Black liquor spraying device and alkali recovery furnace
By introducing a shrinking structure into the black liquid injection device, the corrosion problems caused by uneven temperature of the spray gun outlet pipe and cavitation are solved, extending the service life and improving the durability of the equipment.
Patent Information
- Application Number
- CN202420881835.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-25
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-04-25
AI Technical Summary
The uneven temperature and cavitation of the gun outlet pipes in the existing alkali recovery furnaces cause corrosion of the gun barrel wall, shortening the service life.
A black liquid injection device is designed, including a direct diversion tube, a jet elbow and a built-in shrinkage structure. The liquid jet port of the reduced diameter structure is far away from one end of the direct diversion tube, and the inner diameter is smaller than the inner diameter of the jet elbow to avoid spraying. The elbow is dissatisfied with the tube, and the black liquid is sprayed out as soon as possible through the small inner diameter spray port to reduce cavitation.
It effectively reduces corrosion of the pipe wall of the injection device, extends the service life of the black liquid injection device, and prevents corrosion caused by high-temperature flame burning by cooling and cooling, reducing cavitation problems.
Smart Images
Figure CN222226931U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of alkali recovery equipment, in particular to a black liquor injection device and an alkali recovery furnace. Background Art
[0002] Black liquor refers to the washing liquid of pulp after washing and cooking in the process of pulping by kraft process or caustic soda process. The alkali recovery section in the field of pulping and papermaking industry can not only recover the heat energy of black liquor, but also recover the alkali in black liquor for cooking, while eliminating the pollution of black liquor. At present, jet alkali recovery furnace is generally used for alkali recovery. Jet alkali recovery furnace is an alkali recovery furnace that uses a spray gun to spray black liquor into droplets of a certain size, so that the black liquor evaporates and dries in the space or furnace wall.
[0003] At present, the spray gun in the alkali recovery furnace is in a high-temperature environment. When the black liquor passes through the elbow of the spray gun, the direction of the black liquor flow changes, and some inner walls are exposed to less black liquor, resulting in uneven temperature of the spray gun outlet pipe. The softening of the high-temperature area of the outer wall and the flushing of the black liquid on the inner wall cause two-way corrosion of the spray gun. Utility Model Content
[0004] The utility model aims to provide a black liquor injection device and an alkali recovery furnace, which can reduce the corrosion of the pipe wall of the black liquor injection device and thus prolong the service life of the black liquor injection device.
[0005] In the first aspect, the utility model provides a black liquid injection device, comprising: a guide straight pipe, an injection elbow and a reducing structure arranged in the injection elbow, the guide straight pipe has a first end and a second end, the injection elbow is connected to the first end of the guide straight pipe, the reducing structure is located in the injection elbow at one end away from the guide straight pipe, the reducing structure has a liquid injection port, and the inner diameter of the end of the liquid injection port away from the guide straight pipe is smaller than the inner diameter of the injection elbow.
[0006] Compared with the prior art, the black liquor injection device provided by the utility model comprises a flow guiding straight pipe, a spray elbow and a diameter reducing structure arranged in the spray elbow. The flow guiding straight pipe has a first end and a second end, and the spray elbow is connected to the first end of the flow guiding straight pipe, and the black liquor can enter the spray elbow through the flow guiding straight pipe. At the same time, since the diameter reducing structure is located at an end of the spray elbow away from the flow guiding straight pipe, that is, the outer end of the spray elbow, the diameter reducing structure has a liquid injection port. At this time, the liquid injection port of the diameter reducing structure can be used to spray out the black liquor from the flow guiding straight pipe. In addition, since the inner diameter of the end of the liquid injection port of the reduced-diameter structure away from the guide straight pipe is smaller than the inner diameter of the injection elbow, when the black liquor reaches the injection elbow, the liquid injection port with a small inner diameter can fill the injection elbow with the black liquor coming from the guide straight pipe with a large inner diameter, thereby avoiding the phenomenon that the black liquor does not fill the tube in the injection elbow. The relatively low-temperature black liquor flowing through the injection elbow can fully contact the inner wall of the injection elbow, thereby cooling the injection elbow, avoiding the phenomenon that the high-temperature flame in the alkali recovery furnace directly burns the injection elbow and causes corrosion and burning through of the injection elbow, thereby extending the service life of the black liquor injection device.
[0007] On this basis, since the size of the liquid injection port is smaller than the size of the injection elbow, the black liquor can be sprayed out as quickly as possible and boil and vaporize as far away from the injection elbow as possible. Therefore, the cavitation generated on the surface of the black liquor injection device can be reduced and the service life of the black liquor injection device can be extended.
[0008] It can be seen from the above that the black liquor injection device of the embodiment of the utility model can reduce the corrosion of the pipe wall of the black liquor injection device, thereby extending the service life of the black liquor injection device.
[0009] In a second aspect, the utility model further provides an alkali recovery furnace, comprising the black liquor injection device described in the first aspect of the embodiment of the utility model.
[0010] Compared with the prior art, the beneficial effects of the preparation method of the alkali recovery furnace provided by the utility model are the same as the beneficial effects of the black liquor injection device of the first aspect, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0012] Figure 1 It is a schematic structural diagram of a black liquor injection device according to an exemplary embodiment of the present utility model.
[0013] Reference numerals:
[0014] 100-direction straight pipe, a-first end, b-second end, 200-injection elbow, 300-reducing structure, 310-liquid injection port, 400-baffle. DETAILED DESCRIPTION
[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0016] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0017] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.
[0018] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.
[0019] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0020] Black liquor refers to the washing liquid of pulp after washing and cooking in the process of pulping by the kraft method or caustic soda method. Black liquor contains about 30% to 35% of inorganic matter. The main components of inorganic matter are sodium hydroxide, sodium carbonate, sodium sulfide, sodium sulfate and other sodium salts combined with organic matter, and 65% to 70% of organic matter. The main components of organic matter are lignin, resin, starch and low molecular weight compounds. It is called black liquor because of its dark brown color. The alkali recovery section in the field of pulp and paper industry can not only recover the heat energy of black liquor, provide steam required for production process through the combustion of organic matter in black liquor, but also recover alkali in black liquor for cooking, and eliminate the pollution of black liquor at the same time. At present, jet alkali recovery furnace is generally used for alkali recovery. Jet alkali recovery furnace is an alkali recovery furnace that uses a spray gun to spray black liquor into droplets of a certain size, so that the black liquor evaporates and dries in the space or furnace wall.
[0021] After evaporation and extraction, the dilute black liquor becomes concentrated black liquor. After being heated directly or indirectly by steam, the concentrated black liquor is sprayed into the furnace through a black liquor spray gun. There are many types of black liquor spray guns. The most commonly used one is the reflective type, also known as the baffle type. The spray gun is a device that sprays the black liquor into the furnace. After observation and analysis, it was found that the black liquor spray gun currently used changes the direction of the fluid when the black liquor passes through the elbow of the spray gun mouth, and the amount of black liquor contacted by some inner walls is small. The temperature of the pipe at the outlet of the spray gun is uneven, and the high-temperature area of the outer wall softens and the black liquid flushes the inner wall, causing two-way corrosion. However, the function of the spray gun is to spray the black liquor into the alkali furnace for combustion, and the working conditions of the external high-temperature environment cannot be changed.
[0022] The spray guns currently in use are standard finished product spray guns purchased directly from the market. The inner diameter of the spray gun tube is a fixed diameter and the flow rate cannot be adjusted. Under actual working conditions, when black liquor is transported to the spray gun tube through the metal hose, the spray gun is not full due to the equal tube diameter. The spray gun is directly inserted into the alkali furnace, and the internal working condition of the alkali furnace is an ultra-high temperature environment with a negative pressure of about -50kPa. The parts of the spray gun filled with liquid have black liquor flowing through them (the temperature of the black liquor is about 142°C, but it is also far lower than the temperature of the flame burning in the alkali furnace). The flow of black liquor plays a role of a coolant to cool the spray gun, while the places without black liquid (generally above the spray gun near the outlet when the tube is not full) appear hollow. This part will be directly burned by the high-temperature flame in the alkali furnace and eventually burn through and become scrapped. On the other hand, when the black liquor is sprayed from the spray gun into the alkali furnace, the boiling point of the black liquor at the outlet decreases due to the change in pressure (positive pressure becomes negative pressure), causing the black liquor to boil. The boiling of the black liquor will produce bubbles, and the bursting of the bubbles will cause cavitation on the metal surface of the spray gun. The service life of the black liquor spray gun is greatly reduced under the two environments of high temperature burning and alkaline cavitation.
[0023] In view of the above problems, the embodiment of the utility model provides a black liquor injection device and an alkali recovery furnace to solve the problems of uneven temperature of the spray gun outlet pipe and corrosion of the spray gun pipe wall caused by bubbles generated at the spray gun outlet in the prior art. The corrosion of the pipe wall of the black liquor injection device can be reduced, thereby extending the service life of the black liquor injection device. It should be understood that the black liquor injection device can be a black liquor spray gun.
[0024] Figure 1 The schematic diagram of the structure of the black liquor injection device of the exemplary embodiment of the utility model is shown. Figure 1 As shown, the black liquor injection device provided by the exemplary embodiment of the utility model includes a guide straight pipe 100, an injection elbow 200 and a reducing structure 300 arranged in the injection elbow 200, the guide straight pipe 100 has a first end a and a second end b, the injection elbow 200 is connected to the first end a of the guide straight pipe 100, the reducing structure 300 is located in the injection elbow 200 at one end away from the guide straight pipe 100, the reducing structure 300 has a liquid injection port 310, and the inner diameter of the end of the liquid injection port 310 away from the guide straight pipe 100 is smaller than the inner diameter of the injection elbow 200.
[0025] It is understandable that the second end b of the straight flow guide pipe 100 can be connected to the black liquor pipeline to transport the black liquor from the black liquor pipeline to the black liquor injection device of the present invention. The reduced diameter structure 300 can be a cylinder of equal diameter when viewed from the outer surface.
[0026] In specific implementation, first, the black liquor produced in the papermaking process can be transported from the second end b to the flow guiding straight pipe 100 by using the black liquor pipeline. Since the jet elbow 200 is connected to the first end a of the flow guiding straight pipe 100, the black liquor can enter the jet elbow 200 through the flow guiding straight pipe 100. At this time, since the diameter reduction structure 300 is located at one end of the jet elbow 200 away from the flow guiding straight pipe 100, that is, the outer end of the jet elbow 200, the diameter reduction structure 300 has a liquid injection port. Therefore, the liquid injection port 310 of the diameter reduction structure 300 can be used to spray out the black liquor from the flow guiding straight pipe 100. Then, since the inner diameter of the liquid injection port 310 of the reducing structure 300 away from the end of the guide straight pipe 100 is smaller than the inner diameter of the injection elbow 200, when the black liquor reaches the injection elbow 200, the liquid injection port 310 with a small inner diameter can make the black liquor from the guide straight pipe 100 with a large inner diameter fill the injection elbow 200, thereby avoiding the phenomenon that the black liquor does not fill the injection elbow 200. When the relatively low temperature black liquor flows through the injection elbow 200, it can fully contact the inner wall of the injection elbow 200, thereby playing a role in cooling the injection elbow 200, avoiding the phenomenon that the high temperature flame in the alkali recovery furnace directly burns the injection elbow 200 and causes the injection elbow 200 to corrode and burn through, thereby extending the service life of the black liquor injection device.
[0027] On this basis, since the size of the liquid injection port 310 is smaller than that of the injection elbow 200, the black liquor can be sprayed out as quickly as possible and boil and vaporize as far away from the injection elbow 200 as possible. Therefore, the cavitation generated on the surface of the black liquor injection device can be reduced, thereby extending the service life of the black liquor injection device.
[0028] In an achievable manner, the inner diameter of the liquid injection port 310 of the embodiment of the utility model gradually increases along the direction in which the injection elbow extends to the flow guide straight pipe 100. It should be understood that the direction in which the injection elbow extends to the flow guide straight pipe 100 may be the direction A in the figure. That is, along the direction A, the inner diameter of the liquid injection port 310 gradually increases.
[0029] In specific implementation, when the black liquor from the guide straight pipe 100 enters the injection elbow 200, since the inner diameter of the liquid injection port 310 gradually increases along the direction in which the injection elbow extends toward the guide straight pipe 100, the black liquor will first enter the position of the liquid injection port 310 with a larger inner diameter, and then gradually flow to the position of the liquid injection port 310 with a smaller inner diameter before being ejected. In this process, on the one hand, the black liquor with a relatively low temperature can fully contact the inner wall of the injection elbow 200 when flowing through the injection elbow 200, avoiding the phenomenon that the black liquor does not fill the pipe in the injection elbow 200, thereby playing a role in cooling the injection elbow 200, avoiding the phenomenon that the high-temperature flame in the alkali recovery furnace directly burns the injection elbow 200, causing the injection elbow 200 to corrode and burn through, and extending the service life of the black liquor injection device. On the other hand, minimizing the pipe diameter at the outlet can pressurize the black liquid to a certain extent, spraying it out as quickly as possible and keeping it away from the injection elbow. Boiling and vaporizing it as far away from the muzzle as possible can reduce cavitation on the metal surface of the spray gun, thereby extending the service life of the spray gun.
[0030] In an optional manner, the shape of the liquid injection port 310 of the embodiment of the utility model can be a cone. It should be understood that the liquid injection port 310 is tapered within a certain thickness along the axial direction of the diameter reduction structure 300, the inner diameter gradually decreases, and the cross section of the liquid injection port 310 is an isosceles trapezoid.
[0031] For example, the axial length of the diameter-reducing structure 300 of the embodiment of the utility model is smaller than the axial length of the injection elbow 200. The axial length of the diameter-reducing structure 300 is set to be smaller than the axial length of the injection elbow 200. Since the inner diameter of the diameter-reducing structure 300 is smaller than the inner diameter of the injection elbow 200, the instantaneous impact force of the black liquor coming from the diversion straight pipe 100 allows the black liquor to fill the inner wall of the injection elbow 200 when it just reaches the injection elbow 200, and then enter the diameter-reducing structure 300. Therefore, it is possible to avoid the instantaneous impact force of the black liquor coming from the diversion straight pipe 100 being too large to cause damage or wear to the diameter-reducing structure 300, thereby reducing the impact of the impact force on the diameter-reducing structure.
[0032] In one example, the diameter of the injection elbow 200 of the embodiment of the utility model is less than or equal to the diameter of the diversion straight pipe 100. Setting the diameter of the injection elbow 200 to be less than or equal to the diameter of the diversion straight pipe 100 can ensure that the black liquor from the diversion straight pipe 100 fills the inner wall of the injection elbow 200, avoiding the problem of uneven temperature of the spray gun outlet pipe due to the small amount of black liquor contacted by the inner wall, and reducing the corrosion of the injection elbow 200.
[0033] In another example, in the embodiment of the utility model, if the diameter of the injection elbow 200 is smaller than the diameter of the flow guiding straight pipe 100, the black liquor injection device further comprises an elbow adapter, and the flow guiding straight pipe 100 and the injection elbow 200 are fixedly connected through the elbow adapter, and the elbow adapter is respectively connected with the flow guiding straight pipe 100 and the injection elbow 200. It should be understood that the elbow adapter can be an adapter having one end with the same inner diameter as the flow guiding straight pipe 100 and the other end with the same inner diameter as the injection elbow 200. Using the elbow adapter to connect the flow guiding straight pipe 100 and the injection elbow 200 can achieve conduction when the inner diameters of the flow guiding straight pipe 100 and the injection elbow 200 are different.
[0034] For example, the diameter reduction structure 300 of the embodiment of the utility model is detachably connected to the injection elbow 200. It should be understood that the detachable connection method here can be a clamping connection, a threaded connection or other detachable connection methods, which can be selected according to actual needs and are not limited here. Therefore, when the diameter reduction structure 300 is worn or damaged, the black liquor injection device can be reused by simply removing the diameter reduction structure 300 and replacing it, which greatly improves the economic benefits of using spare parts.
[0035] In an achievable manner, the diameter of the second end b of the flow guiding straight pipe 100 of the embodiment of the utility model is greater than or equal to the diameter of the first end a of the flow guiding straight pipe 100. It should be understood that if the diameter of the second end b of the flow guiding straight pipe 100 is greater than the diameter of the first end a of the flow guiding straight pipe 100, the diameter of the flow guiding straight pipe 100 gradually decreases along the direction from the second end b to the first end a. This design can ensure that the black liquor from the second end b of the flow guiding straight pipe 100 can fill the inner wall of the flow guiding straight pipe 100 during the process of flowing to the first end a of the flow guiding straight pipe 100, thereby avoiding the problem of corrosion of the flow guiding straight pipe 100 caused by the small amount of black liquor contacted by the inner wall of the flow guiding straight pipe 100.
[0036] Exemplarily, the black liquor injection device of the embodiment of the present invention further includes a baffle plate 400 disposed at the bottom of the injection elbow 200, and the baffle plate 400 can make the injection direction of the black liquor be the target direction.
[0037] The embodiment of the present invention further provides an alkali recovery furnace, which comprises the black liquor injection device of the embodiment of the utility model.
[0038] As can be seen from the above, in the black liquor injection device provided by the embodiment of the utility model, the black liquor can enter the injection elbow through the guide straight pipe, and the black liquor from the guide straight pipe can be sprayed out by using the liquid injection port of the reduced diameter structure. In addition, since the inner diameter of the end of the liquid injection port of the reduced diameter structure away from the guide straight pipe is smaller than the inner diameter of the injection elbow, when the black liquor reaches the injection elbow, the liquid injection port with a small inner diameter can make the black liquor from the guide straight pipe with a large inner diameter fill the injection elbow, avoiding the phenomenon that the black liquor does not fill the pipe in the injection elbow. The relatively low temperature black liquor flowing through the injection elbow can fully contact with the inner wall of the injection elbow, thereby playing a role in cooling the injection elbow, avoiding the phenomenon that the high temperature flame in the alkali recovery furnace directly burns the injection elbow and causes the injection elbow to corrode and burn through, thereby extending the service life of the black liquor injection device.
[0039] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.
[0040] The above is only a specific implementation of the utility model. Obviously, various modifications and combinations can be made to it without departing from the spirit and scope of the utility model. Accordingly, this specification and the drawings are only exemplary illustrations of the utility model defined by the attached claims, and are deemed to have covered any and all modifications, changes, combinations or equivalents within the scope of the utility model. Obviously, those skilled in the art can make various changes and modifications to the utility model without departing from the spirit and scope of the utility model. In this way, if these modifications and variations of the utility model fall within the scope of the claims of the utility model and their equivalents, the utility model is intended to include these changes and variations. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be covered within the scope of protection of the utility model. Therefore, the scope of protection of the utility model shall be based on the scope of protection of the claims.
Claims
1. A black liquor injection device, characterized in that: include: A flow guiding straight pipe, an injection elbow and a reducing structure arranged in the injection elbow, the flow guiding straight pipe has a first end and a second end, the injection elbow is connected to the first end of the flow guiding straight pipe, the reducing structure is located in the injection elbow at one end away from the flow guiding straight pipe, the reducing structure has a liquid injection port, and the inner diameter of the end of the liquid injection port away from the flow guiding straight pipe is smaller than the inner diameter of the injection elbow.
2. The black liquor injection device according to claim 1, characterized in that: The inner diameter of the liquid injection port gradually increases along the direction in which the injection elbow extends toward the flow guide straight pipe.
3. The black liquor injection device according to claim 2, characterized in that: The liquid injection port has a conical shape.
4. The black liquor injection device according to claim 2, characterized in that: The axial length of the reduced diameter structure is smaller than the axial length of the injection elbow.
5. The black liquor injection device according to claim 1, characterized in that: The diameter of the injection elbow is smaller than or equal to the diameter of the flow guiding straight pipe.
6. The black liquor injection device according to claim 5, characterized in that: If the diameter of the injection elbow is smaller than the diameter of the guide straight pipe, the black liquor injection device further comprises an elbow adapter, the guide straight pipe and the injection elbow are fixedly connected via the elbow adapter, and the elbow adapter is respectively connected to the guide straight pipe and the injection elbow.
7. The black liquor injection device according to any one of claims 1 to 6, characterized in that: The diameter reduction structure is detachably connected to the injection elbow.
8. The black liquor injection device according to any one of claims 1 to 6, characterized in that: The diameter of the second end of the straight flow guiding pipe is greater than or equal to the diameter of the first end of the straight flow guiding pipe.
9. The black liquor injection device according to claim 8, characterized in that: If the diameter of the second end of the straight flow guiding pipe is greater than the diameter of the first end of the straight flow guiding pipe, the diameter of the straight flow guiding pipe gradually decreases along the direction from the second end to the first end.
10. An alkali recovery furnace, characterized in that: The alkali recovery furnace comprises the black liquor injection device according to any one of claims 1 to 9.