Novel soda heavy ash self-returning steam rotary furnace and application
By introducing moisture in reverse flow to reduce the partial pressure of steam and water in the furnace, the corrosion of the furnace head and the blockage of the furnace steam system in the traditional soda ash heavy ash self-return steam rotary furnace are solved. This achieves no corrosion on the inner wall of the furnace head and no blockage in the furnace steam system, thereby improving the service life of the furnace body and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-19
- Publication Date
- 2026-04-07
AI Technical Summary
The problems of easy corrosion of the furnace head and easy blockage of the furnace steam system in traditional soda ash heavy ash self-return steam rotary furnace are mainly caused by high steam-water concentration and uneven temperature.
By adopting a method of reverse flow of humid gas to reduce the partial pressure of steam and water vapor in the furnace, and combining it with the self-returning rotary kiln structure, the problem of corrosion on the inner wall of the furnace head and blockage of the furnace steam system can be solved by combining the return pipe on the outer wall of the furnace with the humid gas entering the furnace tail.
This achieves non-corrosion of the inner wall of the furnace head and non-clogging of the furnace steam system, reduces the temperature of the finished product and recovers heat, thereby improving the service life of the furnace and production efficiency.
Smart Images
Figure CN121804209A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of steam rotary kiln, in particular to a new type of soda heavy ash self-returning steam rotary kiln and application. BACKGROUND
[0002] In the production of soda heavy ash (heavy soda ash), the removal of crystallization water and free water in the monohydrate can be achieved by using a fluidized bed and a steam rotary kiln. Compared with the fluidized bed technology, the steam rotary kiln has large capacity, low energy consumption, small noise, less material crushing, and small tail gas quantity, and its outstanding advantages are recognized by the alkali industry. At the same time, compared with light ash calcination, heavy ash requires less return material, so the heavy ash furnace with self-returning material is widely used in the alkali industry.
[0003] After years of use, compared with light ash calcination furnace, the self-returning heavy ash furnace has problems such as easy corrosion of the furnace head and easy blockage of the steam system, which seriously affects normal production. Through analysis of the operation of synthetic light ash, natural light ash and heavy ash steam rotary kiln, the inventor found that the reasons for the corrosion of the furnace head and the easy blockage of the steam system are directly related to the steam concentration of the steam. As shown in the following table:
[0004] Compared with the synthetic light ash calcination furnace, the steam water vapor concentration of the heavy ash furnace is high, and the alkali outlet temperature is low. Theoretically, the steam produced by heavy ash is 100% water vapor, but because of air leakage and trace decomposition of sodium bicarbonate, the water vapor concentration is about 99%. In heavy ash production, about 150℃ of return material is fully mixed with about 75℃ of monohydrate, and the mixed material temperature is about 100℃. However, using a self-returning steam rotary kiln, wet material enters the furnace head at a low temperature, and then contacts with high-temperature return material. The two materials need a certain time and space to fully mix in the furnace head mixing section. Before that, part of the material temperature is lower than 100℃, and the temperature of some dead angle positions in the furnace head is also lower than 100℃. Under the combined influence of factors such as furnace head pressure fluctuation, even if the temperature is higher than 100℃, part of the gaseous water in the steam will condense into liquid water, which will cause the material to form a scab quickly and adhere to the metal surface, resulting in "dew point corrosion". Also because of the presence of liquid water in the steam, the steam system is prone to blockage.
[0005] Therefore, according to the above technical problems, a new type of soda heavy ash self-returning steam rotary kiln and application are designed. SUMMARY
[0006] In order to solve the above-mentioned problems, the present application provides a new type of soda heavy ash self-returning steam rotary kiln and application.
[0007] The technical scheme adopted by the present application to solve its technical problems is: a novel soda heavy ash self-returning steam rotary furnace, comprising a furnace body, the furnace body is a cylindrical rotary structure, one end of the furnace body is connected with a furnace head, and the furnace body is downwardly inclined from the furnace head to the tail of the furnace body; a feeding device is arranged at the furnace head, the feeding device is used for conveying materials into the furnace body, an outlet cover is arranged at the tail of the furnace body, the outlet cover is used for discharging finished materials, at least one return pipe is arranged on the outer wall of the furnace body, the return pipe is spiral-shaped, the inlet of the return pipe is connected with the return port at the tail of the furnace body, and the outlet of the return pipe is located at the mixing section of the furnace head side of the furnace body; a wet gas carrying inlet is arranged on the outlet cover, and the wet gas carrying inlet is used for introducing wet gas; a steam discharge port is arranged on the furnace head cover, and the steam discharge port is used for discharging wet steam after being contacted with the materials.
[0008] Working principle: due to the characteristics of sodium hydroxide, the furnace steam generated after removing free water and crystal water is almost 100% water vapor, and under normal pressure, the condensed water is separated out below 100 DEG C, and liquid water also appears above 100 DEG C in the furnace head pressure zone; the wet material and the return material are contacted and mixed in the furnace head mixing section through the rotation of the furnace head. Before the wet material is fully mixed, the temperature is below 100 DEG C, which leads to the corrosion of the furnace head mixing section at a lower temperature in the actual use of the traditional self-returning heavy ash calcining furnace, and the furnace steam system is easy to be blocked. If the steam pressure is increased, the discharge temperature is increased, and the heat carried by the return material is increased to increase the temperature of the furnace head mixing section, the purpose of not causing corrosion of the inner wall of the furnace head can also be achieved like the light ash calcining furnace. However, the heat required for heavy ash calcination is only about 35% of that for light ash calcination, and the over-high temperature leads to increased consumption. The present application adopts the method of countercurrently introducing wet gas to reduce the water vapor partial pressure of the furnace steam, and combines with the structure of the self-returning rotary furnace to solve the problems of the corrosion of the inner wall of the furnace head, the blockage of the furnace steam system and the like in the traditional self-returning heavy ash furnace from the source. At the same time, the countercurrent wet gas directly contacts the high-temperature finished product in the outlet cover, which not only reduces the temperature of the finished product, but also recovers the heat through the cooperative effect of the structure and method of the combination of the return material pipe outside the furnace body and the wet gas inlet at the tail of the furnace, so that the self-returning of the furnace body is realized, and the problems of the corrosion of the inner wall of the furnace head and the blockage of the furnace steam system are solved.
[0009] Preferably, the tail of the furnace body is provided with a steam chamber, a steam inlet shaft, a discharge spiral, and a wet gas inlet annular channel, the center of the steam chamber is the steam inlet shaft, the outer periphery of the steam inlet shaft is coaxially provided with an annular discharge spiral, and the outer periphery of the discharge spiral is coaxially provided with a wet gas inlet annular channel.
[0010] Preferably, a spiral flow guide structure is arranged in the annular channel of the wet gas, and the rotation direction of the spiral flow guide structure is opposite to the conveying rotation direction of the discharge spiral.
[0011] Preferably, the lower part of the discharge hood is provided with an air chamber, and the moisture-carrying gas inlet is opened in the air chamber; the air chamber is provided with an air distribution plate, and the moisture-carrying gas enters the discharge hood after being evenly distributed by the air distribution plate, and enters the furnace body in the opposite direction to the discharge direction of the finished material; a spare air inlet is provided at the upper part of the discharge hood.
[0012] Preferably, an ash-blocking ring is provided on the inner wall of the furnace tail, located on the furnace tail side of the return material port; a return material valve is provided at the return material port, the return material valve is used to adjust the return material amount, and a material discharge port is also provided at the furnace tail, and multiple return material ports are provided.
[0013] Preferably, at least one set of heat exchange tubes is arranged circumferentially inside the furnace body, the heat exchange tubes extend from the tail of the furnace to the head of the furnace, and the ends of the heat exchange tubes are located outside the mixing section; several sets of lifting plates are evenly arranged on the inner wall of the furnace body in the mixing section, and the several sets of lifting plates are arranged at a certain interval.
[0014] Preferably, the furnace body is provided with a front rolling ring and a rear rolling ring. A front support roller device is provided below the front rolling ring, and a rear support roller device is provided below the rear rolling ring. The furnace body is supported on the front and rear support roller devices by the front and rear rolling rings. A stop roller device is provided at the rear support roller device. The furnace body is provided with a large gear ring, and a transmission device is connected to the corresponding position of the large gear ring. The transmission device includes a small gear ring, and the pinion of the transmission device meshes with the large gear ring. The pinion is located on the side of the rear rolling ring closer to the furnace head.
[0015] Preferably, the steam inlet shaft extends towards the tail of the furnace and passes through the discharge hood, and the steam inlet shaft is connected to the external steam inlet box through a multi-stage sealing device; the steam inlet box is provided with a steam inlet and a condensate outlet.
[0016] Preferably, the moisture carrier gas includes air drawn from the site environment and extracted from a location far from the boiler exhaust outlet.
[0017] The application of a novel steam rotary kiln for self-returning soda ash includes the drying of ammonium chloride containing 2% to 10% free water.
[0018] The advantages of this invention are: The present invention achieves a synergistic effect through the combination of the furnace outer wall return pipe and the furnace tail inlet moisture-carrying gas structure and method, realizing the return of material to the furnace body while solving the problems of furnace head inner wall corrosion and furnace steam system blockage. The furnace tail inlet moisture-carrying gas reduces the partial pressure of water vapor in the furnace steam, solving the "dew point corrosion" that occurs at the furnace head due to low temperature and pressure fluctuations. The low-temperature moisture-carrying gas entering from the furnace tail directly contacts the finished product, both reducing the finished product temperature and recovering heat. The moisture-carrying gas, in direct counter-current contact with the finished product, replaces the water vapor entrained in the finished product, preventing water vapor condensation that would occur during subsequent temperature reductions. The addition of moisture-carrying gas reduces the water vapor concentration in the furnace steam, ensuring that the furnace steam system will not experience blockage below 100°C.
[0019] This invention is applicable to the calcination of heavy ash produced by the traditional solid-liquid phase method, as well as the calcination of heavy ash (containing a small amount of sesquialkali) produced directly from natural alkali.
[0020] For natural alkali light ash calcining furnaces, the steam pressure can be reduced from the current 3.2 MPa to 2.0~2.5 MPa after adopting this invention. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the furnace tail structure of the present invention; Figure 3 This is a schematic diagram of the structure of the discharge hood of the present invention; Figure 4 This is a schematic diagram of the structure of the discharge hood of the present invention; Figure 5 This is a schematic diagram of the structure of a wind chamber and air distribution plate according to the present invention; Figure 6 This is a schematic diagram of another air chamber arrangement for a novel steam rotary furnace for self-returning soda ash and heavy ash, according to the present invention.
[0023] In the diagram: 1. Feeding device; 2. Furnace head; 3. Front wheel assembly; 4. Furnace body; 5. Return pipe; 6. Transmission device; 7. Rear wheel assembly; 8. Steam heat exchanger pipe; 9. Ash baffle ring; 10. Steam inlet shaft; 11. Steam chamber; 12. Moist gas inlet channel; 13. Discharge screw; 14. Discharge hood; 1401. Discharge hood shell; 15. Steam inlet box; 16. Return valve; 17. Air chamber; 1701. Air distribution plate; 1702. Air chamber upper plate; 1703. Air chamber side plate; 1704. Air distribution plate seat; 18. Discharge valve; a. Wet material inlet; b. Furnace steam outlet; c. Return port; d. Discharge port; e. Air inlet; f. Backup air inlet; g. Steam inlet; h. Air distribution hole of air distribution plate; j. Drain port. Detailed Implementation
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] Please see Figures 1-6 As shown, the present invention uses a furnace body 4 arranged at an angle on front and rear supports installed at an angle along the axis (front higher than rear), and the transmission device 6 also maintains the same angle of inclination. The high end of the furnace body 4 is the furnace head 2, which is connected to the feeding device 1, and the furnace head 2 has a furnace steam outlet; the low end of the furnace body 4 is the furnace tail, which is equipped with a finished product discharge hood 14, and the discharge hood 14 has a moisture-carrying inlet; further back from the discharge hood 14, there is a steam inlet box 15, with a steam inlet g above the steam inlet box 15 and a condensate outlet below.
[0026] Both the front tow wheel device 3 and the rear tow wheel device 7 include two support rollers, with the front and rear rollers respectively mounted between the two tow wheels, as detailed below. Figure 1 As shown, the rear support roller is provided with guide wheels on the front and rear sides to control the upward and downward movement of the rotary kiln during operation.
[0027] The feeding device 1 is connected to the furnace head 2. The furnace head 2 is dynamically and statically connected to the rotating furnace body 4 through a mature sealing device. There is a steam outlet at the top of the furnace head 2.
[0028] The outer wall of the furnace body 4 is spirally wound with a return pipe 5; the tail section of the furnace body 4 has a return outlet, which is connected to the return pipe 5 on the outer wall of the furnace body 4 via a return valve 16; the furnace head 2 has a return inlet on the feeding side of the mixing section of the furnace body 4, which is connected to the return pipe 5 on the outer wall of the furnace body 4.
[0029] The discharge hood 14 is located after the tail steam chamber 11. Material is fed through the discharge screw 13, passing through the center of the steam chamber 11, and then to the discharge hood 14, exiting from the discharge port d at the bottom of the discharge hood 14. This discharge port d is connected to a conventionally available airlock star-shaped discharge valve. A moisture-carrying air chamber 17 is located at the bottom of the discharge hood 14, with a moisture-carrying inlet. The discharge hood 14 achieves dynamic and static connection with the rotating components through a mature sealing device. The air chamber 17 specifically includes: an air distribution plate 1701; an upper air chamber plate 1702; a side air chamber plate 1703; and an air distribution plate seat 1704. The air distribution plate 1701, upper air chamber plate 1702, side air chamber plate 1703, and air distribution plate seat 1704 surround to form an air chamber 17. In this invention, the air distribution plate 1701 adopts the following... Figure 3 The installation method shown is to place it above the air distribution plate base 1704. Meanwhile, in the specific implementation process, the air distribution plate 1701 is not only as... Figure 3 In the specific connection process, the discharge hood 14 has a large end that uses mature dynamic and static sealing technology to connect with the outer wall of the rotating moisture-carrying air inlet channel 12; and a small end that uses mature dynamic and static sealing technology to connect with the outer wall of the rotating steam inlet shaft 10.
[0030] The steam inlet box 15 is located at the tail of the steam inlet shaft 10. Steam enters the steam inlet shaft 10 through the steam inlet box 15, and condensate is discharged through the steam inlet box 15. The steam inlet shaft 10 is connected to the steam chamber 11. The stationary steam inlet box 15 and the rotating steam inlet shaft 10 are integrated into one unit using mature sealing technology. The heat exchange tube assembly is fixed to the steam chamber 11 and arranged concentrically around the axis of the rotary kiln. The heating tubes extend from the tail of the furnace to the head of the furnace 2, but do not enter the mixing section of the head of the furnace 2.
[0031] The steam inlet shaft 10, the discharge screw 13 channel, and the moisture-carrying gas inlet annular channel all pass through the steam chamber 11. The steam inlet shaft 10 is located at the center of the steam chamber 11. The discharge screw 13 channel is located outside the steam inlet shaft 10. The moisture-carrying gas inlet annular channel is located outside the discharge channel. The annular discharge screw 13 is located outside the steam inlet shaft 10. The annular moisture-carrying gas channel is located outside the shell of the discharge screw 13. The moisture-carrying gas channel is equipped with a screw, and its rotation direction is opposite to that of the discharge screw 13. In a specific embodiment, the screw can be single-headed or multi-headed.
[0032] The transmission device 6 is located in front of the rear support roller ring. A large gear ring is provided on the outer side of the furnace body 4. The transmission device 6 includes a small gear that meshes with the large gear ring; a reducer connected to the small gear; and the reducer is connected to a variable frequency motor.
[0033] The invention provides a novel operating method for a steam rotary kiln for self-returning soda ash, comprising the following processes: Moisture-laden gas enters the air chamber 17 from the lower air inlet e of the discharge hood 14, passes through the air distribution plate 1701, and then enters the discharge hood 14. It comes into countercurrent contact with the high-temperature material from the discharge screw 13, cooling the material while replacing the water vapor entrained within it. The moisture-laden gas, heated by the recovered heat, enters the tail of the furnace body 4 through the moisture-laden gas inlet channel 12, flowing from tail to head, passing through the entire furnace body 4, carrying water vapor, and then exiting from the furnace steam outlet of the furnace head 2. The moisture-laden gas inlet channel 12 is designed with a spiral that rotates in the opposite direction to the discharge screw 13, facilitating the smooth entry of moisture-laden gas into the furnace while hindering the exit of material from the furnace through this channel. The upper part of the discharge hood 14 has a spare air inlet e, which is used when the air distribution plate 1701 is blocked. The finished product passes through the discharge spiral 13 in the center of the steam chamber 11, passes through the steam chamber 11, and exits from the discharge hood 14. The monohydrate alkaline wet material containing free water enters the mixing section inside the furnace body 4 from the feeding device 1 at the wet material inlet a of the furnace head 2. The return screw also sends the high-temperature finished product from the furnace tail into the mixing section. The finished product and the wet material are mixed in the mixing section. The mixed material passes through the heat exchange tube in the furnace and indirectly exchanges heat with the steam, removing free water and crystal water. It first reaches the return material outlet d at the furnace tail. The return material outlet d is located before the ash baffle ring 9 at the tail of the furnace. The return material outlet c of the furnace body 4 is equipped with a return material valve 16 to regulate the amount of return material entering the return material pipe 5; the material that has passed over the ash baffle ring 9 enters the discharge screw 13 in the center of the steam chamber 11, passes through the steam chamber 11, and exits from the discharge hood 14; The furnace body 4 in front of the steam chamber 11 at the tail end of the furnace has a drain port j, which is used to drain the material in the furnace when the shutdown time is long.
[0034] This embodiment provides the following application example: Application Example 1: A traditional heavy ash self-returning calciner, Ø3600*25000, with a production capacity of about 1500t / d, developed severe corrosion at the furnace head 2 and frequent blockages in the furnace steam box in less than a year of use.
[0035] Application Example 2: The traditional heavy ash self-efficacy calcining furnace, Ø3200*20000, has a production capacity of approximately 850t / d. In less than a year of use, corrosion appeared on furnace head 2, requiring multiple repairs; the furnace steam box was cleaned multiple times per shift.
[0036] This invention provides a novel steam rotary kiln and method for self-returning heavy ash from soda ash. The steam rotary kiln for self-returning heavy ash is a calcining furnace with a diameter of not less than 3600 mm and a daily output of not less than 1500 t / d. The structure and method employing a combination of the return pipe 5 on the outer wall of the furnace body 4 and the low-temperature humidified gas inlet at the furnace tail ensures both the amount and temperature of self-returned material and solves the corrosion problem of the inner wall of the furnace body 4, while also reducing the finished product discharge temperature. Under operating conditions, the furnace temperature is as low as 80℃, and no liquid water appears. Similar to the self-returning light ash calcining furnace, no corrosion occurs inside the furnace head 2. The steam box only needs to be inspected during regular equipment maintenance. The cold humidified gas directly contacts the high-temperature finished product (approximately 150℃) within the discharge hood 14, reducing the temperature to approximately 90~110℃ (varying with winter and summer ambient temperatures). From the above, it can be concluded that the steam output per ton of product is comparable to that of natural soda ash light ash.
[0037] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A novel steam rotary kiln for self-returning soda ash, characterized in that: The furnace includes a furnace body (4), which is a cylindrical rotary structure. A furnace head (2) is connected to one end of the furnace body (4). The furnace body (4) is inclined downwards from the furnace head (2) towards the tail end of the furnace body (4). A feeding device (1) is provided at the furnace head (2) to convey materials into the furnace body (4). A discharge hood (14) is connected to the tail end of the furnace body (4) to discharge finished materials. At least one return pipe (5) is provided on the outer wall of the furnace body (4). The return pipe (5) is spiral. The inlet of the return pipe (5) is connected to the return port (c) at the tail of the furnace body (4). The outlet of the return pipe (5) is located in the mixing section of the furnace body (4) on the side of the furnace head (2). A moisture-carrying gas inlet is provided on the discharge hood (14) for introducing moisture-carrying gas. A furnace steam outlet (b) is provided on the furnace head (2) hood for discharging the moisture-laden steam after contact with the material.
2. The novel soda ash heavy ash self-return steam rotary furnace according to claim 1, characterized in that: The tail of the furnace body (4) is provided with a steam chamber (11), a steam inlet shaft (10), a discharge screw (13), and a moisture-carrying gas inlet annular channel. The center of the steam chamber (11) is the steam inlet shaft (10). The outer periphery of the steam inlet shaft (10) is provided with an annular discharge screw (13). The outer periphery of the discharge screw (13) is provided with an annular moisture-carrying gas inlet channel.
3. A novel steam rotary kiln for self-returning soda ash as described in claim 2, characterized in that: The annular channel carrying moisture is provided with a spiral guide structure, and the spiral direction of the spiral guide structure is opposite to the conveying direction of the discharge spiral (13).
4. The novel soda ash heavy ash self-return steam rotary furnace according to claim 1, characterized in that: The lower part of the discharge hood (14) is provided with an air chamber (17), and the moisture-carrying gas inlet is opened in the air chamber (17); the air chamber (17) is provided with an air distribution plate (1701), and the moisture-carrying gas enters the discharge hood (14) after being evenly distributed by the air distribution plate (1701), and enters the furnace body (4) in the opposite direction to the discharge direction of the finished material. The upper part of the discharge hood (14) is provided with a spare air inlet (f).
5. A novel steam rotary kiln for self-returning soda ash as described in claim 1, characterized in that: On the inner wall of the furnace tail of the furnace body (4), a baffle ring (9) is provided on the side of the furnace tail of the return port (c); a return valve (16) is provided at the return port (c), the return valve (16) is used to adjust the amount of return material, and a material discharge port (j) is also provided at the furnace tail, and multiple return ports (c) are provided.
6. A novel steam rotary kiln for self-returning soda ash heavy ash as described in claim 1 or 2, characterized in that: The furnace body (4) has at least one set of heat exchange tubes arranged circumferentially inside, the heat exchange tubes extending from the tail of the furnace to the head of the furnace (2), and the end of the heat exchange tubes located outside the mixing section; a number of sets of lifting plates are evenly arranged on the inner wall of the furnace body (4) in the mixing section, and the number of sets of lifting plates are arranged at a certain interval.
7. A novel steam rotary kiln for self-returning soda ash as described in claim 1, characterized in that: The furnace body (4) is provided with a front rolling ring and a rear rolling ring. A front drag wheel device (3) is provided below the front rolling ring, and a rear drag wheel device (7) is provided below the rear rolling ring. The furnace body (4) is supported on the front and rear drag wheel devices by the front and rear rolling rings. A stop wheel device is provided at the rear drag wheel device. A large gear ring is provided on the furnace body (4). A transmission device (6) is connected to the corresponding position of the large gear ring. The transmission device (6) includes a small gear ring. The small gear of the transmission device (6) meshes with the large gear ring. The small gear is located on the side of the rear rolling ring near the furnace head (2).
8. A novel steam rotary kiln for self-returning soda ash as described in claim 2, characterized in that: The steam inlet shaft (10) extends toward the tail of the furnace and passes through the discharge hood (14). The steam inlet shaft (10) is connected to the external steam inlet box (15) through a multi-stage sealing device. The steam inlet box (15) is provided with a steam inlet (g) and a condensate outlet.
9. A novel steam rotary kiln for self-returning soda ash as described in claim 1, characterized in that: The moisture-carrying gas includes air drawn from the field environment and extracted from a location far from the boiler exhaust outlet (b).
10. An application of the novel soda ash self-return steam rotary kiln as described in any one of claims 1 to 9, characterized in that: This includes the drying of ammonium chloride containing 2% to 10% free water.