Regenerative double-chamber D-type roasting vertical kiln connection channel

Abstract

This invention relates to the field of metallurgical building materials production equipment technology, and in particular to a regenerative double-chamber D-type vertical kiln connecting channel. The channel includes a connecting channel body placed between the two kilns. The connecting channel is divided into channel one and channel two by side walls on both sides and a partition wall in the middle of the side walls. A double-layered upper arch is provided between each side wall and the partition wall. Pre-fabricated double-channel arches for calcined components are provided on the left and right sides of each channel. Inverted V-shaped protrusions are provided at the bottom of both channels one and two. The V-shaped structure at the bottom of the channel in this invention reduces the distance between the two kiln chambers, preventing small particles from accumulating on the inclined surface at the bottom of the channel, thus improving calcination quality and extending the overall service life of the vertical kiln.

Description

Technical Field

[0001] This invention relates to the field of metallurgical building materials production equipment technology, and in particular to a regenerative double-chamber D-type roasting vertical kiln connection channel. Background Technology

[0002] The regenerative double-chamber vertical kiln is a light-fired kiln used for calcining ores such as limestone, dolomite, and magnesite. It is a widely used kiln that reduces emissions and saves energy. The calcination and heat storage functions of its two chambers are interchangeable; one chamber calcines while the other stores heat, switching roles after 12-30 minutes. Besides circular double-chamber kilns, there are also double-C and double-D types. Currently, the circular double-chamber lime kilns in China are all based on the Swiss Maeltz kiln type. The core structure of this type is an annular design with connecting channels. This structure greatly improves heat utilization efficiency, but its disadvantages include the channels being prone to blockage requiring jacking and cleaning, and the refractory bricks in the channel area being easily damaged and collapsed, further blocking the channels. This directly affects process control, product quality, and the service life of the refractory materials inside the kiln. Therefore, it is essential to explore and invent a connecting channel with higher structural strength to improve kiln lifespan and production efficiency.

[0003] In the existing D-type double-chamber kiln, during the production process, such as Figure 1 As shown, the bottom of the connecting channel is a convex structure with a trapezoidal cross-section. During long-term use, material tends to accumulate at the bottom of the channel, which can easily cause damage to the lining bricks due to prolonged exposure to high temperatures, thermal shock changes in the channel area, creep, compression, low-melting-point erosion and spalling, wear of solid materials, and erosion by moisture in the preheating zone. This can affect the service life of the connecting channel. When the channel is damaged to a certain extent, most of the lining of the double-chamber kiln needs to be replaced. Replacement requires kiln shutdown for maintenance, and the entire lining needs to be removed and rebuilt, which affects the production schedule. Summary of the Invention

[0004] This invention provides a regenerative double-chamber D-type vertical kiln connection channel to improve its shock resistance, thermal stability, corrosion resistance, integrity, wear resistance, and structural strength, ensuring smooth airflow between the kiln chambers, improving kiln process conditions, and extending the overall service life of the kiln.

[0005] In one aspect of this invention, a regenerative double-chamber D-type vertical kiln connecting channel is provided, including a connecting channel body placed between the double-chamber kilns. The connecting channel is divided into channel one and channel two by the front and rear side walls and the partition wall in the middle of the side walls. A double-layer upper arch is provided between each side wall and the partition wall. A double-channel arch for prefabricated roasting parts is provided on the left and right sides of each channel. An inverted V-shaped protrusion is provided at the bottom of channel one and channel two respectively.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0007] The bottom of the channel in this invention adopts an inverted V-shaped structure, which minimizes the spacing between the D-type kiln chambers and prevents small particles calcined and heated inside the kiln from accumulating on the sloping bottom surface of the channel and being unable to flow smoothly downwards, thus affecting the calcination quality of the material. End walls and door arches are added to both sides of each channel below the double-layered upper arch, respectively, increasing the channel's strength. The inverted V-shaped bottom structure optimizes the channel space, ensuring smooth airflow between the two kiln chambers, which is beneficial for the ignition of the double-D kiln and allows for more stable combustion of the burners, meeting the kiln heating process requirements.

[0008] Furthermore, the preferred embodiment adopted in this invention is:

[0009] Each side wall has an end wall between its upper part and the upper part of the partition wall, and a precast, double-channel archway is installed below the end wall.

[0010] The raised surface layer at the bottom of Channel 1 and Channel 2 is constructed with magnesium aluminum spinel bricks, and the raised inner layer is constructed with high alumina bricks to form a tower structure. The lower part of the refractory material between the raised surface layer and the raised inner layer is low cement clay refractory castable, and the top curved surface refractory material between the raised surface layer and the raised inner layer is reinforced high alumina steel fiber wear-resistant refractory.

[0011] The double-layer top arch includes a double-channel lightweight high-alumina brick top arch placed on top and a precast double-channel top arch placed on the bottom. The precast double-channel top arch and the precast double-channel door arch are respectively made of reinforced high-alumina steel fiber wear-resistant castable material and are fired into shape.

[0012] The top of the inverted V-shaped protrusion has an arc-shaped structure. Attached Figure Description

[0013] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. In the drawings:

[0014] Figure 1 This is a schematic diagram of the connection channel of an existing roasting vertical kiln;

[0015] Figure 2 This is a schematic diagram of the overall structure of the present invention;

[0016] Figure 3 for Figure 2 AA section view;

[0017] Figure 4 for Figure 3 Sectional view 2-2;

[0018] Figure 5 for Figure 1 BB cross-sectional view;

[0019] In the diagram: 1. Raised surface layer; 2. Raised inner layer; 3. Lower filling material between the raised surface layer and the raised inner layer; 4. Top curved surface filling material between the raised surface layer and the raised inner layer; 5. Side wall; 6. End wall; 7. Double-channel top arch of precast fired component; 8. Double-channel lightweight high-alumina brick top arch of precast fired component; 9. Arch corner brick; 10. Channel 1; 12. Channel 2; 13. Partition wall. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0021] like Figures 2 to 4 As shown:

[0022] A regenerative double-chamber D-type vertical kiln connecting channel mainly includes a connecting channel body, which is placed between the two kilns to connect them.

[0023] The connecting channel is divided into channel one 11 and channel two 12 by side walls 5 placed on the front and rear sides and partition wall 13 placed between the two side walls 5. The top of each side wall 5 and the top of the partition wall 13 are respectively provided with double-layer top arches. In this embodiment, the double-layer top arches are a double-channel lightweight high-alumina brick top arch 8 placed on the upper side and a precast calcined component double-channel top arch 7 placed on the lower side.

[0024] End walls 6 are provided on the left and right sides of the top of channel 11 and channel 22 respectively, and a precast sintered double-channel arch 9 is provided below the end walls 6.

[0025] In this embodiment, the precast double-channel arch 9 and the precast double-channel top arch 7 are respectively made of reinforced high-alumina steel fiber wear-resistant castable material and are fired in a special firing kiln. After reaching the corresponding physical and chemical indicators and structural strength standards, they are laid together with the channel refractory bricks in strict accordance with the standard requirements for vertical kiln construction. During construction, the brick joints and expansion joints should be strictly controlled. For example, the brick joints should be controlled to be no more than 2mm, and the span of the expansion joints should be strictly controlled based on the expansion coefficient determined by the Li Hua standard for different refractory materials.

[0026] In this embodiment, the corner bricks of the precast double-channel arch 9, the precast double-channel top arch 7, and the double-channel lightweight high-alumina brick top arch 8 are all made of reinforced high-alumina bricks.

[0027] The bottom of Channel 11 and Channel 22 are respectively provided with inverted V-shaped protrusions. The surface layer 1 of the protrusion is made of magnesium aluminum spinel bricks, and the inner layer 2 of the protrusion is a tower structure made of high alumina bricks. The lower part of the surface layer and the inner layer of the protrusion is filled with low cement clay material (low cement clay material is poured at the lower part of the surface layer and the inner layer of the protrusion). The top curved surface of the surface layer and the inner layer of the protrusion is filled with reinforced high alumina steel fiber wear-resistant and refractory castable.

[0028] In this embodiment, the inclination angle of the raised surfaces on both sides of the inverted V-shaped protrusion is α. The inclination angle α should be minimized, that is, the distance between the D-shaped kiln chambers should be minimized, and thus the length of the channel should also be reduced. In this embodiment, α is 15.16°. By setting the inverted V-shaped protrusion, the small particles of material being calcined and heated in the kiln chamber can flow smoothly downwards without accumulating on the inclined bottom surface of the channel, thus affecting the calcination quality of the material.

[0029] The structure and calcination principle of the regenerative double-chamber vertical kiln are as follows:

[0030] The two kiln chambers are the calcination chamber (i.e., kiln chamber A) and the heat storage chamber (i.e., kiln chamber B). The calcination chamber and the heat storage chamber are connected by a connecting channel. The working state of the two kiln chambers is generally switched every 12 to 15 minutes.

[0031] The double-chamber vertical kiln is an advanced lime calcination equipment. It has two vertical kiln chambers connected by two connecting channels in the lower part of the chambers. The double-chamber kiln calcination process has two main characteristics: parallel flow and heat storage. Parallel flow means that during limestone calcination, the combustion products and limestone flow downwards together, which is beneficial for producing high-quality active lime. Heat storage means that during calcination in kiln A, the calcination products—high-temperature flue gas—enter kiln B through the two connecting channels in the lower part of kiln A. After entering kiln B, the high-temperature flue gas flows upwards, preheating the limestone in the preheating zone to a higher temperature. This process is equivalent to storing the heat of the flue gas in the preheating zone of kiln B. After passing through kiln B, the flue gas cools down to a very low temperature before exiting the kiln. This working principle makes full use of the waste heat of the flue gas, ensuring that the kiln has high thermal efficiency. The calcination and heat storage functions of the two kiln chambers of the double-chamber kiln are alternated.

[0032] The connecting channel between the double-chamber vertical kilns is an essential structure for realizing the calcination principle and achieving energy-saving and high thermal efficiency advantages. In this embodiment, the function of the connecting channel is to allow the gas generated during the calcination process in the lime calcination kiln to rise from the calcination chamber to the top of the inverted V-shaped protrusion at the bottom of the connecting channel body before entering the regenerator kiln. The large amount of dust carried in the flowing gas will fall to the bottom of the channel with the gas. Due to the inverted V-shaped protrusion structure at the bottom of the channel in this embodiment, the dust will flow downward along the slope of the bottom surface of the connecting channel body to prevent accumulation on the bottom surface of the connecting channel body.

[0033] This invention employs a composite masonry structure combining refractory calcined precast components and refractory bricks, resulting in improved thermal shock resistance, corrosion resistance, integrity, wear resistance, and structural strength. The optimized design enhances the overall strength of the connecting channel body and increases its space, ensuring smooth airflow between the two kiln chambers. This guarantees continuous and stable combustion of the ignition burners during kiln opening, improves the process conditions of the vertical kiln, and extends the overall service life of the connecting channel.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A regenerative double shaft D-type calcining kiln connecting channel comprising a connecting channel body placed between the double shaft kiln furnaces, characterized in that: The connecting passage is divided into passage one and passage two by the front and rear side walls and the partition wall between the side walls, double-layer upper arches are arranged between each side wall and the partition wall, and double-channel door arches of prefabricated baking parts are arranged on the left and right sides of each passage; End walls are arranged between the upper part of each side wall and the upper part of the partition wall, and double-channel door arches of prefabricated baking parts are arranged below the end walls; The top of the inverted V-shaped protrusion is in an arc structure; The inclination angle of the protrusion surface layer on the two sides of the inverted V-shaped protrusion is less than or equal to 15.16°.

2. The regenerative double-muffle D-type shaft kiln connecting passage according to claim 1, characterized in that: The protrusion surface layer at the bottom of passage one and passage two is built by using magnesia-alumina spinel bricks, the protrusion inner layer is built by using high-alumina bricks into a tower structure, the lower part between the protrusion surface layer and the protrusion inner layer is filled with low-cement clay refractory castable, and the top curved surface between the protrusion surface layer and the protrusion inner layer is filled with reinforced high-alumina steel fiber wear-resistant castable.

3. The regenerative double shaft D-type calcination shaft kiln connecting passage as claimed in claim 1, wherein: The double-layer upper arch includes a double-channel light high-alumina brick top arch arranged above and a double-channel top arch of prefabricated baking parts arranged below, and the double-channel top arch of prefabricated baking parts and the double-channel door arch of prefabricated baking parts are respectively formed by baking reinforced high-alumina steel fiber wear-resistant castable.

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