CN102061211B - Integral purified integration system and process of lignite in cement production through catalytic mild pyrolysis - Google Patents

Abstract

The invention discloses an integrated lignite catalyzed mild pyrolysis upgrading integrated system and process in cement production. Dry crusher, vertical drying drum, and cyclone separator; the process includes the following steps in sequence: (1) raw lignite coal is initially crushed into coal blocks; (2) coal blocks are pre-dried and rolled into coal particles; (3) The coal particles are broken into coal powder by the drying crusher; (4) the fine coal powder is dried and upgraded by heat exchange through the vertical drying cylinder; (5) the upgraded lignite is separated from the gas in the cyclone separator to obtain the upgraded lignite product. The advantage of the present invention is that it makes full use of the waste heat in cement production, saves energy and reduces consumption, and reduces carbon dioxide emissions; the present invention utilizes the original process equipment in cement production, does not need additional equipment, has less investment and large income, and can give 2500T/ d The cement production line saves 10 million yuan.

Description

Integrated lignite catalytic mild pyrolysis upgrading integrated system and process in cement production

technical field

The invention relates to an integrated system and process for catalytic mild pyrolysis and upgrading of lignite, in particular to an integrated integrated system and process for classifying and upgrading lignite by using waste gas generated by a cement burning system.

Background technique

According to statistics, the world's lignite reserves are about 2622.9 billion tons, accounting for about 24.4% of the world's total coal reserves. China has discovered lignite resources of 210 billion tons, accounting for about 13% of China's coal reserves. Because lignite is formed very shallow from the surface, it is suitable for open-pit mining, so it is cheap. But lignite also has the following outstanding problems:

1. High moisture and low calorific value. Lignite generally has a water content between 30% and 65%, and its general calorific value is about 3000kcal/kg; 2. Low density, easy to weather, spontaneous combustion when exposed to water, and the sales radius generally does not exceed 300 kilometer. In order to solve the above problems, many companies in the world have carried out research on lignite drying and upgrading. A few processes have begun to be industrialized, and most of them are still in the experimental research stage.

There are many techniques for lignite drying and dehydration, which can be roughly divided into three types: mechanical dehydration, evaporative dehydration and non-evaporative dehydration. Mechanical dehydration technology has been widely used in coal preparation plants. Dehydration machinery such as thickeners, vibrating screens, disc filters, etc., but its processing capacity and dehydration efficiency are still difficult to meet the requirements of lignite dehydration. Evaporative dehydration is represented by fluidized bed drying technology, and mature fluidized technology is used for lignite dehydration. Most of them are relatively low-temperature drying processes, and the drying medium is hot flue gas. The flue gas is directly contacted with the lignite to make it heated, and the water evaporates and dries, so the efficiency is poor. The ignition point of lignite is low, and the coal quality is often deteriorated due to local overheating during the drying process. If the control is not good, it will cause an explosion. This type of process is relatively low temperature and does not permanently change the structure of the coal, resulting in coal with sponge-like properties that quickly absorb lost moisture once it is re-exposed to humid air or water. The non-evaporative dehydration method is represented by high-temperature and high-pressure steam drying technology. This technology requires large investment and high equipment requirements, which is difficult for enterprises to bear and it is difficult to realize industrialization.

In short, the existing lignite upgrading technology has the following disadvantages: 1. The existing lignite upgrading technology needs to provide a separate heat source, high energy consumption, increased production costs, and increased carbon dioxide emissions; 2. In the existing lignite upgrading technology During the production process, more coal tar will be produced, which will not only block the upgrading process pipeline, but also make the upgraded lignite calorific value low; , lignite upgrading is prone to explosion; 4. Some technologies require high pressure, which increases equipment investment and technical requirements. The large investment scale and high equipment requirements are difficult for enterprises to bear, and it is difficult to realize industrialization;

Contents of the invention

The first object of the present invention is to provide an integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production.

The second object of the present invention is to provide a process for upgrading lignite quality by utilizing the integrated system of catalytic mild pyrolysis upgrading of lignite in cement production.

The first object of the present invention is implemented by the following technical scheme: an integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production, which includes a cement burning system, a crusher, a pre-dryer, and a roller press , catalyst storage bin, drying crusher, vertical drying drum, cyclone separator;

Wherein the clinker cooling cooler of the cement burning system is connected with the pre-dryer through a pipeline, and the cement kiln tail of the cement burning system is connected with the drying crusher through a pipeline, and the crusher , the pre-dryer, the roller press, the drying crusher, the vertical drying cylinder, and the cyclone separator are respectively connected in sequence, and the catalyst storage bin is connected with the roller press .

It also includes a grinding device, a coal particle classification device, a pulverized coal feeding device, a dust collector and a water recovery device; wherein the cyclone separator, the coal particle classification device, and the pulverized coal feeding device are connected in sequence , the grinding device and the coal particle classifying device are connected to form a circulation loop, the cyclone separator is connected to the dust collector, the dust collector, the water recovery device, and the grinding device are respectively connected in sequence A circulation loop is formed; the pulverized coal feeding device is connected with the pulverized coal burner of the cement burning system, or the pulverized coal burner of the cement burning system is connected with the calciner.

The grinding device is any one of a ball mill, a pebble mill, a coal mill, a vertical mill or a fan mill.

The pre-dryer is any one of a rotary dryer, a vertical dryer or a tube dryer.

The second object of the present invention is implemented by the following technical scheme, a process for utilizing the integrated lignite catalytic mild pyrolysis upgrading integrated system to carry out lignite catalytic mild pyrolysis upgrading, which includes the following steps in turn: (1) The lignite raw coal is initially crushed into coal blocks; (2) the coal blocks are pre-dried and rolled into coal particles; (3) the coal particles are crushed into coal powder by a drying crusher; (4) the fine coal powder is replaced by a vertical drying cylinder Thermal drying and upgrading; (5) The upgraded lignite is separated from the gas in the cyclone separator to obtain the finished product of the upgraded lignite; wherein,

(1) The lignite raw coal is initially broken into coal lumps: the lignite raw coal containing 15-60% moisture is put into a crusher and broken into coal lumps at least less than 40mm;

(2) Coal block pre-drying and roll crushing into coal particles: the coal block crushed by the crusher enters the pre-dryer, and at the same time, the temperature of the cooler for cooling clinker from the cement burning system is at least higher than 180°C The exhaust gas is blown into the pre-dryer for pre-drying, so that the coal block is raised to at least 105°C, and the coal block and exhaust gas enter the roller press for crushing at the same time, and the catalyst in the catalyst storage bin is compressed by 0.5-6%. The mass percentage is added to the roller press to reduce the yield of coal tar. The coal lumps become coal particles, and the coal particles smaller than 0.9mm account for 20-30%, and the coal particles smaller than 2mm account for 65-80%. Coal particles larger than 2mm;

(3) The coal particles are broken into coal powder by the drying crusher: the coal particles are transported from the roller press to the drying crusher along with the gas, and the waste gas greater than 260°C from the cement kiln tail of the cement burning system enters In the drying crusher, the coal particles are further dried, crushed and dispersed in the drying crusher to obtain fine coal powder with a particle size of less than 1mm, and the fine coal powder is blown into the vertical drying cylinder along with the flue gas;

(4) The fine coal powder passes through the vertical drying drum for heat exchange drying and upgrading: the fine coal powder enters the vertical drying drum for heat exchange drying and quality upgrading, and the moisture is reduced to 5-10%;

(5) The upgraded lignite is separated from the gas in the cyclone separator to obtain an upgraded lignite product: the gas carries fine coal powder into the cyclone separator for heat exchange and gas-solid separation to obtain a moisture content of 5%-10% by mass. High-quality lignite products, and the separated gas is evacuated.

It also sequentially includes (6) waste gas treatment and utilization; (7) grinding and grading of the upgraded lignite product; (8) the upgraded lignite product with a particle size of less than 200 meshes for use by the cement firing system;

Wherein (6) waste gas treatment and utilization: the waste flue gas from the cyclone separator is dust-collected through the dust collector, and the separated fine coal powder is transported to the coal powder feeding device, and the flue gas after dust removal is passed into water for recovery device, after being dried by the water recovery device, part of it is passed into the grinding device, and the other part of the waste gas with a dust content of less than 50 mg/ ^Nm meets environmental protection requirements;

(7) Grinding and classification of upgraded lignite finished products: after the coal powder from the cyclone separator is screened by the coal particle classification device, the coal powder with a particle size greater than 200 mesh is sent to the grinding device, and the waste gas from the water recovery device is Grinding under the action of the coal particle classification device, the ground coal powder is returned to the coal particle classification device, mixed with the coal powder in the coal particle classification device, and screened again, and the exhaust gas is discharged into the dust collector to collect dust. After being screened by the coal particle classification device, the upgraded lignite finished product with a particle size of less than 200 mesh is sent to the pulverized coal feeding device;

(8) The upgraded lignite finished product with a particle size of less than 200 meshes is used for the cement burning system: the ground and graded upgraded lignite finished product is sent to the pulverized coal burner of the cement burning system through a pulverized coal feeding device, Or the pulverized coal burner and calciner of the cement firing system for combustion.

The catalyst in the step (2) is potassium carbonate, or calcium carbonate, or calcium oxide, or any one or combination of calcium hydroxide. Catalysts are added to inhibit the generation of coal tar, avoid pipeline blockage caused by the generation of coal tar, and ensure long-term stable operation of the device.

The advantages of the present invention are: (1) Utilizing cement to produce waste flue gas does not need to provide a separate heat source, which can reduce costs and save resources, and the moisture content of the upgraded lignite product is reduced to 5-10%, and the calorific value is increased to more than 4800kcal/kg. Meet the calorific value requirements of cement production for coal combustion; (2) add catalysts to inhibit the generation of coal tar during the upgrading process, avoid pipeline blockage caused by the generation of coal tar, and ensure long-term stable operation of the device; (3) utilize Preheat coal with anoxic waste flue gas from cement production, increase the temperature of coal, increase the water vapor content in the flue gas, and reduce the risk of lignite combustion and explosion in the process of upgrading lignite; (4) make the finished product of upgraded lignite Continuous grinding under the atmosphere can meet the fineness requirements of the cement burning system burner and calciner for coal powder. At the same time, the exhaust gas can be reasonably treated to reduce the dust content and temperature of the exhaust gas, so that it can meet the emission standards and make the cement production process more efficient. (5) the present invention does not require special technical requirements equipment, has low investment and large income, and can save 10 million yuan for a 2500T/d cement production line every year.

Description of drawings

Fig. 1 is a schematic diagram of embodiment 1, an integrated lignite catalytic light pyrolysis upgrading integrated system in cement production.

Fig. 2 is a schematic diagram of the technological process of using the integrated brown coal catalytic mild pyrolysis upgrading integrated system in the cement production of Example 1 to carry out lignite catalytic mild pyrolysis upgrading in Example 2.

Fig. 3 is a schematic diagram of embodiment 3, an integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production.

Fig. 4 is a schematic diagram of the process flow of using the integrated lignite catalytic mild pyrolysis upgrading integrated system in the cement production of Example 3 to carry out lignite catalytic mild pyrolysis upgrading in Example 4.

Multi-stage preheater 1, decomposition furnace 2, cement burning system 3, pulverized coal burner 4, cooler 5, crusher 6, pre-dryer 7, roller press 8, drying crusher 9, vertical drying Dry cylinder 10, cyclone separator 11, grinding device 12, coal particle classification device 13, coal powder feeding device 14, dust collector 15, coal bunker 16, water recovery device 17, catalyst storage bin 18.

Detailed ways

Embodiment 1: As shown in Figure 1, the integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production includes a cement burning system 3, a crusher 6, a pre-dryer 7, a roller press 8, Catalyst storage bin 18, drying crusher 9, vertical drying cylinder 10, cyclone separator 11, coal bunker 16;

Among them, the cooler for cooling the clinker of the cement burning system 3 - the cooler 5 is connected to the pre-dryer 7 through the pipeline, and the cement kiln tail of the cement burning system 3 - the multi-stage preheater 1 is connected to the drying crusher through the pipeline 9 connections, crusher 6, pre-dryer 7, roller press 8, drying crusher 9, vertical drying cylinder 10, cyclone separator 11, coal bunker 16 are connected in sequence, catalyst storage bin 18 is connected with the roller press 8 phase connections.

The cement burning system 3 is a suspension preheater kiln, which includes a multi-stage preheater 1, a decomposition furnace 2, a pulverized coal burner 4, and a cooler 5, wherein the cooler for cooling the clinker of the cement burning system 3 is The cooler 5 and the cement kiln tail of the cement burning system 3 are multi-stage preheaters 1 .

The pre-dryer 7 is a rotary dryer.

Using the above-mentioned integrated lignite catalytic mild pyrolysis and upgrading integrated system in cement production to carry out the process of lignite catalytic mild pyrolysis upgrading, which sequentially includes the following steps:

(1) The lignite raw coal is initially broken into coal lumps: the lignite raw coal containing 15-60% moisture is put into the crusher 6 and broken into coal lumps at least less than 40mm;

(2) Coal block pre-drying and rolling crushing into coal particles: the coal block crushed by the crusher 6 enters the pre-dryer 7, and at the same time, the waste gas from the cooler 5 of the cement burning system 3 is at least higher than 180°C Blow into the pre-dryer 7 for pre-drying, so that the coal block is raised to at least 105°C, and the coal block and waste gas enter the roller press 8 to be crushed at the same time, and the catalyst in the catalyst storage bin 18 is sent to the roller press 8 at a rate of 0.5% by mass. Internally added, coal particles smaller than 0.9mm account for 20-30%, coal particles smaller than 2mm account for 65-80%, and the remaining coal particles are larger than 2mm; the total catalyst is a mixture of potassium carbonate, calcium carbonate and calcium oxide in any ratio.

(3) The coal particles are broken into coal powder by the drying crusher 9: the coal particles are transported from the roller press 8 to the drying crusher 9 along with the gas, and the coal particles from the multi-stage preheating device 1 of the cement burning system 3 are more than 260 ℃ The waste gas enters the drying crusher 9, and the coal particles are further dried, crushed and dispersed in the drying crusher 9 to obtain fine coal powder with a particle size of less than 1 mm, which is blown into the vertical drying cylinder 10 along with the flue gas;

(4) The fine coal powder passes through the vertical drying cylinder 10 for heat exchange drying and upgrading: the fine coal powder enters the vertical drying cylinder 10 for heat exchange drying and quality upgrading, and the moisture is reduced to 5-10%;

(5) The upgraded lignite is separated from the gas in the cyclone separator 11 to obtain an upgraded lignite product: the gas carries fine coal powder into the cyclone separator 11 for heat exchange and gas-solid separation to obtain a moisture content of 5%-10% by mass % upgraded lignite finished product, and the upgraded lignite finished product is transported in the coal bunker 16, and the separated gas is emptied.

Embodiment 2: Integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production, which includes cement burning system 3, crusher 6, pre-dryer 7, roller press 8, catalyst storage bin 18, oven Dry crusher 9, vertical drying cylinder 10, cyclone separator 11, grinding device 12, coal particle classification device 13, coal powder feeding device 14, dust collector 15 and water recovery device 17; wherein the cement firing system 3 The cooler for cooling the clinker—the cooler 5 is connected to the pre-dryer 7 through pipelines, the cement kiln tail of the cement firing system 3—the multistage preheater 1 is connected to the drying crusher 9 through pipelines, and the crushers 6, The pre-dryer 7, roller press 8, drying crusher 9, vertical drying cylinder 10, and cyclone separator 11 are respectively connected in sequence, the catalyst storage bin 18 is connected with the roller press 8, the cyclone separator 11, and the coal particle The classifying device 13 and the pulverized coal feeding device 14 are respectively connected successively, the grinding device 12 and the coal particle classifying device 13 are connected to form a circulation loop, the cyclone separator 11 is connected with the dust collector 15, the dust collector 15, the water recovery device 17, The grinding devices 12 are respectively connected in sequence to form a circulation loop; the pulverized coal feeding device 14 is connected with the pulverized coal burner 4 and the calciner 2 of the cement firing system 3 .

The cement firing system 3 is a new type dry process kiln firing system, which includes a multi-stage preheater 1, a cooler 5, a calciner 2 and a pulverized coal burner 4, and a cooler for cooling clinker in the cement firing system 3 It is the cooler 5 of the new dry kiln firing system, and the cement kiln tail of the cement firing system 3 is the multi-stage preheater 1 of the new dry kiln firing system.

The pre-dryer 7 is a vertical dryer.

The grinding device 12 is a ball mill.

Using the above-mentioned integrated brown coal catalytic mild pyrolysis upgrading integrated system in cement production to carry out the lignite catalytic mild pyrolysis upgrading process, which includes the following steps in sequence:

(1) The lignite raw coal is initially broken into coal lumps: the lignite raw coal containing 15-60% moisture is put into the crusher 6 and broken into coal lumps at least less than 40mm;

(2) Coal block pre-drying and rolling crushing into coal particles: the coal block crushed by the crusher 6 enters the pre-dryer 7, and at the same time, the waste gas from the cooler 5 of the cement burning system 3 is at least higher than 180°C Blow into the pre-dryer 7 for pre-drying, so that the coal block is raised to at least 105°C, and the coal block and waste gas enter the roller press 8 to be crushed simultaneously, and the catalyst in the catalyst storage bin 18 is sent to the roller press 8 by 6% by mass. Internally added, coal particles smaller than 0.9mm account for 20-30%, coal particles smaller than 2mm account for 65-80%, and the remaining coal particles are larger than 2mm; the total catalyst is a mixture of potassium carbonate, calcium carbonate and calcium oxide in any ratio.

(3) The coal particles are broken into coal powder by the drying crusher 9: the coal particles are transported from the roller press 8 to the drying crusher 9 along with the gas, and the coal particles from the multi-stage preheating device 1 of the cement burning system 3 are more than 260 ℃ The waste gas enters the drying crusher 9, and the coal particles are further dried, crushed and dispersed in the drying crusher 9 to obtain fine coal powder with a particle size of less than 1 mm, which is blown into the vertical drying cylinder 10 along with the flue gas;

(4) The fine coal powder passes through the vertical drying cylinder 10 for heat exchange drying and upgrading: the fine coal powder enters the vertical drying cylinder 10 for heat exchange drying and quality upgrading, and the moisture is reduced to 5-10%;

(5) The upgraded lignite is separated from the gas in the cyclone separator 11 to obtain an upgraded lignite product: the gas carries fine coal powder into the cyclone separator 11 for heat exchange and gas-solid separation to obtain a moisture content of 5%-10% by mass % upgraded lignite finished product, and the upgraded lignite finished product is sent to the coal particle classification device 13, and the separated gas is passed into the dust collector 15.

(6) Waste gas treatment and utilization: the waste flue gas from the cyclone separator 11 is collected by the dust collector 15, and the separated fine coal powder is transported to the coal powder feeding device 14, and the dust-removed flue gas is passed into the water recovery device 17 After being dried by the water recovery device 17 ^, part of it is passed into the grinding device 12, and the other part is emptied of waste gas with a dust content of less than 50 mg/Nm that meets environmental protection requirements;

(7) Grinding and classification of upgraded lignite finished products: after the coal powder from the cyclone separator 11 is screened by the coal particle classification device 13, the coal powder with a particle size greater than 200 mesh is sent into the grinding device 12, and the waste gas from the water recovery device 17 The pulverized coal after grinding is returned to the coal particle classification device 13, mixed with the coal powder in the coal particle classification device 13, and screened again, and the waste gas is discharged into the dust collector 15 to collect dust, and is screened by the coal particle classification device 13 The finished product of upgraded lignite with a particle size of less than 200 meshes is sent to the pulverized coal feeding device 14;

(8) The upgraded lignite finished product with a particle size of less than 200 meshes is used for the cement burning system 3: the pulverized coal burner 4 and the pulverized coal burner 4 of the cement burning system 3 are fed with the pulverized coal feeding device 14 through the pulverized coal feeding device 14 and the upgraded lignite finished product is sent to the cement burning system 3 Calciner 2, for combustion use.

The catalyst in the step (2) is a mixture of calcium carbonate, calcium oxide and calcium hydroxide in any ratio.

Embodiment 3: in the integration system of lignite catalytic mild pyrolysis upgrading in the cement production of embodiment 1, the cement firing system can also be a Liboer kiln, which includes a Liboer preheater, a cooling machine and a coal kiln. Powder burner, wherein the clinker cooling cooler of the cement firing system 3 is the cooler of the Liber kiln, and the cement kiln tail of the cement firing system 3 is the Liber preheater.

The pre-dryer 7 is a vertical dryer.

In step (2) of Example 1, the catalyst in the catalyst storage bin 18 can also be added to the roller press 8 at a rate of 3% by mass.

Example 4: In Example 2, in the integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production, the cement firing system can also be a wet process kiln with a heater, which includes a heater, a cooler and a pulverized coal combustion Among them, the clinker cooling cooler of the cement firing system 3 is a cooler of a wet kiln with a heater, and the tail of the cement kiln of the cement firing system 3 is a heater of a wet kiln with a heater. The pulverized coal feeding device 14 is connected with the pulverized coal burner 4 of the cement burning system 3 .

The pre-dryer 7 is a tubular dryer.

The grinding device 12 is a fan mill.

In step (2) of Example 2, the catalyst in the catalyst storage bin 18 can also be added to the roller press 8 at a rate of 4% by mass.

Claims (5)

1. An integrated lignite catalytic mild pyrolysis upgrading integrated system in cement production is characterized by comprising a cement firing system, a crusher, a pre-dryer, a roller press, a catalyst storage bin, a drying crusher, a vertical drying cylinder and a cyclone separator;

the cooler for cooling clinker of the cement burning system is connected with the pre-dryer through a pipeline, the cement kiln tail of the cement burning system is connected with the drying crusher through a pipeline, the crusher, the pre-dryer, the roller press, the drying crusher, the vertical drying cylinder and the cyclone separator are sequentially connected, and the catalyst storage bin is connected with the roller press.

2. The integrated lignite catalytic mild pyrolysis upgrading system in cement production according to claim 1, further comprising a grinding device, a coal particle grading device, a pulverized coal feeding device, a dust collector and a water recovery device; the cyclone separator, the coal particle grading device and the coal powder feeding device are sequentially connected, the grinding device and the coal particle grading device are connected into a circulation loop, the cyclone separator is connected with the dust collector, the water recovery device and the grinding device are sequentially connected to form a circulation loop; the pulverized coal feeding device is connected with the pulverized coal burner of the cement burning system or the pulverized coal burner of the cement burning system and the decomposing furnace.

3. The integrated lignite catalytic mild pyrolysis upgrading system in cement production according to claim 1, wherein the pre-dryer is any one of a rotary dryer, a vertical dryer or a tubular dryer.

4. A process for carrying out lignite catalytic mild pyrolysis upgrading by utilizing an integrated lignite catalytic mild pyrolysis upgrading integrated system is characterized by sequentially comprising the following steps of: (1) primarily crushing raw lignite into coal blocks; (2) pre-drying and rolling and crushing the coal blocks into coal particles; (3) crushing the coal particles into coal powder by a drying crusher; (4) the fine coal powder is subjected to heat exchange drying and quality improvement through a vertical drying cylinder; (5) separating the upgraded lignite from gas in a cyclone separator to obtain an upgraded lignite finished product; wherein,

(1) primarily crushing raw lignite into coal blocks: putting raw lignite containing 15-60% of moisture into a crusher to be crushed into coal blocks at least smaller than 40 mm;

(2) pre-drying and rolling and crushing coal blocks into coal particles: feeding the coal blocks crushed by the crusher into a pre-dryer, blowing waste gas at least higher than 180 ℃ from a cooler for cooling clinker of a cement sintering system into the pre-dryer for pre-drying so as to at least increase the temperature of the coal blocks to 105 ℃, feeding the coal blocks and the waste gas into a roller press for crushing, and adding a catalyst in a catalyst storage bin into the roller press according to the mass percentage of 0.5-6% to obtain 20-30% of coal particles smaller than 0.9mm, 65-80% of coal particles smaller than 2mm and the rest of coal particles larger than 2 mm; the catalyst is any one or the combination of more of potassium carbonate, calcium oxide or calcium hydroxide;

(3) crushing the coal particles into coal powder by a drying crusher: conveying the coal particles with gas from the roller press to a drying crusher, feeding waste gas with the temperature of more than 260 ℃ from the tail of a cement kiln of the cement burning system into the drying crusher, further drying, crushing and dispersing the coal particles in the drying crusher to obtain fine coal powder with the particle size of less than 1mm, and blowing the fine coal powder into a vertical drying cylinder along with flue gas;

(4) the fine coal powder is subjected to heat exchange drying and quality improvement through a vertical drying cylinder: feeding the fine coal powder into the vertical drying cylinder, and performing heat exchange drying and quality improvement until the water content is reduced to 5-10%;

(5) separating the upgraded lignite from gas in a cyclone separator to obtain an upgraded lignite finished product: the gas carrying the fine coal powder enters a cyclone separator, heat exchange and gas-solid separation are carried out to obtain an upgraded lignite finished product with the moisture content of 5-10% by mass, and the separated gas is emptied.

5. The process for upgrading the lignite catalytic mild pyrolysis by utilizing the integrated lignite catalytic mild pyrolysis upgrading system according to claim 4, which is characterized by further comprising (6) waste gas treatment and utilization; (7) grinding and grading the upgraded lignite finished product; (8) the upgraded lignite finished product with the granularity of less than 200 meshes is used by the cement burning system;

wherein the (6) exhaust gas treatment and utilization: the waste flue gas from the cyclone separator is collected by a dust collector, the separated fine coal powder is conveyed to a coal powder feeding device, the flue gas after dust removal is introduced into a water recovery device, and one part of the flue gas after drying by the water recovery device is introduced into a grinding deviceThe other part of the dust content is less than 50mg/Nm³Exhaust gas evacuation meeting the environmental protection requirement is achieved;

(7) grinding and grading the upgraded lignite finished product: after the pulverized coal from the cyclone separator is screened by a coal particle grading device, the pulverized coal with the particle size of more than 200 meshes is sent to the grinding device and ground under the action of the waste gas from the water recovery device, the ground pulverized coal returns to the coal particle grading device to be mixed with the pulverized coal in the coal particle grading device, screening is carried out again, the waste gas is discharged into the dust collector to collect dust, and the upgraded lignite finished product with the particle size of less than 200 meshes is sent to the pulverized coal feeding device after being screened by the coal particle grading device;

(8) the upgraded lignite finished products with the granularity of less than 200 meshes are supplied to the cement burning system for utilization: and feeding the ground and graded upgraded lignite finished products into a pulverized coal burner of the cement burning system or the pulverized coal burner and a decomposing furnace of the cement burning system through a pulverized coal feeding device for combustion.

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