Closed purification and blowdown system for coke oven gas

Abstract

The utility model provides a coke oven gas closed purification blowdown system which comprises a plurality of filters, a sewage collecting tank arranged below the filters, a coke oven gas input header pipe and a first steam conveying header pipe, the coke oven gas input header pipe is divided into a plurality of first branch pipes, and the first steam conveying header pipe is divided into a plurality of second branch pipes. Each filter is provided with a coke oven gas inlet connected with the first branch pipe and a coke oven gas outlet connected with the coke oven gas output pipeline and used for outputting the filtered coke oven gas, a steam connector pipeline is arranged at the top of each filter, and one end, located outside the filter, of each steam connector pipeline is connected with the second branch pipe; the other end of the steam connector pipeline is closed and extends into the filter, a sewage draining exit is formed in the lower portion of the filter, and the sewage draining exit is connected with a sewage collecting tank through a sewage conveying pipeline. The closed purification and blowdown system for the coke oven gas is suitable for different application scenes of comprehensive utilization of the coke oven gas, the risk of gas leakage is reduced, and the environmental pollution condition is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of coke oven gas comprehensive utilization, concretely relates to a coke oven gas closed purification and pollution discharge system with steam purging regeneration. BACKGROUND

[0002] Coke oven gas (COG), also known as coke oven gas, is an important industrial by-product, with high economic value and wide application prospect. Its main components are hydrogen (55%-60%) and methane (23%-27%), as well as a small amount of carbon monoxide (5%-8%), carbon dioxide (1.5%-3.0%), nitrogen (3%-7%), oxygen (less than 0.8%), etc. Due to the high content of combustible components, it belongs to high-calorific-value coal gas, crude coal gas or raw coal gas. In the field of coke oven gas comprehensive utilization, a filter device is provided before the pressurized delivery of coke oven gas by a compressor to remove tar and naphthalene impurities in the coke oven gas, preventing problems such as blockage and corrosion of subsequent equipment after pressurization. Specifically, due to the stickiness and adhesion of tar and naphthalene impurities, if they are not removed by filtration before pressurization, they will gradually accumulate in the impeller, blade, flow passage and other parts of the compressor, reducing the flow area and the efficiency of the compressor. In severe cases, the compressor channel may be blocked, causing compressor failure and affecting the normal operation of the entire production process. The pressurized coke oven gas needs to be delivered to downstream equipment or storage devices through various pipelines. If it contains tar and naphthalene impurities, these impurities may deposit in the pipe bends, valves, reducers and other parts, gradually forming blockages over time, affecting the normal delivery of the gas, and even causing pipe rupture and other safety accidents.

[0003] In the prior art, a traditional basket filter is used for filtration. When replacing the filter screen, the filter is manually cut off at the front and rear, the blocked filter screen is pulled out from the top of the filter, and a new filter screen is replaced. This method requires frequent opening and closing of the valve, which may cause the valve to close loosely. In addition, the filter screen is replaced multiple times, which affects the sealing of the filter and increases the risk of gas leakage during filter screen replacement. In severe cases, it may even cause personal injury. At the same time, the waste water and waste gas generated during the purging of the removed filter screen are not easy to collect, which may cause environmental pollution and adversely affect the image of the enterprise. UTILITY MODEL CONTENTS

[0004] To solve the problem of filter core replacement in the existing coke oven gas comprehensive utilization field, the utility model provides a coke oven gas closed purification and pollution discharge system, which is suitable for different application scenarios of coke oven gas comprehensive utilization, effectively improves the regeneration efficiency of the filter, reduces the labor intensity, reduces the risk of gas leakage, and improves the environmental pollution.

[0005] The technical scheme adopted by the utility model is as follows:

[0006] A closed coke oven gas purification and pollution discharge system, comprising a plurality of filters arranged in parallel, a sewage collection tank arranged below the filters, a coke oven gas input main pipe for conveying coke oven gas to the filters for filtration, and a first steam conveying main pipe for inputting steam into the filters and blowing off impurities, the coke oven gas input main pipe is divided into a plurality of first branch pipes, the first steam conveying main pipe is divided into a plurality of second branch pipes, each filter is provided with a coke oven gas inlet connected with the first branch pipes, a coke oven gas outlet connected with a coke oven gas output pipe and outputting filtered coke oven gas, and a steam interface pipe penetrating through a filter top cover and extending into the filter, one end of the steam interface pipe located outside the filter is connected with the second branch pipes, the other end of the steam interface pipe extending into the filter is a blind end, and the steam interface pipe is provided with a first blowing hole for filter screen regeneration, a pollution discharge opening is formed in the lower part of the filter, and the pollution discharge opening is connected with the sewage collection tank through a sewage conveying pipe.

[0007] Further, the first branch pipes are provided with first cut-off valves for controlling the coke oven gas into the filters, the coke oven gas output pipe is provided with second cut-off valves for controlling the output of the purified coke oven gas out of the filters, the coke oven gas output pipe is merged into a coke oven gas output main pipe connected with downstream devices after the second cut-off valves, and the first cut-off valves and the second cut-off valves can be manual cut-off valves.

[0008] Further, the second branch pipes are provided with steam valves for adjusting the steam pressure into the filters to a set value, for example, 0.3-0.6 KPa, to ensure that the steam temperature (for example, 150-180 ℃) and pressure are suitable for cleaning requirements.

[0009] Further, the sewage conveying pipe is provided with a sewage sight glass for observing the sewage discharge condition and a pollution discharge valve for controlling the sewage discharge to the sewage collection tank along the sewage conveying direction, the sewage conveying pipe is merged into a sewage conveying main pipe connected with a sewage inlet of the sewage collection tank after the pollution discharge valve.

[0010] Further, the filter is a basket filter, comprising a cylinder, a filter screen (or filter core) fixedly connected with the inner wall of the cylinder, a flange cover covering the top opening of the cylinder, a through hole provided on the flange cover and through which a steam interface pipeline penetrates, a liquid level meter port provided on the cylinder and connected with a first remote differential pressure liquid level meter, a support frame arranged in the cylinder and used for reinforcing the steam interface pipeline, a coke oven gas inlet, a coke oven gas outlet and a blowdown port are all provided on the side wall of the cylinder (preferably, the coke oven gas inlet and the coke oven gas outlet are arranged at substantially the same height on the upper part of the cylinder, and the blowdown port is arranged on the lower part of the cylinder and is lower than the liquid level meter port in height), the filter screen is cylindrical and coaxial with the cylinder, and the top opening is inclined, the bottom of the filter screen is closed, the diameter of the filter screen is smaller than the inner diameter of the cylinder, for example, 10-20mm smaller, an oval connecting ring is arranged along the periphery of the top opening of the filter screen, the outer edge of the connecting ring is fixedly connected with the inner wall of the cylinder, the lowest point of the connecting ring is lower than the coke oven gas inlet, and the highest point of the connecting ring is higher than the coke oven gas outlet, the through hole is provided at the center of the flange cover, the steam interface pipeline penetrates through the through hole and is sealingly connected therewith, the first remote differential pressure liquid level meter is used for monitoring the liquid level in the filter and transmitting data to a control center, when the liquid level in the filter reaches 60-70%, a blowdown valve is opened to discharge impurities. The support frame can be two and oppositely arranged, the support frame is used for fixing the steam interface pipeline to avoid vibration, each support frame can comprise an arc-shaped clamp ring embracing the steam interface pipeline, a connecting rod connected with one end of the clamp ring and abutting (or close to) the inner wall of the cylinder, first supporting ears integrally formed with the clamp ring and arranged on both sides of the clamp ring, and first connecting holes provided on the first supporting ears, the steam interface pipeline extends into the filter through the through hole and passes through the support frame, bolts penetrate through the first connecting holes of the two coaxial supports and are tightened with nuts to fix the steam interface pipeline, the flange cover covers the opening at the top end of the cylinder, the flange cover is sealingly connected with the cylinder flange, and the steam interface pipeline is sealingly connected with the through hole of the flange cover, for example, seamless welding is performed.

[0011] Further, a plurality of first purging holes (or first purging orifices) are formed on the pipe wall of the steam interface pipe inside the filter screen, preferably, the plurality of first purging holes are substantially uniformly distributed on the pipe wall of the steam interface pipe inside the filter screen, for example, the first purging holes are substantially uniformly spaced in the circumferential and longitudinal directions of the steam interface pipe inside the filter screen, or preferably, the closer to the bottom of the filter screen, the denser the distribution of the first purging holes, because impurities are enriched at the bottom of the filter screen, increasing the density of the first purging holes to improve the cleaning effect. The first purging holes are oriented at an inclined angle, for example, an inclined angle of 30-45°, to the surface of the filter screen. The axial and circumferential spacings between adjacent first purging holes can be, for example, 50-100 mm, preferably 60-80 mm, and the diameter of the first purging holes can be, for example, 2-5 mm, and the diameter of the steam interface pipe can be, for example, DN25-DN50. High-temperature steam enters the steam interface pipe through the second branch pipe and is blown out to the surface of the filter screen through the first purging holes, softening the impurities such as tar and naphthalene on the filter screen and causing them to fall off the surface of the filter screen. Preferably, the closer to the bottom of the filter screen, the denser the distribution of the first purging holes, because impurities are enriched at the bottom of the filter screen, increasing the density of the first purging holes to improve the cleaning effect.

[0012] Further, the filter has at least two, one or more of which are used for filtering, and the other one or more of which are used for steam regeneration or standby. An online differential pressure transmitter is arranged before and after each filter. The online differential pressure transmitter is used to monitor the pressure difference between the inlet and outlet of the coke oven gas in real time and convert it into a standard electrical signal output. According to a set pressure difference threshold value (which can be, for example, 2.5-3 KPa), when the measured pressure difference exceeds the threshold value, it indicates that the filter needs to be treated, and the control center issues an alarm to remind the operator to perform steam purging regeneration on the filter in a timely manner to ensure the filtering effect and normal operation of the system.

[0013] Further, the sewage collection tank is a horizontal container, and its volume can be, for example, 2-10 m³, preferably 3-5 m³. The height difference between the sewage collection tank and the discharge port of the filter can be, for example, 1-8 m, preferably 2-7 m. The liquid in the filter flows to the sewage collection tank under the action of its own gravity. The sewage collection tank can simultaneously receive the drainage from multiple filters and the filter screen regeneration wastewater.

[0014] Further, the top of the tank body of the sewage collection tank is provided with an opening for the second steam delivery pipeline to extend into the tank, an exhaust port for adjusting the gas pressure above the liquid level in the tank, and a first on-site pressure gauge for monitoring the gas pressure in the sewage collection tank. The second steam delivery pipeline extends in the vertical direction to a position close to the tank bottom and is then divided into multiple fourth branch pipes. The ports of the fourth branch pipes are closed and laid along the length direction of the sewage collection tank. The multiple fourth branch pipes are arranged in parallel and at intervals. The distance between the fourth branch pipes and the bottom wall of the sewage collection tank can be, for example, 50-100 mm. Multiple second blowholes are formed in each fourth branch pipe. The second blowholes are arranged in a ring array on the fourth branch pipes. The diameter of the second blowholes can be, for example, 1-5 mm, preferably 2-3 mm. The distance between adjacent second blowholes can be, for example, 80-200 mm, preferably 100-150 mm. High-temperature steam (the temperature can be, for example, 150-180℃, and the pressure can be, for example, 0.3-0.6 KPa) delivered from the second steam delivery pipeline to the bottom of the sewage collection tank is used to heat the viscous substances (such as oil or tar) in the sewage to increase their fluidity and facilitate their discharge through the pipeline. The steam blowing only uses water and steam as the medium and does not introduce chemicals, thereby avoiding pollution of the equipment. The steam blown out of the second blowholes directly acts on the target area, reducing the diffusion and loss of steam in the space inside the tank. The exhaust port is connected to the coke oven gas input main pipe through an exhaust pipeline provided with an exhaust valve. The interior of the sewage collection tank is connected to a second remote transmission pressure difference liquid level gauge, which monitors the liquid level in the sewage collection tank in real time and timely discharges the sewage in the sewage collection tank.

[0015] Further, a base for supporting the fourth branch pipes is arranged below the fourth branch pipes. The base includes an inverted T-shaped support, a bottom support fixed above the support, and a fastener detachably connected to the bottom support. The support is connected, for example, by welding, to the bottom wall of the sewage collection tank. The bottom support and the fastener are symmetrically arranged and are both arc-shaped plates provided with second ears on both sides. Second connection holes are formed in the second ears. The fourth branch pipes are placed in the bottom support, and the fastener is fastened on the fourth branch pipes. The second connection holes of the bottom support and the fastener are coaxial. Bolts pass through the second connection holes and are tightened with nuts to provide stable support for the fourth branch pipes.

[0016] Further, a sewage outlet is formed in the bottom of the tank body of the sewage collection tank. The sewage outlet is connected to a sewage output pipeline. The sewage output pipeline is divided into multiple third branch pipes. The third branch pipes are provided with sewage discharge valves and sewage pumps. The multiple third branch pipes converge into a sewage output main pipe connected to a sewage treatment device. The sewage output main pipe is provided with a second on-site pressure gauge for monitoring the outlet pressure of the sewage pump.

[0017] Further, the coke oven gas input main pipe, the first branch pipe, the sewage output pipeline and the sewage output main pipe are all wrapped with electric heating tapes, the coke oven gas input main pipe and the first branch pipe wrapped with the electric heating tapes prevent saturated water in the coke oven gas from being precipitated in the pipeline during long distance transportation or in the case of low ambient temperature, and the electric heating tapes wrapped outside the sewage output pipeline and the sewage output main pipe are used to heat viscous substances in the sewage to maintain their fluidity.

[0018] The coke oven gas closed purification and pollution discharge system has the advantages that:

[0019] The coke oven gas closed purification and pollution discharge system has the advantages that: the multiple parallel filters are provided, one filter is used as a working filter and the other filter is used as a standby filter, or multiple filters are used as working filters and multiple filters are used as standby filters, the treatment capacity of the coke oven gas is increased, and the overall filtration efficiency is improved; the high-temperature steam is introduced into the filter through the steam interface pipeline, the steam is blown to the surface of the filter screen through the first blowing hole, the tar and the naphthalene and other impurities on the filter screen are softened and removed, the filter screen is thoroughly cleaned, the filtration effect is ensured, the filter screen is prevented from being blocked by the impurities, the filter does not need to be manually disassembled and the filter screen does not need to be replaced, the sealing performance of the filter is ensured, the steam is used for blowing, other chemical substances are not introduced, the difficulty of subsequent sewage treatment is reduced, the corrosion of the equipment and the secondary pollution to the environment are avoided; the sewage collecting tank is arranged to collect the drainage from the filter and the filter screen regeneration wastewater, the sewage in the sewage collecting tank is transported to the sewage treatment device, the whole process is carried out in a closed mode, the working environment is improved, and pollution is avoided; the online differential pressure transmitter arranged before and after the filter is used for monitoring the pressure difference between the coke oven gas inlet and the coke oven gas outlet in real time, the blowing steam is opened at regular time intervals, and the tar, the naphthalene and other impurities attached to the filter screen are blown, so that the filter is regenerated; the first remote differential pressure liquid level meter is arranged to monitor the liquid level in the filter in real time, the blowdown valve is opened in time to discharge the liquid, and the filtration effect is prevented from being affected by excessive accumulation of the liquid in the filter. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a whole schematic view of the coke oven gas closed purification and pollution discharge system.

[0021] Figure 2 It is a plan view of the filter.

[0022] Figure 3 It is a three-dimensional schematic view of the filter.

[0023] Figure 4 It is a longitudinal sectional three-dimensional view of the filter.

[0024] Figure 5 Fig. 1 is a schematic view of the filter screen.

[0025] Figure 6 Fig. 2 is a schematic view of the support frame.

[0026] Figure 7 Fig. 3 is a schematic view of the base.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1 - filter, 101 - coke oven gas inlet, 102 - coke oven gas outlet, 103 - blowdown, 104 - cylinder, 105 - filter screen,

[0029] 106 - flange cover, 107 - level gauge port, 108 - support frame, 1081 - clamp, 1082 - connecting rod, 1083 - first supporting lug, 1084 - first connecting hole, 109 - connecting ring,

[0030] 2 - sewage collection tank,

[0031] 301 - coke oven gas input main pipe, 302 - first branch pipe, 303 - first shut-off valve,

[0032] 401 - first steam delivery main pipe, 402 - second branch pipe, 403 - steam valve,

[0033] 501 - coke oven gas output pipe, 502 - second shut-off valve, 503 - coke oven gas output main pipe,

[0034] 6 - steam connection pipe, 601 - first purging hole,

[0035] 701 - sewage delivery pipe, 702 - sewage sight glass, 703 - blowdown valve, 704 - sewage delivery main pipe,

[0036] 8 - first remote differential pressure liquid level gauge, 9 - on-line differential pressure transmitter, 10 - second steam delivery pipe, 1001 - fourth branch pipe, 11 - first local pressure gauge, 12 - exhaust pipe, 13 - exhaust valve, 14 - second remote differential pressure liquid level gauge,

[0037] 15 - base, 1501 - support, 1502 - bottom support, 1503 - fastener, 1504 - second connecting hole,

[0038] 16 - sewage output pipe, 1601 - third branch pipe, 1602 - sewage discharge valve, 1603 - blowdown pump,

[0039] 17 - sewage output main pipe, 18 - second local pressure gauge. DETAILED DESCRIPTION

[0040] The utility model discloses below will refer to the drawing and combine the embodiment to explain in detail.

[0041] As Figures 1-7 The utility model discloses a coke oven gas closed purification pollution discharge system, it includes a plurality of parallelly connected filter 1, set up in the filter 1 below's sewage collection jar 2, be used for the coke oven gas input header pipe 301 of conveying to the filter 1 and be used for the first steam delivery header pipe 401 of input filter 1 and blowing dirt with steam, and the coke oven gas input header pipe 301 is divided into a plurality of first branch pipe 302, and the first steam delivery header pipe 401 is divided into a plurality of second branch pipe 402, every filter 1 is equipped with the coke oven gas import 101 with first branch pipe 302 connection, the coke oven gas export 102 that is connected with the coke oven gas output pipeline 501 and exports the coke oven gas after filtering, and every filter 1 is additionally equipped with the steam interface pipeline 6 that extends into the filter interior through the filter top cap, and one end of steam interface pipeline 6 is connected with second branch pipe 402 outside filter 1, and the other end of steam interface pipeline 6 extending to the filter 1 interior is blind end, and steam interface pipeline 6 is equipped with first blowhole 601 for filter screen regeneration, and the lower part of filter 1 is opened with the sewage outlet 103, and the sewage outlet 103 is connected with sewage collection jar 2 through sewage delivery pipeline 701.

[0042] As Figure 1 Every first branch pipe 302 is equipped with first cut-off valve 303 for controlling the coke oven gas to enter filter 1, and the coke oven gas output pipeline 501 is equipped with second cut-off valve 502 for controlling the coke oven gas after purification to export filter 1, and the coke oven gas output pipeline 501 is converged into coke oven gas output header pipe 503 and is connected with downstream device after second cut-off valve 502, and first cut-off valve 303 and second cut-off valve 502 can be manual cut-off valve for example.

[0043] As Figure 1 Every second branch pipe 402 is equipped with steam valve 403, and steam valve 403 is used for adjusting the steam pressure entering filter 1 to set value, and set value can be 0.3-0.6KPa for example, to ensure that steam temperature (for example can be 150-180 DEG C) and pressure are suitable for cleaning demand.

[0044] As Figure 1 Sewage delivery pipeline 701 is sequentially equipped with sewage sight glass 702 for observing sewage discharge condition and sewage valve 703 for controlling sewage discharge to sewage collection jar 2 along the sewage delivery direction, and sewage delivery pipeline 701 is converged into sewage delivery header pipe 704 after sewage valve 703, and sewage delivery header pipe 704 is connected with the sewage import of sewage collection jar 2.

[0045] As Figure 2 , Figure 3 ,Figure 4 、 Figure 5 、 Figure 6 As shown in FIGS. 1-3, the filter 1 is a basket filter, which comprises a cylinder 104, a filter screen (or filter core) 105 fixedly connected with the inner wall of the cylinder 104, a flange cover 106 covering the top opening of the cylinder 104, a through hole provided on the flange cover 106 and through which the steam interface pipeline 6 penetrates, a liquid level meter port 107 provided on the cylinder 104 and connected with the first remote differential pressure liquid level meter 8, a support frame 108 arranged in the cylinder 104 and used for reinforcing the steam interface pipeline 6, a coke oven gas inlet 101, a coke oven gas outlet 102, and a blowdown port 103, all of which are provided on the side wall of the cylinder 104. The coke oven gas inlet 101 and the coke oven gas outlet 102 are arranged at the upper part of the cylinder 104 and are at the same height. The blowdown port 103 is arranged at the lower part of the cylinder 104 and is lower in height than the liquid level meter port 107. The filter screen 105 is cylindrical and coaxial with the cylinder 104, and the top opening of the filter screen 105 is inclined. The bottom of the filter screen 105 is closed, and the diameter of the filter screen 105 is smaller than the inner diameter of the cylinder 104, for example, 10-20 mm smaller. An oval connecting ring 109 is arranged along the periphery of the top opening of the filter screen 105. The outer edge of the connecting ring 109 is fixedly connected with the inner wall of the cylinder 104, the lowest point of the connecting ring 109 is lower than the coke oven gas inlet 101, and the highest point of the connecting ring 109 is higher than the coke oven gas outlet 102. The through hole can be provided at the center of the flange cover 106, and the steam interface pipeline 6 penetrates through the through hole and is sealingly connected therewith. The first remote differential pressure liquid level meter 8 is used for monitoring the liquid level in the filter 1 and transmitting data to the control center. When the liquid level in the filter 1 reaches, for example, 60-70%, the blowdown valve 703 is opened to discharge impurities. In an embodiment, the support frame 108 can be two and oppositely arranged. The support frame 108 is used for fixing the steam interface pipeline 6 to avoid vibration. Each support frame 108 comprises an arc-shaped clamp 1081 embracing the steam interface pipeline 6, a connecting rod 1082 connected with one end of the clamp 1081 and abutting (or close to) the inner wall of the cylinder 104, first supporting ears 1083 integrally formed with the clamp 1081 and arranged on both sides of the clamp 1081, and first connecting holes 1084 provided on the first supporting ears 1083. The steam interface pipeline 6 extends into the filter 1 through the through hole and passes through the support frame 108. Screws pass through the coaxial first connecting holes 1084 and are fastened with nuts to fix the steam interface pipeline 6. The flange cover 106 covers the opening at the top end of the cylinder 104 and is sealingly connected with the flange of the cylinder 104. The steam interface pipeline 6 is sealingly connected with the through hole of the flange cover 106, for example, by seamless welding. The support frame 108 can also be implemented in other schemes as long as it can relatively fix the steam interface pipeline 6.

[0046] A plurality of first purge holes (or first purge ports) 601 are formed on the pipe wall of the steam interface pipe 6 inside the filter screen (or filter element) 105, preferably, the plurality of first purge holes 601 are substantially uniformly distributed on the pipe wall of the steam interface pipe 6 inside the filter screen 105, for example, the first purge holes 601 are substantially uniformly spaced in the circumferential and longitudinal directions of the steam interface pipe 6 inside the filter screen 105, or preferably, the closer to the bottom of the filter screen 105, the more densely the first purge holes 601 are distributed, because impurities are enriched at the bottom of the filter screen 105, increasing the density of the first purge holes 601 to improve the cleaning effect. The first purge holes 601 are oriented at an inclined angle, for example, an inclined angle of 30-45°, to the filter screen surface, the axial and circumferential spacings between adjacent first purge holes 601 can be, for example, 50-100 mm, preferably 60-80 mm, and the diameter of the first purge holes 601 can be, for example, 2-5 mm, and the diameter of the steam interface pipe 6 can be, for example, DN25-DN50. High-temperature steam enters the steam interface pipe 6 through the second branch pipe 402 and is blown out to the surface of the filter screen 105 through the first purge holes 601, softening the impurities such as tar and naphthalene on the filter screen 105 and causing them to fall off the surface of the filter screen 105.

[0047] The filter 1 is preferably at least two, one or more of which are used for filtering, and the other one or more are used for steam regeneration or standby. An online differential pressure transmitter 9 is arranged before and after each filter 1. The online differential pressure transmitter 9 is used to monitor the pressure difference between the coke oven gas inlet 101 and the coke oven gas outlet 102 in real time and convert it into a standard electrical signal output. According to a set pressure difference threshold value (which can be, for example, 2.5-3 KPa), when the measured pressure difference exceeds the threshold value, it indicates that the filter 1 needs to be treated, and the control center issues an alarm to remind the operator to timely perform steam purge regeneration on the filter 1 to ensure the filtering effect and normal operation of the system.

[0048] The sewage collection tank 2 is a horizontal container, and the volume can be, for example, 2-10 m³, preferably 3-5 m³. The height difference between the sewage collection tank 2 and the blowdown port 103 of the filter 1 can be, for example, 1-8 m, preferably 2-7 m. The liquid in the filter 1 flows to the sewage collection tank 2 under the action of its own gravity. The sewage collection tank 2 can simultaneously receive the drainage from multiple filters 1 and the regeneration wastewater from the filter screen 105.

[0049] The top of the tank body of the sewage collection tank 2 is provided with an opening for the second steam conveying pipe 10 to extend into the inside thereof, an exhaust port for adjusting the gas pressure above the liquid level in the tank body, and a first on-site pressure gauge 11 for monitoring the gas pressure in the sewage collection tank 2. The second steam conveying pipe 10 extends in the vertical direction to a position close to the tank bottom and is then divided into a plurality of fourth branch pipes 1001. The ports of the fourth branch pipes 1001 are closed and are laid along the length direction of the sewage collection tank 2. The plurality of fourth branch pipes 1001 are arranged in parallel and at intervals. The distance between the fourth branch pipes 1001 and the bottom wall of the sewage collection tank 2 can be, for example, 50-100 mm. A plurality of second blowholes are formed in each fourth branch pipe 1001. The second blowholes are arranged in a ring array on the fourth branch pipe 1001. The diameter of the second blowholes can be, for example, 1-5 mm, preferably 2-3 mm. The distance between adjacent second blowholes can be, for example, 80-200 mm, preferably 100-150 mm. High-temperature steam (the temperature can be, for example, 150-180℃, and the pressure can be, for example, 0.3-0.6 KPa) conveyed from the second steam conveying pipe 10 to the bottom of the sewage collection tank 2 is used to heat the viscous substances (such as oil or tar) in the sewage, so as to increase the flowability of the viscous substances and facilitate the discharge of the viscous substances. The steam blowing only uses water and steam as the medium and does not introduce chemical substances, thereby avoiding pollution of the equipment. The steam blown out of the second blowholes directly acts on the target area, reducing the diffusion and loss of the steam in the space in the tank body. The exhaust port is connected to the coke oven gas input main pipe 301 through an exhaust pipe 12. The exhaust pipe 12 is provided with an exhaust valve 13. The inside of the sewage collection tank 2 is communicated with a second remote transmission pressure difference liquid level gauge 14. The second remote transmission pressure difference liquid level gauge 14 monitors the liquid level height in the sewage collection tank 2 in real time and timely discharges the sewage in the sewage collection tank 2.

[0050] A base 15 for supporting the fourth branch pipe 1001 is arranged below the fourth branch pipe 1001. The base 15 includes an inverted T-shaped support 1501, a bottom support 1502 fixed above the support 1501, and a fastener 1503 detachably connected to the bottom support 1502. The support 1501 is, for example, welded to the bottom wall of the sewage collection tank 2. The bottom support 1502 and the fastener 1503 are symmetrically arranged and are both arc-shaped plates provided with second lugs on both sides. Second connection holes 1504 are formed in the second lugs. The fourth branch pipe 1001 is placed in the bottom support 1502, and the fastener 1503 is buckled on the fourth branch pipe 1001. The second connection holes 1504 of the bottom support 1502 and the fastener 1503 are coaxial. Bolts pass through the second connection holes 1504 and are tightened with nuts, thereby providing stable support for the fourth branch pipe 1001.

[0051] The bottom of the sewage collection tank 2 has a sewage outlet, which is connected to the sewage output pipe 16. The sewage output pipe 16 is divided into multiple third branch pipes 1601. Each third branch pipe 1601 is equipped with a sewage discharge valve 1602 and a sewage pump 1603. The multiple third branch pipes 1601 converge into a sewage output main pipe 17, which is connected to the sewage treatment device. A second local pressure gauge 18 is installed on the sewage output main pipe 17 to monitor the outlet pressure of the sewage pump 1603.

[0052] The coke oven gas inlet main pipe 301, the first branch pipe 302, the sewage outlet pipe 16, and the sewage outlet main pipe 17 are all wrapped with electric heating tape. The electric heating tape on the coke oven gas inlet main pipe 301 and the first branch pipe 302 prevents saturated water in the coke oven gas from precipitating in the pipes during long-distance transportation or in low ambient temperature conditions. The electric heating tape wrapped on the sewage outlet pipe 16 and the sewage outlet main pipe 17 is used to heat the viscous substances in the sewage to maintain its fluidity. Example

[0053] like Figure 1 As shown, the coke oven gas closed purification and sewage discharge system of this embodiment is equipped with two parallel filters 1, one for standby and one for use. Before use, all valves are in the closed state. The working process of the coke oven gas closed purification and sewage discharge system is as follows:

[0054] (1) Coke oven gas from the main gas pipe at a pressure of about 6 kPa and a temperature of about 40°C (the main components and volume percentages are H2: 50-60%, CH4: 20-30%, CO: 5-10%, CO2: 2-5%, N2: 2-5%, C n H m:2-4%, O2: <1% etc.) to the first branch pipe 302, open the first cut-off valve 303 and the second cut-off valve 502, the first branch pipe 302 delivers the gas to the filter 1 to filter the tar, naphthalene, solid particles and dust and other impurities, the filtered gas is output through the coke oven gas output pipeline 501, the saturated water in the gas will be precipitated (the coke oven gas is lower in temperature than the pipeline after entering the filter due to heat dissipation, the local temperature drops below the dew point, resulting in water condensation), and is enriched at the bottom of the filter 1, the liquid level in the filter 1 is monitored at any time through the first remote differential pressure liquid level meter 8, when the liquid level exceeds 50-60% of the liquid level range, the site operator opens the blowdown valve 703, the sewage discharge situation is observed through the sewage sight glass, the sewage is discharged into the sewage collection tank 2 through the sewage delivery pipeline 701 and the sewage delivery main pipe 704 relying on gravity flow, the exhaust valve 13 of the exhaust pipeline 12 is opened, so that the sewage collection tank 2 is connected with the coke oven gas input main pipe 301, facilitating the sewage in the filter 1 to flow into the sewage collection tank 2, the operator observes the liquid discharge situation through the sewage sight glass and judges whether the liquid in the filter is discharged (when the liquid level in the filter 1 monitored by the first remote differential pressure liquid level meter 8 is just level with the height of the blowdown port, it is determined that the liquid is discharged), when the liquid in the filter 1 is discharged, the blowdown valve 703 and the exhaust valve 13 are closed.

[0055] (2) Open the valve on the second steam delivery pipeline 10, deliver high-temperature steam to the bottom of the sewage collection tank 2 to heat the sewage, according to the liquid level height monitored by the second remote differential pressure liquid level meter 14, discharge the sewage in the sewage collection tank 2 to the plant-wide sewage treatment device through the blowdown pump 1603.

[0056] (3) After a period of use, the filter screen 105 of the filter 1 is attached with a large amount of tar and naphthalene, affecting gas delivery, which is shown by the online differential pressure transmitter 9. When the pressure difference between the inlet and outlet of the filter 1 exceeds the set threshold, switching is needed. First, open the first cut-off valve 303 and the second cut-off valve 502 before and after the standby filter 1, and then close the first cut-off valve 303 and the second cut-off valve 502 before and after the filter 1 in use. Open the steam valve 403 on the second branch pipe 402 connected with the filter 1 in use. High-temperature steam (temperature: 150-180℃, pressure: 0.3-0.6MPa) enters the filter 1 in use through the steam interface pipe 6, is blown out through the first blowing hole 601, and blows the filter screen 105. The steam is condensed into steam condensate and temporarily stored at the bottom of the filter 1. After about 1hr of steam regeneration, open the blowdown valve 703 at the bottom, and the regenerated waste water in the filter 1 flows to the sewage collection tank 2 under the action of gravity. Observe the blowdown condition through the sewage sight glass. When the sewage changes from mixed to clear, stop steam blowing, close the blowdown valve 703 and the steam valve 403, and complete the regeneration of the filter screen 105. The blown steam is condensed into steam condensate, mainly water and a small amount of soluble substances, which is easy to handle and is sent to the sewage treatment device together with the sewage through the blowdown pump 1603.

[0057] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A closed-loop purification and wastewater discharge system for coke oven gas, characterized in that, It includes multiple filters (1) arranged in parallel, a wastewater collection tank (2) located below the filters (1), a coke oven gas inlet main (301) for conveying coke oven gas to the filters (1) for filtration, and a first steam delivery main (401) for conveying steam into the filters (1) and purging impurities. The coke oven gas inlet main (301) is divided into multiple first branch pipes (302), and the first steam delivery main (401) is divided into multiple second branch pipes (402). Each filter (1) is provided with a coke oven gas inlet (101) connected to the first branch pipe (302) and a coke oven gas outlet pipe (502). 1) Connect to and output the filtered coke oven gas outlet (102). Each filter (1) is provided with a steam interface pipe (6) that passes through the top cover of the filter and extends into the interior of the filter. One end of the steam interface pipe (6) located outside the filter (1) is connected to the second branch pipe (402). The other end of the steam interface pipe (6) extending into the interior of the filter is a blind end. The steam interface pipe (6) is provided with a first purge hole (601) for filter screen regeneration. The bottom of the filter (1) has a sewage outlet (103). The sewage outlet (103) is connected to the sewage collection tank (2) via a sewage conveying pipe (701).

2. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 1, characterized in that, The first branch pipe (302) is equipped with a first shut-off valve (303) for controlling the coke oven gas entering the filter (1), and the coke oven gas output pipe (501) is equipped with a second shut-off valve (502) for controlling the output of the purified coke oven gas to the filter (1). The coke oven gas output pipe (501) merges into the coke oven gas output main pipe (503) after passing through the second shut-off valve (502) and is connected to the downstream device.

3. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 1 or 2, characterized in that, The second branch pipe (402) is equipped with a steam valve (403), which is used to adjust the steam pressure entering the filter (1) to a set value.

4. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 1, characterized in that, The sewage conveying pipeline (701) is equipped with a sewage sight glass (702) for observing sewage discharge and a drain valve (703) for controlling sewage discharge to the sewage collection tank (2) along the sewage conveying direction. The sewage conveying pipeline (701) merges into the sewage conveying main pipeline (704) after passing through the drain valve (703). The sewage conveying main pipeline (704) is connected to the sewage inlet of the sewage collection tank (2).

5. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 1, characterized in that, The filter (1) is a basket filter, including a cylinder (104), a filter screen (105) fixedly connected to the inner wall of the cylinder (104), a flange cover (106) covering the opening at the top of the cylinder (104), a through hole opened on the flange cover (106) for the steam interface pipe (6) to pass through, a level gauge port (107) opened on the cylinder (104) and connected to the first remote differential pressure level gauge (8), and a support frame (108) set inside the cylinder (104) for reinforcing the steam interface pipe (6). The coke oven gas inlet (101), coke oven gas outlet (102), and sewage outlet (103) are all opened on the cylinder (104). On the side wall of 4), the filter screen (105) is cylindrical and coaxial with the cylinder (104), with an inclined top opening. The bottom of the filter screen (105) is closed. The diameter of the filter screen (105) is smaller than the inner diameter of the cylinder (104). An elliptical connecting ring (109) is provided along the periphery of the top opening of the filter screen (105). The outer edge of the connecting ring (109) is fixedly connected to the inner wall of the cylinder (104). The lowest point of the connecting ring (109) is lower than the coke oven gas inlet (101), and the highest point of the connecting ring (109) is higher than the coke oven gas outlet (102). The steam interface pipe (6) passes through the through hole and is sealed to it; and / or There are two support frames (108) arranged opposite to each other. Each support frame (108) includes an arc-shaped clamp (1081) that surrounds the steam interface pipe (6), a connecting rod (1082) with one end connected to the clamp (1081) and the other end abutting against the cylinder (104), a first lug (1083) integrally formed with the clamp (1081) and set on both sides of the clamp (1081), and a first connecting hole (1084) opened on the first lug (1083).

6. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 5, characterized in that, Multiple first purge holes (601) are formed on the wall of the steam interface pipe (6) located inside the filter screen (105). The first purge holes (601) are distributed at approximately uniform intervals in the circumferential and longitudinal directions of the steam interface pipe (6) located inside the filter screen (105), or the first purge holes (601) are more densely distributed closer to the bottom of the filter screen (105); and / or The first purge hole (601) is aligned with the filter screen surface at an angle.

7. The coke oven gas closed purification and sewage discharge system according to claim 1, 5 or 6, characterized in that, There are at least two filters (1), one or more of which are used for filtration and the other one or more are used for steam regeneration or standby. An online differential pressure transmitter (9) is installed before and after each filter (1). The online differential pressure transmitter (9) is used to monitor the pressure difference between the coke oven gas inlet (101) and the coke oven gas outlet (102) in real time.

8. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 1, characterized in that, The top of the sewage collection tank (2) is provided with an opening for the second steam conveying pipe (10) to extend into it, an exhaust port for adjusting the air pressure above the liquid surface in the tank, and a first local pressure gauge (11) for monitoring the air pressure inside the sewage collection tank (2). The second steam conveying pipe (10) extends vertically to a position near the bottom of the tank and then divides into multiple fourth branches (1001). The ports of the fourth branches (1001) are closed and laid along the length of the sewage collection tank (2). Multiple fourth branches (1001) are arranged in parallel and spaced apart. Multiple second purge holes are opened on each fourth branch (1001). The second purge holes are arranged in a ring array on the fourth branch (1001). The exhaust port is connected to the coke oven gas input main pipe (301) through the exhaust pipe (12). An exhaust valve (13) is provided on the exhaust pipe (12). The interior of the sewage collection tank (2) is connected to the second remote differential pressure level gauge (14).

9. The closed-loop purification and wastewater discharge system for coke oven gas according to claim 8, characterized in that, The fourth branch pipe (1001) is provided with a base (15) for supporting the fourth branch pipe (1001). The base (15) includes an inverted T-shaped bracket (1501), a base support (1502) fixed above the bracket (1501), and a fastener (1503) detachably connected to the base support (1502). The base support (1502) and the fastener (1503) are symmetrically arranged, and both are arc-shaped plates with second ears on both sides. The second ears have a second connection hole (1504).

10. The coke oven gas closed purification and sewage discharge system according to claim 1 or 8, characterized in that, The bottom of the sewage collection tank (2) has a sewage outlet, which is connected to the sewage output pipe (16). The sewage output pipe (16) is divided into multiple third branches (1601). Each third branch (1601) is equipped with a sewage discharge valve (1602) and a sewage pump (1603). The multiple third branches (1601) converge into a sewage output main pipe (17) which is connected to the sewage treatment device. A second local pressure gauge (18) is installed on the sewage output main pipe (17) to monitor the outlet pressure of the sewage pump (1603).

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