Coal tar residue, coal liquefaction pitch exhaust gas treatment equipment and process

Abstract

The present application relates to the field of separation treatment, and is specifically coal tar residue, coal liquefaction pitch tail gas treatment equipment and process, the equipment includes the front end air blower, the transfer tank, the condensation tower, the washing oil tower, the water washing tower, the transfer air blower, the filling tower, the adsorption tower and the chimney that are sequentially communicated by pipeline, let harmful substances such as heavy pitch smoke, medium tar mist, water-soluble polarity, acid-base gas, light VOCs in tail gas be gradient treatment, replace high-temperature catalytic combustion with normal temperature low-temperature physical absorption and chemical absorption, realize the staged reduction of pollutants through cascade processing, disperse the processing pressure and energy consumption, utilize the multi-stage buffer structure so that slight fluctuation in a single link does not cause great influence on the treatment effect of the whole system, and the transfer air blower is used to isolate the pressure gradient of the whole system, reduce the influence on the rear section caused by the front section due to processing fluctuation, and facilitate long-period stable operation.

Description

Technical Field

[0001] This invention relates to the field of separation and treatment, specifically to equipment and processes for treating coal tar residue and coal liquefaction pitch tail gas. Background Technology

[0002] Coal tar is one of the main products of coal pyrolysis. Depending on the temperature of the coal pyrolysis process, the obtained coal tar is usually divided into low-temperature coal tar (500-600℃), medium-temperature coal tar (700-900℃), and high-temperature coal tar (900-1100℃). Coal tar chemical and coking processes produce heavy residues containing asphalt. Reuse and purification processes use asphalt-containing hazardous wastes such as coal tar residue, coal liquefaction residue, and ash oil residue as raw materials. Through solvent extraction separation, heating fractionation coking, or pyrolysis dry distillation, the purification and resource utilization of asphalt are achieved.

[0003] Existing technologies typically treat waste gas through combustion. The treatment process includes pretreatment such as spraying and washing, as well as catalytic combustion. Therefore, the pretreatment is relatively light, causing the treatment pressure and energy consumption to be concentrated in the catalytic combustion part. Furthermore, there is no gradient treatment process, so if one stage of the treatment becomes blocked, another stage will be directly and significantly affected. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides equipment and process for treating tail gas from coal tar residue and coal liquefaction pitch. The equipment structure includes a front-end induced draft fan, a transfer tank, a condenser tower, an oil washing tower, a water washing tower, a transfer induced draft fan, a packed tower, an adsorption tower, and a chimney, all connected sequentially by pipelines. The inlet of the front-end induced draft fan is used to collect tail gas via a pipeline. The transfer tank is connected to the outlet of the front-end induced draft fan for tail gas transport and transfer. A group of several condenser towers are connected sequentially, with the inlet of the group connected to the outlet of the transfer tank and the outlet of the group connected to the inlet of the oil washing tower. The inlet of the water washing tower is connected to the outlet of the oil washing tower. The transfer induced draft fan is connected between the outlet of the water washing tower and the inlet of the packed tower. The diameter of the pipe at the outlet of the transfer induced draft fan is smaller than the diameter of the pipe at the inlet. A group of several packed towers are connected sequentially, with the outlet of the group connected to the inlet of the adsorption tower. The chimney is connected to the outlet of the adsorption tower. The packed tower includes a tower body, which comprises a bottom inlet, a contact section, and a spray section arranged sequentially upwards. The exhaust gas guided by the intermediate induced draft fan enters from the bottom inlet and passes upwards through the contact section and the spray section. The contact section includes packing material and a collection mechanism and a redistribution mechanism surrounding the side of the packing material. The collection mechanism includes a receiving ring groove with an opening at the top and a side flow wall near the outer side of the tower body. The side flow wall is connected to the inner wall of the tower body below the spray section. The redistribution mechanism includes several liquid distribution pipes connected to the receiving ring groove. Several spray distribution mechanisms are provided on the liquid distribution pipes to form a spray area on the side of the packing material. The area formed by the packing material has a spray-facing surface on the top and side surfaces.

[0005] Furthermore, the receiving ring groove is annular and fixedly located at the top of the packing. The collecting mechanism also includes several connecting pipes, which are fixedly connected to the bottom of the receiving ring groove. The redistribution mechanism includes several receiving and storing pipes, which are fixedly connected downward at regular intervals on the connecting pipes. The bottom end of the receiving and storing pipes is fixed and connected to the distributing pipes to guide the liquid in the connecting pipes into the distributing pipes. The receiving and storing pipes and the distributing pipes extend in an arc shape along the side of the contact portion, and the receiving and storing pipes and the distributing pipes on the several connecting pipes surround and cover the side of the contact portion.

[0006] Furthermore, the cross-section of the lower connecting pipe is elongated, and the liquid receiving pipe has a liquid receiving trough fixed at one end connected to the lower connecting pipe. The top of the liquid receiving pipe is closed, while the top of the liquid receiving trough has an open opening. The outer wall of the lower connecting pipe is connected to the side flow wall, and the end of the liquid receiving trough near the outer wall of the lower connecting pipe is connected to the outer wall. The lower connecting pipe is divided into several equal parts along its length according to the number of liquid receiving troughs, and the length of the liquid receiving troughs increases progressively from top to bottom in multiples of the number of parts.

[0007] Furthermore, the bottom end of the liquid distribution pipe extends downwards and is provided with several end water bags. The spray distribution mechanism is fixed on the end water bags. The spray distribution mechanism includes a water storage spray group and a two-diaphragm-one-pressure valve. The water storage spray group is connected to the end water bags for quantitative storage of liquid for single spraying. The horizontal height of the bottom end of the water storage spray group is lower than the horizontal height of the bottom end of the end water bags. The water storage spray group includes a horizontally arranged storage pipe, a lower guide pipe connected to the bottom end of the storage pipe, and a side spray head fixedly installed at the front end of the lower guide pipe. The side spray head points towards the packing material in the middle on the side of the contact part.

[0008] Furthermore, the injection distribution mechanism also includes a middle section, with a water inlet at the front end of the end water tank, and a water-blocking baffle mounted on the water inlet. The middle section is shell-shaped and fixedly covers the end water tank outside the water inlet. The water storage injection group is fixed on the middle section and connected to the water inlet of the end water tank through the middle section. The two-isolation-one-pressure valve is fixed on the middle section and connected to the water storage injection group through the middle section. The two-isolation-one-pressure valve is connected to a gas pressure distribution pipe, which is connected to an external gas supply device to supply pressure to the two-isolation-one-pressure valve. The two-isolation-one-pressure valve is used to provide gas pressure to the water storage injection group and drive the water-blocking baffle to close the water inlet.

[0009] Furthermore, the two-part pressure valve includes a valve housing fixed to the middle section, a limiting tube fixed inside the valve housing, and a telescopic tube slidably nested on the limiting tube. Magnetic suction plates are fixed on both sides inside the valve housing, dividing the space inside the valve housing into an air inlet chamber and a movable chamber. A return spring is nested between the limiting tube and the telescopic tube. The return spring is located in the movable chamber and provides elastic force to the telescopic tube in the direction of the air inlet chamber. Several air outlets are opened in the middle section of the telescopic tube. The air outlets are located inside the limiting tube and move into the middle section as the telescopic tube moves towards the middle section. The tail end of the telescopic tube is located inside the middle section, and a laterally extending first pressure baffle is fixed at the tail end of the telescopic tube. The movement path of the first pressure baffle intersects with the water-blocking baffle.

[0010] Furthermore, the top of the middle section has a double cavity, and the top of the middle section has a near exhaust port. The near exhaust port is connected to the outside of the injection distribution mechanism. A plug is movably installed inside the near exhaust port. An airbag is fixed to the bottom of the plug and placed inside the double cavity. A guide frame is fixed to the top of the plug and is slidably engaged inside the near exhaust port. The buoyancy of the liquid in the double cavity on the airbag is greater than the sum of the weights of the plug, the guide frame, and the airbag.

[0011] Furthermore, the telescopic tube has side wings fixed on both sides of its head for engaging with the magnetic suction plate. The distance between the side wings and the air outlet along the axial direction of the telescopic tube is greater than or equal to the distance between the magnetic suction plate and the outer edge of the limiting tube. The telescopic tube has a vertically extending second pressure plate fixed at its tail end, and the movement path of the second pressure plate intersects with the airbag.

[0012] Furthermore, the packing material is a disc-shaped, regularly stacked packing material, and the packing material is composed of several longitudinally arranged corrugated plates. The packing material has folded side windows on its side, which are used to expose the gaps between the corrugated plates to the side and form a shower-facing surface.

[0013] This invention also provides a process for treating coal tar residue and coal liquefaction pitch tail gas, comprising the following steps: Step 1: Collection and buffering. The exhaust gas is introduced into the transfer tank by the front-end exhaust fan to homogenize and buffer the airflow to eliminate pipeline pressure fluctuations, and large particles of asphalt droplets and dust in the exhaust gas are removed by gravity settling. Step 2: Condensation and cooling to remove heavy oil. The exhaust gas comes out of the transfer tank and passes through multiple condensation towers connected in series to cool down the exhaust gas, treating most of the high-boiling-point heavy asphalt fumes and moisture, condensing them into liquid and discharging them. Step 3: The tail gas exits from the condenser and enters the washing tower for countercurrent spraying to remove tar mist, naphthalene, and some medium- and high-boiling-point aromatic VOCs that have not been completely condensed. Step 4: Wash away water-soluble substances and cut off oil. The exhaust gas comes out of the washing tower and enters the spray tower for clean water spraying to treat water-soluble substances such as ammonia and trace phenols, and to cut off the wash oil droplets carried out by the airflow. Step 5: Mid-section relay pressurization. The intermediate induced draft fan is used for relay pressurization to maintain negative pressure collection in the first half of the system and provide penetration power for the later section. The pressurized exhaust gas enters the three sets of filling towers in sequence. Step 6: Three-tower series fine washing. The exhaust gas enters three sets of packed towers in sequence. The first tower is sprayed with acidic solution for acid washing, the second tower is sprayed with alkaline solution for alkaline washing or sprayed with organic solution for absorption, and the third tower is sprayed with clean water or washing liquid. Then the exhaust gas enters the activated carbon adsorption tower. Step 7: Activated carbon adsorption at the bottom. The exhaust gas enters the activated carbon adsorption tower, where it is finally intercepted by microporous physical adsorption. This process removes any remaining small amounts of low-boiling-point aromatic VOCs and residual odor molecules. The treated exhaust gas is then discharged through the chimney.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention sequentially sets up a condensation tower, an oil washing tower, a water washing tower, a packed tower, and an adsorption tower to treat harmful substances in the exhaust gas, such as heavy asphalt fumes, medium tar mist, water-soluble polar substances, acid and alkaline gases, and light VOCs, in a gradient manner. This tiered treatment achieves graded reduction of pollutants, disperses treatment pressure and energy consumption, and utilizes a multi-stage buffer structure to ensure that slight fluctuations in a single stage will not significantly affect the overall system's treatment effect. At the same time, a transfer fan is used to isolate the pressure gradient of the entire system, reducing the impact of upstream treatment fluctuations on downstream processes and facilitating long-term stable operation.

[0015] Furthermore, this invention incorporates a collection mechanism, a redistribution mechanism, and a spray distribution mechanism surrounding the packing within the packed tower. This utilizes the sideflow generated by the spray, allowing the spray surface to cover the sides of the packing. This enables the treatment liquid to contact a portion of the packing in the opposite direction to the top spray surface, thereby assisting the top spraying operation in cleaning the packing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall treatment line of the coal tar residue and coal liquefaction pitch tail gas treatment equipment of the present invention.

[0017] Figure 2 This is a flowchart of the coal tar residue and coal liquefaction pitch tail gas treatment equipment of the present invention.

[0018] Figure 3 This is a three-dimensional structural diagram of the filling tower of the processing equipment of the present invention.

[0019] Figure 4 This is a frontal cross-sectional view of the filling tower and a partial frontal cross-sectional view of the collection mechanism of the present invention.

[0020] Figure 5 This is a three-dimensional exploded structural diagram of the packing material of the present invention in conjunction with the collection mechanism and the redistribution mechanism.

[0021] Figure 6 This is a three-dimensional structural diagram of the cooperation between the collection mechanism, redistribution mechanism and spray distribution mechanism of the present invention.

[0022] Figure 7 This is a three-dimensional structural diagram of the cooperation between the lower through pipe and the liquid receiving tank of the present invention, and a partial three-dimensional diagram of the cooperation between the spray distribution mechanism and the liquid distribution pipe.

[0023] Figure 8 This is a three-dimensional exploded view of the injection distribution mechanism of the present invention.

[0024] Figure 9 This is a three-dimensional structural diagram of the water storage jet assembly and the two-diaphragm-one-pressure valve in conjunction with the middle section of the present invention.

[0025] Figure 10 These are top view and full cross-sectional view of the spray distribution mechanism of the present invention.

[0026] In the diagram: 1. Front-end induced draft fan; 2. Transfer tank; 3. Condensation tower; 4. Oil washing tower; 5. Water washing tower; 6. Transfer induced draft fan; 7. Packed tower; 8. Adsorption tower; 9. Chimney; 71. Tower body; 72. Underground compartment; 73. Packing material; 74. Top liquid distribution pipe; 75. Demister; 76. Collection mechanism; 77. Redistribution mechanism; 78. Spray distribution mechanism; 79. Inner diaphragm; 711. Bottom Inlet; 712. Contact Part; 713. Spray Part; 714. Air Inlet; 715. Air Outlet; 731. Folded Side Window; 741. Top Spray Head; 761. Receiving Ring Groove; 762. Lower Connecting Pipe; 771. Liquid Storage Pipe; 772. Liquid Distribution Pipe; 773. Liquid Receiving Tank; 774. End Water Jack; 775. Main Air Pressure Pipe; 781. Water Storage and Spray Assembly; 782. Two-Isolation-One-Pressure Valve; 783. Middle Section; 784. Air Pressure Distribution Pipe; 7611, Side flow wall; 7612, Overflow baffle; 7621, Diverter wall; 7711, End outlet; 7721, Inlet interface; 7741, Water inlet; 7742, Water-proof baffle; 7811, Storage pipe; 7812, Lower inlet pipe; 7813, Side spray head; 7821, Valve housing; 7822, Limiting pipe; 7823, Magnetic suction plate; 7824, Telescopic pipe; 7825, Side wing; 7826, Air outlet; 7827, First pressure baffle; 7828, Second pressure baffle; 7829, Return spring; 7831, Second layer cavity; 7832, Near exhaust port; 7833, Plug; 7834, Airbag; 7835, Guide frame. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Examples, such as Figures 1-10 As shown: This invention provides a coal tar residue and coal liquefaction pitch tail gas treatment device. The device structure is formed by a continuous treatment line, which includes a front-end induced draft fan 1, a transfer tank 2, a condenser tower 3, an oil washing tower 4, a water washing tower 5, a transfer induced draft fan 6, a packing tower 7, an adsorption tower 8, and a chimney 9, all connected sequentially by pipelines. The inlet of the front-end induced draft fan 1 is used to collect tail gas through a pipeline. In this embodiment, the part of the plant that generates tail gas mainly includes a storage part, a transportation part, and a treatment part. The storage part outputs waste tail gas from the tank storing coal tar residue. The transportation part mainly outputs waste tail gas from transportation equipment such as a transport pump, a transport pipeline, and a bucket elevator. The treatment part includes equipment such as distillation treatment and centrifuge separation treatment to output waste tail gas. In this embodiment, the front-end induced draft fan 1 has three sets, each corresponding to one of the three parts that output waste tail gas. The front-end induced draft fan 1 drives the tail gas from the three parts to move from the inlet to the outlet. The transfer tank 2 is connected to the outlet of the front-end induced draft fan 1 for tail gas transportation and transfer. The condenser tower 3 consists of several connected in sequence as a group. In this embodiment, there are three condenser towers 3 connected in series as a group. The condenser tower 3 mainly cools down the waste gas and removes most of the high-boiling-point heavy asphalt fumes and moisture, condensing them into liquid and discharging them. The inlet of this group is connected to the outlet of the transfer tank 2, and the outlet of this group is connected to the inlet of the washing tower 4. The washing tower 4 removes the tar mist, naphthalene, and some medium and high-boiling-point aromatics that have not been completely condensed. The inlet of the water washing tower 5 is connected to the outlet of the washing tower 4. The water washing tower 5 sprays clean water to treat water-soluble substances such as ammonia and phenols, and intercepts the washing oil droplets carried out by the airflow. The intermediate induced draft fan 6 is connected between the outlet of the water scrubbing tower 5 and the inlet of the packed tower 7. It is used to supplement the treatment pressure in the middle stage. The water scrubbing tower 5 is placed in front of the intermediate induced draft fan 6, so as to form a water barrier by spraying water to prevent the intermediate induced draft fan 6 from igniting the equipment in front. The diameter of the pipe at the outlet of the intermediate induced draft fan 6 is smaller than the diameter of the pipe at the inlet. The packed tower 7 is composed of several connected in sequence to form a group. In this embodiment, there are three packed towers 7 connected in series to remove residual aromatics, acidic gases, polar organic compounds, benzene series and other light VOCs and acidic odor gases from the exhaust gas. The outlet of the packed tower 7 is connected to the inlet of the adsorption tower 8. After the previous multi-stage treatment, the remaining waste gas contains fewer harmful substances. The very small amount of low-boiling-point VOCs that escaped, such as benzene and toluene, are adsorbed by activated carbon, as well as residual odor molecules. The chimney 9 is connected to the outlet of the adsorption tower 8 to discharge the treated flue gas. If the discharge pressure at this point is insufficient, a fan similar to the destination and intermediate induced draft fan 6 can be added at the front end of the chimney 9 to supplement the pressure.

[0029] The filling tower 7 includes a tower body 71, with an underground chamber 72 fixed at the bottom. The underground chamber 72 is buried underground for liquid storage and transfer. The tower body 71 includes a bottom inlet 711, a contact section 712, and a spray section 713 arranged sequentially upwards. An air inlet 714 is fixed at the bottom inlet 711. The exhaust gas guided by the transfer blower 6 enters from the bottom inlet 711 and passes upwards through the contact section 712 and the spray section 713. The spray section 713 is fixed with a support, and a top liquid distribution pipe 74 is fixed on the support. Several downward-facing top spray heads 741 are fixed at the bottom of the top liquid distribution pipe 74 to form a liquid mist covering the top of the contact section 712. The top liquid distribution pipe 74 is connected to an external liquid supply mechanism. Different types of spray liquid are supplied by a pump according to the processing needs. An air outlet 715 is fixed at the top of the spray section 713. A demister 75 of the prior art is also fixed before entering the air outlet 715.

[0030] The contact portion 712 includes a packing material 73 and a collection mechanism 76 and a redistribution mechanism 77 surrounding the side of the packing material 73. An inner partition 79 is provided between the packing material 73 and the redistribution mechanism 77 to distinguish the inner and outer spaces. The redistribution mechanism 77 is provided with several spray distribution mechanisms 78 to form a spray area on the side of the packing material 73. The area formed by the packing material 73 has a spray-facing surface on the top and side surfaces. In this embodiment, the packing material 73 is a disc-shaped, regularly stacked packing material 73 within the contact portion 712. The packing material 73 is composed of several longitudinally arranged corrugated plates, which contact the rising exhaust gas through bending. A folded side window 731 is provided on the side. The folded side window 731 is used to expose the gap between the corrugated plates to the side and form a shower surface. An opening is provided on the inner shroud 79. The inner shroud 79 forms an outwardly protruding slope structure around the opening. The slope structure is funnel-shaped and extends outward toward the spray distribution mechanism 78, so that the spray area formed by the spray distribution mechanism 78 at the opening covers the inner side of the packing 73. In this embodiment, since there are three packing towers 7 processing in sequence, in order to ensure the air volume and reduce the local pressure, the packing 73 can be arranged without staggering or staggered at a small angle, such as ±15° staggering.

[0031] The collection mechanism 76 includes a receiving annular groove 761 and a connecting pipe 762. The receiving annular groove 761 is annular and fixedly located at the top of the packing 73. The top of the receiving annular groove 761 has an opening, and a side flow wall 7611 is provided on the side near the outside of the tower body 71. The side flow wall 7611 is connected to the inner wall of the tower body 71 below the spray section 713. The sprayed liquid will form a side flow on the inner wall of the tower body 71. The side flow flows through the side flow wall 7611 into the receiving annular groove 761 for collection. Several downwardly extending connecting pipes 762 are fixedly connected to the bottom of 761. The two are fixed together by welding. The outer side wall of the connecting pipe 762 is provided with a flow-dividing wall 7621 and connected to the side flow wall 7611. In this embodiment, two connecting pipes 762 are symmetrically fixed and located on one side of the corrugated plate at the outermost edge of the packing 73. When the packing 73 is staggered at a small angle, the connecting pipes 762 can avoid or minimize the obstruction of the area where the folded side window 731 and the opening of the inner diaphragm 79 are located. The redistribution mechanism 77 includes several liquid receiving pipes 771, which are fixedly connected downward at regular intervals to the lower connecting pipe 762. The bottom end of the liquid receiving pipe 771 is provided with an end outlet 7711. The liquid distributing pipe 772 is provided with an inlet interface 7721 on the side near the end outlet 7711. The bottom end of the liquid receiving pipe 771 is fixed to the liquid distributing pipe 772 by welding, and the end outlet 7711 and the inlet interface 7721 are connected by welding to guide the liquid in the lower connecting pipe 762 into the liquid distributing pipe 772, and form a water-proof channel for natural water flow between the receiving ring groove 761, the lower connecting pipe 762, the liquid receiving pipe 771 and the liquid distributing pipe 772. It should be noted that the liquid receiving pipe 771 and the liquid dispensing pipe 772 extend in an arc shape along the side of the contact portion 712. On the two connecting pipes 762, the liquid receiving pipe 771 and the liquid dispensing pipe 772 are approximately semi-circular arcs. The liquid receiving pipe 771 and the liquid dispensing pipe 772 on the two connecting pipes 762 surround and cover the side of the contact portion 712. Furthermore, the cross-section of the connecting pipe 762 is elongated. The liquid receiving pipe 771 has a liquid receiving trough 773 welded and fixed at the end where it connects to the connecting pipe 762. The top of the liquid receiving pipe 771 is closed, while the top of the liquid receiving trough 773 has an open opening. The liquid receiving trough 773 is close to the connecting pipe. One end of the connecting pipe 762 is connected to the diversion wall 7621; the connecting pipe 762 is divided into several equal parts along its length according to the number of liquid receiving tanks 773. The length of the liquid receiving tanks 773 increases from top to bottom in multiples of the number of parts. For example, the length of the uppermost liquid receiving tank 773 is one part, and the lengths of the liquid receiving tanks 773 from top to bottom are one part, two parts, three parts, etc. Since the liquid source of the receiving ring 761 is mainly the side flow on the wall, dividing the connecting pipe 762 into parts according to the number of parts can make the amount of side flow on the wall received by each liquid receiving tank 773 similar. In this embodiment, a vertical overflow baffle 7612 is fixed near the lower connecting pipe 762 in the receiving ring groove 761 to store a certain amount of liquid in the receiving ring groove 761. Inclined plates of different inclinations can be fixed on the overflow baffle 7612 and point to several liquid receiving tanks 773 respectively. After overflowing, the liquid can be guided to each liquid receiving tank 773, which plays a certain role in distributing the water flow. Most of the liquid overflows into the uppermost liquid receiving tank 773 and the liquid receiving pipe 771 before flowing to the next level. An overflow baffle 7612 can also be fixed at the end outlet 7711 in the liquid receiving pipe 771.

[0032] For the spray distribution mechanism 78, the bottom end of the liquid distribution pipe 772 extends downward and is provided with several end water bags 774. The spray distribution mechanism 78 is fixed on the end water bags 774. The spray distribution mechanism 78 includes a middle section 783, a water storage spray group 781 and a two-diaphragm-one-pressure valve 782. The end water tank 774 has a water inlet 7741 at its front end. A water-proof baffle 7742 is mounted on the water inlet 7741 by a hinge. The inner side of the water-proof baffle 7742 is provided with a rubber pad or sealing ring to block the water inlet 7741 when the water-proof baffle 7742 covers the water inlet 7741. The middle section 783 is shell-shaped and welded to the end water tank 774 outside the water inlet 7741. The middle section 783 serves as a transfer chamber at the water inlet 7741. The water storage and spray assembly 781 is welded and fixed to the middle section 783 and the end water tank 774, and is connected to the end water tank 774 for quantitative storage of liquid for single spraying. The bottom of the water storage and spray assembly 781 is lower than the bottom of the end water tank 774. The water storage and spray assembly 781 includes a horizontally arranged storage pipe 7811, a lower pipe 7812 connected to the bottom of the storage pipe 7811, and a side spray head 7813 fixedly installed at the front end of the lower pipe 7812. A liquid level sensor is fixed at the top of the water storage and spray assembly 781 to detect whether there is enough liquid in the end water tank 774. A liquid level sensor is fixed at the rear end of the lower pipe 7812 for linkage with the liquid level sensor of the end water tank 774. The side spray head 7813 points to the packing 73 in the middle on the side of the contact part 712. The two-isolation-one-pressure valve 782 is fixed to the middle section 783 and the end water tank 774 by welding and is connected to the water storage and injection group 781 through the middle section 783. The two-isolation-one-pressure valve 782 is connected to the air pressure branch pipe 784. Several air pressure branch pipes 784 are led out and connected to the air pressure main pipe 775. The air pressure main pipe 775 is then connected to the external air supply equipment to supply pressure to the two-isolation-one-pressure valve 782. The two-isolation-one-pressure valve 782 is used to provide air pressure to the water storage and injection group 781 and drive the water isolation baffle 7742 to close the water inlet 7741. Specifically, the two-part pressure valve 782 includes a valve housing 7821 fixed on the middle section 783, a limiting tube 7822 fixed inside the valve housing 7821, and a telescopic tube 7824 slidably nested on the limiting tube 7822. Magnetic suction plates 7823 are fixed on both sides inside the valve housing 7821, and the magnetic suction plates 7823 divide the space inside the valve housing 7821 into an air inlet chamber and a movable chamber. The air inlet chamber is connected to the air pressure manifold 784. A commonly used threaded interface for air pipe connection is fixed at the top of the air chamber. The air pressure manifold 784 can be connected to the interface through a nut and sealed by a washer. A return spring 7829 is nested between the limiting tube 7822 and the telescopic tube 7824. The return spring 7829 is located in the movable chamber and provides elastic force to the telescopic tube 7824 in the direction of the air inlet chamber. A sealing ring is provided between the telescopic tube 7824 and the limiting tube 7822. Several air outlets 7826 are provided in the middle section of the telescopic tube 7824. When the pressure in the air inlet chamber increases, the pressure drives the movable part, i.e., the movable telescopic tube 7824, to extend outwards, i.e., towards the middle section 783. The air outlets 7826 are located within the limiting tube 7822 and move into the middle section 783 along with the movement of the telescopic tube 7824 towards the middle section 783. When the air outlets 7826 move to the middle section 783, the air pressure is stored. The injection pipe 7811 is pressurized, while the tail end of the telescopic pipe 7824 is located inside the middle section 783. The tail end of the telescopic pipe 7824 is fixedly provided with a laterally extending first pressure baffle 7827. The movement path of the first pressure baffle 7827 intersects with the water-blocking baffle 7742. When the telescopic pipe 7824 moves into the middle section 783, the first pressure baffle 7827 squeezes the water-blocking baffle 7742, thereby causing the water-blocking baffle 7742 to gradually cover. It can also be seen that when the water-blocking baffle 7742 is unfolded, it swings towards the two-part pressure valve 782.

[0033] In summary, during implementation, the exhaust gas enters the tower body 71 through the inlet 714 of the bottom inlet 711 and moves upward. The liquid supply mechanism supplies the treatment liquid into the top liquid distribution pipe 74, and the liquid mist is sprayed downward through the top spray head 741. The liquid mist at the edge washes the interior of the tower body 71, generating a side flow that flows downward along the inner wall of the tower body 71. It flows into the receiving ring groove 761 through the side flow wall 7611 connected to the tower body 71. Part of it is stored in the receiving ring groove 761, and part of it flows into the lower connecting pipe 762 through the diversion wall 7621. The treatment liquid flows into several liquid receiving tanks 773, thus being stored in the receiving liquid pipe 771 for buffering, and then gradually flows into the diversion pipe 772. When the inflow is large, the treatment liquid gradually fills several end water tanks 774. When the water level in the end water tanks 774 rises, it triggers the liquid level sensor of the storage pipe 7811, and at the same time, the lower inlet pipe 7812... The liquid level sensor also detects liquid, activating the two-part pressure valve 782 to extend the telescopic tube 7824 into the middle section 783. The first pressure baffle 7827 presses the water-blocking baffle 7742 to close the water inlet 7741. Simultaneously, pressurized gas enters the middle section 783 and the accumulator pipe 7811 to compress the liquid, causing it to spray out from the side spray head 7813 at the bottom. The liquid sprayed from several side spray heads 7813 enters the packing 73 from the side, flushing some areas of the packing 73 that are away from the shower surface. As the liquid gradually decreases in the accumulator pipe 7811, the air increases. Due to the space for compression, the required air pressure continuously increases. After the liquid level sensor in the lower pipe 7812 no longer detects liquid, the air supply is shut off. The reset spring 7829 drives the telescopic tube 7824 to reset, opening the water inlet 7741 and refilling the accumulator pipe 7811 with water, repeating the cycle.

[0034] In this embodiment, metal side wings 7825 are fixed on both sides of the head of the telescopic tube 7824 for engaging with the magnetic suction plate 7823. The distance between the side wings 7825 and the air outlet 7826 in the axial direction of the telescopic tube 7824 is greater than or equal to the distance between the magnetic suction plate 7823 and the outer edge of the limiting tube 7822. After the air outlet 7826 enters the middle section 783, the pressure supplied by the air pressure manifold 784 to the two-stage pressure valve 782 further increases. At this time, the telescopic tube 7824 may jump. The impact of the jumping can be reduced by the attraction between the side wings 7825 and the magnetic suction plate 7823. The reset effect can be guaranteed simply by setting the elastic force of the reset spring 7829 to be greater than the attraction force between the side wings 7825 and the magnetic suction plate 7823.

[0035] In this embodiment, the top of the middle section 783 is provided with a double cavity 7831, and the top of the middle section 783 is provided with a near exhaust port 7832. The near exhaust port 7832 is connected to the outside of the spray distribution mechanism 78. After the side spray head 7813 finishes spraying, the liquid flow re-enters the accumulator pipe 7811. The air in the accumulator pipe 7811 can enter the end water tank 774 through the water inlet 7741, and then rise through the liquid distribution pipe 772 to the storage pipe 771 for discharge. However, the discharge path is relatively long, and it is difficult to exchange when the liquid in the liquid distribution pipe 772 is sufficient. Therefore, it can be discharged through the near exhaust port 7832. The system discharges liquid into the exhaust port 7832. A plug 7833 is movable inside the exhaust port 7832, and an airbag 7834 is fixed to the bottom of the plug 7833. The airbag 7834 is placed in the secondary cavity 7831. A guide frame 7835 is fixed to the top of the plug 7833. The guide frame 7835 is slidably engaged in the exhaust port 7832. The buoyancy of the liquid in the secondary cavity 7831 on the airbag 7834 is greater than the sum of the weight of the plug 7833, the guide frame 7835 and the airbag 7834. This allows the airbag 7834 to rise when the liquid in the accumulator tube 7811 is full, and the plug 7833 is used to seal the exhaust port 7832. Meanwhile, a vertically extending second pressure plate 7828 is fixedly provided at the tail end of the telescopic tube 7824. The movement path of the second pressure plate 7828 intersects with the airbag 7834. A slot is provided at the bottom of the second cavity 7831 for the second pressure plate 7828 to move, as a second safety measure to ensure that the exhaust port 7832 can be closed in time. At the same time, the first pressure plate 7827 and the second pressure plate 7828 can serve as the limiting structure of the telescopic tube 7824.

[0036] This embodiment provides a process for treating coal tar residue and coal liquefaction pitch tail gas, including the following steps: Step 1: Collection and Buffering. The front-end exhaust fan uses a fan with an air volume of 18,000 m³ / h and a minimum total pressure of 1200 Pa. The exhaust gas is introduced into the transfer tank by the front-end exhaust fan to homogenize and buffer the airflow to eliminate pipeline pressure fluctuations. Large particles of asphalt droplets and dust in the exhaust gas are removed by gravity settling. The transfer tank can be selected according to the actual processing volume and exhaust gas residence time requirements. In this embodiment, a tank with a volume of 30 m³ is used. Step 2: Condensation and cooling to remove heavy oil. A DN700 pipeline is used to lead the transfer tank out, with a flow velocity of 10~15m / s inside the pipeline. The exhaust gas comes out of the transfer tank and passes through multiple condensing towers connected in series to cool down the exhaust gas, treating most of the high-boiling-point heavy asphalt fumes and moisture. The heat exchange area of ​​a single condensing tower is 80~120m², reducing the exhaust gas temperature from 150°C to 40°C and removing 40%-70% of the total tar, condensing it into liquid for discharge. Each condensing tower is equipped with a liquid collection hopper and a drain valve at the bottom for tar recovery. The heat exchange area of ​​the first condenser is greater than or equal to the heat exchange area of ​​the subsequent condensers. Step 3: Tar removal through washing oil absorption. The tail gas exits from the condenser and enters the washing oil tower for countercurrent spraying. Utilizing the principle of "like dissolves like," it treats the remaining tar mist, naphthalene, and some medium- and high-boiling-point aromatic VOCs. As those skilled in the art will know, the washing oil tower can be a simple spray tower or a packed tower. In this embodiment, a tower body with a diameter of 2000mm is used, the empty tower gas velocity is conservatively set at 0.8m / s, and the liquid-to-gas ratio is at least 8L / m³. A large amount of washing oil is pumped for spraying, with a spraying pressure of 0.4~0.6MPa and an effective tower height of 4~6m. At the same time, the gas-liquid contact time is controlled to be ≥4s. Step 4: Wash away water-soluble substances and cut off oil. The tail gas exits from the oil washing tower and enters the spray tower for clean water spraying to treat ammonia, trace phenols, some water-soluble VOCs and other water-soluble substances, and to cut off the wash oil droplets carried out by the airflow. The size of this tower can be the same as that of the oil washing tower, and the liquid-to-gas ratio should be at least 2L / m³. The liquid-to-gas ratio is less than that of the oil washing tower, and the main purpose is washing and cooling. Step 5: Mid-section relay pressurization. Before the system reaches its maximum pressure loss section in several packed towers, relay pressurization is carried out through a transfer induced draft fan to overcome the resistance in the front section, maintain negative pressure collection in the first half of the system, and provide penetration power for the rear section. Here, the gas is "pushed" into the rear section. If the power of the front-end induced draft fan is redundant, the same configuration as the front-end induced draft fan can be used. The pressurized exhaust gas enters the three sets of packed towers in sequence. Step 6: Three towers in series for fine washing. The tail gas enters three sets of packed towers in sequence. The first tower is sprayed with acidic solution for acid washing. The exhaust gas generated by coal tar residue and coal liquefaction asphalt waste contains a lot of ammonia. The first tower uses acid washing to treat the ammonia part first. If the second tower is to use oil washing spray in the future, the formation of an alkaline environment by ammonia can be avoided. The second tower is sprayed with an alkaline solution for alkaline washing or with an organic solution for absorption. The decision is based on the pressure of the upstream washing tower. If the amount of oil washed by the upstream washing tower is relatively small in this process, the second tower in the packed tower will be sprayed with washing oil to further absorb aromatics and VOCs. If the amount of oil washed by the upstream washing tower is large, the second tower will use a 2-6% NaOH solution for alkaline washing and neutralization to remove residual hydrogen sulfide, sulfur dioxide, and acidic gases. The third tower is sprayed with clean water or washing liquid. If the second tower uses alkaline washing, the third tower uses a mixed washing solution of sodium hydroxide and sodium hypochlorite to deeply oxidize and decompose the aromatic VOCs, malodorous substances and other recalcitrant organic matter that were not removed in the first two stages. The underground chamber at the bottom of the tower is usually equipped with an online pH meter and an oxidation-reduction potential controller. When the pH value or ORP value is lower than the set range, the system will automatically replenish sodium hydroxide and sodium hypochlorite to ensure the best oxidation efficiency and stable treatment effect. If the second tower uses oil washing spray, the third tower uses clean water washing to intercept absorbent droplets, residual particles and adjust humidity. Then the exhaust gas enters the activated carbon adsorption tower. Step 7: Activated carbon adsorption at the bottom. The exhaust gas enters the activated carbon adsorption tower, where it is finally intercepted by microporous physical adsorption. This process treats the small amount of low-boiling-point VOCs and residual odor molecules that have escaped. The activated carbon loading is at least 2 tons, and the carbon layer height is at least 1 meter. Those skilled in the art can select the tower size of the activated carbon adsorption tower based on these parameters. Finally, the treated exhaust gas is discharged through a chimney with a height greater than 15 meters.

[0037] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A treatment device for coal tar residue and coal liquefaction pitch tail gas, characterized in that: The system includes a front-end induced draft fan, a transfer tank, a condenser tower, an oil washing tower, a water washing tower, a transfer induced draft fan, a filling tower, an adsorption tower, and a chimney, all connected sequentially via pipelines. The inlet of the front-end induced draft fan is used to collect exhaust gas through a pipeline. The transfer tank is connected to the outlet of the front-end induced draft fan for exhaust gas transportation and transfer. Several condenser towers are connected sequentially to form a group. The inlet of the first condenser tower in each group is connected to the outlet of the transfer tank. The outlet of the last condenser tower in each group is connected to the inlet of the oil washing tower. The inlet of the water washing tower is connected to the outlet of the oil washing tower. The intermediate induced draft fan is connected between the outlet of the water washing tower and the inlet of the packed tower. The diameter of the pipe at the outlet of the intermediate induced draft fan is smaller than the diameter of the pipe at the inlet. The packed tower consists of several connected in sequence as a group. The outlet of this group is connected to the inlet of the adsorption tower, and the chimney is connected to the outlet of the adsorption tower. The packed tower includes a tower body, which includes a bottom inlet section, a contact section, and a spray section arranged sequentially upwards. The exhaust gas guided by the intermediate induced draft fan enters from the bottom inlet section and passes upwards through the contact section and the spray section. The contact section includes packing material and a collection mechanism and a redistribution mechanism surrounding the side end of the packing material. The collection mechanism includes a receiving ring groove with an opening at the top and a side flow wall on the side near the outside of the tower body. The side flow wall is connected to the inner wall of the tower body below the spray section. The redistribution mechanism includes several liquid distribution pipes connected to the receiving ring groove. Several spray distribution mechanisms are provided on the liquid distribution pipes to form a spray area on the side of the packing material. The area formed by the packing material has a spray-facing surface on the top and side. The bottom end of the separator tube extends downward and is provided with several end water bags. The spraying and distributing mechanism is fixed on the end water bags. The spraying and distributing mechanism includes a water storage and spraying group and a two-diaphragm and one-pressure valve. The water storage and spraying group is connected to the end water bags and is used to quantitatively store the liquid for single spraying. The horizontal height of the bottom of the water storage jet assembly is lower than the horizontal height of the bottom of the end water tank. The water storage and spraying assembly includes a horizontally arranged storage pipe, a lower lead pipe connected to the bottom end of the storage pipe, and a side spray head fixedly installed at the front end of the lower lead pipe. The side spray head has a side contact portion pointing towards the middle of the packing material. The injection distribution mechanism also includes a middle section, with a water inlet at the front end of the end water tank. A water-blocking baffle is swung on the water inlet. The middle section is shell-shaped and is fixedly covered on the end water tank outside the water inlet. The water storage and jetting assembly is fixed on the middle section and connected to the water inlet of the end water tank through the middle section. The two-diaphragm-one-pressure valve is fixed on the middle section and connected to the water storage and jetting assembly through the middle section. The two-diaphragm-one-pressure valve is connected to the air pressure distribution pipe. The air pressure distribution pipe is connected to the external air supply equipment to supply pressure to the two-diaphragm-one-pressure valve. The two-diaphragm-one-pressure valve is used to provide air pressure to the water storage and jetting assembly and drive the water baffle to close the water inlet. The two-part pressure valve includes a valve body fixed on the middle section, a limiting tube fixed inside the valve body, and a telescopic tube slidably nested on the limiting tube. Magnetic suction plates are fixed on both sides inside the valve body, and the space inside the valve body is divided into an air intake chamber and a movable chamber by the magnetic suction plates. A return spring is nested between the limiting tube and the telescopic tube. The return spring is located in the movable chamber and provides elastic force to the telescopic tube in the direction of the air intake chamber. Several air outlets are provided in the middle section of the telescopic tube. The air outlets are located inside the limiting tube and move into the middle section as the telescopic tube moves towards the middle section. The tail end of the telescopic pipe is located inside the middle section, and a first pressure baffle plate extending laterally is fixedly installed at the tail end of the telescopic pipe. The movement path of the first pressure baffle plate intersects with the water-proof baffle plate.

2. The coal tar residue and coal liquefaction pitch tail gas treatment equipment according to claim 1, characterized in that: The receiving ring groove is annular and fixed at the top of the packing. The collecting mechanism also includes several lower connecting pipes, which are fixedly connected to the bottom of the receiving ring groove. The redistribution mechanism includes several liquid receiving pipes, which are fixedly connected to the lower connecting pipes at regular intervals downwards. The bottom end of the liquid receiving pipes is fixed and connected to the liquid distribution pipe to guide the liquid in the lower connecting pipe to the liquid distribution pipe. The liquid receiving tube and the liquid dispensing tube extend in an arc shape along the side of the contact part, and the liquid receiving tube and the liquid dispensing tube on several connecting tubes surround and cover the side of the contact part.

3. The coal tar residue and coal liquefaction pitch tail gas treatment equipment according to claim 2, characterized in that: The cross-section of the lower connecting pipe is long and narrow. The liquid receiving pipe has a liquid receiving tank fixed at one end that is connected to the lower connecting pipe. The top of the liquid receiving pipe is closed, while the top of the liquid receiving tank has an open opening. The outer wall of the lower connecting pipe is connected to the side flow wall, and the end of the liquid receiving tank near the outer wall of the lower connecting pipe is connected to the outer wall. The connecting pipe is divided into several equal parts along its length according to the number of liquid receiving tanks, and the length of the liquid receiving tanks increases from top to bottom in multiples of the number of parts.

4. The coal tar residue and coal liquefaction pitch tail gas treatment equipment according to claim 1, characterized in that: The top of the middle section has two cavities, and the top of the middle section has a near exhaust port. The near exhaust port is connected to the outside of the injection distribution mechanism, and a plug is movable inside the near exhaust port. An airbag is fixed to the bottom of the plug, and the airbag is placed in the second cavity. A guide frame is fixed to the top of the plug, and the guide frame slides and engages in the vicinity of the exhaust port. The buoyancy of the liquid in the second cavity on the airbag is greater than the sum of the weights of the plug, the guide frame and the airbag.

5. The coal tar residue and coal liquefaction pitch tail gas treatment equipment according to claim 4, characterized in that: Side wings are fixed on both sides of the head of the telescopic tube for attracting the magnetic plate. The distance between the side wings and the air outlet along the axial direction of the telescopic tube is greater than or equal to the distance between the magnetic plate and the outer edge of the limiting tube. A second pressure plate extending vertically is fixed at the tail end of the telescopic tube, and the movement path of the second pressure plate intersects with the airbag.

6. The coal tar residue and coal liquefaction pitch tail gas treatment equipment according to claim 1, characterized in that: The packing material is a disc-shaped, regular packing material that is regularly stacked in the contact area. The packing material is composed of several longitudinally arranged corrugated plates. The side of the packing material is provided with a folded side window, which is used to expose the gap between the corrugated plates to the side and form a shower-facing surface.

7. A process for treating tail gas from coal tar residue and coal liquefaction pitch, characterized in that: The treatment of coal tar residue and coal liquefaction pitch tail gas using the equipment described in any one of claims 1-6 includes the following steps: Step 1: Collection and buffering. The exhaust gas is introduced into the transfer tank by the front-end exhaust fan to homogenize and buffer the airflow to eliminate pipeline pressure fluctuations, and large particles of asphalt droplets and dust in the exhaust gas are removed by gravity settling. Step 2: Condensation and cooling to remove heavy oil. The exhaust gas comes out of the transfer tank and passes through multiple condensation towers connected in series to cool down the exhaust gas, treating most of the high-boiling-point heavy asphalt fumes and moisture, condensing them into liquid and discharging them. Step 3: The tail gas exits from the condenser and enters the washing tower for countercurrent spraying to remove tar mist, naphthalene, and some medium- and high-boiling-point aromatic VOCs that have not been completely condensed. Step 4: Wash away water-soluble substances and cut off oil. The tail gas comes out of the washing tower and enters the spray tower for clean water spraying to treat ammonia, trace amounts of water-soluble phenolic substances, and cut off the washing oil droplets carried out by the airflow. Step 5: Mid-section relay pressurization. The intermediate induced draft fan is used for relay pressurization to maintain negative pressure collection in the first half of the system and provide penetration power for the later section. The pressurized exhaust gas enters the three packing towers in sequence. Step 6: Three-tower series fine washing. The exhaust gas enters three packed towers in sequence. The first tower is sprayed with an acidic solution for acid washing, the second tower is sprayed with an alkaline solution for alkaline washing or sprayed with an organic solution for absorption, and the third tower is sprayed with clean water or washing liquid. Then the exhaust gas enters the activated carbon adsorption tower. Step 7: Activated carbon adsorption at the bottom. The exhaust gas enters the activated carbon adsorption tower, where it is finally intercepted by microporous physical adsorption. This process removes any remaining low-boiling-point substances and residual odor molecules. The treated exhaust gas is then discharged through the chimney.

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