Tail gas treatment device based on negative pressure suction

Abstract

The utility model discloses a tail gas treatment device based on negative pressure suction. The tail gas treatment device comprises a storage tank, the cryogenic oil gas treatment device is provided with a separation inlet, an exhaust port and a liquid discharge port; the mixing device is provided with a lean hydrocarbon inlet, an air inlet, a mixing outlet, a heat exchange inlet and a heat exchange outlet; the catalytic oxidation device is provided with a catalytic inlet and a catalytic outlet, and the catalytic outlet is communicated with the heat exchange inlet; and the conveying device comprises a driving mechanism and two conveying mechanisms and is used for introducing the outside air into the air inlet and inputting the hydrocarbon-lean gas into the hydrocarbon-lean inlet at the same time. According to the tail gas treatment device based on negative pressure suction, tail gas in the storage tank is introduced into the copious cooling oil gas treatment device through gas suction, hydrocarbon-poor gas is formed and then mixed with external air, then catalytic oxidation is conducted, generated high-temperature gas is used for preheating the hydrocarbon-poor gas and mixed gas, catalytic oxidation is promoted, meanwhile, environmental pollution is reduced, and the service life of the tail gas is prolonged. Heat energy generated by catalytic oxidation is fully utilized, and energy conservation and environmental protection are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to tail gas treatment technical field especially is tail gas treatment device based on negative pressure suction. BACKGROUND

[0002] The storage tank is often used for temporarily storing some dangerous chemical materials, and needs to be cleaned to ensure normal use after a period of use.

[0003] However, during the storage of dangerous chemicals, some toxic and harmful tail gas may be produced in the storage tank. Therefore, in order to ensure safety, meet the requirements of the operating environment, and prevent chemical reactions, the gas in the storage tank needs to be ventilated and replaced. The tail gas produced after the storage tank is cleaned usually contains high concentrations of volatile organic compounds (VOCs), carbon monoxide (CO), and a small amount of residual hydrocarbon substances. If directly discharged, it will not only seriously pollute the environment, but also may cause safety hazards.

[0004] Therefore, there is an urgent need for a tail gas treatment device and method for a storage tank. UTILITY MODEL CONTENT

[0005] The utility model aims at overcoming the defects in the prior art, and provides a tail gas treatment device based on negative pressure suction, which is energy-saving and environmentally friendly, and reduces environmental pollution.

[0006] To solve the above technical problems, the utility model provides a tail gas treatment device based on negative pressure suction, which comprises:

[0007] The storage tank has a feed inlet, a discharge outlet and an air outlet, and the feed inlet, the discharge outlet and the air outlet are respectively connected with a feed valve, a discharge valve and an air valve;

[0008] The cryogenic oil and gas treatment device has a separation inlet, an air outlet and a liquid outlet, and the liquid outlet is connected with a liquid discharge valve;

[0009] The mixing device has a lean hydrocarbon inlet, an air inlet, a mixing outlet, a heat exchange inlet and a heat exchange outlet, and the lean hydrocarbon inlet is in communication with the air outlet;

[0010] The catalytic oxidation device has a catalytic inlet and a catalytic outlet, and the catalytic outlet is in communication with the heat exchange inlet;

[0011] The conveying device comprises a driving mechanism and two conveying mechanisms, and the driving mechanism is used for providing power to the two conveying mechanisms, so that one of the conveying mechanisms introduces external air into the air inlet at the same time that the other conveying mechanism inputs the lean hydrocarbon gas output by the air outlet into the lean hydrocarbon inlet, so as to mix the lean hydrocarbon tail gas with the external air.

[0012] Preferably, in order to realize continuous gas delivery, the two delivery mechanisms each comprise two delivery units opposite to each other, each of the two delivery units comprises a cylinder and a piston axially and sealingly connected with the inner wall of the cylinder, the cylinder is provided with an inlet and an outlet, the inlet and the outlet are connected with two one-way valves opposite in direction, and the driving mechanism drives the pistons of the two delivery units of the delivery mechanism to move synchronously.

[0013] Preferably, in order to drive the pistons of the two delivery units to move synchronously, the driving mechanism comprises a driving unit, a rotating disc and two transmission units arranged on both sides of the rotating disc, the driving unit drives the rotating disc to rotate around its own axis, the two transmission units are arranged on both sides of the rotating disc and are respectively connected with the two delivery mechanisms, the two transmission units each comprise a convex shaft arranged on the rotating disc and spaced apart from the axis of the rotating disc and a moving frame sleeved outside the convex shaft, the moving frame is fixedly connected with the pistons of the two delivery units of the corresponding delivery mechanism, and the moving directions of the two moving frames are consistent with the distribution directions of the two delivery units of the delivery mechanism.

[0014] Preferably, in order to adjust the delivery ratio of air and lean hydrocarbon gas, ensure sufficient oxidation of the lean hydrocarbon gas, and avoid excessive delivery of air to affect the catalytic oxidation efficiency in the later stage, an adjusting unit is arranged between one of the convex shafts and the rotating disc to adjust the spacing between the convex shaft and the axis of the rotating disc, the other convex shaft is fixedly connected with the rotating disc, and the lean hydrocarbon inlet is connected with a flow sensor.

[0015] Preferably, in order to adjust the air delivery amount according to the amount of lean hydrocarbon gas, the adjusting unit comprises an adjusting motor arranged on the convex shaft, the adjusting motor is drivingly connected with a lead screw, the lead screw is threadedly connected with a sleeve, the convex shaft corresponding to the adjusting unit is fixed to the sleeve, and the rotating disc is provided with a distance sensor for detecting the position of the sleeve.

[0016] Preferably, in order to realize preheating of the lean hydrocarbon gas and the mixed gas, ensure that the mixed gas has a certain temperature after being discharged, and facilitate sufficient catalytic oxidation, the mixing device has a preheating cavity communicated with the air inlet and a heat exchange cavity communicated with the heat exchange outlet, a preheating coil is arranged in the preheating cavity, an output end of the preheating coil is communicated with the heat exchange cavity through a heat insulation pipe, an outer pipe is arranged in the heat exchange cavity, two ends of the outer pipe are respectively communicated with the heat insulation pipe and the heat exchange outlet, an inner pipe penetrates through the inner side of the outer pipe, and two ends of the inner pipe are respectively communicated with the lean hydrocarbon inlet and the preheating cavity.

[0017] Preferably, in order to realize sufficient preheating of the lean hydrocarbon gas, the outer pipe is densely arranged in the heat exchange cavity.

[0018] Preferably, in order to realize safe emission of the exhaust gas, the heat exchange outlet is arranged at the bottom of the mixing device and connected with a downward extending exhaust gas pipe, the bottom of the exhaust gas pipe is arranged in the waste liquid pool.

[0019] Preferably, in order to ensure that clean air can be introduced, and to avoid smoke in the air mixing with the lean hydrocarbon gas and affecting the operation of the device, a conveying mechanism corresponding to the air inlet is connected with a filter assembly at the input end.

[0020] In order to solve the above technical problems, the utility model also provides a tail gas treatment method based on negative pressure suction, comprising the following steps:

[0021] S100, discharging: discharging the liquid dangerous chemical in the storage tank;

[0022] S200, suction: introducing the tail gas in the storage tank into the cryogenic oil gas treatment device to discharge the lean hydrocarbon gas;

[0023] S300, mixing: introducing the external air and the lean hydrocarbon gas into the mixing device to mix and discharge the mixed gas;

[0024] S400, catalytic oxidation: catalytic oxidation of the mixed gas to discharge the high-temperature exhaust gas;

[0025] S500, flow guiding: introducing the exhaust gas into the mixing device to exchange heat with the external air and the lean hydrocarbon gas and then discharge to the outside;

[0026] The conveying mechanism used in step S200 for tail gas conveying and the conveying mechanism used in step 300 for external air conveying are driven to operate by the same driving mechanism.

[0027] Compared with the prior art, the tail gas treatment device based on negative pressure suction of the utility model introduces the tail gas in the storage tank into the cryogenic oil gas treatment device through suction, mixes the lean hydrocarbon gas with the external air after forming the lean hydrocarbon gas, and then catalytic oxidation, the high-temperature gas generated is used for preheating the lean hydrocarbon gas and the mixed gas, promotes catalytic oxidation while reducing environmental pollution, fully utilizes the heat energy generated by catalytic oxidation, realizes energy saving and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the structure schematic view of the utility model;

[0029] Figure 2 is the top view of the utility model;

[0030] Figure 3 is the structure schematic view of another view of the utility model;

[0031] Figure 4It is structural schematic view of filter assembly of the utility model;

[0032] Figure 5 It is Figure 4 sectional structure schematic view;

[0033] Figure 6 It is structural schematic view of conveying device of the utility model;

[0034] Figure 7 It is structural schematic view of another view angle of conveying device of the utility model;

[0035] Figure 8 It is Figure 7 explosion schematic view;

[0036] Figure 9 It is structural schematic view of fixed frame in conveying device of the utility model;

[0037] Figure 10 It is structural schematic view of conveying unit in conveying device of the utility model;

[0038] Figure 11 It is Figure 10 sectional structure schematic view;

[0039] Figure 12 It is structural schematic view of driving mechanism of the utility model;

[0040] Figure 13 It is Figure 12 explosion schematic view;

[0041] Figure 14 It is connecting structure schematic view of mixing device and waste liquid pool of the utility model;

[0042] Figure 15 It is Figure 14 explosion schematic view;

[0043] Figure 16 It is Figure 14 explosion schematic view of another view angle;

[0044] Figure 17 It is structural schematic view of mixing device of the utility model;

[0045] Figure 18 It is Figure 17 explosion schematic view;

[0046] Figure 19 It is Figure 18 explosion schematic view of another view angle;

[0047] Figure 20 It is Figure 17 sectional structure schematic view;

[0048] Figure 21 is Figure 20 an enlarged view of A part of Fig. 1;

[0049] Fig. 1 is a schematic diagram of the oil gas treatment device; Fig. 2 is a schematic diagram of the mixing device; Fig. 3 is a schematic diagram of the catalytic oxidation device; Fig. 4 is a schematic diagram of the driving mechanism; Fig. 5 is a schematic diagram of the conveying mechanism; Fig. 6 is a schematic diagram of the filter assembly; Fig. 7 is a schematic diagram of the waste liquid pool; Fig. 8 is a schematic diagram of the filter assembly; Fig. 9 is a schematic diagram of the fixed frame; Fig. 1: 1, storage tank; 11, feed inlet; 12, air outlet; 13, feed valve; 14, air valve; 15, discharge port; 16, discharge valve; 2, oil gas treatment device; 21, separation inlet; 22, exhaust port; 23, liquid discharge port; 24, liquid discharge valve; 3, mixing device; 301, lean hydrocarbon inlet; 302, air inlet; 3021, air inlet pipe; 303, mixing outlet; 304, heat exchange inlet; 305, heat exchange outlet; 3051, exhaust pipe; 306, flow sensor; 307, preheating cavity; 308, heat exchange cavity; 31, preheating coil; 32, outer tube; 33, inner tube; 34, support plate; 341, support foot; 35, heat insulation cover; 351, heat insulation pipe; 36, mixing box; 361, mixing cover; 3611, heat insulation outlet; 362, flow distribution plate; 363, air inlet cover; 364, flow guide cover; 37, heat exchange shell; 371, outer shell cover; 3711, heat insulation inlet; 372, outer shell cover; 373, inner shell cover; 374, inner shell cover; 375, closed channel; 376, exhaust cover; 38, partition plate; 4, catalytic oxidation device; 41, catalytic inlet; 42, catalytic outlet; 5, driving mechanism; 51, driving unit; 511, driving motor; 512, driving gear; 52, rotating disc; 521, support bearing; 53, transmission unit; 531, convex shaft; 532, moving frame; 533, connecting strip; 534, sliding sleeve; 54, adjusting unit; 541, adjusting motor; 542, screw rod; 543, screw sleeve; 544, distance sensor; 545, support sleeve; 6, conveying mechanism; 61, conveying unit; 611, cylinder; 6111, inlet; 6112, outlet; 612, piston; 613, one-way valve; 614, filter screen; 62, three-way pipe; 7, waste liquid pool; 71, waste discharge pipe; 72, waste discharge valve; 73, support inner frame; 74, outer frame; 75, sponge plate; 8, filter assembly; 81, filter barrel; 811, air inlet; 812, waste discharge port; 813, air inlet valve; 814, waste discharge valve; 815, inner convex ring; 82, filter cover; 821, air outlet; 822, positioning compression ring; 83, filter core; 831, outer flange; 84, bolt; 85, nut; 86, connecting hose; 87, collection box; 9, fixed frame; 91, bottom plate; 92, motor frame; 93, support; 94, cross frame; 95, frame; 951, cross strip; 952, vertical strip; 96, bearing frame. DETAILED DESCRIPTION

[0050] The specific embodiments of the present application will be further described in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0051] As Figures 1-21 shown, the utility model discloses a tail gas treatment device based on negative pressure suction, including:

[0052] The storage tank 1 has a feed inlet 11, a discharge outlet 15 and a gas suction port 12, and the feed inlet 11, the discharge outlet 15 and the gas suction port 12 are respectively connected with a feed valve 13, a discharge valve 16 and a gas suction valve 14.

[0053] The cryogenic oil and gas treatment device 2 has a separation inlet 21, an exhaust port 22 and a liquid discharge port 23, and the liquid discharge port 23 is connected with a liquid discharge valve 24.

[0054] The mixing device 3 has a lean hydrocarbon inlet 301, an air inlet 302, a mixing outlet 303, a heat exchange inlet 304 and a heat exchange outlet 305, and the lean hydrocarbon inlet 301 is communicated with the exhaust port 22.

[0055] The catalytic oxidation device 4 has a catalytic inlet 41 and a catalytic outlet 42, and the catalytic outlet 42 is communicated with the heat exchange inlet 304.

[0056] The conveying device includes a driving mechanism 5 and two conveying mechanisms 6, and the driving mechanism 5 is used to provide power to the two conveying mechanisms 6, so that one of the conveying mechanisms 6 introduces external air into the air inlet 302, and the other conveying mechanism 6 inputs the lean hydrocarbon gas output by the exhaust port 22 to the lean hydrocarbon inlet 301, so as to mix the lean hydrocarbon tail gas with the external air.

[0057] When the device is used, the storage tank 1 is used for temporarily storing hazardous chemicals, and by opening the feed valve 13, the liquid hazardous chemicals can enter the storage tank 1 through the feed inlet 11 for storage, and then the feed valve 13 is closed.

[0058] At this time, the conveying device is started, and the two conveying mechanisms 6 are driven to operate simultaneously by the driving mechanism 5. In order to distinguish the two conveying mechanisms 6, the two conveying mechanisms 6 are defined as a first conveying assembly and a second conveying assembly. The driving mechanism 5 drives the first conveying assembly and the second conveying assembly to operate simultaneously. The first conveying assembly extracts the residual tail gas in the storage tank 1, so that a negative pressure is formed in the storage tank 1. After the tail gas is discharged from the gas extraction port 12, the extracted tail gas is conveyed by the first conveying assembly to the inside of the cryogenic oil gas treatment device 2 through the separation inlet 21. The tail gas is subjected to condensation cooling treatment by the cryogenic oil gas treatment device 2, so that the VOCs components in the tail gas are liquefied and separated from the CO gas and other hydrocarbon substances. The accumulated VOCs substances can be discharged from the cryogenic oil gas treatment device 2 through the liquid discharge port 23 by opening the liquid discharge valve 24. The CO and other hydrocarbon substances combine to form a lean hydrocarbon gas, which is discharged from the gas discharge port 22 and then enters the mixing device 3 through the lean hydrocarbon inlet 301.

[0059] At the same time, the second conveying assembly operates to extract external air, which is conveyed to the mixing device 3 through the air inlet 302. In the mixing device 3, the external air is mixed with the lean hydrocarbon gas to form a mixed gas, which is discharged from the mixing outlet 303 and then enters the catalytic oxidation device 4 through the catalytic inlet 41. The catalytic oxidation device 4 of the utility model is a CO catalytic oxidation furnace, which is provided with a Pt-Pd / Al2O3 honeycomb catalyst layer and has a working temperature of 350-400 DEG C. When the device operates, the carbon monoxide can be catalytically oxidized to carbon dioxide, and the CO catalytic oxidation furnace is integrated with a regeneration module to realize self-cleaning of the catalyst.

[0060] After the mixed gas composed of the lean hydrocarbon gas and the external air is catalytically oxidized to carbon dioxide, the exhaust gas discharged from the catalytic outlet 42 has a high temperature, while the temperature of the lean hydrocarbon gas discharged from the gas discharge port 22 of the cryogenic oil gas treatment device 2 is reduced. By connecting the catalytic outlet 42 and the heat exchange inlet 304, the high-temperature gas generated after catalytic oxidation can enter the mixing device 3 to exchange heat with the lean hydrocarbon gas and the external air. On the one hand, the lean hydrocarbon gas and the external air can be heated to form a mixed gas with a higher temperature, which is introduced into the catalytic oxidation device 4 to facilitate catalytic oxidation of the carbon monoxide gas in the mixed gas. On the other hand, the temperature of the exhaust gas can be reduced after heat exchange, so that the exhaust gas is discharged to the outside after being cooled, thereby reducing environmental pollution and damage to the outside.

[0061] Therefore, after the above technology is used, the heat energy generated by catalytic oxidation can be fully utilized, the exhaust gas is discharged into the mixing device 3 to exchange heat with the low-temperature lean hydrocarbon gas and the external air, the temperature of the mixed gas is raised, the catalytic oxidation of the carbon monoxide gas in the mixed gas is promoted, meanwhile, the high-temperature exhaust gas is cooled, the white mist generated due to the large temperature difference with the outside environment during the exhaust gas discharge is reduced, the pollution hazard to the environment is reduced, energy saving and environmental protection are realized; in addition, in the utility model, one driving mechanism 5 can drive two conveying mechanisms 6 to operate synchronously, which are used for conveying two different gases, one of which is the tail gas extracted from the storage tank 1, and the other is the external air, compared with the prior art, the number of driving sources is reduced, the equipment cost is reduced, meanwhile, the device is more compact, the occupied space is reduced, and the increase of the device cost and the occupied space caused by the installation of two air pumps is avoided.

[0062] Further improvement is that the conveying mechanism 6 connected with the air inlet 302 is provided with a filtering assembly 8 connected with the input end.

[0063] The filtering assembly 8 can filter out the dust impurities in the external air, so that these impurities cannot enter the equipment pipeline and affect the normal operation of the device.

[0064] The specific structure of the filtering assembly 8 is shown in Figure 5 and Figure 6 The filtering assembly 8 comprises a filter barrel 81 which is open at the top and is fixed on the bottom surface through a support leg, an air inlet 811 is arranged on the side wall of the filter barrel 81, a waste discharge port 812 is arranged at the bottom, an air inlet valve 813 and a waste discharge valve 814 are connected with the air inlet 811 and the waste discharge port 812 respectively, a collecting box 87 which is open at the top is arranged directly below the waste discharge port 812, the top of the filter barrel 81 is detachably connected through a threaded bolt 84 and a nut 85 and is covered with a filter cover 82, an air outlet 821 is arranged on the filter cover 82, a connecting hose 86 is communicated with the air outlet 821, and the connecting hose 86 is connected with the air inlet end of the first conveying assembly.

[0065] The filter barrel 81 is provided with a filter core 83, specifically, an inner convex ring 815 which is coaxial with the filter barrel 81 and is located above the air inlet 811 is integrally connected with the circumferential inner wall of the filter barrel 81, the filter core 83 is open at the top, the circumferential outer edge of the filter core 83 is sealingly attached to the circumferential inner wall of the inner convex ring 815, an outward flange 831 is arranged on the circumferential outer edge of the top, a positioning pressure ring 822 is integrally connected below the filter cover 82, the circumferential outer edge of the positioning pressure ring 822 is sealingly connected with the circumferential inner wall of the filter barrel 81, and the outward flange 831 is clamped between the inner convex ring 815 and the positioning pressure ring 822.

[0066] After the above structure is adopted, the bolt 84 and the nut 85 are connected by threads, facilitating detachable connection of the filter barrel 81 and the filter cover 82, facilitating regular opening of the filter barrel 81 for cleaning and replacement of the filter element 83. During assembly, the filter cover 82 is fastened to the filter barrel 81 by the bolt 84 and the nut 85, and at the same time, the filter cover 82 is accurately docked with the filter barrel 81 by the positioning pressure ring 822, and the positioning pressure ring 822 tightly presses the outward flange 831 against the inner protruding ring 815 to fix the position of the filter element 83. During use of the filter assembly 8, the external dust-containing gas enters the filter barrel 81 through the air inlet 811, and the dust particles in the air are filtered out by the filter element 83, so that the clean air passes through the filter element 83 and is discharged from the air outlet 821, and then enters the first conveying assembly through the connecting hose 86. After being used for a period of time, the exhaust valve 814 connected to the exhaust port 812 can be opened, so that the dust particles deposited on the bottom of the filter barrel 81 can fall into the collection box 87 below through the ventilation pipe exhaust port 812, and then the exhaust valve 814 is closed to ensure a certain cleanliness inside the filter barrel 81, so as to avoid excessive dust particles in the filter barrel 81 from easily blocking the filter element 83.

[0067] Further improvement is that the two conveying mechanisms 6 each include two conveying units 61 opposite to each other, and each of the two conveying units 61 includes a cylinder barrel 611 and a piston 612 in sealing connection with the inner wall of the cylinder barrel 611 in an axial direction and in sliding fit, the cylinder barrel 611 is provided with an inlet 6111 and an outlet 6112, the inlet 6111 and the outlet 6112 are connected with two one-way valves 613 opposite in direction, and the driving mechanism 5 drives the pistons 612 of the two conveying units 61 in the conveying mechanism 6 to move synchronously.

[0068] As shown in Figs. Figure 7 and Figure 8 The conveying device further includes a fixing frame 9 fixed above the mixing device 3, and the fixing frame 9 is used to support the driving mechanism 5 and the two conveying mechanisms 6. The mixing device 3 is in the shape of a whole horizontal cuboid, the two conveying mechanisms 6 are distributed in a vertical direction, the first conveying assembly is located above the second conveying assembly, and the first conveying assembly and the second conveying assembly each include two conveying units 61 opposite to each other, and the distribution direction of the two conveying units 61 is parallel to the width direction of the mixing device 3.

[0069] The cylinder barrel 611 of each of the two conveying units 61 is fixed to the fixing frame 9 and has a length direction parallel to the width direction of the mixing device 3, the piston 612 includes a piston plate sealingly fitted with the circumferential inner wall of the cylinder barrel 611 and a piston shaft fixedly connected with the piston plate, the inlet 6111 and the outlet 6112 are both arranged at the end of the cylinder barrel 611 away from the other cylinder barrel 611, the other end of the cylinder barrel 611 is fixed with a filter screen 614, the piston shaft sealingly penetrates the filter screen 614, and the driving mechanism 5 is fixedly connected with the end of the piston shaft of the two conveying units 61 in the conveying mechanism 6.

[0070] Two conveying mechanisms 6 also each include two three-way pipes 62, for the upper first conveying assembly, two three-way pipes 62, one of which has three ends of one input end and two output ends, the input end is communicated with the connecting hose 86, and the two output ends are communicated with the conveying inlets 6111 of the two cylinder barrels 611 respectively, and the remaining one has three ends of one output end and two input ends, the two input ends are communicated with the conveying outlets 6112 of the two cylinder barrels 611 respectively, and the output end is communicated with the air inlet 302 of the mixing device 3, so that when the driving mechanism 5 drives the first conveying assembly to operate, the two pistons 6111 move synchronously, the air flow is limited by the one-way valve 613, so that one of the two three-way pipes 62 can introduce external air into one of the cylinder barrels 611 through the conveying inlet 6111, and the other three-way pipe 62 can introduce the introduced external air from the air inlet 302 into the mixing device 3 through the conveying outlet 6112. In this way, high-speed conveying of external air is realized.

[0071] For the lower second conveying assembly, two three-way pipes 62, one of which has three ends of one input end and two output ends, the input end is communicated with the exhaust port 12, and the two output ends are communicated with the conveying inlets 6111 of the two cylinder barrels 611 respectively, and the remaining one has three ends of one output end and two input ends, the two input ends are communicated with the conveying outlets 6112 of the two cylinder barrels 611 respectively, and the output end is communicated with the separation inlet 21 of the cryogenic oil and gas treatment device 2, so that when the driving mechanism 5 drives the first conveying assembly to operate, the two pistons 6111 move synchronously, the air flow is limited by the one-way valve 613, so that one of the two three-way pipes 62 can introduce the exhaust gas in the storage tank 1 from the exhaust port 12 and then introduce it into one of the cylinder barrels 611 through the conveying inlet 6111, and the other three-way pipe 62 can discharge the introduced exhaust gas from the conveying outlet 6112 and inject it into the cryogenic oil and gas treatment device 2 through the separation inlet 21, so that the VOCs in the exhaust gas are liquefied and separated out in a cylinder cooling mode to form a lean hydrocarbon gas.

[0072] For the filter screen 614 connected to the end of the cylinder barrel 611 in the conveying unit 61, it can prevent external air from entering the inside of the cylinder barrel 611 and affecting the sealing of the piston plate and the cylinder barrel 611.

[0073] Further improvement is that the driving mechanism 5 comprises a driving unit 51, a rotating disc 52 and two transmission units 53 arranged on both sides of the rotating disc 52, the driving unit 51 drives the rotating disc 52 to rotate around the axis of the rotating disc 52, the two transmission units 53 are arranged on both sides of the rotating disc 52 and are respectively connected with the two conveying mechanisms 6, the two transmission units 53 comprise a convex shaft 531 arranged on the rotating disc 52 and spaced from the axis of the rotating disc 52 and a moving frame 532 sleeved on the convex shaft 531, the moving frame 532 is fixedly connected with the piston 612 of the two conveying units 61 of the corresponding conveying mechanism 6, and the moving directions of the two moving frames 532 are consistent with the distribution directions of the two conveying units 61 of the conveying mechanism 6.

[0074] Further specifically, the rotating disc 52 is horizontally arranged, the two conveying mechanisms 6 are arranged on the upper and lower sides of the rotating disc 52 and are connected with the rotating disc 52 through the two transmission units 53, so that when the driving unit 51 drives the rotating disc 52 to rotate, the convex shaft 531 on the rotating disc 52 rotates around the center line of the rotating disc 52 in a fixed direction, the convex shaft 531 acts on the moving frame 532, and then the moving frame 532 reciprocates along the width direction of the mixing device 3, so that the two pistons 612 of the conveying mechanism 6 reciprocate, and then the conveying mechanism 6 can drive the gas flow, introduce the external air into the mixing device 3 and transport the residual tail gas in the storage tank 1 to the cryogenic oil gas treatment device 2.

[0075] Further specifically, as shown in the specific structure of the fixing frame 9 in the utility model, Figures 7-9 The fixing frame 9 comprises a horizontal bottom plate 91, the bottom plate 91 is T-shaped, a motor frame 92 is fixedly arranged above one end of the bottom plate 91, two supports 93 are arranged on the other two ends of the bottom plate 91 and are fixedly arranged above the two supports 93, the two supports 93 are distributed along the vertical direction and have two fixed through holes, the circumferential outer edge of the cylinder barrel 611 is fixedly connected with the circumferential inner wall of the fixed through hole, the adjacent end portions of the two supports 93 are fixedly connected with two cross frames 94 extending along the length direction of the mixing device 3, the end portions of the two cross frames 94 are fixedly connected through a horizontal frame 95, the length direction of the frame 95 is parallel to the width direction of the mixing device 3, the frame 95 comprises two horizontal strips 951 and two vertical strips 952, the two horizontal strips 951 and the two vertical strips 952 are sequentially connected in a head-tail mode to form a rectangular frame, the length direction of the horizontal strip 951 is parallel to the width direction of the mixing device 3, the length direction of the vertical strip 952 is a vertical direction, and the two cross frames 94 are fixedly connected with horizontal bearing frames 96.

[0076] The driving unit 51 comprises a driving motor 511 fixedly arranged above the motor frame 92, and the output end of the driving motor 511 is coaxially connected with a driving gear 512. The outer edge of the rotating disc 52 is arranged with a plurality of convex teeth in an annular array, so that the rotating disc 52 and the convex teeth form a driven gear meshing with the driving gear 512. Two convex shafts 531 are arranged above and below the rotating disc 52 respectively. The rotating disc 52 is arranged with a support bearing 521 below, and the convex shaft 531 below is located inside the support bearing 521. The outer ring of the support bearing 521 is fixedly connected with the bearing frame 96, and the inner ring is fixedly connected with the rotating disc 52 coaxially.

[0077] After the above structure is adopted, the driving motor 511 is started to drive the driving gear 512 to rotate and act on the convex teeth on the outer side of the rotating disc 52. Under the support of the support bearing 521, the rotating disc 52 can rotate around its axis.

[0078] As shown in Figure 7 , Figure 12 and Figure 13 of the two transmission units 53, the length direction of the moving frame 532 is parallel to the length direction of the mixing device 3. The two ends of the moving frame 532 are fixedly connected with a sliding sleeve 534, the sliding sleeve 534 is sleeved on the cross bar 951 and is in sliding fit with the cross bar 951. The two sliding sleeves 534 are fixedly connected through a connecting strip 533 opposite to the rotating disc 52. The connecting strip 533 is fixedly connected with the piston 612. In this way, the moving frame 532 is stably moved along the width direction of the mixing device 3.

[0079] Further improvement is that one of the convex shafts 531 is arranged with an adjusting unit 54 between the convex shaft 531 and the rotating disc 52 to adjust the distance between the axis of the convex shaft 531 and the rotating disc 52. The other convex shaft 531 is fixedly connected with the rotating disc 52. The lean hydrocarbon inlet 301 is connected with a flow sensor 306.

[0080] Specifically, the top surface of the rotating disc 52 is connected with the convex shaft 531 through the adjusting unit 54, the adjusting unit 54 can adjust the distance between the axis of the convex shaft 531 and the axis of the rotating disc 52, so as to adjust the reciprocating moving range of the upper moving frame 532, while the convex shaft 531 located at the bottom is fixed to the bottom surface of the rotating disc 52, so that the reciprocating moving range of the lower moving frame 532 is fixed, and the reciprocating moving frequencies of the two moving frames 532 are the same. Therefore, on the basis of the above, the adjusting unit 54 can be controlled to adjust the distance between the convex shaft 531 and the axis of the rotating disc 52 according to the flow data detected by the flow sensor 306. Specifically, when the flow data detected by the flow sensor 306 is too large, it indicates that there is too much lean hydrocarbon gas and too little external gas in the mixed gas. At this time, the adjusting unit 54 controls the convex shaft 531 to be close to the axis of the rotating disc 52, so as to reduce the moving range of the upper moving frame 532 and reduce the amount of tail gas extracted when the first conveying assembly is running, so as to ensure that there is sufficient air to contact the lean hydrocarbon gas and avoid that the lean hydrocarbon gas is too much to cause insufficient oxidation of carbon monoxide. Conversely, when the flow data detected by the flow sensor 306 is too small, it indicates that there is too little lean hydrocarbon gas and too much external gas in the mixed gas. At this time, the adjusting unit 54 controls the convex shaft 531 to be away from the axis of the rotating disc 52, so as to increase the moving range of the upper moving frame 532 and increase the amount of tail gas extracted when the first conveying assembly is running, so as to ensure that there is sufficient lean hydrocarbon gas to contact the air, and after the mixed gas is formed, it can be introduced into the catalytic oxidation device 4 to realize sufficient oxidation of the lean hydrocarbon gas in the mixed gas, while avoiding too much external air to reduce the catalytic oxidation efficiency of carbon monoxide.

[0081] Further improvement is that the adjusting unit 54 includes an adjusting motor 541 arranged on the convex shaft 531, the adjusting motor 541 is drivingly connected with a lead screw 542, the lead screw 542 is threadedly connected with a sleeve 543, the convex shaft 531 corresponding to the adjusting unit 54 is fixed to the sleeve 543, and the rotating disc 52 is provided with a distance sensor 544 for detecting the position of the sleeve 543.

[0082] Specifically, as shown in Figure 13 and Figure 14 , the top surface of the rotating disc 52 is provided with a long strip-shaped groove, the adjusting unit 54 is arranged on the inner side of the groove, the adjusting unit 54 further includes a support shaft sleeve 545, the adjusting motor 541 and the support shaft sleeve 545 are both fixed in the groove, the sleeve 543 is slidingly fitted in the groove, the lead screw 542 rotates at the inner side of the support shaft sleeve 545 away from the axis of the lead screw 542, the convex shaft 531 is fixed above the sleeve 543, and the distance sensor 544 is fixed to the adjusting motor 541 and faces the sleeve 543.

[0083] After the above structure is adopted, the distance sensor 544 detects the distance position with the screw sleeve 543, so as to determine the distance between the upper convex shaft 531 and the axis of the rotating disc 52, when the distance needs to be adjusted, the motor 541 is adjusted to drive the lead screw 542 to rotate around the axis under the action of the supporting sleeve 545, the lead screw 542 acts on the screw sleeve 543 through the thread, so that the screw sleeve 543 slides along the sliding groove, and then drives the convex shaft 531 to move, the distance adjustment between the axis of the convex shaft 531 and the axis of the rotating disc 52 is realized, so that the reciprocating amplitude of the upper moving frame 532 can be adjusted.

[0084] Further improvement is that the mixing device 3 has a preheating cavity 307 communicated with the air inlet 302 and a heat exchange cavity 308 communicated with the heat exchange outlet 305, the preheating cavity 307 is provided with a preheating coil 31, the output end of the preheating coil 31 is communicated with the heat exchange cavity 308 through a heat insulation pipe 351, the heat exchange cavity 308 is provided with an outer pipe 32, the two ends of the outer pipe 32 are communicated with the heat insulation pipe 351 and the heat exchange outlet 305 respectively, the inner pipe 33 is penetrated in the inner side of the outer pipe 32, the two ends of the inner pipe 33 are communicated with the lean hydrocarbon inlet 301 and the preheating cavity 307 respectively; the outer pipe 32 is densely distributed in the heat exchange cavity 308.

[0085] After the above structure is adopted, the high-temperature waste gas (mainly composed of carbon dioxide generated after carbon monoxide is treated by catalytic oxidation) generated by the catalytic oxidation device 4 enters the preheating coil 31 in the preheating cavity 307 through the heat exchange inlet 304, the high-temperature carbon dioxide flows in the preheating coil 31 at the same time, exchanges heat with the mixed air composed of the lean hydrocarbon gas in the preheating cavity 307 and the external air through the pipe wall of the preheating coil 31, improves the temperature of the mixed air, so that the mixed air can enter the catalytic oxidation device 4 at a higher temperature, so as to promote the contact oxidation of the carbon monoxide gas in the mixed gas and the external air, and improve the carbon monoxide conversion rate.

[0086] After the high-temperature exhaust gas preheats the mixed gas, the high-temperature exhaust gas still has certain heat, and the temperature is significantly higher than the temperature of the external air, especially the temperature of the lean hydrocarbon gas discharged through the exhaust port 22 of the cryogenic oil gas treatment device 2. Based on the above factors, the high-temperature exhaust gas after the first heat exchange is introduced into the heat exchange cavity 308, so that the high-temperature exhaust gas flows in the inner side of the outer pipe 32 at the same time, and the lean hydrocarbon gas after separation has a lower temperature, enters the heat exchange cavity 308 through the lean hydrocarbon gas inlet 301, and flows in the inner pipe 33 inside the outer pipe 32. The high-temperature exhaust gas after the first heat exchange exchanges heat with the low-temperature lean hydrocarbon gas inside the inner pipe 33 through the inner wall of the inner pipe 33, so that the high-temperature exhaust gas is cooled and discharged from the heat exchange outlet 305 of the mixing device 3, and the low-temperature lean hydrocarbon gas after heat exchange is heated to form normal-temperature lean hydrocarbon gas. The inner pipe 33 corresponds to the outer pipe 32 one by one, and the outer pipe 32 is densely distributed in the heat exchange cavity 308, so as to increase the heat exchange contact area. At the same time, by carrying out twice heat exchange on the high-temperature exhaust gas, the heat energy of the high-temperature exhaust gas can be fully utilized to achieve energy saving and environmental protection, so that the temperature of the lean hydrocarbon gas and the external air can be significantly increased, so as to promote the conversion rate of carbon monoxide in the mixed air, reduce the content of carbon monoxide in the final exhaust gas, and reduce the harm to the surrounding environment.

[0087] As shown in Figure 15 and Figure 16 , the lower part of the mixing device 3 is fixed with a horizontal support plate 34, and the bottom surface of the support plate 34 is provided with support feet 341 to support the mixing device 3.

[0088] Further specifically, as shown in Figures 15-21 , the mixing device 3 comprises a heat exchange shell 37, a partition plate 38 and a mixing box 36 connected in sequence, all of which are fixed above the support plate 34. The partition plate 38 is vertically arranged, and the mixing box 36 and the side of the heat exchange shell 37 facing the partition plate 38 are both open. The mixing box 36 and the partition plate 38 form a preheating cavity 307, and the heat exchange shell 37 and the partition plate 38 form a heat exchange cavity 308.

[0089] The mixing box 36 comprises an air inlet cover 363 fixed on the partition plate 38 and a mixing cover 361 fixed on the air inlet cover 363 away from the partition plate 38, and the mixing outlet 303 is arranged on the side of the mixing cover 361 away from the partition plate 38. The mixing cover 361 is fixed with a flow distribution plate 362, and the circumferential inner wall of the flow distribution plate 362 is fixedly connected with the circumferential outer edge of the mixing cover 361. The flow distribution plate 362 is densely provided with flow distribution holes to ensure uniform distribution of the mixed gas flow on the gas inlet side of the mixing outlet 303. The preheating coil 31 is fixed between the mixing box 36 and the air inlet cover 363, and one end of the preheating coil 31 is fixedly and sealingly penetrated through the inner side wall of the mixing cover 361 and is in communication with the outlet of the catalytic outlet 42, so that the high-temperature exhaust gas generated by the catalytic oxidation device 4 can pass through the catalytic outlet 42 and enter the preheating coil 31. The same side of the mixing cover 361 is provided with a heat insulation outlet 3611, and the inner wall of the heat insulation outlet 3611 is fixedly communicated with the other end of the preheating coil 31. The outer wall of the heat insulation outlet 3611 is communicated with the heat exchange cavity 308 through the heat insulation pipe 351.

[0090] The air inlet 302 is arranged at the top of the air inlet cover 363 and is fixedly communicated with an air inlet pipe 3021. The air inlet pipe 3021 is fixedly communicated with the output end of the three-way pipe 62 in the first conveying assembly on the gas outlet side, so that the first conveying assembly can introduce external air into the air inlet cover 363. The side of the air inlet cover 363 opposite to the partition plate 38 is provided with a flow guide hole, and the inner tube 33 is sealingly and fixedly penetrated through the partition plate 38 and passes through the flow guide hole. The circumferential outer edge of the inner tube 33 is spaced from the circumferential inner wall of the flow guide hole, so that the external air entering the inner side of the air inlet cover 363 from the air inlet 302 can enter the inner side of the mixing cover 361 through the above-mentioned gap. The end of the inner tube 33 close to the partition plate 38 is fixed with a flow guide cover 364 facing the end of the inner tube 33, so that when the lean hydrocarbon gas flows out of the inner tube 33, it is guided to contact with the external air passing through the above-mentioned gap through the flow guide cover 364, thereby ensuring sufficient and uniform mixing of the lean hydrocarbon gas and the external air.

[0091] The heat exchange shell 37 comprises an outer shell cover 372, an outer shell cover 371, a closed channel 375 and an exhaust cover 376 connected in sequence, the outer shell cover 372 is fixedly arranged on the outer shell cover 371, the side wall of the outer shell cover 371 is provided with an opening, the opening is fixedly communicated with the end of the heat insulation pipe 351, the heat insulation pipe 351 is covered with a heat insulation cover 35, the heat insulation cover 35 is fixedly communicated with the outer shell cover 371, the closed channel 375, the exhaust cover 376, the partition plate 38, the air inlet cover 363 and the mixing cover 361, in this way, after the high-temperature waste gas after the preheating coil 31 is subjected to primary heat exchange, the high-temperature waste gas can enter the heat exchange cavity 308 through the heat insulation pipe 351, the heat insulation cover 35 can effectively reduce the diffusion of heat, and the waste gas after passing through the heat insulation pipe 351 still has relatively high heat, so that the low-temperature lean hydrocarbon gas can be heated. The outer shell cover 371 is provided with a heat insulation inlet 3711, and the heat insulation inlet 3711 is fixedly communicated with the end of the heat insulation pipe 351 away from the mixing cover 361.

[0092] The inner side of the outer shell cover 371 is fixedly provided with an inner shell cover 373, the opening directions of the two are the same, the opening side of the inner shell cover 373 is fixedly provided with an inner shell cover 374, and the lean hydrocarbon inlet 301 is arranged on the inner shell cover 374 and outwardly extends a lean hydrocarbon inlet pipe which is sealedly penetrated through the outer shell cover 372; the outer pipe 32 and the inner pipe 33 both extend along the length direction parallel to the mixing device 3, one end of the outer pipe 32 is fixedly arranged on the outer shell cover 371 and is communicated with the inner cavity of the outer shell cover 371, the other end is sealedly fixedly penetrated through the exhaust cover 376 and is spaced apart from the partition plate 38, and the outer pipe 32 is located on the inner side of the closed channel 375; one end of the inner pipe 33 is fixedly arranged on the inner shell cover 373 and is fixedly communicated with the inner cavity of the inner shell cover 373, the inner pipe 33 is penetrated through the inner side of the outer pipe 32 and extends into the mixing cover 361; the heat exchange outlet 305 is arranged on the inner side of the exhaust cover 376 and downwardly extends a vertical waste gas pipe 3051. The outer pipe 32 and the inner pipe 33 are both arranged in a rectangular array on the inner side of the closed channel 375.

[0093] After the above structure is adopted, the closed channel 375 can ensure that the outer pipe 32 is in a closed environment and reduce the diffusion of heat to the outside when the high-temperature waste gas passes through the outer pipe 32. When the high-temperature waste gas is used for secondary heat exchange, the high-temperature waste gas enters the inner side of the outer shell cover 371 through the heat insulation pipe 351, passes through the annular gap between the inner wall of the outer pipe 32 and the outer wall of the inner pipe 33, is subjected to heat exchange with the lean hydrocarbon gas in the inner pipe 33 through the side wall of the inner pipe 33, and then enters the exhaust cover 376, is blocked by the partition plate 38 and is discharged through the heat exchange outlet 305; the lean hydrocarbon gas at low temperature enters the inner shell cover 373 through the lean hydrocarbon inlet 301, flows through the inner pipe 33, absorbs the heat of the high-temperature waste gas through the side wall of the inner pipe 33 in the flowing process of the inner pipe 33, so that the temperature of the lean hydrocarbon gas is increased, and the lean hydrocarbon gas flows out from the end of the inner pipe 33 away from the inner shell cover 373 and enters the mixing cover 361 to be contacted with the external air.

[0094] Further improvement is that the bottom of the mixing device 3 is provided with a waste liquid pool 7, and the bottom of the waste gas pipe 3051 is arranged in the waste liquid pool 7.

[0095] Specifically, the top of the waste liquid pool 7 is open and is located directly below the mixing device 3, the bottom of the waste gas pipe 3051 is located directly below the waste liquid pool 7, and the bottom of the waste liquid pool 7 is provided with a waste liquid discharge pipe 71 connected with a waste liquid valve 72.

[0096] Further improvement is that the bottom of the mixing device 3 is provided with a waste liquid pool 7, and the bottom of the waste gas pipe 3051 is arranged in the waste liquid pool 7.

[0097] Further improvement is that the bottom of the mixing device 3 is provided with a waste liquid pool 7, and the bottom of the waste gas pipe 3051 is arranged in the waste liquid pool 7.

[0098] The utility model discloses still provide a kind of tail gas processing method based on negative pressure suction, comprising the following steps:

[0099] S100, discharge: discharge liquid dangerous chemical in storage tank 1;

[0100] S200, air extraction: the tail gas in storage tank 1 is introduced into deep cooling oil gas processing device 2, and discharge lean hydrocarbon gas;

[0101] S300, mixing: external air and lean hydrocarbon gas are introduced into mixing device 3 and mixed, and discharge mixed gas;

[0102] S400, catalytic oxidation: mixed gas is catalytically oxidized, and discharge high-temperature waste gas;

[0103] S500, drainage: waste gas is introduced into mixing device 3 and discharged to outside after heat exchange with external air and lean hydrocarbon gas;

[0104] The conveying mechanism 6 used in step S200 tail gas conveying and the conveying mechanism 6 used in step 300 external air conveying are driven to operate by the same driving mechanism 5.

[0105] Compared with the prior art, the tail gas treatment method has the advantages that the residual tail gas in the storage tank 1 is extracted, the deep cold oil gas treatment device 2 is used for cooling to liquefy VOCs components in the tail gas, and poor hydrocarbon gas is formed; the poor hydrocarbon gas is mixed with external air to form mixed gas, which is introduced into the catalytic oxidation device 4 to perform catalytic oxidation treatment, so that carbon monoxide is catalytically oxidized into carbon dioxide and then discharged; the discharged exhaust gas has a relatively high temperature, so the high-temperature exhaust gas is introduced into the mixing device 3 to heat exchange the poor hydrocarbon gas and the external air, so that the mixed gas has a relatively high temperature before catalytic oxidation, thereby promoting the catalytic oxidation and improving the conversion rate of carbon monoxide; in addition, the conveying mechanism 6 for conveying the tail gas and the external air is driven by the same driving mechanism 5, so that the structure can be simplified, the simultaneous conveying of the external air and the tail gas is ensured, and the compactness of the equipment is ensured, and the occupied space of the equipment is reduced.

[0106] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the art, without departing from the technical principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A negative pressure suction based exhaust gas treatment device, characterized in that, The application relates to a lean hydrocarbon gas mixing device. The device comprises a storage tank, a cryogenic oil gas treatment device, a mixing device, a catalytic oxidation device and a conveying device. The storage tank is provided with a feeding port, a discharging port and a gas extraction port, and the feeding port, the discharging port and the gas extraction port are respectively connected with a feeding valve, a discharging valve and a gas extraction valve. The cryogenic oil gas treatment device is provided with a separation inlet, a gas outlet and a liquid outlet, and the liquid outlet is connected with a liquid outlet valve. The mixing device is provided with a lean hydrocarbon gas inlet, an air inlet, a mixing outlet, a heat exchange inlet and a heat exchange outlet, and the lean hydrocarbon gas inlet is communicated with the gas outlet. The catalytic oxidation device is provided with a catalytic inlet and a catalytic outlet, and the catalytic outlet is communicated with the heat exchange inlet.

2. The negative pressure suction based off-gas treatment device according to claim 1, characterized in that: The conveying device comprises a driving mechanism and two conveying mechanisms, and the driving mechanism is used for providing power to the two conveying mechanisms.

3. The negative pressure suction based exhaust gas treatment device of claim 2, wherein: One of the two conveying mechanisms introduces external air into the air inlet, and the other one inputs the lean hydrocarbon gas output from the gas outlet into the lean hydrocarbon gas inlet to mix the lean hydrocarbon tail gas with the external air.

4. The negative pressure suction based off-gas treatment device according to claim 3, characterized in that: The two conveying mechanisms each comprise two conveying units which are opposite to each other.

5. The negative pressure suction based off-gas treatment device according to claim 4, characterized in that: The two conveying units each comprise a cylinder and a piston which is axially and sealingly connected with the inner wall of the cylinder and is in sliding fit with the cylinder.

6. The negative pressure suction based exhaust gas treatment device of claim 1, wherein: The cylinder is provided with an inlet and an outlet, and the inlet and the outlet are connected with two one-way valves which are opposite in direction.

7. The negative pressure suction based exhaust gas treatment device of claim 6, wherein: The driving mechanism drives the pistons of the two conveying units in the conveying mechanism to move synchronously.

8. The negative pressure suction based off-gas treatment device according to any one of claims 1-7, characterized in that: The driving mechanism comprises a driving unit, a rotating disc and two transmission units which are arranged on the two sides of the rotating disc. The driving unit drives the rotating disc to rotate around the axis of the rotating disc. The two transmission units are respectively connected with the two conveying mechanisms. The two transmission units each comprise a convex shaft which is arranged on the rotating disc and has a spacing with the axis of the rotating disc and a moving frame which is sleeved outside the convex shaft. The moving frame is fixedly connected with the pistons of the two conveying units in the corresponding conveying mechanism. The moving directions of the two moving frames are consistent with the distribution directions of the two conveying units in the conveying mechanism. One of the convex shafts is arranged between the rotating disc to adjust the spacing between the convex shaft and the axis of the rotating disc. The other convex shaft is fixedly connected with the rotating disc. The lean hydrocarbon gas inlet is connected with a flow sensor. The adjusting unit comprises an adjusting motor which is arranged on the convex shaft. The adjusting motor is drivingly connected with a screw rod. The screw rod is threadedly connected with a screw sleeve. The convex shaft corresponding to the adjusting unit is fixed on the screw sleeve. The rotating disc is provided with a distance sensor which is used for detecting the position of the screw sleeve. The mixing device is provided with a preheating cavity which is communicated with the air inlet and a heat exchange cavity which is communicated with the heat exchange outlet. The preheating cavity is provided with a preheating coil pipe. The output end of the preheating coil pipe is communicated with the heat exchange cavity through a heat insulation pipe. The heat exchange cavity is provided with an outer pipe. The two ends of the outer pipe are respectively communicated with the heat insulation pipe and the heat exchange outlet. An inner pipe is penetrated in the inner side of the outer pipe. The two ends of the inner pipe are respectively communicated with the lean hydrocarbon gas inlet and the preheating cavity. The outer pipe is densely arranged in the heat exchange cavity. The heat exchange outlet is arranged at the bottom of the mixing device and is connected with a waste gas pipe which extends downward. The bottom of the waste gas pipe is arranged in a waste liquid pool which is arranged at the bottom of the mixing device.

9. The negative pressure suction based off-gas treatment device according to any one of claims 1-7, characterized in that: A conveying mechanism connected with the air inlet, the input end of which is connected with a filter assembly.

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