A method for processing a coke oven gas pre-desulfurization nozzle

Abstract

The application discloses a processing method of a nozzle for coke oven gas pre-desulfurization, and the process comprises the following steps: wax mold precision casting of a flange and a spherical head, rough turning of an inner circle, rough turning of an outer circle of a distribution plate, turning of an end surface, drilling of straight holes, milling bed drilling of inclined holes, fine turning of the outer circle, and assembling of the distribution plate and the spherical head. The method has the advantages that the flange and the spherical head are integrally formed through the wax mold precision casting, the distribution plate and the spherical head are assembled through the interference fit assembling process, the processing procedures are few, the machining allowance is small, the material waste and the processing cost are reduced, the work efficiency is improved, the nozzle has high machining precision and good consistency, and the desulfurization effect and efficiency are improved, and the stability of device operation is improved.

Description

Technical Field

[0001] This invention relates to the machining of a component in the field of coal coking technology, and in particular to the machining process and casting mold of a nozzle for pre-desulfurization of coke oven gas in the coke oven gas purification process. Background Technology

[0002] HPF catalyst desulfurization and decyanation is a commonly used liquid-phase catalytic oxidation reaction in the wet oxidation desulfurization and decyanation process of coke oven gas using ammonia. The atomization effect of the desulfurization liquid directly determines the efficiency and effect of desulfurization and decyanation. Therefore, the nozzle that atomizes the desulfurization liquid has become one of the key components that restricts the smooth operation of the HPF catalyst desulfurization and decyanation process.

[0003] Chinese patent CN 219442088 U discloses a nozzle for pre-desulfurization of coke oven gas. Employing a swirl and intermediate injection structure, it produces a desulfurized liquid with good atomization, improving the desulfurization efficiency of the desulfurization unit, reducing the number of stages in series-operated desulfurization towers, and significantly lowering investment costs. See [link to patent]. Figure 1 As shown, the nozzle is an irregularly shaped structural component consisting of a spherical head, a flange, and a distribution plate. Currently, the common process involves machining the spherical head separately, welding the spherical head to the flange, and then assembling it with the distribution plate. This process has the following main drawbacks:

[0004] 1) Low machining accuracy and difficulty in controlling nozzle quality directly affect atomization effect: The cost of batch processing of the inner hollow hemisphere of the spherical head using special equipment is too high. Individual processing using ordinary lathes or milling machines is greatly affected by human factors and has dimensional differences. In addition, the welding of the spherical head and flange after separate processing has the impact on the welding quality. The post-weld processing further increases the processing difficulty and reduces work efficiency.

[0005] 2) High processing costs and wasteful materials: The nozzle size is not very large. Spherical heads and flanges are generally made of bars or plates through machining. The machining allowance is large, which is labor-intensive, time-consuming and labor-intensive, resulting in high processing costs and a lot of material waste. The nozzle is also a vulnerable part with a large consumption. The processing cost and material waste remain high.

[0006] 3) Considering ease of processing and installation, the distribution plate floats inside the spherical head, with a large gap between them. After the nozzles are installed on the equipment via flanges and flanges (located on the equipment), the distribution plate is located between the flange and the spherical head. The distribution plate is subject to the impact of the desulfurization liquid under certain pressure and flow rate, which easily causes vibration and generates huge noise. At the same time, there are also issues such as some desulfurization liquid leaking directly from the gap between the distribution plate and the spherical head into the spherical head, and misalignment between the spiral oblique hole and the inner wall of the spherical head, which affect the desulfurization effect.

[0007] 4) Practice has shown that, according to the existing process, although the structures are the same, the atomization effect produced by nozzles from different batches of processing varies greatly, which directly affects the effect and efficiency of desulfurization and decyanation, and the system operation stability is poor. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, the technical problem solved by this invention is to provide a processing method for nozzles used in coke oven gas pre-desulfurization. The flange and spherical head are integrally formed by precision casting using wax molds, and the distribution plate and spherical head are assembled using interference fit or adhesive bonding processes. This reduces the number of processing steps, minimizes processing allowance, reduces material waste and processing costs, and improves work efficiency. The manufactured nozzles have high processing precision and good consistency, thereby improving the desulfurization effect and efficiency, and enhancing the stability of the equipment operation.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A method for processing a nozzle for pre-desulfurization of coke oven gas includes the following steps:

[0011] Step 1: Flange and spherical head machining:

[0012] 1) The flange and spherical head are cast using wax pattern precision casting process. The mating surface C with the outer circle of the distribution plate is reserved with a machining allowance of 0.3 to 0.6 mm. The rest are cast in one piece. The surface roughness of the inner surface of the spherical head and the injection hole is not less than Ra12.5, and the surface roughness of the rest is not less than Ra25.

[0013] 2) Design tolerances according to interference fit or clearance fit, machine the mating surface C with the outer circle of the distribution plate and the surface roughness is not less than Ra3.2;

[0014] Step 2, Distribution plate processing:

[0015] 3) For sheet metal blanking, the surface roughness of the blanking opening shall not be less than Ra50;

[0016] 4) Rough turn the outer diameter, leaving a machining allowance of 0.3 to 0.6 mm, and the surface roughness shall not be less than Ra12.5;

[0017] 5) The surface roughness of both end faces, namely the upper end face (A face) and the lower end face (B face), shall not be less than Ra12.5;

[0018] 6) Drill straight holes on a lathe with a surface roughness of not less than Ra12.5;

[0019] 7) Milling machine drills inclined holes with a surface roughness of not less than Ra12.5;

[0020] 8) Design tolerances according to interference fit or clearance fit, and precision machine the outer circle that mates with the flange and the C-face of the spherical head, with a surface roughness of not less than Ra3.2;

[0021] Step 3, Assembly:

[0022] 9) Inspection: Inspect the overall dimensions of the flange, spherical head, and distribution plate, as well as the dimensions and roughness of each machined surface, to ensure they meet the process requirements;

[0023] 10) Install the distribution plate, flange and spherical head together with an interference fit, or with a clearance fit and apply metal glue to bond them together.

[0024] A precision casting mold for a flange and spherical head of a nozzle used for pre-desulfurization of coke oven gas includes a lower mold, a cylindrical spherical core, a lower disc spring, a flange bolt core, a locating pin, an upper mold, a conical core, an upper disc spring, a nut, and a double-ended stud. The upper part of the cylindrical spherical core is threadedly connected to the double-ended stud. The upper and lower molds are positioned vertically by locating pins and fixedly connected by the cylindrical spherical core, the double-ended stud, and the nut. The lower disc spring is fitted on the cylindrical spherical core and located between the cylindrical spherical core and the lower mold. The conical core, with its small end facing down, is fitted on the double-ended stud and located between the nut and the upper mold. The lower part is positioned by a ramp boss on the upper mold and a shoulder on the double-ended stud. The upper part is positioned between the upper mold and the upper mold by an upper disc spring. The flange bolt core passes through the cylindrical spherical core and the lower mold from bottom to top, with its upper end abutting against the upper mold for positioning and its lower end fixedly connected to the cylindrical spherical core by threads.

[0025] Furthermore, while the nut and the double-ended stud are tightened to fix the upper and lower molds, the lower and upper disc springs are compressed and deformed.

[0026] Furthermore, the upper disc spring can buffer the pressure applied to the conical core by the nut to prevent the conical core from sinking or shifting due to excessive force, thus ensuring accurate positioning of the conical core.

[0027] Furthermore, the upper mold has 2 to 4 wax injection ports evenly distributed on it.

[0028] Furthermore, the distribution plate and flange can also be connected to the spherical head by clearance fit and metal adhesive, or by threaded connection.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1) The flange and spherical head are precision cast in one piece using wax molds, which eliminates the machining processes of the flange and flange hole, the inner and outer spheres of the spherical head and the injection port. At the same time, it also eliminates the welding process between the flange and the spherical head. The number of machining processes is small, the machining allowance is small, the material waste is reduced, and the processing cost is low.

[0031] 2) The spherical head's inner sphere and spray nozzle are both cast in one piece, without the influence of human factors, eliminating dimensional differences, ensuring good processing consistency, improving nozzle quality, and thus improving the nozzle's atomization effect;

[0032] 3) The distribution plate and the spherical head are connected by interference fit, bonding or threaded connection, which eliminates the previous problems such as desulfurization liquid leaking directly into the spherical head from the gap between the distribution plate and the spherical head, and misalignment between the spiral oblique hole and the inner wall of the spherical head, which affect the desulfurization effect. At the same time, the distribution plate and the spherical head are firmly connected, which can withstand the impact of desulfurization liquid with a certain pressure and flow rate without vibration, thus eliminating noise.

[0033] 4) The mold has a simple structure, is easy to manufacture, and has a reasonable, simple, and easy-to-implement process. It has low processing and manufacturing costs and is the best processing route for nozzles and other irregularly shaped structural parts with large batch production.

[0034] 5) Practice has proven that the nozzles manufactured according to the technical solution of this invention have high processing precision and good product consistency, which can greatly improve the desulfurization effect and efficiency of the desulfurization device and improve the stability of system operation. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 This is a schematic diagram of the structure and principle of the nozzle in an embodiment of the present invention;

[0037] Figure 2 This is a schematic front view illustrating the structural principle of the nozzle distribution plate in an embodiment of the present invention;

[0038] Figure 3 This is a top view illustrating the structural principle of the nozzle distribution plate in an embodiment of the present invention;

[0039] Figure 4 This is a bottom view illustrating the structural principle of the nozzle distribution plate in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram illustrating the structural principle of the nozzle flange and the spherical head wax mold precision casting mold in an embodiment of the present invention;

[0041] Figure 6 yes Figure 5 A partially enlarged structural diagram of part I in the diagram;

[0042] Figure 7 This is a schematic diagram illustrating the structural principle of the flange and spherical head integrally precision cast according to an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] In the diagram: 1-Spherical head; 11-Injection hole; 2-Flange; 3-Distribution plate; 31-Straight hole; 32-Angled hole; 321-1#Angled hole; 322-2#Angled hole; 323-3#Angled hole; 324-4#Angled hole; 325-5#Angled hole; 326-6#Angled hole; 7-Flange and spherical head; 71-Lower mold; 72-Columnar spherical core; 73-Lower disc spring; 74-Flange bolt core; 75-Locking pin; 76-Upper mold; 77-Wax injection port; 78-Conical core; 79-Upper disc spring; 80-Nut; 81-Double-ended stud. Detailed Implementation

[0045] In the description of this invention, it should be understood that the terms "left", "right", "up", "down", "front", "back", "horizontal", "vertical", "longitudinal", "lateral", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0047] See Figures 1-7 As shown, the present invention relates to a nozzle for pre-desulfurization of coke oven gas, the processing of which includes the following steps:

[0048] Step 1, Machining of the flange and spherical head 7:

[0049] 1) Using the wax pattern precision casting molds for the flange and spherical head 7, the flange and spherical head 7 are cast using the wax pattern precision casting process (see...). Figure 7 As shown), the mating surface C with the outer circle of the distribution plate 3 has a machining allowance of 0.3 to 0.6 mm (nominal size Ф42 mm, casting forming size Ф41.5 mm). The rest are all cast in one piece. The surface roughness of the inner surface of the spherical head (R20 mm inner sphere) and the injection hole 11 (Ф12 mm conical hole, Ф8 mm straight hole) is Ra12.5, and the surface roughness of the rest is not less than Ra25.

[0050] 2) Select according to the interference fit design tolerance. Machining surface C (the mating surface Ф41.5 of the outer circle of distribution plate 3) yields the following dimensions: With a surface roughness of Ra3.2, the flange and spherical head 7 are obtained, eliminating the machining processes of the flange and flange hole, the inner and outer spheres of the spherical head and the injection port 11. At the same time, the welding process between the flange and the spherical head is also eliminated. The machining process is reduced, the machining allowance is small, the material waste is reduced, and the processing cost is low.

[0051] Step 2, processing of distribution plate 3:

[0052] 3) Plate blanking: Select Q235A plate with a thickness of 21mm, use plasma cutting to cut a Ф43mm diameter round blank, clean the blanking opening, and ensure that the surface roughness is not less than Ra50 to obtain a Ф43×21 blank.

[0053] 4) Rough turn the outer diameter from Ф43mm to Ф42.5mm (leaving a finishing allowance of 0.3 to 0.6mm), and the surface roughness is Ra12.5;

[0054] 5) Both ends of the car, i.e., the upper end (A side, see details) Figure 2 (as shown) and the lower end face (surface B, see details) Figure 2 (As shown) and burrs were removed, and the surface roughness was Ra12.5, resulting in a semi-finished product with a diameter of Ф42.5x20mm;

[0055] 6) Drill a straight hole 31 on a lathe with a surface roughness of Ra12.5 to obtain a straight hole with a diameter of Ф5.7mm;

[0056] 7) Drill a 32mm inclined hole on a milling machine with a surface roughness of Ra12.5 to obtain a 6-Ф6mm spiral inclined hole;

[0057] 8) Select according to the interference fit design tolerance. The outer diameter Ф42.5mm is precision machined (to mate with the C-face of the flange and the spherical head 7). The dimension after machining is Ф42±0.08mm, and the surface roughness is Ra3.2, thus obtaining the distribution plate 3.

[0058] Unlike general machining processes, the precision turning of Ф42±0.08mm is performed after the milling machine drilling of 6-Ф6mm spiral inclined holes. This avoids clamping damage during the milling machine drilling of 6-Ф6mm holes, which would affect machining accuracy.

[0059] Step 3, Assembly Process:

[0060] 9) Inspection: Inspect the overall dimensions, dimensions of each machined surface, and surface roughness of the flange, spherical head 7, and distribution plate 3 to ensure they meet the process requirements;

[0061] 10) Fit the distribution plate 3 with the flange and the spherical head 7 with an interference fit (selection) Simply drive it in with a wooden mallet (easy to install) and install them together.

[0062] The nozzles obtained using the processing technology of this invention have the following characteristics:

[0063] 1) A Ф5.7mm through hole 31 is drilled in the center of the distribution plate 33. Six Ф6mm oblique holes 32 are drilled around the outer perimeter using a universal milling machine in a clockwise or counterclockwise sequence. The lower position of the oblique holes 32 corresponds to the bottom position of the adjacent upper holes (see...). Figure 3 , Figure 4 (as shown);

[0064] 2) More accurately ensures that the outer diameter of the spiral oblique hole 32 distribution circle is equal to the inner diameter of the spherical head 1, that is, both are 40mm. At the same time, it eliminates the impact and movement of the distribution plate 3. The desulfurization liquid from the spiral oblique hole 32 flows precisely to the inner wall of the ball valve system, eliminating the previous problems such as the desulfurization liquid leaking directly into the spherical head from the gap between the distribution plate 3 and the spherical head, and the misalignment between the spiral oblique hole 32 and the inner wall of the spherical head, which affect the desulfurization effect.

[0065] 3) The inner wall R20 and injection hole 11 of the spherical head are precision cast in one piece, which reduces the influence of human factors, makes the dimensions more accurate and the product consistency higher, and eliminates the fluctuation of nozzle atomization effect caused by machining precision as much as possible, which significantly improves the atomization effect of the nozzle on desulfurization liquid.

[0066] A precision casting mold for a flange and spherical head 7 of a nozzle used for pre-desulfurization of coke oven gas includes a lower mold 71, a cylindrical spherical core 72, a lower disc spring 73, a flange bolt core 74, a locating pin 75, an upper mold 76, a conical core 78, an upper disc spring 79, a nut 80, and a double-ended stud 81. The upper part of the cylindrical spherical core 72 is threadedly connected to the double-ended stud 81. The upper mold 76 and the lower mold 71 are positioned vertically by the locating pin 75 and fixedly connected by the cylindrical spherical core 72, the double-ended stud 81, and the nut 80. Spring 73 is fitted onto cylindrical spherical core 72 and located between cylindrical spherical core 72 and lower mold 71; tapered core 78 is fitted onto double-ended stud 81 with its small end facing down and located between nut 80 and upper mold 76, with its lower part positioned by the ramp boss on upper mold 76 and the shoulder on double-ended stud 81, and its upper part positioned between upper mold 76 and upper mold 76 by an upper disc spring 79; flange bolt core 74 passes through cylindrical spherical core 72 and lower mold 71 from bottom to top, with its upper end abutting against upper mold 76 for positioning, and its lower end fixedly connected to cylindrical spherical core 72 by threads.

[0067] Furthermore, while the nut 80 and the double-ended stud 81 are tightened to fix the upper mold 76 and the lower mold 71, the lower disc spring 72 and the upper disc spring 79 are deformed under pressure.

[0068] Furthermore, the upper disc spring 79 can buffer the pressure applied to the conical core 78 by the nut 80 to prevent the conical core 78 from sinking or shifting due to excessive force, so as to ensure the accurate positioning of the conical core 78.

[0069] Furthermore, the upper mold 76 is provided with 2 to 4 wax injection ports 77 evenly distributed.

[0070] The method for making the wax model of the flange and spherical head, i.e., the method for using the casting mold, is as follows:

[0071] 1) The mold components are connected and assembled according to the connection relationship described above to obtain the wax model cavity of the flange and the spherical head 7;

[0072] 2) Inject wax into the wax mold cavity of the flange and spherical head 7 according to the process from wax injection port 77;

[0073] 3) After wax injection, remove the mold and rotate in the opposite direction (loosen the threads) to pull out the flange bolt core 74; loosen the nut 80, and the cylindrical spherical core 72, under its own weight and the elastic force of the lower disc spring 73 (which recovers after being deformed by pressure), loosens and separates from the flange and spherical head 7 wax mold and is pulled downwards. At the same time, the conical core 78, under the elastic force of the upper disc spring 79 (which recovers after being deformed by pressure), loosens and separates from the flange and spherical head 7 wax mold and bounces upwards and is pulled out. Core removal is easier and facilitates the complete molding of the wax mold, reducing the amount of mold repair work; pull out the positioning pin 75, disassemble the lower mold 71, and blow or suck out the wax part with compressed air to complete the production of a flange and spherical head 7 wax mold.

[0074] After the wax model is completed, the precision casting of the flange and spherical head 7 can be completed through processes such as mold repair, shell manufacturing, drying, baking, pouring, solidification, and shell removal.

[0075] To obtain castings with high dimensional accuracy and surface finish, the wax model itself must first possess high dimensional accuracy and surface finish. However, the factors affecting the dimensional accuracy of the wax model during manufacturing are complex. The more process parameters and the more complex the structure, the greater the variation in dimensional accuracy. Taking the nozzle in this embodiment as an example, if the spherical head 1, flange 2, and distribution plate 3 were integrally formed using precision casting of the wax model, it would be technically feasible. However, to obtain castings with the same dimensional accuracy and surface finish, the requirements and difficulty of mold making and subsequent shell-making processes would increase exponentially, significantly increasing costs. Therefore, using the process of this invention, the flange and spherical head are integrally formed using precision casting, the distribution plate is machined using conventional lathes and milling machines, and then assembled together. This process results in a simple mold structure, convenient manufacturing, fewer processing steps, smaller machining allowances, reduced material waste and processing costs, and produces nozzles with high machining accuracy and good consistency, representing the optimal process route for nozzle manufacturing.

[0076] Furthermore, the distribution plate 3 and the flange can be connected to the spherical head 7 by a clearance fit and metal adhesive, or by a threaded connection. This eliminates the previous problems of desulfurization liquid leaking directly into the spherical head from the gap between the distribution plate and the spherical head, and misalignment between the spiral oblique hole 32 and the inner wall of the spherical head, which could affect the desulfurization effect. At the same time, the distribution plate and the spherical head are firmly connected, which can withstand the impact of desulfurization liquid with a certain pressure and flow rate without vibration, thus eliminating noise.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for processing a nozzle for pre-desulfurization of coke oven gas, characterized in that, Includes the following steps: Step 1: Flange and spherical head machining: 1) The flange and spherical head are cast using a wax pattern precision casting process. A machining allowance of 0.3~0.6mm is reserved on the mating surface C with the outer circle of the distribution plate. The remaining parts are cast in one piece. The surface roughness of the inner surface of the spherical head and the injection hole is not less than Ra12.5, and the surface roughness of the remaining surfaces is not less than Ra25; 2) An interference fit is used. Design tolerances, machine the mating surface C with the outer circle of the distribution plate, and ensure the surface roughness is not less than Ra3.2; Step 2, distribution plate machining: 3) For sheet metal blanking, the surface roughness of the blanking opening shall not be less than Ra50; 4) Rough turn the outer diameter, leaving a machining allowance of 0.3~0.6mm, and the surface roughness shall not be less than Ra12.5; 5) The surface roughness of the upper and lower end faces of the vehicle shall not be less than Ra12.5; 6) Drill straight holes on a lathe with a surface roughness of not less than Ra12.5; 7) Milling machine drills inclined holes with a surface roughness of not less than Ra12.5; 8) According to interference fit Design tolerances, precision machined outer circle that mates with flange and spherical head C surface with a surface roughness of not less than Ra3.2; Step 3, Assembly: 9) Inspection: Inspect the overall dimensions of the flange, spherical head, and distribution plate, as well as the dimensions and roughness of each machined surface, to ensure they meet the process requirements; 10) Simply install the distribution plate, flange, and spherical head together with an interference fit.

2. The processing method of a nozzle for pre-desulfurization of coke oven gas according to claim 1, characterized in that, The precision casting mold for the flange and spherical head consists of a lower mold, a cylindrical spherical core, a lower disc spring, a flange bolt core, a locating pin, an upper mold, a conical mold, an upper disc spring, a nut, and a double-ended stud. The upper part of the cylindrical spherical core is threadedly connected to the double-ended stud. The upper and lower molds are positioned vertically by locating pins and fixedly connected by the cylindrical spherical core, the double-ended stud, and the nut. The lower disc spring is fitted onto the cylindrical spherical core and is located between the cylindrical spherical core and the lower mold. The conical mold, with its small end facing down, is fitted onto the double-ended stud and is located between the nut and the upper mold. The lower part is positioned by a ramp boss on the upper mold and a shoulder on the double-ended stud. The upper part is connected to the upper mold by an upper disc spring. The flange bolt core passes through the cylindrical spherical core and the lower mold from bottom to top, with its upper end abutting against the upper mold for positioning and its lower end fixedly connected to the cylindrical spherical core by threads.

3. The processing method of a nozzle for pre-desulfurization of coke oven gas according to claim 2, characterized in that, While the nut and double-ended stud are tightened to fix the upper and lower molds, the lower disc spring and the upper disc spring are compressed and deformed.

4. The processing method of a nozzle for pre-desulfurization of coke oven gas according to claim 2, characterized in that, The upper disc spring can buffer the pressure applied to the conical die by the nut.

5. The processing method of a nozzle for pre-desulfurization of coke oven gas according to claim 2, characterized in that, The upper mold has 2 to 4 wax injection ports evenly distributed on it.

Images