Novel lignite drying system and process based on low-temperature drying

Abstract

The invention discloses a novel lignite drying system based on low-temperature drying, which comprises a feeding unit used for uniformly mixing lignite raw materials and then feeding the lignite raw materials into a crushing unit; the crushing unit is used for crushing lignite into granular coal and then feeding the granular coal into the pre-homogenizing unit; the pre-homogenization unit is used for carrying out homogenization stacking and homogenization taking on the crushed lignite and feeding the particle coal subjected to homogenization taking into the drying unit; the drying unit is used for drying the homogenized granular coal and feeding the dried lignite into the finished product storing and delivering unit; the finished product storing and delivering unit is used for storing and delivering the dried lignite in a grading manner; and the waste gas treatment unit is used for carrying out dust removal treatment on waste flue gas generated during drying of the drying unit. The device has the advantages of comprehensive functions, easy operation, safe and stable operation, environmental protection, high efficiency and the like, and solves the problems of low lignite single-machine drying yield, high energy consumption, unstable quality, high pollution, poor safety and environmental protection performance and the like in the existing lignite evaporation drying dehydration technology.

Description

Technical Field

[0001] The present invention belongs to the field of lignite drying, and in particular relates to a new lignite drying system and process based on low-temperature drying. Background Art

[0002] With the implementation of the sustainable development strategy, the rational development and comprehensive utilization of coal and other mineral resources have become an important issue. The full development and utilization of low-quality wet lignite, which was originally idle and piled up as waste, is urgent. Compared with other types of coal, lignite has high moisture content, high volatile matter, high organic content, large changes in ash content and melting point, low density, easy spontaneous combustion, and easy explosion of coal powder. In addition, the spontaneous combustion tendency of lignite is not suitable for long-distance transportation, and the high volatile matter also brings problems of spontaneous combustion and coal powder explosion.

[0003] At present, the main drying processes for lignite in the world include mechanical dehydration process, evaporative drying dehydration process, and non-evaporative drying dehydration process. These process methods have their own advantages and disadvantages. Among them, the traditional hot air drum drying-direct heating process has a small processing scale and poor safety and environmental protection; while the solar drying process requires a large area of ​​land, and production is also closely related to seasonal and climatic conditions. Since this technology is suitable for lignite mining areas with relatively cheap labor and drought, it is difficult to promote. Other drying processes also have problems such as small single-machine processing capacity, low heat transfer efficiency, easy ignition, severe wear, and overly complex system structure. In particular, steam drying has a large amount of wastewater treatment and high environmental risks. Summary of the invention

[0004] Based on the above-mentioned problems of the prior art, the present invention provides a new type of lignite drying system and process based on low-temperature drying, which has the advantages of comprehensive functions, easy operation, safe and stable operation, environmental protection and high efficiency, etc., and solves the problems of low output of lignite single machine drying, high energy consumption, unstable quality, high pollution, poor safety and environmental protection performance in the current lignite evaporation drying and dehydration technology.

[0005] The main technical solutions adopted in the present invention are:

[0006] A novel drying system for lignite based on low temperature drying, comprising:

[0007] A feeding unit, including a lignite feeder, is used to mix the large pieces of lignite raw materials evenly and then feed them into the crushing unit;

[0008] A crushing unit, including a lignite crusher, is used to crush the large chunks of lignite raw material into granular coal and then feed it into a pre-homogenizing unit;

[0009] The pre-homogenization unit is used to homogenize the crushed lignite and to carry out homogenization and feeding, and to send the granular coal after homogenization and feeding to the drying unit;

[0010] The drying unit is used to perform low-temperature aerobic drying on the homogenized coal particles and send the dried lignite to the finished product storage and shipping unit;

[0011] Finished product storage and shipping unit, used for graded storage and shipping of dried lignite;

[0012] The waste gas treatment unit is used to remove dust from the waste gas generated by the drying unit during drying.

[0013] Preferably, the pre-homogenization unit comprises a lignite stacker and a lignite reclaimer, wherein the lignite stacker homogenizes the granular coal fed by the crushing unit to form a stockpile, and the lignite reclaimer is used to homogenize and reclaim the stockpile formed by the homogenized stockpile.

[0014] Preferably, the drying unit comprises a hot air stove unit, a drying coal feeding unit and a drying machine unit, wherein:

[0015] The hot blast furnace unit comprises a hot blast furnace, a hot flue gas distributor, a cold air blower, a plurality of cold air valves and a plurality of hot flue gas blowers, wherein the high-temperature hot flue gas generated by the hot blast furnace and the cold air introduced by the cold air blower enter the hot flue gas distributor for temperature adjustment and oxygen control, and then are sent into the drying unit by the hot flue gas blower through the cold air valve;

[0016] The drying coal feeding unit includes a coal feeding bin, a coal powder quantitative feeder and an air-locking uniform distributor, wherein the granular coal in the coal feeding bin is fed into the air-locking uniform distributor through the coal powder quantitative feeder below the coal feeding bin, and the air-locking uniform distributor feeds the granular coal into the drying unit for drying;

[0017] The dryer unit includes a fluidized grate dryer, which includes a hydraulic system and an air-locking screw conveyor, wherein the air inlet of the lower hot air chamber of the fluidized grate dryer is connected to the air outlet of the hot air furnace unit, the air outlet of the upper exhaust gas chamber of the fluidized grate dryer is connected to the exhaust gas treatment unit, the grate plate of the fluidized grate dryer is drivingly connected to the hydraulic system, and the discharge end of the fluidized grate dryer adopts an air-locking screw conveyor to deliver the dried granular coal into the finished product storage and shipping unit.

[0018] Preferably, the air outlet of the hot air furnace unit is connected to the air inlet of the dryer unit via a pipeline, and an exhaust gas heating controller is installed on the pipeline to heat the exhaust gas discharged from the dryer unit.

[0019] Preferably, the finished product storage and shipping unit includes a finished product storage warehouse, a finished lump coal shipping warehouse, a finished coal powder shipping warehouse and an intermediate coal warehouse. The granular coal dried by the drying unit is sent to the finished product storage warehouse for storage, and the granular coal in the finished product storage warehouse is sent to the finished lump coal shipping warehouse for shipping. The intermediate coal warehouse collects and stores the coal powder recovered from the exhaust gas treatment unit, and the coal powder in the intermediate coal warehouse is pneumatically conveyed into the finished coal powder shipping warehouse for shipping.

[0020] Preferably, the waste gas treatment unit includes a pulse bag dust collection system, a waste gas exhaust fan, and an intermediate conveying equipment. The waste flue gas from the drying unit is discharged after passing through the pulse bag dust collection system and the waste gas exhaust fan in sequence. The coal powder collected by the pulse bag dust collection system is transported into the finished product storage and shipping unit by the intermediate conveying equipment.

[0021] Preferably, the exhaust gas treatment unit further comprises a circulating exhaust gas control valve, and the exhaust gas discharged from the exhaust gas chimney is connected to the hot flue gas distributor in the hot blast furnace unit through the circulating exhaust gas control valve, so as to adjust the temperature and control the oxygen of the high-temperature hot flue gas.

[0022] Preferably, it also includes a fire-fighting unit, which includes a dry powder fire-fighting system, an inert gas fire-fighting system and several explosion-proof pressure relief valves, wherein:

[0023] A dry powder fire extinguishing system is provided in the drying unit;

[0024] The waste gas treatment unit, drying unit, intermediate pulverized coal bin, and finished pulverized coal shipping bin are provided with an inert gas fire fighting system;

[0025] A plurality of explosion-proof pressure relief valves are arranged on the pulse bag dust collecting system in the waste gas treatment unit and in the air duct connected to the drying unit.

[0026] Preferably, the feeding unit is further provided with a dust collector I, which collects the coal dust generated during the conveying and feeding process of the lignite feeder and sends it to the pre-homogenization unit. The crushing unit is further provided with a dust collector II, wherein the dust collector II collects the coal dust generated during the crushing process of the lignite crusher and sends it to the pre-homogenization unit. The coal feeding bin of the drying unit is further provided with a dust collector III, which collects the coal dust generated during the conveying process and sends it into the dryer together with the raw materials.

[0027] A novel drying process for lignite based on low temperature drying comprises the following steps:

[0028] S1: The raw coal in the raw coal pile in the feeding unit is homogenized for the first time according to the quality, and the raw coal after the first homogenization is sent to the crushing unit to be crushed into granular coal;

[0029] S2: The crushed coal particles and the coal dust generated in the process are transported together into the pre-homogenization pile shed in the pre-homogenization unit, and a second homogenization is performed to form a homogenized stockpile;

[0030] S3: The homogenized material pile is homogenized for the third time by homogenizing and feeding, and is sent to a drying unit for low-temperature aerobic drying using hot flue gas;

[0031] S4: The dried granular coal is sent to the finished product storage and shipping unit for storage and shipping as lump coal;

[0032] S5: The waste gas generated by the drying process is dust-removed by the waste gas treatment unit. The treated waste gas is circulated into the atmosphere for discharge or circulated into the hot air furnace unit to adjust the temperature and control the oxygen of the high-temperature flue gas. At the same time, the pulverized coal collected by the waste gas treatment unit is sent to the finished product storage and shipment unit for storage and shipment as pulverized coal.

[0033] Beneficial effects: The present invention provides a new type of lignite drying system and process based on low temperature drying, which has the following advantages:

[0034] (1) The present invention recycles the waste gas generated during the drying process and fully mixes it with the high-temperature hot flue gas to achieve temperature control and oxygen control, which not only achieves efficient utilization of thermal energy, thereby optimizing energy consumption, but also effectively reduces the emission of waste gas, reduces the impact on the environment, and promotes energy conservation and environmental protection in the production process.

[0035] (2) The present invention realizes low-temperature drying of lignite by adjusting the temperature and controlling the oxygen of high-temperature hot flue gas. During the low-temperature drying process, the chemical composition and physical properties of the lignite are less affected, which makes it easier to maintain the original quality of the lignite and improve its economic value. In addition, the energy consumption of low-temperature drying is relatively low, and the safety is relatively high, and it is not easy to cause safety hazards such as spontaneous combustion or explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the system structure of this embodiment 1;

[0037] Figure 2 is the process flow chart of this embodiment 1;

[0038] In the figure: feeding unit 1, lignite feeder 1-1, dust collector Ⅰ1-2, crushing unit 2, lignite crusher 2-1, dust collector Ⅱ2-2, pre-homogenizing unit 3, lignite stacker 3-1, lignite reclaimer 3-2, drying unit 4, hot air furnace unit 4-1, hot air furnace 4-11, hot flue gas distributor 4-12, cold air fan 4-13, cold air valve 4-14, hot flue gas fan 4-15, exhaust gas heating controller 4-16, drying coal feeding unit 4-2, coal feeding bin 4-21, coal powder quantitative feeder 4-22, air lock uniform distribution Feeder 4-23, dust collector III 4-24, dryer unit 4-3, fluidized grate dryer 4-31, hydraulic system 4-32, air-locking screw conveyor 4-33, finished product storage and shipping unit 5, finished product storage 5-1, finished lump coal shipping bin 5-2, finished coal powder shipping bin 5-3, intermediate coal bin 5-4, waste gas treatment unit 6, pulse bag dust collection system 6-1, waste gas exhaust fan 6-2, waste gas chimney 6-3, circulating waste gas control valve 6-4, fire fighting unit 7, dry powder fire extinguishing system 7-1, inert gas fire fighting system 7-2. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0040] Example 1

[0041] A brown coal homogenization drying system, such as Figure 1 As shown, including:

[0042] The feeding unit 1 comprises a lignite feeder 1-1 and a dust collector Ⅰ1-2, wherein the lignite feeder 1-1 is used to mix the large lignite raw materials uniformly and then feed them into the crushing unit, and the dust collector Ⅰ1-2 collects the coal dust generated in the feeding process of the lignite feeder 1-1 and feeds it into the pre-homogenization unit 3. In this embodiment 1, the lignite feeder 1-1 is preferably a plate feeder, and the lignite raw materials are fed into the plate feeder using a grid.

[0043] The crushing unit 2 includes a lignite crusher 2-1 and a dust collector II 2-2, wherein the lignite crusher 2-1 is used to crush the lignite bulk raw material into coal particles that meet the conditions (certain particle size conditions) and then send them to the pre-homogenization unit 3, and the dust collector II 2-2 collects the coal dust generated during the crushing process of the lignite crusher and sends it to the pre-homogenization unit 3. In this embodiment 1, the lignite crusher 2-1 is preferably a tooth crusher, which can crush the lignite raw material into coal particles below 50 mm.

[0044] The pre-homogenization unit 3 includes a lignite stocker 3-1 and a lignite reclaimer 3-2, wherein the lignite stocker 3-1 homogenizes the granular coal fed into the crushing unit 2 to form a stockpile (i.e., homogenized stockpile), and the lignite reclaimer 3-2 homogenizes and reclaims the stockpile formed by the lignite stocker 3-1, and sends the granular coal that meets the conditions (certain particle size conditions) after homogenization and reclaiming to the drying unit 4. In this embodiment 1, the lignite stocker 3-1 is a cantilever stocker located in the pre-homogenization stockpile, and the lignite reclaimer 3-2 is a bridge reclaimer used to homogenize and reclaim the coal in the pre-homogenization stockpile. In order to further achieve stable and safe production, a small amount of coal dust generated during the homogenization stockpile process can be sprayed with water mist to reduce dust.

[0045] The drying unit 4 is used to dry the homogenized coal particles and send the dried lignite to the finished product storage and delivery unit 5. In this embodiment 1, the drying unit 4 includes a hot air furnace unit 4-1, a drying coal feeding unit 4-2 and a drying machine unit 4-3.

[0046] In this embodiment 1, the hot air furnace unit 4-1 includes a hot air furnace 4-11, a hot flue gas distributor 4-12, a cold air blower 4-13, a plurality of cold air valves 4-14 and a plurality of hot flue gas blowers 4-15. Specifically, the high-temperature hot flue gas required by the drying unit 4 is generated by the combustion of fuel in the hot air furnace. The fuel in the fuel shed is sent to the fuel bin of the hot air furnace 4-11 by a conveying device such as a forklift, and then fed into the hot air furnace 4-11 by a fuel quantitative feeder under the fuel bin for combustion, generating a high-temperature hot flue gas of about 800°C for drying. The high-temperature hot flue gas generated by the hot air furnace 4-11 and the cold air introduced by the cold air blower 4-13 enter the hot flue gas distributor 4-12 for temperature adjustment and oxygen control. Then, it is sent to the dryer unit 4-3 through the cold air valve 4-14 and the hot flue gas blower 4-15. In the present invention, the high-temperature hot flue gas is generally adjusted to a safe temperature of ≤200°C, and the oxygen content is reduced to a certain level, and a low-temperature aerobic drying technology is used to improve production safety.

[0047] In order to further achieve energy saving and consumption reduction, and environmentally friendly production, in this embodiment 1, a circulating exhaust gas control valve 4-4 is also set, and the exhaust gas discharged from the exhaust chimney 6-3 is connected to the hot flue gas distributor 4-12 in the hot blast furnace unit 4-1 through the circulating exhaust gas control valve 4-4, which is used to adjust the temperature and oxygen of the high-temperature hot flue gas to achieve low-temperature drying. This process realizes the recycling of waste flue gas, can recover waste heat, adjust temperature and control oxygen, and save energy and reduce consumption.

[0048] In this embodiment 1, based on environmental protection production requirements, the hot blast furnaces 4-11 are preferably biomass fuel hot blast furnaces, and any existing hot blast furnaces that can achieve high-temperature flue gas production are applicable.

[0049] In the present invention, the number of hot flue gas fans 4-15 and cold air valves 4-14 corresponds one to one, and their specific number can be selectively designed according to actual needs. In this embodiment 1, 8 are preferred.

[0050] The drying coal feeding unit 4-2 includes a coal feeding bin 4-21, a coal powder quantitative feeder 4-22 and an air-locking uniform distributor 4-23, wherein the granular coal in the coal feeding bin 4-21 is fed into the air-locking uniform distributor 4-23 through the coal powder quantitative feeder 4-22 below the coal feeding bin 4-21, and the air-locking uniform distributor 4-23 feeds the granular coal into the drying machine unit 4-3 for drying. In this embodiment 1, a dust collector III 4-24 is also provided in the coal feeding bin 4-21, and the dust collector III 4-24 collects the coal dust generated during the transportation process and feeds it into the drying machine unit 4-3 together with the raw materials.

[0051] The dryer unit 4-3 includes a fluidized grate dryer 4-31, which includes a hydraulic system 4-32 and an air-locking screw conveyor 4-33. The lower chamber of the fluidized grate dryer is a hot air chamber, the upper chamber is an exhaust gas chamber, and the middle is a fluidized grate bed, wherein the air inlet of the lower chamber hot air chamber of the fluidized grate dryer 4-31 is connected to the air outlet of the hot air furnace unit 4-1, and the air outlet of the upper chamber exhaust gas chamber of the fluidized grate dryer 4-31 is connected to the exhaust gas treatment unit 6, the grate plate of the fluidized grate dryer 4-31 is drivingly connected to the hydraulic system 4-32, and the discharge end of the fluidized grate dryer 4-31 uses an air-locking screw conveyor 4-33 to deliver the dried granular coal into the finished product storage and shipping unit 5. After the coal powder in the drying coal feeding unit 4-2 is fed into the grate bed of the fluidized grate dryer 4-31, the grate plate is driven forward by the hydraulic system 4-32. At the same time, by adjusting the movement speed of the grate plate, a stable and efficient drying material layer is formed. At this time, the hot flue gas in the hot air chamber of the fluidized grate dryer 4-31 forms a through-flow through the gaps in the grate plate and directly contacts the coal particles, quickly evaporating the moisture.

[0052] In this embodiment 1, the air-locking screw conveyor 4-33 adopts an air-locking shaftless screw auger, the main purpose of which is to prevent cold air from leaking into the dryer unit and affecting the oxygen content in the dryer.

[0053] In this embodiment 1, the air outlet of the hot air furnace unit 4-1 is connected to the air outlet of the dryer unit 4-2 through a pipe, and an exhaust gas heating controller 4-16 is installed on the pipe to heat the exhaust gas discharged from the dryer unit 4-3. The present invention can use the exhaust heating controller 4-16 to control the hot flue gas generated by the hot air furnace unit 4-1 to heat the exhaust gas discharged from the dryer unit 4-3 according to the needs, thereby increasing the exhaust gas temperature entering the pulse bag dust collection system 6-1, preventing the temperature entering the pulse bag dust collection system 6-1 from being lower than the dew point temperature, and preventing the exhaust gas from condensing to produce corrosion, material accumulation, and bag sticking.

[0054] The finished product storage and shipping unit 5 is used to grade and store and ship the dried lignite. In this embodiment 1, the finished product storage and shipping unit 5 includes a finished product storage warehouse 5-1, a finished lump coal shipping warehouse 5-2, a finished coal powder shipping warehouse 5-3 and an intermediate coal warehouse 5-4. The granular coal dried by the drying unit 4 is sent to the finished product storage warehouse 5-1 for storage by the air-locking screw conveyor 4-33, and the lump coal in the finished product storage warehouse 5-1 is sent to the finished lump coal shipping warehouse 5-2 for shipping. The intermediate coal warehouse 5-4 collects and stores the coal powder recovered from the exhaust gas treatment unit 6. The coal powder in the intermediate coal warehouse 5-4 is pneumatically conveyed into the finished coal powder shipping warehouse 5-3 for shipping.

[0055] The waste gas treatment unit 6 is used to remove dust from the waste gas generated by the drying unit 4 during drying. In this embodiment 1, the waste gas treatment unit 6 includes a pulse bag dust collection system 6-1, a waste gas exhaust fan 6-2 and a waste gas chimney 6-3. The waste gas of the drying unit 4 is discharged from the waste gas chimney 6-3 after passing through the pulse bag dust collection system 6-1 and the waste gas exhaust fan 6-2 in sequence. The dust emission concentration of the waste gas after dust removal is generally ≤20mg / Nm 3 The pulverized coal collected by the pulse bag dust collecting system 6-1 is transported to the intermediate pulverized coal bin 5-4 by an intermediate conveying device. In this embodiment 1, the intermediate conveying device 5-4 is preferably a chain conveyor.

[0056] The waste gas treatment unit 6 also includes a circulating waste gas control valve 6-4, and the waste gas discharged from the waste gas chimney 6-3 is connected to the hot flue gas distributor 4-12 in the hot blast furnace unit 4-1 through the circulating waste gas control valve 6-4, which is used to adjust the temperature and control the oxygen of the high-temperature hot flue gas.

[0057] The fire fighting unit 7 includes a dry powder fire extinguishing system 7-1, an inert gas fire fighting system 7-2 and several explosion-proof pressure relief valves, wherein:

[0058] A dry powder fire extinguishing system is provided in the drying unit 4;

[0059] The waste gas treatment unit 6, drying unit 4, intermediate coal powder bin 5-4, and finished coal powder shipping bin 5-4 are provided with an inert gas fire fighting system 7-2; the inert gas is preferably nitrogen, and the pulse bag dust collection system 6-1 in the waste gas treatment unit uses inert gas (nitrogen) to perform pulse blowing on the pulse bag dust collection system.

[0060] Several explosion-proof pressure relief valves are arranged on the pulse bag dust collection system 6-1 in the waste gas treatment unit 6 and in the air duct connected to the drying unit 4. Among them, 3 are arranged on the air duct and 32 are arranged on the pulse bag dust collection system.

[0061] In addition, in the present invention, fire hydrants and dry powder fire extinguishers are installed in the raw coal pile shed and pre-homogenization pile shed; the pulse bag dust collection system is designed as an independent unit grid dust removal chamber; and fire hydrants, fire water monitors, and dry powder fire extinguishers are installed in the finished coal shed. The above are all conventional technologies, and those skilled in the art can selectively set them according to fire protection needs.

[0062] In this embodiment 1, belt conveyors are used as lignite conveying equipment for conveying lignite between the feeding unit 1 and the crushing unit 2, between the crushing unit 2 and the pre-homogenizing unit 3, between the pre-homogenizing unit 3 and the drying unit 4, and between the drying unit 4 and the finished product storage and shipping unit 5. Those skilled in the art can also select lignite conveying equipment according to actual transportation requirements.

[0063] In the present invention, a DCS control system is used to control the entire production line, which belongs to conventional technology and is therefore not described in detail.

[0064] Based on the lignite homogenizing and drying system described in Example 1, the present invention also proposes a lignite homogenizing and drying process for upgrading lignite and increasing the processing capacity of a single lignite machine to 100-120 t / h (wet coal). Figure 2 As shown, the specific method is as follows:

[0065] S1: The raw coal from different areas in the raw coal pile in the feeding unit 1 is first homogenized according to quality, and the raw coal after the first homogenization is crushed into coal particles; specifically, the wet lignite from the mine or the coal storage yard is first piled in different areas of the raw coal pile according to different qualities, and then the raw coal from different areas is first homogenized according to quality by a forklift, and is fed into the lignite feeder 1-1 through a grid. The raw coal is evenly and stably fed from the lignite feeder 1-1 to the lignite crusher 2-1 of the crushing unit 2 through the lignite conveying equipment, and the raw coal is crushed into coal particles below 50 mm.

[0066] S2: The crushed granular coal and the coal dust generated in the process (crushing and conveying process) are transported together into the pre-homogenization pile shed of the pre-homogenization unit 3 for a second homogenization to form a homogenized stockpile; specifically, the coal crushed by the lignite crusher 2-1 and a small amount of coal dust generated in the process are transported to the lignite stocker 3-1 in the pre-homogenization pile shed through the lignite conveying equipment, and the lignite stocker 3-1 performs a second homogenization to form a homogenized stockpile. The small amount of coal dust generated in the homogenization stockpile process is sprayed with water mist by the spraying equipment to reduce dust;

[0067] S3: The homogenized material pile is homogenized for the third time by homogenizing and taking materials, and then sent to the drying unit 4 for low-temperature drying treatment using hot flue gas; specifically, the material pile in the pre-homogenized pile shed is homogenized and taken by the lignite taker 3-2 to achieve the third homogenization, and then sent to the coal feeding bin 4-21 of the drying coal feeding unit 4-2 through the lignite conveying equipment, and then sent to the air-locking uniform distributor 4-23 by the coal powder quantitative feeder 4-22 under the coal feeding bin 4-21 through the lignite conveying equipment, and then sent to the grate bed of the fluidized grate dryer 4-31 after uniform distribution. A small amount of coal dust generated during the transportation process can be collected by the dust collector III 4-24 and then sent to the fluidized grate dryer together with the raw materials by the coal powder quantitative feeder 4-22 and the air-locking uniform distributor 4-23.

[0068] S4: The dried granular coal is sent to the finished coal storage 5-1 of the finished product storage and shipping unit 5 for storage, and then sent from the finished coal storage 5-1 to the finished lump coal shipping warehouse 5-2 for shipping;

[0069] S5: The waste flue gas generated by the drying process is subjected to dust removal treatment by the waste gas treatment unit 6. The treated waste gas is circulated and discharged into the atmosphere or circulated into the hot air furnace unit 4-1 to adjust the temperature and control the oxygen of the high-temperature flue gas. At the same time, the coal powder collected by the waste gas treatment unit 6 is sent to the intermediate coal bin 5-4 for storage, and shipped through the finished coal powder shipping bin 5-3. Specifically, the waste flue gas generated after the lignite is dried is sent into the pulse bag dust collection system 6-1 by the waste gas exhaust fan 6-2 behind the pulse bag dust collection system 6-1, and after dust removal treatment, it is discharged into the atmosphere through the waste gas chimney 6-3 or enters the hot flue gas distributor 4-12 through the circulating waste gas control valve 6-4 to adjust the temperature and control the oxygen of the high-temperature flue gas. The dust emission concentration of the waste flue gas after dust removal is ≤20mg / Nm 3 In addition, the pulverized coal collected by the pulse bag dust collection system 6-1 is sent to the intermediate pulverized coal bin 5-4 of the finished product storage and shipment unit 5 by the intermediate conveying equipment, and is pneumatically conveyed into the finished pulverized coal shipping bin 5-3 of the finished product storage and shipment unit 5 for shipment.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A new type of lignite drying system based on low temperature drying, characterized in that: include: A feeding unit, including a lignite feeder, is used to mix the large pieces of lignite raw materials evenly and then feed them into the crushing unit; A crushing unit, including a lignite crusher, is used to crush the large chunks of lignite raw material into granular coal and then feed it into a pre-homogenizing unit; The pre-homogenization unit is used to homogenize the crushed lignite and to carry out homogenization and feeding, and to send the granular coal after homogenization and feeding to the drying unit; The drying unit is used to perform low-temperature aerobic drying on the homogenized coal particles and send the dried lignite to the finished product storage and shipping unit; Finished product storage and shipping unit, used for graded storage and shipping of dried lignite; The waste gas treatment unit is used to remove dust from the waste gas generated by the drying unit during drying.

2. The novel lignite drying system based on low temperature drying according to claim 1 is characterized in that: The pre-homogenization unit includes a lignite stacker and a lignite reclaimer, wherein the lignite stacker homogenizes the granular coal fed by the crushing unit to form a stockpile, and the lignite reclaimer is used to homogenize and reclaim the stockpile formed by the homogenized stockpile.

3. The novel lignite drying system based on low temperature drying according to claim 1 is characterized in that: The drying unit includes a hot air stove unit, a drying coal feeding unit and a drying machine unit, wherein: The hot blast furnace unit comprises a hot blast furnace, a hot flue gas distributor, a cold air blower, a plurality of cold air valves and a plurality of hot flue gas blowers, wherein the high-temperature hot flue gas generated by the hot blast furnace and the cold air introduced by the cold air blower enter the hot flue gas distributor for temperature adjustment and oxygen control, and then are sent into the drying unit by the hot flue gas blower through the cold air valve; The drying coal feeding unit includes a coal feeding bin, a coal powder quantitative feeder and an air-locking uniform distributor, wherein the granular coal in the coal feeding bin is fed into the air-locking uniform distributor through the coal powder quantitative feeder below the coal feeding bin, and the air-locking uniform distributor feeds the granular coal into the drying unit for drying; The dryer unit includes a fluidized grate dryer, which includes a hydraulic system and an air-locking screw conveyor, wherein the air inlet of the lower hot air chamber of the fluidized grate dryer is connected to the air outlet of the hot air furnace unit, the air outlet of the upper exhaust gas chamber of the fluidized grate dryer is connected to the exhaust gas treatment unit, the grate plate of the fluidized grate dryer is drivingly connected to the hydraulic system, and the discharge end of the fluidized grate dryer adopts an air-locking screw conveyor to deliver the dried granular coal into the finished product storage and shipping unit.

4. The novel lignite drying system based on low temperature drying according to claim 3 is characterized in that: The air outlet of the hot air furnace unit is connected to the air inlet of the dryer unit through a pipeline, and an exhaust gas heating controller is installed on the pipeline to heat the exhaust gas discharged from the dryer unit.

5. The novel lignite drying system based on low temperature drying according to claim 1 is characterized in that: The finished product storage and shipping unit includes a finished product storage warehouse, a finished lump coal shipping warehouse, a finished coal powder shipping warehouse and an intermediate coal warehouse. The granular coal dried by the drying unit is sent to the finished product storage warehouse for storage, and the granular coal in the finished product storage warehouse is sent to the finished lump coal shipping warehouse for shipping. The intermediate coal warehouse collects and stores the coal powder recovered from the exhaust gas treatment unit, and the coal powder in the intermediate coal warehouse is pneumatically conveyed into the finished coal powder shipping warehouse for shipping.

6. The novel lignite drying system based on low temperature drying according to claim 1 is characterized in that: The waste gas treatment unit includes a pulse bag dust collection system, a waste gas exhaust fan, and an intermediate conveying equipment. The waste flue gas from the drying unit is discharged after passing through the pulse bag dust collection system and the waste gas exhaust fan in sequence. The coal powder collected by the pulse bag dust collection system is transported by the intermediate conveying equipment into the finished product storage and shipping unit.

7. The novel lignite drying system based on low temperature drying according to claim 6 is characterized in that: The waste gas treatment unit also includes a circulating waste gas control valve, through which the waste gas discharged from the waste gas chimney is connected to the hot flue gas distributor in the hot blast furnace unit for adjusting the temperature and controlling the oxygen of the high-temperature hot flue gas.

8. The brown coal homogenization and drying system according to claim 5, characterized in that: It also includes a fire-fighting unit, which includes a dry powder fire-fighting system, an inert gas fire-fighting system and several explosion-proof pressure relief valves, wherein: A dry powder fire extinguishing system is provided in the drying unit; The waste gas treatment unit, drying unit, intermediate pulverized coal bin, and finished pulverized coal shipping bin are provided with an inert gas fire fighting system; A plurality of explosion-proof pressure relief valves are arranged on the pulse bag dust collecting system in the waste gas treatment unit and in the air duct connected to the drying unit.

9. The brown coal homogenization and drying system according to claim 1, characterized in that: The feeding unit is also provided with a dust collector I, which collects the coal dust generated in the feeding process of the lignite feeder and sends it to the pre-homogenization unit. The crushing unit is also provided with a dust collector II, wherein the dust collector II collects the coal dust generated in the crushing process of the lignite crusher and sends it to the pre-homogenization unit. The coal feeding bin of the drying unit is also provided with a dust collector III, which collects the coal dust generated in the conveying process and sends it into the dryer together with the raw materials.

10. A process for homogenizing and drying lignite, characterized in that: The method of homogenizing and drying lignite using the system described in any one of claims 1 to 9 comprises the following steps: S1: The raw coal in the raw coal pile in the feeding unit is homogenized for the first time according to the quality, and the raw coal after the first homogenization is sent to the crushing unit to be crushed into granular coal; S2: The crushed coal particles and the coal dust generated in the process are transported together into the pre-homogenization pile shed in the pre-homogenization unit, and a second homogenization is performed to form a homogenized stockpile; S3: The homogenized material pile is homogenized for the third time by homogenizing and feeding, and is sent to a drying unit for low-temperature aerobic drying using hot flue gas; S4: The dried granular coal is sent to the finished product storage and shipping unit for storage and shipping as lump coal; S5: The waste gas generated by the drying process is dust-removed by the waste gas treatment unit. The treated waste gas is circulated into the atmosphere for discharge or circulated into the hot air furnace unit to adjust the temperature and control the oxygen of the high-temperature flue gas. At the same time, the pulverized coal collected by the waste gas treatment unit is sent to the finished product storage and shipment unit for storage and shipment as pulverized coal.

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