CN219083703U - Steam quality re-upgrading system of rotary kiln - Google Patents

Abstract

The embodiment of the application provides a rotary kiln steam quality is upgrading system again, including the rotary kiln that communicates in proper order, kiln hood and grate cooler, kiln hood top is connected with kiln hood boiler, be provided with one-level superheater and second grade superheater in the kiln hood boiler, rotary kiln externally mounted has the barrel evaporimeter, the steam-water mixture that kiln hood water-cooled wall and barrel evaporimeter preheated back produced gets into the steam pocket and carries out steam-water separation, steam that the separation obtained mixes with the produced steam from AQC exhaust-heat boiler and SP exhaust-heat boiler after through one-level superheater is overheated, concentrated transport carries out steam quality in the second grade superheater again and upgrades, high temperature radiant heat with the rotary kiln being difficult to utilize is retrieved, and will only be used for pure low temperature waste heat power generation's AQC exhaust-heat boiler and SP exhaust-heat boiler originally, can obtain the high quality steam of medium temperature middling pressure after mixing and second grade overheated, power generation efficiency has been improved greatly, and is applicable to the rotary kiln and comprehensively utilizes the field.

Description

Steam quality re-upgrading system of rotary kiln

Technical Field

The application relates to the field of comprehensive utilization of rotary kiln waste heat, in particular to a rotary kiln steam quality re-upgrading system.

Background

The prior novel dry cement clinker production line utilizes the heat of hot air extracted from an exhaust port of a kiln head grate cooler of the prior production line and flue gas exhausted by a primary preheater, and the heat is changed into the enthalpy of steam through an AQC waste heat boiler and an SP waste heat boiler to carry out pure low-temperature waste heat power generation.

On the other hand, when the rotary kiln cylinder and the kiln head cover work, the shell can generate a large amount of high-temperature radiation waste heat, and the high temperature of the radiation waste heat can cause great adverse effect on the working environment of workers, so that the service life of the thermal main equipment can be shortened, and expensive high-temperature resistant materials are required to be frequently used and replaced for insulation protection, thereby increasing the additional cost; and because the high-temperature radiant heat cannot be absorbed and utilized, the high-temperature heat carried by the high-temperature radiant heat is wasted, so that the thermal efficiency of the whole thermal system is reduced.

Disclosure of Invention

In order to solve one of the above technical drawbacks, an embodiment of the present application provides a steam quality re-upgrading system for a rotary kiln.

According to the first aspect of the embodiment of the application, a rotary kiln steam quality upgrading system is provided, including rotary kiln, kiln hood and grate cooler that communicate in proper order, kiln hood top is connected with kiln hood boiler, be equipped with the water-cooling wall on the kiln hood boiler casing, the output of water-cooling wall is connected with the steam drum, a plurality of barrel evaporators are installed along the axial to rotary kiln barrel outside, the output and the steam drum of barrel evaporators are connected, install one-level super heater and second grade super heater in the kiln hood boiler, the play vapour end of steam drum links to each other with the input of one-level super heater, the output of one-level super heater is connected with the steam collecting box, the output of steam collecting box links to each other with the input of second grade super heater, the output of second grade super heater is connected with the steam turbine.

Further, the steam generator also comprises an AQC waste heat boiler and an SP waste heat boiler, and steam output ends of the AQC waste heat boiler and the SP waste heat boiler are respectively connected with the input end of the steam collecting box.

Further, the water inlet of the steam drum is connected with a water pump, two water outlets of the steam drum are respectively connected with the water-cooled wall and the input end of the barrel evaporator through a descending pipe and a descending pipe group, and the two input ends of the steam drum are respectively connected with the water-cooled wall and the output end of the barrel evaporator through a ascending pipe and a ascending pipe group.

Further, the rotary kiln further comprises an air cooling system, the air cooling system comprises a barrel evaporator sleeved outside the rotary kiln and a heat insulation layer sleeved outside the barrel evaporator, an air outlet and an air inlet penetrating through the barrel evaporator and the heat insulation layer are respectively formed in the bottom and the top of the air cooling system, and a fan is arranged at the air inlet.

Further, the barrel evaporator comprises two evaporator tube sets which are sleeved on the rotary kiln after being buckled, the heat insulation layer comprises two heat insulation modules which are sleeved on the barrel evaporator after being buckled, and the barrel evaporator tube sets positioned on the same side and the heat insulation modules are connected through a connecting piece.

Further, a temperature detection device is arranged at the outlet of the secondary superheater, and a desuperheater is arranged in the steam collecting box corresponding to the temperature detection device.

Further, the bottom of the kiln head cover boiler is higher than the rotary kiln mouth and the tertiary air pipe, the kiln head cover boiler is communicated with the kiln head cover, and an air outlet is not arranged in the kiln head cover boiler.

Further, the heat insulation module is externally connected with an air cooling system shell, the air cooling system shell and the heat insulation module are arranged at intervals and are connected through a connecting piece, openings are formed in the air cooling system shell corresponding to the air outlet and the air inlet, and the air cooling system shell is connected with a connecting support.

By adopting the rotary kiln steam quality re-upgrading system provided by the embodiment of the application, a plurality of cylinder evaporators are sleeved outside the rotary kiln to recover the radiation waste heat generated by the rotary kiln shell, so that a preheated steam-water mixture is obtained; a kiln head hood boiler is arranged above a kiln head hood, a primary superheater and a secondary superheater are arranged above the inside of the kiln head hood boiler, and radiation waste heat in the kiln head hood is recovered; the steam generated by the AQC waste heat boiler and the SP waste heat boiler is mixed with the preheated steam after primary superheating, the mixed superheated steam is subjected to secondary superheating to obtain medium-temperature medium-pressure or medium-temperature low-pressure high-quality steam for power generation, the high-temperature radiation waste heat of the rotary kiln and the kiln hood shell which are difficult to utilize is recovered, the AQC waste heat boiler and the SP waste heat boiler which are originally only used for pure low-temperature waste heat power generation can be obtained after mixing and secondary superheating, and the power generation efficiency is greatly improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

fig. 1 is a schematic structural diagram of a steam quality re-upgrading system of a rotary kiln according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of an air cooling system according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a tube set and a heat insulation module of a cylinder evaporator according to an embodiment of the present disclosure;

wherein 10 is the rotary kiln, 20 is the kiln hood, 30 is the grate cooler, 40 is the kiln hood boiler, 401 is the water-cooled wall, 402 is the primary superheater, 403 is the secondary superheater, 404 is the downcomer, 405 is the riser, 406 is the temperature detecting device, 50 is the steam drum, 501 is the water pump, 60 is the barrel evaporator, 601 is the downer group, 602 is the riser group, 603 is the evaporator tube group, 70 is the vapor collecting box, 701 is the desuperheater, 80 is the steam turbine, 90 is the air cooling system, 901 is the insulating layer, 902 is the air outlet, 903 is the air inlet, 904 is the fan, 905 is the insulating module, 906 is the linking bridge.

Description of the embodiments

In order to make the technical solutions and advantages of the embodiments of the present application more apparent, the following detailed description of exemplary embodiments of the present application is given with reference to fig. 1 to 3, and it is apparent that the described embodiments are only some of the embodiments of the present application, not exhaustive of all the embodiments. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

In the process of realizing the application, the inventor finds that the prior novel dry cement clinker production line utilizes hot air extracted from an exhaust port of a kiln head grate cooler of the prior production line and heat of flue gas exhausted by a primary preheater, and pure low-temperature waste heat power generation is performed by changing an AQC waste heat boiler and an SP waste heat boiler into heat of steam.

On the other hand, when the rotary kiln and the kiln head cover work, the shell can generate a large amount of high-temperature radiation waste heat, and the high temperature of the radiation waste heat can cause great adverse effect on the working environment of workers, so that the service life of the thermal main body equipment can be shortened, and expensive high-temperature resistant materials are required to be frequently used and replaced for insulation protection, thereby increasing the additional cost; and because the high-temperature radiant heat cannot be absorbed and utilized, the high-temperature heat carried by the high-temperature radiant heat is wasted, so that the thermal efficiency of the whole thermal system is reduced.

In view of the above problems, a first aspect of the embodiments of the present application provides a rotary kiln steam quality re-upgrading system (Steam quality to upgrading of system, simply called squis, in fact, a rotary kiln steam quality re-upgrading system in the present utility model may also be called a rotary kiln steam multi-stage concentrated superheating system), including a rotary kiln 10, a kiln head 20 and a grate cooler 30 that are sequentially communicated, a kiln head boiler 40 (code FRZ) is connected to the top of the kiln head 20, the bottom of the kiln head boiler 40 is higher than the height of a rotary kiln mouth and a tertiary air duct, the kiln head boiler 40 is communicated with the kiln head boiler 20, and no air outlet is provided in the kiln head boiler 40, the design is adopted in order to avoid the influence of the kiln head boiler 40 on the tertiary air and the secondary air of the production system, i.e. the tertiary air and the secondary air of the production system do not flow into the kiln head boiler 40, the kiln head cover boiler 40 absorbs radiation waste heat in the kiln head cover 20 by utilizing the black hole principle, a water cooling wall 401 is arranged on a shell of the kiln head cover boiler 40, an output end of the water cooling wall 401 is connected with a steam drum 50, a plurality of barrel evaporators 60 (TZ codes) are axially arranged outside a barrel of the rotary kiln 10, the barrel evaporators 60 are arranged at positions of the barrel of the rotary kiln 10, the temperature of the barrel evaporators 60 is high, output ends of the barrel evaporators 60 are connected with the steam drum 50, a primary superheater 402 and a secondary superheater 403 are arranged in the kiln head cover boiler 40, a steam outlet end of the steam drum 50 is connected with an input end of the primary superheater 402, an output end of the primary superheater 402 is connected with a steam collecting box 70, an output end of the steam collecting box 70 is connected with an input end of the secondary superheater 403, and an output end of the secondary superheater 403 is connected with a steam turbine 80.

Specifically, the cylindrical evaporator 50 absorbs the radiant waste heat emitted by the rotary kiln 10, the water cooling wall 401 on the kiln hood boiler 40 absorbs the radiant waste heat in the kiln hood 20, the two components respectively obtain steam-water mixtures, the steam-water mixtures are sent into the steam drum 50 to be mixed and subjected to water-steam separation, and the steam obtained after separation is subjected to secondary superheating by the primary superheater 402 and the secondary superheater 403 to obtain medium-temperature medium-pressure steam or medium-temperature low-pressure steam, and the medium-temperature medium-pressure steam or the medium-temperature low-pressure steam is sent to the steam turbine 80 to be used for power generation.

Further, the steam generator further comprises an AQC waste heat boiler and an SP waste heat boiler, and steam output ends of the AQC waste heat boiler and the SP waste heat boiler are respectively connected with an input end of the steam collecting box 70.

Specifically, the steam-water mixture obtained from the cylindrical evaporator 50 and the water cooling wall 401 is mixed and separated by the steam drum 50, the steam temperature obtained after the superheating of the primary superheater 402 is similar to the steam temperature generated by the AQC waste heat boiler and the SP preheating boiler, the steam-water mixture is mixed by the steam collecting box 70, enters the secondary superheater 403 for secondary superheating, and the steam quality is upgraded again, so that medium-temperature medium-pressure steam or medium-temperature low-pressure steam is obtained and sent to the steam turbine 80 for power generation.

Further, the water inlet of the steam drum 50 is connected with a water pump 501, the water pump 501 is connected with deoxygenated water after softening treatment, two water outlets of the steam drum 50 are respectively connected with the water-cooled wall 401 and the input end of the barrel evaporator 60 through a descending pipe 404 and a descending pipe group 601, and two input ends of the steam drum 50 are respectively connected with the water-cooled wall 401 and the output end of the barrel evaporator 60 through an ascending pipe 405 and an ascending pipe group 602.

The steam drum 50 not only can perform steam-water separation, but also is respectively responsible for providing heat exchange medium for the water-cooled wall 401 and the barrel evaporator 60 for circulation; the softened deoxidized water is heated to 106 ℃ through a low-temperature economizer and then heated to 170-180 ℃ through a high-temperature economizer, and can be used as the supplementing water of the steam drum 50.

Further, the rotary kiln further comprises an air cooling system 90, wherein the air cooling system 90 comprises a barrel evaporator 60 sleeved outside the rotary kiln 10 and a heat insulation layer 901 sleeved outside the barrel evaporator 60, an air outlet 902 and an air inlet 903 penetrating through the barrel evaporator 60 and the heat insulation layer 901 are respectively formed in the bottom and the top of the air cooling system 90, and a fan 904 is arranged at the air inlet 903.

Specifically, when the thermal plant is operating normally, the drum evaporator 60 absorbs, on the one hand, the radiant waste heat from the high temperature section of the drum of the rotary kiln 10; on the other hand, the fan 904 inputs external cold air into the air cooling system 90 through the air inlet 903, and the external cold air passes through the cylinder of the rotary kiln 10, so that the local overheat area generated by the high temperature of clinker at the bottom of the cylinder of the rotary kiln 10 is cooled, the heated air continues to be collected and discharged to the air outlet 902 along the gap between the cylinder of the rotary kiln 10 and the cylinder evaporator 60 and the gap between the cylinder evaporator 60 and the heat insulation layer 901 respectively, in the process, the heated air transfers heat between the cylinder of the rotary kiln 10 and the cylinder evaporator 60 to form convection heat transfer, and the temperature of each area of the cylinder of the rotary kiln 10 gradually tends to be stable while the heat loss is taken away by the fan 203, so that each area of the cylinder evaporator 60 is heated uniformly, the heat exchange medium in the cylinder evaporator 60 is ensured to be heated uniformly and sufficiently, and the yield of the steam-water mixture of the cylinder evaporator 60 is improved.

Further, the barrel evaporator 60 comprises two evaporator tube sets 603 which are sleeved on the rotary kiln 10 after being buckled, the heat insulation layer 901 comprises two heat insulation modules 905 which are sleeved on the barrel evaporator 60 after being buckled, and the barrel evaporator tube sets 603 and the heat insulation modules 905 which are positioned on the same side are connected through connecting pieces.

Specifically, the evaporator tube set 603 and the heat insulation module 905 on the same side are integrally arranged, the heat insulation module 905 is externally connected with an air cooling system 90 shell, the air cooling system 90 shell and the heat insulation module 905 are arranged at intervals and are connected through a connecting piece, openings are formed in the positions, corresponding to the air outlet 902 and the air inlet 903, of the air cooling system 90 shell, a connecting bracket 906 arranged on the ground is adopted to fix an integrated structure, which is positioned on the same side and consists of the evaporator tube set 603, the heat insulation module 905 and the air cooling system 90 shell, on two sides of the rotary kiln 10, the integrated structure is connected through the connecting piece and then sleeved on the rotary kiln 10, and then the assembly of the air cooling system 90 can be completed;

the adoption of the integrated structure divides the air cooling system 90 into the left module and the right module, on one hand, because the air outlet 902 and the air inlet 903 which are positioned at the top and the bottom of the air cooling system 90 are reserved, on the other hand, the design can bring the advantages of convenient disassembly and maintenance cost reduction, if a certain evaporator tube group 603 is damaged and needs to be replaced, the integrated structure at one side is detached from the connecting bracket 906 after the connection of the left and the right integrated structures is released, and the whole device is not required to be detached and replaced like a traditional heat exchange device, so that a great amount of maintenance cost is saved.

Further, a temperature detecting device 406 is arranged at the outlet of the secondary superheater 403, and a desuperheater 701 is arranged in the steam header 70 corresponding to the temperature detecting device.

The temperature detection device 406 is used for monitoring the steam temperature at the outlet of the secondary evaporator 403 in real time, the desuperheater 701 is used for cooling the mixed superheated steam in the steam collecting box 70 after receiving the cooling instruction, the temperature detection device 406 and the desuperheater 701 together form an automatic control system, so that the steam temperature at the outlet of the secondary evaporator 403 is kept within the rated temperature range of the steam turbine 80 when the steam quality is upgraded again, and the steam quality is maximized within the rated working temperature of the steam turbine 80.

The embodiment of the application also provides a use method for steam quality re-upgrading of the rotary kiln, which comprises the following steps:

s10, preheating: the water pump 601 supplies the treated low-temperature deoxidized water to the steam drum 50, the steam drum 50 respectively conveys the low-temperature deoxidized water into the water-cooled wall 401 and the barrel evaporator 60 through the descending pipe 404 and the descending pipe group 601, and the kiln head cover 20 and the high-temperature radiation waste heat of the rotary kiln 10 respectively heat the low-temperature deoxidized water in the water-cooled wall 401 and the barrel evaporator 60 to form a steam-water mixture with the temperature of 170 ℃ to 175 ℃;

s20, steam-water separation: the steam-water mixture from the water-cooled wall 401 and the barrel evaporator 60 is respectively conveyed into the steam drum 50 through the ascending pipe 405 and the ascending pipe group 602 for mixing and then is subjected to steam-water separation, low-temperature low-pressure steam and 170-175 ℃ water are respectively obtained, the 170-175 ℃ water and deoxidized water supplemented by the water pump 501 are mixed into low-temperature water, and the low-temperature water is respectively returned into the water-cooled wall 401 and the barrel evaporator 60 for circulation through the descending pipe 404 and the descending pipe group 601;

s30, primary superheating: the low-temperature low-pressure steam is conveyed into the first-stage superheater 402 through a pipeline, and the low-temperature low-pressure steam absorbs the radiant waste heat in the kiln hood 20 through the first-stage superheater 402 to obtain the superheated steam at 300-330 ℃;

s40, second-stage superheating: the superheated steam is conveyed into the secondary superheater 403 after passing through the steam collecting box 70, and the superheated steam continuously absorbs the radiant waste heat in the kiln head cover 20 through the secondary superheater 403 to obtain medium-temperature medium-pressure steam at 430 ℃ and 1.5Mpa or medium-temperature low-pressure steam at 430 ℃ and 1.2 Mpa;

s50, generating: the medium-temperature medium-pressure or medium-temperature low-pressure steam is conveyed to the steam turbine 80, and the steam turbine 80 is driven to drive the generator to generate electricity.

Further, the step of S40, the second-stage superheating further comprises:

s401, steam quality is upgraded again: the AQC steam with the temperature of 300-330 ℃ generated by the AQC waste heat boiler and the SP steam with the temperature of 285-300 ℃ generated by the SP waste heat boiler are conveyed to the steam collecting box 80, the AQC steam, the SP steam and the superheated steam are mixed into mixed superheated steam in the steam collecting box 80, the mixed superheated steam is conveyed to the secondary superheater 403, the mixed superheated steam continuously absorbs the radiant waste heat in the kiln hood 20 through the secondary superheater 403, and the medium-temperature medium-pressure steam with the temperature of 430 ℃ and the pressure of 1.5Mpa or the medium-temperature medium-pressure steam with the temperature of 430 ℃ and the pressure of 1.2Mpa is obtained.

Further, the step S10 of preheating further includes:

s101, convective heat exchange: the fan 904 is turned on to make the external cold air enter the air cooling system 90 through the air inlet 903, cool the local overheat area at the bottom of the rotary kiln 10, and the heated air continues to collect and discharge to the air outlet 902 along the gap between the rotary kiln 10 and the cylinder evaporator 60 and the gap between the cylinder evaporator 60 and the heat insulation layer 901, respectively, and the heated air transfers heat between the rotary kiln 10 shell and the cylinder evaporator 60 to form convection heat transfer.

Further, the temperature detecting device 406 is responsible for monitoring the outlet steam temperature of the secondary superheater 403 in real time, and when the steam temperature exceeds the rated temperature of the steam turbine 80, the desuperheater 701 is automatically started to cool the mixed superheated steam in the steam collecting tank 70; the desuperheater automatically shuts down when the steam temperature is below the rated temperature of the steam turbine 80. Specifically, when the temperature of the steam exceeds 430 ℃, the desuperheater 701 is automatically started to cool the mixed superheated steam in the steam collecting tank 70, and when the temperature of the steam is lower than 400 ℃, the desuperheater is automatically closed to keep the mixed superheated steam within the range of 400-430 ℃.

By adopting the rotary kiln steam quality re-upgrading system (Steam quality upgrading of system, SQUS for short) provided by the embodiment of the application, a plurality of cylinder evaporators (code TZ) are sleeved outside the rotary kiln to recover the radiation waste heat generated by the rotary kiln cylinder, a kiln head hood boiler (code FRZ) water cooling wall is arranged above a kiln head hood to absorb the radiation waste heat in the kiln head hood, and the two are respectively used for obtaining a steam-water mixture and carrying out steam-water separation after being mixed by a steam drum; the steam after steam-water separation is superheated by a primary superheater to obtain superheated steam; a primary superheater and a secondary superheater are arranged above the inside of the kiln head cover boiler, and radiation waste heat generated by the kiln head cover shell is continuously recovered; steam generated by the AQC waste heat boiler and the SP waste heat boiler is mixed with the superheated steam after primary superheating, the mixed superheated steam is subjected to steam quality re-upgrading through a secondary superheater, high-quality steam of medium-temperature medium-pressure or medium-temperature low-pressure steam is obtained and used for power generation, high-temperature radiation waste heat of a rotary kiln barrel body and a kiln hood shell which are difficult to utilize is recovered, the AQC waste heat boiler and the SP waste heat boiler which are originally only used for pure low-temperature waste heat power generation can be obtained after mixing and secondary superheating, power generation efficiency is greatly improved, and the method has strong practicability.

In the description of the present application, it should be understood that the terms "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may communicate with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims (8)

1. The utility model provides a rotary kiln steam quality upgrades system again, its characterized in that, including rotary kiln (10), kiln hood (20) and the comb cold machine (30) that communicate in proper order, kiln hood (20) top is connected with kiln hood boiler (40), be equipped with water-cooling wall (401) on the kiln hood boiler (40) casing, the output of water-cooling wall (401) is connected with steam drum (50), a plurality of barrel evaporators (60) are installed along the axial in rotary kiln (10) barrel outside, the output of barrel evaporators (60) with steam drum (50) are connected, install one-level superheater (402) and second grade superheater (403) in kiln hood boiler (40), the play vapour end of steam drum (50) with the input of one-level superheater (402) links to each other, the output of one-level superheater (402) is connected with steam header (70), the output of steam header (70) with the input of second grade superheater (403), the output of second grade superheater (403) is connected with steam turbine (80).

2. The rotary kiln steam quality re-upgrading system according to claim 1, further comprising an AQC waste heat boiler and an SP waste heat boiler, wherein steam output ends of the AQC waste heat boiler and the SP waste heat boiler are respectively connected with an input end of the steam collecting box (70).

3. The steam quality re-upgrading system for the rotary kiln according to claim 1, wherein a water inlet of the steam drum (50) is connected with a water pump (501), two water outlets of the steam drum (50) are respectively connected with input ends of the water-cooled wall (401) and the barrel evaporator (60) through a descending pipe (404) and a descending pipe group (601), and two input ends of the steam drum (50) are respectively connected with output ends of the water-cooled wall (401) and the barrel evaporator (60) through an ascending pipe (405) and an ascending pipe group (602).

4. The rotary kiln steam quality re-upgrading system according to claim 1, further comprising an air cooling system (90), wherein the air cooling system (90) comprises a barrel evaporator (60) sleeved outside the rotary kiln (10) and a heat insulation layer (901) sleeved outside the barrel evaporator (60), an air outlet (902) penetrating through the barrel evaporator (60) and the heat insulation layer (901) and an air inlet (903) are respectively formed in the bottom and the top of the air cooling system (90), and a fan (904) is arranged at the air inlet (903).

5. The steam quality re-upgrading system for a rotary kiln according to claim 4, wherein the cylindrical evaporator (60) comprises two evaporator tube sets (603) which are sleeved on the rotary kiln (10) after being buckled, and the heat insulation layer (901) comprises two heat insulation modules (905) which are sleeved on the cylindrical evaporator (60) after being buckled, and the cylindrical evaporator tube sets (603) and the heat insulation modules (905) which are positioned on the same side are connected through connecting pieces.

6. A steam quality re-upgrading system for a rotary kiln according to claim 1, wherein a temperature detection device (406) is arranged at the outlet of the secondary superheater (403), and a desuperheater (701) is arranged in the steam collecting tank (70) corresponding to the temperature detection device.

7. The rotary kiln steam quality re-upgrading system according to claim 1, wherein the bottom of the kiln head cover boiler (40) is higher than the rotary kiln port and the tertiary air duct, the kiln head cover boiler (40) is communicated with the kiln head cover (20), and no air outlet is arranged in the kiln head cover boiler (40).

8. The rotary kiln steam quality re-upgrading system according to claim 5, wherein an air cooling system (90) shell is connected to the outside of the heat insulation module (905), the air cooling system (90) shell and the heat insulation module (905) are arranged at intervals and are connected through a connecting piece, openings are formed in positions, corresponding to the air outlet (902) and the air inlet (903), of the air cooling system (90), and the air cooling system (90) shell is connected with a connecting support (906).

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