Wet sludge energy-saving treatment system

Abstract

The present invention discloses an energy-saving wet sludge treatment system, comprising a vacuum dryer, a biomass gasifier, a steam boiler and a first heat exchanger connected in sequence, the biomass gasifier comprising: a gasifier furnace body, a feed inlet, a biomass gas outlet, a water vapor inlet and an air inlet, the feed inlet being connected to the vacuum dryer; the steam boiler comprising a boiler furnace body, a burner, a biomass gas inlet, a combustion-supporting gas inlet, a water vapor outlet and a high-temperature flue gas outlet, the water vapor outlet being connected to the water vapor inlet of the biomass gasifier; the first heat exchanger comprising: a heat exchanger body, a high-temperature flue gas inlet, a low-temperature flue gas outlet, a cold air inlet and a hot air outlet provided on the heat exchanger body, the high-temperature flue gas inlet being connected to the high-temperature flue gas outlet of the steam boiler, the low-temperature flue gas outlet being connected to the chimney, and the hot air outlet being connected to the air inlet of the biomass gasifier.

Description

Technical Field

[0001] The present invention relates to the field of domestic sludge treatment, in particular to a wet sludge treatment system. Background Art

[0002] The domestic sewage treatment process is accompanied by the discharge of large amounts of sludge. In 2015, sewage treatment plants discharged 35 million tons of sludge, and by 2020, my country's sludge production reached 60 to 90 million tons. This increasing sludge production is in sharp conflict with the severe shortage of sludge treatment capacity and the serious backwardness of treatment methods. Sludge disposal has become an unavoidable urban environmental issue, necessitating an economical and environmentally friendly sludge treatment system for domestic sewage.

[0003] For example, Chinese patent application No. 200410086312.5 discloses a wet sludge incineration treatment method and incineration treatment device, which directly incinerates wet sludge at 800-950°C in an incinerator or incinerates it with auxiliary fuel; the required air is fed into the furnace in stages; and limestone can be added to the furnace to reduce SO2 emissions. The incineration treatment device includes a furnace, a cyclone separator, a return feeder, and a tail flue; the side walls of the furnace are insulated, a wet sludge inlet is provided at the top of the furnace, and an auxiliary fuel inlet is provided at the bottom; and a high-temperature air preheater is provided in the tail flue. However, the wet sludge incineration treatment method and incineration treatment device have the following disadvantages or deficiencies: (1) the harmful gases in the sludge are not effectively removed; (2) the sludge treatment cost is high; and (3) the fly ash content in the flue gas emitted by the incineration treatment device is not monitored, and the fly ash content in the flue gas is an effective means of judging the incineration efficiency and whether carbon neutrality can be achieved, and automatic combustion control cannot be performed.

[0004] Another example is a high-efficiency wet sludge drying and processing equipment disclosed in Chinese patent application No. 201510029611.3, which includes a flat-plate sealed box, a flat conveyor belt installed in the flat-plate sealed box, and the left and right ends of the flat conveyor belt are connected to the conveyor belt traction device through a conveyor belt traction rope. A material distribution and material collection device is provided in the middle of the flat-plate sealed box, and an air intake pipe is provided at the bottom of the flat-plate sealed box, which is connected to the air intake of the air intake fan; the flat-plate sealed box is composed of a transparent plate on the upper surface, a lower membrane plate and a support frame, and an air intake chamber is provided on the transparent plate. However, this high-efficiency wet sludge drying and processing equipment has the following disadvantages or shortcomings: (1) the sludge treatment process is complicated and the cost is high; (2) the heat generated by the sludge combustion is not fully utilized.

[0005] Therefore, it has become an urgent problem to be solved in the industry to provide a wet sludge energy-saving treatment system with low treatment cost, which can fully utilize the recycled sludge, is equipped with an online monitoring system for the fly ash content in the flue gas, and can achieve energy-saving and environmentally friendly treatment. Summary of the Invention

[0006] The purpose of the present invention is to provide an energy-saving wet sludge treatment system, which can fully utilize the recovered sludge to produce biomass gas, and then use the heat energy generated by the combustion of biomass gas to form steam. The steam can not only be used by steam users, but also can be supplied to the biomass gasification furnace for use, thereby achieving the effect of energy-saving and environmentally friendly sludge treatment.

[0007] In order to achieve the above-mentioned purpose, the present invention provides an energy-saving treatment system for wet sludge, comprising a vacuum dryer, a biomass gasifier, a steam boiler and a first heat exchanger connected in sequence, wherein the vacuum dryer is used to dry the wet sludge into sludge particles, the biomass gasifier comprises: a gasifier body, a feed port provided on the top wall of the gasifier body, a biomass gas outlet provided on the side wall of the gasifier body, a water vapor inlet and an air inlet provided on the bottom wall of the gasifier body, and the feed port is connected to the vacuum dryer; the steam boiler comprises a boiler body, a burner provided at one end of the boiler body for supplying biomass gas for combustion, a biomass gas inlet provided on the side wall of the burner The boiler body is provided with a boiler inlet, a combustion-supporting gas inlet, a water vapor outlet on the top wall of the boiler body, and a high-temperature flue gas outlet on the side wall of the boiler body. The biomass gas inlet is connected to the biomass gas outlet of the biomass gasifier, and the water vapor outlet is connected to the water vapor inlet of the biomass gasifier through a water vapor pipeline. The first heat exchanger includes: a heat exchanger body, a high-temperature flue gas inlet, a low-temperature flue gas outlet, a cold air inlet and a hot air outlet provided on the heat exchanger body. The high-temperature flue gas inlet is connected to the high-temperature flue gas outlet of the steam boiler, the low-temperature flue gas outlet is connected to the chimney through a low-temperature flue gas pipeline, and the hot air outlet is connected to the air inlet of the biomass gasifier through a hot air pipeline.

[0008] Preferably, it further includes a carbon neutrality control unit, which includes: a flue gas carbon content (fly ash content in flue gas) detection device installed in the flue gas duct between the high-temperature flue gas outlet of the steam boiler and the high-temperature flue gas inlet of the first heat exchanger, and a first automatic controller that is communicatively connected to the flue gas carbon content (fly ash content in flue gas) detection device through a data line to obtain flue gas carbon content (fly ash content in flue gas) data and automatically adjust the steam boiler combustion conditions according to the flue gas carbon content (fly ash content in flue gas) data to achieve carbon neutrality.

[0009] Optionally, the first heat exchanger is a multi-hole nozzle heat exchanger, comprising: a heat exchanger body and an inner cylinder body with the same width as the heat exchanger body, a cold air intake space is formed between the top wall of the inner cylinder body and the top wall of the heat exchanger body, a hot air outlet space is formed between the bottom wall of the inner cylinder body and the bottom wall of the heat exchanger body, and the inner cylinder body is longitudinally penetrated by a plurality of rectangular multi-hole nozzle groups, each multi-hole nozzle group comprises an outer tube and an inner tube coaxial with the outer tube, and a plurality of inner tubes are provided on the wall of each inner tube. There are dry through holes, the top of the inner tube is open, the bottom of the inner tube is closed, the top of the outer tube is closed, and the bottom of the outer tube is open. The cold air inlet is arranged on the top wall of the heat exchanger body, and the hot air outlet is arranged on the bottom wall of the heat exchanger body. The high-temperature flue gas inlet is arranged on one side wall of the inner cylinder, and the low-temperature flue gas outlet is arranged on the other side wall of the inner cylinder, so that the high-temperature flue gas is filled between the several outer tubes in the inner cavity of the inner cylinder to perform heat exchange with the cold air between the inner tube and the outer tube.

[0010] Preferably, the first heat exchanger is a multi-hole nozzle labyrinth heat exchanger, the high-temperature flue gas inlet is arranged on one side wall of the inner cylinder, the low-temperature flue gas outlet is arranged on the other side wall of the inner cylinder, and the flue gas channel between the high-temperature flue gas inlet and the low-temperature flue gas inlet is arranged in a labyrinth shape in the inner cavity of the inner cylinder.

[0011] Optionally, a hot air box is provided on the hot air pipeline, and the hot air box is provided with an air inlet, a first air outlet and a second air outlet. The air inlet is connected to the hot air outlet of the first heat exchanger, the first air outlet is connected to the air inlet of the biomass gasifier through the first air branch, and the second air outlet is connected to the combustion gas inlet of the burner of the steam boiler through the second air branch.

[0012] Optionally, the low-temperature flue gas pipeline is provided with a first flue gas branch and a second flue gas branch, the first flue gas branch is connected to the first air branch; the second flue gas branch is provided with a mixer, the mixer is provided with a first air inlet, a second air inlet, and an air outlet, the first air inlet is connected to the low-temperature flue gas outlet of the first heat exchanger, the second air inlet is connected to the second air outlet of the hot air box, and the air outlet is connected to the combustion gas inlet of the burner of the steam boiler.

[0013] Preferably, the carbon neutrality control unit further includes a regulating valve provided at the air outlet of the mixer, which is communicatively connected to the first automatic controller via a data line to adjust the amount of reflux flue gas entering the steam boiler through the air outlet of the mixer according to the instructions of the first automatic controller, wherein, when the flue gas carbon content data obtained by the flue gas carbon content detection device exceeds the upper limit threshold set by the first automatic controller, the first automatic controller instructs the regulating valve to increase the amount of flue gas refluxed into the steam boiler until the flue gas carbon content data obtained by the flue gas carbon content detection device is lower than the upper limit threshold set by the first automatic controller; when the flue gas carbon content data obtained by the flue gas carbon content detection device is lower than the lower limit threshold set by the first automatic controller, the first automatic controller instructs the regulating valve to reduce the amount of flue gas refluxed into the steam boiler until the flue gas carbon content data obtained by the flue gas carbon content detection device is higher than the lower limit threshold set by the first automatic controller.

[0014] Optionally, a gas cylinder is provided on the steam pipeline, and the gas cylinder is provided with a steam inlet, a first steam outlet, and a second steam outlet. The steam inlet is connected to the steam outlet of the steam boiler, the first steam outlet is connected to the steam inlet of the biomass gasifier through a first steam branch, and the second steam outlet is connected to the heat user through a second steam branch.

[0015] Optionally, an ejector is provided on the first steam branch, and the ejector is provided with a first ejection inlet, a second ejection inlet, and an ejection outlet. The first ejection inlet is connected to the first steam outlet of the gas cylinder, the second ejection inlet is connected to the vacuum dryer, and the ejection outlet is connected to the water vapor inlet of the biomass gasifier.

[0016] Optionally, the vacuum dryer includes a dryer body and a heating tube arranged in the dryer body, the top wall of the dryer body is provided with a sludge inlet and a drying gas outlet, the bottom wall of the dryer body is provided with a sludge outlet, and the heating tube is provided with a hot water inlet and a cold water outlet; wherein, the sludge inlet is connected to the wet sludge bin, the sludge outlet is connected to the feed port of the biomass gasification furnace, and the drying gas outlet is connected to the second ejector inlet of the ejector.

[0017] Optionally, it also includes a second heat exchanger and an air compressor, the second heat exchanger is provided with a hot lubricating oil inlet, a cold lubricating oil outlet, a hot water outlet and a cold water inlet, the hot water outlet is connected to the hot water inlet of the vacuum dryer, the cold water inlet is connected to the cold water outlet of the vacuum drying device, the hot lubricating oil inlet is connected to the hot lubricating oil outlet of the air compressor, and the cold lubricating oil outlet is connected to the cold lubricating oil inlet of the air compressor.

[0018] Optionally, the sludge inlet is connected to the wet sludge bin via an auger conveyor, and the sludge outlet is connected to the feed port of the biomass gasifier via a conveyor belt.

[0019] Optionally, a silo is provided at the feed inlet of the biomass gasifier, a feed valve is provided at the outlet of the silo, valves are provided at the sludge inlet, drying gas outlet and sludge outlet of the vacuum dryer, and a pressurizing valve is provided at the cold air inlet of the first heat exchanger.

[0020] Preferably, the flue gas carbon content (fly ash content in flue gas) detection device is an infrared camera, which takes at least ten infrared photos (10 to 50 photos, for example, 30 photos) in a unit time (the unit time can be selected from 1, 2, 3, 5, 10, 15, 20, 30, 50, or 60 minutes, for example, 10 minutes), and the first automatic controller synthesizes the at least ten infrared photos into a unit time fusion photo. The first automatic controller obtains the average data value of the flue gas carbon content (fly ash content in flue gas) in a unit time based on the unit time fusion photo, and calculates the average data value of the flue gas carbon content (fly ash content in flue gas) in a unit time based on the flue gas carbon content (fly ash content in flue gas). The average data value of the fly ash content in the steam boiler is used to automatically control the combustion condition of the steam boiler; the first automatic controller includes a wavelet fusion unit, which includes a wavelet decomposition subunit, a feature selection subunit and a wavelet inverse transformation subunit. The wavelet decomposition subunit decomposes at least ten infrared photos to be fused into a series of low-frequency sub-images and high-frequency sub-images in different directions. The feature selection subunit performs feature selection on the low-frequency sub-images and the high-frequency sub-images through feature selection. The wavelet inverse transformation subunit performs wavelet inverse transformation on the fusion result obtained by the feature selection subunit to obtain the required fused image.

[0021] Alternatively, the specific processing process of the wavelet decomposition subunit of the wavelet fusion unit can adopt various methods in the prior art. For example, a first-layer wavelet decomposition is performed on the first infrared photo to be fused to obtain an approximate component L1 and three high-frequency components HV1, HD1, and HH1. Then, a second-layer wavelet decomposition is performed on the second infrared photo to be fused to obtain an approximate component L2 and three high-frequency components HV2, HD2, and HH2, as well as a second-layer approximate component LL2 and three high-frequency components LHV2, LHD2, and LHH2.

[0022] Optionally, the specific processing process of the feature selection subunit can adopt various methods in the existing technology, for example: the approximate component L1 and three high-frequency components HV1, HD1 and HH1 obtained from the first infrared photo to be fused are respectively fused with the second-layer approximate component LL2 and three high-frequency components LHV2, LHD2 and LHH2 obtained from the second infrared photo to be fused.

[0023] For the fusion of low-frequency approximate components L1 and LL2, the specific fusion rules are as follows:

[0024] W L (x,y)=k1W L1 (x,y)+k2W L2(x,y)

[0025] W L (x,y),W L1 (x,y),W L2 (x,y) represents the approximate component subgraphs before and after fusion, respectively, where k1 and k2 are fusion coefficients.

[0026] The specific fusion rules for high-frequency components are as follows:

[0027] W Hi (x,y)=k 1i W Li 1 +k 2i W Li 2 (i=1,2,3)

[0028] W Hi (x,y),W Li 1 、W Li 2 are the high frequency components in the i direction before and after fusion, respectively. 1i 、k 2i are the fusion coefficients respectively.

[0029] The beneficial effects of the present invention are as follows: (1) the potential of sludge is fully exploited, so that it and biomass particles generate biomass gas in the biomass gasifier, which is supplied to the steam boiler for combustion. The generated steam can not only be supplied to heat users, but also be supplied to the biomass gasifier, thereby achieving energy saving; (2) the toxic gas generated when drying wet sludge is injected into the biomass gasifier together with water vapor, thereby avoiding the toxic gas from being discharged into the atmosphere and polluting the environment, thereby achieving environmental protection; (3) the heat of the flue gas discharged by the steam boiler is fully utilized, and the hot air generated after heat exchange with the cold air is supplied to the steam boiler and the biomass gasifier, thereby more thoroughly utilizing the flue gas energy, improving the energy utilization rate, and ensuring the stability of the combustion temperature of the steam boiler and the biomass gasifier; (4) the heat generated by the operation of the air compressor is used to dry the wet sludge, thereby not only improving the drying efficiency of the sludge, but also achieving energy saving; (5) an online monitoring system for the fly ash content in the flue gas is installed, which can automatically adjust the combustion according to the fly ash content in the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The schematic diagram of the structure of the wet sludge energy-saving treatment system of the present invention is shown.

[0031] Figure 2A and Figure 2BA schematic structural diagram showing an embodiment of the first heat exchanger of the present invention is shown.

[0032] Figure 3 A schematic structural diagram showing another embodiment of the first heat exchanger of the present invention is shown.

[0033] Figure 4 A schematic structural diagram of another embodiment of the wet sludge energy-saving treatment system of the present invention is shown. DETAILED DESCRIPTION

[0034] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0035] Please refer to Figure 1 As a non-limiting embodiment, the wet sludge energy-saving treatment system provided by the present invention includes a vacuum dryer 1, a biomass gasifier 2, a steam boiler 3, a first heat exchanger 4, a second heat exchanger 5 and an air compressor 6.

[0036] The wet sludge in the wet sludge bin C enters the vacuum dryer 1 through the auger conveyor J. Figure 1 As shown, the vacuum dryer 1 includes a dryer body (not numbered in the figure) and a heating tube 10. The top wall of the dryer body is provided with a sludge inlet 11 and a drying gas outlet 12, the bottom wall of the dryer body is provided with a sludge outlet 13, and the heating tube 10 is provided with a hot water inlet 101 and a cold water outlet 102. Thus, the wet sludge is transported to the sludge inlet 11 through the auger conveyor J and enters the vacuum dryer 1 for drying. The generated drying gas is discharged from the drying gas outlet 12, and the dried dry sludge is discharged through the sludge outlet 13 and transported to the biomass gasifier 2 through the dry sludge conveyor belt D.

[0037] As another non-limiting embodiment, the heat required by the vacuum dryer 1 is provided by the second heat exchanger 5 and the air compressor 6. Figure 1 As shown, the second heat exchanger 5 is provided with a hot lubricating oil inlet 51, a cold lubricating oil outlet 52, a hot water outlet 53 and a cold water inlet 54. The hot water outlet 53 is connected to the hot water inlet 101 of the vacuum dryer 1, the cold water inlet 54 is connected to the cold water outlet 102 of the vacuum drying device 1, the hot lubricating oil inlet 51 is connected to the hot lubricating oil outlet 61 of the air compressor 6, and the cold lubricating oil outlet 52 is connected to the cold lubricating oil inlet 62 of the air compressor 6.

[0038] In this way, the heat of the hot lubricating oil generated by the working air compressor can be effectively utilized and introduced into the vacuum drying device 1 through the second heat exchanger 5 to heat and dry the wet sludge into dry sludge for subsequent processing.

[0039] The biomass gasifier 2 includes a gasifier body (not numbered in the figure), a feed port 21, a biomass gas outlet 22, a water vapor inlet 23 and an air inlet 24. A silo M is provided at the feed port 21 for storing biomass particles KL and dried sludge after drying in the vacuum dryer 1.

[0040] The steam boiler 3 includes a boiler body 31, a burner 32, a biomass gas inlet 321, a combustion-supporting gas inlet 322, a water vapor outlet 311, and a high-temperature flue gas outlet 312. The biomass gas inlet 321 is connected to the biomass gas outlet 22 of the biomass gasifier 2. Thus, under the action of the exhaust fan FJ, the biomass gas is introduced into the steam boiler 3 for combustion. The water vapor outlet 311 is connected to the water vapor inlet 23 of the biomass gasifier 2 through the water vapor pipeline L1, thereby meeting the steam demand of the biomass gasifier 2.

[0041] The first heat exchanger 4 includes a heat exchanger body 40, a high-temperature flue gas inlet 41, a low-temperature flue gas outlet 42, a cold air inlet 43 and a hot air outlet 44. The high-temperature flue gas inlet 41 is connected to the high-temperature flue gas outlet 312 of the steam boiler 3, and the low-temperature flue gas outlet 42 is connected to the chimney Y through a flue gas pipe. The low-temperature flue gas pipeline L2 is connected to the flue gas pipeline between the chimney Y and the low-temperature flue gas outlet 42 to return 30% to 50% of the total flue gas volume to the system for re-combustion. The hot air outlet 44 is connected to the air inlet 24 of the biomass gasifier 2 through the hot air pipeline L3.

[0042] In this non-limiting embodiment, Figure 2A and Figure 2BAs shown, the first heat exchanger 4 is a multi-hole nozzle heat exchanger, whose inner cylinder 45 is as wide as the heat exchanger body 40, a cold air inlet space K1 is formed between the top wall of the inner cylinder 45 and the top wall of the heat exchanger body 40, and a hot air outlet space K2 is formed between the bottom wall of the inner cylinder 45 and the bottom wall of the heat exchanger body 40. The inner cylinder 40 is longitudinally penetrated by a plurality of groups of rectangular multi-hole nozzle groups 46, each group of multi-hole nozzle groups 46 includes an outer tube 461 and an inner tube 462 coaxial with the outer tube, and a plurality of through holes 463 are provided on the tube wall of each inner tube 462. The top of the inner tube 462 is open and the bottom is closed. The top of the outer tube 461 is The top is in a closed state and the bottom is in an open state. The cold air inlet 43 is provided on the top wall of the heat exchanger body 40, the hot air outlet 44 is provided on the bottom wall of the heat exchanger body 40, the high-temperature flue gas inlet 41 is provided on one side wall of the inner cylinder 45, and the low-temperature flue gas outlet 42 is provided on the other side wall of the inner cylinder 45, so that the high-temperature flue gas is filled between the several outer tubes 461 in the inner cavity of the inner cylinder 45 to perform heat exchange on the cold air between the inner tube 462 and the outer tube 461. In order to improve the heat exchange efficiency, a pressurization valve (not shown in the figure) is provided at the cold air inlet 43 of the first heat exchanger to ensure that the pressurized cold air enters the inner tube 462 for heat exchange.

[0043] As another non-limiting embodiment, Figure 3 As shown, the first heat exchanger 4 is a multi-hole nozzle labyrinth heat exchanger, the high temperature flue gas inlet 41 is arranged on one side wall of the inner cylinder 45, and the low temperature flue gas outlet 42 is arranged on the other side wall of the inner cylinder 45. Figure 3 The plurality of porous nozzles 46 are separated by a plurality of holes (shown by the middle dotted line), so that the flue gas channel YT between the high-temperature flue gas inlet 41 and the low-temperature flue gas inlet 42 is set to a labyrinth shape in the inner cavity of the inner cylinder 45, thereby extending the heat exchange path, extending the heat exchange time between the high-temperature flue gas and the cold air, reducing the heat load of each porous nozzle group 46, and thus extending the service life of the entire heat exchanger.

[0044] like Figure 1 As shown, a hot air box 7 is provided on the hot air pipeline L3, and the hot air box 7 is provided with an air inlet 70, a first air outlet 71 and a second air outlet 72. The air inlet 70 is connected to the hot air outlet 44 of the first heat exchanger 4, the first air outlet 71 is connected to the air inlet 24 of the biomass gasifier 2 through the first air branch G1, and the second air outlet 72 is connected to the combustion gas inlet 322 of the burner 32 of the steam boiler 3 through the second air branch G2.

[0045] In this non-limiting embodiment, the low-temperature flue gas pipeline L2 includes a first flue gas branch L21 and a second flue gas branch L22. The first flue gas branch L21 is connected to the first air branch G1. The second flue gas branch L22 is provided with a mixer 8 having a first air inlet 81, a second air inlet 82, and an air outlet 83. The first air inlet 81 is connected to the low-temperature flue gas outlet 42 of the first heat exchanger 4, the second air inlet 82 is connected to the second air outlet 72 of the hot air box 7, and the air outlet 83 is connected to the combustion gas inlet 322 of the burner 32 of the steam boiler 3. The flue gas volume in the first flue gas branch L21 accounts for 30% to 40% of the total flue gas volume in the low-temperature flue gas pipeline L2, and the flue gas volume in the second flue gas branch L22 accounts for 60% to 70% of the total flue gas volume in the low-temperature flue gas pipeline L2.

[0046] In another non-limiting embodiment, a sub-cylinder F is provided on the steam pipeline L1. Sub-cylinder F has a steam inlet F0, a first steam outlet F1, and a second steam outlet F2. Steam inlet F0 is connected to the steam outlet 311 of the steam boiler 3. The first steam outlet F1 is connected to the steam inlet 23 of the biomass gasifier 2 via a first steam branch W1. The second steam outlet F2 is connected to the heat user U via a second steam branch W2. In this non-limiting embodiment, the steam in the first steam branch W1 accounts for 20% to 30% of the total steam in sub-cylinder F, and the steam in the second steam branch W2 accounts for 70% to 80% of the total steam in sub-cylinder F.

[0047] In this non-limiting embodiment, an ejector S is provided on the first steam branch W, and the ejector S is provided with a first ejection inlet S1, a second ejection inlet S2, and an ejection outlet S3. The first ejection inlet S1 is connected to the first steam outlet F1 of the gas cylinder F, the second ejection inlet S2 is connected to the drying gas outlet 12 of the vacuum dryer 1, and the ejection outlet S3 is connected to the water vapor inlet 23 of the biomass gasifier 2.

[0048] In order to facilitate the operation of the control system, a feed valve V1 is provided at the outlet of the silo M, and valves V2 are respectively provided at the sludge inlet 11, the drying gas outlet 12 and the sludge outlet 13 of the vacuum dryer 1.

[0049] Thus, the wet sludge in the vacuum dryer 1 is dried by hot water at about 70 degrees Celsius, and the dry sludge formed by drying enters the biomass gasifier 2 together with the biomass particles. The generated biomass gas is burned in the steam boiler 3, and most of the water vapor generated is used by the heating user U. The remaining small part enters the biomass gasifier 2 together with the toxic and harmful gases generated when drying the wet sludge to react, effectively eliminating the harm of toxic and harmful gases directly discharged into the atmosphere. At the same time, the high-temperature flue gas generated by the steam boiler passes through the first heat exchanger 4 to exchange heat and produce hot air of about 500 degrees Celsius. The hot air can not only be supplied to the biomass gasifier 2 but also to the steam boiler 3, which can not only effectively improve the combustion rate, but also ensure the combustion stability of the furnace body, and the combustion temperature is not easy to fluctuate. In addition, the flue gas temperature after heat exchange is still about 150 degrees Celsius, and the flue gas can also be returned to the biomass gasifier 2 and the steam boiler 3 for combustion, further utilizing the waste heat of the flue gas.

[0050] As another non-limiting embodiment, Figure 4 As shown, it further includes a carbon neutralization control unit 9, which includes: a flue gas carbon content detection device 91, a first automatic controller 92, and a regulating valve 93. Among them, the flue gas carbon content detection device 91 is installed in the flue gas duct between the high-temperature flue gas outlet 312 of the steam boiler 3 and the high-temperature flue gas inlet 41 of the first heat exchanger 4. The first automatic controller 92 is connected to the flue gas carbon content detection device 91 through a data line to communicate with the flue gas carbon content detection device 91 so as to obtain flue gas carbon content (fly ash content in flue gas) data and automatically adjust the combustion conditions of the steam boiler 3 according to the flue gas carbon content (fly ash content in flue gas) data to achieve the purpose of carbon neutrality. The regulating valve 93 is arranged at the air outlet 83 of the mixer 8. The regulating valve 83 is communicatively connected to the first automatic controller 92 via a data line to adjust the amount of reflux flue gas entering the steam boiler 3 through the air outlet 83 of the mixer 8 according to the instructions of the first automatic controller 92. When the flue gas carbon content data obtained by the flue gas carbon content detection device 91 exceeds the upper limit threshold set by the first automatic controller, the first automatic controller 92 instructs the regulating valve 93 to increase the amount of flue gas refluxed into the steam boiler 3 until the flue gas carbon content data obtained by the flue gas carbon content detection device 91 is lower than the upper limit threshold set by the first automatic controller 92. When the flue gas carbon content data obtained by the flue gas carbon content detection device 91 is lower than the lower limit threshold set by the first automatic controller 92, the first automatic controller 92 instructs the regulating valve 93 to reduce the amount of flue gas refluxed into the steam boiler 3 until the flue gas carbon content data obtained by the flue gas carbon content detection device 91 is higher than the lower limit threshold set by the first automatic controller 92.

[0051] Although the preferred embodiments of the present invention have been described in detail herein, it should be understood that the present invention is not limited to the specific structures described and shown in detail herein, and other variations and modifications may be implemented by those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A wet sludge energy-saving treatment system, comprising: A vacuum dryer is used to dry wet sludge into sludge particles, characterized by: The wet sludge energy-saving treatment system further comprises: a biomass gasifier, a steam boiler and a first heat exchanger connected in sequence, wherein: The biomass gasifier comprises: a gasifier body, a feed port provided on the top wall of the gasifier body, a biomass fuel gas outlet provided on the side wall of the gasifier body, a water vapor inlet and an air inlet provided on the bottom wall of the gasifier body, and the feed port is connected to the vacuum dryer; The steam boiler comprises: a boiler furnace body, a burner provided at one end of the boiler furnace body for burning biomass gas, a biomass gas inlet and a combustion-supporting gas inlet provided on a side wall of the burner, a water vapor outlet provided on a top wall of the boiler furnace body, and a high-temperature flue gas outlet provided on a side wall of the boiler furnace body, the biomass gas inlet being connected to the biomass gas outlet of the biomass gasifier, and the water vapor outlet being connected to the water vapor inlet of the biomass gasifier via a water vapor pipeline; The first heat exchanger includes: a heat exchanger body, a high-temperature flue gas inlet, a low-temperature flue gas outlet, a cold air inlet, and a hot air outlet provided on the heat exchanger body, the high-temperature flue gas inlet is connected to the high-temperature flue gas outlet of the steam boiler, the low-temperature flue gas outlet is connected to the chimney through a low-temperature flue gas pipeline, and the hot air outlet is connected to the air inlet of the biomass gasifier through a hot air pipeline; Further comprising a carbon neutrality control unit, the carbon neutrality control unit comprising: a flue gas carbon content detection device installed in a flue gas duct between the high-temperature flue gas outlet of the steam boiler and the high-temperature flue gas inlet of the first heat exchanger, and a first automatic controller communicatively connected to the flue gas carbon content detection device via a data line, the first automatic controller being configured to obtain flue gas carbon content data and automatically adjust the steam boiler combustion condition according to the flue gas carbon content data to achieve carbon neutrality; The flue gas carbon content detection device is an infrared camera, which is configured to take at least ten infrared photos per unit time. The first automatic controller synthesizes the at least ten infrared photos into a fused photo per unit time. The first automatic controller obtains an average data value of the flue gas carbon content per unit time based on the fused photo per unit time, and automatically controls the combustion condition of the steam boiler based on the average data value of the flue gas carbon content. The first automatic controller includes a wavelet fusion unit, which includes a wavelet decomposition subunit, a feature selection subunit, and a wavelet inverse transformation subunit that are communicatively connected. The wavelet decomposition subunit is used to decompose the at least ten infrared photos to be fused into a series of low-frequency sub-images and high-frequency sub-images in different directions. The feature selection subunit is used to perform feature selection and screening on the low-frequency sub-images and the high-frequency sub-images to obtain a fusion result. The wavelet inverse transformation subunit is used to perform an inverse wavelet transformation on the fusion result obtained by the feature selection subunit to obtain the unit time fused photo. The first heat exchanger is a multi-hole nozzle heat exchanger, comprising: the heat exchanger body and an inner cylinder with the same width as the heat exchanger body, a cold air intake space is formed between the top wall of the inner cylinder and the top wall of the heat exchanger body, a hot air outlet space is formed between the bottom wall of the inner cylinder and the bottom wall of the heat exchanger body, the inner cylinder is longitudinally penetrated by a plurality of groups of multi-hole nozzle groups arranged in a rectangular manner, each group of multi-hole nozzle groups comprises an outer tube and an inner tube coaxial with the outer tube, a plurality of through holes are provided on the tube wall of each inner tube, the inner The top of the tube is in an open state, the bottom of the inner tube is in a closed state, the top of the outer tube is in a closed state, and the bottom of the outer tube is in an open state. The cold air inlet is arranged on the top wall of the heat exchanger body, and the hot air outlet is arranged on the bottom wall of the heat exchanger body. The high-temperature flue gas inlet is arranged on one side wall of the inner cylinder, and the low-temperature flue gas outlet is arranged on the other side wall of the inner cylinder, so that the high-temperature flue gas overflows between the several outer tubes in the inner cavity of the inner cylinder to perform heat exchange with the cold air between the inner tube and the outer tube.

2. The wet sludge energy-saving treatment system according to claim 1, characterized in that: A hot air box is provided on the hot air pipeline, and the hot air box is provided with an air inlet, a first air outlet and a second air outlet. The air inlet is connected to the hot air outlet of the first heat exchanger, the first air outlet is connected to the air inlet of the biomass gasifier through a first air branch, and the second air outlet is connected to the combustion gas inlet of the burner of the steam boiler through a second air branch.

3. The wet sludge energy-saving treatment system according to claim 2, characterized in that: The low-temperature flue gas pipeline is provided with a first flue gas branch and a second flue gas branch, the first flue gas branch is connected to the first air branch; the second flue gas branch is provided with a mixer, the mixer is provided with a first air inlet, a second air inlet, and an air outlet, the first air inlet is connected to the low-temperature flue gas outlet of the first heat exchanger, the second air inlet is connected to the second air outlet of the hot air box, and the air outlet is connected to the combustion gas inlet of the burner of the steam boiler; The carbon neutrality control unit further includes a regulating valve provided at the air outlet of the mixer, and the regulating valve is communicatively connected to the first automatic controller via a data line to adjust the amount of reflux flue gas entering the steam boiler through the air outlet of the mixer according to the instructions of the first automatic controller, wherein, when the flue gas carbon content data obtained by the flue gas carbon content detection device exceeds the upper limit threshold set by the first automatic controller, the first automatic controller instructs the regulating valve to increase the amount of flue gas refluxed into the steam boiler until the flue gas carbon content data obtained by the flue gas carbon content detection device is lower than the upper limit threshold set by the first automatic controller; when the flue gas carbon content data obtained by the flue gas carbon content detection device is lower than the lower limit threshold set by the first automatic controller, the first automatic controller instructs the regulating valve to reduce the amount of flue gas refluxed into the steam boiler until the flue gas carbon content data obtained by the flue gas carbon content detection device is higher than the lower limit threshold set by the first automatic controller.

4. The wet sludge energy-saving treatment system according to claim 1, characterized in that: The water vapor pipeline is provided with a gas cylinder, which is provided with a steam inlet, a first steam outlet, and a second steam outlet. The steam inlet is connected to the water vapor outlet of the steam boiler, the first steam outlet is connected to the water vapor inlet of the biomass gasifier through a first steam branch, and the second steam outlet is connected to the heat user through a second steam branch.

5. The wet sludge energy-saving treatment system according to claim 4, characterized in that: An ejector is provided on the first steam branch, and the ejector is provided with a first ejection inlet, a second ejection inlet, and an ejection outlet. The first ejection inlet is connected to the first steam outlet of the gas cylinder, the second ejection inlet is connected to the vacuum dryer, and the ejection outlet is connected to the water vapor inlet of the biomass gasifier.

6. The wet sludge energy-saving treatment system according to claim 5, characterized in that: The vacuum dryer includes a dryer body and a heating pipe arranged in the dryer body. The top wall of the dryer body is provided with a sludge inlet and a drying gas outlet, the bottom wall of the dryer body is provided with a sludge outlet, and the heating pipe is provided with a hot water inlet and a cold water outlet; wherein, the sludge inlet is connected to the wet sludge bin, the sludge outlet is connected to the feed port of the biomass gasification furnace, and the drying gas outlet is connected to the second injection inlet of the ejector.

7. The wet sludge energy-saving treatment system according to claim 6, characterized in that: It also includes a second heat exchanger and an air compressor. The second heat exchanger is provided with a hot lubricating oil inlet, a cold lubricating oil outlet, a hot water outlet and a cold water inlet. The hot water outlet is connected to the hot water inlet of the vacuum dryer, the cold water inlet is connected to the cold water outlet of the vacuum drying device, the hot lubricating oil inlet is connected to the hot lubricating oil outlet of the air compressor, and the cold lubricating oil outlet is connected to the cold lubricating oil inlet of the air compressor.

8. The wet sludge energy-saving treatment system according to claim 6, characterized in that: The sludge inlet is connected to the wet sludge bin through an auger conveyor, and the sludge outlet is connected to the feed port of the biomass gasifier through a conveyor belt. A silo is provided at the feed port of the biomass gasifier, and a feed valve is provided at the outlet of the silo. Valves are respectively provided at the sludge inlet, drying gas outlet and sludge outlet of the vacuum dryer, and a pressurization valve is provided at the cold air inlet of the first heat exchanger.

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