A recovery apparatus for the gasification of pulverized coal

Abstract

This invention relates to the field of pulverized coal gasification waste gas treatment technology, and in particular to a recovery device for pulverized coal gasification processing, comprising a scrubbing tower. The inlet of the scrubbing tower is connected to the main outlet pipe of the high-pressure flash tank of the pulverized coal gasification system. The outlet of the scrubbing tower is sequentially connected to a gas-liquid separation unit and a three-stage reciprocating compressor unit. The outlet of the three-stage reciprocating compressor unit is connected to a syngas pipeline network. An adjustable screening packing assembly is installed at the top of the scrubbing tower. This device uses a three-layer nested adjustable screening packing assembly at the top of the tower. The circumferential motion of the motor is converted into axial reciprocating motion through a wave-like meshing surface, which can dynamically adjust the screening accuracy and achieve online self-cleaning of the packing. Combined with automatic differential pressure control and modular design, it completely solves the problem of traditional packing blockage, extending the continuous operation cycle from 1-3 months to 24 months, reducing operation and maintenance costs, and ensuring continuous and stable production.

Description

Technical Field

[0001] This invention relates to the field of pulverized coal gasification waste gas treatment technology, and in particular to a recovery device for pulverized coal gasification processing. Background Technology

[0002] In the pulverized coal gasification process, the slag and water section of the gasification workshop is equipped with multiple high-pressure flash tanks for flash treatment of gasification slag and water to produce high-pressure flash steam. The current industry practice for treating this high-pressure flash steam is to directly transport the flash steam produced by each high-pressure flash tank to the flare system for incineration via pressure regulating valves. For the solid impurities and particulate matter entrained in the flash steam, existing supporting purification units mostly adopt a single fixed grid-like filling structure at the top of the tower. The impurities in the gas flow are intercepted and separated by a static filling medium, thereby completing the initial purification of the flash steam.

[0003] In the special operating conditions of continuous production in pulverized coal gasification units, and the flash steam containing high dust and prone to ammonium salt crystallization, the existing treatment methods have unavoidable technical defects. The effective gas content in the flash steam is as high as 58%, and direct incineration results in a large amount of waste of usable resources. At the same time, the static fixed filling structure at the top of the tower has no self-cleaning function. After long-term operation, the filling structure is easily blocked by ash and ammonium salt crystals, which leads to a sharp increase in equipment pressure difference. It is necessary to shut down for maintenance before it can be restored to operation, which seriously restricts the continuity of pulverized coal gasification waste gas treatment and recycling. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that, under the special working conditions of high dust content and easy precipitation of ammonium salt crystals in pulverized coal gasification flash steam, the existing flash steam is directly flared and incinerated, resulting in the waste of effective gas resources. Moreover, the fixed purification and filling structure at the top of the tower has no self-cleaning ability and is prone to blockage, requiring shutdown for maintenance, and cannot guarantee the continuous and stable operation of waste gas recovery and utilization.

[0005] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a recovery device for pulverized coal gasification processing, including a washing tower. The inlet of the washing tower is connected to the main outlet pipe of the high-pressure flash tank of pulverized coal gasification. The outlet of the washing tower is sequentially connected to a gas-liquid separation unit and a three-stage reciprocating compressor unit. The outlet of the three-stage reciprocating compressor unit is connected to a syngas pipeline network. An adjustable sieve packing assembly is installed at the top of the washing tower.

[0006] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the adjustable screening packing assembly includes three cylinders coaxially stacked, the contact surfaces of two adjacent cylinders are machined with mutually matching wavy meshing surfaces, a drive motor is provided outside the washing tower, and the output end of the drive motor is connected to the cylinder located in the middle in a transmission connection.

[0007] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the three cylinders are a lower cylinder, a middle cylinder, and an upper cylinder, respectively. The upper and lower end faces of the upper cylinder and the lower cylinder are each provided with perforated partition mesh that matches the inner diameter of the corresponding cylinder. The lower cylinder is filled with large-aperture grid packing, the middle cylinder is filled with perforated plate corrugated packing, and the upper cylinder is filled with high-efficiency wire mesh defoaming packing.

[0008] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the drive motor is an explosion-proof magnetic drive motor, and the output shaft of the explosion-proof magnetic drive motor is connected to the middle cylinder through a sealed transmission mechanism, which is disposed through the side wall of the washing tower.

[0009] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention, a demineralized water booster pump group is further included. The demineralized water booster pump group includes a first booster pump and a second booster pump. The inlets of the first booster pump and the second booster pump share a demineralized water main pipe. The outlets of the first booster pump and the second booster pump are connected in parallel and then divided into two independent water inlet branches. Each of the two water inlet branches is equipped with an independent flow regulating valve and a shut-off valve.

[0010] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: a low-level water inlet is provided at the lower part of the side wall of the washing tower, and a high-level water inlet is provided at the middle part of the side wall. The two water inlet branches are respectively connected to the low-level water inlet and the high-level water inlet. A multi-layer baffle tray is provided inside the washing tower between the low-level water inlet and the high-level water inlet.

[0011] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the gas-liquid separation unit includes a primary gas-liquid separator and a compressor inlet fine separator. The inlet of the primary gas-liquid separator is connected to the outlet of the scrubbing tower via a pipeline, and the gas phase outlet of the primary gas-liquid separator is connected to the inlet of the compressor inlet fine separator via a pipeline.

[0012] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the three-stage reciprocating compressor unit includes a primary compression unit, a secondary compression unit and a tertiary compression unit connected in series, and the inlet of the primary compression unit is connected to the gas phase outlet of the compressor inlet fine separator through a pipeline.

[0013] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the primary compression unit includes a primary intake buffer tank, two parallel primary cylinders, a primary exhaust buffer tank, a primary cooler, and a primary separator connected in sequence; the secondary compression unit includes a secondary intake buffer tank, a secondary cylinder, a secondary exhaust buffer tank, a secondary cooler, and a secondary separator connected in sequence; and the tertiary compression unit includes a tertiary intake buffer tank, a tertiary cylinder, and a tertiary exhaust buffer tank connected in sequence.

[0014] In a preferred embodiment of the recovery device for pulverized coal gasification processing described in this invention: the side wall of the washing tower is equipped with a bottom level transmitter, a differential pressure transmitter, and a top temperature transmitter. The bottom level transmitter, the differential pressure transmitter, the top temperature transmitter, the demineralized water booster pump set, and the drive motor are all electrically connected to the intelligent control system.

[0015] The beneficial effects of this invention are as follows: By directly connecting the air inlet of the scrubbing tower to the main outlet pipe of the high-pressure flash tank of pulverized coal gasification, this device ensures that all high-pressure flash vapors can enter the recovery system, preventing some gas from being directly diverted to the flare for combustion at the source. The demineralized water booster pump set adopts a parallel structure of two pumps, one in operation and one on standby. In the event of a failure of either pump, automatic switching can be completed within 10 seconds, ensuring uninterrupted water supply for the scrubbing process and providing a fundamental guarantee for the continuous operation of the recovery process. The scrubbing tower adopts a scrubbing structure with layered water inlet and multi-layer baffle trays. The high-flow-rate scrubbing water sprayed from the low-level inlet quickly captures coarse particulate impurities, while the atomized scrubbing water sprayed from the high-level inlet precisely captures fine particles. The intermediate baffle trays extend the gas-liquid contact time and achieve gravity settling of medium-sized particles. The synergistic effect of these three elements ensures that the gas purification effect meets the requirements of the subsequent compression process. The gas-liquid separation unit employs a two-stage series separation structure. The primary separator removes over 90% of free droplets, while the compressor inlet fine separator further intercepts tiny droplets and solid particles smaller than 5 micrometers, ensuring the gas entering the compressor unit is clean and dry, thus preventing liquid slugging and wear failures. The three-stage reciprocating compressor unit progressively increases the gas pressure from 0.5 MPa to 4.0 MPa, perfectly matching the downstream syngas pipeline pressure. This allows the purified gas to be directly connected to the syngas pipeline as feedstock for downstream chemical production. Through the synergistic effect of the above structure, 100% recovery and utilization of the previously wasted flash vapor is achieved, with an effective gas recovery rate exceeding 98%, significantly reducing resource waste and simultaneously lowering carbon emissions and environmental pollution from flare combustion.

[0016] This device features a three-layer nested adjustable screening packing assembly installed at the top of the scrubbing tower. This assembly comprises three coaxially stacked cylindrical structures, with adjacent cylinders having mutually matching wavy meshing surfaces. An external drive motor is connected to the middle cylinder. When the drive motor rotates the middle cylinder, the wavy meshing surfaces convert the circular motion into axial reciprocating motion of the upper and lower cylinders. This motion, on the one hand, changes the axial spacing of the three packing chambers, adjusting the packing compaction and screening aperture, thereby dynamically adjusting the purification precision according to the dust content and gas volume of the flash vapor, maintaining optimal separation performance within a load range of 30% to 110%. On the other hand, the axial micro-vibrations generated by the axial reciprocating motion cause the accumulated dust and ammonium salt crystals adhering to the packing surface to detach, flowing downwards with the washing water and being discharged from the bottom of the tower, achieving online self-cleaning of the packing layer. Differential pressure transmitters installed at the top and bottom of the tower can monitor the flow resistance inside the tower in real time. When the differential pressure exceeds the set threshold of 5 kPa, the intelligent control system automatically starts the drive motor for self-cleaning. When the differential pressure returns to below 3 kPa, it automatically stops without manual intervention. The packing assembly adopts a modular integrated structure, which, together with the maintenance manhole at the top of the tower, makes the replacement and maintenance of the packing more convenient, without disassembling the entire tower, significantly shortening maintenance time. Through the synergistic effect of the above structures, the problems of easy clogging and frequent shutdowns for cleaning caused by traditional fixed packing are completely solved. The continuous maintenance-free operation cycle of the unit is extended from the traditional 1-3 months to more than 24 months, while reducing operation and maintenance costs and ensuring the continuous and stable operation of pulverized coal gasification production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein:

[0018] Figure 1 This is the overall process flow diagram of this application;

[0019] Figure 2 This is a schematic diagram of the interior of the scrubbing tower in this application;

[0020] Figure 3 This is a cross-sectional schematic diagram of the adjustable sieving packing assembly in this application;

[0021] Figure 4 This is a flow chart of the demineralized water booster pump unit in this application;

[0022] Figure 5 This is a flowchart of the main outlet pipe of the high-pressure flash tank in this application;

[0023] Figure 6 for Figure 1Enlarged view of a portion of the process flow of the gas-liquid separation unit and the three-stage reciprocating compressor unit.

[0024] In the picture:

[0025] 1. Scrubber; 11. Low-level water inlet; 12. High-level water inlet; 13. Air inlet; 14. Air outlet; 2. Gas-liquid separation unit; 21. Primary gas-liquid separator; 22. Compressor; 3. Three-stage reciprocating compressor unit; 31. First-stage compression unit; 32. Second-stage compression unit; 33. Third-stage compression unit; 4. Adjustable sieve packing assembly; 41. Lower cylinder; 42. Middle cylinder; 43. Upper cylinder; 44. Perforated partition mesh; 45. Corrugated meshing surface; 46. Large-aperture grid packing; 47. Perforated plate corrugated packing; 48. High-efficiency wire mesh defoaming packing; 49. Drive motor; 491. Sealing transmission mechanism; 5. Demineralized water booster pump unit; 51. First booster pump; 52. Second booster pump; 53. Demineralized water main pipe; 54. Water inlet branch; 541. Flow regulating valve; 542. Shut-off valve; 6. Air outlet main pipe. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0027] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0028] Reference Figure 1 This embodiment provides a recovery device for pulverized coal gasification processing, including a washing tower 1. The inlet 13 of the washing tower 1 is connected to the outlet main pipe 6 of the high-pressure flash tank of pulverized coal gasification. The outlet 14 of the washing tower 1 is connected in sequence to the gas-liquid separation unit 2 and the three-stage reciprocating compressor unit 3. The outlet of the three-stage reciprocating compressor unit 3 is connected to the syngas pipeline network. An adjustable sieve packing assembly 4 is installed at the top of the washing tower 1.

[0029] This device collects and transports all high-pressure flash vapor generated during the pulverized coal gasification process via pipelines. All process gases from the high-pressure flash tanks are uniformly collected into the main outlet pipe 6 and then enter the scrubbing tower 1, avoiding direct diversion of some gases to the flare system for incineration. This achieves centralized recovery and treatment of all flash vapor at the source. After preliminary purification in the scrubbing tower 1, the gas enters the gas-liquid separation unit 2 via pipelines. Under the combined action of gravity settling and inertial separation, free liquid droplets and trace solid impurities entrained in the gas phase are separated from the main gas phase, reducing the gas's moisture and dust content and providing qualified intake conditions for subsequent compression processes.

[0030] After gas-liquid separation, the clean gas enters the three-stage reciprocating compressor unit 3. Through a three-stage progressive pressurization process, the gas pressure is increased to a level matching the downstream syngas pipeline network. The heat generated during single-stage compression is promptly removed by a matching cooling device to prevent excessive gas temperature from causing equipment damage or media decomposition. The pressurized gas is then directly connected to the plant's syngas pipeline network and transported as feedstock to downstream chemical production sections for reaction, realizing the resource utilization of what was originally waste flash vapor. Furthermore, an adjustable sieve packing assembly 4 is installed at the top of the scrubbing tower 1. This assembly can dynamically adjust the size of its internal sieve channels through structural adjustments. Simultaneously, it generates micro-vibrations during operation, causing solid particles and crystals adhering to the packing surface to detach, preventing blockage of the packing layer and ensuring long-term continuous and stable operation of the unit.

[0031] Reference Figures 2-3 The adjustable screening packing assembly 4 includes three cylinders coaxially stacked, with the contact surfaces of two adjacent cylinders having mutually matching wavy meshing surfaces 45. A drive motor 49 is installed outside the washing tower 1, and the output end of the drive motor 49 is connected to the middle cylinder 42 for transmission.

[0032] Furthermore, the three cylinders are a lower cylinder 41, a middle cylinder 42, and an upper cylinder 43. The upper and lower end faces of the upper cylinder 43 and the lower cylinder 41 are provided with perforated partition mesh 44 that matches the inner diameter of the corresponding cylinder. The lower cylinder 41 is filled with large-aperture grid filler 46, the middle cylinder 42 is filled with perforated plate corrugated filler 47, and the upper cylinder 43 is filled with high-efficiency wire mesh defoaming filler 48.

[0033] Specifically, the adjustable sieve packing assembly 4 adopts a multi-layer nested cylindrical structure, with each cylinder stacked sequentially along the same axis to form an integral packing support unit. This coaxial arrangement ensures both adaptation to the outer shell of the scrubbing tower 1 and concentricity of the movement of each component, avoiding eccentric jamming during operation, while also facilitating the overall loading and replacement of the packing.

[0034] The contact surfaces of adjacent cylinders are machined with continuous wavy curved surfaces, and the curved surface contours of the upper and lower adjacent cylinders are perfectly matched, allowing them to fit tightly together. This curved surface structure replaces the traditional planar contact method, providing a mechanical basis for the transmission of axial motion, enabling circumferential rotation to be converted into axial linear motion.

[0035] The drive unit is located outside the washing tower 1, and its power output end is connected to the middle drum 42. By selecting the middle drum 42 as the driving component, it can transmit motion to both the upper and lower sides simultaneously. Compared with the single-sided drive structure, the power transmission is more uniform, the motion synchronization between the upper and lower sides is better, and the uneven force distribution problem that may occur in the single-sided drive is avoided.

[0036] When the drive unit rotates the middle cylinder 42 around its axis, the wavy surfaces on the contact surfaces of adjacent cylinders will slide relative to each other. Due to the continuous height difference between the surfaces, during rotation, the peaks of the middle cylinder 42 will successively contact the troughs and peaks of the upper and lower cylinders, thereby generating a periodic axial thrust on the upper and lower cylinders. Under the action of the axial thrust, the upper and lower cylinders will reciprocate along the axis of the receiving cavity opened on the inner wall of the washing tower 1. Specifically, multiple sets of elastic telescopic cylinders are provided between the lower cylinder 41 and the lower surface of the receiving cavity, and multiple sets of elastic telescopic cylinders are also provided between the upper cylinder 43 and the upper surface of the receiving cavity. In this way, when the middle cylinder 42 rotates, the corresponding elastic telescopic cylinders of the upper cylinder 43 and the lower cylinder 41 adaptively extend and retract to realize the up and down movement of the upper cylinder 43 and the lower cylinder 41.

[0037] The axial reciprocating motion of the upper and lower cylinders changes the axial distance between adjacent cylinders, thereby altering the compaction degree of the packing layer within the entire packing assembly. When the distance decreases, the packing is compacted, the internal gas flow channels become smaller, and smaller solid particles can be intercepted; when the distance increases, the packing becomes looser, the gas flow channels become larger, and the gas flow resistance decreases, making it suitable for high-flow-rate conditions. By controlling the rotation angle of the middle cylinder 42, the compaction degree of the packing layer can be precisely adjusted, thus achieving dynamic adjustment of screening accuracy under different operating conditions.

[0038] Meanwhile, the continuous rotation of the middle cylinder 42 causes high-frequency axial micro-vibrations in both the upper and lower cylinders. This vibration is transmitted to the packing material inside the cylinder, causing relative movement between the packing particles. Solid particles and ammonium salt crystals adhering to the packing surface are detached from the packing surface under the vibration, flowing downwards with the washing liquid and eventually being discharged from the bottom of the tower. This online self-cleaning method removes blockages in the packing layer without shutting down the unit, ensuring continuous and stable operation of the equipment.

[0039] The drive motor 49 is an explosion-proof magnetic drive motor. The output shaft of the explosion-proof magnetic drive motor is connected to the middle cylinder 42 through a sealed transmission mechanism 491. The sealed transmission mechanism 491 is installed through the side wall of the washing tower 1.

[0040] Specifically, the medium inside the scrubbing tower 1 of the pulverized coal gasification unit is a mixed gas containing flammable and explosive components such as carbon monoxide and hydrogen. The operating pressure inside the tower is higher than atmospheric pressure. If gas leakage occurs inside the tower, it will not only waste resources but also pose safety hazards such as fire and explosion. Therefore, the explosion-proof and sealing performance of the drive unit is a key factor in the safe operation of the unit.

[0041] To address the aforementioned operating requirements, this device provides two power transmission implementation schemes. The first scheme utilizes an explosion-proof magnetic drive motor as the power source. This type of motor achieves contactless power transmission through an internal magnetic coupler. The motor body is completely isolated from the external environment, eliminating the risk of electrical spark leakage and meeting the explosion-proof requirements of coal chemical plants. The motor's power output is connected to the inner cylinder 42 within the tower via a sealed transmission mechanism 491. The sealed transmission mechanism 491 extends through the side wall of the washing tower 1, and a static seal is used between it and the tower wall, fundamentally eliminating the possibility of flammable and explosive gases leaking through the transmission gap. Specifically, a ring of teeth is installed on the outer wall of the inner cylinder 42, and a gear meshing with it is located outside the ring of teeth. The gear is connected to the motor via a transmission shaft reducer, etc.

[0042] The second scheme employs a non-contact external magnetic drive structure, eliminating the need for a transmission shaft penetrating the tower wall. Multiple sets of permanent magnets are evenly arranged circumferentially on the outer wall of the middle cylinder 42. A rotatable annular component is positioned correspondingly on the outer side of the washing tower 1. Similarly, multiple sets of permanent magnets are evenly arranged circumferentially on the inner side of this annular component. The polarities of the permanent magnets on both sides are matched, generating sufficient magnetic coupling. When the outer annular component rotates around the axis of the washing tower 1, the rotating magnetic field generated by the inner permanent magnets penetrates the tower wall, causing the permanent magnets on the outer wall of the middle cylinder 42 to rotate synchronously, thus achieving the rotational motion of the middle cylinder 42. This scheme completely eliminates the transmission components penetrating the tower wall, maintaining a completely sealed state and achieving optimal sealing performance. It also reduces wear on transmission components and lowers the maintenance workload of the equipment.

[0043] Both drive schemes can achieve smooth rotation of the middle cylinder 42. The first scheme has a larger transmission torque and is suitable for working conditions with larger tower diameters and heavier packing components. The second scheme has higher sealing reliability and is suitable for production environments with extremely strict leakage control requirements.

[0044] The flash vapor from pulverized coal gasification flows upward within the scrubbing tower 1. This counter-current gas-liquid contact is fundamental to efficient scrubbing and purification, and the height arrangement of the inlets directly determines the sequence and effectiveness of the gas-liquid contact. The inlets of scrubbing tower 1 are arranged in layers along the tower's height. The lower inlet 11 is located near the gas phase inlet area at the bottom of the tower, while the higher inlet 12 is located in the gas phase rising channel area in the middle of the tower. Two independent water supply branches correspond to inlets at different heights, achieving a tiered supply of scrubbing water.

[0045] After entering from the bottom of the tower, the flash vapor first comes into contact with the washing water sprayed from the low-level inlet 11. At this point, the solid impurity content in the gas phase is the highest, mainly consisting of large-diameter coarse coal ash particles. The high-flow-rate washing water sprayed from the low-level inlet 11 forms a dense water curtain, which fully contacts the upward-flowing gas phase in the opposite direction. This quickly captures most of the coarse particles and large droplets, while simultaneously providing initial cooling to the high-temperature flash vapor and dissolving most of the water-soluble harmful impurities. After being washed in the lower layer, the gas phase has a significantly reduced content of coarse particles and continues to flow upwards along the tower.

[0046] Inside the tower body between the upper and lower inlets, a multi-layered horizontally arranged baffle structure is installed. As the gas phase passes through this area, its flow direction is altered multiple times by the baffle structure, creating a reversible flow between the baffles and significantly reducing its velocity. Medium-sized solid particles remaining in the gas phase, under the combined influence of gravity and inertia, detach from the main gas flow and settle downwards, eventually falling into the liquid accumulation area at the bottom of the tower. Simultaneously, the baffle structure prolongs the gas-liquid contact time, allowing incompletely captured impurities to fully contact the washing water, further enhancing the purification effect.

[0047] After being processed by the baffle structure, the gas phase continues to flow upward to the area where the high-level water inlet 12 is located, where it comes into countercurrent contact with the washing water sprayed from the high-level water inlet 12. At this point, only a small amount of fine dust and ammonium salt crystal particles remain in the gas phase. The washing water sprayed from the high-level water inlet 12, with its higher degree of atomization, can accurately capture these fine impurities, completing the deep purification of the gas phase. This arrangement of layered water inlet combined with the intermediate baffle structure achieves the graded removal of coarse and fine particles, avoiding the problems caused by a single water inlet, such as coarse particles clogging the upper spray and fine particles not being effectively removed. At the same time, it can adjust the water supply flow of the upper and lower layers according to the changes in the dust content of the gas phase, reducing the consumption of washing water while ensuring the purification effect.

[0048] The pulverized coal gasification process is a continuous operation, and the flash steam recovery unit needs to operate 24 hours a day without interruption. The stability of the washing water supply system directly determines the operational reliability of the entire unit. If the water supply is interrupted, solid impurities in the flash steam cannot be effectively removed and will directly enter the subsequent compressor unit, causing equipment wear or even damage. Therefore, the washing water supply system needs to have redundancy backup capabilities and flexible flow regulation capabilities.

[0049] The washing water supply system of this device adopts a dual-pump parallel structure. The inlet ends of both pumps are connected to the same desalinated water delivery main pipe, ensuring that the water supply source and inlet pressure of both pumps are consistent, avoiding fluctuations in water supply parameters due to differences in water sources. The outlet ends of the two pumps are connected in parallel through pipelines. This structure allows either pump to independently handle the entire water supply task. During normal operation, only one pump needs to be started to meet the washing needs, while the other pump is in hot standby mode. If the operating pump experiences motor overload, mechanical seal leakage, or other malfunctions, the standby pump can be started immediately and the faulty pump can be shut down. The entire switching process does not require interruption of water supply, ensuring the continuous operation of the washing process.

[0050] The parallel main water supply pipe is further divided into two independent water supply branches, each corresponding to a different spray layer at a different height within the scrubbing tower 1. Each branch is equipped with an independent flow regulating component and a pipe shut-off component. The flow regulating component precisely controls the water supply flow rate of the corresponding branch, while the pipe shut-off component completely isolates the branch from the system during maintenance or malfunction. By adjusting the water supply flow rates of the two branches, the spray intensity of different spray layers within the scrubbing tower 1 can be independently controlled. When the flash vapor dust content is high, the flow rate of the lower spray branch can be increased to enhance the removal of coarse particles; when higher gas purification precision is required, the flow rate of the upper spray branch can be increased to enhance the capture of fine particles. This independent branch design allows the scrubbing process to be flexibly adjusted according to changes in flash vapor conditions, ensuring purification effectiveness while achieving efficient water resource utilization.

[0051] The pulverized coal gasification flash steam recovery unit is a continuous operation system. Real-time monitoring and automatic control of the internal operating parameters of the scrubbing tower 1 are the core links to ensure stable operation, achieving the required purification effect, and safe production. Various detection elements installed at different locations within the tower can convert the physical state inside the tower into transmittable electrical signals, providing a data foundation for the system's automatic control.

[0052] A liquid level detection element installed in the liquid accumulation area at the bottom of the tower can collect real-time information on the height of the liquid phase at the bottom of the tower. When the liquid level at the bottom of the tower rises, it indicates that the inflow of washing water is greater than the outflow. If the liquid level continues to rise to the overflow position, it will cause liquid to be carried over to the gas outlet, affecting the subsequent gas-liquid separation effect. When the liquid level at the bottom of the tower falls, it indicates that the outflow of washing water is greater than the inflow. If the liquid level is too low, the gas phase will directly escape from the drain port, causing a safety hazard. After the liquid level detection element transmits the collected liquid level signal to the control system, the control system will automatically adjust the opening of the inlet valve and the drain valve according to the preset liquid level range to maintain the liquid level at the bottom of the tower within a stable operating range.

[0053] Pressure detection points are installed at the bottom and top of the tower to collect gas phase pressure information at both ends. The signal difference between the two pressure detection points reflects the resistance to gas flow within the tower. When solid particles or ammonium salt crystals deposit on the packing layer or tray surface, the gas flow channel narrows, increasing flow resistance and consequently raising the pressure difference between the top and bottom ends. After the pressure difference signal is transmitted to the control system, if the difference exceeds a preset threshold, the control system automatically activates the drive device at the top of the tower, causing the packing assembly to vibrate axially and remove deposits and crystals adhering to the packing surface. Once the pressure difference returns to the normal range, the control system automatically stops the drive device.

[0054] Temperature sensors installed at the gas phase outlet at the top of the tower collect the temperature information of the purified gas. The tower top temperature directly reflects the cooling effect of the washing water and whether the spray volume is sufficient. If the tower top temperature is too high, it indicates that the spray volume of washing water is insufficient and cannot effectively cool the high-temperature flash vapor. It will also lead to an increase in the water vapor content entrained in the gas phase, increasing the load on the subsequent gas-liquid separation unit 2. After the temperature sensors transmit the collected temperature signal to the control system, the control system will automatically adjust the total flow rate of washing water according to the preset temperature range to ensure that the tower top temperature is maintained within a reasonable range.

[0055] All signals collected by the detection elements are transmitted to the intelligent control system, and the control loops of the demineralized water delivery unit and the tower top drive device are also connected to this system. Based on real-time data from each detection element, the control system can automatically perform a series of control actions according to a preset logic program, such as adjusting the washing water flow rate, switching the booster pump set for failure, and self-cleaning the packing assembly, without manual intervention. This centralized automatic control method improves the operational stability of the equipment, reduces human error, and can respond promptly to changes in operating conditions, ensuring that the equipment maintains optimal operating status under different loads.

[0056] The gas-liquid separation unit 2 includes a primary gas-liquid separator 21 and a compressor 22 inlet fine separator. The inlet of the primary gas-liquid separator 21 is connected to the gas outlet 14 of the scrubbing tower 1 through a pipeline, and the gas phase outlet of the primary gas-liquid separator 21 is connected to the inlet of the compressor 22 inlet fine separator through a pipeline.

[0057] The three-stage reciprocating compressor unit 3 includes a first-stage compression unit 31, a second-stage compression unit 32, and a third-stage compression unit 33 connected in series. The inlet of the first-stage compression unit 31 is connected to the gas phase outlet of the fine separator at the inlet of the compressor 22 via a pipeline. The first-stage compression unit 31 includes a first-stage intake buffer tank, two parallel first-stage cylinders, a first-stage exhaust buffer tank, a first-stage cooler, and a first-stage separator connected in series. The second-stage compression unit 32 includes a second-stage intake buffer tank, a second-stage cylinder, a second-stage exhaust buffer tank, a second-stage cooler, and a second-stage separator connected in series. The third-stage compression unit 33 includes a third-stage intake buffer tank, a third-stage cylinder, and a third-stage exhaust buffer tank connected in series.

[0058] Specifically, the gas purified by scrubbing tower 1 still contains a small amount of free liquid droplets and fine solid particles. If it directly enters the compressor unit, the droplets will cause liquid slugging in the cylinder, damaging moving parts such as the cylinder and piston. The solid particles will accelerate the wear of the cylinder wall and piston rings, shortening the service life of the equipment. Therefore, a two-stage gas-liquid separation device is installed between scrubbing tower 1 and the compressor unit to purify the gas phase step by step.

[0059] The first-stage gas-liquid separation device employs a structure combining gravity settling and inertial separation. Upon gas entry, the flow cross-sectional area suddenly increases, and the airflow velocity decreases significantly. Larger liquid droplets in the gas phase naturally settle to the bottom of the device under gravity. Simultaneously, the airflow direction changes due to the baffles inside the device, causing droplets to impact the baffle surface and accumulate before falling due to inertial forces. After the first-stage separation, over 90% of the free liquid droplets in the gas phase are removed, resulting in a significant reduction in the gas's moisture content.

[0060] The second-stage gas-liquid separation unit is a high-precision separator with internal micro-filters that intercept tiny droplets and solid particles smaller than 5 micrometers that were not removed in the first stage. As gas passes through the filter, droplets and solid particles are trapped on its surface, while clean gas flows out from the center. After two stages of gas-liquid separation, the content of droplets and solid particles in the gas phase is reduced to the allowable intake standard for the compressor unit, effectively protecting the safe and stable operation of subsequent compression equipment.

[0061] The initial pressure of the high-pressure flash steam from pulverized coal gasification is approximately 0.5 MPa, while the operating pressure of the downstream syngas pipeline is approximately 4.0 MPa. Therefore, a compressor unit is needed to boost the gas pressure to the target value. If a single-stage compression method is used, an excessively high compression ratio will cause a sharp increase in the temperature of the compressed gas. This will not only increase energy consumption during compression but may also cause decomposition or polymerization reactions of some components in the gas. Furthermore, the high temperature will accelerate the aging and damage of equipment components. Therefore, a three-stage progressive compression method is adopted, distributing the total compression ratio across three compression stages. The compression ratio of each stage is controlled within a reasonable range, and cooling equipment is installed after each compression stage to promptly remove the heat generated during compression.

[0062] The first-stage compression unit 31 has the largest intake volume, so it adopts a two-cylinder parallel structure. The two cylinders work synchronously to jointly undertake the compression task of the total intake volume. This parallel structure can reduce the piston speed of a single cylinder, reduce mechanical wear, and improve the system's processing capacity and operational reliability. The gas first enters the intake buffer tank, which can absorb the pulsating energy of the airflow, stabilize the intake pressure and flow, and prevent airflow pulsation from impacting the cylinders. The buffered gas is evenly distributed to the two parallel cylinders for compression. The compressed gas flows into the exhaust buffer tank, where the exhaust pressure is further stabilized before entering the cooler. The cooler cools the compressed high-temperature gas to below 40 degrees Celsius. Water vapor in the gas condenses into liquid water during the cooling process, and then enters the separator to separate and discharge the condensate.

[0063] After the first stage of compression and separation, the gas enters the second stage compression unit 32. The intake pressure and temperature of the second stage compression unit 32 are higher than those of the first stage, and the intake volume is relatively smaller, so a single-cylinder structure is adopted. The gas is also pressurized by the intake buffer tank before entering the cylinder for compression. After being compressed, the gas enters the third stage compression unit 33 after being processed by the exhaust buffer tank, cooler and separator.

[0064] The third-stage compression unit 33 is the final compression stage, which increases the gas pressure to a level that matches the downstream syngas pipeline network. After being stabilized by the inlet buffer tank, the gas enters the cylinder to complete the final compression. The compressed gas then enters the exhaust buffer tank for further stabilization. After eliminating airflow pulsation, the gas is directly connected to the plant's syngas pipeline network and transported as feed gas to the downstream chemical production sections.

[0065] Please see Figures 1-6 The workflow of this device covers four stages: device startup, normal continuous operation, automatic handling of abnormal conditions, and planned maintenance. Each stage is closely linked to achieve full recovery, graded purification, and continuous and stable operation of high-pressure flash steam from pulverized coal gasification.

[0066] I. Start-up preparations and water supply system establishment:

[0067] Before starting the unit, the status of all pipeline valves is first confirmed, ensuring that the drain valve is closed and all shut-off valves 542 are in normal flow condition. Then, the demineralized water booster pump group 5 is started. Under normal operating conditions, one booster pump is started first, while the other booster pump remains in hot standby mode with its inlet and outlet valves in the normally open position, ready for operation at any time. After the demineralized water is pressurized to 0.6 MPa by the booster pump, it is combined through parallel pipelines and then divided into two independent supply branches to deliver water to different heights of the scrubbing tower 1.

[0068] The bottom liquid level detection element collects the liquid level signal of the accumulation area in real time and transmits it to the intelligent control system. When the liquid level is lower than the set lower limit, the control system automatically opens the flow regulating valves 541 of the two water supply branches to increase the supply of washing water. When the liquid level rises to the set upper limit, the control system automatically opens the bottom drain valve to discharge excess dust-containing wastewater, ultimately stabilizing the bottom liquid level within the optimal operating range of 30% to 50%. Once the washing water circulation is stable and the bottom liquid level remains constant, high-pressure flash steam can be introduced for purification treatment.

[0069] II. Staged purification process within the high-pressure flash vapor tower:

[0070] The 0.5MPa high-pressure flash vapor produced by each high-pressure flash tank in the pulverized coal gasification workshop is collected through the main pipe and enters the gas phase inlet at the bottom of the scrubbing tower 1. The gas flows from bottom to top along the tower body and undergoes three stages of purification treatment in sequence.

[0071] The gas first comes into contact with the lower washing water spray area. A large flow of washing water is sprayed out from the inlet at the bottom of the tower, forming a dense countercurrent water curtain. At this point, the solid impurity content in the gas phase is the highest, mainly consisting of coarse coal ash particles with a diameter greater than 50μm and large droplets. These impurities are rapidly captured and dissolved after sufficient contact with the washing water. At the same time, the high-temperature flash vapor exchanges heat with the low-temperature washing water, and the temperature drops significantly. Most of the ammonia and water-soluble acidic impurities are also dissolved and absorbed in this process, completing the first stage of coarse purification.

[0072] The gas, after initial purification, continues to flow upwards, entering the multi-layered baffle structure region. Guided by the baffles, the airflow changes direction multiple times, significantly reducing its velocity. Medium-sized solid particles (20μm to 50μm in diameter) detach from the main airflow under the combined effects of gravity and inertia, settling downwards into the liquid accumulation area at the bottom of the tower. Simultaneously, the baffle structure prolongs the gas-liquid contact time, allowing for more thorough contact between incompletely collected impurities and the washing water, thus enhancing the purification effect.

[0073] After the gas rises to the middle of the tower, it comes into countercurrent contact with the finely atomized washing water sprayed from the upper washing water spray area. At this point, only a small amount of fine dust with a particle size between 10μm and 20μm and trace amounts of ammonium salt crystal particles remain in the gas phase. The washing water droplets with a higher degree of atomization can accurately capture these fine impurities, completing the second stage of fine purification.

[0074] The gas, after two stages of water washing, continues to flow upwards and enters the three-layer nested adjustable sieve packing assembly 4 at the top of the tower. The gas sequentially passes through the lower, middle, and upper packing layers, intercepting solid particles and droplets with diameters greater than 50 μm, 10 μm to 50 μm, and less than 10 μm, respectively, achieving three-stage gradient separation. The final purified gas has a dust content reduced to below 0.5 mg / Nm³ and flows out of the scrubbing tower 1 from the top gas phase outlet.

[0075] III. Gas-liquid separation and three-stage compression pressurization process:

[0076] The purified gas flowing out of scrubbing tower 1 first enters the first-stage gas-liquid separation device. After the gas enters the device, the flow cross-sectional area suddenly increases, the airflow velocity decreases significantly, and the larger free droplets naturally settle to the bottom of the device under the action of gravity; at the same time, the airflow changes its flow direction under the action of the internal baffles, and the droplets collide with the surface of the baffles due to inertial force and fall down, removing more than 90% of the free droplets in the gas phase.

[0077] After the first stage of separation, the gas enters the second stage of high-precision gas-liquid separation equipment. The micro-filter elements inside the equipment can intercept tiny droplets and solid particles with a diameter of less than 5μm that were not removed in the first stage, ensuring that the gas entering the compressor unit is clean and dry, and preventing liquid slugging and wear failures from the source.

[0078] The pre-treated gas sequentially enters the three-stage reciprocating compressor unit 3 for progressive pressurization. The first-stage compression unit 31 adopts a structure of two cylinders connected in parallel. The gas first enters the intake buffer tank, absorbs the energy of airflow pulsation, and stabilizes the intake pressure and flow rate before being evenly distributed to the two parallel cylinders for compression, raising the gas pressure to 1.2 MPa. The compressed high-temperature gas flows into the exhaust buffer tank for pressure stabilization, and then enters the cooler to be cooled to below 40°C. During this process, the water vapor in the gas condenses into liquid water, which is then separated and discharged by the separator.

[0079] After the first stage of compression and separation, the gas enters the second stage compression unit 32. After being stabilized by the intake buffer tank, it enters the cylinder and is compressed to 2.2MPa. The compressed gas also passes through the exhaust buffer tank, cooler and separator to remove condensate before entering the third stage compression unit 33.

[0080] The third-stage compression unit 33 is the final compression stage. After being stabilized by the inlet buffer tank, the gas enters the cylinder and is compressed to a pressure of 4.0 MPa, matching the downstream syngas pipeline network. The compressed gas then enters the exhaust buffer tank to eliminate airflow pulsation and is finally directly connected to the plant's syngas pipeline network, where it is transported as feed gas to downstream chemical production sections such as methanol synthesis, realizing the resource utilization of flash vapor.

[0081] IV. Intelligent Control System: Automatic Adjustment and Malfunction Handling

[0082] During operation, the intelligent control system collects signals from each detection element in real time and automatically adjusts the operating parameters according to preset logic to ensure stable operation of the device.

[0083] Pressure signals are collected in real time at pressure detection points at both ends of the tower to calculate the pressure difference inside the tower. When solid particles are deposited or ammonium salt crystals adhere to the surface of the packing layer, the gas flow channel narrows, and the pressure difference increases accordingly. When the pressure difference exceeds the set threshold of 5 kPa, the control system automatically starts the explosion-proof drive motor 49 at the top of the tower. The motor drives the middle cylinder 42 to rotate intermittently at a speed of 5 r / min. When the middle cylinder 42 rotates, the wavy curved surfaces on the contact surfaces of adjacent cylinders slide relative to each other, generating a periodic axial thrust, which pushes the upper and lower cylinders to make reciprocating micro-motions along the axis.

[0084] This movement alters the axial spacing of the three packing chambers, adjusting the packing compaction and sieve aperture to match the current dust content and gas volume of the flash vapor. Simultaneously, it generates axial micro-vibrations, causing the accumulated ash and ammonium salt crystals adhering to the packing surface to detach and flow downwards with the washing water into the bottom liquid collection chamber, ultimately being discharged with the dust-laden wastewater. When the pressure differential recovers to below 3 kPa, the control system automatically stops the drive motor 49.

[0085] When a booster pump experiences a motor overload, mechanical seal leakage, or abnormal pressure, the control system immediately triggers interlock protection, automatically closing the inlet and outlet valves of the faulty pump and simultaneously starting the hot standby booster pump. The entire switching process is completed within 10 seconds, ensuring uninterrupted water supply for washing. When adjustments to the gasifier load cause changes in flash steam or dust content, the control system automatically adjusts the flow rates of the two water supply branches. Under high load and high dust conditions, the lower water supply flow rate is increased to enhance the coarse washing effect, while under low load conditions, the upper water supply flow rate is increased to improve the fine washing precision, achieving an optimal balance between washing effect and energy consumption.

[0086] V. Planned Maintenance Procedure:

[0087] When a production cycle is completed and packing needs to be replaced or equipment maintenance is required, first close the inlet valve of the high-pressure flash tank to cut off the gas supply. Release the remaining gas in the tower into the flare system through the vent valve, then purge the tower with nitrogen until the oxygen content is below 0.5%, meeting the safety maintenance requirements. Open the maintenance manhole at the top of the tower to remove the three-layer nested adjustable sieve packing assembly 4 for cleaning, replacement, or maintenance. After maintenance, reinstall the packing assembly into the tower, close the maintenance manhole, and perform another nitrogen purging. Once successful, the unit can be restored to normal operation according to the startup procedure.

[0088] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A recovery device for pulverized coal gasification processing, characterized in that: The system includes a scrubbing tower (1), the inlet (13) of which is connected to the main outlet (6) of the high-pressure flash tank of pulverized coal gasification, the outlet (14) of which is connected in sequence to a gas-liquid separation unit (2) and a three-stage reciprocating compressor unit (3), the outlet of which is connected to a syngas pipeline network, and an adjustable sieve packing assembly (4) installed on the top of the scrubbing tower (1). The adjustable sieve packing assembly (4) includes three cylinders coaxially stacked, and the contact surfaces of two adjacent cylinders are machined with mutually matching wavy meshing surfaces (45). A drive motor (49) is installed on the outside of the scrubbing tower (1), and the output end of the drive motor (49) is connected to the cylinder located in the middle.

2. The recovery device for pulverized coal gasification processing according to claim 1, characterized in that: The three cylinders are a lower cylinder (41), a middle cylinder (42), and an upper cylinder (43). The upper and lower end faces of the upper cylinder (43) and the lower cylinder (41) are provided with perforated partition mesh (44) that matches the inner diameter of the corresponding cylinder. The lower cylinder (41) is filled with large-aperture grid filler (46), the middle cylinder (42) is filled with perforated plate corrugated filler (47), and the upper cylinder (43) is filled with high-efficiency wire mesh defoaming filler (48).

3. The recovery device for pulverized coal gasification processing according to claim 1, characterized in that: The drive motor (49) is an explosion-proof magnetic drive motor. The output shaft of the drive motor (49) is fixedly connected to the rotating shaft of the middle cylinder (42) through a sealed transmission mechanism (491). The sealed transmission mechanism (491) is installed through the side wall of the washing tower (1).

4. The recovery device for pulverized coal gasification processing according to claim 1, characterized in that: It also includes a demineralized water booster pump set (5), which includes a first booster pump (51) and a second booster pump (52). The inlets of the first booster pump (51) and the second booster pump (52) share a demineralized water main pipe (53). The outlets of the first booster pump (51) and the second booster pump (52) are connected in parallel and then divided into two independent water inlet branches (54). Each of the two water inlet branches (54) is equipped with an independent flow regulating valve (541) and a shut-off valve (542).

5. The recovery device for pulverized coal gasification processing according to claim 4, characterized in that: The washing tower (1) has a low-level water inlet (11) at the lower part of its side wall and a high-level water inlet (12) at the middle part of its side wall. The two water inlet branches (54) are respectively connected to the low-level water inlet (11) and the high-level water inlet (12). The washing tower (1) has a multi-layer baffle tray located between the low-level water inlet (11) and the high-level water inlet (12) inside.

6. The recovery device for pulverized coal gasification processing according to claim 1, characterized in that: The gas-liquid separation unit (2) includes a primary gas-liquid separator (21) and a compressor (22) inlet fine separator. The inlet of the primary gas-liquid separator (21) is connected to the outlet (14) of the scrubbing tower (1) through a pipe. The gas phase outlet of the primary gas-liquid separator (21) is connected to the inlet of the compressor (22) inlet fine separator through a pipe.

7. The recovery device for pulverized coal gasification processing according to claim 6, characterized in that: The three-stage reciprocating compressor unit (3) includes a first-stage compression unit (31), a second-stage compression unit (32) and a third-stage compression unit (33) connected in series. The inlet of the first-stage compression unit (31) is connected to the gas phase outlet of the fine separator at the inlet of the compressor (22) through a pipeline.

8. The recovery device for pulverized coal gasification processing according to claim 7, characterized in that: The first-stage compression unit (31) includes a first-stage intake buffer tank, two parallel first-stage cylinders, a first-stage exhaust buffer tank, a first-stage cooler, and a first-stage separator connected in sequence. The second-stage compression unit (32) includes a second-stage intake buffer tank, a second-stage cylinder, a second-stage exhaust buffer tank, a second-stage cooler, and a second-stage separator connected in sequence. The third-stage compression unit (33) includes a third-stage intake buffer tank, a third-stage cylinder, and a third-stage exhaust buffer tank connected in sequence.

9. The recovery device for pulverized coal gasification processing according to claim 4, characterized in that: The washing tower (1) is equipped with a bottom level transmitter, a differential pressure transmitter, and a top temperature transmitter. The bottom level transmitter, the differential pressure transmitter, the top temperature transmitter, the demineralized water booster pump group (5), and the drive motor (49) are all electrically connected to the intelligent control system.

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