Prefabricated composite blowing grate plate module, blowing conveying bottom plate and grate type pre-combustion furnace

Abstract

The invention relates to a prefabricated composite injection grate plate module (10), an injection conveying bottom plate (30) and a grate type pre-combustion furnace. The injection grate plate module (10) is composed of a shell (101), a wear-resistant castable (102) and at least two airflow nozzles (103) with outlets inclining upwards. Nozzles of the airflow nozzles (103) are all located on the material receiving face of the blowing grid plate module (10), and the material receiving face is the upper surface of the blowing grid plate module (10). In the material flow direction, the included angle gamma 1 formed by the spraying direction of the nozzle of the airflow nozzle (103) located on the rearmost side and the material receiving face of the blowing grid plate module (10) is 10-35 degrees, and the included angles formed by the spraying directions of the nozzles of the other airflow nozzles (103) and the material receiving face of the blowing grid plate module (10) are equal to the included angle gamma 1 or gradually reduced. The airflow entering the airflow nozzle (103) is obliquely and upwards sprayed out along the material receiving face, and the materials are driven to be upwards sprayed out to form a parabola path to rise and move forwards. According to the device, the problems of incomplete combustion, working condition fluctuation, crust blockage, NOx standard exceeding and the like caused by fossil fuel used by a sintering system can be reduced, and the purposes of increasing the use ratio of alternative fuel, stabilizing the thermal regulation of a kiln and realizing ultralow emission of the system are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial production, and in particular relates to a prefabricated composite injection grate plate module, an injection conveying bottom plate and a grate-type pre-combustion furnace for treating low-grade solid waste fuel. Background Art

[0002] Co-processing solid waste with kilns is a trend in the current green development of industry. Low-calorific-value solid waste, such as biomass, textile waste, and RDF (domestic waste derivatives), has a high moisture content and large two-dimensional dimensions. Pre-processing equipment is generally required to mitigate negative impacts on existing systems and leverage the calorific value of solid waste to reduce fossil fuel use. Typical pre-processing devices, such as hot plate furnaces, rotary kilns, and stepped pre-combustion furnaces, can be used as alternative fuels in kiln systems. The stepped pre-combustion furnace, with its non-moving parts, represents a promising pre-combustion equipment option.

[0003] Chinese patent announcement number CN207661818U discloses a pneumatic transmission base plate for a stepped combustion chamber, which has multiple steps. These steps include nozzles and covering elements made of refractory materials and are installed by specific fastening elements; wherein the gas flow direction guided by the nozzles in the steps is oriented horizontally or tilted downward. In this patent, the ejected gas flows horizontally upward or tilted downward, which has a better forward transmission effect on the transportation of materials and can also prevent the nozzle from being blocked. However, the device has a greater pushing and transmission effect on the material than on the tumbling and stirring of the material, and has limited effect on improving the full contact between the material and the oxygen-containing high-temperature air. At the same time, the cold wind close to the high-temperature receiving surface greatly shortens the life of the refractory material.

[0004] Chinese patent publication number CN218566182U discloses a stepped air box and a pre-combustion furnace having the same. The stepped air box comprises an upper panel and a front panel with a front air outlet; a jet cooling duct and a jet duct are provided inside the shell. This patent provides a good protective effect on the combustion upper platform through the cooling airflow of the upper panel, solving the problem that the stepped platform is easily damaged. However, the effect on the forward transmission of materials is limited, and the mixing disturbance between materials and gases is not solved. In addition, the above patent does not mention how to adopt intelligent control strategies for different working conditions to match the delivery process of alternative fuels with the drying and combustion process.

[0005] In summary, the main problems of the current stepped pre-combustion furnace are:

[0006] 1) The material reaction in the furnace is uneven, and the local sticky and wet waste is seriously agglomerated, unable to fully contact with the oxygen-containing high-temperature air, resulting in a low waste burnout rate, large fluctuations in CO at the decomposition furnace outlet, uncontrollable NOx emissions, and the inability to achieve large-scale waste disposal;

[0007] 2) The high-temperature surface of the material is blown by high-speed cold air, which is prone to cracking; a large amount of liquid phase is produced during combustion, which adheres to the bottom plate and near the nozzle, easily causing blockage and crusting;

[0008] 3) The delivery process of the alternative fuel does not match the drying and combustion process. When the quality of the waste being processed changes or the feed amount fluctuates, corresponding adjustments cannot be made in time. There is a lack of reasonable and intelligent monitoring methods and control strategies to avoid affecting the combustion conditions in the kiln. Summary of the Invention

[0009] In order to solve the technical problems existing in the prior art, the present invention provides a prefabricated composite blowing grate module, a blowing conveying base plate and a grate-type precombustion furnace. Through the structural design of the prefabricated blowing grate module, the gradient material design of the blowing conveying base plate and the intelligent control mode, it can reduce the problems of incomplete combustion, operating condition fluctuations, crusting and blockage, NOx exceeding the standard, etc. caused by the use of fossil fuels in the firing system, thereby achieving the purpose of increasing the proportion of low-grade solid waste alternative fuels, stabilizing the thermal system of the kiln and the ultra-low emissions of the system.

[0010] The present invention is implemented as follows: a prefabricated composite blowing grate module consists of a shell, a wear-resistant castable filled in the shell, and at least two air flow nozzles with outlets inclined upward and embedded in the wear-resistant castable; the nozzles of the air flow nozzles are all located on the receiving surface of the blowing grate module, and the receiving surface of the blowing grate module is the upper surface of the blowing grate module; along the material flow direction, the angle γ1 formed by the ejection direction of the air flow nozzle located on the rear side and the receiving surface of the blowing grate module is 10 to 35 degrees, and the angles formed by the ejection directions of the nozzles of the remaining air flow nozzles and the receiving surface of the blowing grate module are equal to the angle γ1, or gradually decrease; the air flow entering the air flow nozzle is ejected obliquely upward along the receiving surface of the blowing grate module, driving the material to eject upward to form a parabolic path and move forward, thereby increasing the sufficient contact time with the high-temperature air.

[0011] Preferably, the shell and the airflow nozzle are made of heat-resistant steel with a temperature tolerance of 1000-1300°C.

[0012] Preferably, the material receiving surface of the blowing grate module is covered with a high temperature resistant SiC plate.

[0013] Preferably, the cross-section of the airflow nozzle gradually becomes flat and narrow in the transverse direction from the inlet to the nozzle, and the instantaneous speed of the airflow released after the airflow nozzle sprays is supersonic.

[0014] Preferably, each air flow nozzle in each of the blowing grate modules uses the same inlet to supply air, and the air flow supplied by the blowing grate module is high-pressure combustion-supporting air or fuel gas.

[0015] A blowing conveying base plate, which is composed of blowing grate modules arranged in multiple levels in the longitudinal direction and multiple columns in the transverse direction and placed obliquely, and a discharge grate module located at the end of the blowing conveying base plate. The blowing conveying base plate is arranged obliquely downward along the material flow direction. The blowing conveying base plate is divided into three areas along the material flow direction: a preheating section, a combustion section, and a discharge section. The preheating section, the combustion section, and the discharge section are respectively provided with different grate module combinations to form a blowing conveying base plate with a gradient distribution, so as to realize the upward tumbling of the bottom material and the forward transportation of the alternative fuel on the blowing conveying base plate.

[0016] Preferably, the blowing grate module is arranged tilted downward along the material flow direction, with an inclination angle α of 2 to 10°; between two adjacent blowing grate modules, the nozzle of the air flow nozzle located at the rear side along the material flow direction is located at the overlapping intersection of the upper and lower blowing grate modules.

[0017] Preferably, the receiving surface length of a single blowing grate module in the preheating section is greater than the receiving surface length of a single blowing grate module in the combustion section, the preheating section is provided with 1 to 3 levels of blowing grate modules, and the preheating section angle β1 is 15 to 28°; the combustion section is provided with 2 to 6 levels of blowing grate modules, and the combustion section angle β2 is 28 to 35°; the discharging section is provided with 1 to 2 levels of discharging grate modules, and the discharging section angle β3 is 45 to 60°; and β1﹤β2﹤β3.

[0018] A grate-type pre-combustion furnace for processing alternative fuels comprises a combustion chamber and a blowing and conveying base plate, wherein the blowing and conveying base plate is located at the bottom of the combustion chamber, and the discharge grate plate module of the blowing and conveying base plate extends into the combustion furnace. The combustion chamber is provided with an alternative fuel inlet, a high-temperature air inlet and a sand inlet. An alternative fuel inlet and a high-temperature air inlet are provided at one end of the combustion chamber, and the high-temperature air inlet is connected to a high-temperature air inlet pipe. The other end of the combustion chamber is connected to the combustion furnace, and the sand inlet is located at the dome of the combustion chamber and / or the high-temperature air inlet.

[0019] Preferably, the sand material is a calcium-based mineral material.

[0020] Preferably, the top of the combustion chamber is provided with a plurality of temperature measuring points for monitoring temperature distribution and a high-temperature camera for monitoring combustion status, and the outlet of the combustion chamber is provided with a gas composition measuring point for monitoring outlet gas composition.

[0021] Preferably, the alternative fuel inlet is located at the high-temperature air inlet and / or below the high-temperature air inlet; when located at the high-temperature air inlet, a scattering box is provided at the alternative fuel inlet, and the alternative fuel is scattered into the high-temperature air inlet pipe by the scattering box and fed into the combustion chamber together with the high-temperature air; when located below the high-temperature air inlet, an alternative fuel feeding device is provided at the alternative fuel inlet, and the alternative fuel is fed into the combustion chamber by the alternative fuel feeding device.

[0022] Preferably, the blowing working mode of the blowing conveying bottom plate is in accordance with the small cycle of traversing the entire column, and the two adjacent blowings of the blowing grate modules at different levels are separated by at least one step, and the order of the blowing of each level is from the low temperature zone to the high temperature zone in sequence according to the dome temperature monitoring data. The blowing grate modules at the same level adopt non-adjacent blowing to prevent the material from entering the grate gap formed by the nozzles of the blowing grate modules in adjacent columns, and finally the setting is based on the principle of traversing all the blowing grate modules.

[0023] The operating frequency of the injection grate module is calculated based on the average temperature of multiple temperature measurement points on the top of the combustion chamber. The formula is as follows:

[0024]

[0025] Among them, T avg is the average temperature of multiple points, in degrees; τintel is the interval between two adjacent injections, in seconds.

[0026] The present invention fully considers the drawbacks of existing equipment, optimizes the structure of the prefabricated blowing grate module, the design of the gradient material distribution of the blowing conveying base plate, and the blowing method, and uses high-speed gas to blow the material upward, so that the material falls in a parabolic path, increases the contact time between the waste and the high-temperature air flow, strengthens the drying, cracking and combustion speed of the waste, and accelerates the effective utilization of the entire waste. At the same time, the structure of the blowing grate module itself is prefabricated to protect the air blowing outlet, avoid crusting blockage and material leakage, reduce the spalling of refractory materials near the blowing outlet due to thermal shock, extend the service life of the refractory materials, and improve the effective operation rate of the pre-combustion furnace. In addition, the conveying base plate composed of the blowing grate module adopts an intelligent control mode, which can adapt to the controllable, sufficient and reliable use of more alternative fuels of different qualities, reducing the adaptation ratio of fossil fuels.

[0027] The present invention solves the problems of insufficient local ventilation and reaction process control in the pre-combustion furnace, fully utilizes the high-temperature air of the firing system for pre-combustion, returns the heat released by the alternative fuel reaction to the firing system, and reduces the burden of the firing system on directly processing large-scale solid waste. It can not only achieve the harmless disposal of large amounts of solid waste, but also realize the energy substitution of fossil fuels, thereby achieving the purpose of energy saving and carbon reduction.

[0028] The advantages and positive effects of the present invention are:

[0029] 1. In response to the limitations of existing stepped pre-calcining devices, the present invention proposes a blowing and conveying base plate that effectively solves the problem of uniform ventilation and sufficient pre-calcination of piled and agglomerated alternative fuels. It can control the reaction process of cracking, gasification and subsequent combustion of alternative fuels, thereby solving the problems of incomplete combustion, crusting and blockage, large fluctuations in thermal system, and uncontrollable NOx emissions caused by the treatment of alternative fuels in the firing system, thereby overcoming the bottleneck of difficulty in increasing the replacement ratio.

[0030] 2. The prefabricated injection grate module of the present invention includes at least two upwardly angled supersonic airflow nozzles, which respectively serve to flip and blow the material. This allows the alternative fuel on the receiving surface to be ejected upward and forward at high speed, transporting the alternative fuel forward and creating air disturbance at the bottom of the material layer, particularly at the base of the injection grate module, where it is less exposed to air. This increases contact between the alternative fuel and the high-temperature, oxygen-containing air, enhancing its combustion. The receiving surface of the injection grate module is designed with varying lengths along the material flow direction, resulting in a gradient distribution design for the injection conveying baseplate. This allows for the movement and transmission of the alternative fuel and controls its combustion rate, avoiding the two extremes of incomplete local combustion and overheating.

[0031] 3. The working gap of each blowing grate module in the blowing conveying bottom plate of the present invention is set with an intelligent control mode. The average temperature obtained by measuring the top of the combustion chamber can intelligently adjust the working gap of each blowing grate module to control the residence time and reaction process of the alternative fuel, which is beneficial to improving the burnout rate of the alternative fuel in the firing system and has a wider applicability for alternative fuels with unstable quality.

[0032] 4. The grate-type pre-combustion furnace of the present invention is suitable for ventilation and conveying sticky and wet materials such as alternative fuels. The spray conveying base plate is assembled and arranged using prefabricated spray grate modules. It features an upwardly inclined supersonic spray airflow and a gradient distribution. This causes the sticky and wet materials on the spray conveying base plate to rise upward and forward in a parabolic trajectory, simultaneously controlling the ventilation disturbance of the materials at the bottom of the alternative fuel layer and achieving the effect of continuous forward conveyance. In addition, the special channel design and upward outlet angle design of the airflow nozzle avoid the stimulation of the sudden cooling and heating of the refractory materials on the receiving surface by the incoming cold air, effectively protecting the life of the refractory materials of the spray grate plate. Combined with the intelligent spraying program, it can effectively prevent the sticky and wet alternative fuel from clogging the channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of the prefabricated composite blowing grate module provided in an embodiment of the present invention;

[0034] Figure 21 is a top view of a prefabricated composite blowing grate module provided in an embodiment of the present invention;

[0035] Figure 3 2. It is a structural schematic diagram of a spray conveying bottom plate provided by an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of the arrangement of the blowing conveying bottom plate provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of the grate type pre-combustion furnace provided by the embodiment of the present invention. Figure 1 ;

[0038] Figure 6 This is a schematic diagram of the structure of the grate type pre-combustion furnace provided by the embodiment of the present invention. Figure 2 .

[0039] In the figure, 10, blowing grate module; 101, shell; 102, wear-resistant castable; 103, air flow nozzle; 104, high temperature resistant SiC plate;

[0040] 20. Discharge grate module;

[0041] 30. Blowing conveying bottom plate; 301. Preheating section; 302. Combustion section; 303. Discharging section;

[0042] 40. Combustion chamber; 401. Alternative fuel inlet; 4011. Alternative fuel feed device; 4012. Spreading box; 402. High-temperature air inlet; 4021. High-temperature air inlet pipe; 4022. High-temperature air inlet louver valve; 403. Abrasive inlet 1; 4031. Abrasive feed flap valve 1; 403a. Abrasive inlet 2; 4031a. Abrasive feed flap valve 2;

[0043] 50. Combustion furnace. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. It is obvious that the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] The embodiment of the present invention provides a prefabricated composite blowing grate module, such as Figure 1 and Figure 2As shown, it consists of a shell 101, a wear-resistant castable 102 with good thermal shock stability filled in the shell, and at least two air flow nozzles 103 with outlets inclined upwards embedded in the wear-resistant castable. The nozzles of the air flow nozzles 103 are all located on the receiving surface of the blowing grate module. The receiving surface of the blowing grate module is the upper surface of the blowing grate module, and the receiving surface of the blowing grate module is covered with a high-temperature resistant SiC plate 104. Specifically, in this embodiment, the outside of the blowing grate module is a shell 101, and the inside of the shell 101 is filled with a wear-resistant castable 102 with good thermal shock stability. Two air flow nozzles 103 are embedded in the wear-resistant castable 102, and the receiving surface is covered with a high-temperature resistant SiC plate 104. The material of the shell 101 and the air flow nozzle 103 are both heat-resistant steel, with a temperature resistance of 1000 to 1300°C.

[0046] The blowing grate module adopts two air flow nozzles 103 that spray upward along the receiving surface. The air flow sprayed by the air flow nozzles 103 is sprayed upward at a certain angle to the horizontal direction, so that the sprayed material moves upward and forward in a parabolic path. Specifically, along the material flow direction, the angle γ1 formed by the spraying direction of the nozzle of the air flow nozzle located on the rear side and the material receiving surface of the blowing grate module is 10~35°, and the nozzle of this air flow nozzle is located at the overlapping intersection of the two-stage blowing grate modules, and the oblique upward spray plays the role of turning the material; the angle γ2 formed by the spraying direction of the nozzle of the air flow nozzle located on the front side and the material receiving surface of the blowing grate module is 5~30°, and the nozzle of this air flow nozzle is located in the middle of the blowing grate module, which plays the role of forward transportation and cooling the blowing grate module; and γ1≥γ2, the two air flow nozzles work together to make the air flow entering the air flow nozzle spray obliquely upward along the material receiving surface of the blowing grate module, driving the material to spray upward to form a parabolic path and move forward, which can achieve a better blowing effect and increase the sufficient contact time with high-temperature air.

[0047] The air flow nozzles near the junction of the two-stage blowing grate modules have a larger blowing angle to ensure that the material layer in the corners that are not easily exposed to air and prone to forming dead material areas rises higher, thereby increasing the contact time between the alternative fuel and the high-temperature air; the air flow nozzles near the middle of the receiving surface have a slightly smaller blowing angle, so that some of the reacted alternative fuel on the steps is transported forward.

[0048] The blowing grate module can adjust the spraying angle γ of the blowing grate module and the pressure of the air source of the air flow nozzle according to the bulk density of the alternative fuel to control the appropriate forward movement speed of the alternative fuel.

[0049] The airflow nozzle 103 gradually narrows in cross-section from the inlet to the nozzle, and the instantaneous velocity of the airflow released after the airflow nozzle is supersonic. The airflow nozzle has a circular inlet and gradually narrows toward the outlet, which prevents large pieces of fuel from entering the grate formed by the nozzle. At the same time, after being ejected through the narrow pipe by the airflow nozzle, the airflow is instantly released at an instantaneous velocity of supersonic speed, achieving a higher energy acceleration effect.

[0050] The two air flow nozzles in each of the blowing grate modules use the same inlet to supply air. The air flow supplied by the blowing grate module is high-pressure combustion air or fuel gas. The instantaneous speed released after being sprayed by the air flow nozzle can reach supersonic speed, which has a higher energy acceleration effect.

[0051] A blowing conveying bottom plate, such as Figure 3 and Figure 4 As shown, the blowing conveying base plate is composed of a blowing grate module 10 arranged in multiple levels in the longitudinal direction and multiple columns in the transverse direction and placed obliquely, and a discharge grate module 20 located at the end of the blowing conveying base plate. The blowing conveying base plate is arranged obliquely downward in the direction of the material flow. The blowing conveying base plate is divided into three zones along the material flow direction according to the material combustion conditions: a preheating section 301, a combustion section 302, and a discharge section 303 in sequence. The preheating section, the combustion section, and the discharge section are respectively provided with different grate module combinations according to different combustion characteristics to form a blowing conveying base plate with a gradient distribution, so as to achieve the effect of the bottom material rising and rolling and the alternative fuel on the blowing conveying base plate being transported forward.

[0052] The blowing grate module 10 is arranged tilted downward along the material flow direction, with an inclination angle α of 2 to 10°; between two adjacent blowing grate modules, the nozzle of the air flow nozzle located at the rear side along the material flow direction is located at the overlapping intersection of the upper and lower blowing grate modules.

[0053] According to the different expected residence times of the three zones, the receiving surface length of a single blowing grate module in the preheating section 301 is greater than the receiving surface length of a single blowing grate module in the combustion section 302. Ultimately, the angles of the three zones of the receiving surface of the entire blowing conveying bottom plate are different: the preheating section 301 is equipped with 1 to 3 levels of blowing grate modules, and the preheating section angle β1 is 15 to 28 degrees; the combustion section 302 is equipped with 2 to 6 levels of blowing grate modules, and the combustion section angle β2 is 28 to 35 degrees; the discharge section 303 is the bottom step of the grate-type pre-combustion furnace, and is equipped with 1 to 2 levels of discharge grate modules, and the discharge section angle β3 is 45 to 60 degrees; and β1 < β2 < β3. The above gradient distribution method is used as a means of regulating the temperature in the combustion furnace.

[0054] The discharge grate module 20 is composed of a shell and wear-resistant castable filled in the shell. No air flow nozzle is provided in the wear-resistant castable of the discharge grate module.

[0055] Example 1

[0056] like Figure 5 As shown, a grate-type pre-combustion furnace for processing alternative fuels includes a combustion chamber 40 and a jet conveying base plate 30. The jet conveying base plate 30 is located at the bottom of the combustion chamber, and the discharge grate module of the jet conveying base plate extends into the combustion furnace 50. The combustion chamber 40 is provided with an alternative fuel inlet 401, a high-temperature air inlet 402, and multiple sand inlets 403. The alternative fuel inlet 401 and the high-temperature air inlet 402 are provided at one end of the combustion chamber, and the other end of the combustion chamber is connected to the combustion furnace 50. Specifically, the discharge grate module 303 of the discharge section extends into the combustion furnace 50 to discharge the material. The rising airflow in the combustion furnace is more likely to carry unburned materials, which are further burned in the combustion furnace.

[0057] The alternative fuel inlet 401 is located below the high-temperature air inlet 402. An alternative fuel feed device 4011 is provided at the alternative fuel inlet 401, through which the alternative fuel is fed into the combustion chamber 40. The alternative fuel feed device can use a spiral reamer feeding method to push the alternative fuel into the combustion chamber. A high-temperature air inlet pipe 4021 is provided at the high-temperature air inlet 402. The high-temperature air inlet pipe 4021 is connected to the combustion chamber and is equipped with a high-temperature air inlet louver valve 4022. The sand inlet 403 is located at the dome of the combustion chamber and the high-temperature air inlet. Each sand inlet 403 is equipped with a sand feed flap valve 4031.

[0058] The alternative fuel enters through the inlet of the alternative fuel feed device and is pushed into the grate precombustion furnace by a spiral reamer. The high-speed airflow from the nozzles of the grate module disperses and lifts the alternative fuel, transporting it forward to the combustion furnace. Hot air for combustion enters through the high-temperature air inlet 402, with the air volume adjusted by the high-temperature air inlet louver valve 4022 according to the combustion temperature and oxygen content. A sand inlet 1 403 is located in the dome of the combustion chamber, and a sand inlet 2 403a is located on the air intake duct. The amount of sand entering sand inlets 1 403 and 2 403a is controlled by sand feed flap valve 1 4031 and sand feed flap valve 2 4031a. The sand is a calcium-based mineral material that not only controls the temperature within the grate precombustion furnace combustion chamber, reduces agglomeration of the alternative fuel, and facilitates its dispersion and ventilation, but also catalyzes the directional thermal cracking of the alternative fuel products.

[0059] The combustion chamber's top is equipped with multiple temperature measurement points, a high-temperature camera, and a gas composition measurement point at the outlet. Based on the monitored temperature distribution, combustion status, and outlet gas composition, the high-temperature air inlet louver valve 4022, abrasive feed flap valve 1 4031, and abrasive feed flap valve 2 4031a are adjusted to control the high-temperature air inlet volume and abrasive feed volume. Furthermore, the injection mode of the injection conveyor bottom plate is intelligently controlled, thereby intelligently controlling the movement speed and combustion rate of the alternative fuel.

[0060] like Figure 4 As shown, the blowing working mode of the blowing conveying bottom plate is according to the principle of traversing the entire column small cycle (from the 1st column to the nth column small cycle), and the two adjacent blowings of the blowing grate modules at different levels are separated by at least one step, and the order of each level of blowing is from the low temperature zone to the high temperature zone in sequence according to the dome temperature monitoring data; the blowing grate modules at the same level adopt non-adjacent blowing to prevent the material from entering the grate gap formed by the nozzles of the blowing grate modules in the adjacent columns, and finally the setting is carried out on the principle of traversing all the blowing grate modules.

[0061] The operating frequency of the injection grate module is calculated based on the average temperature of multiple temperature measurement points on the top of the combustion chamber. The formula is as follows:

[0062]

[0063] Among them, T avg is the average temperature of multiple points, in degrees; τ intel It is the interval time between two adjacent injections, in seconds.

[0064] The intelligent control of the blowing working mode of the blowing conveying bottom plate is to obtain the average temperature of multiple positions through multiple temperature monitoring devices (i.e., multiple temperature measuring points) installed on the top of the combustion chamber, and then calculate the working frequency of the blowing grate module through the above formula.

[0065] This embodiment is particularly suitable for the treatment of combustible waste with a moisture content below 20%, such as biomass, pre-treated waste textiles, plastics, RDF, etc.

[0066] Example 2

[0067] The difference from Example 1 is that:

[0068] For some viscous alternative fuels such as waste textiles, municipal solid waste, sludge, etc. whose 3D dimensions are difficult to control and whose moisture content is above 20%, a combination of spiral reamer feeding and high-temperature air inlet pipe feeding can be used to feed the grate pre-combustion furnace. At this time, the sand inlet is located at the dome of the combustion chamber. Figure 6 As shown, the details are as follows:

[0069] After passing through the distribution valve, the alternative fuel is sent into the alternative fuel feeding device 4011 and fed through the spiral reamer. The other way is directly sprinkled into the high-temperature air inlet pipe through the scattering box 4012 set on the high-temperature air inlet pipe 4021 and enters the grate pre-combustion furnace together with the high-temperature air. On the one hand, it can dry part of the moisture in the alternative fuel and replace the sand to adjust the high-temperature air inlet temperature. On the other hand, it can also reduce the pressure of the spiral reamer feeding to avoid the entanglement and crushing of long and high-moisture sticky materials on the spiral reamer.

[0070] For the treatment of high-moisture viscous alternative fuels, the angles γ1 and γ2 formed by the ejection direction of the airflow nozzle of the blowing grate module and the receiving surface of the blowing grate module can be appropriately increased, focusing on the upward loosening and lifting effect of the high-speed airflow, reducing the forward conveying distance, so as to increase the contact time with the high-temperature oxygen-containing air and increase the residence time of the alternative fuel in the pre-combustion furnace.

[0071] When the air flow nozzle of the blowing grate module uses high-speed, high-pressure fuel gas hydrogen to disperse the alternative fuel on the receiving surface, the hydrogen and the alternative fuel are premixed and dispersed in the pre-combustion furnace. By utilizing the fast combustion speed of hydrogen, the non-flammable alternative fuel at the bottom of the pre-combustion furnace is ignited to reach the ignition point, thereby accelerating its combustion process.

[0072] The top of the combustion chamber is equipped with multiple temperature measurement points, a high-temperature camera, and a gas composition measurement point at the outlet. Based on the monitored temperature distribution, combustion status, and outlet gas composition, the high-temperature air inlet louver valve 4022, abrasive feed flap valve 4031, and material distribution box 4012 are adjusted to control the high-temperature air inlet volume, abrasive feed volume, and alternative fuel feed volume at the distribution box. Furthermore, the injection mode and operating frequency of the injection conveying base are intelligently controlled, thereby intelligently controlling the movement speed and combustion speed of the alternative fuel.

[0073] Example 3

[0074] The industrial analysis of the alternative fuels used in Project A is shown in Table 1. Overall, the ash content of textile waste, leather, wood chips, and wood blocks is very low, and the volatile matter is very high. Among them, the calorific value of textile waste is higher, while the calorific value of wood chips and wood blocks is relatively low.

[0075] Table 1A Industrial Analysis of Alternative Fuel Samples Used in Project

[0076]

[0077] Table 2 Thermogravimetric analysis results of alternative fuels used in Project A

[0078]

[0079] Thermogravimetric analysis of all alternative fuel samples from Project A showed that:

[0080] The starting temperature of thermal weight loss of waste textiles is around 316℃ and the ending temperature is around 671℃, and the combustion activity is average;

[0081] The starting temperature of thermal weight loss of leather is around 307℃ and the ending temperature is around 399℃, indicating good combustion activity.

[0082] The starting temperature of thermal weight loss of wood chips is around 271℃ and the ending temperature is around 495℃, indicating good combustion activity.

[0083] The starting temperature of the thermal weight loss of the wood block is around 274℃ and the ending temperature is around 495℃, and the combustion activity is good.

[0084] According to the characteristics of alternative fuels, a pre-combustion furnace structure with a heat replacement of 40% and a feed capacity of 10t / h was further designed. Its injection conveying bottom plate is arranged in 4 rows horizontally and 12 levels vertically (including 1-level preheating section, 10-level combustion section, and 1-level discharge section). The oxygen content in the grate pre-combustion furnace is adjustable, and the cracking and combustion process of the fuel is controlled by regulating the oxygen content. For the alternative fuel with a higher volatile content in Project A, the air equivalence ratio in the pre-combustion furnace can be appropriately reduced. After the initial heat treatment, the alternative fuel stays in the grate pre-combustion furnace for 15 to 20 minutes, and then enters the combustion furnace with the high-temperature flue gas for further thorough combustion. After heat treatment in the grate pre-combustion furnace, not only can the heat utilization rate of the alternative fuel itself be improved, reducing the impact of fluctuations in the kiln conditions of the combustion furnace, but also the adverse effects of the fuel gas discharged from the grate pre-combustion furnace on the pollutant emissions of the combustion furnace are reduced.

[0085] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A prefabricated composite blowing grate module, characterized in that: It consists of a shell, a wear-resistant castable filled in the shell, and at least two air flow nozzles with outlets inclined upward and embedded in the wear-resistant castable; the nozzles of the air flow nozzles are all located on the receiving surface of the blowing grate module, and the receiving surface of the blowing grate module is the upper surface of the blowing grate module; along the material flow direction, the angle γ1 formed by the spraying direction of the nozzle of the air flow nozzle located on the rear side and the receiving surface of the blowing grate module is 10 to 35 degrees, and the angles formed by the spraying directions of the nozzles of the remaining air flow nozzles and the receiving surface of the blowing grate module are equal to the angle γ1, or gradually decrease; the air flow entering the air flow nozzle is sprayed upward along the receiving surface of the blowing grate module, driving the material to spray upward to form a parabolic path and move forward, thereby increasing the sufficient contact time with the high-temperature air.

2. The prefabricated composite blowing grate module according to claim 1, characterized in that: The shell and the air flow nozzle are made of heat-resistant steel with a temperature resistance of 1000-1300°C.

3. The prefabricated composite blowing grate module according to claim 1, characterized in that: The material receiving surface of the blowing grate module is covered with a high-temperature resistant SiC plate.

4. The prefabricated composite blowing grate module according to claim 1, characterized in that: The cross section of the airflow nozzle gradually changes into a flat and narrow form from the inlet to the nozzle in the transverse direction, and the instantaneous speed of the airflow released after the airflow nozzle sprays the air is supersonic.

5. The prefabricated composite blowing grate module according to claim 1, characterized in that: Each air flow nozzle in each of the blowing grate modules uses the same inlet to supply air, and the air flow supplied by the blowing grate module is high-pressure combustion-supporting air or fuel gas.

6. A blowing conveying bottom plate, characterized in that: The blowing conveying bottom plate is composed of a blowing grate module that is arranged in multiple levels in the longitudinal direction and multiple columns in the transverse direction and is placed obliquely, and a discharge grate module located at the end of the blowing conveying bottom plate. The blowing grate module is the prefabricated composite blowing grate module described in any one of claims 1 to 5; the blowing conveying bottom plate is arranged obliquely downward along the material flow direction, and the blowing conveying bottom plate is divided into three zones along the material flow direction: preheating section, combustion section, and discharge section in sequence. The preheating section, combustion section, and discharge section are respectively provided with different grate module combinations to form a blowing conveying bottom plate with a gradient distribution, so as to realize the upward tumbling of the bottom material and the forward transportation of the alternative fuel on the blowing conveying bottom plate.

7. The blowing conveying bottom plate according to claim 6, characterized in that: The blowing grate modules are arranged tilted downward along the material flow direction, with an inclination angle α of 2 to 10°; between two adjacent levels of blowing grate modules, the nozzle of the air flow nozzle located at the rear side along the material flow direction is located at the overlapping intersection of the upper and lower layers of blowing grate modules.

8. The blowing conveying bottom plate according to claim 6, characterized in that: The receiving surface length of a single blowing grate module in the preheating section is greater than the receiving surface length of a single blowing grate module in the combustion section. The preheating section is provided with 1 to 3 levels of blowing grate modules, and the preheating section angle β1 is 15 to 28°; the combustion section is provided with 2 to 6 levels of blowing grate modules, and the combustion section angle β2 is 28 to 35°; the discharging section is provided with 1 to 2 levels of discharging grate modules, and the discharging section angle β3 is 45 to 60°; and β1 < β2 < β3.

9. A grate-type pre-combustion furnace for processing alternative fuels, comprising a combustion chamber and the blowing and conveying base plate according to any one of claims 6 to 8, wherein the blowing and conveying base plate is located at the bottom of the combustion chamber, and the discharge grate module of the blowing and conveying base plate extends into the combustion furnace. The combustion chamber is provided with an alternative fuel inlet, a high-temperature air inlet and a sand inlet. An alternative fuel inlet and a high-temperature air inlet are provided at one end of the combustion chamber, and the high-temperature air inlet is connected to a high-temperature air inlet pipe. The other end of the combustion chamber is connected to the combustion furnace, and the sand inlet is located at the dome of the combustion chamber and / or the high-temperature air inlet.

10. The grate type pre-combustion furnace for processing alternative fuels according to claim 9, characterized in that: The sand material is a calcium-based mineral material.

11. The grate type pre-combustion furnace for processing alternative fuels according to claim 9, characterized in that: The top of the combustion chamber is provided with a plurality of temperature measuring points for monitoring temperature distribution and a high-temperature camera for monitoring combustion status, and the outlet of the combustion chamber is provided with a gas composition measuring point for monitoring outlet gas composition.

12. The grate type pre-combustion furnace for processing alternative fuels according to claim 9, characterized in that: The alternative fuel inlet is located at the high-temperature air inlet and / or below the high-temperature air inlet; when located at the high-temperature air inlet, a scattering box is provided at the alternative fuel inlet, and the alternative fuel is scattered into the high-temperature air inlet pipe by the scattering box and fed into the combustion chamber together with the high-temperature air; when located below the high-temperature air inlet, an alternative fuel feeding device is provided at the alternative fuel inlet, and the alternative fuel is fed into the combustion chamber by the alternative fuel feeding device.

13. The grate type pre-combustion furnace for processing alternative fuels according to claim 9, characterized in that: The blowing working mode of the blowing conveying bottom plate is set according to the principle of traversing the entire row of small cycles, the two adjacent blowing grate modules of different levels are separated by at least one step, and the order of each level of blowing is based on the dome temperature monitoring data, from the low temperature zone to the high temperature zone. The blowing grate modules of the same level adopt non-adjacent blowing to prevent the material from entering the grate gap formed by the nozzles of the blowing grate modules of the adjacent rows, and finally traverse all the blowing grate modules. The operating frequency of the injection grate module is calculated based on the average temperature of multiple temperature measurement points on the top of the combustion chamber. The formula is as follows: Among them, T avg is the average temperature of multiple points, in degrees; τintel is the interval between two adjacent injections, in seconds.

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