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

Abstract

The utility model 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] This utility model relates to the field of coke production technology, and in particular to a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology. Background Technology

[0002] Heat recovery coke ovens are gaining increasing attention as a clean and environmentally friendly new coking technology. Unlike traditional chemical recovery coke oven technology, heat recovery coke ovens do not recover chemical products from raw coal gas, such as tar and coal gas. Instead, they convert the raw coal gas into heat for coke oven heating and recovery. The production process uses negative pressure operation, producing no fugitive emissions, no wastewater, and no waste gas. The generated flue gas undergoes desulfurization, denitrification, and dust removal to meet emission standards. Low-rank coal pyrolysis technology is a method for processing and utilizing non-coking coals, such as lignite and long-flame coal. Low-rank coal is heated in an air-isolated pyrolysis furnace to produce semi-coke and carbon dioxide gas. Each ton of coal can produce approximately 450 kg of semi-coke (lignite) and 700 cubic meters of carbon dioxide gas, with the remainder being 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. Each ton of coking coal can produce approximately 400 cubic meters of raw coal gas. Combustion of 40% is sufficient to meet the heat requirements of the coking process, while the remaining 60% of combustible gas needs to be supplemented and converted into heat before being 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, resulting in energy waste. The entire low-rank coal pyrolysis technology (semi-coke processing) also has common problems: 1. Limited application scenarios for semi-coke (semi-coke). The demand in the traditional market for calcium carbide and ferroalloy smelting is limited, and the replacement of pulverized coal with blast furnace injection is gradually increasing, resulting in fierce competition in the semi-coke market and low product prices. 2. Due to its poor quality and low calorific value, the main applications of pyrolysis gas are combustion power generation, coal tar hydrogenation, and magnesium calcination, with power generation accounting for over 60% of its consumption. 3. Current pyrolysis production processes utilize positive pressure operation, generating wastewater and waste gas, causing severe pollution and impacting the production and development of low-rank coal pyrolysis / semi-coke. 4. The large volume of pyrolysis gas produced can be partially recycled back into the furnace to meet the needs of the pyrolysis furnace; the surplus gas needs to be rationally processed and utilized to improve the economic efficiency of enterprises. 5. In the operation of low-rank coal pyrolysis, heat loss is significant in the furnace, equipment, and processes, resulting in high energy consumption.

[0004] Therefore, it is necessary to provide a coupled system of heat recovery coke oven technology and low-rank coal pyrolysis technology to make full use of their respective advantages and achieve a 1+1 greater than 2 effect. Utility Model Content

[0005] The purpose of this invention is to provide a coupled 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.

[0006] To achieve the above objectives, this utility model provides the following solution:

[0007] This invention provides a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology, including 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 in a water-gas reaction. The high-temperature flue gas can absorb heat through the water-gas reaction to form medium-temperature flue gas, which is used to pyrolyze the low-rank coal in the pyrolysis furnace to produce product semi-coke and dry distillation gas. The product semi-coke falls in the pyrolysis furnace under gravity and can react with the high-temperature flue gas below in a water-gas reaction. The top outlet of the pyrolysis furnace is connected to the inlet of the gas purification system, which is used to purify the incoming gas, and the outlet of the gas purification system produces clean coal gas and medium-low temperature tar. The oxygen-enriched supply system can supply oxygen-enriched gas, which 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 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 connect to the output port of the pure oxygen supply equipment.

[0009] Preferably, the oxygen-enriched gas is connected to each combustion chamber of the vertical heat recovery coke oven through the coke oven combustion gas channel of the vertical heat recovery coke oven.

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

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

[0012] Preferably, the gas purification system includes, in sequence, an ammonia water spraying and condensing device, a gas-liquid separation device, a cooling blower, a desulfurization device, and a decarbonization device.

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

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

[0015] Preferably, the pyrolysis furnace is located on the side of the vertical heat recovery coke oven near the coking coal tower.

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

[0017] The present invention achieves the following technical advantages over the prior art:

[0018] This invention provides a coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology. A vertical heat recovery coke oven provides heat to the pyrolysis furnace. The high-temperature flue gas contains unburned raw coal gas components, including hydrogen, carbon monoxide, methane, and hydrocarbons. The products of combustion are water vapor and carbon dioxide. The high-temperature flue gas directly contacts the bottom semi-coke of the pyrolysis furnace, where water vapor reacts with the semi-coke to produce hydrogen and carbon monoxide, thus increasing the amount of combustible gas in the flue gas. Since the water-gas reaction is endothermic, the flue gas temperature decreases after the reaction, becoming medium-temperature flue gas. This medium-temperature flue gas acts as a heat carrier gas to heat the low-rank coal in the pyrolysis furnace. The low-rank coal undergoes pyrolysis, producing semi-coke and carbon dioxide. The semi-coke moves downwards under gravity and continues to react with the high-temperature flue gas below in a water-gas reaction. Finally, the carbon dioxide, the hydrogen and carbon monoxide produced by the water-gas reaction, and the flue gas from the vertical heat recovery coke oven... Combustible gases introduced into the gas rise and enter the gas purification system. After purification by the system, clean gas with a high content of combustible gases is 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 undergoes gasification and dry distillation, increasing the combustible components in the gas and improving the quality of the final clean gas. This provides the possibility for the comprehensive utilization of gas with high added value. It can be used as a raw material for gas-fired internal combustion engine power generation, as a feed gas for ammonia synthesis, and as a raw material for methanol and hydrogen production. When the process requires it, the gasification reaction in the pyrolysis furnace can be enhanced by controlling the oxygen-enriched gas introduced into the pyrolysis furnace, increasing gas production capacity and reducing or eliminating the production of semi-coke. Alternatively, a certain degree of gasification can be controlled to convert semi-coke into activated semi-coke (activated carbon) with a certain adsorption capacity. Through the coupling of the above two technologies, a 1+1 greater than 2 effect is achieved, improving energy utilization efficiency, optimizing and increasing product added value, and reducing pollutant emissions.

[0019] Furthermore, the oxygen-enriched supply system uses pure oxygen for combustion, reducing the amount of nitrogen in the air involved in the combustion process. In traditional combustion, nitrogen and oxygen react at high temperatures to produce nitrogen oxides (NOx), which are one of the air pollutants. However, in an oxygen-enriched combustion environment, due to the reduction of nitrogen, the amount of nitrogen oxides generated is significantly reduced, thus mitigating pollution to the atmospheric environment. By supplying pure oxygen and carbon dioxide to the combustion chamber at the bottom of the pyrolysis furnace, the reaction conditions inside the pyrolysis furnace can be improved, thereby increasing the yield and quality of syngas (carbon monoxide and hydrogen).

[0020] Furthermore, oxygen-enriched gas enters each combustion chamber through gas channels distributed on the coke oven combustion gas channel. The raw coal gas escaping from the carbonization chamber enters the combustion chamber through the coke oven cross-hole and flows downward. During the downward flow, the raw coal gas comes into contact with and mixes with the oxygen-enriched gas entering from the combustion gas channel, achieving uniform longitudinal heating in the combustion chamber, reducing local heat deficiency, thereby improving coke production efficiency, shortening the coking cycle, and indirectly improving energy utilization efficiency. The raw coal gas undergoes incomplete oxidation combustion in the vertical flue. The remaining portion of the raw coal gas, along with combustion products such as water vapor and carbon dioxide, enters the lower part of the vertical heat recovery coke oven and enters the main flue through the inclined section.

[0021] Furthermore, the carbon dioxide outlet of the gas purification system is connected to the gas sealing device of the coal feeding system of the pyrolysis furnace, so that the carbon dioxide is used for gas sealing. This part of the carbon dioxide, which might have been emitted as waste gas, is now effectively utilized. During the gas sealing process, the carbon dioxide can prevent air from entering the coal feeding system of the pyrolysis furnace, ensuring a stable reaction atmosphere inside the pyrolysis furnace. A stable reaction atmosphere helps the pyrolysis reaction of low-rank coal 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, by adjusting the gate opening, the degree of reaction between the semi-coke and the high-temperature flue gas can be adjusted, thereby regulating the composition of the gas and the quality of the semi-coke, including the production of active semi-coke. For example, the residence time of the semi-coke in the pyrolysis furnace can be controlled. The process of the semi-coke reacting with the high-temperature flue gas at the bottom of the pyrolysis furnace and undergoing water-gas reaction requires a certain amount of time to reach the ideal reaction degree. Reasonably controlling the gate opening can enable the semi-coke to undergo a more suitable 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 spray condensation equipment and gas-liquid separation equipment, impurities such as tar, dust, sulfides, and carbon dioxide in the dry distillation gas are effectively removed, resulting in high-quality clean coal gas. This clean coal gas can be used as a chemical raw material to synthesize high-end chemical products such as methanol and ammonia, and its added value is far higher than that of unpurified dry distillation gas. At the same time, the quality of the separated tar products is also improved. After further processing, it can be used to extract various high-value chemical raw materials such as benzene, naphthalene, and phenol, which can be used to produce products such as plastics, dyes, and pharmaceuticals, thereby increasing the economic value of the tar.

[0024] Furthermore, the gas pressure inside the gas holder can be adjusted according to actual needs. When gas enters the gas holder, it can absorb excess pressure; when gas flows out of the gas holder, it can appropriately increase the pressure. This pressure regulation function allows the gas to undergo combustion or chemical reactions at a suitable pressure during subsequent transportation and use. A suitable pressure helps the gas to burn completely or participate more effectively in chemical synthesis reactions, thereby improving energy utilization efficiency. When the gas is stored in the gas holder, some impurities (such as tiny dust particles, trace amounts of incompletely removed sulfides, etc.) may further settle under gravity or undergo adsorption reactions with the walls inside the gas holder, thereby further optimizing the gas quality. High-quality coal gas can release energy or participate in reactions more efficiently when burned or used as a chemical raw material, thus improving energy utilization efficiency. Gas holders can ensure the stability of coal gas quality and pressure supplied to downstream users. For chemical synthesis enterprises that require high-quality coal gas as raw material, stable coal gas quality is the key to producing high-quality chemical products. The existence of gas holders makes the allocation of coal gas more flexible. According to market demand and the requirements of different users, coal gas can be allocated to different uses.

[0025] Furthermore, an oxygen concentration below 30% in oxygen-enriched gas can effectively control the combustion reaction rate in the pyrolysis furnace and coke oven. If the oxygen concentration is too high, the combustion reaction will be too violent, which may lead to excessively high local temperatures, making it impossible to distribute and utilize heat evenly. An appropriate oxygen concentration allows the combustion reaction to proceed in a more gentle manner, enabling the heat to be released more continuously and better matching the pyrolysis and coking processes. Compared with the flue gas produced by high-temperature and high-speed combustion caused by high oxygen concentration, this moderate flue gas temperature and flow rate are more conducive to heat transfer and utilization, reducing heat loss during the transfer process and improving the energy utilization efficiency of the entire coupled system.

[0026] Furthermore, the pyrolysis furnace is located on the side of the vertical heat recovery coke oven close to the coking coal tower, which shortens the distance that low-rank coal needs to be transported from the coal tower to the pyrolysis furnace. During the transportation process, energy losses caused by long-distance transportation, such as the power consumption of belt conveyors, are reduced. At the same time, the possibility of heat loss during coal transportation is also reduced, ensuring that 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 common resisting wall, forming an integrated structure that makes reasonable use of space, reduces connecting pipelines, and minimizes heat loss. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the process of the coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology provided by this utility model.

[0030] In the picture:

[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 blower equipment; 33-Desulfurization equipment; 34-Decarbonization equipment; 35-Clean coal gas; 36-Gas holder;

[0034] 40-Oxygen-enriched supply system;

[0035] 50 - Coking coal tower; 51 - Tamping station;

[0036] 60 - Coal drying tower. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] The purpose of this invention is to provide a coupled 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] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Example 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, the system includes a vertical heat recovery coke oven 10, a pyrolysis furnace 20, an oxygen-enriched supply system 40, and a 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 in a water-gas reaction. After absorbing heat through the water-gas reaction, the high-temperature flue gas forms medium-temperature flue gas, which is used to pyrolyze the low-rank coal 21 in the pyrolysis furnace 20 to produce the product semi-coke 22. The product semi-coke 22 falls within the pyrolysis furnace 20 under gravity and reacts with the high-temperature flue gas below to form a water-gas reaction. The top outlet of the pyrolysis furnace 20 is connected to the inlet of the gas purification system 30, which is used to purify the incoming gas. The outlet of the gas purification system 30 produces clean gas 35 and medium-low temperature tar. The oxygen-enriched supply system 40 can supply oxygen-enriched gas, which 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. Its high-temperature flue gas contains unburned raw coal gas components, including hydrogen, carbon monoxide, methane, and hydrocarbons. The products of combustion are water vapor and carbon dioxide. The high-temperature flue gas is in direct contact with the bottom semi-coke 22 of the pyrolysis furnace 20. The water vapor reacts with the semi-coke 22 in a water-gas reaction, producing hydrogen and carbon monoxide, thus increasing the amount of combustible gas in the flue gas. Since the water-gas reaction is endothermic, the reaction... The flue gas temperature decreases to medium-temperature flue gas, which acts as a heat carrier gas to heat the low-rank coal 21 in the pyrolysis furnace 20. The low-rank coal 21 undergoes pyrolysis, producing semi-coke 22 and carbon dioxide gas. The semi-coke 22 moves downward under gravity and continues to react with the high-temperature flue gas below, undergoing a water-gas reaction. Finally, the hydrogen and carbon monoxide generated by the carbon dioxide gas and water-gas reaction, along with the combustible gas introduced from the flue gas of the vertical heat recovery coke oven 10, rise together (entering the drying zone, carrying away the moisture from the low-rank coal 21, and being collected by the gas collector). The gas enters the riser pipe and then enters the gas purification system 30. After purification by the gas purification system 30, the final clean coal gas 35 with a high combustible gas content is 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 undergoes gasification and dry distillation, which increases the combustible components in the coal gas, thereby improving the quality of the final clean coal gas 35. This provides the possibility for the comprehensive utilization of coal gas with high added value. It can be used as a raw material for gas internal combustion engine power generation, as a raw material for ammonia synthesis, and as a raw material for methanol production, hydrogen production, etc. When the process requires it, the gasification reaction in the pyrolysis furnace 20 can be enhanced by controlling the oxygen-enriched gas introduced into the pyrolysis furnace 20, increasing the gas production capacity and reducing or eliminating the production of semi-coke 22. Alternatively, a certain degree of gasification can be controlled to convert the semi-coke 22 into activated semi-coke 22 (activated carbon) with a certain adsorption capacity. By coupling the two technologies mentioned above, a 1+1 greater than 2 effect can be achieved, improving energy efficiency, optimizing and increasing product added value, and reducing pollutant emissions.

[0043] Specifically, the temperature of the high-temperature flue gas in the main flue duct 13 is controlled at around 1300℃. The components of the high-temperature flue gas include hydrogen, carbon monoxide, methane, carbon dioxide, and water vapor. This portion of high-temperature flue gas directly enters the pyrolysis furnace 20, where the chemical and thermal energy contained in this gas is used to gasify and dry distill the low-rank coal 21.

[0044] Specifically, after the vertical heat recovery coke oven 10 adopts oxygen-enriched gas for combustion, the nitrogen in the coal gas is significantly reduced.

[0045] The following are the relevant settings for the vertical heat recovery coke oven 10:

[0046] Specifically, the vertical heat recovery coke oven 10 is equipped with a carbonization chamber 12 and a combustion chamber 11. 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 produce 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 carried by the high-temperature flue gas from the flue gas inclined area to the main flue 13.

[0047] Specifically, the other settings of the vertical heat recovery coke oven 10 are the same as the existing settings, and will not be repeated here.

[0048] The following are the relevant settings instructions for pyrolysis furnace 20:

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

[0050] In the optional embodiments of this example, a preferred embodiment is that the pyrolysis furnace 20 has a semi-coke 22 outlet at its bottom, and a gate is provided at the semi-coke 22 outlet. The gate can change the opening degree of the semi-coke 22 outlet. By adjusting the opening degree, the degree of reaction between the semi-coke 22 and the high-temperature flue gas can be adjusted, thereby adjusting the composition of the gas and the quality of the semi-coke 22, including the production of active semi-coke. For example, the residence time of the semi-coke 22 in the pyrolysis furnace 20 can be controlled. The process of the semi-coke 22 reacting with the high-temperature flue gas at the bottom of the pyrolysis furnace 20, such as water-gas reaction, requires a certain amount of time to reach the ideal reaction degree. Reasonably controlling the gate opening degree allows the semi-coke 22 to undergo a more suitable pyrolysis and gasification process in the pyrolysis furnace 20, thereby improving the quality of the semi-coke 22.

[0051] The following are the settings instructions for the oxygen-enriched supply system 40:

[0052] In the optional schemes of this embodiment, it is more preferred that the oxygen concentration in the oxygen-enriched gas is below 30%. An oxygen concentration below 30% in the oxygen-enriched gas 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, potentially leading to excessively high local temperatures, preventing the heat from being evenly distributed and utilized. An appropriate oxygen concentration allows the combustion reaction to proceed in a more gentle manner, enabling a more continuous release of heat and better matching the pyrolysis and coking processes. Compared to the high-temperature, high-speed combustion flue gas caused by high oxygen concentrations, this moderate flue gas temperature and flow rate are more conducive to heat transfer and utilization, reducing heat loss during the transfer process and improving the energy efficiency of the entire coupled system.

[0053] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1As shown, oxygen-enriched gas is connected to each combustion chamber 11 of the vertical heat recovery coke oven 10 through the coke oven combustion gas channel. The oxygen-enriched gas enters each combustion chamber 11 through the gas channels distributed on the coke oven combustion gas channel. The raw coal gas escaping from the carbonization chamber 12 enters the combustion chamber 11 through the coke oven cross-hole and flows downward. During the downward flow, the raw coal gas comes into contact with the oxygen-enriched gas entering from the combustion gas channel in sequence, mixes and burns, so as to achieve uniform longitudinal heating in the combustion chamber 11, reduce the situation of insufficient local heat, thereby improving the coke production efficiency, 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 coke oven heating, the raw coal gas undergoes incomplete oxidation combustion in the vertical flue. The remaining part of the raw coal gas enters the lower part of the vertical heat recovery coke oven 10 along with the combustion products such as water vapor and carbon dioxide, and enters the main flue 13 through the inclined section.

[0054] In the optional embodiments of this example, the preferred embodiment is that the oxygen-enriched supply system 40 has a carbon dioxide inlet and a pure oxygen inlet; the gas purification system 30 has a carbon dioxide outlet, and the carbon dioxide inlet and outlet are connected; the pure oxygen inlet is used to connect to the output port of the pure oxygen supply equipment. The oxygen-enriched supply system 40 uses pure oxygen to assist combustion, reducing the amount of nitrogen in the air participating in the combustion process. In conventional combustion processes, nitrogen and oxygen react at high temperatures to produce nitrogen oxides (NOx), which is one of the air pollutants. However, in an oxygen-enriched combustion environment, due to the reduction of nitrogen, the amount of nitrogen oxides generated is significantly reduced, thus mitigating pollution to the atmospheric environment. By supplying pure oxygen and carbon dioxide to the bottom combustion chamber of the pyrolysis furnace 20, the reaction conditions inside the pyrolysis furnace 20 can be improved, thereby increasing the yield and quality of syngas (carbon monoxide and hydrogen).

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

[0056] Specifically, oxygen-enriched gases mainly consist of carbon dioxide and oxygen, and may also contain water vapor, etc.

[0057] The following are the settings instructions for the gas purification system 30:

[0058] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1As shown, the coal gas purification system 30 includes, in sequence, an ammonia water spraying and condensing device, a gas-liquid separation device 31, a cooling blower 32, a desulfurization device 33, and a decarbonization device 34. Through a series of purification processes, including the ammonia water spraying and condensing device and the gas-liquid separation device 31, impurities such as tar, dust, sulfides, and carbon dioxide in the distillation gas are effectively removed, resulting in high-quality clean coal gas 35. Clean coal gas 35 can be used as a chemical raw material to synthesize high-end chemical products such as methanol and 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 further processing, it can be used to extract various high-value chemical raw materials such as benzene, naphthalene, and phenol for the production of plastics, dyes, pharmaceuticals, and other products, thereby increasing the economic value of the tar.

[0059] Specifically, the ammonia spray condensation equipment, gas-liquid separation equipment 31, cooling blower equipment 32, desulfurization equipment 33, and decarbonization equipment 34 in the gas purification system 30 are all existing equipment and will not be described in detail here. Ammonia spray cooling is used. The ammonia, tar, phenol water, etc. separated by the gas-liquid separation equipment 31 are sent to the ammonia stripping unit, tar processing unit, and wastewater treatment unit for treatment. The cooling blower equipment 32 uses a blower to send gas to the gas desulfurization equipment 33. The desulfurization equipment 33 uses wet desulfurization, and the sulfur paste produced is used for acid production. The decarbonization equipment 34 uses PSA decarbonization, and part of the separated carbon dioxide is used for the gas seal of the coal feeding system of the pyrolysis furnace 20 to prevent air from entering the coal gas system during the coal feeding process, and part of it is used as oxygen-enriched gas to assist combustion in the vertical heat recovery coke oven 10 when mixed with pure oxygen.

[0060] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1As shown, the gas purification system 30 also includes a gas holder 36; the gas discharged from the decarbonized gas outlet of the decarbonization device 34 enters the gas holder 36 through the inlet. The gas pressure inside the gas holder 36 can be adjusted according to actual needs. When gas enters the gas holder 36, the gas holder 36 can absorb excess pressure; when gas flows out of the gas holder 36, it can appropriately increase the pressure. This pressure regulation function allows the gas to undergo combustion or chemical reaction at a suitable pressure during subsequent transportation and use. A suitable pressure helps the gas to burn completely or participate more effectively in chemical synthesis reactions, thereby improving energy utilization efficiency. When the gas is stored in the gas holder 36, some impurities (such as tiny dust particles, trace amounts of incompletely removed sulfides, etc.) may further settle under gravity or undergo adsorption reactions with the inner wall of the gas holder 36, thereby further optimizing the gas quality. High-quality coal gas can release energy or participate in reactions more efficiently when burned or used as a chemical raw material, thus improving energy utilization efficiency. The gas holder 36 can ensure the stability of the coal gas quality and pressure supplied to downstream users. For chemical synthesis enterprises that require high-quality coal gas as raw material, stable coal gas quality is the key to producing high-quality chemical products. The presence of the gas holder 36 makes the allocation of coal gas more flexible. According to market demand and the requirements of different users, the coal gas can be allocated to different uses.

[0061] Among the optional solutions in this embodiment, the more preferred one is as follows: 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. Connecting the carbon dioxide outlet of the gas purification system 30 to the gas sealing device of the coal feeding system of the pyrolysis furnace 20 allows the carbon dioxide to be used for gas sealing. This portion of carbon dioxide, which might otherwise be emitted as waste gas, is now effectively utilized. During the gas sealing process, the carbon dioxide prevents air from entering the coal feeding system of the pyrolysis furnace 20, ensuring a stable reaction atmosphere inside the pyrolysis furnace 20. A stable reaction atmosphere helps the pyrolysis reaction of low-rank coal 21 and other related reactions (such as water-gas reaction) in the pyrolysis furnace 20 to proceed more efficiently, because the entry of air may interfere with the reaction, leading to 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.

[0062] Regarding other related settings:

[0063] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1As shown, the pyrolysis furnace 20 is located on the side of the vertical heat recovery coke oven 10 closest to the coking coal tower 50. This arrangement shortens the distance the low-rank coal 21 needs to travel from the coal tower to the pyrolysis furnace 20. During transport, this reduces energy losses due to long-distance transport, such as the power consumption of belt conveyors. It also reduces the likelihood of heat loss during transport, ensuring that the low-rank coal 21 enters the pyrolysis furnace 20 at a relatively high temperature, thus reducing the energy required for preheating and improving energy efficiency.

[0064] In the optional schemes of this embodiment, it is more preferred that the pyrolysis furnace 20 and the vertical heat recovery coke oven 10 share a single resisting wall. By sharing a single resisting wall, the pyrolysis furnace 20 and the vertical heat recovery coke oven 10 form an integrated structure, making efficient use of space, reducing connecting pipelines, and minimizing heat loss.

[0065] Specifically, a necessary tamping station 51 is also set up at the 50 coking coal towers. This is 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 to the pyrolysis furnace 20.

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

[0068] 1. Existing vertical heat recovery coke ovens use air as the combustion-supporting gas. The high-temperature flue gas discharged from these ovens is mostly nitrogen, water vapor, carbon dioxide, and a small amount of unburned hydrogen and carbon monoxide. Each ton of coking coal can produce approximately 400 cubic meters of raw coal gas. Combustion of 40% is sufficient to meet the heat requirements of the coking process. The remaining 60% of the combustible gas needs to be supplemented and converted into heat before being 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, resulting in energy waste. This coupled system uses oxygen-enriched gas as the combustion-supporting gas and couples the heat recovery coke oven with the pyrolysis furnace to fully utilize their respective advantages and achieve a synergistic effect greater than the sum of its parts.

[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 in the low-rank coal pyrolysis furnace. The heat 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℃, which is suitable for the pyrolysis of low-rank coal. At the same time, some of the water vapor and carbon dioxide in the high-temperature flue gas are converted into hydrogen and carbon monoxide, which reduces carbon emissions and increases the content of combustible gases in the flue gas.

[0070] 3. Low-rank coal pyrolysis is carried out 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 increasing the yield of medium-temperature tar in the pyrolysis products, 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, resulting in good economic benefits.

[0072] 5. The heat recovery coke oven is coupled with low-rank coal pyrolysis, and the whole system adopts a 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, which greatly reduces the production water consumption and is suitable for arid and water-scarce areas.

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

[0076] 9. When oxygen-enriched gas is used as the combustion-supporting gas for heat recovery coke ovens, the carbon dioxide separated from the pyrolysis gas is mixed with pure oxygen, which improves the thermal efficiency of the heat recovery coke ovens. The high-temperature flue gas does not contain nitrogen, and the content of residual combustible gas in the coke oven flue gas increases. The proportion of water vapor and carbon dioxide increases, which is beneficial for these gases to serve as gasification gases and pyrolysis carrier gases in the pyrolysis furnace. This is beneficial for the gasification reaction of semi-coke and the pyrolysis of low-rank coal, and further improves the quality of pyrolysis gas and oil products.

[0077] 10. The heat recovery coke oven coupled with low-rank coal pyrolysis expands the scope of coal resource utilization (coking coal + low-rank coal), increases product variety (coke + activated semi-coke + clean coal gas + light oil + electricity), and enhances the project's market competitiveness and flexibility.

[0078] 11. Low-rank coal pyrolysis furnaces include internal heating and external heating types, and their structural forms include vertical moving bed and rotary furnace types.

[0079] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology, characterized in that: This includes 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 in a water-gas reaction; the high-temperature flue gas can absorb heat through the water-gas reaction to form medium-temperature flue gas, which is used to pyrolyze the low-rank coal in the pyrolysis furnace to produce product semi-coke and dry distillation gas. The product semi-coke falls in the pyrolysis furnace under the action of gravity and can react with the high-temperature flue gas below in a water-gas reaction. The top outlet of the pyrolysis furnace is connected to the inlet of the gas purification system, which is used to purify the incoming gas, and the outlet of the gas purification system produces clean gas and medium-low temperature tar. The oxygen-enriched supply system is capable of supplying oxygen-enriched gas, which is connected to the bottom combustion chamber of the pyrolysis furnace via an oxygen-enriched supply pipeline.

2. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1, characterized in that: The oxygen-enriched supply system has a carbon dioxide inlet and a pure oxygen inlet; The 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 connect to 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, characterized in that: The oxygen-enriched gas is connected to each combustion chamber of the vertical heat recovery coke oven through the coke oven combustion gas channel.

4. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 2, characterized in that: The carbon dioxide outlet is connected to the gas sealing device of the coal feeding 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, characterized in that: The bottom of the pyrolysis furnace has a semi-coke outlet, and a gate is provided at the semi-coke outlet, which can change the opening degree of the semi-coke outlet.

6. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1, characterized in that: The gas purification system includes, in sequence, an ammonia spray condensation device, a gas-liquid separation device, a cooling blower, a desulfurization device, and a decarbonization device.

7. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 6, characterized in that: The gas purification system also includes a gas holder; the gas discharged from the decarbonized 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, characterized in that: The oxygen concentration in the oxygen-enriched gas is below 30%.

9. The coupling system of heat recovery coke oven technology and low-rank coal pyrolysis technology according to claim 1, characterized in that: The pyrolysis furnace is located on the side of the vertical heat recovery coke oven near the coking coal tower.

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

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