Combustion furnace special for cement plant fuel replacement and fuel replacement method

Abstract

The invention 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 cavity, and an air outlet is formed in the top of the furnace cavity and 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 the 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] The present invention relates to the technical field of cement production fuel substitution, and in particular to a special combustion furnace and a fuel substitution method for burning alternative fuels or alternative combustion materials with calorific value such as hazardous waste in a cement plant. Background Art

[0002] The cement industry is a high-energy-consuming and high-emission industry. In the process of manufacturing cement clinker, a large amount of coal and other fossil fuels are consumed, and a large amount of waste gas is also discharged into the atmosphere, such as carbon dioxide, sulfur dioxide and nitrogen oxides. At present, about 35% of the carbon emissions in the cement industry are fossil energy emissions, mainly produced by burning coal.

[0003] The existing alternative fuel technology for cement production generally adopts hot plate furnace or step furnace technology. The alternative fuel burns in the furnace, and the hot gas generated by the combustion enters the decomposition furnace to replace part of the heat generated by the coal powder. In this type of combustion furnace, the hot air and the material enter the combustion furnace in the same direction, heating the fuel and then releasing heat. The combustion efficiency is poor, and the material is easy to fall to the bottom of the furnace and burn to form coke. If it is not handled in time, it will form large blocks and block the combustion furnace. For example, since the hot plate furnace drives the material into the decomposition furnace by the rotation of the furnace plate at the bottom of the furnace cavity, the speed of the hot plate furnace can be adjusted, that is, the combustion time can be adjusted, so the alternative fuel or combustible materials such as hazardous waste are relatively fully burned, and the impact of entering the decomposition furnace on the process conditions of the cement production line is relatively small, but coking is also inevitable. For the step furnace, the material falls on the step furnace and is driven forward by the high-pressure airflow from the air cannon. If the material burns faster, it is easy to coke on the furnace bed. After coking, the air cannon cannot move the material forward, and then the combustion furnace will soon be blocked. At the same time, the combustion-supporting gas flow is in the same direction as the material flow. Due to the characteristics of the material, the solid material tends to sink to the bottom and cannot fully contact with the combustion-supporting gas flow, resulting in a lower combustion efficiency of the alternative fuel.

[0004] In summary, the prior art, due to its own structure and combustion heat release mode, leads to incomplete combustion and easily produces coking, thus affecting the normal operation of the equipment. Summary of the invention

[0005] The main purpose of the present invention is to provide a special combustion furnace for cement plant fuel substitution, so as to solve the technical problems that the existing combustion furnaces have insufficient combustion and are prone to coking.

[0006] The first aspect of the present invention provides a special combustion furnace for fuel substitution in a cement plant, comprising a furnace chamber, the top of the furnace chamber being an air outlet connected to a decomposition furnace; the bottom being provided with air intake from one side and connected to a tertiary air duct; an alternative fuel inlet being arranged on one side of the top of the furnace chamber; a plurality of bulk material mechanisms being arranged in the furnace chamber between the alternative fuel inlet and the air inlet; the alternative fuel being heated and burned by the tertiary air coming from the opposite direction during its falling process in the furnace chamber.

[0007] As a further improvement, part of the ash after the combustion of the alternative fuel enters the rotary furnace, and the other part enters the decomposition furnace with the hot air.

[0008] As a preferred alternative, all the ash after combustion of the alternative fuel enters the calciner.

[0009] As a further improvement, the material spreading mechanism comprises a material spreading plate, which is installed in the furnace cavity via a material spreading plate shaft; both ends of the material spreading plate shaft are exposed from the side wall of the furnace cavity and are supported by a support structure installed on the side wall. The adjusting and fixing mechanism is used to adjust and fix the angle of the material spreading plate, and can be set at one end of the material spreading mechanism, or at both ends of the material spreading mechanism.

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

[0011] As a further improvement, the scale plate has through holes arranged in an arc array, and a spring telescopic pin is provided at one end of the rocker arm, and the spring telescopic pin cooperates with the through hole to fix the position of the rocker arm. When the spring telescopic pin is pulled up, the rocker arm can be rotated to the position of the desired scale; when the spring telescopic pin is released to allow it to penetrate into the corresponding through hole, the angle of the spreading plate is adjusted and fixed.

[0012] As a further improvement, the support structure includes a bearing, a supporting seat, a bearing sleeve, and an end cover; the supporting seat and the bearing sleeve are fastened together by bolts; the supporting seat has a receiving space, and the receiving space is equipped with a sealing structure. Since the supporting seat and the bearing sleeve are detachable, the maintenance of the sealing structure is convenient.

[0013] As a further improvement, the sealing structure includes an annular sealing disk fixed to the outer wall of the furnace chamber, a flexible graphite ring fixed to the inner ring by the annular sealing disk, the flexible graphite ring is sleeved on the root of the exposed part of the spreading plate shaft, and the sealing plate cover is fixedly installed on the outer end of the sealing disk.

[0014] Preferably, the horizontal cross section of the furnace chamber is square, and the vertical cross section is bent. There are six bulking mechanisms.

[0015] The second aspect of the present invention provides a cement plant fuel substitution method, using the above-mentioned combustion furnace, the combustion process of the alternative fuel is as follows: the alternative fuel falls downward in the furnace chamber, forms a relative flow with the hot air from the bottom to the top, and after heat exchange combustion, the heat of the hot air is further increased before entering the decomposition furnace. Ash after the alternative fuel is burned falls and can enter the rotary kiln from the bottom of the combustion furnace. Since the falling ash after combustion can be introduced into the rotary kiln, the accumulation of ash to form coke is avoided.

[0016] The application of the technical solution of the present invention has the following technical effects:

[0017] Compared with the existing stepped furnace or hot plate furnace, the present invention can buffer the falling speed of the alternative fuel and break up the materials so that the materials can be fully and evenly distributed in the combustion furnace space. At the same time, the hot air drawn from the tertiary air duct enters the combustion furnace from one side of the bottom of the combustion furnace. The upper part of the combustion furnace cavity is connected to the decomposition furnace. Driven by the pulling force of the high-temperature fan of the firing system, the hot air moves from bottom to top and the alternative fuel moves from top to bottom, forming a counter-flow. In this process, the materials are gradually heated and then burned, and the accumulation of ash to form coke is avoided. In short, there are two influencing factors. One is that the relative movement mode of the alternative fuel and the tertiary air and the role of the scattering plate make the combustion more complete and the ash less. At the same time, the other aspect is that the design of the furnace cavity structure of the present invention can make the ash enter the rotary kiln in time, avoiding the accumulation of ash in the furnace cavity and the accumulation of coke. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A front view of a special combustion furnace for cement plant fuel substitution according to the present invention is shown;

[0020] Figure 2 A side view of the special combustion furnace for fuel substitution in a cement plant according to the present invention is shown;

[0021] Figure 3 Shows Figure 1 A partial enlarged view of point A in the middle.

[0022] The above drawings include the following reference numerals:

[0023] 1. Shell;

[0024] 2. Fire-resistant insulation layer;

[0025] 3. Bulk material mechanism;

[0026] 31. Spreading plate;

[0027] 32. Spreader plate shaft;

[0028] 4. Adjust the fixing mechanism;

[0029] 41. Dial;

[0030] 42. Rocker arm;

[0031] 43. Spring retractable pin;

[0032] 5. Support structure;

[0033] 51. Bearings;

[0034] 52. Support seat;

[0035] 53. Bearing sleeve;

[0036] 6. Sealing structure;

[0037] 61. Sealing plate;

[0038] 62. Flexible graphite ring;

[0039] 63. Seal the plate cover. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] Example 1

[0042] The first embodiment of the present invention provides a special combustion furnace for cement plant fuel substitution, including a furnace cavity, the top of the furnace cavity is an air outlet for connecting to a decomposition furnace; 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.

[0043] An alternative fuel inlet is arranged on one side of the top of the furnace cavity; the furnace is inside the cavity, and a plurality of bulking mechanisms are arranged between the alternative fuel inlet and the air inlet.

[0044] The alternative fuel enters the combustion furnace from the feed pipe, and a six-level spreading plate is designed in the combustion furnace to buffer the falling speed of the alternative fuel and scatter the materials so that the materials can be fully and evenly distributed in the combustion furnace space. At the same time, the hot air from the tertiary air duct enters the combustion furnace from the bottom side of the combustion furnace. The upper part of the combustion furnace cavity is connected to the decomposition furnace. Driven by the pulling force of the high-temperature fan of the firing system, the hot air moves from bottom to top and the alternative fuel moves from top to bottom, forming a counter-flow. In this process, the material is gradually heated and then burned.

[0045] In this process, due to the counter-current heat exchange, the heat exchange effect is good, and due to the design of the spreading plate, the falling speed of the material can also be effectively controlled, thereby controlling the combustion time to achieve the effect of full combustion of the material.

[0046] In general, after the alternative fuel is burned, the heavier ash falls down and enters the rotary kiln from the bottom of the combustion furnace, and the lighter ash follows the hot air into the decomposition furnace. Since the falling ash after combustion can be introduced into the rotary kiln, the accumulation of ash to form coke is avoided.

[0047] Under good circumstances, the alternative fuel is powdered fuel such as sawdust, or other alternative fuels that have been fully dried and crushed. This type of fuel can be fully burned, producing less and lighter ash, which can all enter the decomposition furnace, thus completely avoiding the coking problem.

[0048] The specific structure of the special combustion furnace for fuel substitution in cement plants is further introduced below.

[0049] like Figure 1-2 As shown, the furnace cavity has a shell 1 as an outer cavity wall, and the inner cavity wall adopts a fire-resistant heat-insulating layer 2, which is fixed to the shell 1. The fire-resistant heat-insulating 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 temperature.

[0050] The material dispersing mechanism 3 comprises a material spreading plate 31 , which is installed in the furnace cavity via a material spreading plate shaft 32 . The shaft end of the material spreading plate shaft 32 is supported by a supporting structure 5 and connected to the adjusting and fixing mechanism 4 .

[0051] The adjustment and fixing mechanism 4 includes a dial 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 falls on the dial 41 to indicate the rotation angle. The dial 41 has through holes arranged in an arc shape. A spring telescopic pin 43 is provided at one end of the dial where the rocker arm falls to cooperate with the through hole to fix the position of the rocker arm. When in use, pull up the spring telescopic pin 43, rotate the rocker arm 42 to the position of the desired scale, release the spring telescopic pin 43 to make it penetrate into the corresponding through hole, complete the adjustment of the angle of the material spreading plate 31, and fix it.

[0052] like Figure 3 As shown, the support structure 5 includes a bearing 51, and a support seat 52, a bearing sleeve 53, and an end cover provided for the bearing 51. The support seat 52 and the bearing sleeve 53 are fastened together by bolts. The support seat 52 has a receiving space, and the receiving space is used to install the sealing structure 6.

[0053] The above-mentioned sealing structure 6 is arranged at the positions where both ends of the material spreading plate shaft 32 are exposed from the side wall of the cavity. The sealing structure 6 comprises an annular sealing disc 61 fixed to the outer wall of the furnace cavity, a flexible graphite ring 62 fixed to the inner ring by the annular sealing disc 61, and the flexible graphite ring 62 is sleeved on the root of the exposed part of the material spreading plate shaft 32. The sealing plate cover 63 is fixedly mounted on the outer end of the sealing disc 61. The core element that plays a sealing role is the flexible graphite ring 62.

[0054] The combination of the supporting structure 5 and the sealing structure 6 is convenient for maintenance of the sealing structure 6 because the supporting seat 52 and the bearing sleeve 53 are detachable.

[0055] In this embodiment, the horizontal cross section of the furnace cavity is square, and the vertical cross section is bent.

[0056] Example 2

[0057] The second embodiment of the present invention provides a cement plant fuel substitution method based on the combustion furnace in embodiment 1, in which the alternative fuel falls downward in the furnace chamber, forms a relative flow with the hot air coming from the bottom to the top, and after heat exchange combustion, the heat of the hot air is further increased before entering the decomposition furnace. Ash after the combustion of the alternative fuel falls and can enter the rotary kiln from the bottom of the combustion furnace. Since the falling ash after combustion can be introduced into the rotary kiln, the accumulation of ash to form coke is avoided.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A special combustion furnace for fuel substitution in a cement plant, 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 is provided with 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; a plurality of bulking mechanisms are provided in the furnace cavity between the alternative fuel inlet and the air inlet; When the alternative fuel falls in the furnace cavity, it is heated and burned by the tertiary wind from the opposite direction, that is, from bottom to top.

2. The cement plant fuel replacement special combustion furnace according to claim 1, characterized in that: Part of the ash after the combustion of the alternative fuel enters the rotary furnace, and the other part enters the decomposition furnace with the hot air.

3. The cement plant fuel replacement special combustion furnace according to claim 1, characterized in that: All the ash after burning the alternative fuel enters the decomposition furnace.

4. The cement plant fuel replacement special combustion furnace according to claim 1, characterized in that: The material dispersing mechanism includes a spreading plate, which is installed in the furnace cavity through a spreading plate shaft; both ends of the spreading plate shaft are exposed to the side wall of the furnace cavity and are supported by a supporting structure installed on the side wall; one end or both ends of the spreading plate shaft are connected to an adjusting and fixing mechanism.

5. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 4, characterized in that: The adjusting and fixing mechanism comprises a dial fixed to the outer wall of the furnace chamber and a rocker arm fixedly connected to the exposed end of the spreading plate shaft, and the other end of the rocker arm falls on the dial to indicate the rotation angle.

6. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 5, characterized in that: The scale plate 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 hole to fix the position of the rocker arm.

7. The cement plant fuel replacement dedicated combustion furnace as claimed in claim 4, characterized in that: The support structure includes a bearing, a supporting seat, a bearing sleeve 53, and an end cover; the supporting seat and the bearing sleeve are fastened together by bolts; the supporting seat has a receiving space, and a sealing structure is installed in the receiving space.

8. The cement plant fuel substitution dedicated combustion furnace as claimed in claim 7, characterized in that: The sealing structure includes an annular sealing disk fixed to the outer wall of the furnace chamber, a flexible graphite ring fixed to the inner ring by the annular sealing disk, the flexible graphite ring is sleeved on the root of the exposed part of the spreading plate shaft, and the sealing plate cover is fixedly installed on the outer end of the sealing disk.

9. The special combustion furnace for cement plant fuel substitution as claimed in claim 1, wherein the horizontal cross section of the furnace chamber is square, and the vertical cross section is bent; and there are six bulk material dispersing mechanisms.

10. A method for replacing fuel in a cement plant, characterized in that: Based on the combustion furnace as described in any one of claims 1 to 9, its combustion process is as follows: the alternative fuel falls downward in the furnace chamber, forms a relative flow with the hot air coming from the bottom to the top, and after heat exchange combustion, the heat of the hot air is further increased before entering the decomposition furnace; part of the ash after the combustion of the alternative fuel enters the rotation, and the other part enters the decomposition furnace with the hot air.

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