Manufacturing method for preparing white carbon black by burning rice husks and horizontal circulating fluidized bed boiler

Abstract

The invention relates to the technical field of preparation of white carbon black by combustion of rice husks, in particular to a method for preparing white carbon black by combustion of rice husks and a horizontal circulating fluidized bed boiler. The amount of air is in the range of 75-95% of the theoretical combustion air amount required by combustion of the rice husks, and the temperature in the combustion chamber is controlled in the temperature range of 650-750 DEG C; in the first separation stage, a first product rich in white carbon black generated by low-temperature combustion of rice husks in the combustion chamber is collected through a first separator arranged at the downstream of the combustion chamber, and the remaining first flue gas flows to the burnout chamber; according to the manufacturing method for preparing the white carbon black by combustion of the rice hulls, the oxygen supply amount in the combustion chamber of the horizontal circulating fluidized bed boiler is limited to inhibit complete combustion of the rice hulls, the combustion temperature is controlled to be lower than 750 DEG C, amorphous silicon dioxide is reserved in rice hull ash, and then qualified white carbon black is manufactured on a large scale at low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of producing silica white by burning rice husks, and particularly relates to a manufacturing method for producing silica white by burning rice husks and a horizontal circulating fluidized bed boiler. Background Art

[0002] Using rice husks as fuel, burning the rice husks, utilizing the heat energy generated during the burning process and obtaining silica white products is the best way to utilize rice husks.

[0003] In the prior art, silica white is usually manufactured by putting rice husks into a grate rotary kiln for incomplete combustion. The manufacturing efficiency is low and the quality of the obtained silica white is unstable after manufacturing. Large-scale production of silica white cannot be achieved. The incomplete combustion of rice husks not only causes energy waste, but also leads to poor emission performance and poor economy. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems in the above technologies to some extent. For this purpose, the present invention proposes a manufacturing method for producing silica white by burning rice husks, which can achieve large-scale and low-cost production of qualified silica white, and at the same time, the heat energy generated during the burning process can also be fully utilized.

[0005] The present invention also proposes a horizontal circulating fluidized bed boiler that can use rice husks to produce silica white.

[0006] To achieve the above object, a first aspect embodiment of the present invention proposes a manufacturing method for producing silica white by burning rice husks, which is applied to a horizontal circulating fluidized bed boiler. The method includes:

[0007] In the fluidized combustion stage, air and rice husk fuel are supplied into the combustion chamber. The amount of the air is in the range of 75% to 95% of the theoretical combustion air amount required for the combustion of the rice husks, and the temperature in the combustion chamber is controlled within the temperature range of 650°C - 750°C.

[0008] In the first separation stage, a first product rich in the silica white generated by the low-temperature combustion of the rice husks in the combustion chamber is collected through a first separator provided downstream of the combustion chamber, and the remaining first flue gas flows towards the burnout chamber.

[0009] According to the manufacturing method for producing silica white by burning rice husks of the embodiment of the present invention, by restricting the oxygen supply amount in the combustion chamber of the horizontal circulating fluidized bed boiler to inhibit the complete combustion of the rice husks and controlling the combustion temperature below 750°C, amorphous silica is retained in the rice husk ash, thereby realizing large-scale and low-cost production of qualified silica white.

[0010] According to an embodiment of the present invention, supplying air into the combustion chamber includes:

[0011] Supply primary air and secondary air to the combustion chamber in sequence;

[0012] Among them, before supplying primary air to the combustion chamber, a first gas is incorporated into the primary air, and the proportion of the first gas after mixing with the primary air is within the range of 30% to 40%. The first gas is the flue gas discharged after sufficient combustion and treatment inside the horizontal circulating fluidized bed boiler.

[0013] According to an embodiment of the present invention, during the process of supplying the secondary air to the combustion chamber, part of the secondary air forms a disturbance airflow. The flow direction of the disturbance airflow inclines downward in the direction away from the wall surface, and the airflow velocity is within a first velocity range.

[0014] According to an embodiment of the present invention, in the first separation stage, the first product is collected in a cold ash hopper provided below the first separator and sealed. The method further includes: in the cooling stage, the cold ash hopper cools the first product.

[0015] According to an embodiment of the present invention, the method further includes: in the burnout stage, supply a third air to the burnout chamber, and the amount of the third air is within the range of 110% to 130% of the theoretical combustion air amount required for the rice husk combustion.

[0016] According to an embodiment of the present invention, the method further includes:

[0017] In the second separation stage, collect a second product generated by the combustion of the first flue gas in the burnout chamber through a second separator provided downstream of the burnout chamber. The second product is collected in a loop seal provided below the second separator to form a loop seal material, and the remaining second flue gas flows toward the outlet flue;

[0018] In the loop seal material stage, the loop seal returns the loop seal material to the combustion chamber.

[0019] According to an embodiment of the present invention, the...

[0020] An embodiment of the second aspect of the present invention provides a horizontal circulating fluidized bed boiler, characterized in that it manufactures silica white by the above manufacturing method of producing silica white by burning rice husk;

[0021] The horizontal circulating fluidized bed boiler includes:

[0022] A combustion chamber, including a main combustion chamber and an auxiliary combustion chamber. The upper end of the auxiliary combustion chamber is communicated with the upper end of the main combustion chamber;

[0023] An afterburning chamber, the lower end of the afterburning chamber is communicated with the lower end of the secondary combustion chamber;

[0024] A first separator, arranged below the secondary combustion chamber and the afterburning chamber;

[0025] A cold ash cooler, arranged on the first separator, the inlet of the cold ash cooler is communicated with the first separator;

[0026] A second separator, communicated with the upper end of the afterburning chamber;

[0027] A material returner, arranged below the second separator, the input end of the material returner is communicated with the second separator, and the output end of the material returner is communicated with the combustion chamber;

[0028] An outlet flue, communicated with the second separator;

[0029] A tail shaft, the tail shaft is connected with the outlet flue, and the flue gas flowing through the second separator enters the tail shaft through the outlet flue.

[0030] According to an embodiment of the present invention, the horizontal circulating fluidized bed boiler further includes:

[0031] A flue gas treatment mechanism, arranged downstream of the tail shaft, including a deacidification tower, a bag filter and a fan;

[0032] A chimney, used for discharging the discharged flue gas after being treated by the flue gas treatment mechanism to the outside;

[0033] A recirculation flue, the inlet is communicated with the downstream of the flue gas treatment mechanism, and the outlet is communicated with the outlet of a primary air fan that conveys primary air to the combustion chamber.

[0034] According to an embodiment of the present invention, the first separator includes a first flue gas guiding part and a second flue gas guiding part, the flue gas in the first flue gas guiding part flows from top to bottom, the flue gas in the second flue gas guiding part flows from bottom to top, a first smoke baffle is arranged inside the first flue gas guiding part, the first smoke baffle extends obliquely downward from the flue wall to the inside of the flue, a second smoke baffle is arranged in the second flue gas guiding part, and the second smoke baffle extends obliquely downward from the flue wall to the inside of the flue.

[0035] Wherein, the number of the second smoke baffles is greater than the number of the first smoke baffles.

[0036] According to an embodiment of the present invention, the main combustion chamber includes a gasification zone and a combustion zone, and a refractory material layer is laid on the water-cooled wall of the gasification zone.

[0037] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0039] Figure 1 is a flowchart of a manufacturing method for producing silica white by burning rice husks according to an embodiment of the present invention;

[0040] Figure 2 is a partial flowchart of the manufacturing method for producing silica white by burning rice husks in the fluidized combustion stage according to an embodiment of the present invention;

[0041] Figure 3 is a schematic structural diagram of a horizontal circulating fluidized bed boiler according to an embodiment of the present invention.

[0042] Reference numerals:

[0043] Horizontal circulating fluidized bed boiler 100, combustion chamber 1, main combustion chamber 11, gasification zone 111, refractory material layer 1111, combustion zone 112, secondary combustion chamber 12,

[0044] First separator 2, cold ash cooler 21, first flue gas guiding part 22, second flue gas guiding part 23,

[0045] Burnout chamber 3, second separator 4, return feeder 41, outlet flue 5, tail shaft 6, flue gas treatment mechanism 7, deacidification tower 71, bag filter 72, chimney 8, recirculation flue 9, primary air blower 101. Detailed implementation manners

[0046] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0047] The manufacturing method for producing silica white by burning rice husks and the horizontal circulating fluidized bed boiler according to the embodiments of the present invention will be described below in conjunction with the drawings.

[0048] Using rice husks as fuel, by burning the rice husks, utilizing the heat energy generated during the combustion process and obtaining silica white products is the best way to utilize rice husks.

[0049] In the prior art, the production of silica white is usually achieved by putting rice husks into a grate rotary kiln for incomplete combustion. The production efficiency is low, and the quality of the silica white obtained after production is unstable. Large-scale production of silica white cannot be achieved. The incomplete combustion of rice husks not only causes energy waste but also leads to poor emission performance and poor economy.

[0050] To this end, an embodiment of the present invention provides a manufacturing method for producing silica white by burning rice husks. This manufacturing method is applied to a horizontal circulating fluidized bed boiler 100. Due to the high efficiency, environmental protection, and economy of the horizontal circulating fluidized bed boiler 100, large-scale production of silica white can be achieved.

[0051] That is to say, the rice husk combustion process is completed inside the horizontal circulating fluidized bed boiler 100. Since the horizontal circulating fluidized bed boiler 100 is a high-efficiency and low-pollution industrial boiler, it can utilize fluidized bed combustion technology and has a wide fuel adaptability. That is, the horizontal circulating fluidized bed boiler 100 can adapt to burning rice husks. Thanks to its low-temperature combustion and staged combustion technologies, the horizontal circulating fluidized bed boiler 100 can effectively inhibit the conversion of nitrogen in the fuel into NOX and promote the reduction of some already generated NOX, achieving low nitrogen oxide emissions and having high combustion efficiency and load regulation ability.

[0052] Due to the above advantages of the horizontal circulating fluidized bed boiler 100, therefore, the manufacturing method for producing silica white by burning rice husks using the horizontal circulating fluidized bed boiler 100 proposed in the embodiment of the present invention also has the above advantages.

[0053] According to an embodiment of the present invention, the combustion of rice husks in the horizontal circulating fluidized bed boiler 100 includes multiple different combustion stages, including a fluidized combustion stage occurring in the combustion chamber 1 and a burnout stage occurring in the burnout chamber 3. Before the burnout stage, there is also a first separation stage that can achieve the separation of solid substances and gaseous substances inside the flue gas.

[0054] The manufacturing method for producing silica white by burning rice husks according to an embodiment of the present invention includes the following steps:

[0055] S1: In the fluidized combustion stage, supply air and rice husk fuel into the combustion chamber 1.

[0056] In the process of producing silica white by burning rice husks, it is crucial to avoid too high a combustion temperature and ensure the retention of amorphous silica in the rice husk ash. Avoiding high-temperature combustion above 800 °C can cause the crystallization of the product and the formation of crystal products such as cristobalite. The control of the combustion temperature is related to the amount of air supplied to the fuel during the combustion process.

[0057] In the manufacturing method of the present invention, the combustion temperature can be controlled by restricting the air supply amount, that is, the oxygen supply amount, inside the combustion chamber 1 to inhibit the complete combustion of rice husks in the combustion chamber 1, ensuring that the combustion temperature is always lower than 750 °C, and ensuring that enough amorphous silica, which is the main component of silica white, is retained in the product generated after the fluidized combustion stage.

[0058] Among them, in the fluidized combustion stage, the amount of air supplied into the combustion chamber 1 is in the range of 75% to 95% of the theoretical combustion air amount required for the combustion of rice husks, and the temperature inside the combustion chamber 1 is controlled within the temperature range of 650°C - 750°C.

[0059] As the first step in the whole process of burning rice husks by the horizontal circulating fluidized bed boiler 100, the fluidized combustion stage requires regularly and quantitatively feeding the fuel, that is, rice husks, into the combustion chamber 1, calculating the oxygen content required for the combustion of a certain amount of rice husks, and then obtaining the theoretical combustion air amount. When supplying air into the combustion chamber 1, the air amount is controlled according to the calculated theoretical combustion air amount. In order to achieve the control of the combustion temperature, the supplied air amount should not be higher than the theoretical combustion air amount.

[0060] Preferably, the amount of air supplied into the combustion chamber 1 is in the range of 75% to 95% of the theoretical combustion air amount required for the combustion of rice husks, so as to control the temperature inside the combustion chamber 1 within the temperature range of 650°C - 750°C, ensuring the retention of the amorphous silica form and ensuring the combustion efficiency of the horizontal circulating fluidized bed boiler 100.

[0061] S2: In the first separation stage, the first separator 2 provided downstream of the combustion chamber 1 collects the first product rich in silica white produced by the low-temperature combustion of rice husks in the combustion chamber 1, and the remaining first flue gas flows towards the burnout chamber 3.

[0062] In the fluidized combustion stage, under the action of low-temperature combustion, the flue gas generated by rice husks will flow downstream along the flue. The flue gas includes combustible gases produced by incomplete combustion and solid particles rich in amorphous silica.

[0063] The flue gas generated in the fluidized combustion stage enters the first separation stage during the process of flowing through the first separator 2. In the first separator 2, some of the coarse ash with a large particle size and high silicon content in the flue gas is separated from the flue gas under the separation action of the first separator 2 and is collected by the first separator 2, producing the first product rich in silica white.

[0064] After the separation of the flue gas, it forms the first flue gas. The first flue gas contains combustible gases and the remaining fine ash with smaller particle sizes. The first flue gas flows towards the burnout chamber 3 and undergoes further high-temperature full combustion in the burnout chamber 3.

[0065] That is to say, the first separator 2 separates and collects the amorphous silica inside the flue gas before the flue gas enters high-temperature combustion, so that it does not participate in the subsequent high-temperature combustion process. On the one hand, the collection and manufacture of white carbon black are realized, and the change of the morphology of amorphous silica under the action of high-temperature combustion is avoided. On the other hand, the high-temperature complete combustion in the subsequent burnout chamber 3 can fully utilize the combustible gas inside the first flue gas, improving the comprehensive thermal efficiency.

[0066] In summary, the manufacturing method according to the embodiment of the present invention realizes the large-scale manufacture of white carbon black by applying the horizontal circulating fluidized bed boiler 100, ensures the quality of white carbon black, ensures low nitrogen oxide emissions during the manufacture of white carbon black, improves the combustion efficiency of rice husks, enables the full combustion of rice husks, and improves the comprehensive thermal efficiency.

[0067] According to the manufacturing method for producing white carbon black by burning rice husks according to the embodiment of the present invention, by restricting the oxygen supply amount in the combustion chamber 1 of the horizontal circulating fluidized bed boiler 100 to inhibit the complete combustion of rice husks and controlling the combustion temperature below 750 °C, amorphous silica is retained in the rice husk ash, thereby realizing the large-scale and low-cost manufacture of qualified white carbon black.

[0068] Referring Figure 2 , supplying air into the combustion chamber 1 includes sequentially supplying primary air and secondary air into the combustion chamber 1. When supplying primary air into the combustion chamber 1, primary air generates primary wind during the flowing process, and when supplying secondary air into the combustion chamber 1, secondary air generates secondary wind during the flowing process.

[0069] In the horizontal circulating fluidized bed boiler 100, sequentially supplying primary wind and secondary wind into the combustion chamber 1 is a key parameter for controlling the combustion process, directly affecting the combustion efficiency and the emission of pollutants.

[0070] Among them, the primary wind is formed by the primary air fed from the bottom of the combustion chamber 1. Its main function is to fluidize the fuel and bed material (such as sand), making it in a "boiling" state to form a fluidized bed. Among them, the primary wind provides sufficient wind pressure and wind speed to mix and suspend the fuel and bed material, enabling the fuel to be fluidized. The fuel is ignited in the low-temperature zone at the bottom of the fluidized bed to maintain the basic combustion reaction. The wind speed is high and the temperature is low, avoiding coking at the bottom.

[0071] The secondary wind is formed by the secondary air fed in layers from the upper middle part or the side of the combustion chamber 1. Its main function is to supplement oxygen, promote fuel combustion, and control the combustion temperature. By "staged combustion", the flame temperature is reduced, and the generation of nitrogen oxides is reduced. The wind speed of the secondary wind is low, but the coverage range is wide, and it is often preheated to improve the combustion efficiency. The secondary wind can make the fire in the combustion chamber 1 burn more evenly and thoroughly. The cooperation of the primary wind and the secondary wind can realize the efficient and clean operation of the horizontal circulating fluidized bed boiler 100.

[0072] Specifically, the method of supplying air into the combustion chamber 1 includes:

[0073] S101: Mix a first gas into the primary air;

[0074] Since the primary air flow in the combustion chamber 1 is required to fluidize the fuel and bed material during the primary air flow process, so that it is in a "boiling" state to form a fluidized bed. In this application, in order to ensure that the temperature in the combustion chamber 1 is lower than 750 degrees Celsius, the air supply amount in the combustion chamber 1 is reduced, that is, the amount of primary air is reduced. As a result, the wind force of the primary air generated by the primary air flow is small, and the fuel and bed material cannot be fluidized.

[0075] Therefore, by mixing a first gas with low oxygen content into the primary air before the primary air enters the combustion chamber 1, so that the mixed gas formed after the two are mixed enters the combustion chamber 1 together to form the primary air, it can ensure the wind force of the primary air, ensure that the primary air can fluidize the fuel and bed material, and at the same time, the oxygen content in the primary air will not affect the oxygen content in the combustion chamber 1, and thus will not affect the combustion temperature in the combustion chamber 1, ensuring the quality of the silica white produced.

[0076] Among them, the proportion of the first gas after mixing with the primary air is in the range of 30% to 40% to ensure that the first gas can make up for the gas gap generated after the reduction of the primary air supply amount.

[0077] In some embodiments, the first gas is the flue gas discharged after being fully burned and processed inside the horizontal circulating fluidized bed boiler 100. The flue gas has a low oxygen content after being fully burned, and there is no need to design equipment or structures in the horizontal circulating fluidized bed boiler 100 that can generate the first gas with low oxygen content, reducing the production cost.

[0078] Moreover, the gas in the flue gas that is easy to corrode the pipeline is fully processed to form the flue gas discharged. The flue gas will not corrode the pipeline during the process of being transported back, nor will it cause harm due to leakage or other reasons, improving the safety and the service life of the equipment.

[0079] S102: Supply the primary air into the combustion chamber 1;

[0080] Since the primary air is mixed with the first gas with low oxygen content before being transported into the combustion chamber 1, thus, supplying the primary air into the combustion chamber 1 means transporting the mixed gas of the flue gas discharged and the primary air into the combustion chamber 1. This mixed gas provides sufficient air volume and a certain amount of oxygen in the combustion chamber 1, and the formed primary air fluidizes the fuel and bed material, and a certain amount of oxygen ensures the combustion of the fuel.

[0081] In some embodiments, the amount of primary air supplied into the combustion chamber 1 is 2 / 3 of the total air amount to reduce the combustion temperature while ensuring combustion.

[0082] S103: Supply secondary air into the combustion chamber 1;

[0083] The amount of primary air supplied into the combustion chamber 1 is 1 / 3 of the total air amount to supplement oxygen, promote fuel combustion, and control the combustion temperature. The flame temperature is reduced through "staged combustion" to reduce the generation of nitrogen oxides.

[0084] Among them, during the process of supplying secondary air into the combustion chamber 1, part of the secondary air forms a disturbance air flow. The flow direction of the disturbance air flow is inclined downward in the direction away from the wall surface, and the air flow velocity is within the first velocity range, that is, the velocity range greater than 50 m / s and less than 70 m / s.

[0085] Part of the secondary air is injected at a downward inclination angle at a high speed, which can form a strong swirling flow field in the combustion chamber 1, improve the uniformity of material mixing in the combustion chamber 1, and further improve the combustion uniformity in the combustion chamber 1.

[0086] In some embodiments, secondary air upper inlet holes and secondary air lower inlets are formed on the wall surface of the combustion chamber 1. The secondary air is supplied into the combustion chamber 1 through the secondary air upper inlet holes and the secondary air lower inlets. Among them, the intake air flow at the secondary air lower inlet is injected at a high speed of 60 m / s at a downward inclination angle of 45° to form a disturbance air flow for improving the uniformity of material mixing in the combustion chamber 1 and the combustion uniformity in the combustion chamber 1.

[0087] Further, as Figure 1 and Figure 3 shown, in the first separation stage, the first separator 2 will separate part of the coarse particle solids from the flue gas to generate a solid product and a gas product. The solid product is the first product, and the gas product is the first flue gas. The two different products will be processed differently subsequently.

[0088] Under the action of gravity, the first product gathers downward. A cold ash hopper 21 is provided below the first separator 2. Therefore, the first product will finally gather in the cold ash hopper 21 provided below the first separator 2 and sealed. The first flue gas flows upward and flows into the burnout chamber 3 for burnout treatment.

[0089] Further, referring to Figure 1 , the manufacturing method further includes:

[0090] S31: In the cooling stage, the cold ash hopper 21 cools the first product.

[0091] Among them, the cold ash machine itself needs to be sealed, and the first product inside is cooled by water cooling. The interface between the cold ash machine and the first separator 2 also needs to be sealed. The cold ash machine is directly integrated below the first separator 2, and its sealing performance is ensured, which can prevent the first product from being exposed to air, resulting in secondary oxidation or moisture absorption and caking. Rapidly cooling the first product by water cooling can fix the amorphous silica structure and prevent its phase change under high temperature.

[0092] The first flue gas flows towards the burnout chamber 3 and enters the burnout stage. In the burnout stage, since the flue gas has been fully fluidized, combustible gases or solids can fully contact with oxygen, and the combustible substances inside the flue gas can be fully burned in an oxygen-rich state, improving the emission performance of the horizontal circulating fluidized bed boiler 100 while avoiding energy waste.

[0093] The manufacturing method further includes: S32: In the burnout stage, supply the third air into the burnout chamber 3, and the amount of the third air is in the range of 110% to 130% of the theoretical combustion air amount required for rice husk combustion.

[0094] Thus, the combustion state of the flue gas changes from a state of restricting the oxygen supply amount and suppressing complete combustion to combustion under excess air. The combustible substances inside the flue gas can be fully burned in an oxygen-rich state, improving the emission performance of the horizontal circulating fluidized bed boiler 100 while avoiding energy waste, ensuring the carbon burnout rate in the flue gas, and preventing carbon residue from polluting the white carbon black.

[0095] Refer to Figure 1 and Figure 3 , the manufacturing method further includes:

[0096] S42: In the second separation stage, collect the returned materials generated by the combustion of the first flue gas in the burnout chamber 3 through the second separator 4 provided downstream of the burnout chamber 3. The second product is collected in the return feeder 41 provided below the second separator 4, and the remaining second flue gas flows towards the outlet flue 5;

[0097] Among them, the first separator 2 can separate some large-particle-size ash particles in the flue gas upstream of the burnout chamber 3, while the second separator 4 can separate some small-particle-size ash particles in the flue gas after full combustion downstream of the burnout chamber 3. Among them, the first separator 2 mainly collects the high-silica-content coarse ash with a particle size greater than 50μm in the flue gas in the cold ash cooler 21, and the second separator 4 mainly collects the fine ash with a particle size greater than 20μm in the flue gas in the return chamber.

[0098] S51: In the return stage, the return feeder 41 transports the returned materials back to the combustion chamber 1.

[0099] Thus, the horizontal circulating fluidized bed boiler 100 can recycle fine ash back to the combustion chamber 1 for re-combustion, further improving the carbon utilization rate of the horizontal circulating fluidized bed boiler 100 during the production process.

[0100] In a second aspect embodiment of the present invention, a horizontal circulating fluidized bed boiler 100 is provided, characterized in that it manufactures silica white by the above-mentioned manufacturing method of producing silica white by burning rice husks.

[0101] As Figure 3 shown, the horizontal circulating fluidized bed boiler 100 includes a combustion chamber 1, a burnout chamber 3, an outlet flue 5, and a tail shaft 6 that are sequentially connected to form a complete flue. Fuel burns and releases heat therein, and the water-cooled walls provided on the flue wall surface and the economizer and superheater provided in the tail shaft 6 jointly absorb the heat generated during the combustion process and the waste heat in the flue gas, realizing the utilization of heat by the horizontal circulating fluidized bed boiler 100.

[0102] The first separator 2 can separate some large-particle-size ash particles in the flue gas upstream of the burnout chamber 3, and the second separator 4 can separate some small-particle-size ash particles in the flue gas after sufficient combustion downstream of the burnout chamber 3. Among them, the first separator 2 can mainly collect the coarse ash with a high silicon content having a particle size greater than 50 μm in the flue gas into the cold ash hopper 21 to obtain a first product rich in silica white. The second separator 4 mainly collects the fine ash with a particle size greater than 20 μm in the flue gas, that is, the second product, into the return chamber, and the return chamber conveys the fine ash back to the combustion chamber 1 for re-combustion, further improving the carbon utilization rate of the horizontal circulating fluidized bed boiler 100 during the production process.

[0103] Among them, the combustion chamber 1 includes a main combustion chamber 11 and an auxiliary combustion chamber 12. The upper end of the auxiliary combustion chamber 12 is connected to the upper end of the main combustion chamber 11. Since the main combustion chamber 11 is formed into a vertically extending flue structure, the solid combustibles flow up and down under the action of the air flow to realize the fluidized combustion of the fuel. The auxiliary combustion chamber 12 is located on one side of the main combustion chamber 11, and the solid fuel is not easily introduced into the auxiliary combustion chamber 12 under the action of gravity. Instead, more of the flue gas generated by the combustion in the main combustion chamber 11 enters the auxiliary combustion chamber 12, and the fuel residue is more likely to return to the main combustion chamber 11 under the action of gravity for continuous fluidized combustion.

[0104] The burnout chamber 3, the lower end of the burnout chamber 3 is connected to the lower end of the auxiliary combustion chamber 12, and the first separator 2 is provided below the auxiliary combustion chamber 12 and the burnout chamber 3.

[0105] Thus, as the flue gas flows downstream along the flue, it first passes through the secondary combustion chamber 12 and flows downward in the secondary combustion chamber 12. When it reaches the first separator 2, under the combined action of the flue gas and gravity, the particulate matter in the flue gas is more likely to enter the first separator 2. The treated first flue gas flows towards the burnout chamber 3. During the process of flowing towards the burnout chamber 3, the first flue gas flows upward. Due to the action of gravity, the heavier part of the particulate matter in the flue gas can overcome the airflow drive and return to the first separator 2, ensuring the separation effect of the first separator 2.

[0106] Furthermore, the cold ash cooler 21 is arranged on the first separator 2. The inlet of the cold ash cooler 21 is communicated with the first separator 2. After the first separator 2 separates the first product from the flue gas, the first product will gather downward under the action of gravity and enter the cold ash cooler 21 through the inlet of the cold ash cooler 21. The cold ash cooler 21 can perform water-cooling treatment on the first product, cooling the first product at 700 °C to room temperature. Since the cooling speed is fast during the water-cooling process, it can quickly cool the first product to fix the amorphous silica structure and prevent its phase change at high temperature, providing the product whiteness of the precipitated silica obtained in production.

[0107] The second separator 4 is communicated with the upper end of the burnout chamber 3. The return feeder 41 is arranged below the second separator 4. The input end of the return feeder 41 is communicated with the second separator 4, and the output end of the return feeder 41 is communicated with the combustion chamber 1. The return feeder 41 conveys the returned material back to the combustion chamber 1. Thus, the horizontal circulating fluidized bed boiler 100 can recycle the fine ash back into the combustion chamber 1 for re-combustion, further improving the carbon utilization rate of the horizontal circulating fluidized bed boiler 100 during the production process.

[0108] The outlet flue 5 is communicated with the second separator 4 and is used to convey the second flue gas after separation treatment to the tail shaft 6. The tail shaft 6 is connected to the outlet flue 5. The flue gas flowing through the second separator 4 enters the tail shaft 6 through the outlet flue 5. In the tail shaft 6, there are a superheater and a economizer, which can absorb the remaining heat in the flue gas inside the tail shaft 6 and make better use of the heat energy in the flue gas.

[0109] According to an embodiment of the present invention, referring to Figure 3 , the horizontal circulating fluidized bed boiler 100 further includes a flue gas treatment mechanism 7 arranged downstream of the tail shaft 6, including a deacidification tower 71, a bag filter 72 and a fan, which are used to treat the harmful substances in the flue gas discharged to the outside to ensure that the emissions generated during the production process meet the national standards.

[0110] Finally, the treated discharged flue gas flows towards the chimney 8, and the chimney 8 discharges the discharged flue gas treated by the flue gas treatment mechanism 7 to the outside.

[0111] Referring to Figure 3, the horizontal circulating fluidized bed boiler 100 further includes a recirculation flue 9. The inlet of the recirculation flue 9 is communicated with the downstream of the flue gas treatment mechanism 7, and the outlet is communicated with the outlet of the primary air blower 101 that conveys primary air to the combustion chamber 1.

[0112] Through the recirculation flue 9, it is possible to facilitate the introduction of the first gas into the primary air before the horizontal circulating fluidized bed boiler 100 supplies primary air to the combustion chamber 1.

[0113] Since the primary air generated during the flow of the primary air in the combustion chamber 1 is required to fluidize the fuel and the bed material, making it in a "boiling" state to form a fluidized bed. In this application, in order to ensure that the temperature in the combustion chamber 1 is lower than 750 degrees Celsius, the air supply in the combustion chamber 1 is reduced, that is, the amount of primary air is reduced. As a result, the primary air flow generated by the primary air is relatively small, and it is impossible to fluidize the fuel and the bed material.

[0114] Therefore, by introducing the flue gas with low oxygen content into the primary air before the primary air enters the combustion chamber 1, so that the mixed gas formed after the two are mixed enters the combustion chamber 1 together to form the primary air, it can ensure the wind force of the primary air, ensure that the primary air can fluidize the fuel and the bed material, and at the same time, the oxygen content in the primary air will not affect the oxygen content in the combustion chamber 1, and thus will not affect the combustion temperature in the combustion chamber 1, ensuring the quality of the precipitated silica produced.

[0115] The flue gas generated after sufficient combustion and treatment inside the horizontal circulating fluidized bed boiler 100 has a low oxygen content after sufficient combustion. There is no need to design equipment or structures that can generate the first gas with low oxygen content in the horizontal circulating fluidized bed boiler 100, reducing the production cost.

[0116] Moreover, the flue gas has been fully treated and is not corrosive. It is not easy to be corroded inside the recirculation flue 9, improving the safety and the service life of the equipment.

[0117] As Figure 3 shown, the first separator 2 includes a first smoke guiding part 22 and a second smoke guiding part 23. The flue gas in the first smoke guiding part 22 flows from top to bottom, and the flue gas in the second smoke guiding part 23 flows from bottom to top. A first smoke baffle is provided inside the first smoke guiding part 22, and the first smoke baffle extends obliquely downward from the flue wall towards the inside of the flue.

[0118] A second smoke baffle is provided inside the second smoke guiding part 23. The second smoke baffle extends obliquely downward from the flue wall towards the inside of the flue, and is used to block the solid particulate matter in the flue gas to prevent it from continuing to flow upward into the burnout chamber 3 under the drive of the flue gas, ensuring that the amorphous silica in the flue gas can be fully separated and collected, and ensuring the production efficiency of the precipitated silica.

[0119] The first smoke baffle and the second smoke baffle are arranged to form a structure of a trough-shaped separator in the first separator 2 to improve the efficiency of separating solid particles from the flue gas. Among them, the number of the second smoke baffles is greater than that of the first smoke baffles, that is, more second smoke baffles are arranged to further improve the production efficiency of silica white.

[0120] According to an embodiment of the present invention, referring to Figure 3 , the main combustion chamber 11 includes a gasification zone 111 and a combustion zone 112. A refractory layer 1111 is laid on the water-cooled wall of the gasification zone 111. The refractory layer 1111 can isolate the heat transfer between the water-cooled wall and the gasification zone 111, avoiding the water-cooled wall absorbing a large amount of heat in the gasification zone 111, resulting in an excessive temperature fluctuation range in the gasification zone 111 and affecting the ash stability.

[0121] The inner wall surfaces of the first separator 2 and the second separator 4 are also laid with refractory layer 1111 to isolate the heat transfer to the water-cooled wall, avoiding the water-cooled wall absorbing a large amount of heat in the first separator 2 or the second separator 4, resulting in an excessive temperature drop during the process of the flue gas flowing through the separator and affecting the product stability.

[0122] The inner wall surface of the tail shaft 6 is also laid with refractory layer 1111 to avoid the water-cooled wall absorbing a large amount of heat of the flue gas in the tail shaft 6, resulting in the superheater and economizer in the tail shaft 6 being unable to better absorb the heat in the flue gas and causing heat loss.

[0123] Since the manufacturing method for producing silica white by burning rice husks according to the embodiment of the present invention has the above beneficial technical effects, and the horizontal circulating fluidized bed boiler 100 according to the embodiment of the present invention can use the manufacturing method according to the embodiment of the present invention to produce silica white by burning rice husks, therefore, the horizontal circulating fluidized bed boiler 100 of the present invention can manufacture high-quality silica white on a large scale and efficiently, reducing the production and processing cost of silica white.

[0124] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0125] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0126] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0127] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0128] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0129] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as a limitation to the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for producing white carbon black by burning rice husks, characterized in that: Applied to a horizontal circulating fluidized bed boiler, the method comprises: In the fluidized combustion stage, air and rice husk fuel are supplied into the combustion chamber, wherein the amount of air is in the range of 75% to 95% of the theoretical combustion air amount required for the combustion of the rice husk, and the temperature in the combustion chamber is controlled in the range of 650° C. to 750° C.; In the first separation stage, the first product rich in white carbon black generated by the low-temperature combustion of the rice husk in the combustion chamber is collected by a first separator arranged downstream of the combustion chamber, and the remaining first flue gas flows to the burnout chamber.

2. The method for producing white carbon black by burning rice husk according to claim 1, characterized in that: Supplying air into the combustion chamber comprises: supplying primary air and secondary air into the combustion chamber in sequence; Before supplying primary air into the combustion chamber, a first gas is added to the primary air. The proportion of the first gas after mixing with the primary air is in the range of thirty percent to forty percent. The first gas is the exhaust flue gas generated after full combustion and treatment inside the horizontal circulating fluidized bed boiler.

3. The method for producing white carbon black by burning rice husk according to claim 2, characterized in that: During the process of supplying the secondary air into the combustion chamber, part of the secondary air forms a disturbed airflow, the flow direction of the disturbed airflow is inclined downward in a direction away from the wall surface, and the airflow velocity is within a first flow velocity range.

4. The method for producing white carbon black by burning rice husk according to claim 1, characterized in that: In the first separation stage, the first product is collected in a sealed ash cooler disposed below the first separator. The method further includes: in the cooling stage, the ash cooler cools the first product.

5. The method for producing white carbon black by burning rice husk according to claim 1, characterized in that: The method further includes: supplying third air into the burnout chamber during the burnout stage, wherein the amount of the third air is in a range of 110% to 130% of a theoretical amount of combustion air required for burning the rice husk.

6. The method for producing white carbon black by burning rice husk according to claim 5, characterized in that: The method further comprises: In the second separation stage, a second product generated by the combustion of the first flue gas in the burnout chamber is collected by a second separator arranged downstream of the burnout chamber, the second product is collected in a return material device arranged below the second separator to form a return material, and the remaining second flue gas flows to an outlet flue; In the material return stage, the material return device conveys the material return to the combustion chamber.

7. A horizontal circulating fluidized bed boiler, characterized in that: The white carbon black is produced by the method for producing white carbon black by burning rice husks as described in any one of claims 1 to 6; The horizontal circulating fluidized bed boiler comprises: A combustion chamber, comprising a main combustion chamber and an auxiliary combustion chamber, wherein the upper end of the auxiliary combustion chamber is communicated with the upper end of the main combustion chamber; A burnout chamber, wherein the lower end of the burnout chamber is connected to the lower end of the auxiliary combustion chamber; A first separator, arranged below the auxiliary combustion chamber and the burnout chamber; An ash cooler is provided on the first separator, and the inlet of the ash cooler is communicated with the first separator; a second separator, connected to the upper end of the burnout chamber; A material return device is provided below the second separator, wherein the input end of the material return device is communicated with the second separator, and the output end of the material return device is communicated with the combustion chamber; an outlet flue, connected to the second separator; A tail shaft, wherein the tail shaft is connected to the outlet flue, and the flue gas flowing through the second separator enters the tail shaft through the outlet flue.

8. The horizontal circulating fluidized bed boiler according to claim 7, characterized in that: Also includes: The flue gas treatment mechanism is located downstream of the tail shaft and includes a deacidification tower, a bag filter and a fan; A chimney, used to discharge the exhaust flue gas treated by the flue gas treatment mechanism to the outdoors; The recirculation flue has an inlet connected to the downstream of the flue gas treatment mechanism and an outlet connected to the outlet of a primary fan that delivers primary air to the combustion chamber.

9. The horizontal circulating fluidized bed boiler according to claim 7, characterized in that: The first separator comprises a first smoke guide part and a second smoke guide part, smoke flows from top to bottom in the first smoke guide part, and smoke flows from bottom to top in the second smoke guide part. A first smoke baffle is arranged inside the first smoke guide part, and the first smoke baffle extends obliquely downward from the flue wall to the inside of the flue, and a second smoke baffle is arranged inside the second smoke guide part, and the second smoke baffle extends obliquely downward from the flue wall to the inside of the flue, Wherein, the number of the second smoke baffles is greater than the number of the first smoke baffles.

10. The horizontal circulating fluidized bed boiler according to claim 7, characterized in that: The main combustion chamber comprises a gasification zone and a combustion zone, and a refractory material layer is laid on the water-cooled wall of the gasification zone.

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