A new type of coal briquette production method without recycling and a coal briquette production line

Abstract

The present invention relates to the field of briquette production technology, and in particular to a briquette production line, comprising a drum screen, a crusher, a dehydrator, a mixer, a briquette press, a dryer, and a preheating and drying integrated furnace arranged in sequence, wherein the flue gas from the burner of the preheating and drying integrated furnace is connected in sequence to a first heat exchanger, a denitrification device, a dehydrator, and a desulfurization and dust removal device; the first heat exchanger is provided with a flue gas pipeline and an air pipeline, the flue gas pipeline is connected to the combustion flue gas of the preheating and drying integrated furnace, and the air pipeline is connected to the air and the dryer. Based on the existing process flow, the present invention adds anaerobic dehydration before stirring, the heat for anaerobic dehydration comes from the anaerobic flue gas burned in the preheating and drying integrated furnace, and the flue gas generated by the combustion of the preheating and drying integrated furnace is treated by a heat exchange-denitrification-secondary heat exchange-desulfurization method, which fully utilizes the heat of the flue gas while seamlessly connecting with the desulfurization and denitrification process.

Description

Technical Field

[0001] The present invention relates to the technical field of briquette production, and in particular to a novel non-recovery briquette production method and a briquette production line. Background Art

[0002] my country's resource characteristics of being "rich in coal, poor in oil, and limited in natural gas" will ensure that coal will continue to hold a significant share of my country's energy consumption for a considerable period of time. While clean heating methods like "coal-to-gas" and "coal-to-electricity" have proven effective, they are unaffordable due to the high investment and costs. This is particularly true in the vast rural areas of northern China, where economic and geographical constraints make them difficult to implement in the short term. Decentralized coal heating remains a necessity for some farmers in remote areas. Statistics show that farmers consume 750 million tons of coal annually through scattered burning and small and medium-sized boilers. These burning generates SO2 and soot emissions that are 4-8 times greater than burning thermal coal of the same raw material, and PM2.5 emissions that are 30-50 times greater than those from pulverized coal boilers in power plants. Currently, total pollutant emissions are increasing, the scope of pollution continues to expand, and environmental degradation is intensifying. In some areas, environmental pollution and ecological damage have become significant factors hindering economic development, undermining social stability, and threatening public health. The most practical and feasible way to control coal smoke pollution and improve atmospheric quality in my country is to develop clean coal technology. Coal briquette technology is one of the clean coal technologies that requires low investment, has quick results, and is in line with China's national conditions.

[0003] Actively promoting the use of clean coal fuel aligns with national industrial policies, aligns with economic development trends, and also has broad market demand. In April 2019, the National Energy Administration issued guidance advocating for the replacement of low-quality bulk coal with clean coal, advocating for the use of electricity where appropriate, gas where appropriate, and coal where appropriate, tailored to local conditions.

[0004] Practice has shown that by adding sintering sulfur-fixing agents to pulverized coal to form clean coal, the sulfur-fixing rate can reach about 65%. Burning clean coal can improve the thermal efficiency of the boiler, increase the combustion time, and achieve the purpose of reducing the emission of nitrogen oxides and sulfur dioxide and reducing fuel consumption.

[0005] The promotion and use of clean coal will effectively reduce the total amount of pollutant emissions from coal combustion and achieve the goal of improving air quality. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a novel method for producing shaped coal without recycling and a shaped coal production line.

[0007] The technical solution adopted by the present invention is: a method for producing a new type of coal briquette without recycling, which is characterized by comprising the following steps:

[0008] Step 1: Screening low-rank coal with a particle size of less than 80 mm;

[0009] Step 2: crush the low-rank coal screened in step 1 to a particle size of less than 3 mm;

[0010] Step 3: The raw materials obtained in step 2 are transported to a dehydrator;

[0011] Step 4: The dehydrated raw materials are transported to the mixer;

[0012] Step 5: Hot pressing the stirred raw materials into shape;

[0013] Step 6: The hot-pressed balls are dried for the first time until the moisture content is below 4%;

[0014] Step 7: The briquettes are dried and cooled in a preheating and drying furnace to form clean briquettes.

[0015] The flue gas generated by combustion and heating in the preheating and drying integrated furnace is passed through a first heat exchanger to heat air, and the heated air is used for the first drying in step 6;

[0016] The flue gas generated by the combustion and heating of the preheating and drying integrated furnace directly dehydrates the raw materials in step 3 without oxygen;

[0017] The flue gas generated by combustion and heating in the preheating and drying integrated furnace passes through the first heat exchanger, the denitrification device, the dehydrator, and the dust removal device in sequence.

[0018] The method for producing a novel type of coal briquette without recycling is characterized in that: in the step 4, a sintering sulfur-fixing agent is added during stirring and the mixture is fully mixed.

[0019] The novel non-recovery coal production method is characterized in that the preheating and drying integrated furnace is divided into a preheating section, a drying section and a cooling section from top to bottom, wherein the cooling section adopts an inert medium circulation cooling, and the inert medium absorbs heat in the cooling section and releases heat in the second heat exchanger.

[0020] The novel non-recovery coal production method is characterized in that the second heat exchanger is connected to softened water.

[0021] The novel non-recovery coal production method is characterized in that the combustible gas generated by pyrolysis in the drying section of the preheating and drying integrated furnace is respectively provided to the burner or heating device of the preheating and drying integrated furnace for combustion.

[0022] A briquette production line comprises a drum screen, a crusher, a mixer, a briquette press, and a drying device arranged in sequence, a dehydrator being arranged between the crusher and the mixer, and the drying device comprising a dryer and a preheating and drying integrated furnace arranged in sequence;

[0023] The flue gas from the burner of the preheating and drying integrated furnace is sequentially connected to the first heat exchanger, the denitrification device, the dehydrator and the desulfurization and dust removal device;

[0024] The first heat exchanger is provided with a flue gas pipeline and an air pipeline. The flue gas pipeline is connected to the combustion flue gas of the preheating and drying integrated furnace, and the air pipeline is connected to the air and the dryer.

[0025] The described briquette production line is characterized in that the interior of the preheating and drying integrated furnace is divided into a preheating section, a drying section and a cooling section from top to bottom. The cooling section of the preheating and drying integrated furnace is filled with an inert medium and matched with an external circulation pipeline, so that the inert medium in the cooling section of the preheating and drying integrated furnace passes through the second heat exchanger and then returns to the cooling section.

[0026] The briquette production line is characterized in that the second heat exchanger is connected to softened water, and a dehumidification device is also installed on the external circulation pipeline.

[0027] On the basis of the existing process flow, the present invention adds anaerobic dehydration before stirring. The heat of anaerobic dehydration comes from the oxygen-free flue gas burned in the preheating and drying integrated furnace. The temperature of the oxygen-free flue gas generated by combustion is high, and the temperature of the currently commonly used denitrification process is higher than that of the desulfurization process. Therefore, the flue gas generated by the combustion in the preheating and drying integrated furnace is treated by heat exchange-denitrification-secondary heat exchange-desulfurization, which fully utilizes the heat of the flue gas while seamlessly connecting with the desulfurization and denitrification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process of the present invention.

[0029] In the figure, 1-drum screen, 2-crusher, 3-dehydrator, 4-mixer, 5-briquette machine, 6-dryer, 7-preheating and drying integrated furnace, 8-first heat exchanger, 9-denitrification device, 10-desulfurization and dust removal device, 11-heating device, 12-second heat exchanger, 13-dehumidification device. DETAILED DESCRIPTION

[0030] like Figure 1As shown, a briquette production line includes a drum screen 1, a crusher 2, a dehydrator 3, a mixer 4, a briquette press 5, a dryer 6, and a preheating and drying integrated furnace 7, which are arranged in sequence. The interior of the preheating and drying integrated furnace 7 is divided into a preheating section, a drying section, and a cooling section from top to bottom. The oxygen-free flue gas produced by the burner of the preheating and drying integrated furnace 7 is connected in sequence to the flue gas pipeline of the first heat exchanger 8, the denitrification device 9, the dehydrator 3, and the desulfurization and dust removal device 10. The heating device 11 is a boiler or other burner. The high-temperature flue gas containing water vapor produced in the preheating section of the preheating and drying integrated furnace 7 is connected in sequence to the dryer 6 and the heating device 11. The combustible gas generated by pyrolysis in the drying section of the preheating and drying integrated furnace 7 is connected to the combustion chambers of the burner of the preheating and drying integrated furnace 7 and the heating device 11, respectively. The oxygen-free high-temperature flue gas produced by the burner of the preheating and drying integrated furnace 7 and the heating device 11 is connected in sequence to the first heat exchanger 8, the denitrification device 9, the dehydrator 10, and the desulfurization and dust removal device 10. The cooling section of the preheating and drying integrated furnace 7 is filled with an inert medium and equipped with an external circulation pipeline. The inert medium in the cooling section of the preheating and drying integrated furnace 7 passes through the second heat exchanger 12 and then returns to the cooling section. The second heat exchanger 12 is connected to softened water. A dehumidifier is also installed in the external circulation pipeline to separate the water vapor in the inert medium. The separated high-temperature water vapor is passed into the dryer 6. In addition to the flue gas pipeline, the first heat exchanger 8 is also equipped with an air pipeline. The air pipeline inlet is open to the outside and the outlet is connected to the dryer 6. The gas outlet of the dryer 6 is connected to the combustion chamber of the heating device 11.

[0031] When the production line is in use, low-rank coal with a particle size of less than 80mm is first screened using a drum screen as raw material. The raw material is then crushed to a particle size of less than 3mm using a crusher. The raw material is then conveyed to a dehydrator via a metered feeding device. After dehydration, it is sent to a mixer where a heat-sintering sulfur-fixing agent is heated and thoroughly mixed. The coal then enters a briquette press where it is hot-pressed into balls. The balls are then conveyed to a drying unit where they are dried until the moisture content drops below 4%. They are then conveyed to a preheating and drying furnace via a vertical elevator. After preheating, drying, and cooling, clean coal briquettes are finally formed. The combustible gases generated by pyrolysis in the drying section of the preheating and drying furnace are supplied to the furnace's burner or heating unit for combustion. The high-temperature flue gas generated by combustion in the preheating and drying furnace and the heating unit first heats the air in the first heat exchanger before entering the denitrification unit for denitrification. The high-temperature flue gas then enters the dehydrator for oxygen-free dehydration of the coal powder. The desulfurization and dust removal unit removes sulfur and dust before finally discharging the coal to meet emission standards. The cooling section of the preheating and drying furnace uses a circulating cooling method. An inert medium is injected into the cooling section. During circulation, the inert medium absorbs heat in the cooling section, heats the softened water in the second heat exchanger, and carries some water vapor back to the cooling section. In the next cycle, the high-temperature water vapor is separated and enters the dryer to heat the interior. Normal-temperature air, heated in the first heat exchanger, enters the dryer, heating the interior and gradually removing moisture from the pellets. The hot air carrying water vapor is then treated together with the water vapor from the preheating and drying furnace before being discharged in compliance with emission standards.

[0032] In this embodiment, the specific structures of some devices and the negative pressure device for flue gas circulation are omitted. The above omissions are conventional technical means in this field and therefore do not affect the integrity of the technical content.

Claims

1. A method for producing a new type of coal briquette without recycling, characterized by: The steps include: Step 1: Screening low-rank coal with a particle size of less than 80 mm; Step 2: crush the low-rank coal screened in step 1 to a particle size of less than 3 mm; Step 3: The raw material obtained in step 2 is transported to a dehydrator; Step 4: The dehydrated raw materials are transported to the mixer; Step 5: Hot pressing the stirred raw materials into shape; Step 6: The hot-pressed molded balls are dried for the first time until the moisture content drops below 4%; Step 7: The briquettes are dried and cooled in a preheating and drying furnace to form clean briquettes. The flue gas generated by combustion and heating in the preheating and drying integrated furnace is passed through a first heat exchanger to heat air, and the heated air is used for the first drying in step 6; The flue gas generated by the combustion and heating of the preheating and drying integrated furnace directly dehydrates the raw materials in step 3 without oxygen; The flue gas generated by combustion and heating in the preheating and drying integrated furnace passes through the first heat exchanger, the denitrification device, the dehydrator, and the desulfurization and dust removal device in sequence; The preheating and drying integrated furnace is divided into a preheating section, a drying section and a cooling section from top to bottom, wherein the cooling section adopts an inert medium circulation cooling, the inert medium absorbs heat in the cooling section and releases heat in the second heat exchanger; The second heat exchanger is connected to softened water.

2. The method for producing a novel non-recovery coal briquette according to claim 1, wherein: In step 4, a sintering sulfur-fixing agent is added during stirring and the mixture is thoroughly mixed.

3. The method for producing a novel non-recovery coal briquette according to claim 1, wherein: The combustible gas generated by pyrolysis of the drying section of the preheating and drying integrated furnace is respectively provided to the burner or heating device of the preheating and drying integrated furnace for combustion.

4. A briquette production line comprising a drum screen, a crusher, a mixer, a briquette press, and a drying device arranged in sequence, characterized in that: A dehydrator is provided between the crusher and the mixer, and the drying device comprises a dryer and a preheating and drying integrated furnace which are arranged in sequence; The flue gas from the burner of the preheating and drying integrated furnace is sequentially connected to the first heat exchanger, the denitrification device, the dehydrator and the desulfurization and dust removal device; The first heat exchanger is provided with a flue gas pipeline and an air pipeline, the flue gas pipeline is connected to the combustion flue gas of the preheating and drying integrated furnace, and the air pipeline is connected to the air and the dryer; The preheating and drying integrated furnace is divided into a preheating section, a drying section, and a cooling section from top to bottom. The cooling section of the preheating and drying integrated furnace is filled with an inert medium and matched with an external circulation pipeline, so that the inert medium in the cooling section of the preheating and drying integrated furnace passes through the second heat exchanger and then returns to the cooling section; The second heat exchanger is connected to softened water, and a dehumidification device is also installed on the external circulation pipeline.

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