Combustion furnace special for cement plant fuel replacement

Abstract

The utility model relates to the technical field of cement production fuel substitution, in particular to a combustion furnace special for cement plant fuel substitution and a fuel substitution method, the combustion furnace comprises a furnace chamber, the top of the furnace chamber is provided with an air outlet, and the air outlet is connected with a decomposing furnace; air enters from one side of the bottom and is connected with a tertiary air pipe; an alternative fuel inlet is formed in one side of the top of the furnace chamber; a plurality of material dispersing mechanisms are arranged between the alternative fuel inlet and the air inlet in the furnace chamber; and the alternative fuel is heated and combusted by tertiary air from the opposite direction in the falling process in the furnace chamber. On one hand, the mode of relative movement of alternative fuel and tertiary air and the effect of a material dispersing mechanism enable combustion to be more sufficient and ash content to be less, and on the other hand, the design of the furnace chamber structure enables the ash content to enter the rotary kiln in time, and the ash content is prevented from being accumulated in the furnace chamber to be coked.

Description

Technical Field

[0001] This utility model relates to the field of fuel substitution technology in cement production, specifically to a special combustion furnace for cement plants that burns alternative fuels or hazardous waste and other alternative combustibles with calorific value. Background Technology

[0002] The cement industry is a high-energy-consuming and high-emission industry. The production of cement clinker requires large quantities of fossil fuels such as coal, and also releases significant amounts of waste gases into the atmosphere, including carbon dioxide, sulfur dioxide, and nitrogen oxides. Currently, approximately 35% of the cement industry's carbon emissions come from fossil fuels, primarily from coal combustion. Finding alternative fuels and combustion technologies is now urgent for companies, as adopting alternative fuels can also significantly reduce production costs.

[0003] Existing alternative fuel technologies for cement production generally employ hot pan furnaces or stepped furnaces. The alternative fuel burns inside the furnace, and the resulting hot air enters the decomposition furnace, replacing some of the heat generated by pulverized coal. In these furnaces, hot air and material enter in the same direction, heating the fuel and then releasing heat. This results in poor combustion efficiency, and material easily falls to the bottom of the furnace, burning and forming coke. If not handled promptly, this coke can form large clumps that block the furnace. Hot pan furnaces, because the rotating furnace plate at the bottom of the furnace chamber drives the material into the decomposition furnace, and because the furnace speed is adjustable (i.e., the combustion time is adjustable), alternative fuels or hazardous waste combustibles burn more completely, having a relatively smaller impact on the cement production line's process conditions. However, coking is still unavoidable. In stepped furnaces, material falling onto the furnace is propelled forward by a high-pressure airflow from an air cannon. If the material burns quickly, it easily cokes on the furnace bed. Once coked, the air cannon cannot move the material forward, quickly causing furnace blockage. Meanwhile, the combustion-supporting gas flow and the material flow are in the same direction. Due to the characteristics of the material, solid materials tend to sink to the bottom and cannot fully contact the combustion-supporting gas flow, resulting in low combustion efficiency of alternative fuels.

[0004] In summary, existing technologies, due to their inherent structure and combustion heat release methods, result in incomplete combustion and are prone to coking, affecting the normal operation of the equipment. Utility Model Content

[0005] The main purpose of this utility model is to provide a special combustion furnace for fuel substitution in cement plants, which solves the technical problems of insufficient combustion and easy coking in existing combustion furnaces.

[0006] The first aspect of this utility model provides a special combustion furnace for fuel substitution in cement plants, including a furnace cavity, the top of which is an air outlet connected to a decomposition furnace; the bottom is an air inlet from one side connected to a tertiary air duct; a substitute fuel inlet is provided on one side of the top of the furnace cavity; a plurality of material dispersing mechanisms are provided in the furnace cavity between the substitute fuel inlet and the air inlet; the substitute fuel is heated and burned by the tertiary air coming from the opposite direction as it falls in the furnace cavity.

[0007] In a further improvement, a portion of the ash from the combustion of the alternative fuel enters the rotary kiln, while the other portion enters the decomposition furnace with the hot air.

[0008] As a preferred alternative, all the ash from the combustion of the alternative fuel is fed into the decomposition furnace.

[0009] A further improvement is made to the material dispersing mechanism, which includes a spreading plate installed inside the furnace cavity via a spreading plate shaft. Both ends of the spreading plate shaft protrude from the side walls of the furnace cavity and are supported by a support structure mounted on the side walls. An adjustment and fixing mechanism is used to adjust and fix the angle of the spreading plate; this mechanism can be located at one end of the material dispersing mechanism or at both ends.

[0010] In a further improvement, the adjustment and fixing mechanism includes a dial fixed to the outer wall of the furnace cavity and a rocker arm fixedly connected to the exposed end of the spreading plate shaft. The other end of the rocker arm rests on the dial to indicate the angle of rotation.

[0011] A further improvement is made to the dial, which has an arc-shaped array of through holes. A spring-loaded telescopic pin is provided at one end of the rocker arm, and the spring-loaded telescopic pin cooperates with the through holes to fix the position of the rocker arm. When the spring-loaded telescopic pin is pulled up, the rocker arm can be rotated to the desired scale position; when the spring-loaded telescopic pin is released so that it passes through the corresponding through hole, the angle of the spreading plate is adjusted and fixed.

[0012] A further improvement is made to the support structure, which includes a bearing, a support base, a bearing sleeve, and an end cap. The support base and the bearing sleeve are fastened together with bolts. The support base has a receiving space, and a sealing structure is installed in the receiving space. Since the support base and bearing sleeve are detachable, maintenance of the sealing structure is convenient.

[0013] In a further improvement, the sealing structure includes an annular sealing disc fixed to the outer wall of the furnace cavity, a flexible graphite ring fixed to the inner ring by the annular sealing disc, the flexible graphite ring being fitted around the root of the exposed portion of the spreading plate shaft, and the sealing plate cover being fixedly installed on the outer end of the sealing disc.

[0014] Preferably, the horizontal cross-section of the furnace cavity is square, and the vertical cross-section is bent. There are six material distribution mechanisms.

[0015] The application of the technical solution of this utility model has the following technical effects:

[0016] Compared to existing stepped kilns or hot plate kilns, this invention can buffer the falling speed of the alternative fuel and disperse the material, allowing it to be fully and evenly distributed within the combustion chamber. Simultaneously, hot air drawn from the tertiary air duct enters the combustion chamber from one side of the bottom. The upper part of the combustion chamber is connected to the decomposition furnace. Driven by the high-temperature fan of the calcination system, the hot air moves upwards, while the alternative fuel moves downwards, creating opposing flows. During this process, the material is gradually heated and then combusted, preventing ash accumulation and coking. In short, there are two influencing factors: firstly, the relative movement of the alternative fuel and the tertiary air, along with the function of the spreading plate, ensures more complete combustion and less ash; secondly, the design of the furnace chamber structure allows ash to enter the rotary kiln promptly, preventing ash accumulation and coking within the furnace chamber. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0018] Figure 1 The front view of the special combustion furnace for cement plant fuel substitution of this utility model is shown;

[0019] Figure 2 A side view of the special combustion furnace for fuel substitution in cement plants according to this utility model is shown;

[0020] Figure 3 It shows Figure 1 Enlarged view of a portion of point A in the middle.

[0021] The above figures include the following reference numerals:

[0022] 1. Shell;

[0023] 2. Fire-resistant and heat-insulating layer;

[0024] 3. Bulk material handling mechanism;

[0025] 31. Spreading plate;

[0026] 32. Spreading plate shaft;

[0027] 4. Adjust the fixing mechanism;

[0028] 41. Dial;

[0029] 42. Rocker arm;

[0030] 43. Spring telescopic pin;

[0031] 5. Supporting structure;

[0032] 51. Bearing;

[0033] 52. Support base;

[0034] 53. Bearing sleeve;

[0035] 6. Sealed structure;

[0036] 61. Sealing disc;

[0037] 62. Flexible graphite ring;

[0038] 63. Sealing plate cover. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Example

[0040] The first embodiment of this utility model provides a special combustion furnace for fuel substitution in cement plants, including a furnace cavity. The top of the furnace cavity is an air outlet for connecting to a decomposition furnace, and the bottom of the furnace cavity is an air inlet for connecting to a tertiary air duct to provide hot air to the furnace cavity.

[0041] An alternative fuel inlet is provided on one side of the top of the furnace cavity; inside the furnace cavity, several material dispersing mechanisms are provided between the alternative fuel inlet and the air inlet.

[0042] The alternative fuel enters the combustion furnace through the feed pipe. The combustion furnace is equipped with six-stage spreading plates to buffer the falling speed of the alternative fuel and disperse the material, ensuring its even distribution within the combustion furnace space. Simultaneously, hot air drawn from the tertiary air duct enters the combustion furnace from one side of the bottom. The upper part of the combustion furnace chamber is connected to the decomposition furnace. Driven by the high-temperature fan of the calcination system, the hot air moves upwards, while the alternative fuel moves downwards, creating opposing flows. During this process, the material is gradually heated and then combusted.

[0043] In this process, the heat exchange effect is excellent due to the counter-current flow heat exchange, and the material falling speed can also be effectively controlled due to the design of the spreading plate, thereby controlling the combustion time to achieve the effect of complete combustion of the material.

[0044] Under normal circumstances, after the alternative fuel is burned, the heavier ash falls and enters the rotary kiln from the bottom of the combustion furnace, while the lighter ash is carried by the hot air into the decomposition furnace. Because the falling ash after combustion can be guided into the rotary kiln, ash accumulation and coking are avoided.

[0045] Under ideal conditions, alternative fuels such as sawdust or other fully dried and pulverized alternative fuels are used. These can burn completely, producing less and lighter ash, which can all enter the decomposition furnace, thus completely avoiding the problem of coking.

[0046] The following section further describes the specific structure of the dedicated combustion furnace for fuel substitution in cement plants.

[0047] like Figure 1-2 As shown, the furnace cavity has a shell 1 as the outer cavity wall, and an inner cavity wall made of a refractory insulation layer 2, which is fixed to the shell 1. The refractory insulation layer 2 can be a single-layer structure or a composite layer structure to achieve the effect of heat preservation and resistance to internal high temperatures.

[0048] The material distribution mechanism 3 includes a material spreading plate 31, which is installed inside the furnace cavity via a material spreading plate shaft 32. The shaft end of the material spreading plate shaft 32 is supported by a support structure 5 and connected to an adjustment and fixing mechanism 4.

[0049] The adjusting and fixing mechanism 4 includes a scale 41 fixed to the outer wall of the furnace cavity and a rocker arm 42 fixedly connected to the exposed end of the material spreading plate shaft 32. The other end of the rocker arm 42 is projected onto the scale 41 to indicate the rotation angle. The scale 41 has arc-shaped through holes. A spring telescopic pin 43 is provided at the end of the rocker arm that rests on the scale and engages with the through holes to fix the position of the rocker arm. In use, the spring telescopic pin 43 is pulled up, the rocker arm 42 is rotated to the desired scale position, and the spring telescopic pin 43 is released to allow it to pass through the corresponding through hole, thus adjusting and fixing the angle of the material spreading plate 31.

[0050] like Figure 3 As shown, the support structure 5 includes a bearing 51, a support seat 52, a bearing sleeve 53, and an end cap. The support seat 52 and the bearing sleeve 53 are fastened together with bolts. The support seat 52 has a receiving space for installing the sealing structure 6.

[0051] The aforementioned sealing structure 6 is installed at both ends of the material spreading plate shaft 32, where it protrudes from the side wall of the cavity. The sealing structure 6 includes an annular sealing disc 61 fixed to the outer wall of the furnace cavity, and a flexible graphite ring 62 fixed to the inner ring by the annular sealing disc 61. The flexible graphite ring 62 is fitted around the root of the exposed portion of the material spreading plate shaft 32. A sealing plate cover 63 is fixedly installed at the outer end of the sealing disc 61. The core component that performs the sealing function is the flexible graphite ring 62.

[0052] The combination of the above-mentioned support structure 5 and sealing structure 6, with the support seat 52 and bearing sleeve 53 being detachable, facilitates the maintenance of the sealing structure 6.

[0053] In this embodiment, the horizontal cross-section of the furnace cavity is square, and the vertical cross-section is bent. Example

[0054] The second embodiment of this utility model provides a fuel substitution method for cement plants based on the combustion furnace in Embodiment 1. In this method, the substitute fuel falls downwards within the furnace chamber, forming a relative flow with the upward-flowing hot air. After heat exchange and combustion, the heat of the hot air is further increased before entering the decomposition furnace. The ash from the combustion of the substitute fuel falls and can enter the rotary kiln from the bottom of the combustion furnace. Because the falling ash after combustion can be guided into the rotary kiln, ash accumulation and coking are avoided.

[0055] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dedicated combustion furnace for fuel substitution in cement plants, comprising a furnace chamber, characterized in that: The top of the furnace cavity is an air outlet connected to the decomposition furnace; the bottom of the furnace cavity has an air inlet connected to the tertiary air duct. An alternative fuel inlet is provided on one side of the top of the furnace cavity; several material dispersing mechanisms are provided inside the furnace cavity between the alternative fuel inlet and the air inlet. As the alternative fuel falls within the furnace chamber, it is heated and burned by tertiary air from the opposite direction, i.e., from bottom to top.

2. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 1, wherein, A portion of the ash from the combustion of alternative fuels enters the rotary kiln, while the other portion enters the decomposition furnace with the hot air.

3. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 1, wherein, All the ash from the combustion of alternative fuels enters the decomposition furnace.

4. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 1, wherein, The material distribution mechanism includes a material spreading plate, which is installed inside the furnace cavity via a material spreading plate shaft; both ends of the material spreading plate shaft protrude from the side wall of the furnace cavity and are supported by a support structure installed on the side wall; one or both ends of the material spreading plate shaft are connected to an adjustment and fixing mechanism.

5. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 4, wherein, The adjustment and fixing mechanism includes a scale plate fixed to the outer wall of the furnace cavity and a rocker arm fixedly connected to the exposed end of the spreading plate shaft. The other end of the rocker arm rests on the scale plate to indicate the angle of rotation.

6. The fuel replacement special combustion furnace for cement plant as claimed in claim 5 wherein, The dial has through holes arranged in an arc-shaped array, and a spring telescopic pin is provided at one end of the rocker arm. The spring telescopic pin cooperates with the through holes to fix the position of the rocker arm.

7. The fuel replacement special combustion furnace for cement plant as claimed in claim 4 wherein, The support structure includes a bearing, a support seat, a bearing sleeve (53), and an end cap; the support seat and the bearing sleeve are fastened together by bolts; the support seat has a receiving space, and a sealing structure is installed in the receiving space.

8. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 7, wherein, The sealing structure includes an annular sealing disc fixed to the outer wall of the furnace cavity, a flexible graphite ring fixed to the inner ring by the annular sealing disc, the flexible graphite ring being fitted around the root of the exposed portion of the spreading plate shaft, and a sealing plate cover being fixedly installed on the outer end of the sealing disc.

9. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 1, wherein, The furnace cavity has a square horizontal cross-section and a bent vertical cross-section, and there are six material dispersing mechanisms.

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