WO2024223016A1 - Apparatus for producing coke and method of operating same - Google Patents

Abstract

The proposed invention relates to a shaft furnace for producing coke, including high-temperature coke, and includes an apparatus for producing coke and a method of operating same. The apparatus for producing coke comprises a shaft furnace having a housing, a coke discharge hatch disposed in the bottom part of the housing, and a cover disposed in the top part of the housing. The cover comprises nozzles adapted to deliver water into the housing of the shaft furnace. The nozzles are grouped into at least two groups: a first group and a second group, each of which is adapted for the delivery of water thereto independently of the other group. The groups of nozzles are arranged around the centre of the cover in such a way that the distance from the centre of the cover to any one of the nozzles of the first group is greater than the distance from the centre of the cover to any one of the nozzles of the second group. The technical result of the claimed invention consists in producing high-strength coke by making it possible to gradually lower the temperature of the coke and relieve thermal stress without causing thermal shocks and material damage, while at the same time increasing the operating reliability of the apparatus using a simple and compact design, saving water and preventing overwetting of the coke by virtue of the metered selective delivery of water to different areas of the housing of the shaft furnace.

Description

COKE PRODUCING PLANT AND ITS OPERATING METHOD

Field of technology

The proposed invention relates to a shaft furnace for producing coke, including high-temperature coke.

State of the art

From the Eurasian patent for invention EA011685, published on 28.04.2009, a shaft furnace is known, comprising a housing, a hatch for unloading coke, located in the lower part of the housing, a cover, located in the upper part of the housing, temperature sensors and an air flow regulator. When a signal is received from the lower temperature sensor about the combustion front reaching the grate, the air supply is automatically stopped.

The disadvantage of this invention is the absence of a built-in coke extinguishing device, as well as the lack of the ability to automatically activate the coke extinguishing device after stopping the air supply, which leads to a complication of the hardware design and a decrease in its reliability.

From the Chinese patent CN103980914B, published on 25. P. 2015, a device for extinguishing the product of pyrolysis of brown coal with a rotating bottom is known, comprising a rotating bottom body, including a lower rotating shaft and an upper fixed furnace cover. Three nozzles (11, 12, 13) of the first group and three nozzles (21, 22, 23) of the second group are located along a circle of 2.3 m from the center of the furnace cover. Two nozzles (14, 15) and two nozzles (24, 25) of the second group are located along a circle of 1.2 m from the center of the furnace cover 12; the third group of nozzles 4 (31, 32, 33, 34) is located along a circle of 2.3 m from the center of the furnace cover 12. The first group of nozzles and the second group of nozzles are the main spray nozzles, the third group of nozzles is auxiliary.

The disadvantage of this invention is the low strength of the resulting coke due to the fact that the location and order of activation of the groups of nozzles for supplying water does not take into account the features of relieving thermal stresses without thermal shocks and destruction of the material, which leads to a decrease in the strength of the resulting coke.

From the Chinese patent CN103980915B, published on 25.11.2015, a device for extinguishing the product of pyrolysis of brown coal is known, comprising a converter (retort) with an upper furnace cover and a rotating bottom connected to the furnace cover. A plurality of sets of nozzles for spraying water are located inside the converter, forming the first group of injectors 11-15, the second group of injectors 21-25, and the third group of injectors 31-34.

The disadvantage of this invention is the low strength of the resulting coke due to the fact that the location and order of activation of the groups of nozzles for supplying water does not take into account the features of relieving thermal stresses without thermal shocks and destruction of the material, which leads to a decrease in the strength of the resulting coke.

Disclosure of the essence of the invention

The objective of the present invention and the technical result of the claimed invention are to obtain high-strength coke by ensuring a smooth reduction in the temperature of the coke and the removal of thermal stresses without thermal shocks and destruction of the material, increasing the reliability of the plant by using simple and compact hardware, saving water and eliminating over-moistening of the coke due to the metered selective supply of water to various zones of the shaft furnace body, as well as increasing the specific productivity of the plant.

In order to solve the above-mentioned problem and achieve the technical result, a coke production plant is proposed, including a shaft furnace containing a housing, a hatch for unloading coke, located in the lower part of the housing, a cover located in the upper part of the housing, wherein the cover contains nozzles made with the possibility of feeding water through them into the shaft furnace housing, the nozzles are combined into at least two groups of nozzles: a first group and a second group, each of which is made with the possibility of feeding water into it independently of the other group, characterized in that said groups of nozzles are located around the center of the cover in such a way that the distance from the center of the cover to any of the nozzles of the first group is greater than the distance from the center of the cover to any of the nozzles of the second group.

The above division of the nozzles into groups allows the formation of several circuits for the supply of water for quenching coke, which can be activated in the direction from the periphery to the center, which allows for the removal of thermal stress, reducing the risk of thermal shock and destruction of the material, which leads to an increase in the strength of the resulting coke.

During the operation of shaft furnaces (coke retorts), we found that the temperature is distributed unevenly across the shaft furnace cross-section - the central region, occupying about 25% of the cross-sectional area, has the highest temperature, which gradually decreases towards the periphery. The temperature difference between the center and the wall region can reach 200-400°C. Supplying water directly to the central zone, heated to over 1000°C, will inevitably lead to a sharp thermal shock and a decrease in the strength of the coke due to the formation of microcracks. Therefore, quenching should begin with the peripheral region, which has a temperature of 600-700°C. In this case, the resulting steam moves under pressure from the periphery to the central part of the furnace, where it is additionally heated in the hot zone (i.e. removes part of the heat) and leaves the furnace through the flue. Accordingly, by the start of water supply through the second group of nozzles (second circuit), the temperature in the central zone decreases to acceptable values, which reduces the likelihood of thermal shock when water enters.

Preferably, the nozzles are combined into at least three groups of nozzles: a first group, a second group and a third group, each of which is designed with the possibility of supplying water to it independently of the other group, wherein said groups of nozzles are located around the center of the lid in such a way that the distance from the center of the lid to any of the nozzles of the first group is greater than the distance from the center of the lid to any of the nozzles of the second group, and the distance from the center of the lid to any of the nozzles of the second group is greater than the distance from the center of the lid to any of the nozzles of the third group.

Preferably, the ratio between the distance from the center of the cover to any of the first group nozzles and the distance from the center of the cover to any of the second group nozzles is 1.4-2; the ratio between the distance from the center of the cover to any of the first group nozzles and the distance from the center of the cover to any of the third group nozzles is 2.2-5; the ratio between the distance from the center of the cover to any of the second group nozzles and the distance from the center of the cover to any of the third group nozzles is 1.4-3.2.

Preferably, each group of nozzles is connected to a water supply system designed so that the water supply is carried out in the form of at least one a water supply cycle in which water is supplied sequentially to each group of nozzles, starting with the first group of nozzles, so that each subsequent group of nozzles has a distance from the center of the cover to any of the nozzles of this group that is less than the previous group of nozzles.

Preferably, the supply system is configured to supply a given amount of water to each group of nozzles in one cycle.

Preferably, the water supply system is designed such that the water supply cycle can be repeated a specified number of times.

Due to the metered selective supply of water to different zones of the furnace, water savings are ensured and coke does not become over-moistened.

Combining nozzles into at least three groups (circuits) with independent water supply allows for a smooth reduction in coke temperature and thermal stress relief without thermal shocks and material destruction, which allows for improved thermal stress relief, further reducing the risk of thermal shocks and material destruction, which leads to an even greater increase in the strength of the resulting coke. A larger number of groups (circuits) of nozzles is also possible for an even smoother reduction in coke temperature, however, since the cost of the furnace will increase with an increase in the number of circuits, the exact number of circuits should be selected depending on the size of the furnace, taking into account the optimal coke cooling profile.

The ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the second group is 1.4-2; the ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the third group is 2.2-5; the ratio between the distance from the center of the cover to any of the nozzles of the second group and the distance from the center of the cover to any of the nozzles of the third group is 1.4-3.2, which allows for the smoothest reduction in coke temperature and an even greater increase in the strength of the resulting coke.

Preferably, the shaft furnace body is equipped in the lower part with at least one temperature sensor configured to transmit a signal for starting a water supply cycle.

Preferably, the shaft furnace is equipped with a blast fan, and the temperature sensor in the lower part of the shaft furnace body is designed with the possibility transmitting a signal to stop the blower fan and then start the water supply cycle.

Preferably, the installation is equipped with at least one temperature sensor configured to measure the temperature of the steam-gas mixture formed when water is supplied to the shaft furnace body and to transmit a signal for terminating the water supply cycle.

The presence of sensors that enable the activation of water supply to the shaft furnace depending on the temperature of the steam-gas mixture formed when water is supplied to the shaft furnace body, and stop the operation of the blast fan depending on the temperature in the lower part of the furnace allows more precise regulation of the operation of the furnace components, ensuring energy and water savings.

Preferably, the installation is mobile or stationary.

Preferably, the body comprises an upper part and a lower part, wherein the upper part has a substantially cylindrical shape, and the lower part has a substantially truncated cone shape, wherein the ratio of the height of the upper part to the total height of the body is 0.25-0.31; the ratio of the diameter of the upper part to the total height of the body is 0.55-0.63.

This allows for a more uniform movement of the combustion front, ensuring an increase in the specific productivity of the plant. In this case, the share of time spent on intermediate operations (quenching and unloading coke, cooling and preparing the furnace, loading raw materials and ignition) in the total duration of the furnace operation cycle is reduced.

Preferably, the lower part comprises a horizontal gas distribution ring arranged in such a way that at least part of the supplied air coming from the blower fan can be directed underneath it.

This allows for a more uniform air flow across the entire furnace area, which helps to increase the synchronicity and speed of the combustion front, ensuring an increase in the specific productivity of the unit. Uniform air distribution in the furnace volume with increased blast flow allows for an increase in the coking temperature in the combustion front, as well as the heating rate of the coal, which helps to improve the quality of the coke in terms of volatile content and structural strength. At the same time, the loss of solid carbon associated with its burn-off is significantly reduced, and the yield of suitable coke increases relative to the mass of the original coal. Preferably, the lower part is designed with the possibility of loading into it a layer of screened coke of fraction 20-40 mm.

This ensures protection of the device's structural elements from heating.

Also, to solve the above-mentioned problem and achieve the technical result, a method of operating the above-mentioned installation for producing coke is proposed, in which the water supply is carried out in the form of at least one water supply cycle, in which the water supply is carried out sequentially into each group of nozzles, starting with the first group of nozzles, so that each subsequent group of nozzles has a distance from the center of the cover to any of the nozzles of this group that is smaller than the previous group of nozzles.

Preferably, a given amount of water is supplied to each group of nozzles in one cycle.

Preferably, the water supply cycle is started based on a signal received from a temperature sensor located in the lower part of the shaft furnace body.

Preferably, based on a signal received from a temperature sensor located in the lower part of the shaft furnace body, the blast fan with which the shaft furnace is equipped is switched off before the start of the water supply cycle.

Preferably, the water supply cycle is terminated based on a signal received from a temperature sensor located in the upper part of the shaft furnace body.

Brief description of the drawings

The drawings are presented for a better understanding of the invention, however, it will be obvious to a person skilled in the art that the disclosed invention is not limited to the embodiment shown therein.

Fig. 1 shows a schematic view of an installation for producing coke in accordance with the present description of the invention.

Fig. 2 shows a schematic view of the lid of the coke production plant, with three groups (circuits) of nozzles in accordance with the present description of the invention.

Implementation of the invention Fig. 1 shows an installation for producing coke 1, including a shaft furnace 2, containing a brick-lined body 3, a hatch 4 for unloading coke, located in the lower part of the body 3, and a cover 5, located in the upper part of the body 3.

Fig. 2 shows a cover 5, which contains nozzles 6, designed with the possibility of supplying water through them into the body 3 of the shaft furnace.

The nozzles 6 are combined into three groups (circuits) of nozzles: the first group 7, the second group 8 and the third group 9, each of which is designed with the possibility of supplying water to it independently of the other group.

Groups 7, 8 and 9 of nozzles are arranged around the center of cover 5 in such a way that the distance from the center of the cover to any of the nozzles of the first group is greater than the distance from the center of the cover to any of the nozzles of the second group.

The above-mentioned placement of the nozzles allows for the gradual cooling of coke in the direction from the periphery to the center of the cover: first, water is supplied to the peripheral zone, then the middle, then the central zone.

In Fig. 2, groups 7, 8 and 9 are arranged in the form of concentric circles, however, it is clear to a person skilled in the art that they can be arranged in any way to meet the above requirement, for example, in the form of squares, polygons, a spiral, a zigzag, a wave, and so on.

The installation works as follows.

Raw material (coal) is fed into shaft furnace 2 through loading hatch 10, leaving free space.

An ignition mixture (coke fines of 0-10 mm fraction, soaked in diesel fuel) is loaded on top of the coal evenly across the cross-section of the furnace.

Ignition is carried out by turning on the blower fan (not shown), opening the guillotine damper (not shown) on the flue (not shown), turning on the gas burner in the spark plug and igniting the ignition mixture, and closing the loading hatch cover.

Pyrolysis. By adjusting the blast flow rate using the rotary damper of the air duct 12, the required temperature in the combustion zone is set (1000-1100°C).

Temperature control is carried out using thermocouples of the XA type (chromel-alumel), the measurement limit is from 0 to 1200°C. Thermocouples in quantities of at least 5 pieces are installed along the entire height of the furnace at uniform intervals. During the process, the temperature and speed of movement of the combustion zone are monitored, which under normal conditions should be 1.6-2.0 cm/min.

The afterburner is a horizontal lined steel cylinder connected to a brick chimney for the release of exhaust gas. The height of the chimney is selected in such a way as to provide sufficient natural draft and create a vacuum in the furnace, flue and candle, eliminating the leakage of coking products. From the receiving end, flues from coke ovens are cut into the candle. The places where the flues are cut in are equipped with gas burners for igniting the gas-air mixture. The receiving end of the candle has holes through which air enters the candle to ensure combustion of the gases.

Coke gas 13 from the furnace enters the afterburner candle 14, where it mixes with air and burns in the candle volume. The resulting gas 15, consisting mainly of carbon dioxide, nitrogen and water vapor, is released into the atmosphere through the smoke stack 16.

Upon completion of the coking process and the combustion front reaching the lower part of the furnace (in the area where the conical and cylindrical parts of the furnace meet), the signal from the lower thermocouple (temperature sensor) of the furnace automatically switches off the blower fan and, via the pulse counter, gives the command to the water supply system to open the water valve of the first group of 7 nozzles (first circuit), through which 3200-4800 liters of water are supplied to the furnace, i.e. from 200 to 300 liters per nozzle.

Upon reaching the specified water flow rate, the valve of the first group of 7 nozzles (first circuit) automatically closes and the valve of the second group of 8 nozzles (second circuit) opens, through which water is also supplied at a flow rate of 200-300 liters per nozzle. Thus, 1600-2400 liters of water are supplied from the second circuit to the furnace, after which the valve of the second group of 8 nozzles (second circuit) closes. Then the valve of the third group of 9 nozzles (third circuit, central circuit) opens, through which another 800-1200 liters of water are supplied to the furnace. After closing the valve of the third group of 9 nozzles, the cycle is repeated.

Thus, the control unit alternately supplies water to the furnace through the first, second and third circuits with the same flow rate for each nozzle. The water flow rate for each circuit is set by the operator and depends on the coking temperature, the temperature in the coke layer, the type and properties of the coal used and other factors. The ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the second group is 1.4-2; the ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the third group is 2.2-5; the ratio between the distance from the center of the cover to any of the nozzles of the second group and the distance from the center of the cover to any of the nozzles of the third group is 1.4-3.2. This allows for the smoothest reduction in coke temperature and an even greater increase in the strength of the resulting coke.

The thermocouple (temperature sensor) of the extinguishing system is installed in the furnace flue pipe in its upper part to control the temperature of the outgoing steam-gas mixture. When the steam temperature drops to 200°C, the signal from the TRM1 measuring and controller is sent to the control unit. Extinguishing stops, all water valves close and the light and sound alarm is turned on, indicating the end of the extinguishing process.

After the fire has finished quenching, you can begin unloading the coke from the furnace.

Coke leaves the oven at a temperature of 150-180°C and enters the vibrating tray 11, irrigated with water, for final cooling to a temperature no higher than 100°C.

The resulting coke has a structural strength of at least 82.7%, the specific productivity of the plant is at least 52 kg/( ^m2 - h) and the coke yield is at least 60% of the mass of the original coal.

The described embodiment examples are given solely for illustrative purposes. It will be obvious to a specialist that other embodiments are possible without changing the essence of the invention.

Claims

Invention formula 1. An installation for producing coke, including a shaft furnace containing a housing, a hatch for unloading coke, located in the lower part of the housing, a cover located in the upper part of the housing, wherein the cover contains nozzles configured to supply water through them into the housing of the shaft furnace, the nozzles are combined into at least two groups of nozzles: a first group and a second group, each of which is configured to supply water to it independently of the other group, characterized in that said groups of nozzles are located around the center of the cover in such a way that the distance from the center of the cover to any of the nozzles of the first group is greater than the distance from the center of the cover to any of the nozzles of the second group. 2. The installation according to item 1, characterized in that the nozzles are combined into at least three groups of nozzles: the first group, the second group and the third group, each of which is designed with the possibility of supplying water to it independently of the other group, and the said groups of nozzles are located around the center of the lid in such a way that the distance from the center of the lid to any of the nozzles of the first group is greater than the distance from the center of the lid to any of the nozzles of the second group, and the distance from the center of the lid to any of the nozzles of the second group is greater than the distance from the center of the lid to any of the nozzles of the third group. 3. The installation according to item 2, characterized in that the ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the second group is 1.4-2; the ratio between the distance from the center of the cover to any of the nozzles of the first group and the distance from the center of the cover to any of the nozzles of the third group is 2.2-5; the ratio between the distance from the center of the cover to any of the nozzles of the second group and the distance from the center of the cover to any of the nozzles of the third group is 1.4-3.2. 4. An installation according to any of paragraphs 1-3, characterized in that each group of nozzles is connected to a water supply system designed so that the water supply was carried out in the form of at least one water supply cycle, in which water is supplied sequentially to each group of nozzles, starting with the first group of nozzles, in such a way that each subsequent group of nozzles has a distance from the center of the cover to any of the nozzles of this group that is less than the previous group of nozzles. 5. The installation according to item 4, characterized in that the supply system is designed with the possibility of supplying a specified amount of water to each group of nozzles in one cycle. 6. The installation according to item 4, characterized in that the water supply system is designed in such a way that the water supply cycle can be repeated a specified number of times. 7. The installation according to item 4, characterized in that the shaft furnace body in the lower part is equipped with at least one temperature sensor, designed with the possibility of transmitting a signal for starting the water supply cycle. 8. The installation according to item 7, characterized in that the shaft furnace is equipped with a blast fan, and the temperature sensor in the lower part of the shaft furnace body is designed with the possibility of transmitting a signal to stop the operation of the blast fan and then start the water supply cycle. 9. The installation according to item 4, characterized in that the installation is equipped with at least one temperature sensor, designed with the possibility of measuring the temperature of the steam-gas mixture formed when water is supplied to the shaft furnace body, and transmitting a signal for ending the water supply cycle. 10. An installation according to any of paragraphs 1-3, characterized in that the installation is mobile or stationary. 11. The installation according to claim 8, characterized in that the housing comprises an upper part and a lower part, wherein the upper part has a substantially cylindrical shape, and the lower part has a substantially truncated cone shape, wherein the ratio of the height of the upper part to the total height of the housing is 0.25-0.31; the ratio of the diameter of the upper part to the total height of the housing is 0.55-0.63. 12. The installation according to item 11, characterized in that the lower part contains a horizontal gas distribution ring, positioned in such a way that at least part of the supplied air coming from the blower fan can be directed under it. 13. The installation according to item 11, characterized in that the lower part is designed with the possibility of loading into it a layer of screened coke of fraction 20-40 mm. 14. A method of operating a coke production plant according to any of paragraphs 1-13, in which the water supply is carried out in the form of at least one water supply cycle, in which the water supply is carried out sequentially into each group of nozzles, starting with the first group of nozzles, so that each subsequent group of nozzles has a distance from the center of the cover to any of the nozzles of this group that is less than the previous group of nozzles. 15. The method according to item 14, characterized in that a given amount of water is supplied to each group of nozzles in one cycle. 16. The method according to paragraph 14, characterized in that the water supply cycle is started based on a signal received from a temperature sensor located in the lower part of the shaft furnace body. 17. The method according to paragraph 14, characterized in that, based on a signal received from a temperature sensor located in the lower part of the shaft furnace body, before the start of the water supply cycle, the blast fan with which the shaft furnace is equipped is turned off. 18. The method according to item 14, characterized in that the water supply cycle is terminated based on a signal received from a temperature sensor located in the upper part of the shaft furnace body.