Sugar mill mud calcination treatment system, treatment method and application

Abstract

The application provides a sugar factory filter mud roasting treatment system, a treatment method and application, and belongs to the technical field of sugar factory filter mud treatment. The sugar factory filter mud roasting treatment system provided by the application comprises a drying system, a roasting system and a dust removal system. The application provides a sugar factory filter mud roasting treatment method based on the system, and a roasting product is prepared by using sugar factory filter mud. The roasting product provided by the application is a renewable material, and can be applied to sugar beet sugar production, sugar cane sugar production (carbonic acid method), raw sugar processing and cleaning process, partially replaces lime, significantly reduces the amount of lime used in sugar factories, and plays a role in saving lime and reducing the pressure of the full equipment in the cleaning process in the sugar production process.

Description

Technical Field

[0001] This invention belongs to the field of sugar mill filter mud treatment technology, specifically relating to a sugar mill filter mud roasting treatment system, treatment method and application. Background Technology

[0002] Sugar mills primarily employ the carbonated sugar juice purification process, which involves adding approximately 1.8%–2.5% CaO twice (pre-ashing and main ashing) to the extract to coagulate, precipitate, and decompose proteins, colloids, and other non-sugar components. After two saturation reactions with CO2, CaCO3 particles are formed, acting as adsorbents and a filter framework for the proteins and other colloidal non-sugar components in the extract. This results in filter mud. The carbonated sugar juice purification process inevitably generates a large amount of sugar-refining filter mud, a major waste product of the sugar industry, primarily composed of CaCO3. Besides occupying significant land and incurring high environmental landfill costs, the filter mud, containing various organic matter and sugars, is highly susceptible to mold and foul odors, breeding harmful substances and significantly impacting soil and water resources. Furthermore, after dehydration, the sugar-refining filter mud typically consists of fine particles of 5–30 micrometers, easily dispersed in the atmosphere, severely affecting air quality.

[0003] Currently, the main methods for treating and utilizing filter mud from the carbonated sugar refining process include: 1. Simple landfilling, which occupies a large area of ​​land and causes serious environmental pollution, leading to soil alkalization and hardening; 2. Using the filter mud to produce industrial products such as cement and glass, but the presence of organic matter and the characteristics of its powder form limit its industrial application; 3. Utilizing its alkaline properties to improve acidic soil, but the uneven geographical distribution of acidic soil necessitates significant transportation costs; 4. Adding other raw materials (such as alcohol waste liquid, cassava residue, etc.) or nutrients to produce organic compound fertilizer, but this is currently limited to the laboratory stage and lacks feasibility for industrial-scale treatment. To date, the industrial utilization of sugar mill filter mud is limited, and there is still no thorough and effective treatment method for it, seriously affecting and restricting the healthy, rapid, and sustainable development of the sugar industry, becoming a major challenge facing the industry. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of this invention is to provide a sugar mill filter mud roasting treatment system and a sugar mill filter mud roasting treatment method, which can prepare sugar mill filter mud into calcium carbonate particles with high surface activity and regenerate it for use in the sugar purification process to replace lime.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a sugar mill filter mud roasting treatment system, including a drying system, a roasting system and a dust removal system;

[0007] The drying system includes a closed feeding device (1), a hammer dryer (2), and a high-temperature fan (17). The inlet of the hammer dryer (2) is connected to the outlet of the closed feeding device (1) and the exhaust port of the second cyclone separator (7). The outlet of the hammer dryer (2) is connected to the inlet of the first cyclone separator (3). The high-temperature fan (17) is connected between the inlet of the hammer dryer (2) and the exhaust port of the second cyclone separator (7).

[0008] The roasting system includes a first cyclone separator (3), a primary preheating device (4), a secondary preheating device (5), a roasting device (6), a second cyclone separator (7), a first cooling device (8), a second cooling device (9), a third cooling device (10), an SCR reactor (13), and a high-temperature axial flow fan (15); the exhaust port of the first cyclone separator (3) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the primary preheating device (4); the exhaust port of the primary preheating device (4) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the secondary preheating device (5); the exhaust port of the secondary preheating device (5) is connected to the inlet of the primary preheating device (4), and the discharge port is connected to the inlet of the roasting device (6); the roasting The calcining device (6) is connected to the second cyclone separator (7) via a gooseneck tube; the exhaust port of the second cyclone separator (7) is connected to the air inlet of the second preheating device (5) and the air inlet of the hammer dryer (2), and the discharge port is connected to the feed inlet of the first cooling device (8); the discharge port of the first cooling device (8) is connected to the feed inlet of the second cooling device (9), and the exhaust port is connected to the air inlet of the calcining device (6) via a high-temperature axial flow fan (15); the discharge port of the second cooling device (9) is connected to the feed inlet of the third cooling device (10), and the exhaust port is connected to the air inlet of the first cooling device (8); the discharge port of the third cooling device (10) is connected to the product silo (11); the air outlets of the first cyclone separator (3) and the first-stage preheating device (4) are equipped with SCR reactors (13);

[0009] The dust removal system includes a bag filter (12), an induced draft fan (16), and a smoke exhaust device (14); the air outlet of the bag filter (12) is connected to the smoke exhaust device (14) through the induced draft fan (16); the discharge port of the bag filter (12) is connected to the product silo (11).

[0010] The present invention also provides a method for roasting sugar mill filter mud based on the above-mentioned sugar mill filter mud roasting treatment system, comprising the following steps: the sugar mill filter mud and hot air enter a hammer dryer in the same direction for drying to obtain dried material; the dried material is separated by cyclone separation to obtain filter mud powder; the filter mud powder is subjected to primary preheating treatment, secondary preheating treatment, and roasting; the roasting product is separated by cyclone separation and cooled to obtain roasted product.

[0011] Preferably, the calcination temperature is 750–800°C and the calcination time is 6–8 seconds.

[0012] Preferably, the moisture content of the sugar mill filter mud is 45-60%, the hot air temperature is 700-750℃, and the dried material is a solid gas at 105-110℃.

[0013] Preferably, the moisture content of the filter mud powder is 1-2%, and the temperature is 103-105℃.

[0014] Preferably, the temperature of the filter mud powder after the first preheating treatment is 200-240℃; the temperature of the filter mud powder after the second preheating treatment is 420-470℃; the temperature of the calcined product is 740-760℃; and the temperature of the calcined product is 100-125℃.

[0015] The present invention also provides roasted products prepared by the above-mentioned sugar mill filter mud roasting treatment method.

[0016] The present invention also provides the application of the above-mentioned roasted product in the sugar purification process, wherein the roasted product partially replaces lime.

[0017] The present invention also provides the application of the above-mentioned roasted product in the preparation of products for sugar purification processes.

[0018] Preferably, the sugar purification process includes a beet sugar purification process, a carbonated sugarcane sugar purification process, and a raw sugar processing purification process.

[0019] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0020] This invention integrates the drying, roasting, and cooling of sugar mill filter mud into a series of unified processes, with the entire device being sealed. Based on production capacity, during operation, the roasting furnace, preheater, cooler, and cyclone separator are designed for coupled control (temperature, pressure, airflow, etc.), ensuring fluidized material flow without accumulation and achieving balanced and stable airflow, velocity, temperature, and material composition. This invention utilizes roasting to treat sugar mill filter mud, resulting in highly dispersed filter mud particles, adsorbed colloids, and moisture in the hot airflow. Mass and heat transfer are extremely rapid, with virtually no overheating or underheating, facilitating thermal stability and balance at each processing stage. This allows for stable and continuous production conditions while ensuring a dust-free process and preventing leakage of incomplete combustion products of organic matter, resulting in a favorable operating environment.

[0021] The sugar mill filter mud roasting treatment method described in this invention can greatly reduce the amount of sugar mill filter mud discharged, which is beneficial to environmental improvement. The roasted products obtained can be used as recycled materials in the sugar refining cleaning process (beet sugar refining cleaning process, carbonated sugarcane sugar refining cleaning process, and raw sugar processing cleaning process), partially replacing lime. The amount of lime used is reduced from 1.8-2.5% to 0.8-1.0%, and the corresponding CO2 saturation is reduced, which can achieve the effects of saving lime and greatly reducing the pressure on the saturation equipment in the sugar refining cleaning process. Attached Figure Description

[0022] Figure 1 Schematic diagram of a sugar mill filter mud roasting treatment system;

[0023] Figure 2 Scanning electron microscopy observation results of roasted products.

[0024] Figure 1 In the diagram, the components are: 1. Closed feeding device, 2. Hammer dryer, 3. First cyclone separator, 4. Primary preheating device, 5. Secondary preheating device, 6. Calcination device, 7. Second cyclone separator, 8. First cooling device, 9. Second cooling device, 10. Third cooling device, 11. Product silo, 12. Bag filter dust collector, 13. SCR reactor, 14. Exhaust system, 15. High-temperature axial flow fan, 16. Exhaust fan, and 17. High-temperature fan. Dashed lines indicate the laying of gas pipelines and the direction of gas transport; solid lines indicate the laying of material (solid) pipelines and the direction of material transport. Detailed Implementation

[0025] This invention provides a sugar factory filter mud roasting treatment system, such as... Figure 1 As shown, it includes a drying system, a roasting system, and a dust removal system;

[0026] The drying system includes a closed feeding device (1), a hammer dryer (2), and a high-temperature fan (17). The inlet of the hammer dryer (2) is connected to the outlet of the closed feeding device (1) and the exhaust port of the second cyclone separator (7). The outlet of the hammer dryer (2) is connected to the inlet of the first cyclone separator (3). The high-temperature fan (17) is connected between the inlet of the hammer dryer (2) and the exhaust port of the second cyclone separator (7). The high-temperature fan (17) is located close to the inlet of the hammer dryer (2).

[0027] The roasting system includes a first cyclone separator (3), a primary preheating device (4), a secondary preheating device (5), a roasting device (6), a second cyclone separator (7), a first cooling device (8), a second cooling device (9), a third cooling device (10), an SCR reactor (13), and a high-temperature axial flow fan (15); the exhaust port of the first cyclone separator (3) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the primary preheating device (4); the exhaust port of the primary preheating device (4) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the secondary preheating device (5); the exhaust port of the secondary preheating device (5) is connected to the inlet of the primary preheating device (4), and the discharge port is connected to the inlet of the roasting device (6); the roasting The calcining device (6) is connected to the second cyclone separator (7) via a gooseneck tube; the exhaust port of the second cyclone separator (7) is connected to the air inlet of the second preheating device (5) and the air inlet of the hammer dryer (2), and the discharge port is connected to the feed inlet of the first cooling device (8); the discharge port of the first cooling device (8) is connected to the feed inlet of the second cooling device (9), and the exhaust port is connected to the air inlet of the calcining device (6) via a high-temperature axial flow fan (15); the discharge port of the second cooling device (9) is connected to the feed inlet of the third cooling device (10), and the exhaust port is connected to the air inlet of the first cooling device (8); the discharge port of the third cooling device (10) is connected to the product silo (11); the air outlets of the first cyclone separator (3) and the first-stage preheating device (4) are equipped with SCR reactors (13);

[0028] The dust removal system includes a bag filter (12), an induced draft fan (16), and a smoke exhaust device (14); the air outlet of the bag filter (12) is connected to the smoke exhaust device (14) through the induced draft fan (16); the discharge port of the bag filter (12) is connected to the product silo (11).

[0029] In this invention, an SCR reactor (13) is installed at the outlet of the first cyclone separator (3) and the first-stage preheating device (4). Nitrogen-containing flue gas enters the SCR reactor, where, under the action of a catalyst, nitrogen oxides in the flue gas are reduced to N2 and H2O, achieving denitrification. The denitrified gas then enters the bag filter (12), reducing nitrogen oxide emissions to <50 mg / Nm³. 3 In order to avoid environmental pollution.

[0030] The bottom of the roasting apparatus (6) of the present invention preferably has a powder falling temporary storage and removal device.

[0031] The closed feeding device, hammer dryer, cyclone separator (first cyclone separator and second cyclone separator), preheating device (first preheating device and second preheating device), calcining device, cooling device (first cooling device, second cooling device and third cooling device), product silo, bag filter, induced draft fan, SCR reactor, high-temperature axial flow fan and high-temperature fan used in the system of the present invention can be commonly used devices in the art. Preferably, the closed feeding device of the present invention is a box feeder; the hammer dryer of the present invention is a hammer dryer; the cyclone separator of the present invention is a cyclone separator; the preheating device of the present invention is a suspension preheater; the calcining device of the present invention is a dispersed calcining furnace (suspension calcining furnace); and the cooling device of the present invention is a cyclone cooler.

[0032] Preferably, air cannons are installed at the lower part of the first cyclone separator and the lower part of the first-stage preheater in this invention to avoid material accumulation and stabilize continuous production conditions. This also ensures that the entire production process is free of dust and leakage of incomplete combustion products of organic matter, resulting in a good operating environment. In this system, the material leg in the connecting pipe between the material and the airflow is preferably a V-valve material leg, and a stabilizer is added to the V-valve material leg to prevent short-circuiting between the airflow and the material flow. This ensures that the airflow and material flow in the system follow the designed route for sufficient heat exchange, improving the system's thermal efficiency and operational stability.

[0033] The present invention also provides a method for roasting sugar mill filter mud based on the above-mentioned sugar mill filter mud roasting treatment system, comprising the following steps: the sugar mill filter mud and hot air enter a hammer dryer in the same direction for drying to obtain dried material; the dried material is separated by cyclone separation to obtain filter mud powder; the filter mud powder is subjected to primary preheating treatment, secondary preheating treatment, and roasting; the roasting product is separated by cyclone separation and cooled to obtain roasted product.

[0034] This invention involves drying sugar mill filter mud and hot air simultaneously in a hammer mill dryer to obtain dried material. The sugar mill filter mud has a moisture content of 45-60%, preferably 50-55%, and the hot air temperature is 700-750℃, preferably 720-740℃. The sugar mill filter mud enters the hammer mill dryer through a closed feeding device (outlet), while the hot air enters simultaneously with the filter mud through a hot air inlet pipe. The hot air and filter mud fully contact and exchange heat in the mixing chamber of the hammer mill dryer. The hammers disperse the filter mud particles in the mixed gas, suspending them in the gas to form a uniform material curtain, rapidly drying the moisture in the filter mud to obtain dried material, i.e., dried material containing solids at 105-110℃. The hot air is preferably from the hot flue gas separated by cyclone separation after roasting, pressurized by a high-temperature fan, and then enters the hammer mill dryer simultaneously with the filter mud through the hot air inlet pipe.

[0035] The material to be dried in this invention enters the inlet of the first cyclone separator through the outlet of the hammer dryer. The cyclone separator separates the material into solid and gaseous components. The solid material undergoes preheating treatment. The gaseous material (containing dust) is conveyed to a bag filter, where the dust is collected and then discharged into the atmosphere. The gas outlet of the first cyclone separator in this invention contains moist gas (gaseous material) at a temperature of 105–110°C. The solid material (filter mud powder) in this invention has a moisture content of 1–2% and a temperature of 103–105°C.

[0036] The dried solid material (filter mud powder) undergoes a two-stage preheating treatment. The first-stage preheating process, as described in this invention, involves a temperature of 400℃, a pressure difference of 3.2 Pa, and a processing time of 4 seconds. This first-stage preheating increases the temperature of the filter mud powder, preventing the formation of incomplete decomposition products such as protein colloids, which could agglomerate the material and obstruct the operating space. The second-stage preheating process, as described in this invention, involves a temperature of 600℃, a pressure difference of 3.4 Pa, and a processing time of 4 seconds. The temperature of the filter mud powder after the first-stage preheating is 200–240℃; the temperature after the second-stage preheating is 420–470℃; and the temperature of the roasting gas flow is 740–760℃. The heat source for the second-stage preheating is preferably the hot flue gas separated by the second cyclone separator after roasting. The gas after the second-stage preheating is then discharged back into the first-stage preheating device for reuse. The gas after the first-stage preheating is also transported to a bag filter dust collector, where the powder is collected before being released into the atmosphere. Preferably, the gas after the first-stage preheating treatment is subjected to denitrification treatment through an SCR reactor.

[0037] The preheated solid material enters the roasting furnace for suspension roasting. The roasting temperature is 750–800℃, preferably 760–780℃; the roasting time is 6–8 seconds, preferably 7 seconds. During roasting, furnace gas enters the roasting furnace from the bottom, gradually feeding in the preheated solid material. The solid material is uniformly suspended and highly dispersed in the jetting airflow. Simultaneously, fuels such as natural gas or heavy oil and combustion air burn in the furnace to generate heat energy (a pulsed ignition mechanism is set opposite to the fuel nozzles to prevent flameout). The airflow carries the material upward, completing processes such as combustion, heat transfer, decomposition, and mass transfer. The mass and heat transfer efficiency is greatly improved compared to the stacked state calcination, increasing the reaction rate and thermal efficiency. This process achieves the desorption of colloids and proteins originally adsorbed by the sugar mill filter mud from the calcium carbonate surface through roasting and carbonization, thereby preparing calcium carbonate particles that can regain their adsorption function.

[0038] After roasting, the hot gas stream carrying the material is introduced into a cyclone separator through a gooseneck tube. Part of the separated and collected hot gas stream is used as a drying heat source in a hammer dryer, and the other part is used as a preheating heat source in a secondary preheating unit to preheat the material before roasting. After roasting, nitrogen-containing flue gas is generated. The nitrogen-containing flue gas passes through a secondary preheating unit, a primary preheating unit, and an SCR reactor, and is discharged after denitrification.

[0039] In this invention, the roasted product enters a cooling device for temperature reduction, passing through a three-stage cooling system where it is gradually cooled by external air to obtain a roasted product with a temperature of 100–125°C, which then enters the finished product silo. The powder collected by the bag filter dust collector also enters the finished product silo.

[0040] The roasted product (i.e., recycled sugar mill filter mud product) prepared by this invention is mainly composed of fine calcite (calcium carbonate) particles. The composition and mass percentage indicators are: CaCO3 > 95%, organic matter (protein, sugar, pectin, pectic acid, etc.) 0.0%, MgO 2-4%, SiO2 2-3%, Al2O3 0.2-0.3%, with a particle diameter ranging from 5 to 25 μm, and 70% of the particles having a diameter < 10 μm. This invention eliminates the colloids and other substances originally adsorbed on the surface of the calcium carbonate particles, reducing the surface energy. Under suitable alkalinity (under carbonation process conditions), the surface of the calcium carbonate particles also has a strong ability to accumulate various dissolved substances—adsorption capacity; moreover, the particle structure is stable, making it effective as an adsorption carrier and filter framework for colloids in sugar juice without increasing viscosity. The roasted product prepared by this invention can effectively adsorb proteins, colloids, calcium oxalate, calcium citrate, and calcium tartrate.

[0041] This invention also provides the application of the above-mentioned roasted product in the sugar refining purification process, whereby the roasted product partially replaces lime. The sugar refining purification process is preferably a dual-carbon refining process, which includes a beet sugar refining purification process, a carbonated sugarcane sugar refining purification process, and a raw sugar processing purification process. When the roasted product of this invention is added at 0.8–1.2 wt% (to sugar juice), it can achieve a "positive correlation" with lime substitution, reducing the lime usage in sugar mills from the traditional 1.8–2.5% to 0.8–1.0%, while correspondingly reducing saturated CO2. This achieves the effects of saving lime and significantly reducing the pressure on saturated equipment in the sugar refining purification process.

[0042] This invention also provides the application of the above-mentioned roasted products in the preparation of products for sugar refining purification processes. The sugar refining purification process is preferably a dual-carbon sugar refining purification process, which includes a beet sugar refining purification process, a carbonated sugarcane sugar refining purification process, and a raw sugar processing purification process. The calcium carbonate particle size of the sugar mill filter mud roasted products obtained by this invention using the suspension roasting principle varies from microparticles to micropowder. Because it eliminates the colloids and other substances originally adsorbed on the surface of the calcium carbonate particles, it reduces the surface energy. Under suitable alkalinity (carbonized process conditions), the surface of its calcium carbonate particles also has a strong ability to accumulate insoluble substances and certain macromolecular soluble substances, i.e., it possesses adsorption capacity; moreover, the particle structure is stable, and it can be effectively used as an adsorption carrier and filter framework for colloids in sugar juice without increasing viscosity.

[0043] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] In a specific embodiment of the present invention, the raw material—sugar factory filter mud—is beet sugar factory filter mud, with the following composition and mass percentage: CaCO3 78-82%, organic matter (protein, sugar, pectin, pectic acid, etc.) 11-13%, MgO 3-5%, SiO2 2-3%, Al2O3 0.2-0.3%, and other components 0.2-0.3%. The powder particle diameter is in the range of 5-30 μm, with 65% of the particles having a diameter <10 μm.

[0045] Unless otherwise specified, the following embodiments are all conventional methods.

[0046] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0047] Example 1

[0048] A sugar mill filter mud roasting treatment system, such as Figure 1 As shown in the figure (dashed lines indicate the laying of gas pipelines and the direction of gas transportation, and solid lines indicate the laying of material (solid) pipelines and the direction of material transportation), it includes a drying system, a roasting system, and a dust removal system;

[0049] The drying system includes a closed feeding device (1), a hammer dryer (2), and a high-temperature fan (17). The inlet of the hammer dryer (2) is connected to the outlet of the closed feeding device (1). The inlet of the hammer dryer (2) is connected to the exhaust port of the second cyclone separator (7) through the high-temperature fan (17). The outlet of the hammer dryer (2) is connected to the inlet of the first cyclone separator (3). The high-temperature fan (17) is located close to the inlet of the hammer dryer (2).

[0050] The roasting system includes a first cyclone separator (3), a primary preheating device (4), a secondary preheating device (5), a roasting device (6), a second cyclone separator (7), a first cooling device (8), a second cooling device (9), a third cooling device (10), an SCR reactor (13), and a high-temperature axial flow fan (15); the exhaust port of the first cyclone separator (3) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the primary preheating device (4); the exhaust port of the primary preheating device (4) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the secondary preheating device (5); the exhaust port of the secondary preheating device (5) is connected to the inlet of the primary preheating device (4), and the discharge port is connected to the inlet of the roasting device (6); the roasting The calcining device (6) is connected to the second cyclone separator (7) via a gooseneck tube; the exhaust port of the second cyclone separator (7) is connected to the air inlet of the second preheating device (5) and the air inlet of the hammer dryer (2), and the discharge port is connected to the feed inlet of the first cooling device (8); the discharge port of the first cooling device (8) is connected to the feed inlet of the second cooling device (9), and the exhaust port is connected to the air inlet of the calcining device (6) via a high-temperature axial flow fan (15); the discharge port of the second cooling device (9) is connected to the feed inlet of the third cooling device (10), and the exhaust port is connected to the air inlet of the first cooling device (8); the discharge port of the third cooling device (10) is connected to the product silo (11); the air outlets of the first cyclone separator (3) and the first-stage preheating device (4) are equipped with SCR reactors (13);

[0051] The dust removal system includes a bag filter (12), an induced draft fan (16), and a smoke exhaust device (14); the air outlet of the bag filter (12) is connected to the smoke exhaust device (14) through the induced draft fan (16); the discharge port of the bag filter (12) is connected to the product silo (11).

[0052] The closed feeding device is a box-type feeder; the hammer drying device is a hammer dryer; the first cyclone separator and the second cyclone separator are cyclone separators; the preheating device is a suspension preheater; the roasting device is a dispersed roasting furnace (suspension roasting furnace); and the cooling device is a cyclone cooler.

[0053] Example 2

[0054] 1. Method for roasting filter mud in beet sugar factories (based on the system in Example 1):

[0055] (1) Drying

[0056] Raw material – sugar mill filter mud (moisture content 45-60%) – enters the hammer dryer in the same direction as 750℃ hot air. The hot airflow and the sugar mill filter mud fully contact and exchange heat in the mixing chamber. The hammers break up the sugar mill filter mud particles in the mixed gas, suspending them in the mixed gas to form a uniform material curtain, resulting in a solid-containing gas at 105-110℃, which is the dried material (moisture content ≤1%). The required hot air comes from the flue gas of the roasting furnace.

[0057] (2) Calcination

[0058] The dried material enters the first cyclone separator. The gas outlet of the first cyclone separator is humid gas at 105-110℃. After the material powder is collected by a bag filter, it is discharged into the atmosphere. The solid outlet is filter mud powder with a moisture content of 1-2% and a temperature of 103-105℃. The filter mud powder is then preheated and calcined.

[0059] Table 1 Preheating and calcination parameter settings

[0060] Level 1 preheating Secondary preheating roaster Dwell time (seconds) 4 4 7 Average temperature ℃ 220 450 750 highest temperature 400 600 800 Pressure difference kPa 3.2 3.4 4.5-6.5

[0061] After roasting, the hot airflow carrying the material is introduced into a cyclone separator through a gooseneck tube to separate the roasted product. The solid material enters a cooling device to cool down and passes through a three-stage cooling device, gradually cooled by external air, to obtain roasted products with a temperature of 100-125℃, which then enter the finished product warehouse.

[0062] Table 2 Cooling Condition Parameter Settings

[0063]

[0064] 2. Analysis of roasted products

[0065] (1) XRD analysis showed that the structure of the roasted product is shown in Table 3.

[0066] Table 3 Structure of roasted products

[0067] Phase name calcite quartz Calcium oxalate stone Hematite ％ 97.7 0.8 0.4 1.1

[0068] Observation using scanning electron microscopy revealed that the calcined product was mainly composed of fine calcite (calcium carbonate) particles, as shown in the results. Figure 2 As shown.

[0069] (2) The roasting times were set to 4s, 6s, 8s, 10s, 12s, 14s, and 19s respectively, with the other conditions the same as in step 1. Water was added to each group of roasted products and stirred for 5 minutes to obtain a 10% concentration sample. The protein and colloid content in the sample was then tested. The results are shown in Table 4.

[0070] Table 4 Protein and colloid content of roasted products

[0071] Calcination time (seconds) 4 6 8 10 12 14 19 protein% 0.01 0.001 0.000 0.000 0.000 0.000 0.000 colloid% 0.008 0.000 0.000 0.000 0.000 0.000 0.000

[0072] Conclusion: When the calcination time reaches 6 seconds or more, the colloids are completely calcined.

[0073] Experimental Example 1

[0074] Application of the calcined product prepared in step 1 of Example 2 (industrial laboratory simulation practice):

[0075] 1. Determine the adsorption rate of various substances in sugar juice by roasted products.

[0076] (1) Determination of colloid content: Accurately weigh 1g of filter mud sample into a 100mL beaker, add 30mL of 1mol / L HCl, stir thoroughly to dissolve the sample, and make up to 100mL in a volumetric flask. Take 10mL from the flask into a 50mL centrifuge tube, add 35mL of 75% ethanol, incubate at 85℃ for 10min, cool, and then add anhydrous ethanol to make the volume reach 50mL. Centrifuge at 4000r / min for 15min, discard the supernatant, wash the precipitate, and make up to 100mL in a volumetric flask. Add 5mL of 1mol / L NaOH, let stand for 15min, shake well, and take 1mL of the solution into a 25mL test tube. Repeat the above steps. Measure three times and take the average value. The formula for pectin calculation is: T=C×V×G;

[0077] Where C = (y + 0.001) / 0.0091 is the galacturonic acid concentration, in mg / L;

[0078] V = 1, which is the total volume of 1g sample diluted, in liters (L).

[0079] G represents the total weight of the sample, in grams.

[0080] T represents the weight of the colloid, in mg.

[0081] (2) Protein determination method: Kjeldahl method was used.

[0082] (3) The determination of calcium oxalate is carried out by titration: the calcium oxalate solution is titrated with dilute nitric acid or dilute hydrochloric acid until the oxalic acid solution is completely converted into oxalate ions. Ethylenediaminetetraacetic acid (EDTA) is used as a complexing agent to form a colorless complex with calcium. Methylene blue is added as an indicator (the indicator solution changes from blue to red). The titration continues until the indicator endpoint is reached. The calcium content in calcium oxalate can be calculated from the volume of EDTA solution consumed in the titration.

[0083] (4) Calcium citrate was determined according to the determination method in GB1903.14—2016.

[0084] (5) Determination of calcium tartrate by colorimetric spectrophotometry: First, prepare a standard solution and calibrate a standard curve based on the absorbance value; then measure the absorbance value of the sample and compare it with the standard curve to determine the content.

[0085] Experimental procedure (simulating various non-sugar components in beet sugar juice, and measuring the adsorption effect of roasted products on them):

[0086] Take five 250mL beakers, add 5.2g of the roasted product to each beaker, add 200mL of distilled water (approximately 2.6% concentration), and adjust the pH to 11 with sodium hydroxide. Add protein, colloid, calcium oxalate, calcium citrate, and calcium tartrate to each beaker according to the proportions in Table 5, stir, and let stand for 5 minutes. Then add hydrochloric acid to adjust the pH to 7.5, maintain the temperature at 40℃, filter each beaker, and collect the filtrate. Determine the content of protein, colloid, calcium oxalate, calcium citrate, and calcium tartrate in each filtrate, and calculate the removal rate. The results are shown in Table 5.

[0087] Table 5 Adsorption rates of various substances in roasted products

[0088] protein colloid Calcium oxalate Calcium citrate Calcium tartrate Add to% 0.4 0.6 0.06 0.06 0.06 Filtered juice % 0.09 0.16 0.023 0.025 0.022 Removal rate % 77.5 73.3 61.6 58.3 63.3

[0089] The results show that the roasted product obtained by the present invention has a strong adsorption effect on proteins, colloids, calcium oxalate, calcium citrate, calcium tartrate and other substances contained in sugar syrup.

[0090] 2. Adsorption filtration experiment verification:

[0091] (1) Treating the substrate:

[0092] The substrates are as follows: pre-ash juice from the sugar refining cleaning process, with a purity of 87.55% and an alkalinity of 0.18, indicating that 100 ml contains 0.18 grams of alkaline substances (represented by CaO), and a pH of 11.0; lime milk, 20.0 Be (CaO with a weight concentration of 17.72%); and roasted products, designated as A (calcium carbonate content of 95.5%, with a particle size distribution of 95% from 5 to 20 micrometers).

[0093] (2) Experimental steps:

[0094] Take 2000 mL of pre-lye juice from the sugar beet cleaning process, add lime milk and roasted product (A) according to Table 6 respectively, experimental temperature: 40℃, stir and let stand for 10 min. Then (1) filter: pour into a suction filter (double layer filter paper) for filtration, record the filtration time, purity of the filtrate and colloidal content (converted degumming rate); (2) saturate with CO2 in a self-made saturation device to pH=7.5, filter: pour into a suction filter (double layer filter paper) for filtration, record the filtration time, purity of the filtrate and colloidal content (converted degumming rate); the records are as follows:

[0095] Table 6 Adsorption rates of various substances in roasted products

[0096]

[0097]

[0098] Conclusion: Under the current dual-carbon purification process in sugar beet production, the roasted filter mud of this invention exhibits strong adsorption of non-sugar components such as colloids in sugar juice. Adding 0.8–1.2% (for sugar beets) of the roasted filter mud of this invention can achieve a "positive substitution correlation," correspondingly reducing the amount of ash added in the sugar purification process by 0.5–0.8% without reducing purification efficiency or decolloid removal effect. Adding 1.2–2.0% (for sugar beets) of the roasted filter mud of this invention can correspondingly reduce the amount of ash added in the sugar purification process by 0.8–1.2% without reducing purification efficiency or decolloid removal effect.

[0099] When adding the roasted sugar mill filter mud of this invention, if the total ash addition during the simulated cleaning process is less than 0.8%, both the degumming rate and the purity of the filtered juice will decrease; if the total ash addition is less than 0.6%, both the degumming rate and the purity of the filtered juice will decrease significantly. In beet sugar production, a minimum ash addition of 0.6% to 0.8% (for beets) must be maintained when adding the roasted product.

[0100] Application Example 1

[0101] Adding roasted products during the sugar beet purification process (roasted products prepared in step 1 of Example 2):

[0102] Based on the original sugar beet purification process, 1% (for sugar beets) of lime (CaO) is added to the cold ash tank in the carbonated sugar juice purification process for roasted products. Simultaneously, while ensuring purification efficiency and degumming rate of the sugar juice, the amount of lime (CaO) added in the original process is reduced by 0.6%. The calcium carbonate particles on the surface of the roasted products adsorb non-sugar components from the sugar juice and act as a filter support framework, thus improving the filtration process. This replaces the amount of lime (CaO) required in the original process for adsorbing non-sugar components from the sugar juice on the surface of the calcium carbonate particles and for acting as a filter support framework.

[0103] To prevent dust from calcining the products, a powder metering conveyor and a mixer are installed: a portion of the main ash juice from the sugar refining and cleaning process is extracted and neutralized with the sugar mill filter mud from the calcined products of this invention, with a neutralization concentration of 20-30%.

[0104] Application Example 2

[0105] Adding roasted products during the sugar beet purification process (roasted products prepared in step 1 of Example 2):

[0106] Based on the original sugar beet purification process, 1.2% (for sugar beets) of lime (CaO) is added at the end of the pre-asher stage of the carbonated sugar juice purification process for roasted products. Simultaneously, while ensuring purification efficiency and degumming rate of the sugar juice, the amount of lime (CaO) added in the original process is reduced by 0.8%. The calcium carbonate particles on the surface of the roasted products adsorb non-sugar components from the sugar juice and act as a filter support framework, thus improving the filtration process. This replaces the amount of lime (CaO) required in the original process for adsorbing non-sugar components from the sugar juice on the surface of the calcium carbonate particles and for acting as a filter support framework.

[0107] The process maintains low-alkalinity ash and saturated carbon CO2, preventing the formation of viscous, gel-like sucrose calcium carbonate and stabilizing the sugar production process.

[0108] Application Example 3

[0109] Raw sugar processing and addition to roasted products (roasted products prepared in step 1 of Example 2):

[0110] Raw sugar is a crude sugar product obtained from the initial processing of sugarcane at its production site. It cannot be directly used in the food and sugar products industry and must be refined into edible white sugar. Raw sugar processing employs a carbon purification process: raw sugar dissolution – addition of lime – CO2 saturation – filtration – crystallization – centrifugation – drying – white sugar. This process removes non-sugar components from the raw sugar, resulting in high-purity white sugar. The raw sugar concentration is 55-60%, with 1% lime added (to the raw sugar). The lime addition method is instantaneous, using an lime mixer at the inlet of a carbon saturation tank to shorten the high-alkali reaction time, achieving simultaneous lime saturation, precipitation (calcium carbonate particles) adsorption of non-sugar components, and filtration to remove non-sugar components from the raw sugar.

[0111] While maintaining the original process, a new method is adopted where, during the raw sugar dissolution stage, roasted products are added to the raw sugar dissolution tank via a powder metering conveyor, along with the hot water for sugar dissolution and stirring. Based on the raw sugar mass, 0.4% of the roasted products (to the raw sugar) are added, while simultaneously reducing ash content by 0.2%. The calcium carbonate particles in the roasted products adsorb non-sugar components from the dissolved sugar juice and act as a filter support framework to improve the filtration process. This replaces the amount of lime (CaO) required in the original process for adsorbing non-sugar components from the dissolved sugar juice and serving as a filter support framework. The amount of lime (CaO) added is reduced accordingly while ensuring the cleaning efficiency of the raw sugar processing and the impurity removal rate of the sugar juice. After filtration, non-sugar components from the raw sugar are removed.

[0112] Application Example 4

[0113] Raw sugar processing and addition to roasted products (roasted products prepared in step 1 of Example 2):

[0114] Raw sugar is a crude sugar product obtained from the initial processing of sugarcane at its production site. It cannot be directly used in the food and sugar products industry and must be refined into edible white sugar. Raw sugar processing employs a carbon purification process: raw sugar dissolution – addition of lime – CO2 saturation – filtration – crystallization – centrifugation – drying – white sugar. This process removes non-sugar components from the raw sugar, resulting in high-purity white sugar. The raw sugar concentration is 55-60%, with 1% lime added (to the raw sugar). The lime addition method is instantaneous, using an lime mixer at the inlet of a carbon saturation tank to shorten the high-alkali reaction time, achieving simultaneous lime saturation, precipitation (calcium carbonate particles) adsorption of non-sugar components, and filtration to remove non-sugar components from the raw sugar.

[0115] While maintaining the original process, a new method is adopted where, during the raw sugar dissolution stage, roasted products are added to the raw sugar dissolution tank via a powder metering conveyor, along with the hot water for sugar dissolution and stirring. Based on the raw sugar mass, 0.5% of the roasted products (to the raw sugar) are added, while simultaneously reducing ash content by 0.3%. The calcium carbonate particles in the roasted products adsorb non-sugar components from the dissolved sugar juice and act as a filter support framework to improve the filtration process. This replaces the amount of lime (CaO) required in the original process for adsorbing non-sugar components from the dissolved sugar juice on the calcium carbonate particle surface and for acting as a filter support framework. The amount of lime (CaO) added is reduced accordingly while ensuring the cleaning efficiency of the raw sugar processing and the impurity removal rate of the sugar juice. After filtration, non-sugar components from the raw sugar are removed.

[0116] In summary, by rationally adding ingredients to the roasted products of this invention, combined with a reduction in the amount of lime (CaO) added, the original cleaning effect of the sugar-making cleaning process can be achieved.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A sugar factory filter mud roasting treatment system, characterized in that, Includes a drying system, a roasting system, and a dust removal system; The drying system includes a closed feeding device (1), a hammer dryer (2), and a high-temperature fan (17). The inlet of the hammer dryer (2) is connected to the outlet of the closed feeding device (1) and the exhaust port of the second cyclone separator (7). The outlet of the hammer dryer (2) is connected to the inlet of the first cyclone separator (3). The high-temperature fan (17) is connected between the inlet of the hammer dryer (2) and the exhaust port of the second cyclone separator (7). The roasting system includes a first cyclone separator (3), a primary preheating device (4), a secondary preheating device (5), a roasting device (6), a second cyclone separator (7), a first cooling device (8), a second cooling device (9), a third cooling device (10), an SCR reactor (13), and a high-temperature axial flow fan (15); the exhaust port of the first cyclone separator (3) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the primary preheating device (4); the exhaust port of the primary preheating device (4) is connected to the inlet of the bag filter (12), and the discharge port is connected to the inlet of the secondary preheating device (5); the exhaust port of the secondary preheating device (5) is connected to the inlet of the primary preheating device (4), and the discharge port is connected to the inlet of the roasting device (6); the roasting The calcining device (6) is connected to the second cyclone separator (7) via a gooseneck tube; the exhaust port of the second cyclone separator (7) is connected to the air inlet of the second preheating device (5) and the air inlet of the hammer dryer (2), and the discharge port is connected to the feed inlet of the first cooling device (8); the discharge port of the first cooling device (8) is connected to the feed inlet of the second cooling device (9), and the exhaust port is connected to the air inlet of the calcining device (6) via a high-temperature axial flow fan (15); the discharge port of the second cooling device (9) is connected to the feed inlet of the third cooling device (10), and the exhaust port is connected to the air inlet of the first cooling device (8); the discharge port of the third cooling device (10) is connected to the product silo (11); the air outlets of the first cyclone separator (3) and the first-stage preheating device (4) are equipped with SCR reactors (13); The dust removal system includes a bag filter (12), an induced draft fan (16), and a smoke exhaust device (14); the air outlet of the bag filter (12) is connected to the smoke exhaust device (14) through the induced draft fan (16); the discharge port of the bag filter (12) is connected to the product silo (11).

2. A method for roasting sugar mill filter mud based on the sugar mill filter mud roasting treatment system of claim 1, characterized in that, Includes the following steps: Sugar mill filter mud and hot air enter a hammer dryer in the same direction for drying to obtain dried material; The dried material is separated by cyclone separation to obtain filter mud powder; The filter mud powder undergoes primary preheating treatment, secondary preheating treatment, and calcination. The roasted product is separated by cyclone separation and cooled to obtain the roasted product.

3. The method for roasting sugar mill filter mud according to claim 2, characterized in that, The roasting temperature is 750–800℃, and the roasting time is 6–8 seconds.

4. The method for roasting sugar mill filter mud according to claim 2, characterized in that, The sugar mill filter mud has a moisture content of 45-60%, the hot air temperature is 700-750℃, and the dried material is a solid gas at 105-110℃.

5. The method for roasting sugar mill filter mud according to claim 2, characterized in that, The filter mud powder has a moisture content of 1-2% and a temperature of 103-105℃.

6. The method for roasting sugar mill filter mud according to claim 2, characterized in that, The temperature of the filter mud powder after the first-stage preheating treatment is 200-240℃; the temperature of the filter mud powder after the second-stage preheating treatment is 420-470℃; the temperature of the calcined product is 740-760℃; and the temperature of the calcined product is 100-125℃.

7. The roasted product prepared by the roasting treatment method for sugar mill filter mud according to any one of claims 2 to 6.

8. The application of the roasted product according to claim 7 in the sugar purification process, characterized in that, The roasted product is used to partially replace lime.

9. The use of the roasted product according to claim 7 in the preparation of products for sugar purification processes.

10. The application according to claim 8 or 9, characterized in that, The sugar purification process includes a beet sugar purification process, a carbonated sugarcane sugar purification process, and a raw sugar processing purification process.

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