Raw gas source upgrading system and method for internal heating type vertical furnace

Abstract

The invention relates to an internally heated vertical furnace raw gas source upgrading system and method. The system comprises a dry distillation furnace, a carbon dioxide removal device and a pure oxygen preparation device, the device further comprises a first multi-stage mixer, a second multi-stage mixer, a gas sampling analysis tube and a gas component detector. Pure oxygen is adopted as a combustion improver, so that the content of nitrogen in the raw gas is greatly reduced, and the application scene of coal gasification production and deep processing of the internal heating type vertical furnace is expanded; the components of combustion-supporting gas, combustible gas and inert gas in mixed gas in a lattice wall of the dry distillation furnace are controlled by adopting double-circulation control of carbon dioxide and recirculated gas, the combustion intensity and the uniformity degree are strictly controlled under the condition that dry distillation heat supply is met, and scabbing and burning loss of a dry distillation furnace body are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of low-rank coal dry distillation, and in particular to an internal heating type vertical furnace rough coal gas source quality improvement system and method. Background Art

[0002] The characteristics of low-rank coal resources are large reserves, shallow burial depth and low mining cost. The geological reserves of low-rank coal in the world are about 4 trillion tons, accounting for about 40% of the world's total coal reserves. my country's high-quality coal resources such as bituminous coal and anthracite have been fully utilized, while the large-scale development and utilization of low-rank coal has just begun.

[0003] At present, the industry mainly uses internal heating vertical furnaces to upgrade the quality of low-rank coal and realize the utilization of low-rank coal. It adopts the method of introducing a mixture of coal gas and air into the furnace, and burns the low-rank coal in the furnace to perform dry distillation. The coal gas produced is large in quantity but low in quality, and the content of invalid components such as nitrogen is greater than 50%. This low-grade coal gas can only be sent to power plants for combustion and power generation, and cannot be used for subsequent deep processing of chemical products.

[0004] Therefore, it is necessary to develop a reasonable low-rank coal distillation system and method to improve the grade of distillation coal gas, rationalize and cascade the utilization of coal resources, and meet the needs of producing high calorific value coal gas, efficiently purifying coal tar and high-quality semi-coke.

[0005] A Chinese patent application with application publication number CN111187632A discloses a "coal gas fractionation and return furnace internal heating low-temperature oxygen-enriched coal distillation process method and system". Dehydrogenated coal gas, air and oxygen are introduced into the internal heating low-temperature coal distillation furnace; the air and oxygen are mixed to form an oxygen-enriched combustion-supporting gas, and the dehydrogenated coal gas is oxygen-enriched and burned with the oxygen-enriched combustion-supporting gas in the internal heating low-temperature coal distillation furnace; however, due to the intense intensity of the oxygen-enriched combustion, uneven combustion will result.

[0006] The Chinese invention patent with the authorization announcement number CN1966612B discloses a "low-temperature coal dry distillation production process", which adopts internal combustion and internal heat heating and a large cavity design to achieve uniform distribution, uniform heating and uniform discharge, improve the output of a single furnace and product quality, and focus on improving the tar yield. At the same time, the temperature control of the dry distillation process is achieved by adjusting the dilution ratio of heated air and coal gas and the total amount of heated gas. The control is simple and easy to operate. However, the raw coal gas produced is of low grade and contains a large amount of nitrogen, which is difficult to be processed and utilized for chemical products.

[0007] The Chinese patent application with application publication number CN116515501A discloses "an electric heating retort furnace with a dry quenching device", which uses indirect electric heating, combined with a temperature measuring device and a low-temperature carrier gas cooling device for coupling control, to achieve precise control of low-rank coal dry distillation heating, and improve the quality of dry distillation solid products; a dry quenching device is set at the bottom of the dry distillation furnace to recover heat from the dry distillation solid, and the dry quenching device uses a low-temperature carrier gas as a cooling source. However, due to the use of electric heating dry distillation, the industrial production capacity cannot be expanded and the economic benefits are low. Summary of the invention

[0008] In view of the deficiencies in the above-mentioned prior art, the present invention provides a system and method for improving the quality of raw gas from the source of an internally heated vertical furnace. Pure oxygen is used as a combustion-supporting agent, which greatly reduces the nitrogen content in the raw gas and expands the application scenarios of deep processing of coal gasification in internally heated vertical furnaces. Dual-circulation control of carbon dioxide and recycled coal gas is adopted to control the combustion-supporting gas, combustible gas and inert gas components in the mixed gas in the flower wall of the retorting furnace. While satisfying the retorting heating supply, the combustion intensity and uniformity are strictly controlled to avoid scarring and burning of the retorting furnace body.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A system for improving the quality of raw coal gas from an internal heating vertical furnace, comprising a retorting furnace, a carbon dioxide removal device and a pure oxygen preparation device; the retorting furnace is provided with a feeding section, a drying section, a retorting section, a cooling section and a discharging section in order from top to bottom; the system for improving the quality of raw coal gas from an internal heating vertical furnace also comprises a multi-stage mixer 1, a multi-stage mixer 2, a gas sampling and analysis tube and a gas composition detector; a ventilation flower wall is provided inside the furnace body of the retorting section along the central axis, and a multi-stage mixer 1 and a multi-stage mixer 2 are respectively provided outside the furnace body at both ends of the ventilation flower wall, and the mixed gas outlets of the multi-stage mixer 1 and the multi-stage mixer 2 extend into the ventilation flower wall at the corresponding end; the carbon dioxide inlet of the carbon dioxide removal device is connected to the raw coal gas outlet of the retorting furnace gas collection system through a gas inlet pipeline, and a raw gas cooling net is provided on the gas inlet pipeline a gas inlet pipeline upstream of the carbon dioxide removal device is further connected to the recycled gas inlets of the multistage mixer one and the multistage mixer two through the recycled gas pipeline; the carbon dioxide removal device is provided with a purified gas outlet and a carbon dioxide outlet, wherein the carbon dioxide outlet is respectively connected to the carbon dioxide delivery pipeline and the circulating carbon dioxide pipeline, and the circulating carbon dioxide pipeline is further connected to the circulating carbon dioxide inlets of the multistage mixer one and the multistage mixer two; the pure oxygen outlet of the pure oxygen preparation device is connected to the pure oxygen inlets of the multistage mixer one and the multistage mixer two through the pure oxygen pipeline; a mixed gas sampling point is provided in the middle of the dry distillation section, the mixed gas inlet end of the gas sampling and analysis tube is located at the mixed gas sampling point, and the mixed gas outlet end of the gas sampling and analysis tube is connected to a gas composition detector arranged outside the dry distillation furnace.

[0011] The multistage mixer 1 and the multistage mixer 2 have the same structure, and are both composed of a coaxially arranged inner sleeve, a middle sleeve and an outer sleeve; wherein the inner sleeve is provided with a pure oxygen inlet, the middle sleeve is provided with a circulating carbon dioxide inlet, and the outer sleeve is provided with a return gas inlet.

[0012] The recycled coal gas pipeline is provided with a recycled coal gas regulating valve, the recycled carbon dioxide pipeline is provided with a recycled carbon dioxide regulating valve, and the pure oxygen pipeline is provided with a pure oxygen regulating valve.

[0013] The feeding section of the retort furnace is provided with a coal material sealing device; the cooling section of the retort furnace is provided with a semi-coke cooling device, and the semi-coke cooling device is provided with a coke quenching cold medium inlet; the discharging section of the retort furnace is provided with a coke pusher and a scraper; the raw gas cooling and purification device arranged on the gas inlet pipeline includes a gas cooler and an electric tar precipitator.

[0014] A method for improving the quality of raw coal gas from an internally heated vertical furnace, comprising the following steps:

[0015] 1) The raw coal enters the retort after being pre-stored in the coal charging and sealing device, and the coke discharge speed is controlled by the coke pusher at the bottom of the retort. The raw coal is dried and retorted to form semi-coke. A multi-stage mixer 1 and a multi-stage mixer 2 are relatively arranged outside the retort section of the retort. Pure oxygen, circulating carbon dioxide and recycled coal gas are mixed in the multi-stage mixer 1 and the multi-stage mixer 2 and then enter the ventilation wall in the furnace to provide heat for the retort of the raw coal; the semi-coke is cooled and discharged from the retort through a scraper;

[0016] 2) The gas collection system of the retort furnace guides the raw coal gas produced by the retort of low-rank coal out of the retort furnace, and the raw coal gas enters the gas cooler and the electric tar collector in turn to remove ash, moisture and tar. After being purified by the gas blower, the raw coal gas is divided into two paths: one path is used as the retort gas to be retorted and burned through the multi-stage mixer 1 and the multi-stage mixer 2, and the other path enters the carbon dioxide removal device; the purified coal gas with carbon dioxide removed is sent out for subsequent deep processing of coal gas or preparation of chemical products; the carbon dioxide removed from the raw coal gas is divided into two paths: one path is sent out as the carbon dioxide product, and the other path is sent back to the retort furnace as the circulating carbon dioxide of the inert gas; the pure oxygen extracted from the air by the pure oxygen preparation device is also sent to the retort furnace simultaneously;

[0017] 3) Pure oxygen, circulating carbon dioxide and recycled coal gas are divided into two paths, and enter the inner sleeve, middle sleeve and outer sleeve of the multistage mixer 1 and the multistage mixer 2 respectively, and the pure oxygen and circulating carbon dioxide are evenly mixed through the inner sleeve and the middle sleeve, and the pure oxygen, circulating carbon dioxide and recycled coal gas are evenly mixed through the middle sleeve and the outer sleeve; a mixed gas sampling point is set in the middle of the ventilation flower wall in the retorting furnace, and the mixed gas is sent to the component detector outside the furnace through the gas sampling and analysis tube to analyze the concentration of oxygen, carbon dioxide and combustible gas in the mixed gas, and the flow of various gases is controlled according to the analysis results; the pure oxygen flow is controlled by the pure oxygen regulating valve, the circulating carbon dioxide flow is controlled by the circulating carbon dioxide regulating valve, and the recycled coal gas flow is controlled by the recycled coal gas regulating valve.

[0018] The particle size of the raw coal is 6-30 mm, and the carbonization temperature is controlled at 550-850°C.

[0019] The composition of the mixed gas in the ventilation flower wall is controlled to be: 5% to 10% oxygen; 50% to 70% carbon dioxide; 1% to 2% nitrogen; 3% to 15% carbon monoxide; 3% to 15% hydrogen; and 3% to 12% methane.

[0020] The composition of the recycled coal gas is controlled as follows: 42% to 62% carbon dioxide; 1% to 2% nitrogen; 5% to 18% carbon monoxide; 5% to 18% hydrogen; and 5% to 14% methane.

[0021] The concentration of pure oxygen in the pure oxygen preparation device is controlled at 92% to 100%; the concentration of circulating carbon dioxide in the carbon dioxide removal device is controlled at 92% to 100%.

[0022] The amount of pure oxygen required for the dry distillation of the raw coal is 80-120 Nm 3 / t coal, the required circulating carbon dioxide amount is 250~330Nm 3 / t coal, the required amount of recycled coal gas is 670~730Nm 3 / t coal; the output of crude coal gas from dry distillation is 1100~1400Nm 3 / t coal; the amount of purified coal gas after decarbonation is 220~280Nm 3 / t coal; the amount of carbon dioxide delivered is 50~75Nm 3 / t coal.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) Pure oxygen is used as a combustion aid, which greatly reduces the nitrogen content in the raw gas and expands the application scenarios of deep processing of internal heating vertical furnace coal gasification;

[0025] 2) Use carbon dioxide and recycled coal gas dual circulation control to control the combustion-supporting gas, combustible gas and inert gas components in the mixed gas in the retort furnace wall. Under the condition of satisfying the retort heating, strictly control the combustion intensity and uniformity to avoid scarring and burning of the retort furnace body. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of an internally heated vertical furnace raw gas source quality improvement system described in the present invention.

[0027] In the figure: 1. Coal charging sealing device 2. Retort furnace 3. Ventilation flower wall 4. Multistage mixer 1 5. Multistage mixer 2 6. Semi-coke cooling device 7. Coke pusher 8. Scraper 9. Retort furnace gas collection system 10. Gas cooler 11. Electric tar collector 12. Gas fan 13. Carbon dioxide removal device 14. Pure oxygen preparation device 15. Pure oxygen regulating valve 16. Circulating carbon dioxide regulating valve 17. Recycled gas regulating valve 18. Gas sampling and analysis tube 19. Gas composition detector

[0028] A. Raw coalB. Mixed gas in the flower wallC. Cooling medium for quenching cokeD. Semi-cokeE. Raw coal gasF. Purified raw coal gasG. Externally sent decarbonated and purified coal gasH. Externally sent carbon dioxideI. Pure oxygenJ. Recycled carbon dioxideK. Recycled coal gas DETAILED DESCRIPTION

[0029] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0030] like Figure 1As shown, the internal heating type vertical furnace raw gas source quality improvement system of the present invention comprises a retort 2, a carbon dioxide removal device 13 and a pure oxygen preparation device 14; the retort is provided with a feeding section, a drying section, a retort, a cooling section and a discharging section in sequence from top to bottom; the internal heating type vertical furnace raw gas source quality improvement system also comprises a multi-stage mixer 4, a multi-stage mixer 5, a gas sampling and analysis tube 18 and a gas composition detector 19; a ventilation flower wall 3 is provided along the central axis in the furnace body of the retort section, and multi-stage mixers 14 and multi-stage mixers 25 are respectively provided outside the furnace body at both ends of the ventilation flower wall 3, and the mixed gas outlets of the multi-stage mixers 14 and multi-stage mixers 25 extend into the ventilation flower wall 3 at the corresponding end; the carbon dioxide inlet of the carbon dioxide removal device 13 is connected to the raw gas outlet of the retort gas collection system 9 through a gas inlet pipeline, and a A raw gas cooling and purification device and a gas blower 12; the gas inlet pipeline upstream of the carbon dioxide removal device 13 is also connected to the return gas inlet of the multistage mixer 1 4 and the multistage mixer 2 5 through the return gas pipeline; the carbon dioxide removal device 13 is provided with a purified gas outlet and a carbon dioxide outlet, wherein the carbon dioxide outlet is respectively connected to the carbon dioxide delivery pipeline and the circulating carbon dioxide pipeline, and the circulating carbon dioxide pipeline is also connected to the circulating carbon dioxide inlet of the multistage mixer 1 4 and the multistage mixer 2 5; the pure oxygen outlet of the pure oxygen preparation device 14 is connected to the pure oxygen inlet of the multistage mixer 1 4 and the multistage mixer 2 5 through the pure oxygen pipeline; a mixed gas sampling point is provided in the middle of the dry distillation section, the mixed gas inlet end of the gas sampling analysis tube 18 is located at the mixed gas sampling point, and the mixed gas outlet end of the gas sampling analysis tube is connected to a gas composition detector 19 arranged outside the dry distillation furnace.

[0031] The multistage mixer 1 4 and the multistage mixer 2 5 have the same structure, and are both composed of a coaxially arranged inner sleeve, a middle sleeve and an outer sleeve; wherein the inner sleeve is provided with a pure oxygen inlet, the middle sleeve is provided with a circulating carbon dioxide inlet, and the outer sleeve is provided with a return gas inlet.

[0032] The recycled coal gas pipeline is provided with a recycled coal gas regulating valve 17 , the recycled carbon dioxide pipeline is provided with a recycled carbon dioxide regulating valve 16 , and the pure oxygen pipeline is provided with a pure oxygen regulating valve 15 .

[0033] The feeding section of the retort furnace 2 is provided with a coal charging sealing device 1; the cooling section of the retort furnace 2 is provided with a semi-coke cooling device 6, and the semi-coke cooling device 6 is provided with a coke quenching cold medium inlet; the discharging section of the retort furnace 2 is provided with a coke pusher 7 and a scraper 8; the raw gas cooling and purification device arranged on the gas inlet pipeline includes a gas cooler 10 and an electric tar precipitator 11.

[0034] The method for improving the quality of raw coal gas from an internally heated vertical furnace according to the present invention comprises the following steps:

[0035] 1) The raw coal enters the retort after being pre-stored in the coal charging and sealing device, and the coke discharge speed is controlled by the coke pusher at the bottom of the retort. The raw coal is dried and retorted to form semi-coke. A multi-stage mixer 1 and a multi-stage mixer 2 are relatively arranged outside the retort section of the retort. Pure oxygen, circulating carbon dioxide and recycled coal gas are mixed in the multi-stage mixer 1 and the multi-stage mixer 2 and then enter the ventilation wall in the furnace to provide heat for the retort of the raw coal; the semi-coke is cooled and discharged from the retort through a scraper;

[0036] 2) The gas collection system of the retort furnace guides the raw coal gas produced by the retort of low-rank coal out of the retort furnace, and the raw coal gas enters the gas cooler and the electric tar collector in turn to remove ash, moisture and tar. After being purified by the gas blower, the raw coal gas is divided into two paths: one path is used as the retort gas to be retorted and burned through the multi-stage mixer 1 and the multi-stage mixer 2, and the other path enters the carbon dioxide removal device; the purified coal gas with carbon dioxide removed is sent out for subsequent deep processing of coal gas or preparation of chemical products; the carbon dioxide removed from the raw coal gas is divided into two paths: one path is sent out as the carbon dioxide product, and the other path is sent back to the retort furnace as the circulating carbon dioxide of the inert gas; the pure oxygen extracted from the air by the pure oxygen preparation device is also sent to the retort furnace simultaneously;

[0037] 3) Pure oxygen, circulating carbon dioxide and recycled coal gas are divided into two paths, and enter the inner sleeve, middle sleeve and outer sleeve of the multistage mixer 1 and the multistage mixer 2 respectively, and the pure oxygen and circulating carbon dioxide are evenly mixed through the inner sleeve and the middle sleeve, and the pure oxygen, circulating carbon dioxide and recycled coal gas are evenly mixed through the middle sleeve and the outer sleeve; a mixed gas sampling point is set in the middle of the ventilation flower wall in the retorting furnace, and the mixed gas is sent to the component detector outside the furnace through the gas sampling and analysis tube to analyze the concentration of oxygen, carbon dioxide and combustible gas in the mixed gas, and the flow of various gases is controlled according to the analysis results; the pure oxygen flow is controlled by the pure oxygen regulating valve, the circulating carbon dioxide flow is controlled by the circulating carbon dioxide regulating valve, and the recycled coal gas flow is controlled by the recycled coal gas regulating valve.

[0038] The particle size of the raw coal is 6-30 mm, and the carbonization temperature is controlled at 550-850°C.

[0039] The composition of the mixed gas in the ventilation flower wall is controlled to be: 5% to 10% oxygen; 50% to 70% carbon dioxide; 1% to 2% nitrogen; 3% to 15% carbon monoxide; 3% to 15% hydrogen; and 3% to 12% methane.

[0040] The composition of the recycled coal gas is controlled as follows: 42% to 62% carbon dioxide; 1% to 2% nitrogen; 5% to 18% carbon monoxide; 5% to 18% hydrogen; and 5% to 14% methane.

[0041] The concentration of pure oxygen in the pure oxygen preparation device is controlled at 92% to 100%; the concentration of circulating carbon dioxide in the carbon dioxide removal device is controlled at 92% to 100%.

[0042] The amount of pure oxygen required for the dry distillation of the raw coal is 80-120 Nm 3 / t coal, the required circulating carbon dioxide amount is 250~330Nm 3 / t coal, the required amount of recycled coal gas is 670~730Nm 3 / t coal; the output of crude coal gas from dry distillation is 1100~1400Nm 3 / t coal; the amount of purified coal gas after decarbonation is 220~280Nm 3 / t coal; the amount of carbon dioxide delivered is 50~75Nm 3 / t coal.

[0043] like Figure 1 As shown, the specific process of the method for improving the quality of raw coal gas from an internally heated vertical furnace according to the present invention is as follows:

[0044] The raw coal A enters the top of the retort 2 after being pre-stored in the coal charging and sealing device 1, and the coke discharge speed is controlled by the coke pusher 7 at the bottom of the retort 2, and passes through the drying section, the retort section and the cooling section in sequence, and finally the semi-coke D is discharged through the scraper 8. Multistage mixer 1 4 and multistage mixer 2 5 are respectively arranged on both sides of the retort section of the retort 2. Pure oxygen, circulating carbon dioxide and recycled coal gas are mixed in the two multistage mixers respectively, and then enter the ventilation wall 3 to provide heat for the retort reaction of the raw coal. The cooling section of the retort 2 is provided with a semi-coke cooling device 6, which is used to realize the coke quenching function by introducing the coke quenching cold medium C.

[0045] The gas collection system 9 of the retort furnace is connected to the raw gas outlet on the top of the retort furnace 2, and the raw gas E produced by the retort of low-rank coal is led out of the retort furnace 2. The raw gas E enters the gas cooler 10 and the electric tar collector 11 through a pipeline to remove ash, moisture and tar. The purified raw gas outlet of the electric tar collector 11 is connected to the gas blower 12 through a pipeline to pressurize the purified raw gas. The pressurized purified raw gas F is divided into two paths: one path is used as the return gas K to be returned to the furnace for combustion through the multi-stage mixer 1 4 and the multi-stage mixer 2 5, and the other path enters the carbon dioxide removal device 13 through a pipeline to obtain the outbound decarbonized purified gas G for subsequent deep processing of coal gas or preparation of chemical products.

[0046] The carbon dioxide obtained after removal is divided into two paths through pipelines: one path is the external carbon dioxide H, and the other path is the circulating carbon dioxide J, which is sent into the retort 2 as an inert gas. The pure oxygen I extracted from the air by the pure oxygen preparation device 14 is also sent into the retort 2 simultaneously.

[0047] I pure oxygen, circulating carbon dioxide J and recycled coal gas K are divided into two paths, respectively entering the inner sleeve, middle sleeve and outer sleeve of multistage mixer 1 4 and multistage mixer 2 5, and realizing uniform mixing of pure oxygen I and circulating carbon dioxide J through the inner sleeve and middle sleeve, and realizing uniform mixing of pure oxygen I, circulating carbon dioxide J and recycled coal gas K through the middle sleeve and outer sleeve. A mixed gas sampling point is set in the middle of the ventilation flower wall 3 in the retorting furnace 2, and is sent to the gas component detector 19 outside the furnace through the gas sampling analysis tube 18, and the concentration of oxygen, carbon dioxide and combustible gas in the mixed gas in the flower wall is analyzed to control the flow rate of various intake gases. The flow rates of pure oxygen I, circulating carbon dioxide J and recycled coal gas K are controlled by the corresponding pure oxygen regulating valve 15, circulating carbon dioxide regulating valve 16 and recycled coal gas regulating valve 17 respectively.

[0048] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An internal heating type vertical furnace raw gas source quality improvement system, comprising a retort furnace, a carbon dioxide removal device and a pure oxygen preparation device; the retort furnace is provided with a feeding section, a drying section, a retort section, a cooling section and a discharging section from top to bottom; characterized in that: The internal heating type vertical furnace raw gas source quality improvement system also includes a multi-stage mixer 1, a multi-stage mixer 2, a gas sampling analysis tube and a gas composition detector; a ventilation flower wall is provided inside the furnace body of the dry distillation section along the central axis, and multi-stage mixer 1 and multi-stage mixer 2 are respectively provided outside the furnace body at both ends of the ventilation flower wall, and the mixed gas outlets of the multi-stage mixer 1 and the multi-stage mixer 2 extend into the ventilation flower wall at the corresponding end; the carbon dioxide inlet of the carbon dioxide removal device is connected to the raw gas outlet of the dry distillation furnace gas collection system through a gas inlet pipeline, and a raw gas cooling and purification device and a gas blower are provided on the gas inlet pipeline; the gas inlet pipeline upstream of the carbon dioxide removal device is also connected to the furnace gas pipeline through the return gas pipeline The recycled coal gas inlet of the multistage mixer one and the multistage mixer two is connected; the carbon dioxide removal device is provided with a purified coal gas outlet and a carbon dioxide outlet, wherein the carbon dioxide outlet is respectively connected to the carbon dioxide delivery pipeline and the circulating carbon dioxide pipeline, and the circulating carbon dioxide pipeline is additionally connected to the circulating carbon dioxide inlet of the multistage mixer one and the multistage mixer two; the pure oxygen outlet of the pure oxygen preparation device is connected to the pure oxygen inlet of the multistage mixer one and the multistage mixer two through the pure oxygen pipeline; a mixed gas sampling point is provided in the middle of the dry distillation section, the mixed gas inlet end of the gas sampling analysis tube is located at the mixed gas sampling point, and the mixed gas outlet end of the gas sampling analysis tube is connected to a gas composition detector arranged outside the dry distillation furnace.

2. The internal heating type vertical furnace raw gas source upgrading system according to claim 1 is characterized in that: The multistage mixer 1 and the multistage mixer 2 have the same structure, and are both composed of a coaxially arranged inner sleeve, a middle sleeve and an outer sleeve; wherein the inner sleeve is provided with a pure oxygen inlet, the middle sleeve is provided with a circulating carbon dioxide inlet, and the outer sleeve is provided with a return gas inlet.

3. The internal heating type vertical furnace raw gas source upgrading system according to claim 1 is characterized in that: The recycled coal gas pipeline is provided with a recycled coal gas regulating valve, the recycled carbon dioxide pipeline is provided with a recycled carbon dioxide regulating valve, and the pure oxygen pipeline is provided with a pure oxygen regulating valve.

4. The internal heating type vertical furnace raw gas source upgrading system according to claim 1 is characterized in that: The feeding section of the retort furnace is provided with a coal material sealing device; the cooling section of the retort furnace is provided with a semi-coke cooling device, and the semi-coke cooling device is provided with a coke quenching cold medium inlet; the discharging section of the retort furnace is provided with a coke pusher and a scraper; the raw gas cooling and purification device arranged on the gas inlet pipeline includes a gas cooler and an electric tar precipitator.

5. A method for upgrading the raw gas source of an internally heated vertical furnace, which is implemented based on the internally heated vertical furnace raw gas source upgrading system according to any one of claims 1 to 4, characterized in that: The process includes the following: 1) The raw coal enters the retort after being pre-stored in the coal charging and sealing device, and the coke discharge speed is controlled by the coke pusher at the bottom of the retort. The raw coal is dried and retorted to form semi-coke. A multi-stage mixer 1 and a multi-stage mixer 2 are relatively arranged outside the retort section of the retort. Pure oxygen, circulating carbon dioxide and recycled coal gas are mixed in the multi-stage mixer 1 and the multi-stage mixer 2 and then enter the ventilation wall in the furnace to provide heat for the retort of the raw coal; the semi-coke is cooled and discharged from the retort through a scraper; 2) The gas collection system of the retort furnace guides the raw coal gas produced by the retort of low-rank coal out of the retort furnace, and the raw coal gas enters the gas cooler and the electric tar collector in turn to remove ash, moisture and tar. After being purified by the gas blower, the raw coal gas is divided into two paths: one path is used as the retort gas to be retorted and burned through the multi-stage mixer 1 and the multi-stage mixer 2, and the other path enters the carbon dioxide removal device; the purified coal gas with carbon dioxide removed is sent out for subsequent deep processing of coal gas or preparation of chemical products; the carbon dioxide removed from the raw coal gas is divided into two paths: one path is sent out as the carbon dioxide product, and the other path is sent back to the retort furnace as the circulating carbon dioxide of the inert gas; the pure oxygen extracted from the air by the pure oxygen preparation device is also sent to the retort furnace simultaneously; 3) Pure oxygen, circulating carbon dioxide and recycled coal gas are divided into two paths, and enter the inner sleeve, middle sleeve and outer sleeve of the multistage mixer 1 and the multistage mixer 2 respectively, and the pure oxygen and circulating carbon dioxide are evenly mixed through the inner sleeve and the middle sleeve, and the pure oxygen, circulating carbon dioxide and recycled coal gas are evenly mixed through the middle sleeve and the outer sleeve; a mixed gas sampling point is set in the middle of the ventilation flower wall in the retorting furnace, and the mixed gas is sent to the component detector outside the furnace through the gas sampling and analysis tube to analyze the concentration of oxygen, carbon dioxide and combustible gas in the mixed gas, and the flow of various gases is controlled according to the analysis results; the pure oxygen flow is controlled by the pure oxygen regulating valve, the circulating carbon dioxide flow is controlled by the circulating carbon dioxide regulating valve, and the recycled coal gas flow is controlled by the recycled coal gas regulating valve.

6. The method for upgrading the raw gas source of an internally heated vertical furnace according to claim 5, characterized in that: The particle size of the raw coal is 6-30 mm, and the carbonization temperature is controlled at 550-850°C.

7. The method for upgrading the raw gas source of an internally heated vertical furnace according to claim 5, characterized in that: The composition of the mixed gas in the ventilation flower wall is controlled to be: 5% to 10% oxygen; 50% to 70% carbon dioxide; 1% to 2% nitrogen; 3% to 15% carbon monoxide; 3% to 15% hydrogen; and 3% to 12% methane.

8. The method for upgrading the raw gas source of an internally heated vertical furnace according to claim 5, characterized in that: The composition of the recycled coal gas is controlled as follows: 42% to 62% carbon dioxide; 1% to 2% nitrogen; 5% to 18% carbon monoxide; 5% to 18% hydrogen; and 5% to 14% methane.

9. The method for upgrading the raw gas source of an internally heated vertical furnace according to claim 5, characterized in that: The concentration of pure oxygen in the pure oxygen preparation device is controlled at 92% to 100%; the concentration of circulating carbon dioxide in the carbon dioxide removal device is controlled at 92% to 100%.

10. The method for upgrading the raw gas source of an internally heated vertical furnace according to claim 5, characterized in that: The amount of pure oxygen required for the dry distillation of the raw coal is 80-120 Nm 3 / t coal, the required circulating carbon dioxide amount is 250~330Nm 3 / t coal, the required amount of recycled coal gas is 670~730Nm 3 / t coal; the output of crude coal gas from dry distillation is 1100~1400Nm 3 / t coal; the amount of purified coal gas after decarbonation is 220~280Nm 3 / t coal; the amount of carbon dioxide delivered is 50~75Nm 3 / t coal.

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