Process nozzle structure for reducing pressure difference fluctuation

Abstract

The utility model provides a process nozzle structure for reducing differential pressure fluctuation, which comprises a central oxygen pipe, a coal slurry pipe, an outer oxygen pipe and a cooling water coil pipe which are assembled and connected from inside to outside, pure oxygen sprayed by the central oxygen pipe and the outer oxygen pipe and coal water slurry sprayed by the coal slurry pipe are mixed and then enter a gasification furnace for chemical reaction, and a nozzle head, the inclination angle of the nozzle outer slope of the central oxygen pipe is consistent with the inclination angle of the nozzle inner slope of the coal slurry pipe. The nozzle has the advantages that the structural design is reasonable, the design size of the nozzle head is improved, and the pressure fluctuation of the premixing chamber of the nozzle head is improved, so that the atomization effect of the nozzle is improved, and the service life of the nozzle is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of process nozzles for water-coal slurry gasification furnaces, in particular to a process nozzle structure capable of alleviating pressure difference fluctuations. Background Art

[0002] The process nozzle is installed on the top of the coal gasifier. Its function is to grind dry coal powder, water-coal slurry or other organic solutions in a certain ratio to produce qualified coal slurry, which is pre-mixed with pure oxygen from the air separation unit through the process nozzle and then enters the gasifier. Chemical reactions are carried out under a certain temperature and pressure to produce crude synthesis gas with CO+H2 as the main components. The crude synthesis gas is sent to the post-system purification device for further processing.

[0003] like Figure 1 、 2 As shown, the process nozzle is typically composed of an outer oxygen assembly, a coal slurry assembly, a central oxygen assembly, and other flow channels. Each component is equipped with external interfaces, and each head is equipped with a corresponding nozzle. The components are assembled and connected by bolts after the head atomization size is controlled. In actual production operations, large fluctuations in the coal slurry pressure differential across the nozzle are common. This pressure fluctuation reduces the nozzle's atomization effect and service life, seriously restricting the long-term stable operation of the gasifier. Utility Model Content

[0004] The purpose of the utility model is to provide a process nozzle structure with reasonable structural design, improved premixing chamber pressure fluctuation, enhanced atomization effect, extended service life, and reduced coal slurry pressure difference fluctuation.

[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0006] A process nozzle structure for reducing pressure difference fluctuations includes a central oxygen pipe, a coal slurry pipe, an outer oxygen pipe and a cooling water coil assembled and connected from the inside to the outside. The pure oxygen sprayed from the central oxygen pipe and the outer oxygen pipe is mixed with the water-coal slurry sprayed from the coal slurry pipe and then enters the gasifier for chemical reaction. At the nozzle head, the inclination angle of the outer bevel of the nozzle of the central oxygen pipe is consistent with the inclination angle of the inner bevel of the nozzle of the coal slurry pipe.

[0007] The above nozzle structure is not only applicable to water-coal slurry process nozzles, but also to pulverized coal nozzles or nozzles of other gasification forms.

[0008] Furthermore, the inclination angle of the outer slope of the nozzle of the central oxygen pipe and the inclination angle of the inner slope of the nozzle of the coal slurry pipe are adjusted in the range of 20° to 70° according to different working conditions.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] The utility model is a process nozzle structure for reducing pressure difference fluctuations. The structure is reasonably designed. By improving the design size of the nozzle head, the pressure fluctuation of the premixing chamber of the nozzle head is improved, thereby improving the atomization effect of the nozzle and extending the service life of the nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural diagram of the water-coal slurry process nozzle.

[0012] Figure 2 It is a schematic diagram of the assembly structure of the process nozzle head.

[0013] Figure 3 It is a schematic diagram of the nozzle structure of a traditional water-coal slurry process nozzle.

[0014] Figure 4 This is a schematic diagram of the structure of the process nozzle head before transformation of the utility model.

[0015] Figure 5 It is a schematic diagram of the structure of the process nozzle head after the modification of the utility model.

[0016] Figure 6 This is a schematic diagram of the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber before the modification of Example 1 of the utility model.

[0017] Figure 7 This is a schematic diagram of the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber after the modification of Example 1 of the utility model.

[0018] Figure 8 This is a schematic diagram of the pressure fluctuation frequency at the nozzle outlet of Example 1 of the present invention before modification.

[0019] Figure 9 This is a schematic diagram of the pressure fluctuation frequency at the nozzle outlet after modification of Example 1 of the utility model.

[0020] Figure 10 This is a schematic diagram of the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber and the nozzle outlet before the modification of Example 2 of the present utility model.

[0021] Figure 11 This is a schematic diagram of the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber and the nozzle outlet after the modification of Example 2 of the utility model. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0023] This utility model is a process nozzle structure that reduces pressure fluctuations. In order to minimize the frequency of pressure fluctuations during use, computer simulation is performed using computational particle fluid dynamics (CPFD) Barracuda software to study the effect of nozzle head size changes on the actual atomization effect of the nozzle. Figure 3 As shown in the figure, through a large amount of simulation data comparison, it was found that when designing the nozzle head size of the traditional water-coal slurry process, there was a difference between the outer bevel angle A of the central oxygen pipe and the inner bevel angle B of the coal slurry pipe. In addition, the outer bevel angle A of the central oxygen pipe is slightly larger than the inner bevel angle B of the coal slurry pipe, forming a bell-shaped channel area that gradually expands. This causes the water-coal slurry to squeeze and contract in area 01 when entering the nozzle from the pipeline, resulting in increased pressure. After passing through the minimum cross-section C and entering area 02, it rapidly expands and the pressure drops instantly. This change causes unstable fluctuations in the coal slurry pressure differential.

[0024] In order to reduce the fluctuation of coal slurry pressure difference during the operation of the process nozzle and improve the service life and atomization effect of the nozzle, the utility model redesigns and calculates the head size of the process nozzle. Figure 4 As shown in the figure, before the transformation, the outer slope angle of the nozzle of the central oxygen tube was 60°, and the inner slope angle of the nozzle of the coal slurry tube was 38°. After simulation calculation, it was found that in the flow channel of the nozzle of the central oxygen tube and the nozzle of the coal slurry tube, the flow velocity of the water-coal slurry from point A1 to point A4 was first increased, then decreased, and finally increased again. This state caused the water-coal slurry flow rate to change frequently here, resulting in large pressure fluctuations when the water-coal slurry enters the premixing chamber, which in turn caused large fluctuations in the overall water-coal slurry pressure difference of the process nozzle, thereby affecting the atomization effect and service life of the process nozzle.

[0025] Based on a large number of simulation calculations, the utility model changes the inner slope angle of the coal slurry pipe nozzle from 38° to 60°, and the outer slope angle of the central oxygen pipe nozzle remains unchanged at 60°. At this time, the water-coal slurry flow rate increases evenly from point B1 to point B4, greatly reducing the pressure fluctuation of the water-coal slurry entering the premixing chamber. Example

[0026] A 40kg-class multi-component slurry gasification process technology project in Ordos, Inner Mongolia, is designed to produce 200,000 tons of porous ammonium nitrate annually in the first phase and 100,000 tons of methanol annually in the second phase. Gasification utilizes a 2.8M φ gasifier with a designed operating pressure of 4.0 MPa and a single furnace load of 24.5 m³ / h. Two gasifiers are in operation, with one in standby. Before the retrofit, the process nozzles suffered from fluctuating operating pressure differentials, short nozzle life, low effective gas content, and high residual carbon content. Simulation analysis and comparison revealed that adjusting the inner slope of the coal slurry to align with the outer slope of the central oxygen pipe nozzle significantly reduced the amplitude and frequency of pressure fluctuations, significantly improving various operating parameters.

[0027] like Figure 6 、 7 The figure shows the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber before and after the nozzle structure modification of Example 1. Specifically, the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber was 0.5 MPa before the modification, while it was 0.11 MPa after the modification. The pressure fluctuation frequency before the modification was 0.39 MPa greater than that after the modification. In other words, the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber with the new nozzle structure can be reduced by 78%.

[0028] Since the pressure fluctuation of water-coal slurry entering the premixing chamber of the new nozzle has been significantly improved, the overall pressure fluctuation of the nozzle has also been significantly improved after the transformation. Figure 8 、 Figure 9 The changes in the overall pressure fluctuation frequency of the nozzle before and after the transformation are given respectively. Figure 8 As shown in Figure 2, the nozzle outlet pressure fluctuation frequency before the modification is 0.18 MPa. Figure 9 As shown in the figure, the nozzle outlet pressure fluctuation frequency after the modification is 0.12MPa, and the nozzle outlet pressure fluctuation difference before and after the modification is 0.06MPa, that is, the nozzle outlet pressure fluctuation after the modification has been significantly improved, reduced by 33%. The significant reduction in the nozzle outlet pressure fluctuation frequency can extend the service life of the nozzle. Example

[0029] A production project in Yulin, northern Shaanxi, with an annual output of 1.8 million tons of methanol, 600,000 tons of olefins, 300,000 tons of LDPE / EVA, and 400,000 tons of polypropylene. The project uses water-coal slurry gasification technology, with a φ3.3M gasifier, a design operating pressure of 6.5MPa, and a single furnace design load of 93.4 m 3 / h. Two gasifiers are in operation, while one is on standby. Before the renovation, the process nozzles experienced significant vibration, low effective gas content, prolonged operation time, and severe surface cracking. Through simulations, the inner bevel angle of the coal slurry pipe nozzle was adjusted to align with the outer bevel angle of the central oxygen pipe nozzle, both at 60°. This means the inner bevel of the coal slurry pipe nozzle is parallel to the outer bevel of the central oxygen pipe nozzle. After the renovation, all nozzle operating indicators remained stable and normal, and the vibration disappeared.

[0030] like Figure 10 、 11 As shown in the figure, the pressure fluctuation frequencies of the water-coal slurry entering the premixing chamber and the nozzle outlet before and after the nozzle structure modification in Example 2 are respectively given. Figure 10As shown in the figure, the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber of the nozzle was 0.3 MPa before the modification, and 0.12 MPa after the modification, which was 0.18 MPa higher before the modification than after the modification, that is, the pressure fluctuation frequency of the water-coal slurry entering the premixing chamber after the modification can be reduced by 60% compared with before the modification. As for the pressure fluctuation frequency of the nozzle outlet, the pressure fluctuation frequency of the nozzle outlet was 0.24 MPa before the modification and 0.11 MPa after the modification, which was 0.13 MPa higher before the modification than after the modification, that is, the pressure fluctuation frequency of the nozzle outlet after the modification can be reduced by 54% compared with before the modification.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the concept of the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process nozzle structure for reducing pressure fluctuations, comprising a central oxygen pipe, a coal slurry pipe, an outer oxygen pipe, and a cooling water coil assembled and connected from the inside out. Pure oxygen ejected from the central and outer oxygen pipes is mixed with water-coal slurry ejected from the coal slurry pipe and then enters a gasifier for a chemical reaction. The structure is characterized by: The nozzle head has an outer slope angle of the central oxygen pipe nozzle that is consistent with an inner slope angle of the coal slurry pipe nozzle.

2. A process nozzle structure for reducing pressure differential fluctuation according to claim 1, characterized in that: The inclination angle of the outer slope of the nozzle of the central oxygen pipe and the inclination angle of the inner slope of the nozzle of the coal slurry pipe are adjusted in the range of 20° to 70° according to different working conditions.

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