A heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area

Abstract

This invention relates to the field of coal dry distillation and energy-saving and environmental protection technology in the coking industry, specifically to a heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted zone. The system includes: a mild heat exchange anti-condensation section, whose inlet is connected to the raw coal gas outlet of the coke oven carbonization chamber, which cools the high-temperature raw coal gas to a temperature higher than the tar condensation initiation temperature; a heat preservation transition section, whose inlet is connected to the outlet of the mild heat exchange anti-condensation section; a topological deflection node, whose inlet is connected to the outlet of the heat preservation transition section, and whose internal guiding structure is used to change the airflow direction of the raw coal gas from upward to downward; and a zigzag flow controllable condensation section, whose inlet is connected to the downward outlet of the topological deflection node, including an inclined heat exchange channel whose axis is inclined at an acute angle to the horizontal plane, causing the condensed tar to flow downstream along the wall. This application solves the problem of tar backflow and coking in the deep cooling of raw coal gas, achieving both safety and efficient waste heat recovery.

Description

Technical Field

[0001] This invention relates to the field of coal dry distillation and energy conservation and environmental protection technology in the coking industry, specifically to a heat exchange and cleaning mechanical system for tar-containing raw coal gas across the condensation restricted zone. Background Technology

[0002] During the coking process, the raw coal gas produced in the carbonization chamber reaches temperatures as high as 750℃~800℃, and is rich in heavy tar components (its wall condensation initiation temperature is approximately 440℃). For a long time, the industry has been constrained by a causal chain of "condensation-backflow-carbon deposition": once the heat exchanger tube wall temperature falls below the tar dew point, the condensed liquid tar will flow against gravity back to the carbonization chamber outlet area (above 600℃) along the upward tube wall, where it will be dried, dehydrogenated, and form hard graphite rings, ultimately leading to pipe diameter reduction or even production shutdown. Therefore, traditional processes must install heat exchangers inside the riser tubes and maintain the outlet temperature at ≥500℃, resulting in a massive amount of sensible heat between 500℃ and 80℃ being wasted through ammonia spraying in the bridge tubes.

[0003] While existing technologies have made various attempts to improve the above-mentioned problems, none have fundamentally broken the aforementioned causal chain:

[0004] 1. Wall temperature controlled type (e.g., CN212512588U): This method uses a constant wall temperature ≥500℃, insulation layer, or phase change working fluid for regulation. The core idea is to "avoid condensation." This method essentially sacrifices the possibility of deep cooling.

[0005] 2. Anti-adhesion coating type (e.g., CN204478876U, CN205473564U): This type uses a non-stick coating combined with an inclined structure to attempt to allow the condensed tar to slide off. However, this approach acknowledges the fact that "tar has already condensed in the danger zone," essentially a passive tightrope walk; once the coating cracks under thermal shock, the tar will still anchor and coke. Furthermore, it lacks a "full gas phase anchoring section," and the inlet directly connects to high-temperature raw coal gas, posing an extremely high risk.

[0006] 3. Bridge tube embedded type: A heat exchanger is set in the descending section of a traditional bridge tube, but the airflow is in a diffuse state rather than a controlled topology, the tar condensation location is uncertain, and the counterflow path is not geometrically blocked.

[0007] 4. Segmented heat pipe type (e.g., CN101619848B): Although temperature division is implemented, its lower section still faces the risk of tar condensation (therefore, the actual outlet temperature rarely drops to 150℃, and is usually handled by ammonia water at around 280℃). This scheme does not adopt the structural solution of "topology flipping + gravity drainage channel", and the section below 500℃ still uses the traditional bridge tube or box structure.

[0008] In summary, there is an urgent need in this field for a solution that does not rely on coatings or insulation, but rather completely cuts off the "tar condensation → backflow → drying" path at the fluid topology level, in order to achieve safe and deep cooling and waste heat recovery of raw coal gas. Summary of the Invention

[0009] The present invention aims to solve the technical problem in the prior art that it is impossible to safely cool raw coal gas from 750℃~800℃ to the 200℃ range without ensuring coking.

[0010] The specific technical solution is as follows: A heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted zone includes: The mild heat exchange anti-condensation section has its inlet connected to the raw coal gas outlet of the coke oven carbonization chamber. The mild heat exchange anti-condensation section cools the high-temperature raw coal gas to a temperature higher than the tar condensation initiation temperature. The insulated transition section has its inlet connected to the outlet of the mild heat exchange and anti-condensation section, and its insulation structure ensures that the raw coal gas remains in the full gas phase when it passes through. The topology turning node has its inlet connected to the outlet of the insulation transition section. The topology turning node is equipped with a guide structure inside, which is used to change the airflow direction of the raw coal gas from an upward direction to a downward direction. The zigzag-guided controllable condensation section has an inlet connected to the downward outlet of the topological turning node, including an inclined heat exchange channel whose axis is inclined at an acute angle to the horizontal plane, causing the condensed tar to flow downstream along the wall.

[0011] The mild heat exchange anti-condensation section includes: The vertical steel pipe has an internal channel for the raw coal gas to flow from bottom to top; The multi-stage heat exchange coil unit is spirally wound around the inner cylinder of the vertical steel component and arranged in segments along the height direction, dividing the vertical steel component into multiple independent heat exchange sections distributed from bottom to top. The temperature detection unit includes multiple thermocouples embedded in the inner wall of each heat exchange section, which are used to detect the inner wall temperature of the corresponding heat exchange section in real time. A multi-media cooling system, including media supply pipelines that are connected to the coil units of each heat exchange section; The flow regulation unit includes an electric flow regulating valve and a flow meter corresponding to each heat exchange section coil unit. Each electric flow regulating valve and flow meter is installed on the medium inlet pipeline of the corresponding heat exchange section coil. The controller is electrically connected to the temperature detection unit and the flow regulation unit, respectively.

[0012] The multiple independent heat exchange sections are two in number, namely the first heat exchange section and the second heat exchange section, which are distributed sequentially from bottom to top.

[0013] The multi-medium cooling system includes a first medium interface and a second medium interface, which are used to connect to external steam and heat transfer oil, respectively. The first medium interface is connected to the heat exchange coil in the first heat exchange section and is used to introduce steam as a cooling medium into it. The second medium interface is connected to the heat exchange coil in the second heat exchange section and is used to introduce heat transfer oil as a cooling medium into it.

[0014] The insulation transition section is a combined elbow and vertical pipe structure, including: The composite pipe body, from the inside to the outside in the radial direction, includes a high-temperature alloy inner liner, a fire-resistant buffer layer, a heat insulation layer, and a metal outer shell; Multiple radial supports are fixed between the metal outer shell and the high-temperature alloy inner tube to support the fire-resistant buffer layer.

[0015] The high-temperature alloy inner tube is a high-temperature alloy sintered tube; the refractory buffer layer is a corundum mullite castable layer; the heat insulation layer, as a heat preservation layer, is an aerogel fiber layer; the metal outer shell is a steel pipe; and the inner wall of the steel pipe is coated with an infrared reflective coating.

[0016] The guide structure is a V-shaped bend, with its two ends connected to the inlet of the inclined heat exchange channel and the outlet of the vertical pipe, respectively.

[0017] The zigzag flow-guided controllable condensation section also includes a downward vertical pipe heat exchange channel connected to the lower end of the inclined heat exchange channel.

[0018] It also includes a cleaning module, arranged on the wall tar-laden area of ​​the controllable condensation section with zigzag flow; the cleaning module includes: First cleaning unit: The trolley moves back and forth along the axis of the inclined heat exchange channel; The nozzle is mounted on a mobile trolley and aimed at the inner wall of the inclined heat exchange channel; The drive mechanism is connected to the mobile trolley via a transmission and is used to drive the trolley to move. Second cleaning unit: A high-position fixed spray head is installed at the top of the downward vertical pipe heat exchange channel. The spray head is equipped with an annular nozzle and is configured to spray cleaning medium downward to clean the inner wall of the downward vertical pipe heat exchange channel.

[0019] The beneficial effects of this application are as follows:

[0020] First, the pipe wall temperature is consistently maintained above the temperature at which tar begins to condense through a gentle heat exchange anti-condensation section, ensuring the tar remains in the full gas phase and fundamentally eliminating the possibility of tar backflow. Furthermore, a topological deflection node is used to redirect the airflow from upward to downward, while simultaneously guiding the liquid flowing down the inner wall to a lower downstream position to prevent backflow. Second, deep cooling is achieved, safely cooling the raw coal gas to below 200℃, realizing deep waste heat recovery and resulting in significant energy savings. Third, by first using an inclined heat exchange channel to allow a large amount of tar to flow down the pipe wall, followed by further deep cooling using a downward vertical pipe heat exchange channel, the combination of these two methods is both less prone to clogging and ensures sufficient heat exchange. Additionally, movable and fixed spray nozzles are provided to periodically clean the pipe wall or when tar accumulates to a certain thickness, preventing scale buildup after long-term operation. This application solves the problem of tar backflow and coking in the deep cooling of raw coal gas, achieving both safety and efficient waste heat recovery. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall system structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the thermal insulation transition section structure in this invention;

[0023] Among them, 10. Mild heat exchange anti-condensation section; 20. Insulation transition section; 30. Topological turning node; 40. Bending line flow controllable condensation section; 50. Gas collection pipe; 11. Vertical pipe steel components; 21. Y-type bracket; 22. High temperature butterfly valve; 23. Sealed gate valve; 24. High temperature alloy sintered pipe; 25. Corundum mullite castable layer; 26. Aerogel fiber layer; 27. Steel pipe; 31. Guide structure; 41. Inclined heat exchange channel; 42. Downward vertical pipe heat exchange channel; 61. Moving trolley; 62. Spray head; 63. Spray head; 64. Guide wheel; 65. Rigid unidirectional push chain; 66. Metal hose. Detailed Implementation

[0024] To better explain and facilitate understanding of this invention, the following description is provided in conjunction with the appendix. Figure 1-2 The technical solution and effects of the present invention will be described in detail through specific implementation methods.

[0025] This embodiment provides a heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted zone, including: The mild heat exchange anti-condensation section 10 has its inlet connected to the raw coal gas outlet of the coke oven carbonization chamber. The mild heat exchange anti-condensation section 10 cools the high-temperature raw coal gas to a temperature higher than the tar condensation initiation temperature. The insulated transition section 20 has its inlet connected to the outlet of the mild heat exchange and anti-condensation section 10, and its insulation structure ensures that the raw coal gas remains in the full gas phase when it passes through. The topology turning node 30 has its inlet connected to the outlet of the insulation transition section 20. The topology turning node 30 is provided with a guide structure 31 inside, which is used to change the airflow direction of the raw coal gas from an upward direction to a downward direction. The zigzag-guided controllable condensation section 40 has its inlet connected to the downward outlet of the topology turning node 30, and includes an inclined heat exchange channel 41 whose axis is inclined at an acute angle to the horizontal plane, so that the condensed tar flows downstream along the wall.

[0026] In this embodiment, as Figure 1 As shown, the system includes, in sequence along the flow direction of raw coal gas: a mild heat exchange anti-condensation section 10, a heat preservation transition section 20, a topological turning node 30, and a zigzag flow controllable condensation section 40, with each section being sealed and connected in sequence.

[0027] Specifically, the inlet of the mild heat exchange anti-condensation section 10 is connected to the raw coal gas outlet of the carbonization chamber, and has an internal heat exchange medium channel. That is, this section adopts a mild heat exchange structure (external coil structure heat exchanger) to cool the raw coal gas at 750℃~800℃ to the outlet temperature (e.g., 580℃±10℃). The wall temperature of this section is always higher than the tar condensation initiation temperature (about 440℃), so that the tar remains in the gas phase, avoiding the precipitation of liquid tar and backflow into the carbonization chamber. The heat exchange power is controlled at a mild heat exchange level to prevent violent heat exchange from causing a sudden drop in local temperature and tar precipitation.

[0028] The inlet of the heat-insulating transition section 20 is connected to the outlet of the mild heat exchange and anti-condensation section 10. It is constructed as a low heat loss channel, with a temperature drop ΔT ≤ 10℃ when raw coal gas passes through, ensuring that the tar vapor is still in a fully gaseous state before entering the topological turning node 30.

[0029] The inlet of the topology turning node 30 is connected to the outlet of the insulated transition section 20. An internal guide structure 31 is provided to force the airflow direction to change from upward to downward; at the same time, it guides the liquid flowing down the inner wall to a lower downstream position to prevent backflow.

[0030] The inlet of the controllable condensation section 40 with a zigzag flow guide is connected to the outlet of the topology turning node 30. This includes an inclined heat exchange channel 41, whose axis forms an acute angle (e.g., 5°–45°) with the horizontal plane. The raw coal gas is cooled to 360°C. In this section, the raw coal gas is cooled to below the tar dew point, and some of the tar begins to condense into a liquid film, which flows automatically downstream along the inclined wall and cannot flow back to the upstream sections or the carbonization chamber.

[0031] The mild heat exchange anti-condensation section 10 includes: Vertical steel component 11, which forms a channel for the raw coal gas to flow from bottom to top; The multi-stage heat exchange coil unit is spirally wound around the inner outer wall of the vertical steel pipe 11 and arranged in segments along the height direction, dividing the vertical steel pipe 11 into multiple independent heat exchange sections distributed from bottom to top. The temperature detection unit includes multiple thermocouples embedded in the inner wall of each heat exchange section, which are used to detect the inner wall temperature of the corresponding heat exchange section in real time. A multi-media cooling system, including media supply pipelines that are connected to the coil units of each heat exchange section; The flow regulation unit includes an electric flow regulating valve and a flow meter corresponding to each heat exchange section coil unit. Each electric flow regulating valve and flow meter is installed on the medium inlet pipeline of the corresponding heat exchange section coil. The controller is electrically connected to the temperature detection unit and the flow regulation unit, respectively.

[0032] Specifically, the vertical steel component 11 forms a channel for the raw coal gas to flow from bottom to top, with its inlet connected to the raw coal gas outlet of the coke oven carbonization chamber. The multi-stage heat exchange coil unit adopts a spiral coil structure, coiled in sections along the height direction on the outer wall of the inner cylinder of the vertical steel component 11. In this embodiment, the vertical steel component 11 is divided into multiple independent heat exchange sections, each section of the coil being independent of the others. Two thermocouples are embedded inside the inner cylinder wall of each heat exchange section to monitor the inner wall temperature of that section in real time. The multi-medium cooling system includes medium supply pipelines connected to the coil units of each heat exchange section. Different cooling media can be introduced into different heat exchange sections according to their temperature range, achieving segmented medium cooling. Electric flow regulating valves and flow meters are installed on the medium inlet pipelines of each heat exchange section coil, respectively, to regulate and monitor the cooling medium flow rate of the corresponding heat exchange section. The controller (not shown in the figure) is implemented using a PLC controller, electrically connected to each thermocouple and each electric flow regulating valve. The controller is configured to: obtain the temperature change rate dT / dt of each heat exchange section based on the temperature detected by the thermocouple; and control the corresponding electric flow regulating valve to reduce its opening when the temperature change rate dT / dt of any heat exchange section exceeds a preset threshold. In other words, it obtains the temperature change rate dT / dt of each heat exchange section based on the temperature detected by the thermocouple, and controls the corresponding electric flow regulating valve to reduce its opening when the dT / dt of any heat exchange section exceeds a preset threshold (e.g., 30℃ / s).

[0033] The multiple independent heat exchange sections are two in number, namely the first heat exchange section and the second heat exchange section, which are distributed sequentially from bottom to top.

[0034] Specifically, there are two independent heat exchange sections. The first heat exchange section (lower section) and the second heat exchange section (upper section) are distributed sequentially from bottom to top along the height direction of the vertical steel pipe 11.

[0035] In this embodiment, the riser heat exchange coil has 60 layers, distributed sequentially along the height direction. Wherein: The first heat exchange section corresponds to the coils from the 1st to the 30th floor. This section is located at the inlet of the raw coal gas and has the highest temperature. The second heat exchange section corresponds to the coils from the 31st to the 60th floor. The temperature of the raw coal gas in this section is lower.

[0036] The multi-medium cooling system includes a first medium interface and a second medium interface, which are used to connect to external steam and heat transfer oil, respectively. The first medium interface is connected to the heat exchange coil in the first heat exchange section and is used to introduce steam as a cooling medium into it. The second medium interface is connected to the heat exchange coil in the second heat exchange section and is used to introduce heat transfer oil as a cooling medium into it.

[0037] Specifically, the first medium interface of the multi-medium cooling system is connected to the heat exchange coil in the first heat exchange section, and steam is introduced into it as the cooling medium. Since the raw coal gas temperature is highest in the first heat exchange section, the steam, as the cooling medium, indirectly exchanges heat with the raw coal gas, resulting in a gentle and controllable heat absorption and a gradual temperature drop in the raw coal gas. The introduced steam is saturated steam at 0.8MPa~1.6MPa, and its temperature rises to 540℃, becoming superheated steam, which is then sent to the turbine for power generation. The second medium interface is connected to the heat exchange coil in the second heat exchange section, and heat transfer oil (350℃ inlet / 380℃ outlet) is introduced into it as the cooling medium. The heat transfer oil has good temperature field stability, avoiding drastic temperature changes. The circulating heat transfer oil has a high temperature, with a small temperature difference between it and the raw coal gas, resulting in a slow heat transfer rate. Compared with water vaporization heat absorption, it avoids localized drastic cooling and prevents tar vapor condensation.

[0038] The preset thresholds include a first threshold corresponding to the first heat exchange section and a second threshold corresponding to the second heat exchange section. Specifically, when the controller determines that the temperature change rate dT / dt of a certain heat exchange section exceeds the preset threshold (e.g., greater than 30℃ / s) based on the temperature detected by the thermocouple, it determines that the temperature of that heat exchange section is rapidly decreasing and issues a corresponding control action.

[0039] When the controller determines that the rate of temperature change dT / dt exceeds a preset threshold, it controls the corresponding electric flow regulating valve to adjust the cooling medium flow rate to 50% of the current flow rate. That is, it controls the electric flow regulating valves corresponding to the lower and upper heat exchange coil units to reduce the flow rate of heat transfer oil and steam to 50% of the current flow rate. The thermal inertia of the raw coal gas is used to prevent the local temperature from dropping below the tar condensation point.

[0040] The first and second heat exchange sections each have two thermocouples, with each thermocouple corresponding to a heat exchange coil within its respective section. Specifically, the thermocouples are arranged along the height of the vertical steel component 11, with a spacing of 500mm between adjacent thermocouples. This spacing allows for real-time acquisition of temperature data at various heights, thereby obtaining the temperature gradient along the pipe's length.

[0041] In this embodiment, the vertical steel component 11 includes an inner cylinder and an outer cylinder. The inner cylinder forms a channel for the raw coal gas to flow from bottom to top. An annular space is formed between the outer wall of the inner cylinder and the inner wall of the outer cylinder, which is used for multi-stage heat exchange coils to be wound in sections along the height direction on the outer wall of the inner cylinder of the vertical steel component 11.

[0042] The insulation transition section 20 is a combined elbow and vertical pipe structure, including: The composite pipe body, from the inside to the outside in the radial direction, includes a high-temperature alloy inner liner, a fire-resistant buffer layer, a heat insulation layer, and a metal outer shell; Multiple radial supports are fixed between the metal outer shell and the high-temperature alloy inner tube to support the fire-resistant buffer layer.

[0043] Specifically, the composite pipe body comprises, from the inside out, a high-temperature alloy inner liner, a refractory buffer layer, an insulation layer, and a metal outer shell, used to reduce heat loss while transporting raw coal gas. Multiple radial supports are fixed between the metal outer shell and the high-temperature alloy inner liner to support the refractory buffer layer and prevent it from settling or slipping. The elbow and riser are integrated; the elbow inlet is welded to the riser steel component 11 outlet via a tee pipe. A high-temperature butterfly valve 22 is installed inside the elbow to control the flow of raw coal gas. A sealing gate valve 23 is located at the upper end of the tee pipe as a backup interface.

[0044] The high-temperature alloy inner tube is a high-temperature alloy sintered tube 24; the refractory buffer layer is a corundum mullite castable layer 25; the heat insulation layer, as a heat preservation layer, is an aerogel fiber layer 26; the metal outer shell is a steel pipe 27; the inner wall of the steel pipe 27 is coated with an infrared reflective coating.

[0045] like Figure 2 As shown, specifically, the high-temperature alloy sintered tube 24 is 10mm thick, with a temperature resistance >1000℃, and is resistant to coal gas corrosion and mechanical impact; the corundum-mullite castable layer 25 is 100mm thick, with a thermal conductivity ≤0.02W / (m·K), and is fixed to the outer wall of the high-temperature alloy sintered tube 24 by a high-temperature resistant inorganic binder; the aerogel fiber layer 26 is 25mm thick, with a thermal conductivity <0.0002W / (m·K); the metal outer shell is a steel pipe 27. The inner wall of the steel pipe 27 is coated with a 2mm thick infrared reflective coating, which is formed by curing nano-ceramic heat insulation coating and is used to reflect radiant heat. The radial support is a Y-shaped bracket 21, which passes through the corundum-mullite castable layer and the aerogel fiber layer, and is welded and fixed at both ends to the high-temperature metal tube and the steel pipe 27 respectively, while also providing support and preventing peeling of the corundum-mullite castable layer.

[0046] The guide structure 31 is a V-shaped bend, with its two ends connected to the inlet of the inclined heat exchange channel 41 and the outlet of the vertical pipe, respectively.

[0047] Specifically, the V-shaped bend is inclined downwards, with one end connected to the outlet of the vertical pipe via a flange, and the other end connected to the inlet flange of the inclined heat exchange channel 41, which is used to change the airflow direction from upward to downward.

[0048] The zigzag flow-guided controllable condensation section 40 also includes a downward vertical pipe heat exchange channel 42 connected to the lower end of the inclined heat exchange channel 41.

[0049] Specifically, such as Figure 1 As shown, the controllable condensation section 40 with zigzag flow also includes a descending vertical heat exchange channel 42. Its inlet is connected to the lower end of the inclined heat exchange channel 41 via a connecting cavity (connected to the flanges of the inclined heat exchange channel 41 and the descending vertical heat exchange channel 42 respectively), with the axis in the vertical direction. The raw coal gas is further cooled to a lower temperature (e.g., 180°C) in this section. The raw coal gas and condensed tar flow into the bottom gas collecting pipe 50, with no risk of backflow. In this embodiment, both the inclined heat exchange channel 41 and the descending vertical heat exchange channel 42 adopt an indirect water-cooled cooling structure. The raw coal gas flows inside the pipe, while the cooling medium flows outside the pipe jacket or coil. The remaining heat of the raw coal is indirectly transferred to the water. The water vaporizes and absorbs heat, causing the temperature of the raw coal gas to drop rapidly. The heat transfer rate is high-power. After the inclined heat exchange channel 41 and the descending vertical heat exchange channel 42 are connected in series for heat exchange, the temperature of the raw coal gas can drop to 200°C ± 10°C. Finally, the raw coal gas enters the gas collecting pipe 50, where it is sprayed with ammonia water and cooled to 80°C. The inclined heat exchange channel 41 is equipped with thermocouples electrically connected to the controller to detect the inner wall temperature of the corresponding heat exchange section; the cooling medium for this section is a steam-water mixture. The downward vertical pipe heat exchange channel 42 is equipped with thermocouples electrically connected to the controller to detect the inner wall temperature of the corresponding heat exchange section; the cooling medium for this section is water.

[0050] It also includes a cleaning module 60, arranged in the tar-laden area on the wall of the zigzag-guided controllable condensation section 40; the cleaning module includes: First cleaning unit: The trolley 61 moves back and forth along the axis of the inclined heat exchange channel 41; Nozzle 62 is mounted on the mobile trolley 61 and aligned with the inner wall of the inclined heat exchange channel 41; The drive mechanism is connected to the mobile trolley 61 and is used to drive the trolley to move.

[0051] Second cleaning unit: A high-position fixed spray head 63 is installed at the top of the downflow vertical pipe heat exchange channel 42. The spray head is equipped with an annular nozzle and is configured to spray cleaning medium downward to clean the inner wall of the downflow vertical pipe heat exchange channel 42.

[0052] Specifically, such as Figure 1As shown, the first cleaning unit of this system includes a mobile trolley 61 that reciprocates along the axis of the inclined heat exchange channel 41. Guide wheels 64 are installed at the bottom of the mobile trolley 61, rolling against the inner wall of the channel for guidance. A high-pressure conical nozzle 62 is fixed to the mobile trolley 61, spraying high-pressure water mist towards the inner wall of the inclined heat exchange channel 41 to flush away tar. A rigid unidirectional push chain 65, implemented using existing technology, is connected to the mobile trolley 61 as a drive mechanism to move the trolley. When the chain extends, each link locks to form a rigid rod, pushing the trolley forward. When the chain retracts, the links unlock and bend, causing the mobile trolley 61 to reset. In this embodiment, an existing electric chain plate mechanism is used to drive the chain to extend or retract. An electric chain plate mechanism refers to a drive device driven by a motor, which uses sprockets and chain plates to mesh and transmit power, thus extending or retracting the chain. The 310S metal flexible hose 66 has one end connected to a high-pressure conical nozzle and the other end extending through the channel wall to connect to an external cleaning medium source, and can bend freely as the trolley moves.

[0053] The second cleaning unit of this system includes a high-position fixed spray head 63, which is fixedly installed at the top of the downflow vertical pipe heat exchange channel 42 (connecting to the top of the cavity). Its lower end is equipped with a 360° annular high-pressure water jet nozzle, which sprays cleaning medium (high-pressure ammonia) downwards, forming a conical jet that covers the circumferential area of ​​the inner wall of the vertical pipe, effectively removing tar adhering to the wall surface. This spray head is connected to an external ammonia water source via a high-pressure ammonia water pipeline. The cleaning module can be activated periodically (e.g., when the wall tar thickness is ≥5mm), effectively preventing tar buildup and ensuring long-term system operation.

[0054] The working process of this embodiment includes the following steps: Phase 1: Mild heat exchange and anti-condensation section 10 The raw coal gas at 750℃~800℃ generated in the carbonization chamber is introduced into the vertical steel component 11; First, low-pressure steam is introduced into the coil of the first heat exchange section (lower section) to initially cool the raw coal gas and absorb sensible heat. Thermocouples monitor the inner wall temperature in real time. When the controller obtains the temperature change rate dT / dt based on the temperature feedback from the thermocouple and exceeds the preset threshold K > 25~50℃ / s range, the steam flow rate is reduced to 50% of the current flow rate to prevent tar condensation caused by local overcooling. Then, the heat transfer oil coil in the second heat exchange section (upper section) performs buffer heat exchange, and the thermocouple monitors the temperature in real time. When the temperature change rate dT / dt obtained by the controller exceeds the preset threshold K > 25~50℃ / s range, the heat transfer oil flow rate is reduced to 50% of the current flow rate to prevent tar condensation caused by local overcooling. Ultimately, the outlet temperature is maintained above 580℃ by utilizing phase change endothermic heat absorption. Based on real-time temperature data, the cooling medium flow rate of each group of coils is independently adjusted to ensure that the tube wall temperature is always higher than the tar condensation point temperature, so that the tar remains in a fully gaseous state.

[0055] Phase Two: Thermal Insulation Transition and Airflow Topology Reversal The raw coal gas, cooled to 580℃±10℃ in the mild heat exchange and anti-condensation section 10, enters the heat preservation transition section 20.

[0056] The heat-insulating transition section 20 has a high-temperature resistant insulation layer. When the raw coal gas passes through this section, the temperature drop is ≤10℃ due to the heat insulation effect of the insulation layer, maintaining a full gas phase state. It then enters the topology turning node 30, where the internal guiding structure 31 changes the airflow direction from upward to downward; the liquid guiding structure on the inner wall of the node directs any condensate to a lower downstream position to prevent backflow.

[0057] Phase 3: Controllable Condensation Section with Broken-Line Flow Guidance 40 The diverted raw coal gas (580℃±10℃) enters the inclined heat exchange channel 41, with its axis inclined at 5° to 45° to the horizontal plane. The raw coal gas is cooled to 360℃±10℃, and the precipitated liquid tar flows automatically away along the inclined wall to the lower end without backflow.

[0058] It then enters the downward vertical heat exchange channel 42, with its axis vertical. The raw coal gas is further cooled to 180℃~200℃, and the condensed tar flows rapidly downward along the inner wall of the vertical pipe into the bottom gas collecting pipe 50, achieving gas-liquid separation.

[0059] Phase 4: Cleaning Module The cleaning module is activated periodically (e.g., when the wall tar thickness is ≥5mm), effectively preventing tar buildup on the wall and ensuring long-term system operation.

Claims

1. A heat exchange and cleaning mechanical system for tar containing raw coal gas across the condensation forbidden zone, characterized in that, include: The mild heat exchange anti-condensation section (10) has its inlet connected to the raw coal gas outlet of the coke oven carbonization chamber. The mild heat exchange anti-condensation section (10) cools the high-temperature raw coal gas to a temperature higher than the tar condensation initiation temperature. The insulated transition section (20) has its inlet connected to the outlet of the mild heat exchange anti-condensation section (10), and its insulation structure keeps the raw coal gas in the full gas phase when it passes through. The topology turning node (30) has its inlet connected to the outlet of the insulation transition section (20). The topology turning node (30) is provided with a guide structure (31) inside, which is used to change the airflow direction of the raw coal gas from the upward direction to the downward direction. The zigzag flow controllable condensation section (40) has its inlet connected to the downward outlet of the topological turning (30) node, including an inclined heat exchange channel 41 whose axis is inclined at an acute angle to the horizontal plane, so that the condensed tar flows downstream along the wall.

2. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 1, characterized in that, The mild heat exchange anti-condensation section (10) includes: The vertical steel component (11) forms a channel inside for the raw coal gas to flow from bottom to top; The multi-stage heat exchange coil unit is spirally wound around the inner outer wall of the vertical steel pipe (11) and arranged in segments along the height direction, dividing the vertical steel pipe (11) into multiple independent heat exchange sections distributed from bottom to top. The temperature detection unit includes multiple thermocouples embedded in the inner wall of each heat exchange section, which are used to detect the inner wall temperature of the corresponding heat exchange section in real time. A multi-media cooling system, including media supply pipelines that are connected to the coil units of each heat exchange section; The flow regulation unit includes an electric flow regulating valve and a flow meter corresponding to each heat exchange section coil unit. Each electric flow regulating valve and flow meter is installed on the medium inlet pipeline of the corresponding heat exchange section coil. The controller is electrically connected to the temperature detection unit and the flow regulation unit, respectively.

3. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 2, characterized in that, The multiple independent heat exchange sections are two in number, namely the first heat exchange section and the second heat exchange section, which are distributed sequentially from bottom to top.

4. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 3, characterized in that, The multi-medium cooling system includes a first medium interface and a second medium interface, which are used to connect to external steam and heat transfer oil, respectively. The first medium interface is connected to the heat exchange coil in the first heat exchange section and is used to introduce steam as a cooling medium into it. The second medium interface is connected to the heat exchange coil in the second heat exchange section and is used to introduce heat transfer oil as a cooling medium into it.

5. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 1, characterized in that, The insulation transition section (20) is a combined elbow and vertical pipe structure, including: The composite pipe body, from the inside to the outside in the radial direction, includes a high-temperature alloy inner liner, a fire-resistant buffer layer, a heat insulation layer, and a metal outer shell; Multiple radial supports are fixed between the metal outer shell and the high-temperature alloy inner tube to support the fire-resistant buffer layer.

6. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 5, characterized in that, The high-temperature alloy inner tube is a high-temperature alloy sintered tube (24); the refractory buffer layer is a corundum mullite castable layer (25); the heat insulation layer is an aerogel fiber layer (26); the metal outer shell is a steel pipe (27); the inner wall of the steel pipe (27) is coated with an infrared reflective coating.

7. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 1, characterized in that, The guide structure (31) is a V-shaped bend, with its two ends connected to the inlet of the inclined heat exchange channel (41) and the outlet of the vertical pipe, respectively.

8. The heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 1, characterized in that, The zigzag flow controllable condensation section (40) also includes a downward vertical pipe heat exchange channel (42) connected to the lower end of the inclined heat exchange channel (41).

9. A heat exchange and cleaning mechanical system for tar-containing raw coal gas across a condensation restricted area according to claim 8, characterized in that, It also includes a cleaning module (60) arranged in the tar-laden area on the wall of the zigzag-guided controllable condensation section (40); the cleaning module includes: First cleaning unit: The mobile trolley (61) moves back and forth along the axis of the inclined heat exchange channel (41); The nozzle (62) is mounted on the mobile trolley (61) and aligned with the inner wall of the inclined heat exchange channel (41); The drive mechanism is connected to the mobile trolley (61) for driving the trolley to move; Second cleaning unit: A high-position fixed spray head (63) is set at the top of the down-stream heat exchange channel (42). The spray head is equipped with an annular nozzle and is configured to spray cleaning medium downward to clean the inner wall of the down-stream heat exchange channel (42).

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