A thermal desorption tail gas integrated condensation dust removal device and method

Abstract

The application discloses a kind of thermal desorption tail gas integration condensing dust removal device and method.The device includes condensing dust removal tower and the condensing dust removal tower is arranged from bottom to top with first stage condensing spray system, second stage condensing spray system and third stage condensing water removal system;Thermal desorption tail gas is separated out dust and heavy oil in turn through first stage condensing spray system, separated out light oil through second stage condensing spray system, and condensing water removal is carried out through third stage condensing water removal system;First stage condensing spray system includes first stage condensing sprayer and first stage cooling coil;Second stage condensing spray system includes first mist eliminator, second stage condensing liquid collection plate, gas deflection plate and second stage condensing sprayer;Third stage condensing water removal system includes second mist eliminator, third stage condensing liquid collection plate, baffle and third stage condensing coil.The device uses multistage condensing technology to effectively remove dust in thermal desorption tail gas, improve oil product recovery rate in thermal desorption tail gas, realize oil product resource classification recovery, reduce the processing difficulty of condensing liquid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil-containing waste treatment in the petrochemical industry, and particularly relates to a heat desorption tail gas integrated condensation and dust removal device and method. BACKGROUND

[0002] Heat desorption refers to a process of separating organic pollutants in solid waste by direct or indirect heat exchange, and effectively collecting and processing the volatilized pollutants (heat desorption tail gas). For oil-containing solid waste such as oily sludge, heat desorption gas is mainly composed of particulate matter, organic hydrocarbons and water, etc. In order to realize the recycling of oil and gas resources and the harmless treatment of tail gas, the desorption gas needs to be dusted first to avoid dust in the desorption gas from settling in the condensation system and mixing with oil and water to block the pipeline. The dust-removed gas enters the condensation system to separate into condensate and non-condensable gas. The condensate enters the settling tank for oil-water separation, and the non-condensable gas enters the tail gas treatment system for incineration and harmless treatment.

[0003] At present, the commonly used dust removal and condensation method is mainly cyclone dust removal + water spray condensation: the cyclone dust collector is used to pre-remove dust from the dust-containing desorption gas, and then the dust-removed gas enters the water spray tank to further remove fine particles in the desorption gas while achieving cooling and condensation by cold water spray condensation. SUMMARY

[0004] The inventors found that the above-mentioned "cyclone dust removal + water spray condensation" method, although having higher efficiency than indirect tube heat exchange and better condensation effect, is widely used in engineering projects. However, this process has the following problems:

[0005] (1) The condensate is a three-phase mixture of oil, water and mud, and is highly emulsified by high-speed stirring of the circulating pump. The oil recovery is difficult, the quality of the separated crude oil is poor, and it still needs to be treated deeply. Moreover, the treatment difficulty of the oily wastewater after oil recovery is increased.

[0006] (2) The desorption gas temperature is generally above 300℃. In order to fully condense and recover oil, the temperature of all desorption gas needs to be reduced to below 60℃, so a large amount of cooling water is consumed. Even so, a small amount of oil and gas will still condense and coking in the subsequent pipeline, affecting the stability of long-term operation of the device.

[0007] In order to at least partially solve the technical problems existing in the prior art, the inventors make the present application, which provides a heat desorption tail gas integrated condensation and dust removal device and method through specific embodiments. The device can effectively remove solid particles in the heat desorption tail gas by combining direct condensation and indirect condensation, realize classified recovery of oil resources, and reduce the treatment difficulty of the condensate.

[0008] In a first aspect, the embodiments of the present application provide a thermal desorption tail gas integrated condensation and dust removal device, comprising a condensation and dust removal tower and a first-stage condensation spray system, a second-stage condensation spray system and a third-stage condensation and water removal system arranged in the condensation and dust removal tower from bottom to top; the first-stage condensation spray system is used for separating dust and heavy oil from the thermal desorption tail gas, the second-stage condensation spray system is used for separating light oil from the thermal desorption tail gas that has passed through the first-stage condensation spray system, and the third-stage condensation and water removal system is used for condensing and removing water from the thermal desorption tail gas that has passed through the second-stage condensation spray system.

[0009] The first-stage condensation spray system comprises a first-stage condensation sprayer and a first-stage cooling coil, and a thermal desorption tail gas inlet is located between the first-stage condensation sprayer and the first-stage cooling coil.

[0010] The second-stage condensation spray system comprises a first mist eliminator, a second-stage condensation liquid collecting plate, a gas deflection plate and a second-stage condensation sprayer.

[0011] The third-stage condensation and water removal system comprises a second mist eliminator, a third-stage condensation liquid collecting plate, a baffle plate and a third-stage condensation coil.

[0012] In a second aspect, the embodiments of the present application provide a thermal desorption tail gas integrated condensation and dust removal method, comprising condensation and dust removal treatment of the thermal desorption tail gas by using the above-mentioned thermal desorption tail gas integrated condensation and dust removal device.

[0013] The above-mentioned technical solutions provided by the embodiments of the present application have at least the following beneficial effects:

[0014] (1) The thermal desorption tail gas integrated condensation and dust removal device provided by the embodiments of the present application comprises a condensation and dust removal tower and a first-stage condensation spray system, a second-stage condensation spray system and a third-stage condensation and water removal system arranged in the condensation and dust removal tower from bottom to top, and the thermal desorption tail gas sequentially passes through the first-stage condensation spray system to separate dust and heavy oil, passes through the second-stage condensation spray system to separate light oil, and passes through the third-stage condensation and water removal system to condense and remove water. The multi-stage condensation technology is adopted, the thermal desorption tail gas is treated by the method combining the direct spray condensation process and the indirect coil condensation process, the purification efficiency of the thermal desorption tail gas is improved, the oil product resources are classified and recovered, the treatment difficulty of the condensate is reduced, and at the same time, the two-stage spray condensation system is adopted, the solid particles in the thermal desorption tail gas are cleaned in the spray condensation process, the small-particle solid is condensed into large-particle solid, the solid is separated from the gas, the thermal desorption tail gas is treated for dust removal, and the dust removal efficiency of the thermal desorption tail gas is improved.

[0015] (2) The thermal desorption tail gas integrated condensation and dust removal device provided by the embodiment of the present application is provided with a two-stage condensate collecting plate, a gas turning plate, a three-stage condensate collecting plate and a baffle plate and other components inside the condensation and dust removal tower, so as to force the thermal desorption tail gas to turn, so that the thermal desorption tail gas can be fully condensed in each stage of the condensation system, and the purification efficiency of the thermal desorption tail gas is improved; a plurality of mist eliminators are used to purify the gas entering the next stage of condensation, so as to prevent thermal carriers of different properties from being mixed, and the purification efficiency of the thermal desorption tail gas is improved.

[0016] (3) The thermal desorption tail gas integrated condensation and dust removal device provided by the embodiment of the present application is provided with a two-stage condensate collecting plate, a gas turning plate, a three-stage condensate collecting plate and a baffle plate and other components inside the condensation and dust removal tower, so as to force the thermal desorption tail gas to turn, so that the thermal desorption tail gas can be fully condensed in each stage of the condensation system, and the purification efficiency of the thermal desorption tail gas is improved; a plurality of mist eliminators are used to purify the gas entering the next stage of condensation, so as to prevent thermal carriers of different properties from being mixed, and the purification efficiency of the thermal desorption tail gas is improved.

[0017] The technical solutions of the present application will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation on the present application. In the drawings:

[0019] Figure 1 Fig. 1 is a structural schematic diagram of the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application;

[0020] Figure 1 Fig. 1 is a structural schematic diagram of the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 2 is a structural schematic diagram of the condensation and dust removal tower A in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 3 is a structural schematic diagram of the first condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 4 is a structural schematic diagram of the second condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; and Fig. 5 is a structural schematic diagram of the third condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application.

[0020] Figure 1 Fig. 1 is a structural schematic diagram of the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 2 is a structural schematic diagram of the condensation and dust removal tower A in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 3 is a structural schematic diagram of the first condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 4 is a structural schematic diagram of the second condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; and Fig. 5 is a structural schematic diagram of the third condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application.

[0020] Figure 1 Fig. 1 is a structural schematic diagram of the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 2 is a structural schematic diagram of the condensation and dust removal tower A in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 3 is a structural schematic diagram of the first condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; Fig. 4 is a structural schematic diagram of the second condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application; and Fig. 5 is a structural schematic diagram of the third condensation and dust removal system in the thermal desorption tail gas integrated condensation and dust removal device in the embodiment of the present application. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and so that the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0022] In order to solve the problems of low oil recovery efficiency, difficulty in treating oily sewage and large consumption of cooling water in the existing water spray condensation process of thermal desorption tail gas, the embodiment of the present application provides a thermal desorption tail gas integrated condensation and dust removal device and method, which can effectively remove solid particles in the thermal desorption tail gas by combining direct condensation and indirect condensation, improve the oil recovery rate of the thermal desorption tail gas, realize classified recovery of oil resources, reduce the difficulty of treating condensed liquid, and reduce the consumption of cooling water.

[0023] EMBODIMENT

[0024] The embodiment of the present application provides a thermal desorption tail gas integrated condensation and dust removal device, the structure of which is shown in Figure 1 The device comprises a condensation and dust removal tower A and a first-stage condensation spray system 1, a second-stage condensation spray system 2 and a third-stage condensation and water removal system 3 arranged from bottom to top in the condensation and dust removal tower A.

[0025] The first-stage condensation spray system 1 is used for separating dust and heavy oil from the thermal desorption tail gas, the second-stage condensation spray system 2 is used for separating light oil from the thermal desorption tail gas that has passed through the first-stage condensation spray system 1, and the third-stage condensation and water removal system 3 is used for condensing and removing water from the thermal desorption tail gas that has passed through the second-stage condensation spray system 2. That is, the thermal desorption tail gas sequentially passes through the first-stage condensation spray system 1 to separate dust and heavy oil, passes through the second-stage condensation spray system 2 to separate light oil, and passes through the third-stage condensation and water removal system 3 to condense and remove water.

[0026] Further, since the spray cooling of the first-stage condensation spray system cannot separate all dust (solid particles) from the thermal desorption tail gas, the thermal desorption tail gas that enters the second-stage condensation spray system from the first-stage condensation spray system will further separate a small amount of dust under the action of the spray cooling of the second-stage condensation spray system while separating light oil.

[0027] The first-stage condensation spray system 1 comprises a first-stage condensation sprayer 11 and a first-stage cooling coil 12, and a thermal desorption tail gas inlet 13 is located between the first-stage condensation sprayer 11 and the first-stage cooling coil 12.

[0028] The secondary condensation spray system 2 comprises a first mist eliminator 21, a secondary condensate collecting plate 22, a gas deflection plate 23 and a secondary condensation sprayer 24.

[0029] In some embodiments, the gas deflection plate 23 is located on the side of the secondary condensation sprayer 24, and the gas deflection plate 23 is located on the same side as the first mist eliminator 21; the upper end of the gas deflection plate 23 is connected to the tertiary condensate collecting plate 32, and the distance between the lower end of the gas deflection plate 23 and the secondary condensate collecting plate 22 meets the distance requirement.

[0030] The hot desorption tail gas passes through the first mist eliminator 21 to remove liquid, and then enters the secondary condensation spray system 2 through the gap between the lower end of the gas deflection plate 23 and the secondary condensate collecting plate 22.

[0031] The tertiary condensation water removal system 3 comprises a second mist eliminator 31, a tertiary condensate collecting plate 32, a baffle plate 33 and a tertiary condensation coil 34.

[0032] The hot desorption tail gas passes through the second mist eliminator 31 to remove liquid, and then enters the tertiary condensation water removal system 3.

[0033] The hot desorption tail gas integrated condensation dust removal device provided by the embodiment of the application comprises a condensation dust removal tower and a first condensation spray system, a secondary condensation spray system and a tertiary condensation water removal system arranged in the condensation dust removal tower from bottom to top, the hot desorption tail gas sequentially passes through the first condensation spray system to separate out dust and heavy oil, passes through the secondary condensation spray system to separate out light oil, and passes through the tertiary condensation water removal system to remove water.

[0034] The condensation dust removal tower is internally provided with components such as a secondary condensate collecting plate, a gas deflection plate, a tertiary condensate collecting plate and a baffle plate to forcibly deflect the hot desorption tail gas, so that the hot desorption tail gas can be fully condensed in each condensation system, and the purification efficiency of the hot desorption tail gas is improved; a plurality of mist eliminators are used to purify the gas entering the next stage of condensation, prevent hot carriers of different properties from being mixed, and improve the purification efficiency of the hot desorption tail gas.

[0035] In the process of separating dust and heavy oil by the first-stage condensing spray system and separating light oil by the second-stage condensing spray system, the temperature of the remaining tail gas has been reduced under the spray condensing effect; and then the water in the tail gas is removed by the third-stage condensing and water-removing system. The condensing and water-removing is completed under the joint action of the baffle and the third-stage condensing coil, and is not by spray but by indirect condensing of the coil. The circulating cooling water flows in the inside of the cooling coil, avoiding the pollution of the circulating cooling water, reducing the waste water treatment capacity of the device, saving water resources, and reducing the operation cost of the device.

[0036] The first mist catcher 21 and the second-stage condensing liquid collecting plate 22 form a first cavity with the condensing and dust-removing tower A, and the first-stage condensing spray system 1 is located in the first cavity. The first mist catcher 21, the second-stage condensing liquid collecting plate 22, the second mist catcher 31, and the third-stage condensing liquid collecting plate 32 form a second cavity with the condensing and dust-removing tower A, and the gas turning plate 23 and the second-stage condensing sprayer 24 are located in the second cavity.

[0037] The condensing and dust-removing tower is further provided with a third mist catcher 4 and a partition plate 35. The second mist catcher 31, the third-stage condensing liquid collecting plate 32, the third mist catcher 4, and the partition plate 35 form a third cavity with the condensing and dust-removing tower A, and the baffle 33 and the third-stage condensing coil 34 are located in the third cavity. The third mist catcher 4 and the partition plate 35 form a fourth cavity with the condensing and dust-removing tower A at the top.

[0038] That is, the first mist catcher 21 and the second-stage condensing liquid collecting plate 22, the second mist catcher 31 and the third-stage condensing liquid collecting plate 32, and the third mist catcher 4 and the partition plate 35 jointly divide the cavity in the condensing and dust-removing tower A into four cavities. The condensing and dust-removing tower is provided with a gas outlet 5 at the top, so that the final non-condensable gas flows out through the gas outlet 5 at the top.

[0039] The flow path of the hot desorption tail gas entering the condensing and dust-removing tower is: after passing through the first cavity, entering the second cavity through the first mist catcher, then entering the third cavity through the second mist catcher, and then entering the fourth cavity through the third mist catcher. The non-condensable gas in the fourth cavity is finally discharged out of the condensing and dust-removing tower. The arrangement of the mist catchers between every two cavities makes it possible to remove as much moisture as possible from the tail gas.

[0040] In some embodiments, the baffle 33 has at least two, one end of one of the two adjacent baffles 33 is connected to one of the partition plate 35 and the third-stage condensing liquid collecting plate 32, and the other end of the other baffle 33 is connected to the other one of the partition plate 35 and the third-stage condensing liquid collecting plate 32.

[0041] Further, an oil-based organic matter can be used as a first-stage heat carrier for the first-stage condensing sprayer.

[0042] The oil-based organic matter is used as a primary heat carrier, and an oil washing process is adopted to improve the condensation efficiency of oil in the thermal desorption tail gas by using the theory of "similar compatibility".

[0043] After the thermal desorption tail gas enters the first cavity of the condensing and dust removing tower, dust and heavy oil are separated under the spray condensation of the primary condensing spray system. The mixture of solid particles, heavy oil (density 900-1000 kg / m 3 ), primary heat carrier (density 820-845 kg / m 3 ) and the like condensed in the primary condensing spray system falls into the bottom of the tower under the action of gravity and is separated by sedimentation in the lower tower body.

[0044] The condensed solid particles have the largest density and are deposited as slurry at the bottom of the tower. The bottom of the condensing and dust removing tower is provided with a slurry outlet 18 which is in communication with a slurry pump 19 for conveying the slurry deposited at the bottom of the tower to a designated sludge recovery site.

[0045] The primary heat carrier has the second largest density and is deposited above the slurry and below the heavy oil. The condensing and dust removing tower is provided with a first heat carrier outlet 14 below the primary condensing spray. The first heat carrier outlet is in communication with the inlet of the primary condensing spray 11 via a first circulating pump 15, i.e., the first heat carrier is circulated and sprayed. The primary cooling coil 12 is used for cooling the first heat carrier.

[0046] Further, the first heat carrier outlet 14 is below the liquid level, and the thermal desorption tail gas inlet 13 is above the liquid level.

[0047] The condensing and dust removing tower is provided with a first condensing liquid outlet 16, i.e., a heavy oil outlet, below the first heat carrier outlet 14. The first condensing liquid outlet 16 is connected with a primary condensing liquid recovery tank 17 (heavy oil recovery tank).

[0048] The secondary heat carrier can be water. The light oil (and condensed particles) condensed by the secondary condensing spray system is mixed with the secondary heat carrier sprayed by the secondary condensing spray and deposited at the bottom of the second cavity. In some embodiments, an oil-water separation system 25 is further included outside the condensing and dust removing tower. The bottom end outlet 26 of the second cavity is connected with the inlet of the oil-water separation system 25. The bottom outlet 251 of the oil-water separation system 25 is connected with the secondary condensing spray 24. A second circulating pump 27 is connected between the bottom outlet 251 of the oil-water separation system 25 and the secondary condensing spray 24 for circulating use of the secondary heat carrier. A secondary cooling coil 253 is arranged inside the oil-water separation system 25 for cooling and reuse of the secondary heat carrier. The top outlet 252 of the oil-water separation system 25 is connected with a secondary condensing liquid recovery tank 28 (light oil recovery tank).

[0049] The thermal desorption tail gas integrated condensation and dust removal device provided by the embodiment of the present application realizes the separation of the condensate and the heat carrier through the density difference. The primary heat carrier, heavy oil and solid particles are separated at the bottom of the multi-stage condensation and dust removal tower. The primary heat carrier after the separation is transported into the primary condensation sprayer through the first circulating pump for the cyclic spraying. The accumulated heavy oil and large particle solid are transported to the primary condensation liquid recovery tank and stored at a designated location every certain period of time. The secondary heat carrier and light oil are separated in the oil-water separation system. The light oil after the separation is transported to the secondary condensation liquid recovery storage. The secondary heat carrier after the separation is transported into the secondary condensation sprayer through the second circulating pump for the cyclic spraying.

[0050] The alkali water can be used as the secondary heat carrier for the spraying of the secondary condensation sprayer. The secondary condensation sprayer system is mainly used for separating the light oil from the thermal desorption tail gas after the primary condensation sprayer. The alkali water is used as the secondary heat carrier. In addition to the condensation and further dust removal, the alkali water can also purify the malodorous gases such as mercaptan in the thermal desorption tail gas.

[0051] In some embodiments, the water chiller 6 located outside the condensation and dust removal tower is further included. The water chiller 6, the third condensation coil 34, the secondary condensation coil 253 and the primary condensation coil 12 are connected in series. The circulating cooling water cooled by the water chiller 6 is transported to the third condensation coil 34, the secondary condensation coil 253 and the primary condensation coil 12 in sequence by the third circulating pump 7 for the indirect heat exchange with the heat medium of each stage.

[0052] The circulating cooling water provides the cold source to the heat carrier of each stage in the series connection mode, thereby avoiding the adverse effect of the "partial flow" on the condensation effect.

[0053] Further, the bypass pipelines are respectively arranged at the inlet and outlet of the water chiller, the third condensation coil, the secondary condensation coil and the primary condensation coil for adjusting the amount of the cooling water, thereby realizing the stable operation of the condensation system of each stage.

[0054] The first circulating pump connected with the primary condensation sprayer and the second circulating pump connected with the secondary condensation sprayer are respectively controlled by the frequency conversion. The amount of the heat carrier sprayed is adjusted by adjusting the delivery amount of the circulating pump, thereby realizing the stable operation of the spraying system of each stage.

[0055] The amount of the circulating cooling water or the heat carrier is changed by the bypass pipeline and the circulating pump, thereby maintaining the stability of the condensation temperature of the thermal desorption tail gas and the operation is simple.

[0056] The bottom outlet 36 of the third cavity is connected with the third condensation liquid recovery tank 37. The thermal desorption tail gas entering the third condensation coil 34 is indirectly exchanged with the circulating cooling water in the coil under the action of the baffle 33. The condensate (mainly composed of water, the density is 1000 kg / m 3 ) is collected by the third condensation liquid collection plate 32 and then enters the third condensation liquid recovery tank 37.

[0057] In some embodiments, the secondary condensate collection plate 22 and the tertiary condensate collection plate 32 are inclined downward.

[0058] The condensate collection plate is designed in an "inclined" structure, so that the condensate can "flow by itself" into the oil-water separator and the tertiary condensate recovery tank, reducing the use of pump-type conveying equipment and the operating cost of the device.

[0059] In some embodiments, the condensing dust removal tower adopts a flange connection mode. Figure 1 The condensing dust removal tower adopts a flange 8 connection.

[0060] The multi-stage condensing dust removal tower adopts a vertical integrated structure design, reducing the land occupation of the device; the flange connection mode is adopted between different parts of the tower body and the pipes passing through the tower body to connect the different sides inside and outside the tower body, so that each equipment or module of the thermal desorption tail gas integrated condensing dust removal device is convenient to install and maintain.

[0061] The setting of the primary condensing spray system, the secondary condensing spray system and the tertiary condensing water removal system makes it possible to use oil-based organic matter as the heat carrier for the primary condensing spray system, use alkaline water as the heat carrier for the secondary spray system, and use circulating cooling water as the heat carrier for the tertiary condensing coil, so that the heavy oil, light oil, water and other components in the thermal desorption tail gas are condensed in different condensers, realizing "graded" resource recovery and reducing the treatment difficulty of the condensate. Further, the primary condensing spray system uses oil-based organic matter as the heat carrier, reducing the amount of steam generated by the heat carrier due to temperature rise during condensation. The secondary condensing spray system uses alkaline water as the heat carrier, which can purify the malodorous gases such as mercaptans in the thermal desorption tail gas.

[0062] Based on the inventive concept of the present application, the present application further provides a thermal desorption tail gas integrated condensing dust removal method, which comprises condensing and dust removing the thermal desorption tail gas by using the above-mentioned thermal desorption tail gas integrated condensing dust removal device.

[0063] Taking the oil-based drilling cuttings of Daqing Oilfield as the raw material, the thermal desorption tail gas generated after the raw material is treated by thermal desorption has a temperature of 350-450℃, a flow rate of 20-40m 3 / h, and a dust content of 5.0-10.0g / m 3 .

[0064] The thermal desorption tail gas enters the condensing dust removal tower and is in contact with the primary heat carrier (oil-based organic matter) sprayed by the primary condensing spray system for heat exchange, and the temperature of the thermal desorption tail gas is reduced to 300℃. The solid particles, heavy oil (density 900-1000kg / m 3) and the dust content in the thermal desorption tail gas is reduced to 0.45-0.90 g / m 3 .

[0065] The mixture of solid particles, heavy oil (density 900-1000 kg / m 3 ), primary heat carrier (density 820-845 kg / m 3 ) and the like condensed in the primary condensing spray system falls into the bottom of the tower under the action of gravity and is separated by sedimentation in the lower tower body. Most of the solid particles will deposit at the bottom of the tower and be transported to a designated location by a slurry pump after a period of accumulation. The primary heat carrier with a smaller density will gather at the upper part of the mixture and be transported to the primary condensing sprayer by a first circulating pump for circulating condensing spray. The heavy oil is located below the primary heat carrier and is transported to a primary condensing liquid recovery tank for storage after a period of accumulation.

[0066] The thermal desorption tail gas after primary condensation enters the secondary condensing spray system through a first mist eliminator and a gas deflector plate and is in contact with the secondary heat carrier (alkali water) sprayed by the secondary condensing spray system for heat exchange, so that the temperature of the thermal desorption tail gas is reduced to 130°C, the dust content in the thermal desorption tail gas is reduced to 0.04-0.08 g / m 3 , and the light oil component (density 820-845 kg / m 3 ) in the thermal desorption tail gas is separated from the thermal desorption tail gas.

[0067] The light oil (density 820-845 kg / m 3 ) and the secondary heat carrier (density 1200 kg / m 3 ) condensed in the secondary condensing spray system are collected by a secondary condensing liquid collection plate into an oil-water separation system. The light oil separated in the oil-water separation system is transported to a secondary condensing liquid recovery tank for storage after a period of accumulation, and the separated water is transported into the secondary condensing sprayer by a second circulating pump for circulating condensing spray of the thermal desorption tail gas.

[0068] The thermal desorption tail gas after secondary condensation enters a tertiary condensing coil through a second mist eliminator and is in indirect heat exchange with circulating cooling water in the condensing coil, so that the temperature of the thermal desorption tail gas is reduced to 50°C, the water in the thermal desorption tail gas is separated from the thermal desorption tail gas, and the non-condensable gas leaves the device through a gas outlet pipe at the top of the tower through a third mist eliminator.

[0069] The thermal desorption tail gas entering the tertiary condensing coil is in indirect heat exchange with the circulating cooling water in the coil under the action of the baffle, and the condensate (mainly composed of water, density 1000 kg / m 3 ) is collected by a tertiary condensing liquid collection plate and then enters a tertiary condensing liquid recovery tank.

[0070] The circulating cooling water is cooled to 7℃ in the water chiller, and the cooled circulating cooling water is sequentially delivered to the third, second and first condensing coils by the third circulating pump, and exchanges heat with the heat medium, and the circulating cooling water after heat exchange is increased in temperature. The circulating cooling water with increased temperature enters the water chiller, and continues to exchange heat with the heat medium after being cooled in the water chiller.

[0071] After being cooled by the circulating cooling water, the temperature of the first and second heat carriers is maintained at 25-35℃, so that the condensing effect of the device is ensured not to change. In the cooling process, the circulating cooling water is located inside the cooling coil and does not contact the heat carrier, so that the water quality of the circulating cooling water is prevented from changing.

[0072] The above-mentioned integrated condensation and dust removal method for thermal desorption tail gas of the embodiment is provided with a multi-stage condensing system in the condensation and dust removal tower, and different components in the thermal desorption tail gas are condensed in different condensing systems. The first-stage condensation adopts an oil washing process, and oil-based organic matter is used as a heat carrier to exchange heat with the thermal desorption tail gas according to the theory of "similar compatibility", so as to improve the condensing efficiency of oil in the desorption gas. The second-stage condensing spray system uses alkaline water as a heat carrier to exchange heat with the thermal desorption tail gas. The third-stage condensing coil uses circulating cooling water as a heat carrier to exchange heat with the thermal desorption tail gas. Through temperature control of each stage of condensation, it is ensured that only oil gas is condensed and separated in the first and second-stage condensing systems, and the third-stage condensing water removal system mainly condenses water vapor, so that the "classification" recovery of heavy oil, light oil and water is realized, and the difficulty of treatment of the condensed liquid is also reduced.

[0073] The current process is to cool all the thermal desorption tail gas to below the target temperature (60℃) at one time. The process route of the present application is to absorb and condense the oil gas in the thermal desorption tail gas at 100℃ or above by using condensed oil, and then to reduce the remaining water vapor to below 60℃, so as to reduce the heat exchange amount required for reducing the oil gas from 100℃ to 60℃, thereby saving the consumption of cooling water.

[0074] It should be understood that the specific order or hierarchy of steps in the disclosed processes should not be taken to imply a certain order of execution. Based on design preference, it should be understood that the specific order or hierarchy of steps in the processes can be rearranged without departing from the scope of protection of the present disclosure. The appended method claims list the elements of the various steps in the exemplary order, and are not intended to be limited to the specific order or hierarchy described.

[0075] In the detailed description above, various features are grouped together in single embodiments for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting a necessity to disclose all features in each and every embodiment. Rather, the application is widely applicable to all combinations of features and embodiments as long as such combinations are not expressly disclosed in the above description. Thus, the following claims are hereby expressly incorporated into this detailed description, with each claim acting as a separate embodiment of the application.

[0076] The foregoing description includes example embodiments of the application. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that many more combinations and permutations of the described embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Additionally, the term "comprising" as used in the specification and in the following claims is to be construed in the broadest sense as meaning "including". Furthermore, any term "or" as used in the specification and claims is to be interpreted as "inclusive or" rather than "exclusive or".

Claims

1. A thermal desorption tail gas integrated condensation and dust removal device, characterized in that, The device comprises a condensation dust removal tower and a first-stage condensation spray system, a second-stage condensation spray system and a third-stage condensation water removal system arranged from bottom to top in the condensation dust removal tower; the first-stage condensation spray system is used for separating dust and heavy oil from the hot desorption tail gas, the second-stage condensation spray system is used for separating light oil from the hot desorption tail gas that has passed through the first-stage condensation spray system, and the third-stage condensation water removal system is used for condensing and removing water from the hot desorption tail gas that has passed through the second-stage condensation spray system. The first-stage condensation spray system comprises a first-stage condensation sprayer and a first-stage cooling coil, and a hot desorption tail gas inlet is arranged between the first-stage condensation sprayer and the first-stage cooling coil. The second-stage condensation spray system comprises a first mist eliminator, a second-stage condensation liquid collecting plate, a gas deflection plate and a second-stage condensation sprayer. The third-stage condensation water removal system comprises a second mist eliminator, a third-stage condensation liquid collecting plate, a baffle plate and a third-stage condensation coil. The first-stage condensation spray system uses oil-based organic matter as a heat carrier, and the second-stage condensation spray system uses alkaline water as a heat carrier. The condensation dust removal tower is provided with a first heat carrier outlet below the first-stage condensation sprayer and a first condensation liquid outlet below the first heat carrier outlet. The first mist eliminator, the second-stage condensation liquid collecting plate, the second mist eliminator, the third-stage condensation liquid collecting plate and the condensation dust removal tower form a second cavity, and the gas deflection plate and the second-stage condensation sprayer are located in the second cavity. The device further comprises an oil-water separation system located outside the condensation dust removal tower, a bottom outlet of the second cavity is connected to an inlet of the oil-water separation system, the oil-water separation system is internally provided with a second-stage cooling coil, a bottom outlet of the oil-water separation system is connected to the second-stage condensation sprayer, and a top outlet of the oil-water separation system is connected to a second-stage condensation liquid recovery tank. The device further comprises a water chiller located outside the condensation dust removal tower, and the water chiller, the third-stage condensation coil, the second-stage cooling coil and the first-stage cooling coil are connected in series.

2. The apparatus of claim 1, wherein, The first mist eliminator and the second-stage condensation liquid collecting plate form a first cavity with the condensation dust removal tower, and the first-stage condensation spray system is located in the first cavity.

3. The apparatus of claim 2, wherein, A second circulating pump is connected between the bottom outlet of the oil-water separation system and the second-stage condensation sprayer.

4. The apparatus of claim 1, wherein, The inlet and outlet of the water chiller, the third-stage condensation coil, the second-stage cooling coil and the first-stage cooling coil are respectively provided with bypass pipelines for adjusting the amount of cooling water. The inlet of the first-stage condensation sprayer and the second-stage condensation sprayer is respectively provided with a bypass pipeline for adjusting the amount of heat carrier spray.

5. The apparatus of claim 2, wherein, The gas deflection plate is located on the side of the second-stage condensation sprayer, and the gas deflection plate and the first mist eliminator are located on the same side. The upper end of the gas deflection plate is connected to the third-stage condensation liquid collecting plate.

6. The apparatus of claim 2, wherein, The top of the condensation dust removal tower is further provided with a third mist eliminator and a partition plate. The second mist eliminator, the third-stage condensation liquid collecting plate, the third mist eliminator and the partition plate form a third cavity with the condensation dust removal tower, and the baffle plate and the third-stage condensation coil are located in the third cavity.

7. The apparatus of claim 6, wherein, The baffle plates are at least two, one end of one of the two adjacent baffle plates is connected with one of the partition plate and the third condensate collecting plate, and the other end of the other baffle plate is connected with the other of the partition plate and the third condensate collecting plate.

8. The apparatus of claim 6, wherein, The bottom end outlet of the third cavity is connected with a third condensate recovery tank.

9. The apparatus of claim 1, wherein, The bottom of the condensing dust removal tower is provided with a slurry outlet which is communicated with a slurry pump. The first heat carrier outlet is communicated with the inlet of the first condensing sprayer via a first circulating pump. The first condensate outlet is connected with a first condensate recovery tank.

10. The device of any one of claims 1 to 9, wherein, The second condensate collecting plate and the third condensate collecting plate are downwardly inclined.

11. The device of any one of claims 1 to 9, wherein, The top of the condensing dust removal tower is provided with a gas outlet.

12. The device of any one of claims 1 to 9, wherein, The condensing dust removal tower is connected by flanges.

13. A method for integrated condensation and dust removal of thermal desorption tail gas, characterized in that, The application further provides a method for condensing and dust removing the thermal desorption tail gas by using the integrated condensing dust removal device. The baffle plates are at least two, one end of one of the two adjacent baffle plates is connected with one of the partition plate and the third condensate collecting plate, and the other end of the other baffle plate is connected with the other of the partition plate and the third condensate collecting plate. The bottom end outlet of the third cavity is connected with a third condensate recovery tank. The bottom of the condensing dust removal tower is provided with a slurry outlet which is communicated with a slurry pump. The first heat carrier outlet is communicated with the inlet of the first condensing sprayer via a first circulating pump. The first condensate outlet is connected with a first condensate recovery tank. The second condensate collecting plate and the third condensate collecting plate are downwardly inclined. The top of the condensing dust removal tower is provided with a gas outlet. The condensing dust removal tower is connected by flanges. The application further provides a method for condensing and dust removing the thermal desorption tail gas by using the integrated condensing dust removal device.

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