A blue carbon production system and method for reducing carbon emissions

Abstract

The invention discloses a blue charcoal production system for reducing carbon emissions, and also discloses a blue charcoal production method for reducing carbon emissions. The advantages are: the effective gas components in the coal gas can be greatly improved, thereby improving the quality of the coal gas, making it meet the process standards of chemical raw gas, and improving its economic value; the reaction temperature in the coking furnace can be controlled within a certain range, and a blue charcoal product without coke can be obtained, which can be used in industries such as ferroalloys, calcium carbide, and synthetic ammonia, and most of the volatiles can be volatilized to increase the gas production of the coal gas; by adding CO2, the combustion parts of the coking furnace and the gas turbine can be protected to avoid damage to the combustion parts caused by too high reaction temperature; the nitrogen oxide content in the flue gas generated by the gas turbine can be used to prepare food-grade liquid carbon dioxide or be sent to the calcium carbide position for production as an inert gas protection gas; there is no need to discharge CO2, so the purpose of reducing carbon emissions is achieved, which is in line with the green and low-carbon production concept.

Description

Technical field:

[0001] The present invention relates to the field of coal chemical industry, and in particular to a system and method for producing semi-coke for reducing carbon emissions. Background technology:

[0002] In the past, metallurgical coke was used in the ferroalloy, calcium carbide, synthetic ammonia and other industries. However, there were problems such as high coke prices and the performance of metallurgical coke could not meet the process requirements of these industries. my country's Yulin area in Shaanxi Province has rich coal resources, and the coal types are mainly Jurassic coal, which is mainly long flame coal and non-sticky coal. Its product structure is single, and the content of coking coal and fat coal is relatively low. Therefore, the use of Jurassic coal to produce lignite has obvious advantages. Since the performance of lignite can fully meet the process requirements of ferroalloy, calcium carbide, synthetic ammonia and other industries, and the price of lignite is low, using lignite to replace metallurgical coke in ferroalloy, calcium carbide, synthetic ammonia and other industries can fully and effectively utilize local coal resources.

[0003] In the traditional semi-coke production process, air is used as the combustion-supporting gas, and the reaction temperature is controlled at about 750°C, so that excess lump coal reacts with oxygen to obtain semi-coke and coal gas. The main components and contents of the obtained coal gas are: H2: about 28%, CH4: about 8.8%, CO: about 12%, CO2: about 5%, N2: 45% to 48%. Since the combustion-supporting gas is air, which has a high nitrogen content, the nitrogen content in the obtained coal gas is as high as 45% to 48%, resulting in a low content of effective gas components in the coal gas and a low calorific value, which is usually only 1700 to 2000 kcal / Nm 3 , and cannot meet the process standards of chemical raw gas for processes such as synthetic ammonia and carbon-products. If coal gas with a high nitrogen content is to be used as chemical raw gas for processes such as synthetic ammonia and carbon-products, it needs to go through a series of process treatments such as pressurization and separation to separate the nitrogen before it can be sent to subsequent processes such as synthetic ammonia. Operations such as pressurization consume a lot of energy, resulting in high energy consumption in subsequent processing. Therefore, the coal gas can only be used as fuel gas for equipment such as gas turbines, which greatly reduces the utilization value and economic value of the coal gas and seriously affects the economic benefits of the enterprise. At the same time, the CO2 obtained after the coal gas is burned as fuel gas in the gas turbine is usually directly discharged into the air after simple flue gas treatment. The waste heat carried is not effectively recovered and utilized. Moreover, a large amount of CO2 will be emitted, which is not conducive to energy conservation and emission reduction and does not conform to the green and low-carbon production concept. Summary of the invention:

[0004] In order to solve the above problems, the first object of the present invention is to provide a blue charcoal production system for reducing carbon emissions;

[0005] The second object of the present invention is to provide a method for producing blue charcoal with reduced carbon emissions.

[0006] The first object of the present invention is implemented by the following technical solutions:

[0007] A blue coke production system for reducing carbon emissions, comprising a combustion-supporting gas preparation unit and a coking furnace;

[0008] The combustion-supporting gas preparation unit comprises a liquid oxygen storage tank, a vaporizer, a buffer tank and a CO2 pipeline; the liquid outlet of the liquid oxygen storage tank is connected to the liquid inlet of the vaporizer through a pipeline, and the gas outlet of the vaporizer and the gas outlet end of the CO2 pipeline are both connected to the inlet of the buffer tank through a pipeline; the outlet of the buffer tank is divided into two routes, one of which is connected to the combustion-supporting gas inlet of the coking furnace through a pipeline.

[0009] Furthermore, it also includes a gas purification unit and a power generation unit;

[0010] The other outlet of the buffer tank is connected to the combustion gas inlet of the gas turbine of the power generation unit through a pipeline; the raw gas outlet of the coking furnace is connected to the air inlet of the water washing tower of the gas purification unit through a pipeline; the gas outlet of the desulfurization tower of the gas purification unit is divided into two routes, one of which is connected to the fuel gas inlet of the gas turbine through a pipeline; the flue gas outlet of the waste heat boiler turbine of the power generation unit is divided into two routes, one of which is connected to the air inlet end of the CO2 pipeline.

[0011] Furthermore, another route of the gas outlet of the desulfurization tower is connected to the gas inlet of the chemical raw material gas storage tank through a pipeline.

[0012] Furthermore, another route of the flue gas outlet of the waste heat boiler turbine is connected to the air inlet of the CO2 storage tank through a pipeline.

[0013] Furthermore, the coal gas purification unit includes a water washing tower, a detarring tower and a desulfurization tower which are connected in sequence.

[0014] Further, the power generation unit includes a gas turbine and a waste heat boiler turbine;

[0015] The flue gas outlet of the gas turbine is connected to the flue gas inlet of the waste heat boiler turbine through a pipeline.

[0016] Furthermore, an O2 flow meter and an O2 flow regulating valve are provided on the pipeline connecting the gasifier and the buffer tank; a CO2 flow meter and a CO2 flow regulating valve are provided on the CO2 pipeline; and an O2 concentration sensor is provided at the outlet of the buffer tank;

[0017] The signal output ends of the O2 flowmeter, the CO2 flowmeter and the O2 concentration sensor are all signal-connected to the signal input ends of the controller, and the signal output end of the controller is signal-connected to the signal input ends of the O2 flow regulating valve and the CO2 flow regulating valve, respectively.

[0018] Furthermore, an O2 temperature sensor and an O2 pressure sensor are provided on the pipeline connecting the gasifier and the buffer tank; a CO2 temperature sensor and a CO2 pressure sensor are provided on the CO2 pipeline; and an auxiliary gas temperature sensor and an auxiliary gas pressure sensor are provided at the outlet of the buffer tank;

[0019] The signal output ends of the O2 temperature sensor, the O2 pressure sensor, the CO2 temperature sensor, the CO2 pressure sensor, the combustion-supporting gas temperature sensor and the combustion-supporting gas pressure sensor are all signal-connected to the signal input end of the controller.

[0020] The second object of the present invention is implemented by the following technical solutions:

[0021] A method for producing blue charcoal with reduced carbon emissions comprises the following steps:

[0022] (1) Preparation of combustion-supporting gas: The liquid oxygen in the liquid oxygen storage tank is vaporized by a vaporizer and then mixed with CO2 in a buffer tank to obtain a combustion-supporting gas with an oxygen volume content of 20% to 30%;

[0023] (2) Coking: a portion of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) is fed into a coking furnace, and oxygen reacts with excess lump coal to produce CO and release a large amount of heat; at the same time, CO2 reacts with excess lump coal to produce CO; and most of the volatile matter in the lump coal is volatilized under high temperature; finally, raw coal gas with CO as the main component and a semi-coke product with a volatile matter content of 3% to 5% are obtained;

[0024] Furthermore, it also includes the following steps:

[0025] (3) Coal gas purification: the raw coal gas obtained in the coking process of step (2) is first sent to a water washing tower to remove particulate matter contained therein, then sent to a detarring tower to remove substances such as phenol and naphthalene therein, and then sent to a desulfurization tower to remove sulfur contained therein, thereby obtaining pure coal gas;

[0026] (4) Power generation: another part of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) and a part of the coal gas obtained in the coal gas purification in step (3) are sent to a gas turbine to generate electricity through combustion. The high-temperature flue gas generated by the combustion enters the waste heat boiler turbine. The high-temperature flue gas first undergoes heat exchange to generate steam, and the steam then generates electricity. A part of the low-temperature flue gas with a CO2 content of more than 90% discharged after the high-temperature flue gas is cooled by the waste heat boiler turbine is sent as a dilution gas to the buffer tank in the preparation of the combustion-supporting gas in step (1) to be mixed with pure oxygen.

[0027] Advantages of the present invention:

[0028] The present invention uses a dilution gas with a carbon dioxide content of more than 90% and oxygen to mix to obtain a combustion-supporting gas with an oxygen content of 20% to 30%, and uses the combustion-supporting gas to replace air to provide combustion-supporting gas for a gas turbine and a coking furnace:

[0029] (1) The CO2 content in the flue gas generated by the gas turbine is more than 90%. On the one hand, it can be used as a dilution gas for circulation in the system. On the other hand, since the N2 content in the combustion-supporting gas is greatly reduced, the nitrogen oxide content in the flue gas generated by the gas turbine is also greatly reduced. The flue gas can be used as an inert gas protection gas for preparing food-grade liquid carbon dioxide or sent to the calcium carbide station for production. During the operation of the entire system, no CO2 will be emitted to the outside, achieving the purpose of carbon reduction and emission reduction, which is in line with the green and low-carbon production concept;

[0030] (2) The high-temperature flue gas generated by the gas turbine enters the waste heat boiler turbine. The high-temperature flue gas first undergoes heat exchange to generate steam, which then generates power, making full use of the waste heat of the flue gas and improving the utilization rate of thermal energy.

[0031] (3) A combustion-supporting gas with an oxygen content of 20% to 30% is introduced into the coking furnace, and the temperature in the coking furnace is controlled at 900°C to 1200°C. Within this temperature range, most of the CO2 in the combustion-supporting gas undergoes a reduction reaction with excess lump coal and is converted into CO, and the conversion rate is greater than 75%, thereby increasing the CO content in the raw coal gas, thereby increasing the output and quality of the raw coal gas; at this temperature, most of the volatile matter in the lump coal is volatilized, further increasing the output of the raw coal gas;

[0032] Part of the raw gas obtained after being purified by the water scrubber, detarring tower and desulfurization tower is recycled into the system as fuel for the gas turbine, and the remaining majority of the gas is used as chemical raw material gas for processes such as synthetic ammonia and carbon-products, thereby increasing its economic value. At the same time, since the N2 content in the gas is greatly reduced, it does not need to go through a series of process treatments such as pressurization and separation, which greatly reduces the energy consumption and equipment investment cost of the purification process.

[0033] At the same time, a semi-coke product with a volatile matter content of 3% to 5% is obtained, which can ensure that the particle size of the semi-coke product is mainly concentrated between 3mm and 50mm. It can replace coke in ferroalloy, calcium carbide, synthetic ammonia and other industries, greatly reducing the production costs of ferroalloy, calcium carbide, synthetic ammonia and other industries;

[0034] (4) In addition, by adding CO2, the oxygen content of the combustion-supporting gas is controlled at 20% to 30%, thereby preventing the reaction temperature from being too high and causing damage to the combustion parts, thereby protecting the combustion parts of the coking furnace and gas turbine. Description of the drawings:

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is a schematic diagram of system connection in Example 1;

[0037] Figure 2 This is a schematic diagram of system connection in Example 3;

[0038] Figure 3 It is the control principle diagram of Example 1 and Example 3.

[0039] In the figure: combustion gas preparation unit 1, liquid oxygen storage tank 11, gasifier 12, buffer tank 13, O2 temperature sensor 14, O2 pressure sensor 15, O2 flowmeter 16, O2 flow regulating valve 17, CO2 temperature sensor 18, CO2 pressure sensor 19, CO2 flowmeter 110, CO2 flow regulating valve 111, O2 concentration sensor 112, combustion gas temperature sensor 113, combustion gas pressure sensor 114, controller 115, CO2 pipeline 116, coking furnace 2, coal gas purification unit 3, water washing tower 31, detarring tower 32, desulfurization tower 33, power generation unit 4, gas turbine 41, waste heat boiler turbine 42, chemical raw gas storage tank 5, CO2 storage tank 6. Specific implementation method:

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1:

[0042] like Figure 1 , Figure 3 A blue coke production system for reducing carbon emissions is shown, comprising a combustion gas preparation unit 1 and a coking furnace 2;

[0043] The combustion gas preparation unit 1 includes a liquid oxygen storage tank 11, a vaporizer 12, a buffer tank 13 and a CO2 pipeline 116;

[0044] The liquid outlet of the liquid oxygen storage tank 11 is connected to the liquid inlet of the gasifier 12 through a pipeline, and the gas outlet of the gasifier 12 and the gas outlet end of the CO2 pipeline 116 are both connected to the inlet of the buffer tank 13 through a pipeline. The outlet of the buffer tank 13 is divided into two paths, one of which is connected to the combustion gas inlet of the coking furnace 2 through a pipeline;

[0045] An O2 flow meter 16 and an O2 flow regulating valve 17 are provided on the pipeline connecting the gasifier 12 and the buffer tank 13; a CO2 flow meter 110 and a CO2 flow regulating valve 111 are provided on the CO2 pipeline 116; an O2 concentration sensor 112 is provided at the outlet of the buffer tank 13; an O2 temperature sensor 14 and an O2 pressure sensor 15 are also provided on the pipeline connecting the gasifier 12 and the buffer tank 13; a CO2 temperature sensor 18 and a CO2 pressure sensor 19 are also provided on the CO2 pipeline 116; and an auxiliary gas temperature sensor 113 and an auxiliary gas pressure sensor 114 are also provided at the outlet of the buffer tank 13;

[0046] The signal output ends of the O2 flowmeter 16, the CO2 flowmeter 110, the O2 concentration sensor 112, the O2 temperature sensor 14, the O2 pressure sensor 15, the CO2 temperature sensor 18, the CO2 pressure sensor 19, the supporting combustion gas temperature sensor 113 and the supporting combustion gas pressure sensor 114 are all signal-connected to the signal input ends of the controller 115, and the signal output end of the controller 115 is signal-connected to the signal input ends of the O2 flow regulating valve 17 and the CO2 flow regulating valve 111, respectively.

[0047] Job Description:

[0048] CO2 is mixed with pure oxygen to obtain a combustion-supporting gas having an oxygen volume content of 20% to 30%, which provides combustion-supporting gas for the coking furnace 2;

[0049] The combustion-supporting gas enters the coking furnace 2, and undergoes combustion and gasification reaction with the lump coal in the coking furnace 2, and releases a large amount of heat; by adding CO2 to pure oxygen, the reaction temperature in the coking furnace 2 can be controlled at 900°C to 1200°C. At this time, exothermic reaction, carbon reduction reaction and dry distillation reaction occur in the coking furnace 2. The specific reaction process is as follows:

[0050] ⑴ Exothermic reaction

[0051] C 过量 +O2→CO+Q 热量

[0052] ⑵Carbon reduction reaction

[0053] CO2+C→CO-Q 热量

[0054] ⑶ Dry distillation reaction

[0055] When the lump coal is at high temperature, most of the volatile matter contained in it is volatilized, and finally a semi-coke product with a volatile matter content of 3% to 5% is obtained, and at the same time, raw coal gas is obtained. The combustible components in raw coal gas are mainly H2, CO, and CH4, and its main composition and content are: H2: 12% to 15%, CH4: about 7%, CO: 54% to 57%, CO2: 6% to 8%, N2: 6% to 8%. Most of the CO2 in the combustion-supporting gas is converted into CO through carbon reduction reaction, and the conversion rate is greater than 75%.

[0056] As the N2 content in the gas is greatly reduced, the effective gas content is greatly increased, and its calorific value can reach 3500-3800 kcal / Nm 3 , which meets the process standards of chemical raw gas for processes such as synthetic ammonia and carbon-products, and improves its economic value.

[0057] In this embodiment, the oxygen content in the combustion-supporting gas at the outlet of the buffer tank 13 can be measured by the O2 concentration sensor 112, and the opening size of the O2 flow regulating valve 17 and the CO2 flow regulating valve 111 can be adjusted to ensure that the oxygen content in the combustion-supporting gas obtained after mixing in the buffer tank 13 is maintained at 20% to 30%. At the same time, the real-time O2 flow and CO2 flow can be detected by the O2 flow meter 16 and the CO2 flow meter 110. In addition, according to the gas state equation, when the amount of gas substance is constant, the pressure, volume and temperature of the gas are interrelated. Therefore, in this embodiment, the O2 temperature sensor 14, the O2 pressure sensor 15, the CO2 temperature sensor 18, the CO2 pressure sensor 19, the combustion-supporting gas temperature sensor 113 and the combustion-supporting gas pressure sensor 114 can be used to detect the O2 temperature, O2 pressure, CO2 temperature, CO2 pressure, combustion-supporting gas temperature and combustion-supporting gas pressure, respectively, so as to play an auxiliary reference role in the adjustment of the gas volume. When the system is operating normally and stably, the O2 temperature, CO2 temperature, and combustion-supporting gas temperature are all maintained at 0℃~30℃, and the O2 pressure, CO2 pressure, and combustion-supporting gas pressure are all maintained at 5Kpa~10Kpa.

[0058] Embodiment 2:

[0059] A method for producing blue carbon by a blue carbon production system for reducing carbon emissions provided in Example 1 comprises the following steps:

[0060] (1) Preparation of combustion-supporting gas: The liquid oxygen in the liquid oxygen storage tank 11 is vaporized by the vaporizer 12 and then mixed with CO2 in the buffer tank 13 to obtain a combustion-supporting gas having an oxygen volume content of 20% to 30%, and the obtained combustion-supporting gas has a temperature of 0°C to 30°C and a pressure of 5Kpa to 10Kpa;

[0061] (2) Coking: A portion of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) is fed into the coking furnace 2, and the reaction temperature in the coking furnace 2 is controlled at 900°C to 1200°C. Oxygen reacts with excess lump coal to obtain CO and release a large amount of heat; at the same time, CO2 reacts with excess lump coal to generate CO, thereby increasing the CO content in the coal gas; and, under high temperature, most of the volatile matter in the lump coal is volatilized; finally, raw coal gas with CO as the main component and a semi-coke product with a volatile matter content of 3% to 5% are obtained, which can ensure that the particle size of the semi-coke product is mainly concentrated between 3mm and 50mm, and can be used in ferroalloy, calcium carbide, synthetic ammonia and other industries; it can avoid the situation that the semi-coke product cannot be used in ferroalloy, calcium carbide, synthetic ammonia and other industries due to the low volatile matter content in the semi-coke product, which makes the particle size too small (when most of the particle sizes are less than 3mm, the semi-coke product obtained is coke powder).

[0062] Embodiment 3:

[0063] like Figure 2 , Figure 3 A blue coke production system for reducing carbon emissions is shown, comprising a combustion gas preparation unit 1, a coking furnace 2, a coal gas purification unit 3 and a power generation unit 4;

[0064] The combustion-supporting gas preparation unit 1 includes a liquid oxygen storage tank 11, a gasifier 12, a buffer tank 13 and a CO2 pipeline 116; the coal gas purification unit 3 includes a water washing tower 31, a detarring tower 32 and a desulfurization tower 33 connected in sequence; the power generation unit 4 includes a gas turbine 41 and a waste heat boiler turbine 42.

[0065] The liquid outlet of the liquid oxygen storage tank 11 is connected to the liquid inlet of the gasifier 12 through a pipeline, and the gas outlet of the gasifier 12 and the gas outlet end of the CO2 pipeline 116 are both connected to the inlet of the buffer tank 13 through a pipeline. The outlet of the buffer tank 13 is divided into two routes, one of which is connected to the combustion-supporting gas inlet of the coking furnace 2 through a pipeline, and the other is connected to the combustion-supporting gas inlet of the gas turbine 41 through a pipeline; the raw coal gas outlet of the coking furnace 2 is connected to the air inlet of the water washing tower 31 through a pipeline; the gas outlet of the desulfurization tower 33 is divided into two routes, one of which is connected to the fuel gas inlet of the gas turbine 41 through a pipeline, and the other is connected to the air inlet of the chemical raw material gas storage tank 5 through a pipeline; the flue gas outlet of the gas turbine 41 is connected to the flue gas inlet of the waste heat boiler turbine 42, and the flue gas outlet of the waste heat boiler turbine 42 is divided into two routes, one of which is connected to the air inlet end of the CO2 pipeline 116, and the other is connected to the air inlet of the CO2 storage tank 6 through a pipeline.

[0066] An O2 flow meter 16 and an O2 flow regulating valve 17 are provided on the pipeline connecting the gasifier 12 and the buffer tank 13; a CO2 flow meter 110 and a CO2 flow regulating valve 111 are provided on the CO2 pipeline 116; an O2 concentration sensor 112 is provided at the outlet of the buffer tank 13; an O2 temperature sensor 14 and an O2 pressure sensor 15 are also provided on the pipeline connecting the gasifier 12 and the buffer tank 13; a CO2 temperature sensor 18 and a CO2 pressure sensor 19 are also provided on the CO2 pipeline 116; and an auxiliary gas temperature sensor 113 and an auxiliary gas pressure sensor 114 are also provided at the outlet of the buffer tank 13;

[0067] The signal output ends of the O2 flowmeter 16, the CO2 flowmeter 110, the O2 concentration sensor 112, the O2 temperature sensor 14, the O2 pressure sensor 15, the CO2 temperature sensor 18, the CO2 pressure sensor 19, the supporting combustion gas temperature sensor 113 and the supporting combustion gas pressure sensor 114 are all signal-connected to the signal input ends of the controller 115, and the signal output end of the controller 115 is signal-connected to the signal input ends of the O2 flow regulating valve 17 and the CO2 flow regulating valve 111, respectively.

[0068] Job Description:

[0069] The low-temperature flue gas discharged from the waste heat boiler turbine 42 is a clean gas with a CO2 content of more than 90%. It returns to the combustion-supporting gas preparation unit 1 and is mixed with pure oxygen to obtain a combustion-supporting gas with an oxygen volume content of 20% to 30%. The combustion-supporting gas provides combustion-supporting gas for the coking furnace 2 and the gas turbine 41 respectively.

[0070] The combustion-supporting gas enters the coking furnace 2, and undergoes combustion and gasification reaction with the lump coal in the coking furnace 2, and releases a large amount of heat; by adding CO2 to pure oxygen, the reaction temperature in the coking furnace 2 can be controlled at 900°C to 1200°C. At this time, exothermic reaction, carbon reduction reaction and dry distillation reaction occur in the coking furnace 2. The specific reaction process is as follows:

[0071] (1) Exothermic reaction

[0072] C 过量 +O2→CO+Q 热量

[0073] (2) Carbon reduction reaction

[0074] CO2+C→CO-Q 热量

[0075] (3) Drying reaction

[0076] Under high temperature, most of the volatile matter contained in the lump coal is volatilized, and finally a semi-coke product with a volatile matter content of 3% to 5% is obtained, and raw coal gas is obtained at the same time. The combustible components in raw coal gas are mainly H2, CO, and CH4, and its main composition and content are: H2: 12% to 15%, CH4: about 7%, CO: 54% to 57%, CO2: 6% to 8%, N2: 6% to 8%. Most of the CO2 in the combustion-supporting gas is converted into CO through carbon reduction reaction, and the conversion rate is greater than 75%.

[0077] The raw gas first enters the water washing tower 31 to remove the particulate matter contained therein, then passes through the detarring tower 32 to remove a small amount of phenol, naphthalene and other substances contained therein, and then passes through the desulfurization tower 33 to remove a small amount of S contained therein, thus obtaining a relatively pure coal gas; since the N2 content in the coal gas is greatly reduced, the effective gas component content is greatly increased, and its calorific value can reach 3500-3800 kcal / Nm 3 , which complies with the process standards of chemical raw gas for processes such as synthetic ammonia and carbon-products, so the coal gas is mainly sent to the chemical raw gas storage tank 5 and used as the chemical raw gas for the synthetic ammonia unit and other carbon-product processes to improve its economic value; at the same time, in order to ensure that the carbon in the system of this embodiment reaches a balanced state, a part of the coal gas will be sent to the gas turbine 41 as fuel gas, and it will generate electricity through combustion. The high-temperature flue gas generated by the combustion will enter the waste heat boiler turbine 42, and the high-temperature flue gas will first generate steam after heat exchange, and the steam will generate electricity; the high-temperature flue gas will be discharged after being cooled by the waste heat boiler turbine 42 Low-temperature flue gas, since the N2 content in the coal gas is greatly reduced, the nitrogen oxide content in the low-temperature flue gas is also greatly reduced, so the CO2 content in the low-temperature flue gas is more than 90%. In order to make the carbon in the system reach a balanced state, a part of the low-temperature flue gas returns to the combustion-supporting gas preparation unit 1 to prepare the combustion-supporting gas; the remaining low-temperature flue gas is sent to the CO2 storage tank 6, which can be used to prepare food-grade liquid carbon dioxide or sent to the calcium carbide station as an inert gas protective gas for production; in this way, this embodiment will not emit CO2 to the outside, achieving the purpose of carbon reduction and emission reduction, and complying with the green and low-carbon production concept.

[0078] In this embodiment, the oxygen content in the combustion-supporting gas at the outlet of the buffer tank 13 can be measured by the O2 concentration sensor 112, and the opening size of the O2 flow regulating valve 17 and the CO2 flow regulating valve 111 can be adjusted to ensure that the oxygen content in the combustion-supporting gas obtained after mixing in the buffer tank 13 is maintained at 20% to 30%. At the same time, the real-time O2 flow and CO2 flow can be detected by the O2 flow meter 16 and the CO2 flow meter 110. In addition, according to the gas state equation, when the amount of gas substance is constant, the pressure, volume and temperature of the gas are interrelated. Therefore, in this embodiment, the O2 temperature sensor 14, the O2 pressure sensor 15, the CO2 temperature sensor 18, the CO2 pressure sensor 19, the combustion-supporting gas temperature sensor 113 and the combustion-supporting gas pressure sensor 114 can be used to detect the O2 temperature, O2 pressure, CO2 temperature, CO2 pressure, combustion-supporting gas temperature and combustion-supporting gas pressure, respectively, so as to play an auxiliary reference role in the adjustment of the gas volume. When the system is operating normally and stably, the O2 temperature, CO2 temperature, and combustion-supporting gas temperature are all maintained at 0℃~30℃, and the O2 pressure, CO2 pressure, and combustion-supporting gas pressure are all maintained at 5Kpa~10Kpa.

[0079] In this embodiment, at the initial stage of system startup, some CO2 needs to be introduced from the outside into the buffer tank 13 to be mixed with pure oxygen. When the system is operating normally, only the low-temperature flue gas discharged from the waste heat boiler turbine 42 enters the buffer tank 13 to be mixed with pure oxygen, and there is no need to introduce some CO2 from the outside.

[0080] Embodiment 4:

[0081] A method for producing blue carbon by a blue carbon production system for reducing carbon emissions provided in Example 3 comprises the following steps:

[0082] (1) Preparation of combustion-supporting gas: The liquid oxygen in the liquid oxygen storage tank 11 is vaporized by the vaporizer 12 and then mixed with CO2 in the buffer tank 13 to obtain a combustion-supporting gas having an oxygen volume content of 20% to 30%, and the obtained combustion-supporting gas has a temperature of 0°C to 30°C and a pressure of 5Kpa to 10Kpa;

[0083] (2) Coking: A portion of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) is fed into the coking furnace 2, and the reaction temperature in the coking furnace 2 is controlled at 900°C to 1200°C. Oxygen reacts with excess lump coal to obtain CO and release a large amount of heat; at the same time, CO2 reacts with excess lump coal to generate CO, thereby increasing the CO content in the coal gas; and, under high temperature, most of the volatile matter in the lump coal is volatilized; finally, raw coal gas with CO as the main component and a semi-coke product with a volatile matter content of 3% to 5% are obtained, which can ensure that the particle size of the semi-coke product is mainly concentrated between 3mm and 50mm, and can be used in ferroalloy, calcium carbide, synthetic ammonia and other industries; it can avoid the situation that the semi-coke product cannot be used in ferroalloy, calcium carbide, synthetic ammonia and other industries due to the low volatile matter content in the semi-coke product, which makes the particle size too small (when most of the particle sizes are less than 3mm, the semi-coke product obtained is coke powder).

[0084] (3) Coal gas purification: The raw coal gas obtained in step (2) of coking is first sent to a water washing tower 31 to remove particulate matter contained therein, then sent to a detarring tower 32 to remove substances such as phenol and naphthalene therein, and then sent to a desulfurization tower 33 to remove sulfur contained therein, thus obtaining pure coal gas;

[0085] (4) Power generation: another part of the combustion-supporting gas obtained in step (1) of preparing the combustion-supporting gas and a part of the coal gas obtained in step (3) of purifying the coal gas are sent to the gas turbine 41 to generate power through combustion. The high-temperature flue gas generated by the combustion enters the waste heat boiler turbine 42. The high-temperature flue gas first undergoes heat exchange to generate steam, which then generates power; a part of the low-temperature flue gas with a CO2 content of more than 90% discharged after the high-temperature flue gas is cooled by the waste heat boiler turbine 42 is sent as dilution gas to the buffer tank 13 in step (1) of preparing the combustion-supporting gas to be mixed with pure oxygen. In this way, the carbon balance can be ensured without the need to discharge CO2.

[0086] In this embodiment, at the initial stage of system startup, some CO2 needs to be introduced from the outside into the buffer tank 13 to be mixed with pure oxygen. When the system is operating normally, only the low-temperature flue gas discharged from the waste heat boiler turbine 42 enters the buffer tank 13 to be mixed with pure oxygen, and there is no need to introduce some CO2 from the outside.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A blue charcoal production system for reducing carbon emissions, characterized in that: It includes a combustion gas preparation unit and a coking furnace; The combustion-supporting gas preparation unit comprises a liquid oxygen storage tank, a vaporizer, a buffer tank and a CO2 pipeline; the liquid outlet of the liquid oxygen storage tank is connected to the liquid inlet of the vaporizer through a pipeline, and the gas outlet of the vaporizer and the gas outlet end of the CO2 pipeline are both connected to the inlet of the buffer tank through a pipeline; the outlet of the buffer tank is divided into two paths, one of which is connected to the combustion-supporting gas inlet of the coking furnace through a pipeline; It also includes a gas purification unit and a power generation unit; the gas purification unit includes a water washing tower, a detarring tower and a desulfurization tower connected in sequence; the power generation unit includes a gas turbine and a waste heat boiler turbine; The other outlet of the buffer tank is connected to the combustion-supporting gas inlet of the gas turbine through a pipeline; the raw coal gas outlet of the coking furnace is connected to the air inlet of the water scrubber through a pipeline; the air outlet of the desulfurization tower is divided into two routes, one of which is connected to the fuel gas inlet of the gas turbine through a pipeline, and the flue gas outlet of the gas turbine is connected to the flue gas inlet of the waste heat boiler steam turbine through a pipeline; the flue gas outlet of the waste heat boiler steam turbine is divided into two routes, one of which is connected to the air inlet end of the CO2 pipeline, and the other of the flue gas outlet of the waste heat boiler steam turbine is connected to the air inlet of the CO2 storage tank through a pipeline; Another route of the gas outlet of the desulfurization tower is connected to the gas inlet of the chemical raw material gas storage tank through a pipeline; An O2 flow meter and an O2 flow regulating valve are provided on the pipeline connecting the gasifier and the buffer tank; a CO2 flow meter and a CO2 flow regulating valve are provided on the CO2 pipeline; and an O2 concentration sensor is provided at the outlet of the buffer tank; The signal output ends of the O2 flowmeter, the CO2 flowmeter and the O2 concentration sensor are all signal-connected to the signal input ends of the controller, and the signal output end of the controller is signal-connected to the signal input ends of the O2 flow regulating valve and the CO2 flow regulating valve, respectively.

2. A blue charcoal production system for reducing carbon emissions according to claim 1, characterized in that: An O2 temperature sensor and an O2 pressure sensor are also provided on the pipeline connecting the gasifier and the buffer tank; a CO2 temperature sensor and a CO2 pressure sensor are also provided on the CO2 pipeline; and an auxiliary gas temperature sensor and an auxiliary gas pressure sensor are also provided at the outlet of the buffer tank; The signal output ends of the O2 temperature sensor, the O2 pressure sensor, the CO2 temperature sensor, the CO2 pressure sensor, the combustion-supporting gas temperature sensor and the combustion-supporting gas pressure sensor are all signal-connected to the signal input end of the controller.

3. A method for producing blue carbon using a blue carbon production system for reducing carbon emissions as described in claim 1 or 2, characterized in that: The following steps are involved: (1) Preparation of combustion-supporting gas: The liquid oxygen in the liquid oxygen storage tank is vaporized by a vaporizer and then mixed with CO2 in a buffer tank to obtain a combustion-supporting gas with an oxygen volume content of 20% to 30%; (2) Coking: a portion of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) is fed into a coking furnace, and oxygen reacts with excess lump coal to produce CO and release a large amount of heat; at the same time, CO2 reacts with excess lump coal to produce CO; and most of the volatile matter in the lump coal is volatilized under high temperature; finally, raw coal gas with CO as the main component and a semi-coke product with a volatile matter content of 3% to 5% are obtained; (3) Coal gas purification: the raw coal gas obtained in the coking process of step (2) is first sent to a water washing tower to remove particulate matter contained therein, then sent to a detarring tower to remove phenol and naphthalene substances therein, and then sent to a desulfurization tower to remove sulfur contained therein, thereby obtaining pure coal gas; (4) Power generation: another part of the combustion-supporting gas obtained in the preparation of the combustion-supporting gas in step (1) and a part of the coal gas obtained in the coal gas purification in step (3) are sent to a gas turbine to generate electricity through combustion. The high-temperature flue gas generated by the combustion enters the waste heat boiler turbine. The high-temperature flue gas first undergoes heat exchange to generate steam, and the steam then generates electricity. A part of the low-temperature flue gas with a CO2 content of more than 90% discharged after the high-temperature flue gas is cooled by the waste heat boiler turbine is sent as a dilution gas to the buffer tank in the preparation of the combustion-supporting gas in step (1) to be mixed with pure oxygen.

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