A laser cladding overlaying process nozzle

Abstract

The application provides a laser cladding surfacing type process nozzle, which comprises coaxial center oxygen nozzle, coal slurry nozzle and outer oxygen nozzle from inside to outside, and laser cladding surfacing layers are arranged on the outer conical surface of the center oxygen nozzle, the inner conical surface of the coal slurry nozzle and the fire end surface of the outer oxygen nozzle respectively. The application has the advantages that: laser cladding process is adopted to coat the surfacing layers on the outer conical surface of the center oxygen nozzle, the inner conical surface of the coal slurry nozzle and the fire end surface of the outer oxygen nozzle, so as to solve the problems of nozzle abrasion and corrosion, ensure the stable atomization effect of the process nozzle and prolong the service life of the process nozzle.

Description

Technical Field

[0001] This invention relates to the field of process nozzle technology for coal-water slurry gasification furnaces, specifically to laser cladding welding process, and in particular to a laser cladding welding process nozzle. Background Technology

[0002] The prerequisite for stable, long-term operation of process nozzles is good atomization at the burner head, and the prerequisite for stable, good atomization is the stability of the burner head's dimensions and structure. However, in actual operation, the central oxygen nozzle and coal slurry nozzle, due to the high-speed scouring of the coal-water slurry, exhibit severe wear after one service cycle. The worn surfaces often show fish-scale patterns and knife-edge shapes. This wear alters the basic dimensions of the nozzles, leading to changes in the fit between nozzles, thus affecting the atomization effect of the process nozzles under rated load (shift in the atomization black zone). In addition, the external oxygen nozzle extends into the gasifier, with its end face directly facing the combustion zone. Due to the high temperature and pressure inside the furnace, its end face develops radial cracks after one service cycle, and the nozzle orifice also experiences scouring and wear from the coal-water slurry, causing changes in the annular gap, which is also a factor affecting the atomization effect of the process nozzles.

[0003] The size of the process nozzle head, as a whole, is composed of the head sizes of each component and their assembly dimensions. It is precisely calculated based on the operating parameters such as pressure and temperature of the media in each pipeline. If the nozzles of any component become enlarged or damaged due to wear on their outer edges, bevels, or arc surfaces, the balance of the mating dimensions between the nozzles will be disrupted, and the balance of atomization effect in the furnace will also be affected. For example, when the outer edge of the central oxygen nozzle becomes smaller, the combustion reaction zone shifts upward, and the head temperature will inevitably rise, leading to high-temperature ablation of the outer oxygen nozzle end face.

[0004] Therefore, there is an urgent need to propose an improved structure for process nozzles to enhance the wear and corrosion resistance of the nozzles and meet the requirements for convenient disassembly and assembly. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of nozzle wear by laser cladding welding on the surfaces of the central oxygen nozzle, coal slurry nozzle, and outer oxygen nozzle of the coal-water slurry gasifier process nozzle, replacing the high-cost hard alloy bushing of the original coal slurry nozzle, mitigating the corrosion and cracking phenomenon on the end face of the outer oxygen nozzle, and effectively improving the service life and performance of the process nozzle.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A laser cladding welding process nozzle comprises, from the inside out, a coaxial central oxygen nozzle, a coal slurry nozzle, and an outer oxygen nozzle. The outer conical surface of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle, and the fire-facing end face of the outer oxygen nozzle are respectively provided with laser cladding welding layers.

[0007] Furthermore, the laser cladding overlay of the central oxygen nozzle and the coal slurry nozzle is made of one or a combination of Co, W, or Cr.

[0008] Furthermore, the laser cladding overlay of the external oxygen nozzle is made of one or more of the following materials: Cr or Ni.

[0009] Furthermore, the central oxygen nozzle includes a front section and a rear section, which are connected by a threaded connection or a keyway.

[0010] Furthermore, a gasket is provided between the front section and the rear section of the central oxygen nozzle to prevent the central oxygen nozzle from expanding due to heat.

[0011] Furthermore, the coal slurry nozzle includes a front section and a rear section, which are connected by threads, and a gasket is provided between the front section and the rear section.

[0012] Furthermore, the outer conical surface of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle, and the fire-facing end face of the outer oxygen nozzle are respectively machined with serrated grooves, thereby facilitating better adhesion of the laser cladding material.

[0013] Compared with the prior art, the present invention has the following advantages: This invention discloses a laser cladding welding process nozzle. By coating the outer conical surface of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle, and the fire-facing end face of the outer oxygen nozzle with a wear-resistant and corrosion-resistant welding layer, and employing a laser cladding process, the problems of nozzle wear and corrosion are solved, ensuring a stable atomization effect of the process nozzle and extending its service life. Furthermore, the central oxygen nozzle and the coal slurry nozzle are assembled and connected in front and rear sections, which can be disassembled and replaced, facilitating laser cladding and reducing maintenance costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process nozzle structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the central oxygen nozzle structure of the present invention.

[0016] Figure 3 This is a schematic diagram (a) of the assembly structure of the front and rear sections of the central oxygen nozzle of the present invention.

[0017] Figure 4 This is a schematic diagram (II) of the assembly structure of the front and rear sections of the central oxygen nozzle of the present invention.

[0018] Figure 5 This is a schematic diagram of the front section dimension design of the central oxygen nozzle of the present invention.

[0019] Figure 6 This is a schematic diagram of the coal slurry nozzle structure of the present invention.

[0020] Figure 7 This is a schematic diagram of the assembly structure of the front and rear sections of the coal slurry nozzle of the present invention.

[0021] Figure 8 This is a schematic diagram of the structural design of the front section of the coal slurry nozzle of the present invention.

[0022] Figure 9 This is a schematic diagram of the external oxygen nozzle structure of the present invention.

[0023] Figure 10 This is a schematic diagram of the machining process of the outer conical surface of the central oxygen nozzle of the present invention.

[0024] Figure 11 This is a schematic diagram of the machining process of the inner conical surface of the coal slurry nozzle of the present invention.

[0025] Figure 12 This is a schematic diagram of the machining process of the fire-facing end face of the external oxygen nozzle of the present invention.

[0026] Figure 13 This is a schematic diagram illustrating the design effect of the process nozzle size in this invention.

[0027] Reference numerals: 1. Central oxygen nozzle; 11. Front section of central oxygen nozzle; 12. Rear section of central oxygen nozzle; 2. Coal slurry nozzle; 21. Front section of coal slurry nozzle; 22. Rear section of coal slurry nozzle; 3. External oxygen nozzle. Detailed Implementation

[0028] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0029] A laser cladding welding process nozzle, such as Figure 1 As shown, from the inside out, it includes a coaxial central oxygen nozzle 1, a coal slurry nozzle 2, and an outer oxygen nozzle 3. The outer conical surface of the central oxygen nozzle 1, the inner conical surface of the coal slurry nozzle 2, and the fire-facing end face of the outer oxygen nozzle 3 are each provided with a laser cladding weld overlay layer. Preferably, the weld overlay layer thickness is 2 mm.

[0030] The laser cladding overlay of the central oxygen nozzle 1 and the coal slurry nozzle 2 is made of one or more of the following materials: Co, W, or Cr, thereby increasing wear resistance.

[0031] The laser cladding overlay of the external oxygen nozzle 3 is made of one or more of the following materials: Cr or Ni, thereby increasing corrosion resistance.

[0032] like Figure 2As shown, the central oxygen nozzle includes a front section 11 and a rear section 12, which are connected by threads or keyways. A gasket is provided between the front section 11 and the rear section 12 to prevent the central oxygen nozzle from expanding due to heat.

[0033] like Figure 3 As shown, if a threaded connection is used, the front section 11 and the rear section 12 of the central oxygen nozzle are respectively provided with corresponding threaded holes. After being inserted into each other, they are fixedly connected by a locking set screw passing through the threaded holes. Threaded connections are suitable for nozzles with larger sizes and sufficient thread machining allowance.

[0034] like Figure 4 As shown, if a keyway connection is used, the connecting part of the front section 11 of the central oxygen nozzle has a keyway structure, and the rear section 12 of the central oxygen nozzle has a threaded hole. After they are inserted into each other, a locking set screw passes through the threaded hole and abuts against the keyway structure to fix the connection. The keyway connection is suitable for situations where the nozzle size is small and threads cannot be machined.

[0035] like Figure 5 As shown, the central oxygen nozzle front section 11 is the discharge head for internal gas delivery. Its key dimensions are the internal taper 'a' and the straight section L at the orifice, which determine factors such as the flow rate, flow volume, pressure, atomization, and range of the discharged gas. By adopting a portable front and rear section structure, the central oxygen nozzle front section 11 can be serialized. Through practical verification, different nozzles can be manufactured using a complete set of dimensions to meet the selection requirements under different process conditions. Furthermore, replacement is simple and quick; the central oxygen nozzle front section 11 can be removed and replaced with another specification of central oxygen nozzle front section 11 simply by removing the fastening set screw.

[0036] like Figure 6 , 7 As shown, the coal slurry nozzle 2 includes a front section 21 and a rear section 22. The front section 21 and the rear section 22 are connected by threads. A gasket is provided between the front section 21 and the rear section 22. The gasket is relatively soft to prevent the nozzle from expanding due to heat.

[0037] like Figure 8As shown, the coal slurry nozzle 2 is a discharge head for internally conveying coal-water slurry. Its key dimensions are the internal taper b and the straight section L at the nozzle opening. Typically, the inner taper of the coal slurry is 38° or 60°, which matches the outer taper of the central oxygen at 60°. When the internal coal-water slurry is atomized by the action of internal and external oxygen, the slurry is atomized. With a portable, detachable structure, the front section 21 of the coal slurry nozzle can be serialized. Through practical verification, different nozzles can be manufactured with complete sets of dimensions to meet the selection under different process conditions. Furthermore, replacing the nozzle front section is simple and quick; the coal slurry nozzle front section 21 can be removed simply by removing the locking screw, which also facilitates laser cladding.

[0038] like Figure 9 As shown, the laser cladding overlay layer of the external oxygen nozzle 3 is located on its fire-facing end face. The inner cone of the external oxygen nozzle 3 is parallel to the outer cone of the coal slurry nozzle 2, typically set at 60°. like Figure 10 , 11 As shown in Figures 1 and 12, serrated grooves are machined on the outer conical surface of the front section 11 of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle 2, and the fire-facing end face of the outer oxygen nozzle 3, respectively, so as to facilitate better adhesion of the laser cladding material.

[0039] like Figure 13 The diagram shows the design dimensions of the process nozzles. Here, a, b, and c represent the inner tapers of the central oxygen nozzle 1, coal slurry nozzle 2, and outer oxygen nozzle 3, respectively; B1 and B2 represent the annular gaps for oxygen and coal-water slurry transport; L1 and L2 represent the straight sections of the coal slurry and central oxygen nozzles; and X, Y, and Z represent the intersection points of the materials transported inside the nozzles. These parameters are interconnected and mutually restrictive; each dimension is crucial and affects the atomization effect. Taking the central oxygen nozzle 1 as an example: under the rated operating conditions of the process nozzle, the smaller the dimension a, the lower the internal oxygen transport acceleration and velocity, and the smaller the pressure loss. At this time, the central oxygen jet is concentrated, which can increase the gas range. When the dimension a increases, the internal oxygen transport encounters increased resistance, the outlet velocity increases, and the pressure decreases. At this time, the outlet diffusion angle increases, and the spray distance shortens. In addition, the straight section L2 at the nozzle also affects gas atomization. When the straight section is too long, the pressure loss increases, and the range is short; when the straight section is too short, the pressure loss decreases, and the range is long. The above dimensions illustrate that the front and rear positions of the gas intersection dimension X of the central oxygen nozzle 1 can be adjusted to coordinate with the coal slurry nozzle 2 and the external oxygen nozzle 3.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A laser cladding welding process nozzle, comprising, from the inside out, a coaxial central oxygen nozzle, a coal slurry nozzle, and an outer oxygen nozzle, characterized in that: The outer conical surface of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle, and the fire-facing end face of the outer oxygen nozzle are each provided with a laser cladding weld layer.

2. The laser cladding welding nozzle according to claim 1, characterized in that: The laser cladding overlay of the central oxygen nozzle and coal slurry nozzle is made of one or more of the following materials: Co, W, or Cr.

3. The laser cladding welding nozzle according to claim 1, characterized in that: The laser cladding overlay of the external oxygen nozzle is made of one or more of the following materials: Cr or Ni.

4. The laser cladding welding nozzle according to claim 1, characterized in that: The central oxygen nozzle includes a front section and a rear section, which are connected by a threaded connection or a keyway.

5. The laser cladding welding nozzle according to claim 4, characterized in that: A gasket is provided between the front section and the rear section of the central oxygen nozzle to prevent the central oxygen nozzle from expanding due to heat.

6. The laser cladding welding nozzle according to claim 1, characterized in that: The coal slurry nozzle includes a front section and a rear section, which are connected by threads. A gasket is provided between the front and rear sections of the coal slurry nozzle.

7. The laser cladding welding nozzle according to claim 1, characterized in that: The outer conical surface of the central oxygen nozzle, the inner conical surface of the coal slurry nozzle, and the fire-facing end face of the outer oxygen nozzle are respectively machined with serrated grooves to facilitate better adhesion of the laser cladding material.

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