Carbonization furnace with double return air passages

Abstract

The utility model belongs to the field of carbonization furnaces, and provides a carbonization furnace with double furnace return air passages, which aims to solve the problems of air passage ignition, influence on production load, gas backflow and possible flash explosion in the traditional carbonization furnace structure process, and comprises a furnace body, and a cavity in the furnace body is a carbonization chamber. The lower part of the carbonization chamber is divided into a plurality of mutually independent coke discharge ports by partition walls; an upper gas passage and a lower gas passage which are independent are respectively arranged on the partition wall and the inner wall of the furnace body corresponding to the partition wall in height, a plurality of fire holes communicated with the carbonization chamber are respectively formed in the gas passages, the gas passages comprise an air passage and a gas passage, and the air passage is arranged above the gas passage in parallel. According to the utility model, returned coal gas and returned air respectively enter the carbonization furnace from the two independent air passages, so that the problems that mixed gas of air and coal gas exists in the air passages, a lattice wall is easily burnt out, or flash explosion is caused in a pipeline and the like are solved, the temperature in the carbonization furnace can be conveniently and automatically controlled and adjusted, and the heat utilization efficiency is improved.

Description

Technical Field

[0001] This utility model belongs to the field of carbonization furnaces, specifically relating to a carbonization furnace with a double return gas passage. Background Technology

[0002] Coal dry distillation is the process by which coal decomposes under air-isolated conditions to produce coal gas, tar, crude benzene, and coke. It is also called coal pyrolysis or coal coking. Based on the final heating temperature, coal dry distillation can be divided into three types: low-temperature dry distillation, medium-temperature dry distillation, and high-temperature dry distillation. Low-temperature coal dry distillation commonly uses internally heated carbonization furnaces (also known as semi-coke furnaces or pyrolysis furnaces), primarily to extract coal tar, with byproducts including raw coal gas and semi-coke (or upgraded coal).

[0003] The current carbonization furnace process involves recycled coal gas and air entering the gas duct (also known as the fire channel) through burners, forming a mixed gas. This mixture then enters the carbonization chamber, where it is burned, using the heat to heat the raw coal for dry distillation. The problems with this process are: the mixed gas in the gas duct makes it highly susceptible to ignition, burning down the heat exchanger wall, reducing the heat entering the carbonization chamber, and impacting the furnace's production capacity. Gas duct ignition easily damages the heat exchanger wall, shortening the furnace's lifespan and increasing major repair costs. Furthermore, during start-up and shutdown, the mixed gas can easily flow back into the recycled coal gas or air pipelines, causing flash explosions and posing a significant safety risk. To prevent ignition in the gas duct, the gas-air mixing ratio needs to be increased during production, requiring regular checks and adjustments, which is difficult and hinders production capacity. Summary of the Invention

[0004] To address the problems of gas ignition, reduced production load, gas backflow, and potential flash explosions in traditional carbonization furnace structures, this invention provides a carbonization furnace with a double-return gas duct.

[0005] This utility model provides a carbonization furnace with a double-return gas duct, which adopts the following technical solution:

[0006] A carbonization furnace with a double-return gas duct includes a furnace body, the interior cavity of which is a carbonization chamber. The lower part of the carbonization chamber is divided into several independent coke discharge ports by a partition wall (or decorative wall). The partition wall and the inner wall of the furnace body at the corresponding height of the partition wall are provided with two independent upper and lower gas ducts. Several fire holes connected to the carbonization chamber are opened on the gas ducts.

[0007] By adopting the above technical solution, air and gas are designed to be delivered through two independent gas ducts, ensuring that there is no more mixed gas in the gas ducts.

[0008] Furthermore, the gas duct includes an air duct and a gas duct, with the air duct arranged parallel above the gas duct.

[0009] Because the amount of recycled gas relative to the amount of recycled air is excessive, adjusting the gas-to-air ratio can regulate the temperature of the carbonization furnace. Generally, a gas-to-air ratio controlled between 1.8 and 2.2 is suitable for the carbonization furnace's dry distillation temperature, meaning combustion in the carbonization furnace occurs under oxygen-deficient conditions. Therefore, by adopting the above technical solution, the gas duct is positioned at the bottom, allowing the gas to rise and absorb heat before burning upon encountering air entering through the air duct. Conversely, if the air duct is positioned at the bottom, the incoming air will first burn with the descending semi-coke.

[0010] Furthermore, the carbonization chamber includes a preheating section, a dry distillation section, and a cooling section from top to bottom, with the air duct and gas duct located in the cooling section.

[0011] By adopting the above technical solution, the air enters the carbonization chamber through the flame and begins to burn. The high-temperature airflow generated by the combustion rises and heats the coal for dry distillation.

[0012] Furthermore, the air duct and the gas duct are respectively provided with two rows of flame holes, one above the other, and the opening of the flame holes is inclined downwards.

[0013] By adopting the above technical solution, the downward-sloping flame hole can ensure that gas and air can effectively enter the carbonization chamber, while effectively preventing coal or semi-coke produced from entering the gas passage, blocking or damaging the gas passage wall, or even causing an explosion.

[0014] An air nozzle is installed at the inlet of the air duct, and a gas nozzle is installed at the inlet of the gas duct. The air nozzle and gas nozzle have the same structure, including a hollow nozzle body. The front of the nozzle body has an air outlet, and the rear of the nozzle body has an air inlet. The air outlet has a constricted design and is equipped with guide vanes. The guide vanes are arranged in a circular array and are inclined relative to the central axis of the nozzle body. The air inlet is connected to an external delivery pipeline network via a control valve.

[0015] By adopting the above technical solution, the delivery of air and gas can be effectively controlled separately using independently installed air nozzles and gas nozzles. The air outlet features a constricted design, meaning its diameter is smaller than the nozzle body's diameter, which increases the pressure of the gas entering the gas passage. The guide vanes at the air outlet effectively ensure uniform gas distribution within the gas passage.

[0016] The tail of the nozzle body is also provided with a sight glass and a purge port. The sight glass can be used to observe the internal operation of the nozzle or air passage, and the purge port is used for purging and replacing the nozzle or air passage.

[0017] The furnace body is constructed using clay bricks and high-alumina bricks, and the partition wall is constructed using high-alumina bricks.

[0018] By adopting the above technical solution, both clay bricks and high-alumina bricks are refractory bricks, with high-alumina bricks having a higher refractory rating. Therefore, high-alumina bricks are used in the high-temperature areas inside the furnace (partition walls and the inner walls of the furnace within the corresponding height range of the partition walls), effectively ensuring the service life of the carbonization furnace.

[0019] In summary, this utility model has at least one of the following beneficial technical effects:

[0020] 1. The return gas and air enter the carbonization furnace separately, and there is no longer a mixed gas inside the gas duct. This avoids the mixed gas inside the gas duct from igniting and burning the flower wall, and solves the problem of frequent shutdowns for flower wall maintenance due to damage.

[0021] 2. Solved the problems of gas leakage and backfire that easily occur when the recycled gas and air enter the gas passage through the same burner, as well as the problem of flash explosion in the pipeline when gas flows back into the recycled gas pipeline and air pipeline;

[0022] 3. The return gas and air enter the carbonization furnace separately, which makes it easier to regulate the temperature and load of the carbonization furnace. It also eliminates the need for frequent checks on the gas duct ignition and facilitates automatic control of the carbonization furnace.

[0023] 4. The recycled gas enters from the bottom and then rises, making countercurrent contact with the high-temperature semi-coke moving downwards. This lowers the temperature of the semi-coke, raises the temperature of the recycled gas, and improves the heat utilization efficiency. Attached Figure Description

[0024] Figure 1 This is a front sectional view of the carbonization furnace of this utility model;

[0025] Figure 2 for Figure 1 AA half-section view in the middle;

[0026] Figure 3 This is a schematic diagram of the air nozzle structure;

[0027] Figure 4 This is a schematic diagram of the arrangement of the guide vanes;

[0028] In the diagram: 1-furnace body; 2-carbonization chamber; 3-partition wall; 4-air duct; 5-gas duct; 6-coke discharge port; 7-fire hole; 8-air nozzle; 9-gas nozzle;

[0029] 101-Air inlet; 102-Sight glass; 103-Purge port; 104-Nozzle body; 105-Air outlet; 106-Guide vane. Detailed Implementation

[0030] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0031] like Figure 1 and 2 The carbonization furnace shown has a carbonization chamber 2 inside the furnace body 1. The lower part of the carbonization chamber 2 is divided into several independent coke discharge ports 6 by a partition wall 3. The partition wall 3 and the inner wall of the furnace body 1 at the corresponding height are each provided with two independent upper and lower gas channels. Each gas channel has multiple burners 7 connected to the carbonization chamber 2. The gas channels include an air channel 4 and a gas channel 5, with the air channel 4 arranged parallel above the gas channel 5. Two rows of burners 7 are provided on the air channel 4 and the gas channel 5, respectively. The partition wall 3 and the inner wall of the furnace body at the corresponding height are high-temperature zones, therefore they are constructed using high-alumina bricks with strong refractory properties. The rest of the main body of the furnace body 1 is constructed using clay bricks. Both the high-alumina bricks and the clay bricks are heat-resistant bricks.

[0032] The recycled gas and air enter the carbonization furnace separately. The recycled gas is supplied through the lower gas duct 5, and air is supplied through the upper air duct 4, eliminating the problem of mixed gases. At the same time, the burners used in the original carbonization furnace are modified to eliminate burners that mix air and gas. An air nozzle 8 is installed at the inlet of the air duct 4, and a gas nozzle 9 is installed at the inlet of the gas duct 5.

[0033] Air nozzle 8 and gas nozzle 9 have the same structure, as detailed below. Figure 3 As shown, the nozzle body 104 is hollow and includes an air inlet 101, a sight glass 102, a purge port 103, an air outlet 105, and guide vanes 106. The air inlet 101 is connected to an external gas supply network via a control valve to introduce recycled coal gas and air, which are then sent into the corresponding gas duct through the air outlet 105.

[0034] The nozzle is designed with a sight glass 102 to observe the internal operation of the nozzle or airway; the nozzle is designed with a purge port 103 for purging and replacing the nozzle or airway; the outlet 105 of the nozzle is narrowed to increase the pressure of the gas entering the airway; the outlet 105 of the nozzle is equipped with a guide vane 106 to ensure uniform gas distribution in the airway.

[0035] The circumferential arrangement of the guide vanes 106 is as follows Figure 4 As shown, four sets of ring arrays are evenly distributed, and the guide vanes 106 are inclined at 20° relative to the central axis of the nozzle body 104.

[0036] The working principle of this carbonization furnace is as follows:

[0037] Raw coal enters the carbonization chamber from the top of the carbonization furnace, moves downwards inside the chamber, and comes into countercurrent contact with the high-temperature gas rising from the combustion chamber, heating and dry distilling the coal to produce semi-coke and raw coal gas. The semi-coke is discharged through the coke outlet at the bottom of the carbonization furnace.

[0038] The raw coal gas is drawn from the top of the carbonization furnace, and after passing through the cooling and purification device, it is pressurized by the gas blower and enters the main gas outlet pipe. After the gas-liquid separator separates the condensate in the coal gas, part of it is sent to the carbonization furnace of this utility model as recycled coal gas, and enters the carbonization furnace for combustion through the gas nozzle and gas passage. The other part is sent to the external pipeline network for use by other devices.

[0039] Each coke discharge port at the bottom of the carbonization chamber is separated by a partition wall. Inside the partition wall are upper air ducts and lower gas ducts. Each duct is equipped with a nozzle. Return gas and air enter the corresponding duct through the nozzle, and then pass through the return gas duct and return air duct respectively before entering the carbonization chamber through the flame hole in the partition wall. Combustion occurs in the carbonization chamber, and the high-temperature airflow generated by combustion rises and comes into countercurrent contact with the downward-moving raw coal, heating and dry distilling the coal.

[0040] This invention introduces recycled coal gas and recycled air into the carbonization furnace through two separate gas ducts, avoiding problems such as fire and damage to the decorative wall or flash explosion caused by the mixture of air and coal gas in the gas ducts. Furthermore, the separate entry of recycled coal gas and recycled air into the carbonization furnace through two separate gas ducts facilitates automatic control and regulation of the furnace temperature, thereby improving heat utilization efficiency.

[0041] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A carbonization furnace with a double-return gas duct, comprising a furnace body (1), wherein the internal cavity of the furnace body (1) is a carbonization chamber (2), characterized in that: The lower part of the carbonization chamber (2) is divided into several independent coke discharge ports (6) by a partition wall (3); the partition wall (3) and the inner wall of the furnace body (1) at the corresponding height of the partition wall (3) are provided with two independent gas channels, one above the other, and several fire holes (7) connected to the carbonization chamber (2) are opened on the gas channels.

2. The carbonization furnace with a double-return gas duct according to claim 1, characterized in that, The air passage includes an air passage (4) and a gas passage (5), with the air passage (4) arranged parallel above the gas passage (5).

3. A carbonization furnace with a double-return gas duct according to claim 2, characterized in that, The carbonization chamber (2) includes a preheating section, a dry distillation section and a cooling section from top to bottom, and the air duct (4) and the gas duct (5) are located in the cooling section.

4. A carbonization furnace with a double-return gas duct according to claim 2, characterized in that, The air duct (4) and the gas duct (5) are respectively provided with two rows of fire holes (7), and the opening of the fire hole (7) is set at an angle downward.

5. A carbonization furnace with a double-return gas duct according to claim 2, characterized in that, An air nozzle (8) is installed at the inlet of the air duct (4), and a gas nozzle (9) is installed at the inlet of the gas duct (5).

6. A carbonization furnace with a double-return gas duct according to claim 5, characterized in that, The air nozzle (8) and the gas nozzle (9) have the same structure, including a hollow nozzle body (104). The front of the nozzle body (104) is provided with an air outlet (105), and the rear of the nozzle body (104) is provided with an air inlet (101). The air outlet (105) is a constricted design, and a guide vane (106) is provided at the air outlet (105).

7. A carbonization furnace with a double-return gas duct according to claim 6, characterized in that, The guide vanes (106) are arranged in a ring array, and the guide vanes (106) are inclined relative to the central axis of the nozzle body (104).

8. A carbonization furnace with a double-return gas duct according to claim 6, characterized in that, The tail of the nozzle body (104) is also provided with a sight glass (102) and a purge port (103).

9. A carbonization furnace with a double-return gas duct according to claim 1, characterized in that, The furnace body (1) is constructed of clay bricks and high-alumina bricks, and the partition wall (3) is constructed of high-alumina bricks.

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