Low-quality steam sludge dryer for thermal power plants and method of use thereof

Abstract

The application discloses a low-quality steam sludge dryer for a thermal power plant and a use method thereof, which comprises a sludge hydrothermal reaction device, the sludge hydrothermal reaction device has a closed inner cavity and a closed outer cavity, the inner cavity is used for loading sludge, and the top of the inner cavity is closed by an upper end cover; the outer cavity is communicated with a steam inlet device for leading low-quality steam into the outer cavity, a stirring device is arranged above the inner cavity, the output end of the stirring device enters the inner cavity after penetrating through the upper end cover and is used for stirring the sludge; the fixed end of the stirring device is fixedly connected with the upper end cover and is connected with a telescopic device for driving the stirring device to lift and lower. The low-quality steam produced by the thermal power plant is used as a power source, the best matching of a production process and the maximum utilization of resources are realized, the dried sludge is used as an economic coal type for deep peak regulation of the thermal power plant, the sludge solid waste treatment and capacity reduction are solved, the fuel cost of the thermal power plant is reduced, and the thermal power plant has more competitiveness when participating in the power market.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of municipal sludge incineration in thermal power plants, and in particular to a low-quality steam sludge dryer for thermal power plants and a method of using the same. BACKGROUND

[0002] The power system is the main force to achieve the double carbon target. Thermal power is gradually adjusting its positioning from base load power supply to standby power supply. Flexible and deep peaking has become the main work content of thermal power plants. Implementing coal blending and increasing the use of economic coal are effective means for thermal power plants to maximize benefits under low-load deep peaking. Municipal sludge is widely available and has a large output, and is a solid waste that needs to be disposed of urgently. By dewatering and upgrading municipal sludge into solid fuel for combustion in large thermal power plants, not only can the output of municipal sludge be rapidly reduced to help build a waste-free city, but also the fuel cost of thermal power plants can be reduced, making thermal power plants more competitive in deep peaking.

[0003] Thermal power plants are increasingly closely linked to municipal sludge. First, thermal power plants use a large amount of municipal water as production working medium, thereby protecting groundwater and surface water, and returning water to rivers. At the same time of using municipal water, the generated municipal sludge needs to be handled by itself, and if not utilized, it can only be landfilled. Combining the process flow of thermal power plants, furnace incineration is the best technical means to handle municipal sludge. Second, thermal power plants break the raw coal through the pulverizing system, and the coal powder blown into the furnace has a particle size of less than 300 μm. If the sludge is to be utilized by the thermal power plant, it needs to be dried and ground to a particle size of less than 300 μm, and then blown into the furnace with the primary air. However, the sludge has a high water content of about 80%, and after dewatering by the existing plate filter press, it is still in a lump shape. The sludge with a high water content not only causes the wall sticking and blockage of the coal feeder, but also cannot be transported by air, so it cannot be directly combusted and utilized by the thermal power plant. Third, hydrothermal technology is used for hydrothermal dewatering in the range of 150~180 ℃. At a lower hydrothermal temperature, while removing the water in the sludge, the organic matter inside the sludge is maximally maintained, and the fuel quality of the sludge is improved. Compared with conventional thermal drying, by increasing the initial pressure in the hydrothermal reactor to be higher than the saturation hydrothermal vapor pressure corresponding to the hydrothermal reaction temperature, the water vaporization inside the sludge can be avoided, thereby generating latent heat of vaporization, resulting in high energy consumption. The low-quality steam in the auxiliary steam header of the thermal power plant is the best power source for sludge hydrothermal dewatering. However, municipal sludge is not currently used for incineration in large thermal power plants, so it is necessary to invent a sludge dryer that is high in dewatering rate and has strong matching with the production process of the thermal power plant. SUMMARY

[0004] According to the above technical problem, the present application provides a low-quality steam sludge dryer for thermal power plants and a method of using the same.

[0005] The technical means adopted by the present application are as follows:

[0006] A low-quality steam sludge dryer for a thermal power plant comprises a sludge hydrothermal reaction device, which has a closed inner cavity and a closed outer cavity, the outer cavity is sleeved on the periphery of the inner cavity, the inner cavity is used for loading sludge, and the top of the inner cavity is closed by an upper end cover;

[0007] The outer cavity is communicated with a steam inlet device for introducing low-quality steam into the outer cavity, the low-quality steam of the steam inlet device comes from the auxiliary steam header of a thermal power unit, and the low-quality steam produced by the thermal power plant is used as a power source; a stirring device is arranged above the inner cavity, an output end of the stirring device penetrates through the upper end cover and enters the inner cavity, and the stirring device is used for stirring the sludge; a fixed end of the stirring device is fixedly connected with the upper end cover, and a telescopic device for driving the stirring device to ascend and descend is connected.

[0008] A drain pipe is connected to the bottom of the outer cavity.

[0009] Preferably, the sludge hydrothermal reaction device is divided into two parts connected in sequence, the upper part has a cylindrical outer cavity and a cylindrical inner cavity coaxially arranged in the cylindrical outer cavity, the lower part has a circular truncated cone outer cavity and a circular truncated cone inner cavity coaxially arranged in the circular truncated cone outer cavity, the inner diameter of the top of the circular truncated cone outer cavity matches the inner diameter of the bottom of the cylindrical outer cavity, and the inner diameter of the bottom of the circular truncated cone outer cavity is smaller than the inner diameter of the top of the circular truncated cone outer cavity; the inner diameter of the top of the circular truncated cone inner cavity matches the inner diameter of the bottom of the cylindrical inner cavity, and the inner diameter of the bottom of the circular truncated cone inner cavity is smaller than the inner diameter of the top of the circular truncated cone inner cavity.

[0010] Preferably, the top of the cylindrical outer cavity has a top sealing surface in the form of a ring, and the top sealing surface is used for sealing the top of the cylindrical outer cavity.

[0011] The bottom of the sludge hydrothermal reaction device has a bottom sealing surface in the form of a circle, and the bottom sealing surface is used for sealing the bottom of the circular truncated cone outer cavity and the circular truncated cone inner cavity.

[0012] The upper end cover covers the top of the cylindrical outer cavity and the cylindrical inner cavity, the inner edge of the top sealing surface has a sealing platform protruding upward, and the bottom of the upper end cover has a sealing groove matched with the sealing platform.

[0013] Preferably, the stirring device comprises a stirring motor located above the upper end cover, a stirring shaft coaxially arranged in the sludge hydrothermal reaction device and connected with the stirring motor, and stirring blades connected with the stirring shaft and located in the inner cavity, the stirring motor is the installation end thereof, and the stirring blades are the output end thereof.

[0014] Preferably, the top center of the upper end cover has a central hole for the stirring shaft to penetrate through, and the upper end cover is provided with a pressure sensor, a temperature sensor and a stamping exhaust pipe.

[0015] Preferably, the mounting end of the stirring device is connected with the telescopic device through a suspension device;

[0016] The telescopic device comprises a plurality of vertically arranged hydraulic telescopic rods,

[0017] The suspension device comprises a plurality of suspension beams matching the number of the hydraulic telescopic rods, and the plurality of suspension beams are evenly arranged around the center of the stirring device, one end of the suspension beam is fixedly connected with the stirring motor, the bottom of the other end of each suspension beam is connected with one of the hydraulic telescopic rods, and the upper surface of the upper end cover is fixedly connected with one end of the suspension beam close to the stirring device through a connecting rod; the hydraulic telescopic rod drives the suspension device, the stirring device and the upper end cover to lift after being extended.

[0018] Preferably, the sludge hydrothermal reaction device is seated in a supporting base;

[0019] The supporting base comprises a supporting body coaxially arranged with the sludge hydrothermal reaction device, the supporting body is in a cylindrical shape, and a plurality of supporting claws are evenly distributed around the axis of the supporting body, the sludge hydrothermal reaction device is seated on the supporting body, and the bottom is wrapped by the plurality of supporting claws.

[0020] Preferably, the steam inlet device is a low-quality steam circumferential steam inlet device, which comprises a main pipe coaxially arranged with the sludge hydrothermal reaction device and in a ring shape, and the main pipe has a steam inlet, the inner wall of the main pipe has a plurality of branch pipes arranged around the axis, one end of the branch pipe is in communication with the inside of the main pipe, and the other end is in communication with the outer cavity.

[0021] Preferably, the stamping exhaust pipe, the drain pipe and the steam inlet are provided with valves.

[0022] The application also discloses a use method of the low-quality steam sludge dryer for a thermal power plant, which comprises the following steps:

[0023] The telescopic device is extended, the stirring device is lifted at the same time, and the upper end cover is opened; the sludge filtered through the plate filter press is transferred into the inner cavity; the telescopic device is contracted, the stirring device is lowered at the same time, and the upper end cover is closed;

[0024] Air with a certain pressure is introduced into the inner cavity through the stamping exhaust pipe, so that the inner cavity has a certain initial pressure, the initial pressure is higher than the saturation temperature pressure of the low-quality steam, and thus the latent heat of vaporization of water in the sludge is avoided;

[0025] The stirring device is started, and the sludge is stirred;

[0026] The steam inlet device introduces low-quality steam in a steam auxiliary header of a thermal power plant into the outer cavity, and the low-quality steam exchanges heat with the sludge in the inner cavity to heat the sludge and cause a hydrothermal reaction, so that hydrothermal dewatering is performed; after the hydrothermal reaction is completed, the stirring device is closed, the stirring is stopped, the air in the inner cavity is discharged through the stamping exhaust pipe, and after the pressure is reduced, the drain pipe drains water;

[0027] The telescopic device is extended, the upper end cover is opened again, the sludge after hydrothermal dewatering is discharged, and after natural drying, the sludge is transferred to a coal shed for storage and used as boiler fuel.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The low-quality steam sludge dryer for a thermal power plant of the present application uses low-quality steam from a steam auxiliary header of a thermal power unit as a power source, so that the best matching of the production process and the maximum utilization of resources are realized; the hydrothermal drying realizes the resource utilization and quality improvement of the sludge, avoids the latent heat of vaporization, and has low energy consumption; the dried sludge is used as an economic coal type for deep peak regulation of the thermal power plant, solves the sludge solid waste treatment and capacity reduction, reduces the fuel cost of the thermal power plant, and makes the thermal power plant more competitive in the power market.

[0030] Based on the above reasons, the present application can be widely promoted in the field of municipal sludge incineration in a thermal power plant. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0032] FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant; Figure 1 FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant;

[0033] FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant; Figure 2 FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant;

[0034] FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant; Figure 3 FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant;

[0035] FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant; Figure 4 FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant;

[0036] FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant; Figure 5 FIG. 1 is a schematic diagram of a low-quality steam sludge dryer for a thermal power plant;

[0037] Figure 1 is a schematic view of the upper end cover; Figure 6 Figure 2 is a schematic view of the upper end cover;

[0038] Figure 3 is a sectional view of the upper end cover; Figure 7 Figure 4 is a sectional view of the upper end cover;

[0039] Figure 5 is a schematic view of the telescopic device, suspension device and stirring motor; Figure 8 Figure 6 is a bottom view of the telescopic device, suspension device and stirring motor;

[0040] Figure 7 is a schematic view of the telescopic device, suspension device and stirring motor; Figure 9 Figure 8 is a bottom view of the telescopic device, suspension device and stirring motor;

[0041] Figure 9 is a schematic view of the support base. Figure 10 Figure 10 is a schematic view of the support base.

[0042] In the figure: 1, sludge hydrothermal reaction device; 2, steam inlet device; 3, upper end cover; 4, telescopic device; 5, suspension device; 6, stirring device; 7, support base; 8, drain pipe electric valve; 9, drain pipe manual valve; 10, sealing groove; 11, cylindrical outer cavity; 12, cylindrical inner cavity; 13, circular table outer cavity; 14, circular table inner cavity; 15, top sealing surface; 16, bottom sealing surface; 17, sealing table surface; 18, drain pipe; 19, center hole; 20, pressure sensor; 21, temperature sensor; 22, stamping exhaust pipe; 23, exhaust electric valve; 24, stirring motor; 25, stirring shaft; 26, stirring blade; 27, main pipe; 28, steam inlet; 29, branch pipe; 30, hydraulic telescopic rod; 31, pad plate; 36, support body; 37, support claw; 38, steam inlet electric valve; 39, steam inlet manual valve. DETAILED DESCRIPTION

[0043] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] It is to be understood that the terms so far as the word "comprise" and / or "comprising", or "include" and / or "including" when used in this specification is / are used to express the inclusion of one or more steps, operations, elements, and / or components, but these articles do not exclude the other steps, operations, elements, and / or components.

[0046] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless specifically so stated. It is also to be understood that the dimensions of the various parts shown in the drawings are not necessarily to scale, and that for purposes of convenience and clarity in understanding the present application, common terms have been used for like components throughout. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but are to be considered as part of the description. In all examples shown and discussed herein, any specific values are to be interpreted as merely exemplary and not as a limitation on the scope of the exemplary embodiments. Thus, other examples of the exemplary embodiments can have different values. It is to be noted that like reference numerals and letters refer to like items in the drawings, and once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0047] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by orientation words such as "front, back, upper, lower, left, right", "transverse, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without the opposite indication, these orientation words do not indicate and imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application: the orientation words "inner, outer" refer to the inner and outer relative to the outline of each component itself.

[0048] For purposes of the description hereinafter, spatial relative terms, such as "above", "below", "upper", "lower", and the like, can be used to describe the relative position of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "up" other elements or features would then be oriented "below" or "down" the other elements or features. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative terms used herein interpreted accordingly.

[0049] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not connote any actual physical or logical relationship between the components being described. Rather, such words are used merely to distinguish one component from another.

[0050] As shown in the drawings, Figures 1-10 A low-quality steam sludge dryer for a thermal power plant includes a sludge hydrothermal reaction device 1, a steam inlet device 2, an upper end cover 3, an extension device 4, a suspension device 5, a stirring device 6, and a support base 7.

[0051] The sludge hydrothermal reaction device 1 has a closed inner cavity and a closed outer cavity, the outer cavity is sleeved on the periphery of the inner cavity, the inner cavity is used to load sludge, and the top of the inner cavity is closed by the upper end cover 3. The sludge hydrothermal reaction device 1 is divided into two parts connected in sequence, the upper part has a cylindrical outer cavity 11 and a cylindrical inner cavity 12 coaxially arranged with the cylindrical outer cavity 11, the lower part has a circular truncated cone outer cavity 13 and a circular truncated cone inner cavity 14 coaxially arranged with the circular truncated cone outer cavity 13, and the inner diameter of the top of the circular truncated cone outer cavity 13 matches the inner diameter of the bottom of the cylindrical outer cavity 13, and the inner diameter of the bottom is smaller than the inner diameter of the top. The inner diameter of the top of the circular truncated cone inner cavity 14 matches the inner diameter of the bottom of the cylindrical inner cavity 12, and the inner diameter of the bottom is smaller than the inner diameter of the top.

[0052] The top of the cylindrical outer cavity 11 has a top sealing surface 15 in the form of a ring, and the top sealing surface 15 is used to seal the top of the cylindrical outer cavity 11; the bottom of the sludge hydrothermal reaction device 1 has a bottom sealing surface 16 in the form of a circle, and the bottom sealing surface 16 is used to seal the bottom of the circular outer cavity 13 and the circular inner cavity 14; the upper end cover 3 covers the top of the cylindrical outer cavity 11 and the cylindrical inner cavity 12, the inner edge of the top sealing surface 16 has an upwardly protruding sealing platform 17, and the bottom of the upper end cover 3 has a sealing groove 10 matched with the sealing platform.

[0053] The bottom of the circular outer cavity 13 is provided with two water outlet pipes penetrating through the bottom sealing surface 16, and one of the water outlet pipes is vertically arranged, and the other is provided with a 45° elbow, and the two water outlet pipes are symmetrically arranged, and the end of the water outlet pipe is communicated with one end of the drain pipe 18, and the other end of the drain pipe 18 is provided with a drain pipe electric valve 8 and a drain pipe manual valve 9.

[0054] The top center of the upper end cover 3 has a center hole 19 for the stirring shaft of the stirring device 6 to pass through, and the upper end cover 3 is provided with a pressure sensor 20, a temperature sensor 21 and a stamping exhaust pipe 22, and the stamping exhaust pipe is provided with an exhaust pipe electric valve 23 at the end away from the upper end cover 3;

[0055] The stirring device 6 comprises a stirring motor 24 located above the upper end cover, a stirring shaft 25 coaxially arranged with the sludge hydrothermal reaction device 1 and connected with the stirring motor 24, and stirring blades 26 connected with the stirring shaft 25 and located in the inner cavity. The stirring motor 24 is the installation end, and the stirring blades 26 are the output end. The stirring shaft 25 passes through the center hole 19, the stirring blades 26 are located in the inner cavity for stirring, and the connection between the stirring shaft 25 and the center hole 19 has a sealing structure for sealing.

[0056] The steam inlet device 2 is a low-quality steam circumferential steam inlet device, which comprises a main pipe 27 coaxially arranged with the sludge hydrothermal reaction device 1 and in the form of a ring, and the main pipe 27 has a steam inlet 28, and the steam inlet 28 is provided with an air inlet electric valve 38 and an air inlet manual valve 39.

[0057] The inner wall of the main pipe 27 has six branch pipes 29 arranged around the axis, one end of the branch pipe 29 is communicated with the inside of the main pipe 27, and the other end is inclined downward by 15° and communicated with the cylindrical outer cavity 11 in the tangential direction. The main pipe 27 and the branch pipe 29 are both rigid pipes, so that the steam inlet device 2 and the sludge hydrothermal reaction device 1 are fixedly combined as a whole. The steam inlet device 2 is lower than the upper end cover 3.

[0058] The telescopic device 4 comprises three vertically arranged hydraulic telescopic rods 30, the bottom of the hydraulic telescopic rod 30 is provided with a pad 31, and each hydraulic telescopic rod 30 is provided with an oil inlet pipe and an oil return pipe.

[0059] The suspension device 5 comprises three suspension beams which are uniformly arranged around the center of the stirring motor 24, one end of the suspension beam is fixedly connected with the stirring motor 24, and the other end of each suspension beam is connected with one hydraulic telescopic rod 30.

[0060] The suspension beam comprises an upper end plate, an inclined end plate, a lower end plate and a supporting cylinder, the inclined end plate connects the upper end plate and the lower end plate, and the supporting cylinder is used for supporting the upper end plate.

[0061] The supporting base 7 comprises a supporting body 36 coaxially arranged on the sludge hydrothermal reaction device 1, the supporting body 36 is in a cylindrical shape, four supporting claws 37 are uniformly distributed around the axis of the supporting body 36, the sludge hydrothermal reaction device 1 is arranged on the supporting body 7, and the bottom of the sludge hydrothermal reaction device 1 is wrapped by the supporting claws 37, the supporting claw 37 comprises a vertical supporting plate, an inclined supporting plate and a horizontal supporting plate, the sludge hydrothermal reaction device 1 is matched with the bottom circular table structure of the sludge hydrothermal reaction device 1, and the drain pipe 18 is arranged at the gap between the adjacent two supporting claws 37.

[0062] The application further discloses a use method of the low-quality steam sludge dryer for the thermal power plant.

[0063] Assembling the device: the supporting base 7 is fixed on the horizontal ground plane; the sludge hydrothermal reaction device 1 is vertically hung into the supporting base 7 from top to bottom; the sludge hydrothermal reaction device 1 is coaxially arranged with the supporting base 7; the four supporting claws 37 of the supporting base 7 firmly hold the sludge hydrothermal reaction device 1, so that the sludge hydrothermal reaction device 1 is tightly fixed, and the top sealing surface 15 of the sludge hydrothermal reaction device 1 is horizontal; the horizontal supporting plate of each supporting claw 37 is tightly attached to the bottom sealing surface 16 of the sludge hydrothermal reaction device 1; the inclined supporting plate of each supporting claw 37 is tightly attached to the inclined outer wall surface of the circular table outer cavity 13; the vertical supporting plate of each supporting claw 37 is attached to the vertical outer wall surface of the cylindrical outer cavity 11; and the drain pipe 18 of the sludge hydrothermal reaction device 1 is arranged in the gap between the supporting claws 37.

[0064] The telescopic device 4 is arranged at the periphery of the hydrothermal reaction device 1, three hydraulic telescopic rods 30 are arranged at equal intervals along the circumference, and the movable rods thereof are connected with three suspension beams of the suspension device 5; after the connection, the telescopic device 4 and the suspension device 5 are an integral whole; the three suspension beams of the suspension device 5 are connected with the upper end cover 3 through three connecting rods; after the connection, the telescopic device 4, the suspension device 5, the stirring motor 6 and the upper end cover 3 are an integral whole; the movable rods of the three hydraulic telescopic rods 30 move up and down, drive the suspension device 5 to move up and down together, and thus the upper end cover 3 is opened or closed;

[0065] Before work: the movable rods of the three hydraulic telescopic rods 30 move upwards, drive the suspension device 5 to move upwards together, and open the upper end cover 3; the sludge filtered through the plate filter press is transferred into the inner cavity of the sludge hydrothermal reaction device 1; the movable rods of the three hydraulic telescopic rods 30 move downwards, drive the suspension device 5 to move downwards together, and close the upper end cover 3; a certain pressure is maintained in the oil return pipe of the hydraulic telescopic rod 30, a pre-tightening force is provided, and thus the sealing effect of the upper end cover 3 and the sludge hydrothermal reaction device 1 is achieved, and the leakage of reaction products in the hydrothermal reaction process is prevented; the drain manual valve 9 of the sludge hydrothermal reaction device 1 and the steam inlet manual valve 39 of the steam inlet device 2 are kept open; the steam outlet electric valve 39 on the upper end cover 3 is opened, instrument compressed air with initial pressure is introduced into the inner cavity of the sludge hydrothermal reaction device, the initial pressure of the compressed air is higher than the saturated water vapor pressure corresponding to the low-quality steam, so as to prevent the water in the sludge from being vaporized and to prevent the latent heat of vaporization from causing high energy consumption; after the introduction of air is completed, the steam outlet electric valve 39 is closed;

[0066] During work: the stirring motor 24 is started, drives the stirring blade 26 to stir the sludge, and thus the heat transfer and mass transfer are strengthened; the steam inlet electric valve 38 on the steam inlet device 2 is opened, and low-quality steam from the auxiliary steam header of the thermal power plant is introduced; after the low-quality steam flows through the main pipe 27, it enters the six branch pipes 29, is inclined downward by 15° along the tangential direction, and enters the outer cavity of the sludge hydrothermal reaction device 1; the low-quality steam exchanges heat with the sludge in the inner cavity in the outer cavity, the sludge is heated, the hydrothermal reaction occurs, and thus the hydrothermal dewatering is performed; the parameters of the low-quality steam and the hydrothermal reaction time are determined according to the sludge dewatering efficiency and fuel characteristics;

[0067] After the hydrothermal reaction is completed, the steam inlet electric valve 38 on the steam inlet device 2 is closed, and the low-quality steam is cut off; the steam outlet electric valve 23 on the upper end cover 3 is opened, and the air in the inner cavity of the sludge hydrothermal reaction device 1 is discharged; the drain electric valve 8 on the drain pipe 18 of the sludge hydrothermal reaction device 1 is opened, and the water is drained; the stirring motor 24 is closed, and the stirring is stopped; the movable rods of the three hydraulic telescopic rods 30 move upwards, drive the suspension device 5 to move upwards together, and the upper end cover 3 is opened again; the sludge after the hydrothermal dewatering in the inner cavity is discharged, is naturally dried, is transferred to the coal shed for storage, and is used as boiler fuel.

[0068] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-quality steam sludge dryer for a thermal power plant, characterized by, The sewage sludge hydrothermal reaction device comprises a closed inner cavity and a closed outer cavity, the outer cavity is sleeved on the periphery of the inner cavity, the inner cavity is used for loading sewage sludge, and the top of the inner cavity is closed by an upper end cover; The outer cavity is communicated with a steam inlet device for introducing low-quality steam into the outer cavity, the low-quality steam is low-quality steam produced by a thermal power plant, the upper portion of the inner cavity is provided with a stirring device, the output end of the stirring device enters the inner cavity through the upper end cover and is used for stirring the sewage sludge, the fixed end of the stirring device is fixedly connected with the upper end cover, and the fixed end is connected with a telescopic device for driving the stirring device to ascend and descend; The upper end cover is provided with a stamping exhaust pipe, and the bottom of the outer cavity is connected with a drain pipe. The stirring device comprises a stirring motor located above the upper end cover, a stirring shaft coaxially arranged with the sewage sludge hydrothermal reaction device and connected with the stirring motor, and stirring blades connected with the stirring shaft and located in the inner cavity, the stirring motor is provided with a mounting end, and the stirring blades are provided with an output end. The top center of the upper end cover is provided with a central hole through which the stirring shaft passes, and the upper end cover is provided with a pressure sensor and a temperature sensor; The stirring shaft passes through the central hole, the stirring blades are located in the inner cavity for stirring, and the connection between the stirring shaft and the central hole is provided with a sealing structure for sealing. The mounting end of the stirring device is connected with the telescopic device through a suspension device. The telescopic device comprises a plurality of vertically arranged hydraulic telescopic rods, The suspension device comprises a plurality of suspension beams matched with the number of the hydraulic telescopic rods, the suspension beams are uniformly arranged around the center of the stirring device, one end of each suspension beam is fixedly connected with the stirring device, and the other end of each suspension beam is connected with one of the hydraulic telescopic rods. The sewage sludge hydrothermal reaction device is divided into two parts connected in sequence, the upper part comprises a cylindrical outer cavity and a cylindrical inner cavity coaxially arranged with the cylindrical outer cavity, the lower part comprises a circular table outer cavity and a circular table inner cavity coaxially arranged with the circular table outer cavity, the inner diameter of the top of the circular table outer cavity is matched with the inner diameter of the bottom of the cylindrical outer cavity, and the inner diameter of the bottom of the circular table outer cavity is smaller than the inner diameter of the top of the circular table outer cavity.

2. A low quality steam sludge dryer for thermal power plants as claimed in claim 1 wherein: The top of the cylindrical outer cavity is provided with a ring-shaped top sealing surface, and the top sealing surface is used for sealing the top of the cylindrical outer cavity.

3. A low quality steam sludge dryer for use in a thermal power plant according to claim 2, characterized in that: The bottom of the sewage sludge hydrothermal reaction device is provided with a circular bottom sealing surface, and the bottom sealing surface is used for sealing the bottom of the circular table outer cavity and the circular table inner cavity. The upper end cover covers the top of the cylindrical outer cavity and the cylindrical inner cavity, the inner edge of the top sealing surface is provided with a sealing table surface protruding upward, and the bottom of the upper end cover is provided with a sealing groove matched with the sealing table surface. The sewage sludge hydrothermal reaction device is arranged in a supporting base.

4. A low quality steam sludge dryer for thermal power plants as claimed in claim 1 wherein: ​ The support base comprises a support body coaxially arranged in the sludge hydrothermal reaction device, the support body is in a cylindrical shape, and a plurality of support claws are uniformly distributed around the axis of the support body, the sludge hydrothermal reaction device is arranged on the support body, and the bottom is wrapped by the plurality of support claws.

5. A low quality steam sludge dryer for thermal power plants as claimed in claim 1 wherein: The steam inlet device is a low-quality steam circumferential steam inlet device, which comprises a main pipe coaxially arranged in the sludge hydrothermal reaction device and in an annular shape, and the main pipe has a steam inlet, and the inner wall of the main pipe has a plurality of branch pipes arranged around the axis, one end of the branch pipe is in communication with the inside of the main pipe, and the other end is in communication with the outer cavity.

6. The method of using a low-quality steam sludge dryer for a thermal power plant according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: The telescopic device is extended, driving the stirring device to rise, and at the same time, the upper end cover is opened; The sludge filtered by the plate filter press is transferred to the inner cavity; The telescopic device is retracted, driving the stirring device to descend, and at the same time, the upper end cover is closed; Air with a certain pressure is introduced into the inner cavity through the stamping exhaust pipe, so that the inner cavity has a certain initial pressure, the initial pressure is higher than the saturation temperature pressure of low-quality steam, and thus the latent heat of vaporization of water in the sludge is avoided; The stirring device is started to stir the sludge; The steam inlet device introduces low-quality steam in the auxiliary steam header of the thermal power plant into the outer cavity, the low-quality steam exchanges heat with the sludge in the inner cavity in the outer cavity, the sludge is heated, and hydrothermal reaction occurs, so that hydrothermal dewatering is carried out; after the hydrothermal reaction is completed, the stirring device is closed, the stirring is stopped, the air in the inner cavity is discharged through the stamping exhaust pipe, and after the pressure is reduced, the drain pipe drains water; The telescopic device is extended, the upper end cover is opened again, the sludge after hydrothermal dewatering is discharged, and after natural drying, it is transferred to the coal shed for storage and used as boiler fuel.

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