Coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology

Abstract

The invention discloses a coupling system of a heat recovery coke oven technology and a low-rank coal pyrolysis technology, which relates to the technical field of coke production and comprises a vertical heat recovery coke oven, a pyrolysis furnace, an oxygen-enriched supply system and a coal gas purification system, the tail end of a total flue of the vertical heat recovery coke oven is communicated with a combustion chamber at the bottom of the pyrolyzing furnace; high-temperature flue gas discharged from the main flue can be subjected to water gas reaction with semicoke at the bottom of the pyrolyzing furnace; the high-temperature flue gas can form warm flue gas which is used for pyrolyzing low-rank coal in the pyrolyzing furnace and generating products of semicoke and dry distillation gas after water gas reaction and heat absorption; a top outlet of the pyrolyzing furnace is communicated with an inlet of the coal gas purification system, the coal gas purification system is used for purifying entering gas, and an outlet of the coal gas purification system outputs purified coal gas; the oxygen-enriched supply system can supply oxygen-enriched gas, and the oxygen-enriched gas is communicated with a combustion chamber at the bottom of the pyrolyzing furnace through an oxygen-enriched supply pipeline. The energy utilization efficiency is improved, the added value of products is optimized and improved, and pollutant emission is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of coke production, and in particular to a coupling system of a heat recovery coke oven technology and a low-rank coal pyrolysis technology. Background Art

[0002] Heat recovery coke ovens are gaining more and more attention as a new type of clean and environmentally friendly coking technology. Heat recovery coke oven coking technology is different from traditional chemical product recovery coke oven technology. The coking process does not recover chemical products in the raw gas, such as tar, coal gas, etc., but converts the raw gas into heat for coke oven heating and recovery. Negative pressure operation is adopted in its production process, and no unorganized emissions, no wastewater, and no waste gas are generated. The flue gas generated meets the emission standards after desulfurization, denitrification, and dust removal. Low-rank coal pyrolysis technology is a method of processing and utilizing non-coking coal, such as lignite, long flame coal and other low-rank coal. Low-rank coal is heated in a pyrolysis furnace isolated from air to produce semi-coke and dry distillation gas. Each ton of coal can produce about 450 kilograms of semi-coke (lignite), 700 cubic meters of dry distillation gas, and the rest is tar, water, etc.

[0003] For heat recovery coke oven technology, the raw coal gas produced during the coking process is rich in combustible components such as hydrogen, carbon monoxide, methane, and tar. The amount of raw coal gas produced per ton of coking coal is about 400 cubic meters. Burning 40% can meet the heat requirements of the coking process, and the remaining 60% of the combustible gas needs to be supplemented and converted into heat and discharged to the waste heat boiler with the high-temperature flue gas. Due to the low thermal efficiency of the waste heat boiler, the heat contained in the high-temperature flue gas is not fully utilized. In particular, the main components of the flue gas after combustion are water vapor and carbon dioxide. The waste heat boiler cannot effectively recover the latent heat therein, resulting in energy waste; the entire low-rank coal pyrolysis technology (lignite processing) also has common problems: 1. There are few application scenarios for semi-coke (lignite), and the demand for calcium carbide and ferroalloy smelting in the traditional market is limited. The replacement of blast furnace injection with pulverized coal injection is gradually increasing, resulting in fierce competition in the lignite and semi-coke market and low product prices. 2. Due to its poor quality and low calorific value, the main application scenarios of dry distillation gas are combustion for power generation, coal tar hydrogenation and magnesium calcination, of which power generation consumption accounts for more than 60%. 3. The current pyrolysis production process adopts positive pressure operation, which produces wastewater and exhaust gas, causing serious pollution, affecting the production and development of low-rank coal pyrolysis / lignite. 4. The dry distillation gas has a large gas output, and part of it can be returned to the furnace for heating to meet the needs of the pyrolysis furnace. A large amount of surplus dry distillation gas needs to be reasonably processed and utilized to improve the economic benefits of the enterprise. 5. In the production operation of low-rank coal pyrolysis, there is a large heat loss in the furnace body, equipment, and process, and the energy consumption is high.

[0004] Therefore, based on this, it is necessary to provide a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology to fully utilize their respective advantages and achieve the effect of 1+1 greater than 2. Summary of the invention

[0005] The purpose of the present invention is to provide a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology to solve the problems existing in the above-mentioned prior art, improve energy utilization efficiency, optimize and increase product added value, and reduce pollutant emissions.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology, comprising a vertical heat recovery coke oven, a pyrolysis furnace, an oxygen-enriched supply system and a gas purification system; the end of the main flue of the vertical heat recovery coke oven is connected to the bottom combustion chamber of the pyrolysis furnace; the high-temperature flue gas discharged from the main flue can react with the bottom semi-coke of the pyrolysis furnace to produce water-gas reaction; the high-temperature flue gas can form medium-temperature flue gas after absorbing heat through the water-gas reaction, and the medium-temperature flue gas is used to pyrolyze the low-rank coal in the pyrolysis furnace and produce product semi-coke and dry distillation gas, and the product semi-coke falls in the pyrolysis furnace due to gravity and can react with the high-temperature flue gas below to produce water-gas reaction; the top outlet of the pyrolysis furnace is connected to the inlet of the gas purification system, the gas purification system is used to purify the incoming gas, and the outlet of the gas purification system produces clean gas and medium- and low-temperature tar; the oxygen-enriched supply system can supply oxygen-enriched gas, and the oxygen-enriched gas is connected to the bottom combustion chamber of the pyrolysis furnace through an oxygen-enriched supply pipeline.

[0008] Preferably, the oxygen-enriched supply system has a carbon dioxide inlet and a pure oxygen inlet; the coal gas purification system has a carbon dioxide outlet, and the carbon dioxide inlet is connected to the carbon dioxide outlet; the pure oxygen inlet is used to be connected to the output port of the pure oxygen supply equipment.

[0009] Preferably, the oxygen-rich gas is communicated with each combustion chamber of the vertical heat recovery coke oven through the coke oven combustion-supporting gas channel of the vertical heat recovery coke oven.

[0010] Preferably, the carbon dioxide outlet is communicated with a gas sealing device of a coal feeding system of the pyrolysis furnace.

[0011] Preferably, the bottom of the pyrolysis furnace has a semi-coke discharge port, and a gate is provided at the semi-coke discharge port, and the gate can change the opening of the semi-coke discharge port.

[0012] Preferably, the coal gas purification system comprises an ammonia water spraying and condensing device, a gas-liquid separation device, a cooling and blowing device, a desulfurization device and a decarbonization device which are arranged in sequence.

[0013] Preferably, the coal gas purification system further comprises a gas holder; the coal gas discharged from the decarbonized coal gas outlet of the decarbonization equipment enters into the gas holder through the inlet of the gas holder.

[0014] Preferably, the oxygen concentration in the oxygen-rich gas is below 30%.

[0015] Preferably, the pyrolysis furnace is arranged on a side of the vertical heat recovery coke oven close to the coking coal tower.

[0016] Preferably, the pyrolysis furnace and the vertical heat recovery coke oven share a resistance wall.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The coupling system of the heat recovery coke oven technology and the low-rank coal pyrolysis technology provided by the present invention provides heat for the pyrolysis furnace through a vertical heat recovery coke oven, and there are unburned raw gas components in its high-temperature flue gas, including hydrogen, carbon monoxide, methane, and hydrocarbon substances. The products after combustion are water vapor and carbon dioxide. The temperature of the high-temperature flue gas is in direct contact with the bottom semi-coke at the bottom of the pyrolysis furnace, wherein the water vapor and the semi-coke react with water gas to generate hydrogen and carbon monoxide, thereby increasing the amount of combustible gas in the flue gas; since the water gas reaction is an endothermic reaction, the temperature of the flue gas is reduced to medium-temperature flue gas after the reaction, and the medium-temperature flue gas is used as a hot carrier gas to heat the low-rank coal in the pyrolysis furnace, and the low-rank coal is pyrolyzed to generate products semi-coke and dry distillation gas, which move downward under the action of gravity and continue to react with the high-temperature flue gas below with water gas; finally, the hydrogen and carbon monoxide generated by the dry distillation gas and water gas reaction, and the vertical heat recovery coke oven flue gas The combustible gas brought in by the vertical heat recovery coke oven rises together and enters the gas purification system. After purification by the gas purification system, clean coal gas with a high content of combustible gas is finally obtained; through the coupling of heat recovery coke oven technology and low-rank coal pyrolysis technology, the residual heat of the vertical heat recovery coke oven is fully converted into gasification energy, and some combustible components are retained. The low-rank coal in the pyrolysis furnace is gasified and distilled, which increases the combustible components in the coal gas, so that the quality of the final clean coal gas is improved, providing the possibility for the high added value comprehensive utilization of coal gas, which can be used as a raw material for gas internal combustion engine power generation, as a raw material gas for synthetic ammonia, and as a raw material for preparing methanol and hydrogen production; when the process requires, the oxygen-rich gas introduced into the pyrolysis furnace can be controlled to strengthen the gasification reaction in the pyrolysis furnace, increase the gas production capacity, reduce or no semi-coke production, and control a certain degree of gasification to convert semi-coke into activated semi-coke (activated carbon) with a certain adsorption capacity. Through the coupling of the above two technologies, the effect of 1+1 greater than 2 is achieved, the energy utilization efficiency is improved, the added value of products is optimized and increased, and pollutant emissions are reduced.

[0019] Furthermore, the oxygen-enriched supply system uses pure oxygen to assist combustion, reducing the large amount of nitrogen in the air participating in the combustion process. In the traditional combustion process, the reaction of nitrogen and oxygen at high temperature will produce nitrogen oxides (NOx), which is one of the atmospheric pollutants. In the oxygen-enriched combustion environment, due to the reduction of nitrogen, the generation of nitrogen oxides is significantly reduced, reducing the pollution to the atmospheric environment; by providing pure oxygen and carbon dioxide to the combustion chamber at the bottom of the pyrolysis furnace, the reaction conditions in the pyrolysis furnace can be improved, so that the output and quality of the synthesis gas (carbon monoxide and hydrogen) can be improved.

[0020] Furthermore, the oxygen-rich gas enters each combustion chamber from the gas channels distributed on the combustion-supporting gas channel of the coke oven, and the raw coal gas escaping from the carbonization chamber enters the combustion chamber through the coke oven crossing hole and flows downward. During the downward flow, the raw coal gas contacts and mixes with the oxygen-rich gas entering from the combustion-supporting gas channel in turn for combustion, thereby achieving uniform longitudinal heating in the combustion chamber and reducing the situation of local heat shortage, thereby improving the production efficiency of coke, shortening the coking cycle, and indirectly improving the energy utilization efficiency; the raw coal gas is incompletely oxidized and burned in the vertical fire channel, and the remaining part of the raw coal gas enters the lower part of the vertical heat recovery coke oven together with the combustion products such as water vapor and carbon dioxide, and enters the main flue through the inclined area.

[0021] Furthermore, the carbon dioxide outlet of the coal gas purification system is connected to the gas sealing device of the pyrolysis furnace coal feeding system, so that the carbon dioxide is used for gas sealing. This part of carbon dioxide may have been discharged as waste gas originally, but now it is effectively utilized. During the gas sealing process, carbon dioxide can prevent air from entering the pyrolysis furnace coal feeding system, thereby ensuring the stability of the reaction atmosphere inside the pyrolysis furnace. The stable reaction atmosphere helps the low-rank coal pyrolysis reaction and other related reactions (such as water-gas reaction) in the pyrolysis furnace to proceed more efficiently, because the entry of air may interfere with the reaction, resulting in heat loss or incomplete reaction. This method of using carbon dioxide for gas sealing indirectly improves the energy utilization efficiency of the entire coupled system.

[0022] Furthermore, the degree of reaction between semi-coke and high-temperature flue gas, the gas composition and the quality of semi-coke can be adjusted by adjusting the opening, including the production of active semi-coke. For example, the residence time of semi-coke in the pyrolysis furnace can be controlled. The process of water-gas reaction between semi-coke and high-temperature flue gas at the bottom of the pyrolysis furnace requires a certain amount of time to reach the ideal reaction degree. Reasonable control of the gate opening can make the semi-coke undergo a more appropriate pyrolysis and gasification process in the pyrolysis furnace, thereby improving the quality of the semi-coke.

[0023] Furthermore, through a series of purification processes such as ammonia spraying condensation equipment and gas-liquid separation equipment, impurities such as tar, dust, sulfide and carbon dioxide in the distillation gas are effectively removed to obtain high-quality clean coal gas. The clean coal gas can be used as a chemical raw material for synthesizing high-end chemical products such as methanol and synthetic ammonia, and its added value is much higher than that of unpurified distillation gas; at the same time, the quality of the separated tar products is also improved. After deep processing, a variety of high-value chemical raw materials such as benzene, naphthalene and phenol can be extracted for the production of plastics, dyes, medicines and other products, thereby increasing the economic value of tar.

[0024] Furthermore, the gas pressure in the gasholder can be adjusted according to actual needs. When the gas enters the gasholder, the gasholder can absorb excess pressure; when the gas flows out of the gasholder, the pressure can be increased appropriately. This pressure regulation function allows the gas to burn or chemically react at an appropriate pressure during subsequent transportation and use. The appropriate pressure helps the gas to burn fully or participate in chemical synthesis reactions more effectively, thereby improving energy utilization efficiency. When the gas is stored in the gasholder, some impurities (such as tiny dust particles, trace amounts of sulfides that have not been completely removed, etc.) may further settle under the action of gravity, or react with the wall surface inside the gasholder by adsorption, thereby further optimizing the gas quality. When burning or used as a chemical raw material, high-quality coal gas can release energy or participate in reactions more efficiently, thereby improving energy utilization efficiency; gas tanks can ensure the stability of the quality and pressure of gas supplied to downstream users. For chemical synthesis companies that require high-quality coal gas as a raw material, stable gas quality is the key to producing high-quality chemical products; the existence of gas tanks makes the allocation of gas more flexible, and gas can be allocated to different uses according to market demand and the requirements of different users.

[0025] Furthermore, the oxygen concentration in the oxygen-rich gas is below 30%, which can effectively control the combustion reaction rate in the pyrolysis furnace and the coke oven. If the oxygen concentration is too high, the combustion reaction will be too violent, which may cause the local temperature to be too high, making the heat not evenly distributed and utilized. The appropriate oxygen concentration can make the combustion reaction proceed in a milder manner, so that the heat can be released more continuously and can better match the pyrolysis and coking processes. Compared with the flue gas produced by high-temperature and high-speed combustion caused by high-concentration oxygen, this moderate flue gas temperature and flow rate are more conducive to the transfer and utilization of heat, reduce the loss of heat during the transfer process, and improve the energy utilization efficiency of the entire coupled system.

[0026] Furthermore, the pyrolysis furnace is arranged on one side of the vertical heat recovery coke oven close to the coking coal tower, so that the distance for transporting low-rank coal from the coal tower to the pyrolysis furnace is shortened. During the transportation process, the energy loss caused by long-distance transportation, such as the power consumption of belt conveyor equipment, is reduced. At the same time, the possibility of heat loss of coal during transportation is also reduced, ensuring that the low-rank coal enters the pyrolysis furnace at a relatively high temperature, reducing the energy required for preheating the pyrolysis furnace, thereby improving energy utilization efficiency.

[0027] Furthermore, the pyrolysis furnace and the vertical heat recovery coke oven share a resistance wall, forming an integrated structure of the pyrolysis furnace and the vertical heat recovery coke oven, rationally utilizing space, reducing connecting pipelines, and reducing heat loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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 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.

[0029] Figure 1 A schematic flow chart of the coupling system of the heat recovery coke oven technology and the low-rank coal pyrolysis technology provided by the present invention.

[0030] In the figure:

[0031] 10-vertical heat recovery coke oven; 11-combustion chamber; 12-carbonization chamber; 13-main flue;

[0032] 20-pyrolysis furnace; 21-low-rank coal; 22-semi-coke;

[0033] 30-Gas purification system; 31-Gas-liquid separation equipment; 32-Cooling and blowing equipment; 33-Desulfurization equipment; 34-Decarbonization equipment; 35-Clean gas; 36-Gas cabinet;

[0034] 40- oxygen-enriched supply system;

[0035] 50-coking coal tower; 51-tamping station;

[0036] 60- Drying coal briquettes. DETAILED DESCRIPTION

[0037] 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.

[0038] The purpose of the present invention is to provide a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology to solve the problems existing in the prior art, improve energy utilization efficiency, optimize and increase product added value, and reduce pollutant emissions.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Embodiment 1

[0041] This embodiment provides a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology, such as Figure 1 As shown, it includes a vertical heat recovery coke oven 10, a pyrolysis furnace 20, an oxygen-enriched supply system 40 and a coal gas purification system 30; the end of the main flue 13 of the vertical heat recovery coke oven 10 is connected to the bottom combustion chamber of the pyrolysis furnace 20; the high-temperature flue gas discharged from the main flue 13 can react with the bottom semi-coke 22 of the pyrolysis furnace 20 by water-gas reaction; the high-temperature flue gas can absorb heat through the water-gas reaction to form medium-temperature flue gas, and the medium-temperature flue gas is used to pyrolyze the low-rank coal 21 in the pyrolysis furnace 20 and produce the product semi-coke 22 and dry distillation gas, the product semi-coke 22 falls in the pyrolysis furnace 20 due to gravity and can react with the high-temperature flue gas below to produce water-gas reaction; the top outlet of the pyrolysis furnace 20 is connected to the inlet of the gas purification system 30, the gas purification system 30 is used to purify the incoming gas, and the outlet of the gas purification system 30 produces clean coal gas 35 and medium and low-temperature tar; the oxygen-enriched supply system 40 can supply oxygen-enriched gas, and the oxygen-enriched gas is connected to the bottom combustion chamber of the pyrolysis furnace 20 through an oxygen-enriched supply pipeline.

[0042] The vertical heat recovery coke oven 10 provides heat to the pyrolysis furnace 20. The high-temperature flue gas contains unburned raw gas components, including hydrogen, carbon monoxide, methane, and hydrocarbon substances. The products after combustion are water vapor and carbon dioxide. The temperature of the high-temperature flue gas is in direct contact with the bottom semi-coke 22 at the bottom of the pyrolysis furnace 20, wherein the water vapor reacts with the semi-coke 22 to generate hydrogen and carbon monoxide, thereby increasing the amount of combustible gas in the flue gas. Since the water-gas reaction is an endothermic reaction, the reaction The flue gas temperature is then lowered to become medium-temperature flue gas, which is used as a hot carrier gas to heat the low-rank coal 21 in the pyrolysis furnace 20, causing the low-rank coal 21 to undergo pyrolysis to produce semi-coke 22 and dry distillation gas. The semi-coke 22 moves downward under the action of gravity and continues to react with the high-temperature flue gas below to produce water-gas. Finally, the hydrogen and carbon monoxide generated by the dry distillation gas and water-gas reaction, as well as the combustible gas brought into the flue gas of the vertical heat recovery coke oven 10, rise together (enter the drying area, remove the moisture from the low-rank coal 21, and are removed by the gas collector). The hood enters the riser to the gas purification system 30) and enters the gas purification system 30. After purification by the gas purification system 30, clean coal gas 35 with a high combustible gas content is finally obtained; through the coupling of heat recovery coke oven technology and low-rank coal pyrolysis technology, the residual heat of the vertical heat recovery coke oven 10 is fully converted into gasification energy, and some combustible components are retained. The low-rank coal 21 in the pyrolysis furnace 20 is gasified and distilled, which increases the combustible components in the coal gas, so that the quality of the final clean coal gas 35 is improved, which provides the possibility for the high added value comprehensive utilization of coal gas, and can be used as a raw material for gas internal combustion engine power generation, as well as as a raw material gas for synthetic ammonia, and as a raw material for preparing methanol, hydrogen, etc.; when the process requires, the oxygen-rich gas introduced into the pyrolysis furnace 20 can be controlled to strengthen the gasification reaction in the pyrolysis furnace 20, increase the gas production capacity, reduce or no semi-coke 22, and also control a certain degree of gasification to convert the semi-coke 22 into active semi-coke 22 (activated carbon) with a certain adsorption capacity. Through the coupling of the above two technologies, the effect of 1+1 greater than 2 is achieved, energy utilization efficiency is improved, product added value is optimized and increased, and pollutant emissions are reduced.

[0043] Specifically, the temperature of the high-temperature flue gas in the main flue 13 is controlled at about 1300° C., wherein the components of the high-temperature flue gas include hydrogen, carbon monoxide, methane, carbon dioxide, water vapor, etc. This part of the high-temperature flue gas directly enters the pyrolysis furnace 20, and the chemical energy and thermal energy included in this part of the gas are used to gasify and dry distill the low-rank coal 21.

[0044] Specifically, after the vertical heat recovery coke oven 10 uses oxygen-rich gas to assist combustion, the nitrogen in the coal gas is greatly reduced.

[0045] Among them, the relevant setting description of the vertical heat recovery coke oven 10 is as follows:

[0046] Specifically, a carbonization chamber 12 and a combustion chamber 11 are provided in the vertical heat recovery coke oven 10. The raw coal gas generated during the coking process is led out of the carbonization chamber 12 to the combustion chamber 11. In the combustion chamber 11, the raw coal gas and the combustion-supporting gas are combined and burned to generate high-temperature flue gas of about 1400°C. Part of the heat of the high-temperature flue gas indirectly heats the coking coal through the furnace wall of the carbonization chamber 12, and the remaining heat is transmitted from the flue gas chute area to the main flue 13 along with the high-temperature flue gas.

[0047] Specifically, other configurations of the vertical heat recovery coke oven 10 are the same as the existing configurations, and will not be described in detail herein.

[0048] Among them, the relevant setting description of the pyrolysis furnace 20 is as follows:

[0049] Specifically, a vertical pyrolysis furnace 20 is used.

[0050] In the optional scheme of this embodiment, it is more preferred that the pyrolysis furnace 20 has a semi-coke 22 discharge port at the bottom, and a gate is provided at the semi-coke 22 discharge port, and the gate can change the opening of the semi-coke 22 discharge port. The degree of reaction between the semi-coke 22 and the high-temperature flue gas can be adjusted by adjusting the opening, and the gas composition and the quality of the semi-coke 22 can be adjusted, including the production of active semi-coke, such as controlling the residence time of the semi-coke 22 in the pyrolysis furnace 20. The semi-coke 22 reacts with the high-temperature flue gas at the bottom of the pyrolysis furnace 20. The process of water-gas reaction and the like requires a certain amount of time to reach the ideal reaction degree; reasonable control of the gate opening can make the semi-coke 22 undergo a more suitable pyrolysis and gasification process in the pyrolysis furnace 20, thereby improving the quality of the semi-coke 22.

[0051] Among them, the relevant setting description of the oxygen-enriched supply system 40 is as follows:

[0052] In the optional scheme of this embodiment, it is more preferred that the oxygen concentration in the oxygen-enriched gas is below 30%. The oxygen concentration in the oxygen-enriched gas is below 30%, which can effectively control the combustion reaction rate in the pyrolysis furnace 20 and the coke oven. If the oxygen concentration is too high, the combustion reaction will be too violent, which may cause the local temperature to be too high, so that the heat cannot be evenly distributed and utilized. The appropriate oxygen concentration can make the combustion reaction proceed in a more gentle manner, so that the heat can be released more continuously, and can better match the pyrolysis and coking processes. Compared with the flue gas produced by high-temperature and high-speed combustion caused by high-concentration oxygen, this moderate flue gas temperature and flow rate are more conducive to the transfer and utilization of heat, reduce the loss of heat during the transfer process, and improve the energy efficiency of the entire coupling system.

[0053] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, the oxygen-enriched gas is connected to each combustion chamber 11 of the vertical heat recovery coke oven 10 through the coke oven combustion-supporting gas channel of the vertical heat recovery coke oven 10. The oxygen-enriched gas enters each combustion chamber 11 through the gas channel distributed on the coke oven combustion-supporting gas channel, and the raw coal gas escaping from the carbonization chamber 12 enters the combustion chamber 11 through the coke oven crossing hole and flows downward. During the downward flow, the raw coal gas sequentially contacts and mixes with the oxygen-enriched gas entering from the combustion-supporting gas channel to achieve longitudinal uniform heating in the combustion chamber 11, reduce the situation of local heat shortage, thereby improving the production efficiency of coke, shortening the coking cycle, and indirectly improving the energy utilization efficiency; considering the temperature resistance of the refractory material in the combustion chamber 11 and the uniformity of the coke oven heating, the raw coal gas is incompletely oxidized and burned in the vertical fire channel, and the remaining part of the raw coal gas enters the lower part of the vertical heat recovery coke oven 10 together with the combustion products such as water vapor and carbon dioxide, and enters the main flue 13 through the inclined channel area.

[0054] In the optional scheme of this embodiment, it is more preferred that the oxygen-enriched supply system 40 has a carbon dioxide inlet and a pure oxygen inlet; the coal gas purification system 30 has a carbon dioxide outlet, and the carbon dioxide inlet is connected to the carbon dioxide outlet; the pure oxygen inlet is used to be connected to the output port of the pure oxygen supply device. The oxygen-enriched supply system 40 uses pure oxygen to assist combustion, which reduces the large amount of nitrogen in the air participating in the combustion process. In the traditional combustion process, nitrogen and oxygen react at high temperature to produce nitrogen oxides (NOx), which is one of the atmospheric pollutants. In the oxygen-enriched combustion environment, due to the reduction of nitrogen, the amount of nitrogen oxides generated is significantly reduced, reducing the pollution to the atmospheric environment; by providing pure oxygen and carbon dioxide to the bottom combustion chamber of the pyrolysis furnace 20, the reaction conditions in the pyrolysis furnace 20 can be improved, so that the output and quality of the synthesis gas (carbon monoxide and hydrogen) can be improved.

[0055] Specifically, the oxygen-enriched supply system 40 uses existing gas mixing equipment to mix various gases and supplies them to necessary locations through the existing gas supply equipment.

[0056] Specifically, the oxygen-rich gas mainly contains carbon dioxide and oxygen, and may also contain water vapor and the like.

[0057] Among them, the relevant setting description of the gas purification system 30 is as follows:

[0058] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, the coal gas purification system 30 includes an ammonia water spraying and condensing device, a gas-liquid separation device 31, a cooling and blowing device 32, a desulfurization device 33 and a decarbonization device 34 which are arranged in sequence. Through a series of purification processes such as the ammonia water spraying and condensing device and the gas-liquid separation device 31, impurities such as tar, dust, sulfide and carbon dioxide in the dry distillation gas are effectively removed to obtain high-quality clean coal gas 35. The clean coal gas 35 can be used as a chemical raw material for synthesizing high-end chemical products such as methanol and synthetic ammonia, and its added value is much higher than that of the unpurified dry distillation gas; at the same time, the quality of the separated tar product is also improved. After deep processing, various high-value chemical raw materials such as benzene, naphthalene and phenol can be extracted, which can be used to produce plastics, dyes, medicines and other products, thereby improving the economic value of tar.

[0059] Specifically, the ammonia spraying and condensing equipment, gas-liquid separation equipment 31, cooling and blowing equipment 32, desulfurization equipment 33 and decarbonization equipment 34 in the coal gas purification system 30 are all existing equipment and will not be described in detail here; ammonia spraying is used for cooling; the ammonia, tar, phenol water, etc. separated by the gas-liquid separation equipment 31 are de-ammonia evaporated, tar processed, and treated in the wastewater treatment unit; the cooling and blowing equipment 32 uses a blower to send gas to the desulfurization equipment 33; the desulfurization equipment 33 adopts wet desulfurization, and the generated sulfur paste is used for acid production; the decarbonization equipment 34 adopts PSA method for decarbonization, and the separated carbon dioxide is partly used for gas sealing of the pyrolysis furnace 20 coal feeding system to prevent air from entering the gas system during the coal feeding process, and partly used to be mixed with pure oxygen to produce oxygen-rich gas for combustion of the vertical heat recovery coke oven 10.

[0060] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, the coal gas purification system 30 also includes a gas tank 36; the coal gas discharged from the decarbonized coal gas outlet of the decarbonization equipment 34 enters the gas tank 36 through the inlet of the gas tank 36. The coal gas pressure in the gas tank 36 can be adjusted according to actual needs. When the coal gas enters the gas tank 36, the gas tank 36 can absorb the excess pressure; when the coal gas flows out of the gas tank 36, the pressure can be appropriately increased. This pressure regulation function can make the coal gas burn or chemically react at a suitable pressure during the subsequent transportation and use process. The suitable pressure helps the coal gas to fully burn or participate in chemical synthesis reactions more effectively, thereby improving energy utilization efficiency; when the coal gas is stored in the gas tank 36, some impurities (such as tiny dust particles, trace amounts of sulfides that are not completely removed, etc.) may further settle under the action of gravity, or react with the wall surface in the gas tank 36 by adsorption, etc., so that the coal gas quality is further optimized. When burning or used as a chemical raw material, high-quality coal gas can release energy or participate in reactions more efficiently, thereby improving energy utilization efficiency; the gas tank 36 can ensure the stability of the quality and pressure of the gas supplied to downstream users. For chemical synthesis companies that require high-quality coal gas as a raw material, stable gas quality is the key to producing high-quality chemical products; the existence of the gas tank 36 makes the allocation of gas more flexible, and the gas can be allocated to different usage methods according to market demand and the requirements of different users.

[0061] In the optional scheme of this embodiment, it is more preferred that Figure 1 As shown, the carbon dioxide outlet is connected to the gas sealing device of the coal feeding system of the pyrolysis furnace 20. The carbon dioxide outlet of the coal gas purification system 30 is connected to the gas sealing device of the coal feeding system of the pyrolysis furnace 20, so that carbon dioxide is used for gas sealing. This part of carbon dioxide may have been discharged as waste gas, but now it is effectively utilized. During the gas sealing process, carbon dioxide can prevent air from entering the coal feeding system of the pyrolysis furnace 20, ensuring the stability of the reaction atmosphere inside the pyrolysis furnace 20. The stable reaction atmosphere helps the pyrolysis reaction of the low-rank coal 21 in the pyrolysis furnace 20 and other related reactions (such as water-gas reaction) to proceed more efficiently, because the entry of air may interfere with the reaction, resulting in heat loss or incomplete reaction. This method of using carbon dioxide for gas sealing indirectly improves the energy efficiency of the entire coupling system.

[0062] Among them, about other related settings description:

[0063] In the optional scheme of this embodiment, it is more preferred that Figure 1As shown, the pyrolysis furnace 20 is arranged on one side of the vertical heat recovery coke oven 10 close to the coking coal coal tower 50. The pyrolysis furnace 20 is arranged on one side of the vertical heat recovery coke oven 10 close to the coking coal coal tower 50, so that the distance of the low-rank coal 21 from the coal tower to the pyrolysis furnace 20 is shortened. During the transportation process, the energy loss caused by long-distance transportation is reduced, such as the power consumption of the belt conveyor equipment, etc. At the same time, the possibility of heat loss of the coal during transportation is also reduced, ensuring that the low-rank coal 21 enters the pyrolysis furnace 20 at a relatively high temperature, reducing the energy required for preheating the pyrolysis furnace 20, thereby improving energy utilization efficiency.

[0064] In the optional scheme of this embodiment, it is more preferred that the pyrolysis furnace 20 and the vertical heat recovery coke oven 10 share a resistance wall. The pyrolysis furnace 20 and the vertical heat recovery coke oven 10 share a resistance wall, forming an integrated structure of the pyrolysis furnace 20 and the vertical heat recovery coke oven 10, rationally utilizing space, reducing connecting pipelines, and reducing heat loss.

[0065] Specifically, a necessary tamping station 51 is also provided at the coking coal tower 50, which is an existing equipment and will not be described in detail here.

[0066] Specifically, the low-rank coal 21 in the pyrolysis furnace 20 is dried in the coal drying tower 60 and then added into the pyrolysis furnace 20 .

[0067] Specifically, the coupling system of the heat recovery coke oven technology and the low-rank coal pyrolysis technology provided in this embodiment has the following advantages:

[0068] 1. The existing vertical heat recovery coke oven coking uses air as the combustion-supporting gas, and most of the high-temperature flue gas discharged is nitrogen, water vapor, carbon dioxide, and a small amount of unburned hydrogen and carbon monoxide; each ton of coking coal can produce about 400 cubic meters of raw gas, and burning 40% can meet the heat requirements of the coking process. The remaining 60% of the combustible gas needs to be supplemented and converted into heat and discharged to the waste heat boiler with the high-temperature flue gas. Due to the low thermal efficiency of the waste heat boiler, the heat contained in the high-temperature flue gas is not fully utilized. In particular, the main components of the flue gas after combustion are water vapor and carbon dioxide, and the waste heat boiler cannot effectively recover the latent heat therein, resulting in energy waste; this coupling system uses oxygen-rich gas as the combustion-supporting gas, and through the coupling of the heat recovery coke oven and the pyrolysis furnace, fully utilizes their respective advantages to achieve the effect of 1+1 greater than 2.

[0069] 2. The heat recovery coke oven is coupled with the low-rank coal pyrolysis furnace. The high-temperature flue gas from the heat recovery coke oven directly enters the pyrolysis furnace as a heat carrier. The water vapor and carbon dioxide in the high-temperature flue gas undergo an endothermic gasification reaction with the semi-coke from the low-rank coal pyrolysis furnace. The thermal energy of the high-temperature flue gas is effectively utilized. After the gasification reaction, the temperature of the high-temperature flue gas drops to about 700°C, which is suitable for low-rank coal pyrolysis. At the same time, the water vapor and carbon dioxide in the high-temperature flue gas are partially converted into hydrogen and carbon monoxide, which has a carbon reduction effect and increases the content of combustible gases in the flue gas.

[0070] 3. Low-rank coal is pyrolyzed using combustible gas containing a certain amount of hydrogen and carbon monoxide as a heat carrier. The combustible gas content in the pyrolysis gas is relatively high. During the pyrolysis process, hydrogen is beneficial to increase the yield of medium-temperature tar in the pyrolysis product, thereby increasing the yield of light oil.

[0071] 4. The heat recovery coke oven is coupled with low-rank coal pyrolysis. The low-rank coal pyrolysis furnace replaces the traditional waste heat boiler to recover heat. The heat recovery coke oven has high heat conversion efficiency of high-temperature flue gas. The products are high-value-added combustible gas, light oil, and active semi-coke with good economic benefits.

[0072] 5. The heat recovery coke oven is coupled with low-rank coal pyrolysis, and the entire system adopts micro-negative pressure operation (the heat recovery coke oven can adopt the negative pressure environment of the low-rank coal pyrolysis furnace), which reduces the system's unorganized emissions and reduces the environmental odor.

[0073] 6. The heat recovery coke oven is coupled with low-rank coal pyrolysis. The low-rank coal pyrolysis furnace is simple to operate and has a significantly lower failure rate than the waste heat boiler, reducing the impact of waste heat boiler accidents on the heat recovery coke oven.

[0074] 7. The heat recovery coke oven is coupled with low-rank coal pyrolysis. The low-rank coal pyrolysis furnace replaces the waste heat boiler, and the production water consumption is greatly reduced, which is suitable for arid and water-scarce areas.

[0075] 8. The heat recovery coke oven is coupled with the pyrolysis of low-rank coal, and the heat of high-temperature flue gas is converted into combustible gas and oil products, and active semi-coke, the products of which can be used for power generation, making it suitable for projects far away from the power grid and with low on-grid electricity prices.

[0076] 9. When oxygen-rich gas is used as the combustion-supporting gas for the heat recovery coke oven, the carbon dioxide separated from the pyrolysis gas is used to mix with pure oxygen, so that the thermal efficiency of the heat recovery coke oven is improved, the high-temperature flue gas does not contain nitrogen, the residual combustible gas content in the coke oven flue gas is increased, and the ratio of water vapor and carbon dioxide is increased, which is conducive to these gases being used as gasification gas and pyrolysis carrier gas for the pyrolysis furnace, and is conducive to the gasification reaction of semi-coke and the pyrolysis of low-rank coal, and the quality of pyrolysis gas and oil products is further improved.

[0077] 10. The heat recovery coke oven coupled with low-rank coal pyrolysis has expanded the scope of coal resource utilization (coking coal + low-rank coal), increased product varieties (coke + activated semi-coke + clean coal gas + light oil + electricity), and improved the market competitiveness and flexibility of the project.

[0078] 11. Low-rank coal pyrolysis furnaces include internal heating type and external heating type, and the structural forms include vertical moving bed and rotary kiln type.

[0079] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology, characterized in that: It includes vertical heat recovery coke oven, pyrolysis furnace, oxygen-enriched supply system and coal gas purification system; The end of the main flue of the vertical heat recovery coke oven is connected to the bottom combustion chamber of the pyrolysis furnace; the high-temperature flue gas discharged from the main flue can react with the bottom semi-coke of the pyrolysis furnace by water-gas reaction; the high-temperature flue gas can absorb heat through the water-gas reaction to form medium-temperature flue gas, and the medium-temperature flue gas is used to pyrolyze the low-rank coal in the pyrolysis furnace and produce product semi-coke and dry distillation gas, and the product semi-coke falls in the pyrolysis furnace due to gravity and can react with the high-temperature flue gas below by water-gas reaction; The top outlet of the pyrolysis furnace is connected to the inlet of the coal gas purification system, the coal gas purification system is used to purify the incoming gas, and the outlet of the coal gas purification system produces clean coal gas and medium and low temperature tar; The oxygen-rich supply system can supply oxygen-rich gas, and the oxygen-rich gas is communicated with the bottom combustion chamber of the pyrolysis furnace through an oxygen-rich supply pipeline.

2. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The oxygen-enriched supply system has a carbon dioxide inlet and a pure oxygen inlet; The coal gas purification system has a carbon dioxide outlet, and the carbon dioxide inlet is connected to the carbon dioxide outlet; The pure oxygen inlet is used to communicate with the output port of the pure oxygen supply equipment.

3. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The oxygen-enriched gas is communicated with each combustion chamber of the vertical heat recovery coke oven through the coke oven combustion-supporting gas channel of the vertical heat recovery coke oven.

4. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 2 is characterized by: The carbon dioxide outlet is communicated with a gas sealing device of a coal supply system of the pyrolysis furnace.

5. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The bottom of the pyrolysis furnace is provided with a semi-coke discharge port, and a gate is arranged at the semi-coke discharge port, and the gate can change the opening degree of the semi-coke discharge port.

6. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The coal gas purification system comprises an ammonia water spraying and condensing device, a gas-liquid separation device, a cooling and blowing device, a desulfurization device and a decarbonization device which are arranged in sequence.

7. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 6 is characterized by: The coal gas purification system also includes a gas holder; the coal gas discharged from the decarbonized coal gas outlet of the decarbonization equipment enters the gas holder through the inlet of the gas holder.

8. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The oxygen concentration in the oxygen-rich gas is below 30%.

9. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1 is characterized by: The pyrolysis furnace is arranged on a side of the vertical heat recovery coke oven close to the coking coal tower.

10. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 9 is characterized in that: The pyrolysis furnace and the vertical heat recovery coke oven share a resisting wall.

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