Seaweed waste residue resource recycling method

Abstract

The invention relates to the technical field of comprehensive utilization of resources, in particular to a seaweed waste residue resource recycling method. The method is characterized in that the circulating fluidized bed boiler can also be regarded as an airflow crushing device, heat energy can be recycled by feeding the seaweed waste residues into the circulating fluidized bed boiler for combustion, silica ash residues can be recycled by airflow crushing in the combustion process, and high-activity, superfine and spherical mineral admixtures required by quick-hardening and high-strength Portland cement can be prepared by further performing high-speed airflow crushing. The designed circulating fluidized bed boiler for combusting the seaweed waste residues comprises a main circulation loop and a tail flue, the main circulation loop comprises a hearth, a gas-solid separator and a solid particle returning device, and solid particles are carried by airflow to complete first-stage low-speed airflow crushing and grading in the main circulation loop; and the solid particle returning device is provided with a high-speed airflow crusher and a differential classifier, and the solid particles are subjected to second-stage high-speed airflow crushing and classification at the high-speed airflow crusher and the differential classifier.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive utilization of resources, and particularly relates to a seaweed waste residue resource recycling method. BACKGROUND

[0002] Seaweed gum is a kind of food gum extracted from natural seaweed. Seaweed gum is derived from the extract of seaweed. Important commercial seaweed gums include carrageenan, agar, and agar from red algae. Agar and carrageenan, and alginate are the three most widely used seaweed gums in the world, and they have a wide range of applications in food industry, medical industry, daily chemical industry, and biological engineering. The main production processes of carrageenan include alkali treatment, washing, acidification and bleaching, gum extraction, gelation, cutting, freezing and drying, etc. The most commonly used method for gum extraction is constant temperature water bath extraction, and the extraction temperature is usually between 90-95℃. High temperature can promote the dissolution of seaweed, break down its internal fiber structure, accelerate the dissolution of internal gum, and improve the yield. The main equipment for providing heat is an industrial boiler. The most commonly used method for gelation is squeezing and filtering, and perlite filter aid is used to help the gum filter out, so during the production of carrageenan, perlite waste and insoluble fiber waste, called seaweed mud or seaweed waste, will be generated. The main components of perlite waste are SO2, Al2O3, CaO, K2O, Na2O, Fe2O3, and H2O, among which the mass ratio of SO2 is about 70%, the mass ratio of Al2O3 is about 12%, and the mass ratio of H2O is about 5%. Perlite is mainly composed of high content of amorphous spherical glass SO2, with very high fineness and large specific surface area, so it has high volcanic ash activity and can improve the early strength of concrete. Therefore, perlite is a commonly used mineral additive for early strength and high strength concrete, and the compressive strength and durability of concrete mixed with perlite are significantly improved. Therefore, the perlite filter material in seaweed waste is restored to activity after high-temperature calcination and ultra-fine grinding, and is mixed into high-C3S-content Portland cement clinker as a mineral additive, which is one of the methods for proportioning early strength and high strength Portland cement. SO2, as the acid anhydride of silicic acid, can also be directly used as a main component of Portland cement raw materials to produce cement clinker; insoluble fiber waste is mainly composed of red algal cell wall components, including cellulose, hemicellulose, lignin, chitosan, and plant wax. Insoluble fiber waste has the characteristics of high volatile matter, low ignition temperature, and fast combustion speed, but also has the characteristics of high incombustible inorganic matter content and low calorific value, and can be used as auxiliary fuel for industrial boilers. Chinese invention patent (patent number CN200810023832X, patent name Double-furnace structure circulating fluidized bed boiler) discloses a double-furnace structure circulating fluidized bed boiler, which is characterized by: it mainly includes a fluidized bed boiler body composed of water-cooled wall pipes and buried pipe heating surfaces to form a coal-fired furnace; a slot separator is arranged on the water-cooled wall pipe at the outlet of the coal-fired furnace; a convection tube bundle is arranged between the upper drum and the lower drum, a dust hopper is connected below the convection tube bundle, and an economizer is arranged below the lower drum; the feature is that a waste residue incineration furnace is arranged in front of the coal-fired furnace, and an incinerator air supply chamber is arranged on the waste residue incineration furnace; the waste residue incineration furnace is communicated with the coal-fired furnace. The waste residue incineration furnace is provided with a waste residue feeding port, a waste residue discharging port, and an incinerator air supply chamber.The present application simultaneously sets two furnaces, which respectively burn coal and low heat value waste residue, so that the waste residue is fully combusted; the ratio of coal and waste residue used by the boiler can be flexibly adjusted according to the amount of waste residue, and the coal combustion chamber can still normally operate even when the waste residue furnace is shut down, so as to ensure that the boiler supplies steam at full load. Chinese invention patent (patent number CN2004200117229, patent name high-efficiency waste residue boiler for glyoxal) discloses a high-efficiency waste residue boiler for glyoxal, which is characterized in that: a drying flue is additionally arranged at the outlet of the boiler flue gas, an electric material stirring device is arranged at the lower part of a flue ash separator at the end of the drying flue, a cyclone combustion device composed of a secondary air supply nozzle and a hot air wall is arranged in the furnace, water-cooled walls connected with upper and lower headers are arranged on the two side walls, and a wet desulfurization device arranged at the rear of an induced draft fan is combined to form the boiler. The boiler has the advantages of reasonable structure design, novel and unique concept, stable and reliable performance, reduced dust emission, reduced labor intensity, reduced air pollution, environmental protection, energy saving, increased efficiency, easy ash and wax removal, wide application prospect, economy and practicality, etc. The boiler is the most ideal waste residue boiler for glyoxal so far. Chinese invention patent (patent number CN901073369, patent name impact type air flow pulverizer and pulverizing method of powder) discloses an impact type air flow pulverizer and a pulverizing method of powder, which is characterized in that: an acceleration tube for conveying and accelerating powder by high-pressure gas, a pulverizing tube, and an impact part for pulverizing the powder sprayed from the acceleration tube by impact force are arranged, the impact part is arranged in a pulverizing chamber and opposite to the outlet of the acceleration chamber, a powder raw material feeding port is arranged on the acceleration tube, and a secondary air inlet is arranged between the powder raw material feeding port and the outlet of the acceleration tube. The acceleration tube has the shape of a Laval tube, the acceleration tube has the shape of an ejector, the raw material powder sent from a raw material powder feeding port is conveyed in the acceleration tube by high-pressure gas and accelerated, the powder is sprayed into the pulverizing chamber from the outlet of the acceleration tube, the powder collides with the opposite impact part to be pulverized, and the characteristic is that: a secondary air inlet is arranged between the raw material powder feeding port and the outlet of the acceleration tube, and the secondary air is introduced into the acceleration tube from the secondary air inlet. An impact type air flow pulverizer, an air flow classifier, a communication device for introducing the powder pulverized by the impact type air flow pulverizer into the air flow classifier, and another communication device for introducing the coarse powder classified by the air flow classifier together with the powder raw material into the impact type air flow pulverizer; the impact type air flow pulverizer is provided with an acceleration tube for conveying and accelerating the powder by high-pressure gas, a pulverizing chamber, and an impact part for pulverizing the pulverized material sprayed from the acceleration tube by impact force, the impact part is arranged in the pulverizing chamber and opposite to the outlet of the acceleration tube, and a powder raw material feeding port is arranged on the acceleration tube.

[0003] The prior art "circulating fluidized bed boiler with double furnace structure" aims to provide a boiler scheme for burning two kinds of fuel (coal and waste residue), the combustion nature is oxidation reaction, due to the difference of the fuel, the oxidation reaction rate is different, the air ratio concentration is different, the continuous combustion conditions are different, since the combustion temperature is the main means to control the combustion process, under the condition that the fuel and oxidant ratio is determined, the combustion process is controlled by arranging the heating surface to reduce the furnace temperature. Due to the difference of the fuel, the design of the heating surface is also different, the prior art adopts the scheme of two independent furnaces to solve the above problems, two independent furnaces are coal-fired furnace and waste residue incinerator furnace, two furnaces are arranged with heating surface and are connected at the upper part, the main shortcomings are: first, the waste residue incinerator furnace only discloses the technical features of "waste residue incinerator furnace is arranged with waste residue feeding port, waste residue discharging port and incinerator air supply chamber, waste residue incinerator furnace adopts two-stage combustion design, the first stage combustion adopts turbulent pyrolysis incineration, the combustion temperature is 800-900℃, the second stage combustion is cyclone type mixing chamber combustion, which makes the unburned gas burn out and reaches the high temperature combustion of 900-1000℃", since turbulent flow and cyclone flow are undoubtedly two kinds of gas flow modes, how does the waste residue incinerator furnace arranged with waste residue feeding port, waste residue discharging port and incinerator air supply chamber realize the two kinds of gas flow modes? Second, since the coal-fired furnace and the waste residue incinerator furnace are connected at the upper part, since the volatile matter, moisture and fixed carbon components of the waste residue change greatly, the volatile matter can be regarded as a gas fuel, and the fixed carbon can be regarded as a solid fuel, if the waste residue incinerator furnace has a high volatile matter concentration and a low excess air ratio, the heat of the volatile matter gas combustion is insufficient to make up for the heat loss of the heating surface, so that the fresh combustible gas cannot reach the ignition point and causes extinguishment, the high temperature flue gas of the coal-fired furnace ignites the premixed gas of the combustible gas and air in the waste residue incinerator furnace from the upper part of the waste residue incinerator furnace, which causes backfire, and the premixed gas of the combustible gas and air reaches the explosion mixture concentration limit, which may cause explosion accident; Third, the coal-fired furnace and the waste residue incinerator furnace are connected at the upper part and share a flue gas discharge channel, the pressures of the high temperature flue gas generated by the two furnaces are definitely different, assuming that the positive pressure generated by the coal-fired furnace is higher, the airflow in the waste residue incinerator furnace cannot flow and "hold up", that is, the incinerator air supply chamber cannot deliver air to the furnace, and the flame in the incinerator will be extinguished, and similarly, if the flue gas pressure of the waste residue incinerator furnace is higher than that of the coal-fired furnace, it will also cause the flame in the coal-fired furnace to be extinguished.

[0004] The prior art two "high-efficiency furaldehyde waste residue boiler" is to complete the combustion of furaldehyde waste residue boiler by technical transformation of hand-fired furnace, but the fixed grate, residue discharge port, air supply structure, heating surface, boiler drum, boiler component, flue structure cannot be changed, although the combustion mode is partially changed to layer combustion and suspension combustion by increasing pre-drying and secondary air supply, the adaptability to waste residue combustion is improved, the problem of "frequent opening of furnace door during filling" is solved, that is, frequent adjustment of excess air coefficient, so that the stability of combustion is improved. The prior art two boiler is a double drum transverse type with fixed grate structure, which is improved on the basis of the existing furaldehyde waste residue boiler, and the structure is improved on the basis of the hand-fired furnace structure. The furnace volume heat load has been determined, the residence time of fuel particles in the furnace is insufficient, the fixed carbon particles of the fuel particles, that is, the volatile loss of the waste residue, are incompletely combusted in the furnace and fall and accumulate on the fixed grate. The fuel particles on the fixed grate are quickly extinguished because the air supply is room temperature air and does not reach the ignition temperature (high-temperature flue gas is discharged after heat exchange by water cooling wall and convection tube bundle to directly dry the waste residue, and an air preheater is not designed), and cannot continue to burn on the fixed grate. If the residue accumulates too much, it needs to be cleaned manually, otherwise the air inlet will be blocked.

[0005] The prior art three "impact type airflow pulverizer and powder pulverizing method" is to efficiently produce toner or colored resin powder for toner used in image forming method in electrostatic copying technology. An impact type airflow pulverizer uses jet airflow to convey powder raw materials, so that the powder raw materials collide with the impact part and are pulverized by the impact force. The airflow jet increases the secondary air inlet to balance the resin powder concentration, so as to avoid the resin powder from being too high to be adhered to the surface of the impact plate after colliding with the impact plate. However, it is not suitable for preparing high-activity, superfine and spherical mineral admixtures required by quick-hardening and high-strength Portland cement, because there is moisture in the air, which reacts with the mineral admixtures to harden into cement stone. SUMMARY

[0006] In view of the shortcomings of the prior art, the purpose of the present application is to provide a seaweed waste residue resource recycling method, characterized by: step one, cement clinker is a collection of multiple minerals, and these minerals are composed of four main oxides CaO, SO2, Al2O3 and Fe2O3. The main measures to produce quick-hardening and high-strength Portland cement are: increasing the C3S content and selecting the best parameters, superfine grinding and maximizing the control of particle size distribution, improving the particle morphology, and mineral doping to obtain high activity. Quick-hardening and high-strength cement concrete generally uses No. 525 or higher grade Portland cement and ordinary Portland cement, and at the same time requires the cement to have a high C3S content and fineness (specific surface area 3500-4000 cm 3The characteristics of the clinker, so in the production control, not only to control the content of each oxide in the clinker, but also to control the ratio between the oxide, i.e. the rate value to obtain a higher C3S content; improve the morphology of cement particles is also a method to improve the strength of the cement stone itself, using spheroidization of cement is an important means to achieve high fluidity, high strength and high durability of the concrete, spheroidization of cement is 3-40 μm particles, the particle size distribution range is narrow, the hydration heat release rate peak and total heat is low, the water demand of hydration is small, the water-cement ratio of the preparation of concrete is low, the strength is higher, the spheroidal particle morphology of cement is obtained by high-speed airflow crushing. The circulating fluidized bed boiler can also be considered as a kind of airflow crushing device, the seaweed waste residue is put into the circulating fluidized bed boiler for combustion to recover heat energy, the combustion process is crushed by airflow to recover silica ash slag, and further high-speed airflow crushing can prepare high-activity, superfine, spherical mineral admixture required for fast-hardening and high-strength portland cement. The designed circulating fluidized bed boiler for burning seaweed waste residue includes a main circulation loop and a tail flue, the main circulation loop includes a furnace, a gas-solid separator, and a solid particle return device, the solid particles are carried by airflow in the main circulation loop to complete the first-stage low-speed airflow crushing and classification, the solid particle return device is designed with a high-speed airflow crusher and a differential classifier, and the solid particles are crushed and classified by the high-speed airflow in the second stage; the high-temperature flue gas waste heat discharged from the gas-solid separator is absorbed by the convection evaporation heating surface, i.e. the superheater, the economizer, and the air preheater in the tail flue, the structure of the convection evaporation heating surface generally adopts the structure of upper and lower steam drums, the tube cluster heating surface is expanded and connected between the upper and lower steam drums, and the steam-water mixture generated by the convection evaporation heating surface is sent into the drum for steam-water separation.

[0007] Step two, primary combustion air passes through the air chamber at the bottom of the furnace, through the water-cooled air distribution plate into the furnace, and secondary air enters the furnace at the furnace converging section. The fuel burns and releases heat in the furnace, and the generated heat is cooled and absorbed by the water-cooled walls around the furnace and the convection evaporation heating surface at the top of the furnace. The remaining part is absorbed by the convection evaporation heating surface arranged at the tail part. The main fuel is biomass particles, and the auxiliary fuel is seaweed waste residue particles. The converging section divides the furnace into two parts, the upper part is the dilute phase zone, and the lower part is the dense phase zone. The seaweed waste residue particles are composed of combustible insoluble fibers and perlite inert materials, which are sent to the dense phase zone by a screw conveyor. The perlite inert material acts as a bed material to provide a stable high-temperature hot storage layer for the furnace, which is a stable ignition source. The volatile matter in the newly added fuel and the unburned coke sent back by the solid particle return device are fluidized and combusted by the primary air flow. The purpose of designing the furnace converging section is also to increase the probability of mechanical friction between the coarse perlite particles and the furnace wall. The high-temperature hot storage layer will also cause the thermal stress caused by the temperature difference between the inside and outside of the waste residue particles during the heating process, the pressure when the volatile matter is precipitated, and the rupture of the C-C, C-H, and C-O bonds that form crystals, which will cause the particles to break rapidly. The fine particles formed by the above abrasion and crushing are carried out of the furnace by the fluidized gas flow, providing conditions for the preparation of high-activity, ultra-fine, and spherical perlite admixture. Biomass particles are input into the dilute phase zone, which is an oxygen-rich combustion area. The coke particles in the fuel are burned out in this area. By adjusting the flow ratio of primary air and secondary air according to the change of boiler load, biomass fuel and seaweed waste residue fuel can be burned in the dilute phase zone and the dense phase zone, and heat exchange and mass exchange can be completed.

[0008] Step three, the gas-solid separator is built by firebrick into two settling chambers, the coarse particles in the flue dust collide and separate to fall through the airlock valve I, the material pipe I inputs the solid particle return device, the fine particles in the flue dust are transported to the bag-type dust collector for environmental protection treatment through the tail flue, the fine particles after gas-solid separation fall through the airlock valve II, the material pipe II also inputs the solid particle return device, the solid particle return device is composed of a high-speed airflow pulverizer and a differential classifier, the high-speed airflow pulverizer includes a cyclone classifier, a steam ejector I and a steam ejector II, the steam ejector I and the steam ejector II are both designed with a Laval nozzle, a mixing chamber and a diffuser chamber, the working steam is accelerated through the Laval nozzle, reaches the sound speed at the nozzle throat, and the airflow continues to accelerate in the nozzle expansion section, and the supersonic airflow obtained at the outlet is injected into the mixing chamber. In this process, the pressure energy of the high-pressure working steam is converted into function, the outlet pressure drops to cause negative pressure in the mixing chamber, and the above-mentioned particles are sucked in, the working steam and the sucked particles flow in the mixing chamber, the working steam and the sucked particles exchange momentum and energy in the mixing chamber, so that the velocities of the two gradually tend to be consistent, the mixed airflow is decelerated and pressurized in the diffuser chamber, a positive shock wave appears at the throat thereof, the pressure of the airflow suddenly rises, and the velocity suddenly drops to subsonic speed, the velocity is further reduced and the pressure is further increased in the expansion section thereof, so that the kinetic energy is converted into pressure energy, finally the mixed airflow with the high-temperature and high-pressure working steam is ejected out of the diffuser chamber, the steam ejector I and the steam ejector II are opposite to each other, the high-speed jet airflow respectively carries the coarse and fine particles in the flue dust along the tangent direction of the cyclone drum, forms a circular flow between the cyclone drum and the center drum, and spirally moves downward, the residence time of the particles is prolonged, the particles collide intensively, the particle size is reduced, the surface is smooth and the activity is high due to the friction with the drum wall, the airflow moves downward to the ash hopper, and due to the blockage of the airlock valve III, the airflow flows upward, the particles are classified due to the airflow elutriation and entrainment, the coarse particles are sent back to the furnace through the airlock valve III, and the fine particles enter the differential classifier from the center drum along with the airflow.

[0009] Step four, differential classifier includes airlock valve IV, lower body assembly, upper body assembly, impeller rotor, the working principle of differential classifier is to utilize high-speed airflow conveying branch pipeline flow distribution characteristics: closed pipeline branch flow is proportional to pneumatic energy, change the airflow flow entering the impeller rotor, cooperate with the centrifugal force flow field and friction force flow field formed by different speed impeller rotor, form variable friction force, centrifugal force to particle, so as to realize cutting classification according to particle size requirement. Lower body assembly includes outer cone hopper, inner cone hopper, inner inclined pipe, upper body assembly includes finished product pipe, classification chamber, guide vane, airflow flows upward through the passage formed by outer cone hopper and inner cone hopper, is uniformly distributed and is tangent to guide vane and is introduced into classification chamber, airflow is divided into two branches in classification chamber, main branch is that airflow passes through the blade of impeller rotor and enters inner cavity and is transported to finished product collecting bin through finished product pipe; Auxiliary branch is that it is sent back to furnace through inner cone hopper, inner inclined pipe and airlock valve IV, the airflow flow of two branches can be distributed by adjusting the motor speed of airlock valve IV, so as to adjust the pneumatic energy of main branch, the blade is designed as equal section straight blade, the guide vane is static blade, the blade of impeller rotor is dynamic blade, the differential speed of the two and the structure of inlet and outlet flow channel form variable friction force, centrifugal force to particle, the more adjustable technical means, the narrower particle size distribution range and the finer particle size obtained by classification.

[0010] Compared with the prior art, the present application has at least the following advantages: first, the seaweed waste residue is put into the circulating fluidized bed boiler for combustion to recover heat energy, and the combustion process is pulverized by airflow to recover silica ash residue, and further high-speed airflow pulverization can prepare high-activity, superfine and spherical mineral admixture required for quick-hardening and high-strength portland cement; second, the circulating fluidized bed boiler for burning seaweed waste residue includes a main circulation loop and a tail flue, the main circulation loop includes a furnace, a gas-solid separator and a solid particle returning device, the solid particles are subjected to first-stage low-speed airflow pulverization and classification in the main circulation loop under the entrainment of airflow, the solid particle returning device is designed with a high-speed airflow pulverizer and a differential classifier, and the solid particles are subjected to second-stage high-speed airflow pulverization and classification, and the high-activity, superfine and spherical mineral admixture with narrow particle size distribution range can be obtained through two-stage airflow pulverization and classification. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a front view structural schematic diagram of the seaweed waste residue resource recycling method of the present application.

[0012] Figure 2 It is a front view structural schematic diagram of the seaweed waste residue resource recycling method of the present application.

[0013] Figure 3 It is a front view structural schematic diagram of the seaweed waste residue resource recycling method of the present application.

[0014] Figure 4C sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0015] Figure 5 D sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0016] Figure 6 E sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0017] Figure 7 F sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0018] Figure 8 G sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0019] Figure 9 H-H section structure schematic diagram of the seaweed waste residue resource recycling method.

[0020] Figure 10 I-I section structure schematic diagram of the seaweed waste residue resource recycling method.

[0021] Figure 11 J sample structure schematic diagram of the seaweed waste residue resource recycling method.

[0022] 1 - main circulation loop 2 - tail flue 3 - furnace 4 - gas-solid separator 5 - solid particle return device 6 - drum 7 - superheater 8 - economizer 9 - air preheater 10 - air chamber 11 - water-cooled air distribution plate 12 - secondary air pipe 13 - air lock valve I 14 - material pipe I 15 - steam ejector I 16 - bag-type dust collector 17 - air lock valve II 18 - material pipe II 19 - high-speed airflow pulverizer 20 - steam ejector II 21 - differential classifier 22 - cyclone classifier 23 - Laval nozzle 24 - mixing chamber 25 - diffuser chamber 26 - center cylinder 27 - cyclone cylinder 28 - ash bucket 29 - air lock valve III 30 - air lock valve IV 31 - lower body assembly 32 - upper body assembly 33 - impeller rotor 34 - outer cone bucket 35 - inner cone bucket 36 - inner inclined pipe 37 - finished product pipe 38 - classification chamber 39 - guide grid 40 - blade. DETAILED DESCRIPTION

[0023] The application will be further described in connection with the drawings and specific embodiments.

[0024] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 A seaweed waste residue resource recycling method is shown, characterized by: step one, cement clinker is a collection of multiple minerals, and these minerals are combined by four main oxides CaO, SO2, Al2O3 and Fe2O3, the main measures for producing fast-hard and high-strength Portland cement are: increasing C3S content and selecting the best parameters, superfine grinding and maximum control of particle size distribution, improving particle morphology, and mineral doping to obtain high activity. Fast-hard and high-strength cement concrete generally uses Portland cement with a 525 or higher grade or ordinary Portland cement, and at the same time requires the cement to have a higher C3S content and fineness (specific surface area 3500-4000 cm 3The characteristics of the clinker, so in the production control, not only to control the content of each oxide in the clinker, but also to control the ratio between the oxide, namely the rate value to obtain a higher C3S content; improve the morphology of cement particles is also a method to improve the strength of cement itself, using spheroidization of cement is an important means to achieve high fluidity, high strength and high durability of the coagulation, spheroidization of cement is 3-40 μm particles, the particle size distribution range is narrow, the hydration heat release rate peak and the total heat is low, the water demand of hydration is small, the water-cement ratio of the preparation of concrete is low, the strength is higher, the spheroidization of the particle morphology of cement is obtained by high-speed airflow crushing. The circulating fluidized bed boiler can also be considered as a kind of airflow crushing device, the seaweed waste residue is put into the circulating fluidized bed boiler for combustion to recover heat energy, the combustion process is crushed by airflow to recover silica ash slag, and further high-speed airflow crushing can prepare high-activity, superfine, spherical mineral admixture required for fast-hardening and high-strength portland cement. The circulating fluidized bed boiler designed for burning seaweed waste residue includes a main circulation loop 1 and a tail flue 2, the main circulation loop 1 includes a furnace 3, a gas-solid separator 4, and a solid particle return device 5, the solid particles are subjected to first-stage low-speed airflow crushing and grading in the main circulation loop 1 under the entrainment of airflow, the solid particle return device 5 is designed with a high-speed airflow crusher 19 and a differential classifier 21, and the solid particles are subjected to second-stage high-speed airflow crushing and grading in the solid particle return device 5; the high-temperature flue gas waste heat discharged from the gas-solid separator 4 is absorbed by the convection evaporation heating surface, i.e., the superheater 7, the economizer 8, and the air preheater 9 in the tail flue 2, the structure of the convection evaporation heating surface generally adopts an upper and lower double drum structure, the tube cluster heating surface is expanded and connected between the upper and lower drums, and the steam-water mixture generated by the convection evaporation heating surface is sent to the drum 6 for steam-water separation.

[0025] Step two, primary combustion air enters the furnace 3 through the air chamber 10 at the bottom of the furnace 3, the water-cooled cloth air plate 11, the secondary air enters the furnace 3 at the convergence part of the furnace 3, the fuel burns and releases heat in the furnace 3, the generated heat is cooled and absorbed by the water-cooled wall around the furnace 3 and the convection evaporation heating surface arranged at the top of the furnace 3, the rest is absorbed by the convection evaporation heating surface arranged at the tail part, the main fuel is biomass particles, and the auxiliary fuel is seaweed waste residue particles, the convergence part divides the furnace 3 into upper and lower parts, which are divided according to the solid fluidized state, the upper part is the dilute phase zone, and the lower part is the dense phase zone, the seaweed waste residue particles are composed of combustible insoluble fibers and perlite inert materials, which are sent into the dense phase zone by the screw conveyor, the perlite inert material as the bed material provides a stable high-temperature hot storage layer for the furnace 3, which is a stable ignition source, the volatile matter in the newly added fuel and the unburned coke sent back by the solid particle return device 5 are combusted here by the primary air flow, the purpose of designing the convergence part of the furnace 3 is also to increase the probability of mechanical friction between the coarse perlite particles and the furnace wall, the high-temperature hot storage layer will also cause the rapid rupture of the particles caused by the thermal stress of the waste residue particles during the heating process, the pressure when the volatile matter is precipitated, and the rupture and decomposition of the C-C, C-H, and C-O bonds that constitute the crystal, the above abrasion and crushing form fine particles that are carried out of the furnace by the fluidized gas flow, which provides conditions for preparing high-activity, ultra-fine, and spherical perlite admixture; the biomass particle fuel is input into the dilute phase zone, which is an oxygen-enriched combustion area, the coke particles in the fuel are burned out in this area, the flow ratio of the primary air and the secondary air can be adjusted according to the change of the boiler load, so that the biomass fuel and the seaweed waste residue fuel can be burned in the dilute phase zone and the dense phase zone and complete heat exchange and mass exchange.

[0026] Step three, the gas-solid separator 4 is built by refractory bricks into two settling chambers, the coarse particles in the flue dust collide and separate to fall through the airlock valve I 13, the material pipe I 14 inputs the solid particle return device 5, the fine particles in the flue dust are transported to the bag dust collector for environmental protection treatment through the tail flue 2, the fine particles after gas-solid separation fall through the airlock valve II 17, the material pipe II 18 also input the solid particle return device 5, the solid particle return device 5 is composed of a high-speed airflow pulverizer 19 and a differential classifier 21, the high-speed airflow pulverizer 19 includes a cyclone classifier 22, a steam ejector I 15 and a steam ejector II 20, the steam ejector I 15 and the steam ejector II 20 are both designed with a Laval nozzle 23, a mixing chamber 24 and a diffuser chamber 25, the working steam is accelerated through the Laval nozzle 23, reaches the speed of sound at the nozzle throat, and the airflow continues to accelerate in the nozzle expansion section, and the supersonic airflow obtained at the outlet is injected into the mixing chamber 24. In this process, the pressure energy of the high-pressure working steam is converted into function, and the outlet pressure drops to cause the negative pressure of the mixing chamber 24, which sucks the above-mentioned particles, the working steam and the sucked particles flow in the mixing chamber 24, the working steam and the sucked particles exchange momentum and energy in the mixing chamber 24, so that the velocities of the two gradually tend to be consistent, the mixed gas flow is decelerated and pressurized in the diffuser chamber 25, a positive shock wave appears at the throat thereof, the pressure of the gas flow suddenly rises, and the velocity suddenly drops to subsonic speed, and in the expansion section thereof, the velocity further decreases and the pressure further rises, realizing the conversion of kinetic energy into pressure energy, finally the mixed gas flow with high-temperature and high-pressure working steam is ejected out of the diffuser chamber 25, the steam ejector I 15 and the steam ejector II 20 are opposite to each other, the high-speed jet flow respectively carries the coarse and fine particles in the flue dust along the tangent direction of the cyclone drum 27, forms a circulating flow between the cyclone drum 27 and the center cylinder 26 and spirally moves downward, the residence time of the particles is prolonged, the particles increase the probability of violent collision, and the particles are small in size, smooth in surface and high in activity due to the friction with the cylinder wall, the particles flow upward due to the blockage of the airlock valve III 29 after the airflow is carried down to the ash hopper 28, the particles are classified due to the airflow elutriation and entrainment, the coarse particles are sent back to the furnace 3 through the airlock valve III 29, and the fine particles enter the differential classifier 21 with the airflow from the center cylinder 26.

[0027] Step four, differential classifier 21 includes dampers IV 30, lower body assembly 31, upper body assembly 32, impeller rotor 33, differential classifier 21 working principle is to use high-speed airflow transport branch pipeline flow distribution characteristics: closed pipeline branch flow and pneumatic energy is proportional to the relationship, change into the impeller rotor 33 airflow flow, with different speed impeller rotor 33 formed by the centrifugal force flow field and friction force flow field, to the particles form variable friction, centrifugal force, so as to realize according to the particle size requirements cutting classification. Lower body assembly 31 includes outer cone hopper 34, inner cone hopper 35, inner inclined pipe 36, upper body assembly 32 includes finished product pipe 37, classification chamber 38, guide grid 39, airflow through the channel formed by the outer cone hopper 34 and inner cone hopper 35 upward flow, through the guide grid 39 uniform shunt and tangent guide into the classification chamber 38, in the classification chamber 38 airflow is divided into two branches, the main branch is the airflow through the blades of impeller rotor 33 into the inner cavity through the finished product pipe 37 to the finished product collection warehouse; auxiliary branch is through the inner cone hopper 35, inner inclined pipe 36 and dampers IV 30 back to the furnace 3, adjust the motor speed of dampers IV 30, can distribute two branch airflow flow, so as to adjust the main branch pneumatic energy, blade design is equal section straight blade, guide grid 39 is a static blade, the blade of impeller rotor 33 is a dynamic blade, the differential of the two and the inlet and outlet flow structure to the particles form variable friction, centrifugal force, the more adjustable technical means, through classification obtained the particle size distribution range is narrower, the finer the particle size.

Claims

1. A method for recycling and utilizing seaweed waste, characterized by: Step one: Cement clinker is a multi-mineral aggregate, composed of four main oxides: CaO, SO2, Al2O3, and Fe2O3. The main measures for producing rapid-hardening, high-strength silicate cement are: increasing C3S content and selecting optimal parameters, ultrafine grinding and maximizing control of particle size distribution, improving particle morphology, and mineral doping to obtain high activity. Rapid-hardening, high-strength cement concrete generally uses silicate cement of grade 525 or higher and ordinary silicate cement, while requiring the cement to have a high C3S content and fineness (specific surface area 3500–4000 cm³). 3 Due to the characteristics of / g), in production control, it is necessary not only to control the content of each oxide in the clinker, but also to control the ratio between each oxide, i.e., the ratio value, to obtain a higher C3S content. Improving the morphology of cement particles is also a way to improve the strength of cement stone itself. The heat energy can be recovered by burning seaweed waste in a circulating fluidized bed boiler. The silica ash can be recovered by being pulverized by airflow during the combustion process. Further high-speed airflow pulverization can prepare the high-activity, ultrafine, spherical mineral admixture required for fast-hardening and high-strength silicate cement. The designed circulating fluidized bed boiler for burning seaweed waste includes a main circulation loop and a tail flue. The main circulation loop includes a furnace, a gas-solid separator, and a solid particle return device. Solid particles undergo first-stage low-speed airflow pulverization and classification in the main circulation loop under the entrainment of the airflow. The solid particle return device is designed with a high-speed airflow pulverizer and a differential classifier, where solid particles undergo second-stage high-speed airflow pulverization and classification. The waste heat from the high-temperature flue gas discharged from the gas-solid separator is absorbed by the convective evaporation heating surfaces in the tail flue, namely the superheater, economizer, and air preheater. The convective evaporation heating surfaces generally adopt an upper and lower double steam drum structure, with the tube bundle heating surface expanded between the upper and lower steam drums. The steam-water mixture generated by the convective evaporation heating surfaces is sent to the boiler drum for steam-water separation. In the second step, primary combustion air enters the furnace through the air chamber at the bottom of the furnace and the water-cooled air distribution plate, while secondary air... The fuel enters the furnace at the converging section, where it burns and releases heat. The heat generated by combustion is cooled and absorbed by the water-cooled walls around the furnace and the convective evaporative heating surface at the top. The remaining heat is absorbed by the convective evaporative heating surface at the tail end. The main fuel is biomass pellets, and the auxiliary fuel is seaweed waste pellets. The seaweed waste pellets are composed of combustible insoluble fibers and perlite inert materials. They are fed into the dense phase zone by a screw conveyor. The volatile matter in the newly added fuel and the unburned coke returned by the solid particle return device are combusted here by the primary air fluidization. The biomass pellet fuel is fed into the dilute phase zone, which is an oxygen-rich combustion zone. The coke particles in the fuel are burned completely in this zone. The ratio of primary air to secondary air flow can be adjusted according to the boiler load changes, so that the biomass fuel and seaweed waste fuel can burn in the dilute and dense phase zones and complete heat and mass exchange.Step 3: The gas-solid separator is constructed of refractory bricks into two settling chambers. Coarse particles in the flue gas collide and separate, falling through airlock valve I and feed pipe I into the solid particle return device. Fine particles in the flue gas are transported through the tail flue to the bag filter for environmental treatment. The fine particles after gas-solid separation also fall through airlock valve II and feed pipe II into the solid particle return device. The solid particle return device consists of a high-speed airflow pulverizer and a differential classifier. The high-speed airflow pulverizer includes a cyclone classifier, steam ejector I, and steam ejector II. Steam ejector I and steam ejector... Both units II are designed with Laval nozzles, mixing chambers, and diffusers. Steam ejectors I and II are positioned opposite each other. High-speed jets carry coarse and fine particles from the flue gas, injecting them tangentially along the cyclone separator. This creates a circulation between the cyclone separator and the central cylinder, causing the particles to spiral downwards. This prolongs the residence time of the particles, increasing the probability of intense collisions. Combined with friction against the cylinder wall, this results in smaller particle sizes, smoother surfaces, and higher activity. After descending to the ash hopper, the airflow is deflected upwards by the shut-off valve III, causing the particles to be lifted and entrained by the airflow. The process achieves classification. Coarser particles are returned to the furnace via the air shut-off valve III, while finer particles are carried by the airflow into the differential classifier through the central cylinder. Step four: The differential classifier includes air shut-off valve IV, a lower body assembly, an upper body assembly, and an impeller rotor. The lower body assembly includes an outer cone hopper, an inner cone hopper, and an inner inclined tube. The upper body assembly includes a finished product pipe, a classification chamber, and a guide grid. The airflow flows upward through the channel formed by the outer and inner cone hoppers, is evenly distributed by the guide grid, and tangentially guided into the classification chamber. Inside the classification chamber, the airflow splits into two branches. The main branch is where the airflow passes through the blades of the impeller rotor. The air enters the inner cavity and is transported to the finished product collection bin via the finished product pipe; the auxiliary branch is returned to the furnace via the inner conical hopper, inner inclined pipe, and air shut-off valve IV. Adjusting the motor speed of air shut-off valve IV can distribute the airflow of the two branches, thereby adjusting the pneumatic energy of the main branch. The blades are designed as straight blades with a uniform cross-section, the guide vanes are stationary blades, and the impeller rotor blades are moving blades. The speed difference between the two and the inlet and outlet flow channel structure create variable friction and centrifugal force on the particles. That is, the more adjustable technical means there are, the narrower the particle size distribution range and the finer the particle size obtained through grading.

2. The method for recycling seaweed waste according to claim 1, characterized in that: The use of spheroidized cement is an important means of achieving high fluidity, high strength, and high durability in concrete. Spheroidized cement consists of particles between 3 and 40 μm in size, with a narrow particle size distribution. It has a low peak hydration heat release rate and low total heat release, resulting in low water demand for hydration. This leads to a low water-cement ratio and high strength in the concrete produced. Spheroidized cement particles are obtained through high-speed airflow pulverization. Circulating fluidized bed boilers can also be considered a type of airflow pulverization device.

3. The method for recycling seaweed waste according to claim 1, characterized in that: The converging section divides the furnace into upper and lower parts, distinguished by the solid fluidization state: the upper part is the dilute phase region, and the lower part is the dense phase region.

4. The method for recycling seaweed waste according to claim 1, characterized in that: Perlite inert material, as a bed material, provides a stable high-temperature incandescent heat storage layer in the furnace and serves as a stable ignition source.

5. The method for recycling seaweed waste according to claim 1, characterized in that: The purpose of designing the furnace constriction section is also to increase the probability of coarse perlite particles colliding with each other and mechanical friction with the furnace wall. The high-temperature hot regenerator layer will also cause the waste residue particles to break rapidly due to thermal stress caused by the temperature difference between the inside and outside during the heating process, or the pressure when volatiles are released, or the breaking and decomposition of the CC, CH, CO bonds that make up the crystals. The fine particles formed by the above abrasion and crushing effects are carried out of the furnace by the fluidized airflow, providing conditions for the preparation of highly active, ultrafine, spherical perlite admixtures.

6. The method for recycling seaweed waste according to claim 1, characterized in that: The working steam is accelerated through the Laval nozzle, reaching the speed of sound at the nozzle throat. The airflow continues to accelerate in the nozzle expansion section, and the supersonic airflow obtained at the outlet is injected into the mixing chamber. During this process, the pressure energy of the high-pressure working steam is converted into energy, and its outlet pressure drops, creating a negative pressure in the mixing chamber, which draws in the aforementioned particulate matter.

7. The method for recycling seaweed waste according to claim 1, characterized in that: The working steam and the inhaled particles flow in the mixing chamber, where they exchange momentum and energy, causing their velocities to gradually become equal. The mixed airflow decelerates and increases pressure in the diffuser, where a normal shock wave appears at its throat, causing the airflow pressure to rise sharply and its velocity to drop to subsonic speed. In its expansion section, the velocity further decreases and the pressure further increases, realizing the conversion of kinetic energy into pressure energy. Finally, the mixed airflow, carrying the high-temperature and high-pressure working steam, is ejected at high speed through the diffuser.

8. The method for recycling seaweed waste according to claim 1, characterized in that: The working principle of the differential classifier is to utilize the flow distribution characteristics of the high-speed airflow conveying branch pipeline: the flow rate of the closed pipeline branch is proportional to the pneumatic energy. By changing the flow rate of the airflow entering the impeller rotor, and in conjunction with the centrifugal force flow field and frictional force flow field formed by the impeller rotors with different speeds, the variable frictional force and centrifugal force are formed on the particles, thereby achieving cutting and classification according to the particle size requirements.

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