A concentrated photothermal sludge pyrolysis and drying treatment system and method

Abstract

The invention discloses a concentrated photothermal sludge pyrolysis and drying treatment system and method, the treatment system comprises a sludge bin, the sludge bin stores wet sludge, the sludge bin outlet has a sludge pump; a heat collecting pipe, the heat collecting pipe is connected with the sludge pump, and the wet sludge is pumped into the heat collecting pipe by the sludge pump; a solar collector, the heat collecting pipe is arranged on the upper part of the solar collector, and the heat collecting pipe absorbs the sunlight reflected by the solar collector to pyrolyze the wet sludge in the pipe; a hot sludge tank, the hot sludge tank is connected with the heat collecting pipe and stores the wet sludge after pyrolysis; a cooling heat exchanger, the cooling heat exchanger is connected with the hot sludge tank to cool the wet sludge; and a sludge dehydrator, the sludge dehydrator is connected with the cooling heat exchanger to mechanically dehydrate the sludge after pyrolysis. The device can control the pyrolysis process by adjusting the sludge pump flow and the system working pressure, realize sludge pyrolysis and drying with extremely low operating cost, and the moisture content of the sludge can be reduced to 30-40%.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal sludge treatment and disposal, and in particular to a concentrated photothermal sludge pyrolysis and drying treatment system and method. Background Art

[0002] Urban sewage treatment produces a large amount of municipal sludge, which is rich in various microorganisms and has a high water content (about 80%), which brings great difficulties to subsequent treatment and disposal.

[0003] Before the sludge is finally disposed of by landfill, incineration, land use, etc., it is necessary to dry the sludge to reduce its moisture content from 80% to 30%-40% or even lower, so as to make it safe and reduce its volume.

[0004] Since the sludge adheres to the heat exchange contact surface, the heat transfer coefficient of the dryer is reduced, the drying efficiency is reduced, and higher energy consumption is required to cross the sticky zone. As a green energy, solar energy can be used as an energy option for sludge pyrolysis and drying, but there is no complete set of sludge pyrolysis and drying treatment system that can be continuously produced at the existing technical level. Summary of the invention

[0005] In view of the high operating cost problem commonly existing in existing sludge drying technologies, the purpose of the present invention is to provide a concentrated solar thermal sludge pyrolysis and drying treatment system, which utilizes solar heat to pyrolyze sludge and combines cooling and dehydration to achieve the sludge drying goal. It has the outstanding advantage of low operating cost, and the moisture content of the sludge can be reduced to 30-40%.

[0006] The present invention also provides a concentrated solar thermal sludge pyrolysis and drying treatment method, which can timely adjust the system working state according to the sludge inflow situation, utilize the heat of sunlight to pyrolyze the sludge, and reduce operating costs.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A concentrated solar thermal sludge pyrolysis and drying treatment system, comprising:

[0009] A sludge bin, in which wet sludge is stored; a sludge pump is provided at the outlet of the sludge bin;

[0010] A heat collecting pipe, wherein the heat collecting pipe is connected to a sludge pump, and the wet sludge is pumped into the heat collecting pipe by the sludge pump;

[0011] A solar thermal collector, wherein the heat collecting tube is arranged on the upper part of the solar thermal collector, and the heat collecting tube absorbs the solar rays reflected by the solar thermal collector to pyrolyze the wet sludge in the tube;

[0012] A hot sludge tank, which is connected to the heat collecting pipe and stores the wet sludge after pyrolysis;

[0013] A cooling heat exchanger, the cooling heat exchanger is connected to the hot sludge tank to cool the wet sludge;

[0014] and a sludge dewatering machine, wherein the sludge dewatering machine is connected to the cooling heat exchanger to perform mechanical dewatering of the wet sludge.

[0015] The solar collector comprises a driving mechanism, a collector main body supporting structure and a reflector, wherein the driving mechanism and the reflector are mounted on the collector main body supporting structure, and the reflector tracks and focuses solar rays onto the surface of the collector tube under the drive of the driving mechanism.

[0016] The solar thermal collector is a line focusing collector; the solar thermal collector and the heat collecting tube are arranged on an empty site or on the top of a building.

[0017] The hot sludge tank is a pressure vessel on which a pressure regulating valve is installed.

[0018] The sludge pump is a positive displacement pump.

[0019] The cooling heat exchanger is a closed surface heat exchanger.

[0020] The sludge dewatering machine is a plate-and-frame dewatering machine or a centrifugal dewatering machine.

[0021] A concentrated photothermal sludge pyrolysis and drying treatment method comprises the following steps:

[0022] The sludge pump pressurizes the wet sludge and pumps it into the heat collecting tube. As the wet sludge flows in the heat collecting tube, it continuously absorbs the solar heat gathered by the solar collector, reaching the temperature and pressure required for sludge pyrolysis, and then gradually undergoes pyrolysis before entering the hot sludge tank.

[0023] The microbial cells in the pyrolyzed sludge are broken and enter the cooling heat exchanger from the hot sludge tank for cooling;

[0024] The wet sludge after pyrolysis and cooling finally enters the sludge dewatering machine for solid-liquid separation.

[0025] When the system pressure needs to be adjusted, select the appropriate working pressure through the pressure control valve on the sludge tank;

[0026] When the drying effect needs to be adjusted, the residence time of the sludge flowing through the system is changed by adjusting the flow rate of the sludge pump.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] The concentrated solar thermal sludge pyrolysis and drying treatment system uses free solar energy to achieve sludge pyrolysis and drying, and has extremely low operating costs. The sludge pyrolysis and drying treatment system uses reflectors and heat collecting tubes to replace large equipment such as boilers and reactors in conventional pyrolysis processes, and the investment is relatively low. The thermal sludge pyrolysis and drying treatment system and method provide new ideas and solutions for low-consumption sludge drying, and have high promotion and application value. The dehydrated sludge and high-concentration organic sewage obtained by low-energy separation using this patented technology can be further tapped for potential utilization. The application of this device enriches the engineering implementation scheme for municipal sludge pyrolysis and drying treatment, greatly reduces the operating cost of sludge pyrolysis and drying, and provides new methods and new options for municipal sludge treatment and disposal. In particular, this system can reduce the moisture content of the sludge to 30-40%.

[0029] This treatment method can control the pyrolysis process by adjusting the sludge pump flow and system working pressure, and realize sludge pyrolysis and drying with a simple system and extremely low operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of a concentrated photothermal sludge pyrolysis and drying treatment system;

[0031] In the figure: 1 is a sludge bin; 2 is a sludge pump; 3 is a heat collecting pipe; 4 is a solar collector; 5 is a hot sludge tank; 6 is a cooling heat exchanger; and 7 is a sludge dewatering machine. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] like Figure 1 As shown, a concentrated solar thermal sludge pyrolysis and drying treatment system includes a sludge bin 1, a sludge pump 2, a heat collecting pipe 3, a solar collector 4, a hot sludge tank 5, a cooling heat exchanger 6, a sludge dewatering machine 7 and necessary connecting pipes and valves.

[0035] Specifically, the sludge bin 1, the sludge pump 2, the heat collecting pipe 3, the hot sludge tank 5, the cooling heat exchanger 6 and the sludge dewatering machine 7 are sequentially connected through connecting pipes, and necessary control valves are arranged on the connecting pipes. The heat collecting pipe 3 is arranged on the upper part of the solar collector 4, and the heat collecting pipe absorbs the solar rays reflected by the solar collector 4 to heat the sludge in the pipe.

[0036] The principle of the present invention is as follows: the sludge generated by the sewage treatment process is stored in the sludge bin; when the sunlight conditions are good during the day, the sludge pump is pressurized at a certain flow rate through the heat collecting pipe and enters the hot sludge tank; during the flow of the sludge in the heat collecting pipe, the sludge continuously absorbs the solar energy gathered by the solar collector, reaches the temperature and pressure required for sludge pyrolysis, and is gradually heated and pyrolyzed. After pyrolysis, the sludge is cooled by the cooling heat exchanger from the hot sludge tank and then enters the sludge dehydrator for mechanical dehydration, and the moisture content of the sludge can be reduced to 30-40%, so that it can be finally disposed of by incineration, land use, etc.

[0037] Among them, the medium passing through the inside of the heat collecting tube 3 is wet sludge; the heat collecting tube absorbs the solar rays reflected by the solar collector 4 to heat the sludge in the tube, and the heat collecting tube can operate at normal pressure or under pressure; the solar collector is composed of main components such as a sun-tracking driving mechanism, a collector main support structure and a reflector, which can track and focus solar rays to the surface of the above-mentioned heat collecting tube 3.

[0038] As a preferred embodiment, the solar collector 4 can be a linear focusing solar collector such as a linear Fresnel or trough collector. The solar collector can control the reflection angle according to the position of the sun to ensure that the system has a high heat collection efficiency. The solar collector 4 and the heat collecting tube 3 can be flexibly arranged on a vacant site or on the top of an existing building.

[0039] As a preferred embodiment, the hot sludge tank 5 is a pressure vessel, on which a pressure control valve is installed, which can adjust the system working pressure, control the sludge to be under certain temperature and pressure conditions, improve the pyrolysis effect and shorten the pyrolysis time. The hot sludge tank can also be discharged to a stirring device to homogenize the sludge.

[0040] The sludge pump 2 is a positive displacement pump such as a plunger pump or a screw pump, which provides power for sludge flow and system pressure control. Preferably, a necessary debris screening device is set in front of the sludge bin to ensure the smooth operation of the system; several levels of sludge pumps can be added to the system according to the project characteristics and specific layout conditions to ensure smooth process.

[0041] The cooling heat exchanger 6 is a closed surface heat exchanger, which can cool the sludge temperature to the temperature required by the subsequent dehydration device.

[0042] The sludge dehydrator 7 is a plate-and-frame dehydrator, a centrifugal dehydrator or other types of dehydrators, which can significantly reduce the moisture content of the sludge after pyrolysis and cooling to 30% to 40%.

[0043] The specific steps of the drying treatment method of the present invention are:

[0044] The wet sludge (water content of about 80%) produced by the sewage treatment process is stored in the sludge bin 1;

[0045] When the sunlight conditions are good during the day, the sludge is pressurized by the sludge pump 2 (such as a plunger pump) at a certain flow rate through the heat collecting pipe 3 and finally enters the hot sludge tank 5; during the flow of the sludge in the heat collecting pipe 3, it continuously absorbs the solar energy concentrated by the solar collector 4, reaches the temperature and pressure required for sludge pyrolysis, and gradually undergoes pyrolysis.

[0046] The microbial cells in the pyrolyzed sludge are broken and enter the cooling heat exchanger 6 from the hot sludge tank 5 for cooling. The pyrolyzed and cooled sludge finally enters the sludge dewatering machine 7 for the final stage of solid-liquid separation.

[0047] When the system pressure needs to be adjusted, it can be done by setting the pressure control valve on the hot sludge tank and selecting the appropriate working pressure according to the properties of the sludge.

[0048] When the drying effect needs to be adjusted, the flow rate of the sludge pump can also be adjusted to change the residence time of the sludge flowing through the system. Generally speaking, the slower the flow rate, the longer the sludge stays in the system, the higher the system working pressure, and the better the sludge pyrolysis effect.

[0049] Preferably, the sludge thermal energy obtained by cooling the heat exchanger or the heat pump device can be further utilized.

[0050] Preferably, the high-concentration organic wastewater separated by the sludge dewatering machine can be used for resource utilization, such as producing methane or increasing the organic matter concentration of the influent of the sewage treatment plant.

[0051] The device of the present application includes a sludge bin, a sludge pump, a heat collecting pipe, a solar collector, a hot sludge tank, a cooling heat exchanger, a sludge dehydrator and necessary connecting pipes and valves. The device can realize sludge drying and greatly reduce the operating cost of sludge pyrolysis drying.

[0052] The concentrated solar thermal sludge pyrolysis and drying treatment system is applicable to the field of municipal sludge drying technology. Through design, it cleverly utilizes the free solar thermal resources to pyrolyze sludge, with low operating costs. This invention patent is helpful to promote the progress and development of sludge drying treatment technology.

[0053] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A concentrated solar thermal sludge pyrolysis and drying treatment method, based on a concentrated solar thermal sludge pyrolysis and drying treatment system, characterized in that: The concentrated photothermal sludge pyrolysis and drying treatment system comprises: A sludge bin (1), wherein wet sludge is stored in the sludge bin (1); a sludge pump (2) is provided at the outlet of the sludge bin (1); A heat collecting pipe (3), wherein the heat collecting pipe (3) is connected to a sludge pump (2), and wet sludge is pumped into the heat collecting pipe (3) through the sludge pump (2); A solar thermal collector (4), wherein the heat collecting tube (3) is arranged on the upper part of the solar thermal collector (4), and the heat collecting tube (3) absorbs the solar rays reflected by the solar thermal collector (4) to pyrolyze the wet sludge in the tube; A hot sludge tank (5), the hot sludge tank (5) being in communication with the heat collecting pipe (3) and storing the wet sludge after pyrolysis; A cooling heat exchanger (6), wherein the cooling heat exchanger (6) is connected to the hot sludge tank (5) to cool the wet sludge; and a sludge dewatering machine (7), wherein the sludge dewatering machine (7) is connected to the cooling heat exchanger (6) to perform mechanical dewatering of wet sludge; The solar collector (4) comprises a driving mechanism, a collector main body support structure and a reflector, wherein the driving mechanism and the reflector are mounted on the collector main body support structure, and the reflector tracks and focuses the solar light onto the surface of the collector tube (3) under the drive of the driving mechanism; during the flow of the wet sludge in the collector tube (3), the wet sludge continuously absorbs the solar heat gathered by the solar collector (4) to reach the temperature and pressure required for sludge pyrolysis, and then gradually undergoes pyrolysis and enters the hot sludge tank (5); The solar thermal collector (4) is a line focusing type collector; the solar thermal collector (4) and the heat collecting tube (3) are arranged on an empty site or on top of a building; The concentrated photothermal sludge pyrolysis and drying treatment method comprises the following steps: The sludge pump (2) pressurizes the wet sludge and pumps it into the heat collecting pipe (3). During the flow of the wet sludge in the heat collecting pipe (3), the wet sludge continuously absorbs the solar heat gathered by the solar collector (4) to reach the temperature and pressure required for sludge pyrolysis. After pyrolysis gradually occurs, the wet sludge enters the hot sludge tank (5); After the pyrolysis, the microbial cells in the sludge are broken and enter the cooling heat exchanger (6) from the hot sludge tank (5) for cooling; The wet sludge after pyrolysis and cooling finally enters the sludge dewatering machine (7) for solid-liquid separation.

2. The method for treating sludge by pyrolysis and drying using concentrated solar thermal energy according to claim 1, characterized in that: The hot sludge tank (5) is a pressure vessel on which a pressure regulating valve is installed.

3. The method for treating sludge by pyrolysis and drying using concentrated solar thermal energy according to claim 1, characterized in that: The sludge pump (2) is a positive displacement pump.

4. The method for treating sludge by pyrolysis and drying using concentrated solar thermal energy according to claim 1, characterized in that: The cooling heat exchanger (6) is a closed surface heat exchanger.

5. The method for treating sludge by pyrolysis and drying using concentrated solar thermal energy according to claim 1, characterized in that: The sludge dewatering machine (7) is a plate-and-frame dewatering machine or a centrifugal dewatering machine.

6. The method for treating sludge by pyrolysis and drying using concentrated light and heat according to claim 1, characterized in that: When the system pressure needs to be adjusted, the appropriate working pressure is selected through the pressure control valve on the sludge tank (5); When it is necessary to adjust the drying effect, the flow rate of the sludge pump (2) is adjusted to change the residence time of the sludge flowing through the system.

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