Low-rank coal dry distillation method and dry distillation system

Abstract

The invention discloses a low-rank coal dry distillation method and dry distillation system. The low-rank coal dry distillation method comprises the following steps: S1, upgrading low-rank coal added with oil-rich waste to form oil-rich coal; s2, pressing the oil-rich coal into briquette coal; and S3, carrying out high-temperature dry distillation on the briquette coal. According to the low-rank coal dry distillation method and the dry distillation system, the oil-rich waste is added in the low-rank coal upgrading stage, oil can be separated out in advance, the oil is effectively prevented from being separated out in the high-temperature dry distillation stage, coking is avoided, meanwhile, the strength of briquette coal is improved, and the briquette coal can be further prevented from being broken and coked.

Description

Technical Field

[0001] The present invention relates to the technical field of dry distillation, and in particular to a low-rank coal dry distillation method and a dry distillation system. Background Art

[0002] Low-rank coal has high water content and volatile matter content, so it usually needs to be upgraded before it can be used for dry distillation. Since low-rank coal is usually in powder form, oil-rich waste is usually added to the upgraded pulverized coal at a ratio of 10%-30%. The oil-rich waste is usually oil sludge or oil residue or a mixture of the two to assist in pressing the pulverized coal into shape. If the ratio is exceeded, it is very easy for the shaped coal to coke and clog in the dry distillation furnace. Reducing the oil sludge and oil residue requires adding more binder, which increases the cost. The shaped coal with added oil sludge and oil residue is easy to produce oil and more likely to coke during dry distillation. Even if it is added at a certain predetermined ratio for a long time, the shaped coal will coke and clog in the dry distillation furnace. Therefore, structures and monitoring measures to prevent coking are usually set in the dry distillation furnace, making the structure of the dry distillation furnace complex and difficult to operate. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a low-rank coal dry distillation method and a dry distillation system capable of reducing and lowering coking in a high-temperature dry distillation furnace.

[0004] In order to solve the above problems, the present invention provides a low-rank coal dry distillation method, which comprises the following steps:

[0005] Step S1, upgrading low-rank coal added with oil-rich waste to form oil-rich coal;

[0006] Step S2, pressing the oil-rich coal into coal briquettes;

[0007] Step S3, subjecting the briquette to high-temperature dry distillation.

[0008] Furthermore, step S1 includes the following steps:

[0009] Step S11, adding oil-rich waste to low-rank coal;

[0010] Step S12, performing low-temperature dehydration treatment on the low-rank coal containing oil-rich waste;

[0011] In step S13, the dehydrated low-rank coal containing oil-rich waste is subjected to medium-temperature oxygen-free dry distillation to obtain oil-rich coal.

[0012] Furthermore, in step S11, the oil-rich waste and the low-rank coal are simultaneously added to a quality upgrading unit for low-temperature dehydration and medium-temperature oxygen-free dry distillation.

[0013] Furthermore, in step S12, low-temperature flue gas is used to directly or indirectly heat the low-rank coal containing oil-rich waste for dehydration.

[0014] Furthermore, in step S13, medium-temperature flue gas is used to indirectly heat and dry-dry the low-rank coal containing oil-rich waste after dehydration.

[0015] Furthermore, step S2 includes the following steps:

[0016] Step S21, mixing the oil-rich coal and the binder according to a ratio;

[0017] Step S22, then using a pressing machine to press the oil-rich coal into briquettes;

[0018] Step S23, drying the briquettes through a drying device.

[0019] In order to solve the above problems, the present invention also provides a low-rank coal dry distillation system, which includes a quality improvement unit for removing moisture and volatilization of low-rank coal added with oil-rich waste, a briquette processing mechanism for pressing the upgraded coal into briquette and drying the briquette, and a high-temperature dry distillation device for dry distilling the pressed coal. The quality improvement unit includes a low-temperature dehydration device for low-temperature dehydration, a cooling device for removing moisture from the flue gas discharged by the low-temperature dehydration device, a denitrification device for denitrifying the flue gas, and a high-temperature dry distillation device for dry distilling the pressed coal. A medium-temperature oxygen-free dry distillation device for low-temperature oxygen-free dry distillation, and a medium-temperature temperature regulating device for increasing the temperature of flue gas. The flue gas generated by the high-temperature dry distillation device is sent to a briquette processing mechanism to dry the briquette. The flue gas discharged by the medium-temperature oxygen-free dry distillation device and the briquette processing mechanism are both sent to the medium-temperature temperature regulating device. After the medium-temperature temperature regulating device increases the temperature of the flue gas, part of the flue gas is sent to the medium-temperature oxygen-free dry distillation device, and the remaining part of the flue gas is sent to the denitrification device. The flue gas treated by the cooling device is sent to the denitrification device, and the denitrification device sends the denitrified flue gas to a low-temperature dehydration device.

[0020] Furthermore, it also includes a cold drum device for removing coal tar from raw gas and a purification device for purifying raw gas. The raw gas generated by the medium-temperature oxygen-free distillation device and the raw gas generated by the high-temperature oxygen-free distillation device are respectively sent to the corresponding cold drum device or to the same cold drum device. The raw gas from which coal tar is removed is sent to the purification device for purification to obtain coal gas, and part of the coal gas is sent to the medium-temperature temperature regulation device and the high-temperature oxygen-free distillation device through a pipeline.

[0021] To solve the above problems, the present invention also provides a low-rank coal dry distillation system, which includes a quality improvement unit for removing moisture and volatilization from low-rank coal added with oil-rich waste, a briquette processing mechanism for pressing the upgraded coal into shapes, and a high-temperature dry distillation device for dry distilling the pressed coal. The quality improvement unit includes an integrated dry distillation furnace for first low-temperature dehydration and then medium-temperature dry distillation, and a medium-temperature temperature regulating device for regulating the flue gas temperature. The flue gas generated by the high-temperature dry distillation device is sent to the briquette processing mechanism to dry the briquette. The flue gas discharged from the integrated dry distillation furnace and the briquette processing mechanism is sent to the medium-temperature temperature regulating device. The medium-temperature temperature regulating device raises the flue gas temperature and then sends it to the medium-temperature oxygen-free dry distillation device.

[0022] Furthermore, it also includes a cold drum device for removing coal tar from raw gas and a purification device for purifying raw gas. The raw gas generated by the integrated retort furnace and the raw gas generated by the high-temperature oxygen-free retort device are respectively sent to the corresponding cold drum device or to the same cold drum device. The raw gas from which the coal tar is removed is sent to the purification device for purification to obtain coal gas, and part of the coal gas is sent to the medium-temperature temperature regulating device and the high-temperature oxygen-free retort device through a pipeline.

[0023] The low-rank coal dry distillation method and dry distillation system of the present invention add oil-rich waste during the low-rank coal upgrading stage, which can precipitate oil in advance, effectively avoiding the precipitation of oil in the high-temperature dry distillation stage and thus avoiding coking. Since the proportion of oil-rich waste can be increased, the strength of the resulting briquette is improved, which is 10 times the strength of the briquette produced by the existing method. It is not easy to break in the high-temperature oxygen-free dry distillation device, which can further avoid the breakage and coking of the briquette. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a preferred embodiment of the low-rank coal dry distillation system of the present invention.

[0025] Figure 2 It is a structural diagram of the quality improvement unit.

[0026] Figure 3 It is a structural diagram of the coal molding processing mechanism.

[0027] Figure 4 This is a flow chart of the low-rank coal dry distillation method of the present invention.

[0028] Figure 5 This is a flow chart for the production of oil-rich coal.

[0029] Figure 6 This is a flow chart of coal molding production.

[0030] Figure 7 It is a structural schematic diagram of another preferred embodiment of the low-rank coal dry distillation system of the present invention.

[0031] The meanings of the reference numerals in the accompanying drawings are:

[0032] Quality improvement unit 1, low-temperature dehydration device 11, medium-temperature oxygen-free dry distillation device 12, cooling device 13, denitrification device 14, medium-temperature temperature regulation device 15, integrated dry distillation furnace 16, coal briquette processing mechanism 2, batching device 21, pressing and molding machine 22, drying device 23, heat exchanger 24, high-temperature oxygen-free dry distillation device 3, cold drum device 4, purification device 5. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings.

[0034] Example 1

[0035] like Figure 1 As shown, a preferred embodiment of the carbonization system for reducing coking of the present invention includes an upgrading unit 1, a briquette processing mechanism 2, a high-temperature oxygen-free carbonization device 3, a cold drum device 4, and a purification device 5. The upgrading unit 1 is used to extract moisture and remove volatiles from low-rank coal and oil-rich waste. Specifically, it dehydrates and removes volatiles from either or both of the oil sludge and oil residue and high-moisture, high-volatile coal. Volatiles are also known as raw coal gas. In this embodiment, oil residue is used as an example. The dehydrated and devolatileized coal is then fed into the briquette processing mechanism 2, which is used to press the coal into briquette according to the proportions and dry it. The high-temperature oxygen-free carbonization device 3 is used to perform high-temperature carbonization on the briquette. The cold drum device 4 is connected to the raw gas outlet of the high-temperature oxygen-free distillation device 3. The cold drum device 4 is used to remove coal tar from the raw gas produced by the upgrading unit 1 and the high-temperature oxygen-free distillation device 3. The purification device 5 is connected to the cold drum device 4. The purification device 5 is used to purify impurities in the raw gas to produce hydrogen-rich coal gas. The purification device 5 is also connected to the upgrading unit 1 and the high-temperature oxygen-free distillation device 3 via a pipeline. The hydrogen-rich coal gas is sent to the upgrading unit 1 as fuel to heat the flue gas. The hydrogen-rich coal gas is sent to the high-temperature oxygen-free distillation device 3 to be burned as fuel to generate high-temperature flue gas for dry distillation of the coal briquettes. The high-temperature oxygen-free distillation device 3, the cold drum device 4, and the purification device 5 are existing equipment, and their principles and structures are not further described here. By adding oil sludge and oil residue to low-rank coal in advance and precipitating the oil and gas in the oil residue in advance, oil-rich coal with a certain viscosity can be obtained, and the amount of binder used can be reduced during the processing of briquette, thereby saving costs. Adding oil residue in advance can increase the proportion of oil residue added, and the hardness of the processed briquette can be higher, which is 10 times the hardness of the briquette made by the original method.

[0036] like Figure 2As shown, the upgrading unit 1 includes a low-temperature dehydration device 11 and a medium-temperature oxygen-free distillation device 12. The low-temperature dehydration device 11 is used to heat the oil residue and low-rank coal. The low-temperature dehydration device 11 directly contacts the low-rank coal and oil residue through flue gas to heat them to achieve dehydration. Direct contact can reduce heat damage, thereby reducing the amount of flue gas used, and further reducing the energy required for flue gas heating. It should be known that flue gas can also be in indirect contact with low-rank coal and oil residue. The medium-temperature oxygen-free distillation device 12 is used to perform low-temperature distillation on the dehydrated low-rank coal and oil residue to precipitate the volatile matter in the low-rank coal and oil residue, that is, to discharge raw coal gas.

[0037] The medium-temperature oxygen-free retorting device 12 has a medium-temperature smoke outlet, a medium-temperature smoke inlet, and a raw gas outlet. Flue gas enters the device through the medium-temperature smoke inlet. The medium-temperature oxygen-free retorting device 12 heats the coal through indirect contact between the flue gas and low-rank coal and oil residue, thereby removing volatiles. The flue gas then heats the coal and is discharged through the medium-temperature smoke outlet. Indirect contact heating typically utilizes heat exchange devices such as heat exchange tubes. The medium-temperature oxygen-free retorting device 12 typically utilizes a furnace equipped with a heat exchanger 24. The medium-temperature oxygen-free retorting device 12 is connected to a medium-temperature temperature regulating device 15, and the briquette processing mechanism 2 is connected to the medium-temperature temperature regulating device 15. That is, the medium-temperature oxygen-free retorting device 12 and the briquette processing mechanism 2 simultaneously supply flue gas to the medium-temperature temperature regulating device 15. The medium-temperature temperature regulating device 15 is connected to the medium-temperature smoke inlet of the medium-temperature oxygen-free retorting device 12, thereby delivering flue gas that meets the requirements into the medium-temperature oxygen-free retorting device 12. The medium-temperature temperature regulating device 15 is used to adjust the temperature of the flue gas, raising the flue gas temperature to 700°C to meet the requirements of the medium-temperature oxygen-free retorting device 12. After being discharged from the medium-temperature oxygen-free retorting device 12, the flue gas passes through the medium-temperature temperature regulating device 15 and is then returned to the medium-temperature oxygen-free retorting device 12. The flue gas is recycled, reducing flue gas usage, thereby reducing energy consumption to produce the flue gas, and thus saving energy. The medium-temperature oxygen-free carbonization device 12 is connected to the cold drum device 4. Specifically, the cold drum device 4 is connected to the raw gas outlet via a pipeline. The raw gas generated by the medium-temperature oxygen-free carbonization device 12 is fed into the cold drum device 4, which is used to remove coal tar from the raw gas. The purification device 5 is also connected to the medium-temperature temperature adjustment device 15 via a pipeline, thereby providing the medium-temperature temperature adjustment device 15 with hydrogen-rich gas for use as fuel.

[0038] The low-temperature dehydration device 11 has a low-temperature smoke outlet and a low-temperature smoke inlet. The flue gas used for heating enters the device through the low-temperature smoke inlet. The flue gas heats low-rank coal and oil residue and is discharged from the low-temperature smoke outlet. The low-temperature dehydration device 11 usually adopts a furnace. The low-temperature dehydration device 11 is used to dehydrate low-rank coal and oil residue, so the flue gas discharged from the low-temperature dehydration device 11 contains a large amount of water. The low-temperature dehydration device 11 is also connected to the cooling device 13. The cooling device 13 is connected to the low-temperature dehydration device 11 by a pipeline to facilitate the introduction of flue gas into the cooling device 13. Part of the flue gas discharged by the low-temperature dehydration device 11 is sent to the cooling device 13, and the remaining excess flue gas is discharged for environmental treatment. The cooling device 13 is used to extract moisture from the flue gas. The flue gas discharged from the low-temperature dehydration device 11 is cooled by the cooling device 13, reducing its temperature. The cooling device 13 also condenses and extracts moisture from the flue gas, increasing its dryness and facilitating reuse. The cooling device 13 typically utilizes a spray device. The condensed water is cooled and then supplied to the cooling device 13 for use. Excess water can be used by other devices. The cooling device 13 is connected to a medium-temperature temperature regulating device 15, which is connected to a denitrification device 14 via a pipeline. The high-temperature flue gas heated by the medium-temperature temperature regulating device 15 is mixed with the flue gas discharged from the cooling device 13 to form 300°C flue gas, which is then fed into the denitrification device 14. The denitrification device 14 is used to denitrify the flue gas. Since flue gas denitrification requires certain temperature requirements, and the temperature of the flue gas discharged from the low-temperature dehydration device 11 does not meet the temperature requirements of the denitrification device 14, denitrification before the flue gas enters the low-temperature dehydration device 11 can effectively avoid the step of heating the flue gas discharged from the low-temperature dehydration device 11 again for denitrification, which can reduce energy consumption. At the same time, the denitrification device 14 can also evenly mix the cooled flue gas and the heated flue gas to ensure uniform flue gas temperature and prevent nitrogen oxides in the flue gas from combining with low-rank coal. The flue gas at 270°C after denitrification is sent to the low-temperature dehydration device 11 for dehydration. The medium-temperature oxygen-free distillation device 12 and the denitrification device 14 are both connected to the medium-temperature temperature adjustment device 15, which can reduce the number of equipment and reduce costs. In this way, only a small amount of high-temperature flue gas is needed to mix with the flue gas cooled by the cooling device 13 to reach the temperature required by the denitrification device 14, reducing the consumption of hydrogen-rich coal gas required for combustion in the temperature adjustment device and saving energy.

[0039] like Figure 3As shown, the briquette processing mechanism 2 includes a batching device 21 for mixing the coal discharged from the medium-temperature oxygen-free distillation device 12 with other raw materials according to a proportion to form a material, a pressing and molding machine 22 for pressing the proportioned materials into briquette, a drying device 23 for removing moisture from the briquette, and a heat exchanger 24 for providing hot air to the drying device 23. The heat exchanger 24 is connected to the high-temperature oxygen-free distillation device 3. The flue gas discharged from the high-temperature oxygen-free distillation device 3 enters the heat exchanger 24 to heat the air, and the heated hot air is sent to the drying device 23.

[0040] like Figures 4 to 6 As shown, the low-rank coal dry distillation method is as follows:

[0041] Step S1: Upgrading low-rank coal. Specifically, the process includes step S11, simultaneously adding oil residue and low-rank coal to a low-temperature dehydration device 11 to achieve a certain proportion of oil residue to the low-rank coal; step S12, dehydrating the low-rank coal and oil residue added in proportion by heating them with flue gas from the low-temperature dehydration device 11; and step S13, performing medium-temperature oxygen-free dry distillation. The dehydrated low-rank coal and oil residue are fed into the medium-temperature oxygen-free dry distillation device 12 for dry distillation to remove volatile matter from the low-rank coal and oil residue to obtain oil-rich coal.

[0042] Step S2: Forming the oil-rich coal into briquettes. Specifically, the process includes step S21: Using a batching device 21 to mix the oil-rich coal and a binder according to a specific ratio; step S22: Pressing the coal into briquettes using a press 22; and step S23: Drying the briquettes using a drying device 23 to obtain high-strength briquettes.

[0043] Step S3, high-temperature dry distillation of the coal briquettes, sending the dried coal briquettes into the high-temperature oxygen-free dry distillation device 3 for dry distillation.

[0044] Adding oil residue during the upgrading process of low-rank coal, compared to the existing method of adding oil residue during the briquette production process, allows the oil content (i.e., volatile matter) in the oil residue to be precipitated earlier during the medium-temperature oxygen-free dry distillation process, preserving its viscosity. This results in a low oil content and a certain viscosity in the upgraded oil-rich coal. This makes it less likely for oil to precipitate during the high-temperature oxygen-free dry distillation process, and thus less likely to cause coking. Furthermore, the ability to add more oil residue increases the hardness of the briquette, which is 10 times the hardness of briquette produced by the existing method. This makes it less likely to break, further reducing the likelihood of coking and eliminating the need for a decoking mechanism within the high-temperature oxygen-free dry distillation apparatus 3. Because the oil-rich coal has a certain viscosity, the amount of binder added can also be reduced, further reducing costs. Due to the larger proportion of oil residue, more coal tar byproducts can be produced compared to existing dry distillation methods, improving economic efficiency.

[0045] The flue gas discharged from the low-temperature dehydration device 11 enters the cooling device 13, and the excess flue gas is discharged through the external exhaust pipe to ensure a reasonable flue gas volume. After being cooled by the cooling device 13 to remove moisture from the flue gas, it is mixed with the flue gas sent from the medium-temperature temperature regulating device 15 and sent to the denitrification device. After denitrification, it is sent to the low-temperature dehydration device 11 for heating and dehydration, completing the flue gas cycle. The flue gas discharged from the medium-temperature oxygen-free distillation device 12 enters the medium-temperature temperature regulating device 15 to adjust the temperature. The medium-temperature temperature regulating device 15 burns the coal gas purified by the purification device 5 to increase the flue gas temperature, and then it is sent to the medium-temperature oxygen-free distillation device 12 to continue removing volatiles, completing the flue gas cycle. The flue gas generated by the high-temperature oxygen-free distillation is sent to the medium-temperature temperature regulating device 15 after heat exchange through the heat exchanger 24 to supplement the flue gas used by the medium-temperature oxygen-free distillation device 12, ensuring that the medium-temperature oxygen-free distillation device 12 has sufficient flue gas volume. Flue gas is recycled in multiple devices, which can maximize the use of flue gas heat, reduce the gas used for flue gas heating, and save energy and reduce emissions.

[0046] Example 2

[0047] like Figure 7 As shown, this embodiment differs from the first embodiment in that the upgrading unit 1 has a different structure. The upgrading unit 1 comprises an integrated retort 16 capable of dehydrating and removing volatile components, and a medium-temperature temperature control device 15 for regulating the flue gas temperature. The medium-temperature temperature control device 15 is connected to the integrated retort 16 and the heat exchanger 24 via a pipeline. The flue gas discharged from the integrated retort 16 and the flue gas after heat exchange in the heat exchanger 24 are fed into the medium-temperature temperature control device 15 to raise the flue gas temperature. After the flue gas temperature is raised, it is returned to the integrated retort 16 for use. The flue gas non-contactly retorts the oil residue and low-rank coal in the middle of the integrated retort 16, then dehydrates the oil residue and low-rank coal in the upper portion of the integrated retort 16. After dehydration, the low-rank coal and oil residue are first dehydrated and then retorted in the integrated retort 16, completing the upgrading process to produce oil-rich coal.

[0048] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention's description and drawings, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the present invention.

Claims

1. A low-rank coal dry distillation method, characterized in that: The following steps are included Step S1, upgrading low-rank coal added with oil-rich waste to form oil-rich coal; Step S2, pressing the oil-rich coal into coal briquettes; Step S3, subjecting the briquette to high-temperature dry distillation.

2. The low-rank coal dry distillation method according to claim 1, wherein: Step S1 includes the following steps: Step S11, adding oil-rich waste to low-rank coal; Step S12, performing low-temperature dehydration treatment on the low-rank coal containing oil-rich waste; In step S13, the dehydrated low-rank coal containing oil-rich waste is subjected to medium-temperature oxygen-free dry distillation to obtain oil-rich coal.

3. The low-rank coal dry distillation method according to claim 2, wherein: In step S11, the oil-rich waste and the low-rank coal are simultaneously added to a quality upgrading unit for low-temperature dehydration and medium-temperature oxygen-free dry distillation.

4. The low-rank coal dry distillation method according to claim 2, wherein: In step S12, low-temperature flue gas is used to directly or indirectly heat the low-rank coal containing oil-rich waste to dehydrate it.

5. The low-rank coal dry distillation method according to claim 2, wherein: In step S13, medium-temperature flue gas is used to indirectly heat the dehydrated low-rank coal containing oil-rich waste to perform dry distillation.

6. The low-rank coal dry distillation method according to claim 1, wherein: Step S2 includes the following steps: Step S21, mixing the oil-rich coal and the binder according to a ratio; Step S22, then using a pressing machine to press the oil-rich coal into briquettes; Step S23, drying the briquettes through a drying device.

7. A low-rank coal dry distillation system, characterized by: It includes a quality improvement unit for removing moisture and volatilization of low-rank coal added with oil-rich waste, a briquette processing mechanism for pressing the upgraded coal into briquette and drying the briquette, and a high-temperature distillation device for dry distilling the pressed coal. The quality improvement unit includes a low-temperature dehydration device for low-temperature dehydration, a cooling device for removing moisture from the flue gas discharged by the low-temperature dehydration device, a denitrification device for denitrifying the flue gas, a medium-temperature oxygen-free distillation device for medium-temperature oxygen-free distillation, and a medium-temperature temperature regulating device for raising the temperature of the flue gas. The flue gas generated by the high-temperature distillation device is sent to the briquette processing mechanism for drying the briquette. The flue gas discharged by the medium-temperature oxygen-free distillation device and the briquette processing mechanism are both sent to the medium-temperature temperature regulating device. After the medium-temperature temperature regulating device raises the temperature of the flue gas, part of it is sent to the medium-temperature oxygen-free distillation device, and the remaining part of the flue gas is sent to the denitrification device. The flue gas treated by the cooling device is sent to the denitrification device, and the denitrification device sends the denitrified flue gas to the low-temperature dehydration device.

8. The low-rank coal dry distillation system according to claim 7, characterized in that: It also includes a cold drum device for removing coal tar from raw gas and a purification device for purifying raw gas. The raw gas generated by the medium-temperature oxygen-free distillation device and the raw gas generated by the high-temperature oxygen-free distillation device are respectively sent to the corresponding cold drum devices or to the same cold drum device. The raw gas from which coal tar has been removed is sent to the purification device for purification to obtain coal gas, and part of the coal gas is sent to the medium-temperature temperature regulation device and the high-temperature oxygen-free distillation device through a pipeline.

9. A low-rank coal dry distillation system, characterized by: It includes a quality improvement unit for removing moisture and volatilization of low-rank coal added with oil-rich waste, a briquette processing mechanism for pressing the upgraded coal into shape, and a high-temperature distillation device for dry distilling the pressed coal. The quality improvement unit includes an integrated distillation furnace for first low-temperature dehydration and then medium-temperature distillation, and a medium-temperature temperature regulating device for regulating the flue gas temperature. The flue gas generated by the high-temperature distillation device is sent to the briquette processing mechanism to dry the briquette. The flue gas discharged from the integrated distillation furnace and the briquette processing mechanism is sent to the medium-temperature temperature regulating device. The medium-temperature temperature regulating device raises the flue gas temperature and then sends it to the medium-temperature oxygen-free distillation device.

10. The low-rank coal dry distillation system according to claim 9, characterized in that: It also includes a cold drum device for removing coal tar from raw gas and a purification device for purifying raw gas. The raw gas generated by the integrated retort furnace and the raw gas generated by the high-temperature oxygen-free retort device are respectively sent to the corresponding cold drum device or to the same cold drum device. The raw gas from which coal tar has been removed is sent to the purification device for purification to obtain coal gas, and part of the coal gas is sent to the medium-temperature temperature adjustment device and the high-temperature oxygen-free retort device through a pipeline.

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