CN109974445B

CN109974445B - Cement rotary kiln with high energy utilization rate

Info

Publication number: CN109974445B
Application number: CN201910224705.4A
Authority: CN
Inventors: 周文剑
Original assignee: Hubei Jinglan Cement Co ltd
Current assignee: HUBEI JINGLAN CEMENT Co.,Ltd.
Priority date: 2019-03-23
Filing date: 2019-03-23
Publication date: 2020-10-30
Anticipated expiration: 2039-03-23
Also published as: CN111947453A; CN109974445A

Abstract

The invention discloses a cement rotary kiln with high energy utilization rate, which comprises a rotary kiln, a rotary kiln body arranged on the rotary kiln and a support for supporting the kiln body; a waste heat recovery device is arranged on the rotary kiln; the waste heat recovery device comprises a heat collection cover arranged on the kiln body and a heat collection water pipe arranged in the heat collection cover; according to the invention, through the arrangement of the heat collection cover and the heat collection pipe, the effect of better absorbing heat dissipated by the kiln body is achieved, the secondary utilization of energy is realized, and the purposes of energy conservation and emission reduction are achieved.

Description

Cement rotary kiln with high energy utilization rate

Technical Field

The invention belongs to the technical field of industrial kilns, and particularly relates to a rotary cement kiln with high energy utilization rate.

Background

The rotary kiln is a rotary calcining kiln (commonly called rotary kiln) and belongs to building material equipment. The rotary kiln can be divided into a cement kiln, a metallurgical chemical kiln and a lime kiln according to different materials to be treated; the cement kiln is mainly used for calcining cement clinker and comprises a dry-process cement kiln and a wet-process cement kiln.

However, the rotary kiln consumes a large amount of energy in the working process, and dissipates a large amount of heat, thereby causing energy waste, and being not beneficial to environmental protection, energy conservation and emission reduction.

Disclosure of Invention

The invention provides a rotary cement kiln with high energy utilization rate by utilizing waste heat in order to overcome the defects of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme: a cement rotary kiln with high energy utilization rate comprises a rotary kiln, a rotary kiln body arranged on the rotary kiln and a support for supporting the kiln body; a waste heat recovery device is arranged on the rotary kiln; the waste heat recovery device comprises a heat collection cover arranged on the kiln body and a heat collection water pipe arranged in the heat collection cover; through the arrangement of the heat collection cover and the heat collection water pipe, the effect of absorbing heat dissipated from the kiln body is achieved, so that the effect of recovering waste heat is achieved, dissipated heat energy is better utilized, energy utilization is more sufficient, and the effects of energy conservation and emission reduction are achieved.

Further, the heat collecting water pipe comprises a lower layer heat collecting water pipe close to the kiln body, an upper layer heat collecting water pipe far away from the kiln body and a water pipe elbow for communicating the upper layer heat collecting water pipe with the lower layer heat collecting water pipe; the double-layer heat collecting water pipe plays a role in double heat absorption, so that the absorption efficiency is better and the absorption is more complete; and the upper and lower heat collecting water pipes are communicated through the water pipe elbow, so that the upper and lower heat collecting water pipes form convection, thereby realizing the heat circulating absorption and further better achieving the purpose of utilizing waste heat.

Further, a stainless steel plate is arranged on the lower layer of heat collecting water pipe, and a coating is arranged on one side, close to the kiln body, of the stainless steel plate; the coating is a high-absorptivity low-reflectivity coating; the metal has good heat conductivity, and through the setting of corrosion resistant plate, better heat conduction effect is played to when playing better effect of absorbing the waste heat, the setting of coating has further improved the absorption effect of thermal-arrest water pipe to the waste heat.

Further, a color steel plate is arranged on the upper layer heat collecting water pipe, and a ceramic fiber plate is arranged between the upper layer heat collecting water pipe and the color steel plate; the color steel plates are arranged, so that a good heat preservation effect is achieved, heat loss is avoided, the color steel plates surround the heat collection water pipe between the kiln body and the color steel plates, a semi-closed environment is formed, a better heat preservation effect is achieved, and the heat collection water pipe can absorb heat conveniently; the ceramic fiber plate has the effects of low thermal capacity and low thermal conductivity, keeps good mechanical strength after heating, has high heat-resistant strength and long service life, is attached to the surface of a hot upper layer heat collection water pipe, blocks the heat convection between the upper layer heat collection water pipe and cold air, has good heat preservation effect, is efficient, energy-saving, safe and environment-friendly; the coating is a high absorption and low reflection coating.

Furthermore, the lower layer heat collecting water pipe and the upper layer heat collecting water pipe are snake-shaped heat collecting water pipes made of seamless stainless steel water pipes; the snakelike heat collecting water pipes are attached to the stainless steel plate; through snakelike thermal-arrest water pipe's setting for the distance that rivers flowed through is longer, and the area of flowing through is bigger, thereby plays the effect of better absorption waste heat, and thermal-arrest water pipe's shape is unanimous with the corrosion resistant plate, and the corrosion resistant material mass energy plays better heat conduction effect, thereby has further strengthened the effect of absorbing the waste heat.

Further, a water inlet is formed in the upper layer of heat collecting water pipe, and a water outlet is formed in the lower layer of heat collecting water pipe; the water outlet is communicated with a water storage tank through a water pipe, a one-way valve is further arranged between the water pipe and the water storage tank, and the water pipe is wrapped with heat preservation cotton; the hot water flows into the water storage tank through the stainless steel water pipe, so that the hot water is convenient to collect and use, and the one-way valve arranged between the water pipe and the water storage tank can effectively prevent the hot water from flowing back into the heat collection cover due to the steam generated in the water storage tank.

Furthermore, the two heat collecting covers are arranged, the two heat collecting covers are communicated with a three-way pipe through a stainless steel corrugated pipe, and the three-way pipe is communicated with the water tower; by arranging the two heat collecting covers, the effect of better absorbing waste heat is achieved; through the setting of water tower again for the hydroenergy after being heated can be better stores up, and convenient to use simultaneously also makes the water in the hot water collecting pipe be cold water all the time, plays the effect of better absorption waste heat.

Further, a tail gas heating device is arranged on the side wall of the preheating chamber, and comprises a tail gas cover covered on the preheating chamber, a tail gas channel arranged between the tail gas cover and the preheating chamber, a tail gas pipe used for communicating the tail gas channel with the decomposing furnace, and a cleaning structure communicated with the tail gas channel; the preheating chamber is sealed in the tail gas cover through the tail gas cover, and the tail gas is introduced into the tail gas channel through the tail gas pipe, so that the tail gas with waste heat can heat the preheating chamber in an all-around manner, the temperature of the raw materials in the preheating chamber is increased, the subsequent processing of the raw materials is facilitated, the tail gas is reasonably utilized, the waste caused by heat dissipation is avoided, the tail gas is separated from the raw materials, the raw materials are prevented from being polluted by impurities in the tail gas, and the purity of the produced cement is ensured; and in order to prevent impurities in the tail gas from blocking the tail gas channel, a cleaning structure is also arranged for cleaning impurities such as dust, particles and the like remained in the tail gas hood, so that the normal work of the tail gas heating device is ensured.

Furthermore, the cleaning structure comprises a cleaning pipe communicated with the tail gas channel, a negative pressure pipe communicated with the cleaning pipe, a multi-layer filter screen bag arranged in the negative pressure pipe, a propeller blade rotatably arranged in the negative pressure pipe and a driving piece for driving the propeller blade to rotate; through driving piece drive propeller blade rotation, thereby form a negative pressure in the negative pressure pipe, make the air current flow in from the exit of tail gas passageway, flow out in the negative pressure pipe, thereby take the impurity in the tail gas passageway to get into the multilayer filter screen bag, when playing the effect of clearance tail gas passageway, avoided the in disorder of impurity to discharge, when playing the effect of environmental protection, also guaranteed that staff's is healthy, and prolonged the life of equipment.

In conclusion, the heat collecting cover and the heat collecting pipe are arranged, so that the heat collecting cover has a better effect of absorbing heat dissipated by the kiln body, secondary utilization of energy is realized, and the purposes of energy conservation and emission reduction are achieved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic perspective view of the exhaust hood of the present invention;

FIG. 3 is a schematic cross-sectional view of the exhaust hood of the present invention;

FIG. 4 is a schematic structural diagram of an exhaust gas heating apparatus according to the present invention;

FIG. 5 is a schematic structural view of a cleaning structure according to the present invention;

FIG. 6 is a schematic view of the hook and the slot of the present invention;

FIG. 7 is a schematic view of a slot structure according to the present invention;

FIG. 8 is a schematic view of the structure of the tail gas treatment system according to the present invention;

FIG. 9 is a top view of the spray assembly and biofiltration device of the present invention after exiting the layer of water permeable fabric;

FIG. 10 is a schematic structural diagram of a waste heat recovery device according to the present invention;

FIG. 11 is a schematic view of the connection between two heat collecting covers according to the present invention;

FIG. 12 is a schematic structural view of a lower layer heat collecting water pipe according to the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

As shown in fig. 1-12, a rotary cement kiln capable of reducing impurities comprises a rotary kiln 1, a decomposing furnace 18, a preheating chamber 19, a feeding device, a dust removing device, a tail gas treatment system, a cooling device and a milling device; the rotary kiln comprises a kiln body 11, a kiln head 12, a kiln tail 13 and a support 8; the kiln body is rotatably arranged on the bracket, and the bracket is provided with a driving device capable of driving the kiln body to rotate; the kiln body is arranged in an inclined manner, so that raw materials can move and be heated along the inclined kiln body conveniently, and tail gas generated by heating can also rise along the inclined pipeline conveniently and is discharged from a kiln head connected with the decomposing furnace; the decomposing furnace is connected with the preheating chamber, so that the raw materials preheated in the preheating chamber can enter the decomposing furnace; a feed inlet 14 is arranged above the preheating chamber.

In order to avoid the pollution of impurities in the tail gas to the raw materials caused by the direct contact of the tail gas and the raw materials, a tail gas heating device is arranged outside the preheating chamber and comprises a tail gas cover 41, a tail gas channel 42, a tail gas pipe 43 and a cleaning structure; the tail gas cover is arranged outside the preheating chamber, the inner surface of the lower end of the tail gas cover is welded with the outer surface of the preheating chamber, so that a tail gas channel is formed between the inner wall of the tail gas cover and the outer wall of the preheating chamber, a tail gas port 44 is formed in the tail gas channel, a tail gas pipe is arranged in the tail gas port and is in threaded connection with the tail gas port, the other end of the tail gas pipe is connected with the top of the decomposing furnace, so that a reaction cavity in the decomposing furnace is communicated with the tail gas channel, and tail gas is discharged into the tail gas channel through the tail gas pipe; in order to prevent impurities such as dust, particles and the like in the tail gas from being accumulated in the tail gas hood, the inner wall of the tail gas hood is provided with an arc-shaped inner wall 411, the shape of the outer wall of the preheating chamber is the same as that of the inner wall of the tail gas hood and is also an arc-shaped surface, and the curvature of the arc-shaped inner wall is gradually increased from top to bottom, so that the tail gas hood is in a shape with a small top and a big bottom, the impurities in the tail gas are prevented from being adhered to the upper side of the inner wall of the tail gas hood, the impurities remained in the tail gas hood are accumulated at the bottom; in order to reduce the impurity residue in the exhaust hood, the spiral pipeline 412 is arranged in the arc-shaped inner part, so that the tail gas introduced from the exhaust pipe forms a tornado which is coiled upwards along the spiral pipeline, the tail gas is more conveniently discharged, and the tornado can easily roll away the impurities, so that the impurities are prevented from being remained in the exhaust hood; and after the tail gas enters the tail gas hood, the preheating chamber is heated in all directions, the heating effect is better, and the raw materials are more fully preheated.

Specifically, the cleaning structure comprises a cleaning pipe 51, a cleaning assembly and an automatic valve; the cleaning component comprises a negative pressure pipe 52, a multi-layer filter screen bag 53, a propeller blade 54 and a driving piece 55; the driving member is a motor purchased in the market, which is the prior art, and therefore, the details are not described herein; the cleaning pipe is provided with a slot 511, the negative pressure pipe is inserted into the slot, and a sealing ring is arranged between the slot and the negative pressure pipe, so that the negative pressure pipe and the slot form tight fit to play a role in sealing; the multi-layer filter screen bag is arranged at one end of the negative pressure pipe close to the cleaning pipe and is connected with the negative pressure pipe in a buckling mode, so that the multi-layer filter screen bag can be taken out to clean the garbage after the multi-layer filter screen bag is filled with the garbage; the propeller blade is arranged on the right side of the multilayer filter screen bag and is connected with the output end of the motor, so that when the motor is started, the propeller blade can be driven to rotate, and the rotation of the propeller blade can form negative pressure in the negative pressure pipe, so that impurities in the tail gas cover are sucked into the multilayer filter screen bag; in order to avoid sucking the contents in the decomposing furnace and form a complete airflow channel, a valve is arranged on the tail gas pipe; when the valve is closed, airflow can only flow in from the gas outlet communicated with the tail gas channel, and when the airflow flows through the tail gas channel, cyclone from top to bottom is formed under the action of the spiral pipeline, so that the function of better cleaning impurities in the tail gas cover is achieved, and the impurities in the tail gas cover are rolled into the multilayer filter screen bag.

Specifically, the automatic valve comprises a valve 61, a threaded sleeve 62 and a transmission assembly, wherein the transmission assembly comprises a threaded rod 63, a first transmission gear 64, a transmission rod 65, a knob piece 66 and a second transmission gear 67; the valve is arranged on the cleaning pipeline, can move up and down and is used for opening and closing the cleaning pipeline; the threaded sleeve is welded on the valve and is in threaded connection with the threaded rod; the lower end of the threaded rod is connected with a cleaning pipe bearing; two clamping hooks 521 are installed at the left end of the negative pressure pipe, a longitudinal channel 512 for the clamping hooks to pass through and an arc-shaped channel 513 for the clamping hooks to rotate are formed in the slot 511, so that the clamping hooks can pass through the longitudinal channel and are connected with a knob piece, a clamping groove 661 matched with the clamping hooks is formed in the knob piece, and the hook parts of the clamping hooks can be embedded into the clamping grooves; the knob piece is arranged on the cleaning pipe and is connected with the cleaning pipe bearing, so that when the negative pressure pipe is inserted into the slot, the clamping hook is embedded into the clamping groove through the longitudinal channel, then the negative pressure pipe is rotated, the clamping hook can rotate along the arc-shaped channel to clamp the negative pressure pipe, the knob piece can rotate along with the negative pressure pipe under the matching of the clamping hook and the clamping groove, so that a second transmission gear meshed with the knob piece is driven to rotate, the second transmission gear drives a transmission rod connected with the knob piece to rotate, the transmission rod drives a first transmission gear connected with the knob piece to rotate, the first transmission gear drives a threaded rod meshed with the first transmission gear to rotate, the threaded rod drives a threaded sleeve connected with the threaded rod to ascend, and the valve is driven to ascend to open the cleaning pipe; on the contrary, when the negative pressure pipe is separated from the cleaning pipe, the valve is driven to descend to close the cleaning pipe, so that the problem of tail gas leakage caused by forgetting to close the cleaning pipe by a worker is solved while the operation of the worker is facilitated, and the effects of protecting the environment and the body health of the worker are achieved; and gear drive stable in structure, the transmission is accurate, long service life, the fault rate is low, more effectual use of guaranteeing the clearance structure.

Specifically, the tail gas treatment system comprises a condensing device, a spraying device and a filter device; the condensing unit includes a condenser 74 and an entrainment separator 71; the mist separator is arranged on the condenser; the spraying device comprises a spraying tower 72, an inlet 721 and an outlet 722; the filter device comprises an air inlet and a reaction tank 73; the reaction tank comprises a cement brick matrix layer 731, a permeable fabric layer 732 and a porous filler medium layer from bottom to top; a base of the reaction tank is built by cement bricks; the porous filler medium layer is made of PVC material and is used for filling reactants; the condenser comprises an upper tail gas cavity 741, a middle heat exchange cavity 742 and a lower conical cavity 743, wherein a tail gas inlet is formed in the side surface of the upper tail gas cavity, a dispersion hole is formed between the upper tail gas cavity and the middle heat exchange cavity, and a dispersion hole is also formed between the middle heat exchange cavity and the lower conical cavity; and the heat exchange tube nest 75 is installed in the heat exchange cavity of the middle part, and the heat exchange tube nest is communicated with the dispersion hole; a hot water outlet and a cold water outlet are formed in the side surface of the outer wall of the middle heat exchange cavity; the lower conical cavity is provided with a condensate outlet and an air outlet, and the air outlet is communicated with an inlet on the spraying device through a pipeline; the top of the upper tail gas cavity is provided with an acrylic plate to form a transparent window, a filter screen is arranged in a gas outlet of the lower conical cavity, a hot water outlet on the middle heat exchange cavity is connected with a hot water storage tank 76, and a cold water inlet on the middle heat exchange cavity is sequentially connected with a heat exchanger 77, a first water pump and a cooling tower 78; the hot water storage tank can be connected with a cooling tower (not shown) through a second water suction pump and a heat exchanger, so that water in the hot water storage tank can enter a cold water inlet through the cooling of the heat exchanger and the cooling tower; a valve is arranged between a cold water inlet on the middle heat exchange cavity and the heat exchanger, and a valve is arranged between the first water pump and the cooling tower; the first water pump and the second water pump are water pumps purchased in the market, which is the prior art, and therefore, the detailed description is omitted; the mist separator is connected with the dryer 79, the mist separator comprises a conical bottom and a filtering layer arranged inside, the front end of the waste gas inlet is a stainless steel pipe with dense air holes arranged in a matrix form, the surface of the stainless steel pipe is covered with filter cloth to prevent porous filler media from blocking the air holes, the thickness of the porous filler medium layer is 4 times of the sum of the thicknesses of a cement brick base layer 731, an inflatable brick base layer and a permeable fabric layer 732, the inflatable brick base layer is provided with a drainage pipeline, a top outlet 722 is connected with the waste gas inlet of the reaction tank, and the surfaces of the inflatable brick base layer and the wall body layer are coated with anti-corrosion layers; the inner wall of the spray tower 72 is provided with spray headers arranged in a matrix manner for spraying, the right side outside the spray tower 72 is provided with a switch valve, a booster pump and a water storage device which are communicated with the spray headers, the top of the water storage device is provided with the booster pump, the switch valve and the spray headers and used for spraying water in the water storage device to the upper surface of a porous packing medium layer of the reaction tank, so that the porous packing medium layer is always kept in a wet state, fungus propagation is facilitated, and effective decomposition of tail gas is promoted.

In order to avoid energy loss, a waste heat recovery device is arranged, specifically, a heat collecting cover 2 which is coaxially arranged with the kiln body is arranged above the kiln body, a heat collecting water pipe is arranged in the heat collecting cover, the heat collecting water pipe comprises an upper heat collecting water pipe 21 and a lower heat collecting water pipe 22, the lower heat collecting water pipe is arranged at the inner layer close to the kiln body 11, a stainless steel plate 25 is arranged at the outer layer of the lower heat collecting water pipe, one side of the stainless steel plate 25 close to the kiln body is coated with a coating, the side of the stainless steel plate far away from the kiln body is provided with the upper heat collecting water pipe 21, the outer layer of the upper heat collecting water pipe is provided with a color steel plate 27, a ceramic fiber plate 26 is also arranged between the upper heat collecting water pipe and the color steel plate, the ceramic fiber plate has the functions of low heat capacity and low heat conductivity, good mechanical strength is kept after heating, the heat collecting water pipe has high heat, the heat preservation effect is good, the efficiency is high, the energy is saved, and the safety and the environmental protection are realized; the coating is a high-absorptivity low-reflectivity coating; the heat collecting cover is in a semi-circular arc shape and is matched with the kiln body in shape; the heat collecting cover is covered above the kiln body, and keeps a distance with the kiln body to absorb the radiant heat generated by the kiln body due to high temperature and the heat generated by convection with cold air.

Specifically, the upper layer heat collecting water pipe 21 and the lower layer heat collecting water pipe 22 are connected by a water pipe elbow 23 to realize the cyclic utilization of water; the lower layer heat collecting water pipe 22 is a lower layer snake-shaped heat collecting water pipe, and the upper layer heat collecting water pipe 21 is an upper layer snake-shaped heat collecting water pipe; the upper-layer snakelike heat collecting water pipe and the lower-layer snakelike heat collecting water pipe are seamless stainless steel water pipes, and the shape of the upper-layer snakelike heat collecting water pipe and the shape of the lower-layer snakelike heat collecting water pipe are consistent with the arc shape of the stainless steel plate 25; seamless stainless steel water pipe is through bending the welding on corrosion resistant plate 25, and the snakelike hot water collecting pipe in upper strata leads to cold water and passes through the heat-conduction effect of corrosion resistant plate 25, absorbs corrosion resistant plate 25's waste heat, and the circulation is to the snakelike hot water collecting pipe in lower floor, and the radiant heat and the convection heat that fully absorb from the kiln body reach the purpose for the cooling of high temperature kiln body surface.

Specifically, the upper layer of snakelike heat collecting water pipe is provided with a water inlet 211, and the lower layer of snakelike heat collecting water pipe is provided with a water outlet 221; the water outlet 221 is connected with the water storage tank 9 through a water pipe, a one-way valve 91 is further installed between the water pipe and the water storage tank 9, and heat insulation cotton 92 is wrapped on the water pipe; the water pipe adopts a stainless steel water pipe, hot water flows into the water storage tank through the stainless steel water pipe, so that the collection and the use of the hot water are facilitated, and the check valve arranged between the water pipe and the water storage tank can effectively prevent the hot water from flowing back into the heat collection cover due to steam generated in the water storage tank.

Specifically, the heat collecting cover 2 is connected with the bracket 8 through bolts and nuts 24, so that the structure is stable and the disassembly is convenient; the support 8 comprises a support frame 81, pulley blocks 84 and a slide rail 82, the support frame 81 is in line-surface contact with the slide rail 82 through the pulley blocks 84, the pulley blocks 84 are axially arranged along the track of the slide rail 82, and a plurality of latches 83 for locking the pulley blocks 84 are further mounted on the slide rail 82; the lock catch is in a locking state when the rotary cement kiln normally works to prevent the support from moving axially, when the lock catch is opened, the support is horizontally moved, the part of the heat collection cover covering the kiln body can be overhauled, and the phenomena that the surface of the kiln body is cracked due to the fact that the kiln body is covered by the heat collection cover for a long time are avoided.

Because the kiln body is positioned in a burning zone with the highest temperature, two heat collecting covers 2 are arranged, the two heat collecting covers 2 are connected with a three-way pipe through a stainless steel corrugated pipe 28, and the three-way pipe is connected with a water tower 93; the two heat collecting covers 2 are adjacently arranged side by side coaxially, and the stainless steel corrugated pipe 28 can realize flexible connection between the two heat collecting covers.

It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. A cement rotary kiln with high energy utilization rate comprises a rotary kiln (1), a rotary kiln body (11) arranged on the rotary kiln (1), a support (8) for supporting the kiln body (11), a preheating chamber (19) and a decomposing furnace (18); the method is characterized in that: a waste heat recovery device is arranged on the rotary kiln (1); the waste heat recovery device comprises a heat collection cover (2) arranged on the kiln body (11) and a heat collection water pipe arranged in the heat collection cover (2);

the heat collecting water pipe comprises a lower layer heat collecting water pipe (22) arranged close to the kiln body (11), an upper layer heat collecting water pipe (21) arranged far away from the kiln body (11) and a water pipe elbow (23) used for communicating the upper layer heat collecting water pipe (21) with the lower layer heat collecting water pipe (22);

a stainless steel plate (25) is arranged on the lower layer heat collecting water pipe (22), and a coating is arranged on one side, close to the kiln body (11), of the stainless steel plate (25); the coating is a high-absorptivity low-reflectivity coating;

a color steel plate (27) is arranged on the upper layer heat collecting water pipe (21), and a ceramic fiber plate (26) is arranged between the upper layer heat collecting water pipe (21) and the color steel plate (27);

the lower layer heat collecting water pipe (22) and the upper layer heat collecting water pipe (21) are snake-shaped heat collecting water pipes made of seamless stainless steel water pipes; the snakelike heat collecting water pipes are attached to the stainless steel plate (25);

a water inlet (211) is formed in the upper layer heat collecting water pipe (21), and a water outlet (221) is formed in the lower layer heat collecting water pipe (22); the water outlet (221) is communicated with a water storage tank (9) through a water pipe, a one-way valve (91) is arranged between the water pipe and the water storage tank (9), and the water pipe is wrapped with heat insulation cotton (92);

the two heat collecting covers (2) are arranged, the two heat collecting covers (2) are communicated with a three-way pipe through a stainless steel corrugated pipe (28), and the three-way pipe is communicated with a water tower (93);

a tail gas heating device is arranged on the side wall of the preheating chamber (19), and comprises a tail gas cover (41) covered on the preheating chamber (19), a tail gas channel (42) arranged between the tail gas cover (41) and the preheating chamber (19), a tail gas pipe (43) used for communicating the tail gas channel (42) with the decomposing furnace (18), and a cleaning structure communicated with the tail gas channel (42);

the inner wall of the tail gas hood is provided with an arc-shaped inner wall (411), and the arc-shaped inner wall is provided with a spiral pipeline (412);

the cleaning structure comprises a cleaning pipe (51) communicated with the tail gas channel (42), a negative pressure pipe (52) communicated with the cleaning pipe (51), a multi-layer filter screen bag (53) arranged in the negative pressure pipe (52), a propeller blade (54) rotatably arranged in the negative pressure pipe (52), a driving piece (55) used for driving the propeller blade (54) to rotate and an automatic valve;

the automatic valve comprises a valve (61), a threaded sleeve (62) and a transmission assembly, wherein the transmission assembly comprises a threaded rod (63), a first transmission gear (64), a transmission rod (65), a knob piece (66) and a second transmission gear (67); the valve is arranged on the cleaning pipeline and can move up and down; the threaded sleeve is welded on the valve and is in threaded connection with the threaded rod, and the lower end of the threaded rod is connected with the cleaning pipe bearing;

two clamping hooks (521) are installed at the left end of the negative pressure pipe, a longitudinal channel (512) for the clamping hooks to penetrate through and an arc-shaped channel (513) for the clamping hooks to rotate are formed in the slot (511), and a clamping groove (661) matched with the clamping hooks is formed in the knob; the knob piece is arranged on the cleaning pipe and is connected with the cleaning pipe bearing;

when the negative pressure pipe inserts in the slot, the trip passes through in the longitudinal channel embedding draw-in groove, at this moment the negative pressure pipe of rotation again, the trip rotates along the arc passageway, block the negative pressure pipe, knob spare can rotate along with the negative pressure pipe under the cooperation of trip and draw-in groove, drive rather than intermeshing's second drive gear and rotate, second drive gear drives rather than the transfer line rotation of key-type connection again, the transfer line drives rather than the key-connected first drive gear and rotates, first drive gear drives rather than intermeshing's threaded rod and rotates, the threaded rod drives rather than threaded connection's threaded sleeve rises, it rises to drive the valve, open the clearance pipe.