tank body 12.4, a low temperature gas inlet pipe 12.1, a high temperature gas inlet pipe 12.2, a baffle plate 12.3, a swirl plate 12.5, a flow guiding structure 12.6, and an outlet pipe 12.7. The low temperature gas inlet pipe 12.1 is installed at the top of the tank body 12.4 and is connected to the gas induced draft fan 11. A low temperature regulating valve 12.10 is installed at the end of the low temperature gas inlet pipe 12.2. Two high temperature gas inlet pipes 12.2 are symmetrically arranged on the left and right outer circumferences of the upper part of the tank body 12.4. The high temperature gas inlet pipes 12.2 are obliquely inserted into the tank body 12.4 and are connected to the gas heater 9. A high temperature regulating valve 12.11 is installed at the end of the high temperature gas inlet pipe 12.7 is installed at the bottom of the tank body 12.4 and is connected to the drying section 2 of the pyrolysis furnace.

[0047] The moisture detector and the low-temperature regulating valve 12.10 and high-temperature regulating valve 12.11 are all electrically connected. The moisture detector detects the moisture content of the low-rank raw coal fed into the coal bunker 1. Based on the moisture content data from the moisture detector, the opening degree of the low-temperature regulating valve 12.10 and the high-temperature regulating valve 12.11 are adjusted to control the ratio of high-temperature gas and low-temperature gas entering the high-low temperature gas mixing device 12, so as to meet the dewatering and heating requirements of low-rank raw coal with different moisture contents and improve versatility.

[0048] Preferably, the tilt angle of the high-temperature gas inlet pipe 12.2 can be adjusted according to different working conditions, and the number of high-temperature gas inlet pipes 12.2 can be set according to actual conditions.

[0049] like Figure 4As shown, multiple baffles 12.3 are independently and interlaced on the inner wall of the tank 12.4. The baffles 12.3 have round holes. By changing the direction of the gas through the baffles 12.3, the mixing degree of high and low temperature gases is enhanced.

[0050] like Figure 5 and Figure 6 As shown, a circular slide rail 12.8 is provided on the lower inner wall of the tank body 12.4. The flow guiding structure 12.6 is rotatably installed on the circular slide rail 12.8. The flow guiding structure 12.6 is a spherical cover structure. Multiple air vents are arranged circumferentially from the inside to the outside on the flow guiding structure 12.6. Multiple swirl plates 12.5 are evenly arranged circumferentially on the upper outer wall of the flow guiding structure 12.6 to increase the contact area with the gas. The swirl plates 12.5 are inclinedly arranged on the flow guiding structure 12.6.

[0051] When high-temperature gas and low-temperature gas are mixed at high speed, eddies will be generated, which will drive the swirl plate 12.5 to rotate. The swirl plate 12.5 will drive the guide structure 12.6 to rotate synchronously along the circular slide rail 12.8, further enhancing the degree of gas mixing.

[0052] A manhole 12.9 is provided on the left side of the tank 12.4, through which staff can inspect and maintain the high and low temperature gas mixing device 12.

[0053] In a specific embodiment, the low-temperature gas in the gas induced draft fan 11 is injected into the tank 12.4 at high speed through the low-temperature gas inlet pipe 12.1, while the high-temperature gas in the gas heater 9 is injected into the tank 12.4 at high speed through the high-temperature gas inlet pipe 12.2. The high-temperature gas and the low-temperature gas will diffuse in all directions upon entering the tank 12.4. The two gases will be initially mixed by the baffle plate 12.3. At the same time, affected by the gas temperature difference and high-speed flow, a vortex will be formed inside the tank 12.4 during the mixing process. The vortex will drive the swirl plate 12.5 to rotate, and the guide structure 12.6 will rotate synchronously along the circular slide rail 12.8, further enhancing the mixing degree of the two gases. The fully mixed gas is discharged from the gas outlet 7 and introduced into the drying section 2 of the pyrolysis furnace.

[0054] This invention also discloses an environmentally friendly low-rank coal pyrolysis process, comprising the following steps:

[0055] Step 1: Low-rank raw coal is fed into the drying section 2 of the pyrolysis furnace through coal bunker 1 for dehydration and heating;

[0056] Step 2: The dehydrated low-rank raw coal enters the dry distillation section 3 of the pyrolysis furnace for high-temperature heat exchange, and is converted into semi-coke, tar, pyrolysis gas and pyrolysis water;

[0057] Step 3: The gaseous products, tar, pyrolysis gas and pyrolysis water, enter the gas purification and oil recovery unit 6 for purification and transmission.

[0058] Step 3.1: The tar and pyrolysis water are condensed to precipitate an oil-water mixture. After standing and separating, tar and phenol-ammonia wastewater are obtained. The phenol-ammonia wastewater is sent to wastewater treatment unit 7 for purification and discharge.

[0059] Step 3.2: The remaining pyrolysis gas is purified by electrostatic precipitation to obtain coal gas. Part of the coal gas is sent to the combustion furnace of the coal gas heater 9 for combustion and energy supply, part of the coal gas is sent to the heating furnace of the coal gas heater 9 for reheating and then sent back to the dry distillation section 3 of the pyrolysis furnace and the high and low temperature gas mixing device 12, and part of the coal gas is used as coal gas product.

[0060] Step 4: The semi-coke in solid form enters the cooling section 4 of the pyrolysis furnace, where it is cooled by cold gas and condensate from the spray tower 13 to form the semi-coke product. The semi-coke product is output from the bottom of the cooling section 4 of the pyrolysis furnace.

[0061] The beneficial effects of this invention are compared with those of the prior art:

[0062] This invention utilizes the mixed gas from a high-low temperature gas mixing device as a heat carrier to dry low-rank raw coal, removing 99% or more of the moisture from the raw coal. This enables convenient and efficient processing of low-rank raw coal with high moisture content, and the removed moisture is used to cool semi-coke. This not only significantly reduces the production of phenol and ammonia wastewater, but also achieves efficient utilization of water resources and improves energy recycling rate.

[0063] This invention utilizes the mixed gas from a high-low temperature gas mixing device as a heat carrier to dry low-rank raw coal, removing 99% or more of the moisture from the raw coal, reducing the heat required for the pyrolysis of low-rank coal, and improving the energy efficiency of the system.

[0064] The high and low temperature gas mixing device of the present invention uses a baffle plate to initially mix high temperature gas and low temperature gas. At the same time, affected by the gas temperature difference and high speed flow, a vortex will be formed inside the tank during the mixing process. The vortex will drive the swirl plate to rotate, causing the guide structure to rotate synchronously, further enhancing the degree of mixing of the two gases and avoiding uneven heating of low-rank raw coal due to uneven gas mixing.

[0065] This invention utilizes a moisture detector to monitor changes in the moisture content of low-rank raw coal. Then, by adjusting the opening degrees of the high-temperature and low-temperature regulating valves, the proportion of high- and low-temperature gases entering the high- and low-temperature gas mixing device is controlled. This satisfies the dehydration and heating requirements of low-rank raw coal with different moisture contents, improving versatility and making production regulation more flexible, efficient, and intelligent. This increases production efficiency, reduces production costs, avoids the loss of tar and pyrolysis gas due to uncontrollable gas temperature, and improves economic benefits.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. An environmentally friendly low-rank coal pyrolysis device, comprising: The pyrolysis furnace and high / low temperature gas mixing device (12) are characterized in that: The high and low temperature gas mixing device (12) includes: a tank (12.4), a low temperature gas inlet pipe (12.1), a high temperature gas inlet pipe (12.2), and an outlet pipe (12.7). The low temperature gas enters the tank (12.4) through the low temperature gas inlet pipe (12.1). A low temperature regulating valve (12.10) is provided at the end of the low temperature gas inlet pipe (12.1). The high temperature gas enters the tank (12.4) through a plurality of symmetrically arranged high temperature gas inlet pipes (12.2). 2) A high-temperature regulating valve (12.11) is installed at the end, and a gas outlet (12.7) is installed at the bottom of the tank (12.4). The gas outlet (12.7) is connected to the upper part of the pyrolysis furnace. A moisture detector is installed on the pyrolysis furnace to detect the moisture content of the low-rank raw coal. The moisture detector and the low-temperature regulating valve (12.10) are electrically connected to the high-temperature regulating valve (12.11). The opening degree of the two regulating valves is adjusted by the moisture content data of the moisture detector to adjust the mixing ratio of high and low temperature gases, so as to meet the process requirements of low-rank raw coal with different moisture contents.

2. The environmentally friendly low-rank coal pyrolysis device according to claim 1, characterized in that: The inner wall of the lower side of the tank (12.4) is provided with a circular slide rail (12.8). The flow guiding structure (12.6) is rotatably installed on the circular slide rail (12.8). The flow guiding structure (12.6) is circumferentially arranged with multiple vent holes. The outer wall of the upper side of the flow guiding structure (12.6) is uniformly arranged with multiple swirl plates (12.5). When the high and low temperature gases are mixed, the vortex generated drives the flow guiding structure (12.6) to rotate along the circular slide rail (12.8) through the swirl plates (12.5).

3. The environmentally friendly low-rank coal pyrolysis device according to claim 1 or 2, characterized in that: Multiple baffles (12.3) are staggered on the inner wall of the tank (12.4). The baffles (12.3) have round holes. The baffles (12.3) change the direction of the gas and enhance the mixing degree of high and low temperature gases. A manhole (12.9) is provided on one side of the tank (12.4) for inspection and maintenance.

4. The environmentally friendly low-rank coal pyrolysis device according to claim 1, characterized in that: The pyrolysis furnace is provided with a coal bunker (1), a pyrolysis furnace drying section (2), a pyrolysis furnace dry distillation section (3), and a pyrolysis furnace cooling section (4) from top to bottom. A moisture detector is installed on the coal bunker (1). The outlet (12.7) of the high and low temperature gas mixing device (12) is connected to the pyrolysis furnace drying section (2). One side of the spray tower (13) is connected to the pyrolysis furnace drying section (2). One side of the spray tower (13) is connected to the gas purification and oil recovery unit (6) and the pyrolysis furnace cooling section (4) through a three-way connector.

5. The environmentally friendly low-rank coal pyrolysis device according to claim 4, characterized in that: The cooling section (4) of the pyrolysis furnace is connected to the low-temperature gas inlet pipe (12.1) on the high and low temperature mixing device (12) via a cyclone dust collector (10) and a gas induced draft fan (11) in sequence through a pipeline.

6. The environmentally friendly low-rank coal pyrolysis device according to claim 4, characterized in that: The pyrolysis furnace dry distillation section (3) is connected to the gas purification and oil recovery unit (6), and one side of the gas purification and oil recovery unit (6) is connected to the sewage treatment unit (7).

7. The environmentally friendly low-rank coal pyrolysis device according to claim 6, characterized in that: The gas purification and oil recovery unit (6) outputs tar and gas through a pipeline. The gas output pipeline is connected to the combustion furnace and heating furnace of the gas heater (9) through a three-way connector. The dry distillation section (3) of the pyrolysis furnace is connected to the heating furnace of the gas heater (9) through a pipeline. The heating furnace of the gas heater (9) is also connected to the high temperature gas inlet pipe (12.2) on the high and low temperature gas mixing device (12).

8. The environmentally friendly low-rank coal pyrolysis device according to claim 7, characterized in that: The gas heater (9) is connected to a flue gas purification unit (14) via a pipe on one side. The flue gas purification unit (14) is used to purify the flue gas of the gas heater (9) during combustion. At the same time, the combustion furnace and blower (8) of the gas heater (9) are connected to assist the combustion of the gas heater (9).

9. An environmentally friendly low-rank coal pyrolysis process, based on an environmentally friendly low-rank coal pyrolysis device according to any one of claims 1-8, characterized in that: Low-rank raw coal is fed into the drying section (2) of the pyrolysis furnace through the coal bunker (1) for heating and dehydration; After dehydration, the low-rank raw coal enters the dry distillation section (3) of the pyrolysis furnace for high-temperature heat exchange and is converted into semi-coke, tar, pyrolysis gas and pyrolysis water; The gaseous products, tar, pyrolysis gas and pyrolysis water, enter the gas purification and oil recovery unit (6) for purification and output; The semi-coke, a solid product, enters the cooling section (4) of the pyrolysis furnace and is cooled by cold gas and condensate from the spray tower (13) to form a semi-coke product. The semi-coke product is output from the bottom of the cooling section (4) of the pyrolysis furnace.

10. The environmentally friendly low-rank coal pyrolysis process according to claim 9, characterized in that: Tar and pyrolysis water are condensed to precipitate an oil-water mixture. After standing and separating into layers, tar and phenol-ammonia wastewater are obtained. The phenol-ammonia wastewater is sent to the wastewater treatment unit (7) for purification and discharge. Pyrolysis gas is purified by electrostatic precipitation to obtain coal gas. Part of the coal gas is sent to the combustion furnace of the coal gas heater (9) for combustion to provide energy, part of the coal gas is sent to the heating furnace of the coal gas heater (9) for reheating and then sent back to the dry distillation section (3) of the pyrolysis furnace and the high and low temperature gas mixing device (12), and part of the coal gas is used as a coal gas product.

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