Preparation process of seaweed charcoal ground powder and carbon-based master batch forming method thereof

Abstract

The application discloses a preparation process of seaweed carbon grinding powder and a carbon-based master batch forming method, relates to the technical field of biochar preparation, and is characterized in that seaweed raw materials are arranged into sheet or granular shape, desalted liquid is sprayed from the outer surface and the spraying is stopped before the desalted liquid reaches the central area, and hot seaweed carbon is obtained through solid-liquid separation, drying, low-temperature devolatilization and high-temperature carbonization; after the pyrolysis gas of the same batch of seaweed is dedusted and the high-temperature condensate components obtained through segmented condensation are shunted, the high-temperature condensate components are introduced into the seaweed carbon surface deposition area and the inert atmosphere crushing area respectively, so that the high-temperature condensate components are deposited on the outer surface and the fresh crushing section and are carbonized through heat preservation, and seaweed carbon grinding powder is obtained through cooling and grading; the powder is side-fed into the polymer melt which has been plasticized, and the carbon-based master batch is prepared through pre-wetting, dispersion mixing, homogenization, vacuum exhaust, extrusion and pelletizing; the application is favorable for reducing the hygroscopicity, oil absorption value and migration ion level of the powder, effectively improving the side-feeding stability and melt dispersity, and reducing the agglomeration and the increase of filtration pressure.

Description

Technical Field

[0001] This invention relates to the field of biochar preparation technology, and in particular to a preparation process for seaweed charcoal powder and a method for forming carbon-based masterbatch. Background Technology

[0002] Seaweed biomass contains polysaccharides, proteins, and mineral components such as calcium, magnesium, silicon, and phosphorus. Seaweed char powder can be obtained through desalination, pyrolysis carbonization, pulverization, and grading. Among them, seaweed char powder refers to the fine seaweed char powder obtained by pyrolysis carbonization of seaweed raw materials, followed by pulverization, heat preservation carbonization, and particle size classification under hot or controlled atmosphere. It is used as a functional filler in polymer composites and carbon-based masterbatches. Existing technologies usually use overall soaking or repeated water washing to reduce the soluble salt content, physical or chemical activation to increase the specific surface area and pore volume, or use coupling agents, compatibilizers, and resin coating to improve the interfacial compatibility between char powder and polymer melt.

[0003] However, in existing technical approaches, prolonged overall immersion or repeated washing can lead to the migration of some seaweed-derived mineral components while reducing soluble salts. Strong activation and pore-enhancing treatments can increase the proportion of open pores, oil absorption value, and moisture absorption tendency. If surface modification mainly occurs on the outer surface of the particles before pulverization, the fresh cross-section produced by pulverization will still expose more polar functional groups or interconnected channels. Therefore, when some seaweed carbon powder is used for the molding of highly filled carbon-based masterbatches, processing stability problems such as side-feeding fluctuations, insufficient melt wetting, particle agglomeration, or increased filtration pressure may still occur. Summary of the Invention

[0004] In a first aspect, the present invention provides a process for preparing seaweed charcoal powder, comprising the following steps: The seaweed raw material is sorted into any form, such as sheet or granule. Desalination solution is sprayed from the outer surface of the seaweed raw material. The spraying is stopped before the desalination solution reaches the central area of ​​the seaweed raw material. After solid-liquid separation and drying, seaweed carbonization precursor is obtained. The seaweed carbonization precursor is fed into a pyrolysis device, where it undergoes low-temperature devolatilization and high-temperature carbonization in an inert atmosphere to produce hot seaweed char. The pyrolysis gas generated by the pyrolysis is then subjected to dust removal and segmented condensation to collect the high-temperature condensed components. The high-temperature condensed components are processed into either a gasified or atomized state and then returned to the hot seaweed char surface deposition area. After surface deposition and heat preservation carbonization, a carbonized deposition layer is formed on the outer surface of the seaweed char. The seaweed charcoal of the carbonized deposit layer is fed into a pulverizing device under an inert atmosphere in a hot state, and the high-temperature condensed components are processed into either a gasified state or an atomized state before being introduced into the pulverizing zone, where they come into contact with the fresh cross-section of the seaweed charcoal during the pulverizing process. The pulverized seaweed charcoal is fed into a heat-insulating carbonization zone, where it is cooled and classified by particle size to obtain seaweed charcoal powder.

[0005] Preferably, the seaweed raw material is processed into any form, either sheet material with a thickness of 2-6 mm or granular material with a particle size of 2-6 mm, and the contact time between the desalination solution and the seaweed raw material is 20-90 s.

[0006] Preferably, the low-temperature devolatilization temperature is 280–360°C, and the high-temperature carbonization temperature is 540–620°C.

[0007] Preferably, the high-temperature condensing component is taken from the high-temperature condensing section of the segmented condensation process, the wall temperature of the high-temperature condensing section is 150-220°C, and the amount of the high-temperature condensing component returned to the seaweed carbon surface deposition area and the crushing area is 3%-8% based on the dry weight of the seaweed carbon after high-temperature carbonization.

[0008] Preferably, the temperature of the seaweed charcoal that forms the carbonized deposit layer when it enters the pulverizing device is 180–300°C.

[0009] Preferably, the high-temperature condensed components are split into a first stream and a second stream. The first stream is introduced into the surface deposition zone of the hot seaweed charcoal, and the second stream is introduced into the pulverizing zone. The pulverized seaweed charcoal is then sent to the heat-insulating carbonization zone connected to the end of the carbonization section.

[0010] Secondly, the present invention provides a method for forming carbon-based masterbatch, comprising the following steps: Seaweed charcoal powder is obtained by surface desalination treatment of seaweed raw materials, inert atmosphere pyrolysis treatment, high temperature condensation component return deposition treatment, hot crushing treatment and cross-sectional carbonization treatment, and the high temperature condensation component comes from the pyrolysis gas of the same batch of seaweed raw materials. The polymer carrier resin is added to the barrel of the twin-screw extruder through the main feed port, forming a continuous polymer melt in the main plasticizing section; The seaweed charcoal powder is fed into a continuous polymer melt through a side feed port located downstream of the main plasticizing section, and passes through a pre-wetting section, a dispersion and mixing section and a homogenization section in sequence. The homogenized molten mixture is vacuum degassing, extruded through a die head, cooled, and pelletized to obtain carbon-based masterbatch.

[0011] Preferably, the seaweed charcoal powder is dried, sieved, and metered before being added to the cylinder in powder form through the side feed port.

[0012] Preferably, the polymer carrier resin is selected from either polypropylene or polylactic acid.

[0013] Preferably, the pre-wetting section is equipped with a conveying thread element and a low-shear mixing element, the dispersing and mixing section is equipped with a kneading element, the homogenizing section is equipped with a conveying thread element, and the vacuum exhaust port is located in the downstream barrel section of the homogenizing section.

[0014] The beneficial effects of this invention are: By using surface-deep desalination, homologous high-temperature condensation component diversion deposition, and hot-state pulverization cross-section passivation, seaweed charcoal grinding can achieve a radial gradient structure with relatively low salt, low polarity, and low porosity in the outer layer, while retaining seaweed mineral components in the core. This helps reduce the powder's moisture absorption rate, oil absorption value, and level of migratable ions, reduces the active exposure of the fresh cross-section after pulverization, and improves the powder's wetting, dispersion, and side-feeding stability in polymer melts. This, in turn, helps reduce agglomeration and filtration pressure, and improves the stability of continuous molding of carbon-based masterbatches. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the seaweed charcoal grinding process in Example 1; Figure 2 This is a flowchart of the carbon-based masterbatch molding method in Example 1. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] The seaweed raw material of this invention is selected from seaweed biomass that has been naturally dried or dried at low temperature. The seaweed biomass includes at least one of kelp, Sargassum, Undaria pinnatifida, and Ulva prolifera. Before use, remove sand, shell fragments and other foreign impurities from the seaweed raw material. Then, quickly rinse the surface with clean water to remove any adhering substances. After draining, cut, crush or screen the seaweed raw material to make it into sheet or granular material. The thickness of flaky materials is measured by the distance between the outer surfaces on both sides in the thickness direction, and the particle size of granular materials is measured by the sieve particle size.

[0019] The surface-deep desalination refers to making the desalination liquid mainly contact the outer surface of the seaweed raw material and the surface area near the outer surface, and ending the spraying or rinsing before the desalination liquid enters the central area of ​​the seaweed raw material. For sheet-like materials, the central region is defined as the middle third of the thickness direction; for granular materials, the central region is defined as the area near the geometric center of the particle and at a depth greater than half the equivalent radius of the particle from the outer surface. After surface-level desalination, the seaweed material can be cut along the thickness or particle size direction, and samples from the outer layer and the central area can be taken respectively. The water immersion conductivity, chloride ion content, sodium ion content or potassium ion content can be used as the basis for judging the depth of desalination. When the water leaching conductivity, chloride ion content, sodium ion content, or potassium ion content of the outer layer sample is lower than that of the central area sample, and the central area sample still contains detectable calcium, magnesium, silicon, and phosphorus mineral elements from seaweed, it is determined that a seaweed carbonization precursor with low surface migration salt and retained mineral components in the inner layer has been formed.

[0020] The desalination solution is deionized water, low conductivity water, weakly acidic aqueous solution, or aqueous solution containing a small amount of organic acid; the desalination solution is applied to the outer surface of the seaweed raw material by spraying, rinsing, or atomizing spraying. The low conductivity water has a conductivity of no more than 10 μS / cm at 25°C; the weakly acidic aqueous solution has a pH of 4.0 to 6.5; the aqueous solution containing a small amount of organic acid has an organic acid mass fraction of 0.01% to 0.30%, and the organic acid includes citric acid, acetic acid, or lactic acid; After desalination, solid-liquid separation is carried out by draining through a filter screen, centrifugation, or pressure filtration, followed by hot air drying, vacuum drying, or inert atmosphere drying to obtain the seaweed carbonization precursor.

[0021] The seaweed carbonization precursor is fed into a pyrolysis device for pyrolysis treatment; the pyrolysis device is a tube furnace, rotary furnace, moving bed pyrolysis furnace or an inert atmosphere pyrolysis furnace with a continuous feeding and discharging structure. Before pyrolysis, nitrogen or argon is introduced into the pyrolysis device to replace the air, so that the pyrolysis space is in an inert atmosphere. The pyrolysis process includes a low-temperature devolatilization stage and a high-temperature carbonization stage. The low-temperature devolatilization stage is used to remove moisture and low-boiling-point volatile components, while the high-temperature carbonization stage is used to form the seaweed carbon skeleton and retain the core mineral components. The hot seaweed carbon obtained from pyrolysis is transferred to the surface deposition zone under an inert atmosphere.

[0022] The pyrolysis gas generated during the pyrolysis process is filtered by cyclone dust removal, metal mesh dust removal or high temperature resistant filter before entering the segmented condensation device; the segmented condensation device includes a high temperature condensation section and a low temperature condensation section, the high temperature condensation section is used to collect homologous high temperature condensation components with higher boiling points. The homologous high-temperature condensing component originates from the pyrolysis gas of the same batch of seaweed raw materials. After being heated and vaporized, carried out by carrier gas or atomized by nozzle, the homologous high-temperature condensing component forms a gasified or atomized material and is sent back to the surface deposition zone or pulverization zone of the hot seaweed carbon.

[0023] In the surface deposition zone, the homologous high-temperature condensed components in the gaseous or atomized state come into contact with the outer surface of the hot seaweed carbon and are deposited on the outer surface of the seaweed carbon; the deposited seaweed carbon continues to be kept warm and carbonized in an inert atmosphere, so that the deposited components are transformed into a carbonized deposition layer. This carbonized deposited layer forms part of the outer shell of the seaweed carbon particles, causing the outer shell to exhibit a lower migratory salt content, a lower proportion of open pores, and a lower surface oxygen polarity relative to the core.

[0024] The hot seaweed char after the carbonized deposit layer is formed is fed into a pulverizing device; the pulverizing device is an impact mill, air jet mill, shear mill, ball mill or a combination pulverizing device protected by an inert atmosphere; During the pulverization process, the pulverization zone is kept under nitrogen or argon protection, and the gasified or atomized homologous high-temperature condensed components are introduced into the pulverization zone so that the fresh cross-section of the seaweed char produced during the pulverization process comes into immediate contact with the homologous high-temperature condensed components. The pulverized seaweed char is then fed into the heat-insulating carbonization zone, where the homologous components deposited at the cross-section are further carbonized, thereby forming a passivation layer on the newly exposed cross-section. After cooling in an inert atmosphere and particle size classification, seaweed char calcined powder is obtained.

[0025] In this invention, the radial gradient shell-core structure refers to the composition and pore structure characteristics of seaweed charcoal powder particles that change continuously or stepwise from the outside to the inside. Its outer shell has low migratable salt, low open pore ratio and low surface oxygen polarity, while the core retains seaweed-derived mineral components and has a hierarchical porous structure; The radial gradient shell-core structure was confirmed by one or more of the following methods: scanning electron microscopy combined with line or area scanning energy dispersive spectroscopy, X-ray photoelectron spectroscopy surface analysis, Raman spectroscopy, specific surface area and pore size analysis, water extraction conductivity, ion chromatography, and inductively coupled plasma atomic emission spectroscopy.

[0026] Differences in the migratable salts between the outer shell and the inner core are determined by stratified sampling followed by water extraction and detection of conductivity, chloride ions, sodium ions, or potassium ions; the retention of seaweed-derived mineral components is determined by the content of calcium, magnesium, silicon, and phosphorus. Surface oxygen polarity is characterized by the O / C atomic ratio or the proportion of oxygen-containing functional groups measured by X-ray photoelectron spectroscopy. The proportion of open pores was indirectly characterized by nitrogen adsorption, mercury infiltration, liquid adsorption, or oil absorption value. Cross-sectional self-passivation was determined by comparing the O / C atomic ratio, moisture absorption rate, oil absorption value, and water extraction conductivity of the powder cross-section before and after hot sintering.

[0027] The moisture absorption properties of seaweed charcoal powder were characterized by the mass gain rate after constant temperature and humidity. During the test, the sample was dried to constant weight and placed under set temperature and relative humidity conditions for a certain period of time. The moisture absorption rate was calculated based on the mass difference before and after placement. Oil absorption performance is characterized by oil absorption value, with the mass or volume of oily liquid absorbed by a unit mass of seaweed charcoal powder as the evaluation index; salt migration performance is characterized by the conductivity, chloride ion content, sodium ion content or potassium ion content of the water extract. The dispersibility of powder in polymer systems is evaluated by microscopic observation of slices after melt blending, counting of agglomerated particles, filtration pressure rise, or appearance of masterbatch.

[0028] When preparing carbon-based masterbatch using seaweed charcoal grinding powder, the seaweed charcoal grinding powder is first dried, sieved, and metered; then the polymer carrier resin is added to the barrel through the main feed port of the twin-screw extruder to form a continuous polymer melt in the main plasticizing section. Subsequently, the seaweed charcoal powder is added to the continuous polymer melt through the side feed port downstream of the main plasticizing section, and then passes through the pre-wetting section, the dispersion and mixing section, and the homogenization section in sequence. The homogenized molten mixture is then vacuum degassed, extruded through the die head, cooled, and pelletized to obtain carbon-based masterbatch. The processing performance of the masterbatch is evaluated by extrusion torque, melt pressure, filtration pressure rise, masterbatch surface condition, cross-sectional dispersion state, volatile matter, moisture absorption rate, and migration salt content.

[0029] Example 1, referring to Figure 1 and Figure 2 ; Preparation of seaweed charcoal powder and carbon-based masterbatch molding under standard conditions; The same batch of salted kelp stems was selected, batch number KD-2026-01; the kelp stems were rehydrated with deionized water to a wet basis moisture content of 18.0%, and after removing attached sand particles and shell fragments, they were cut into sheet-like materials with a thickness of 4.0, a width of 24, and a length of 38 along the fiber direction. The thickness was measured at three points—the middle and both ends—using a digital caliper, and the average value was taken. The sheet material was then laid in a single layer on a PTFE mesh belt, with the surface density controlled at 4.8 kg / m². 2 .

[0030] Surface-level limited-depth desalination is carried out using a dual-nozzle spray method. The nozzle model is TG-SS-6502, the nozzle diameter is 0.51mm, the distance from the nozzle to the material surface is 180mm, and there is one nozzle at the top and one at the bottom. The spraying pressure is 0.18MPa, the flow rate of a single nozzle is 0.41L / min, the total spraying flow rate is 0.82L / min, the spraying time is 60s, and the desalination liquid dosage is 0.171L / kg wet material. The desalting solution was 25℃ deionized water; to calibrate the process endpoint where the desalting solution did not significantly enter the central area, parallel samples from the same batch were taken and 0.02wt% of brilliant blue tracer was added. After treatment under the same spraying conditions, the outer layer and the central area were cut along the thickness direction. The outer layer is defined as the area within 0.50 mm from each side surface of the sheet, and the central layer is defined as the area 1.33 mm from the center in the thickness direction. Among them, the outer layer and the central layer are the sampling areas for tracer detection and ion extraction detection. The remaining thickness between the two that is not sampled is the transition area and is not included in the statistical sampling range of the outer layer or the central layer. The absorbance of the tracer was measured using a UV-Vis spectrophotometer, and the tracer concentration in the central region was calculated according to the standard curve. When the tracer concentration in the central region is not higher than 5.0% of the initial tracer concentration in the desalination solution, it is recorded as the depth-limited desalination endpoint; in this embodiment, the tracer concentration in the central region is 3.4%. Immediately after spraying, the material is centrifuged at 1800 rpm for 90 seconds to remove liquid. Then, it is dried in a 70℃ hot air circulating oven for 4 hours to reduce the moisture content of the material to below 7.5%, thus obtaining the seaweed carbonization precursor.

[0031] Three samples each from the outer layer and central region of the carbonized precursor were taken for extraction and analysis. 1.000 g of dry sample from each region was weighed, added to 20.0 mL of deionized water, and extracted with shaking at 25°C for 30 min. The conductivity and Na+ of the extract were measured. + K + and Cl - Content; A separate sample was digested with nitric acid-hydrogen peroxide and the contents of Ca, Mg, Si, and P were determined by ICP-OES. outer region Na + Extraction volume and Na content in the central region + The extraction ratio was 0.41; the total retention rate of Ca, Mg, Si and P in the central region was 84.7% based on the corresponding total amount of the undesalted raw material.

[0032] The obtained seaweed carbonization precursor is fed into a continuous partitioned spiral propulsion pyrolysis furnace, which includes a devolatilization zone, a carbonization zone, a hot buffer zone and a heat preservation carbonization zone, and the zones are connected by double air lock valves. Nitrogen was used as the protective gas, the oxygen content in the furnace was controlled below 0.30 vol%, and the total nitrogen flow rate was 12 Nm³. 3 / h; The temperature in the devolatilization zone was set at 320℃, and the average residence time of the material was 40 min; the temperature in the carbonization zone was set at 580℃, and the average residence time of the material was 70 min. The hot seaweed char is transported to the surface deposition zone via a hot buffer zone. The material temperature is 525±10℃ when it enters the surface deposition zone. The hot seaweed char and condensed components generated in the first 30 minutes after startup are not included in the finished product statistics; after steady-state operation, only the hot seaweed char and condensed components corresponding to the time period of the same batch number KD-2026-01 are collected and returned accordingly.

[0033] The pyrolysis gas is first filtered by a cyclone separator, then by a 20μm sintered metal filter, before entering the segmented condensation system. The high-temperature condensation section uses a jacketed tube condenser, with the jacket heat transfer oil temperature controlled at 180±5℃. The obtained high-temperature condensate components are collected and their properties are analyzed: based on the dust-free pyrolysis gas entering the condenser, the mass yield is 6.8wt%; the Karl Fischer moisture content at 25℃ is 4.2wt%; the Brinell viscosity at 80℃ is 186 mPa·s; the residual carbon content under nitrogen conditions at 650℃ is 38.5wt%; based on the dry weight of the seaweed char after high-temperature carbonization, the total return amount of the high-temperature condensate components is 5.0wt%, of which the first stream accounts for 3.5wt% and the second stream accounts for 1.5wt%.

[0034] The first stream of material enters the evaporator and is then fed into the surface deposition zone at 235°C using nitrogen as a carrier gas, with a flow rate of 0.8 Nm³. 3 / h, contact time is 12min; after surface deposition, the seaweed char continues to enter the heat preservation carbonization section, and is kept at 560℃ for 25min; Afterward, the seaweed charcoal enters the countercurrent cooling section and is cooled to 240°C under nitrogen protection. The oxygen content at the outlet of the cooling section is controlled below 0.50 vol%. The second stream of fluid, kept at 165℃, is atomized through a dual-fluid nozzle and introduced into the pulverizing zone. The liquid flow rate is 0.225 kg / h, and the atomizing nitrogen flow rate is 0.35 Nm³. 3 / h, nozzle droplet D50 is 18μm.

[0035] The seaweed charcoal that forms a surface deposit is fed into an impact pulverizer via a double-lock valve. The rotor speed of the pulverizer is 5200 rpm, the processing capacity is 15 kg / h, and the oxygen content in the pulverizing chamber is controlled below 0.50 vol%. The pulverized product stays in the pulverizing zone for an average of 18 seconds and comes into contact with the second stream of material. The pulverized material enters the heat-insulating carbonization zone connected to the end of the carbonization section and is kept at 560℃ for 20 minutes. Then it is cooled to below 80℃ under a nitrogen atmosphere and classified by an air classifier to obtain seaweed charcoal powder. The D of the seaweed charcoal-ground powder 50 It is 8.9 μm, D 90 It is 24.8 μm.

[0036] Thirty particles with a diameter of 10–20 μm were collected from the final seaweed charcoal powder. Cross-sections were prepared using FIB-SEM and EDS linear scanning was performed. Simultaneously, surface analysis and depth analysis after 60 s argon ion sputtering were conducted using XPS. The thickness of the continuous layer on the particle surface, the O / C atomic ratio on the particle surface, the O / C atomic ratio after 60 s sputtering, and the ratio of Na content on the particle surface to Na content in the internal region were recorded. The thickness of the continuous surface layer is 0.62±0.11μm; the O / C atomic ratio on the particle surface is 0.121; the O / C atomic ratio after 60s sputtering is 0.187; the ratio of Na content on the particle surface to Na content in the internal region is 0.46. The open pore ratio, expressed as the ratio of the volume of connected pores measured by mercury intrusion porosimetry to the total pore volume calculated by helium gravity, was 33.4%. The oil absorption value, determined by the DBP absorption method, was 49.2 g / 100 g. The 24-hour moisture absorption rate, measured at 25°C and 75% relative humidity, was 1.93%. The water extraction conductivity, measured by adding 20.0 mL of deionized water to 1.000 g of sample and shaking at 25°C for 30 min, was 298 μS / cm.

[0037] The obtained seaweed charcoal powder was vacuum dried at 90℃ and -0.095MPa for 3 hours, and then metered and fed through a 100-mesh sieve. The polypropylene resin used is PPH-T30S, with a melt flow rate of 3.0 g / 10 min (230℃ / 2.16 kg). It is fed into a Φ35 mm co-rotating parallel twin-screw extruder through the main feed port, with a length-to-diameter ratio of 40:1, a screw speed of 280 rpm, and a total feed rate of 12 kg / h. The amount of seaweed charcoal powder added is 30wt%, which is added from the side feed port 12D away from the main feed port; the pre-wetting section is equipped with conveying thread elements and 30° staggered low-shear mixing elements; the dispersion and mixing section is equipped with 3 sets of 45° kneading elements, each set with a length of 4D; the homogenization section is equipped with conveying thread elements; the vacuum exhaust port is located 4D downstream of the homogenization section, and the vacuum degree is -0.082MPa; The temperatures for each temperature zone are set to 165℃, 175℃, 185℃, 190℃, 190℃, and 185℃ respectively. The molten material is extruded through a die head, cooled with water, and pelletized to obtain carbon-based masterbatch.

[0038] Set up comparative examples 1-1 to 1-4; Comparative Example 1-1: The sheet material was completely immersed in deionized water for 30 minutes, with a liquid-to-solid ratio of 8:1, and the other conditions were the same as in Example 1; Comparative Examples 1-2: The first logistics stream was eliminated, the second logistics stream remained at 1.5 wt%, and all other conditions were the same as in Example 1; Comparative Examples 1-3: The first stream of material was retained at 3.5 wt%, and the second stream of material was removed; the seaweed charcoal was cooled to 35±5℃ with nitrogen before being pulverized, and the other conditions were the same as in Example 1; Comparative Examples 1-4: The total amount and split ratio of the high-temperature condensed components were the same as in Example 1, but the returned components were replaced with the high-temperature condensed components obtained from another batch of kelp raw material KD-2026-02 under the same pyrolysis and condensation conditions. The other conditions were the same as in Example 1. Each group of samples was prepared independently in 3 batches, and the data listed in Table 1 are the average values ​​of the 3 batches.

[0039] Table 1: Detection data of Example 1 and Comparative Examples 1-1 to 1-4;

[0040] As shown in Table 1, in Example 1, the outer Na region + Extraction volume / central region Na + In terms of extraction amount, particle surface O / C atomic ratio, open pore ratio, DBP oil absorption value, 24 h moisture absorption rate, masterbatch 30 min filtration pressure difference increment, number of agglomerated particles with diameter greater than 50 μm, and continuous extrusion torque variation coefficient, it is at a relatively good level among the groups. Meanwhile, the total retention rate of Ca, Mg, Si and P in the central region of Example 1 was 84.7%, which was higher than that of Comparative Example 1-1 (55.9%), indicating that it maintained a high level of mineral retention in the central region while reducing the migratory salts in the outer layer and the surface polarity. After comparative examples 1-2 and 1-3 lacked surface deposition or crushing zone cross-sectional treatment, their particle surface continuous layer thickness, surface O / C, open pore ratio, oil absorption value and moisture absorption rate all deviated significantly from Example 1. The corresponding masterbatch filtration pressure difference, number of agglomerated particles and torque variation coefficient also increased simultaneously. When comparative examples 1-4 adopted the method of returning condensed components in different batches, their relevant indicators were better than some blank controls, but still did not reach the level of Example 1. Secondly, the water leaching conductivity of comparative examples 1-1 was lower than that of Example 1, indicating that the overall leaching desalination had a lower value in the overall leaching ion level, but its central area mineral retention rate, particle surface Na content / internal area Na content and masterbatch processing indicators were all lower than those of Example 1.

[0041] Example 2; Preparation of seaweed charcoal powder under lower limit parameter conditions; The methods used in this embodiment for measuring raw material moisture content, thickness, dividing the outer and central regions, element detection, particle size detection, pore structure detection, oil absorption value detection, moisture absorption rate detection, and water extraction conductivity detection are the same as those in Embodiment 1.

[0042] The central area of ​​the sheet material is the middle third of the thickness direction, and the outer layer is the area no more than 12.5% ​​of the sheet thickness from each of the two surfaces. The infiltration state in the central region was calibrated using parallel samples: 2.0% heavy water by volume was added to deionized water as a tracer solution, and after treatment under the same spraying conditions, the relative concentration of heavy water in the central region was determined by isotope ratio mass spectrometry. The method limit of quantitation is 0.20% of the initial concentration of the tracer solution. If the detection result in the central region is lower than this limit of quantitation, it is recorded as no tracer solution is detected in the central region.

[0043] Seaweed raw materials and surface-deep desalination; Select the same batch of rehydrated kelp stems with a wet basis moisture content of 18.0% to 18.5%. Cut the kelp stems into slices along the fiber direction. Measure the thickness of each slice at three locations: the middle and both ends. The thickness at all measurement points was 2.00 to 2.10 mm, with an average thickness of 2.05 mm.

[0044] The surface desalination at a limited depth uses an intermittent double-sided spray system; Each batch processes 4.80 kg of wet kelp, with a single layer covering an area of ​​1.00 m². 2 The surface density of the paving material is 4.80 kg / m³. 2 A nozzle is installed on each of the upper and lower sides, with a total flow rate of 0.82 L / min and a spraying pressure of 0.18 MPa. The distance from the nozzle to the material surface is 180 mm. The spraying time is controlled at 20.0–20.3 s, and the amount of spray liquid used per batch is 0.273–0.277 L.

[0045] The method limit of quantification is to spray parallel samples of heavy water tracers under the same conditions, with the relative concentration of heavy water in the central area being less than 0.20%. After spraying, the seaweed was centrifuged at 1800 r / min for 90 s and dried at 70 ℃ until the moisture content was no more than 7.5% to obtain the seaweed carbonization precursor.

[0046] The spraying device completes one batch of processing every 6 minutes, processing 10 batches of wet kelp per hour. The precursors, after spraying, centrifugation, and drying, enter the buffer silo and are fed into the pyrolysis furnace by a loss-in-weight feeder at a rate of 39.0 kg / h (dry basis).

[0047] Low-temperature devolatilization and high-temperature carbonization; The carbonized seaweed precursor enters a continuous partitioned spiral propulsion pyrolysis furnace, which is protected by nitrogen and the oxygen content is controlled below 0.30 vol%.

[0048] The measured temperature in the devolatilization zone was 280–283℃, and the average residence time of the material was 40 min; the measured temperature in the carbonization zone was 540–545℃, and the average residence time of the material was 70 min. After the pyrolysis furnace was running stably, the dry basis output of hot seaweed char was 15.0 kg / h; the seaweed char and condensed components obtained in the first 30 minutes of the start-up phase were not included in the sample of this example.

[0049] Collection and treatment of high-temperature condensed components; The pyrolysis gas passes through a cyclone separator and a sintered metal filter with a pore size of 20 μm before entering the segmented condensation system; the measured wall temperature of the high-temperature condensation section is 150–153 °C.

[0050] Based on the dry mass of the seaweed carbonization precursor entering the pyrolysis furnace, the yield of the high-temperature condensed component was 8.1%. The moisture content of the collected high-temperature condensed component was determined to be 7.3% by Karl Fischer method. It was then dehydrated under reduced pressure at 120℃ and gauge pressure of -0.080MPa for 30 min to reduce the moisture content to 1.8%, and then passed through a metal filter with a pore size of 100μm.

[0051] The apparent viscosity of the dehydrated high-temperature condensed component was measured at 155℃ using a Brookfield rotational viscometer, rotor No. 21, and 50 r / min, and was 31.4 mPa·s. On a dry basis, its C, H, and O content were 70.6%, 5.8%, and 19.4%, respectively, and its ash content was 2.6%. Under the conditions of nitrogen flow rate of 100 mL / min, heating rate of 10℃ / min, final temperature of 650℃, and holding at that temperature for 30 min, the residual carbon rate was measured to be 37.1%.

[0052] Based on the dry weight of the seaweed char after high-temperature carbonization, the total return amount of the high-temperature condensation components is 3.00%, corresponding to a continuous processing flow rate of 0.450 kg / h. Among them, the first stream consumption is 2.10%, with a flow rate of 0.315 kg / h; the second stream consumption is 0.90%, with a flow rate of 0.135 kg / h.

[0053] Surface deposition, hot grinding, and treatment of the ground surface; The first stream, maintained at 155–160°C, is atomized through a dual-fluid nozzle and then fed into the surface deposition zone. The atomizing nitrogen pressure is 0.60 MPa, and the median droplet size D... 50 It is 22μm; The screw conveyor speed is adjusted to ensure that the average residence time of the hot seaweed char in the surface deposition zone is 12 minutes. After deposition, the seaweed char enters the first heat-insulating carbonization zone and is kept at 540–545℃ for 25 minutes.

[0054] The seaweed char treated in the first heat preservation carbonization zone is cooled to 180-185℃ in the nitrogen countercurrent cooling section and enters the impact crusher through a double-lock valve. The rotor speed of the crusher is 5200r / min, the processing capacity is 15.0kg / h, the oxygen content in the crushing chamber is not higher than 0.50vol%, and the average residence time of the material is 18s.

[0055] The second stream, maintained at 155–160°C, is atomized by another dual-fluid nozzle and continuously introduced into the pulverizing zone. The median droplet size D... 50 It is 18μm; The pulverized product is fed into an indirect heating powder carbonization device via a closed screw conveyor. This device is equipped with three heating zones: 300–320℃, 420–440℃, and 540–545℃. The total time for the powder to pass through these three heating zones is 12 minutes, followed by a 20-minute holding period at 540–545℃. The oxygen content within the device is no higher than 0.50 vol%. The carrier gas outlet is connected sequentially to a cyclone separator and a 10 μm pore size metal filter, ensuring a powder collection loss rate of no more than 0.5%.

[0056] The powder after heat preservation and carbonization was cooled to below 80°C under a nitrogen atmosphere and then subjected to airflow classification to obtain seaweed charcoal powder; the D of the obtained powder 50 It is 9.6 μm, D 90 It is 26.2 μm.

[0057] The mass increment of carbonized deposited solids is calculated using the following formula: The increase in the mass of carbonized deposited solids = (dry basis mass of powder after treatment - dry basis mass of powder obtained without the return of high-temperature condensing components under the same conditions) ÷ dry basis mass of powder obtained without the return of high-temperature condensing components × 100%.

[0058] In this embodiment, the mass increment of carbonized deposited solids is 1.09%, which corresponds to a return amount of 3.00% of the high-temperature condensation component and a residual carbon content of 37.1%.

[0059] Detection of particle surface structure; Thirty particles with a diameter of 8–15 μm were randomly selected from each independent batch. Cross sections were prepared using FIB and detected using high-resolution transmission electron microscopy and STEM-EDS line scanning. The ratio of the length of the deposition area covering the particle perimeter to the total perimeter of the particle cross section was defined as the surface coverage rate. The thickness of the deposition layer was measured at eight equally spaced locations along the circumference of each particle, and the arithmetic mean of all measurement points was taken as the average deposition layer thickness.

[0060] XPS depth analysis uses Ar cluster ion sputtering with a sputtering rate of 10.0 nm / min calibrated with a standard carbon film. The O / C atomic ratio at the unsputtered surface and at a depth of 30 nm is recorded. During STEM-EDS detection, the region 0–20 nm from the particle surface is defined as the surface detection region, and the region 50–150 nm from the particle surface is defined as the internal detection region.

[0061] The proportion of open pores is calculated using the following formula: Open pore proportion = Volume of connected pores measured by mercury intrusion porosimetry ÷ Total pore volume calculated from envelope density and helium true density × 100%.

[0062] The DBP oil absorption value was tested using 10.000g of powder. The DBP dropping rate was 4.0mL / min. The amount of DBP added was calculated based on the mixer torque reaching 0.50N·m and maintained for 10s.

[0063] The 24-hour moisture absorption rate was tested under the following conditions: the powder was first vacuum dried at 105℃ and gauge pressure -0.095MPa for 4 hours, 2.000g of sample was weighed and placed in an environment of 25℃ and relative humidity of 75% for 24 hours, and the result was calculated as a percentage of the increase in mass to the initial dry powder mass.

[0064] The detection conditions for water extraction conductivity are as follows: Weigh 1.000g of powder, add 20.0mL of deionized water, shake at 25℃ and 200r / min for 30min, filter through a 0.45μm filter membrane and measure, and convert to 25℃.

[0065] Scale settings; Comparative Example 2-1: The spraying time was adjusted to 18.0–18.3 s, while other conditions remained the same as in Example 2; Comparative Example 2-2: The spraying time was adjusted to 15.0–15.3 s, while other conditions were the same as in Example 2; In Comparative Examples 2-3, the total return amount of the high-temperature condensing components was adjusted to 2.80%, of which the first stream was 1.96% and the second stream was 0.84%, and other conditions were the same as in Example 2; In Comparative Examples 2-4, the total amount of high-temperature condensed components returned was adjusted to 2.50%, with the first stream being 1.75% and the second stream being 0.75%, and other conditions being the same as in Example 2. Example 2 and each comparative example were prepared independently in 3 batches; the batch test results in Table 2 are expressed as average values; the microstructure data were obtained by testing 30 particles in each batch, and 8 positions were detected for each particle.

[0066] To evaluate the lower limit conditions, the following powder quality control values ​​were preset: Na in the outer layer region + Extraction volume and Na content in the central region +The ratio of extraction amount is not higher than 0.60, the total retention rate of Ca, Mg, Si and P in the central area is not lower than 85%, the particle surface coverage is not lower than 80%, the O / C atomic ratio on the particle surface is not higher than 0.160, the proportion of open pores is not higher than 45%, the DBP oil absorption value is not higher than 65g / 100g, the 24h moisture absorption rate is not higher than 3.0%, and the water extraction conductivity is not higher than 400μS / cm.

[0067] Table 2: Preparation parameters and test results of Example 2 and Comparative Examples 2-1 to 2-4

[0068] It should be noted that "<0.20" in the table indicates that the detection result is below the limit of quantitation for tracer detection methods.

[0069] Table 2 shows that, under the conditions of 20s spraying and 3.00% high-temperature condensation component return in Example 2, the tracer in the central region was below the limit of quantitation, and the Na in the outer and central regions was... + The extraction ratio was 0.58, and the total mineral retention rate in the central area was 86.9%, both of which were within the preset control range. Compared to Example 2, the total mineral retention rates in the central regions of Comparative Examples 2-1 and 2-2 were 88.1% and 89.2%, respectively, but the Na content in the outer and central regions was significantly lower. + The extraction ratios were 0.64 and 0.72, respectively, and the water extraction conductivity was 432 μS / cm and 489 μS / cm, respectively, showing a combination of high mineral retention but failure to simultaneously meet the outer layer migration salt control value. The desalination indices of Comparative Examples 2-3 and 2-4 were similar to those of Example 2, but the particle surface coverage was 76.4% and 68.1%, respectively; the surface O / C atomic ratio was 0.166 and 0.177, respectively; the open pore ratio was 47.6% and 51.9%, respectively; and the DBP oil absorption value and 24h moisture absorption rate both exceeded the preset control values.

[0070] Example 3; Preparation of seaweed charcoal powder under upper limit parameter conditions; The stems of rehydrated kelp from the same batch were selected, with a wet basis moisture content of 18.0% to 18.5%. Thirty pieces of kelp stems were randomly selected from each batch, and the thickness was measured once at the middle and both ends of each piece. The thickness of the 90 measuring points was 5.90 to 6.00 mm, with an average thickness of 5.96 mm. The kelp stems were cut into slices along the fiber direction, with 6.00 kg processed per batch, and laid in a single layer on an effective area of ​​1.20 m². 2 On the polytetrafluoroethylene mesh belt.

[0071] Surface spraying was performed using dual nozzles (upper and lower), with a combined flow rate of 0.82 L / min and a spraying pressure of 0.18 MPa. The distance from the nozzle to the material surface was 180 mm. The desalination solution was 25°C deionized water, and the spraying time was 90.0–90.5 s. The volume of spray solution used per batch was 1.23–1.24 L. Parallel samples were taken within 5 s after spraying and frozen with liquid nitrogen, with the middle third of the thickness direction designated as the central area. The depth-limited spraying was calibrated using heavy water horizontal sampling. The heavy water volume fraction in the tracer spray solution was 2.00%. The heavy water content in the central region was determined using isotope ratio mass spectrometry. The natural deuterium abundance in the unsprayed kelp central region was used as a blank value, and the relative concentration of the tracer in the central region was calculated using the following formula: The relative concentration of tracer in the central region = (heavy water measurement value in the central region - blank value) ÷ (heavy water measurement value in the spray solution - blank value) × 100%.

[0072] The limit of quantitation for this method is 0.20%; the relative concentration of the tracer in the central region of Example 3 is lower than the limit of quantitation for this method. The sprayed material was centrifuged at 1800 r / min for 90 s and dried at 70 ℃ until the moisture content was no more than 7.5% to obtain the seaweed carbonization precursor.

[0073] The seaweed carbonization precursor was fed into a continuous partitioned spiral propulsion pyrolysis furnace at a dry basis rate of 48.0 kg / h. The set temperature of the devolatilization zone was 360℃, the actual measured temperature was 357~360℃, and the average residence time was 40 min; the set temperature of the carbonization zone was 620℃, the actual measured temperature was 615~620℃, and the average residence time was 70 min. The furnace is protected by nitrogen, and the oxygen content is no higher than 0.30 vol%. After stable operation, the dry basis output of hot seaweed char is 18.0 kg / h.

[0074] The pyrolysis gas passed sequentially through a cyclone separator and a sintered metal filter with a pore size of 20 μm, and then entered the segmented condensation system. The wall temperature of the high-temperature condensation section was set at 220℃, and the actual measured wall temperature at each temperature measuring point was 217~220℃; the mass yield of the collected high-temperature condensation components was 5.4% based on the dry weight of the seaweed carbonization precursor.

[0075] The high-temperature condensed component was dehydrated under reduced pressure for 30 minutes at 120℃ and a gauge pressure of -0.080MPa, and then passed through a metal filter with a pore size of 25μm. The actual moisture content of the high-temperature condensed component entering the return pipeline was 0.8%, and the apparent viscosity was measured to be 42mPa·s at 180℃ using a rotational viscometer. Based on the original mass of the treated components, under the conditions of nitrogen flow rate of 100 mL / min, heating rate of 10℃ / min, final temperature of 650℃ and holding at that temperature for 30 min, the mass fraction of residual char was 43.8%.

[0076] The total amount of high-temperature condensed components returned was 8.00% of the dry weight of the hot seaweed char, and the continuous return flow rate was 1.440 kg / h. The first stream of material used was 5.60% of the dry weight of the hot seaweed charcoal, with a flow rate of 1.008 kg / h; the second stream of material used was 2.40% of the dry weight of the hot seaweed charcoal, with a flow rate of 0.432 kg / h.

[0077] The first stream of fluid is transported to the surface deposition area via a heated pipeline, with the pipeline temperature maintained at 180–185°C; the liquid orifice diameter of the atomizing nozzle is 0.80 mm, the width of the annular gas channel is 1.20 mm, the atomizing nitrogen pressure is 0.55 MPa, and the gas-liquid mass ratio is 0.65. The droplet density (D) was measured online using a 180℃ constant-temperature measuring chamber and a laser particle size analyzer. 50 16μm, D 90 It is 34μm; Adjust the screw conveyor speed to make the average residence time of seaweed char in the surface deposition zone 12 min, and then keep it at 615-620℃ for 25 min for carbonization.

[0078] After the first stream of seaweed charcoal is processed, it is cooled to 296-300℃ by countercurrent nitrogen. The actual solid flow rate when it enters the pulverizer is 18.40-18.45 kg / h. The pulverizing device is an impact pulverizer with a rated processing capacity of 30 kg / h, a rotor speed of 5200 r / min, and an oxygen content in the pulverizing chamber of no more than 0.30 vol.

[0079] The second stream, maintained at 180–185°C, is introduced into the pulverizing zone through a dual-fluid nozzle with a liquid orifice diameter of 0.60 mm. The atomizing nitrogen pressure is 0.60 MPa, the gas-liquid mass ratio is 0.80, and the droplet density (D) is measured online. 50 13μm, D 90 The particle size is 28 μm. The pulverized product enters the indirect heating powder carbonization device via a closed screw conveyor and passes through three heating zones in sequence: 420–430℃, 515–525℃, and 615–620℃. The total residence time in the heating zones is 10 min, followed by holding at 615–620℃ for 20 min.

[0080] The powder carbonization device maintains a gauge pressure of -100 to -300 Pa and an oxygen content of no more than 0.30 vol%; the exhaust end is connected in sequence to a cyclone separator and a metal filter with a pore size of 5 μm, and the collected fine powder is returned to the product collection system; The carbonized powder was cooled to below 80°C under a nitrogen atmosphere, and then subjected to air classification to obtain seaweed charcoal powder, whose D... 50 It is 8.3 μm, D 90 It is 22.9 μm.

[0081] Determination of the mass increment of carbonized deposited solids; The treatment group (with the return of high-temperature condensing components) and the blank group (without the return of high-temperature condensing components) were run continuously for 60 minutes. The graded products, cyclone-separated fine powder, filter fine powder, and recyclable equipment sediments were collected. The total dry basis mass m1 of the product in the treatment group, the ash mass fraction A1 of the treatment group, and the ash mass fraction A0 of the blank group were measured.

[0082] Calculate the equivalent mass m0 of the original seaweed char in the treatment group using the following formula: m0 = m1 × A1 ÷ A0; The mass increment of carbonized deposited solids is calculated using the following formula: The mass increment of carbonized deposited solids = (m1 - m0) ÷ m0 × 100%; The carbonized deposited solids mass increment in Example 3 was 3.24%; based on a return rate of 8.00% and a residual carbon mass fraction of 43.8%, the theoretical maximum residual carbon increment was 3.504%, and the apparent carbon retention rate was 92.5%.

[0083] Detection of particle surface structure; Based on the laser particle size analysis results, the powder was divided into four particle size ranges: less than 7μm, 7–15μm, 15–30μm, and greater than 30μm. For each independent batch, 20 particles were randomly selected from each particle size range, for a total of 80 particles tested. A total of 240 particles were tested across the three batches. Microscopic samples are randomly selected by an automated stage according to preset coordinates, without manual screening based on particle appearance. Thin sections of particle cross-sections were prepared using focused ion beam microscopy, and the surface region was then examined using scanning transmission electron microscopy and electron energy loss spectroscopy. Blank carbon particles without high-temperature condensation components were used as a reference. When the difference between the carbon K-edge π* / σ* peak intensity ratio in the cross-sectional edge region and the mean of the blank group was not less than 3 times the standard deviation of the blank group, and the continuous width of the region along the normal direction was not less than 10 nm, it was recorded as a carbonization deposition region.

[0084] Twelve measuring points are set at equal angles along the circumference of each particle cross section; measuring points that meet the above criteria are recorded as covered points, and those that do not are recorded as uncovered points; the surface coverage rate is the percentage of the number of covered points to the total number of measuring points; the circumferential equivalent average sediment layer thickness is calculated based on all measuring points, and the thickness of uncovered locations is recorded as 0. The results for each particle size segment are weighted according to the volume fraction of the corresponding particle size segment to obtain the weighted coverage and weighted equivalent average thickness of the entire batch of powder.

[0085] The open-pore ratio is calculated as the ratio of the volume of the connected pores measured by the mercury intrusion porosimetry to the total pore volume calculated based on the envelope density and the true density of helium. Agglomerated particles were statistically analyzed using melt-pressed tablet microscopy, with 20 particles of 10 mm² randomly selected from each batch. 2 The field of view was recorded, and the number of particles with an equivalent circle diameter greater than 50 μm was recorded. The angle of repose was determined using the fixed funnel method, with 5 parallel tests per batch. The residue on the 75 μm sieve was calculated after vibrating and sieving 100.0 g of sample for 10 min.

[0086] Scale settings The spraying times for Comparative Examples 3-1, 3-2, and 3-3 were 95 s, 100 s, and 105 s, respectively, and the other conditions were the same as in Example 3.

[0087] The total amount of high-temperature condensed components returned in Comparative Examples 3-4, 3-5 and 3-6 were 8.20%, 8.50% and 9.00%, respectively. The mass ratio of the first stream to the second stream was maintained at 7:3. Other conditions were the same as in Example 3.

[0088] The pulverizing inlet temperatures of Comparative Examples 3-7, 3-8, and 3-9 were 303–305°C, 308–310°C, and 312–315°C, respectively, and other conditions were the same as in Example 3.

[0089] Comparative Examples 3-10 introduced only the first stream, accounting for 8.00% of the dry mass of the hot seaweed char, into the surface deposition zone; Comparative Examples 3-11 introduced only a second stream of material, accounting for 8.00% of the dry weight of the hot seaweed charcoal, into the pulverizing zone; Comparative Examples 3-12 did not return the high-temperature condensed components. All other conditions were the same as in Example 3.

[0090] Example 3 and each comparative example were prepared independently in 3 batches. The data in the table are expressed as average values. Key indicators were analyzed by one-way ANOVA and Dunnett's multiple comparison test, with p < 0.05 as the statistical standard for differences between groups. Table 3A: Detection Results of Adjacent Conditions for Spraying Time Limit

[0091] Table 3B: Detection Results of Upper Limit of High-Temperature Condensed Component Return Amount under Adjacent Conditions

[0092] Table 3C: Detection Results of Upper Limit of Crushing Inlet Temperature under Adjacent Conditions

[0093] Table 3D: Comparison Results of Two Logistics Stream Settings

[0094] As shown in Table 3A, under the 90s spraying condition, the heavy water concentration in the central region was below the limit of quantification, and the total mineral retention rate in the central region was 81.8%. When the spraying time was increased to 95s, 100s, and 105s, the relative concentrations of heavy water in the central region were 0.46%, 2.18%, and 7.62%, respectively, and the total mineral retention rates in the central region were 79.6%, 75.1%, and 70.4%, respectively. The 90s condition corresponds to the outer Na+ layer... + Combined data of leaching ratio of 0.36 and mineral retention rate in the central area of ​​over 80%.

[0095] In Table 3B, after the return amount was increased from 8.00% to 8.20%, D 90 The size increased from 22.9 μm to 25.8 μm, and the number of agglomerated particles increased from 3.8 per 10 mm. 2 Increased to 6.4 per 10mm 2 Under conditions of 8.50% and 9.00%, D 90 The angle of repose and the amount of residue on the sieve continue to increase.

[0096] In Table 3C, the solid mass increments of each group are similar, but after the crushing inlet temperature exceeds 300℃, the surface coverage, equivalent layer thickness, surface O / C, open hole ratio, oil absorption value and moisture absorption rate show continuous differences.

[0097] In Table 3D, when both streams are set simultaneously, the surface coverage rate is 91.4%, which is higher than that of setting only the first stream, setting only the second stream, and the no-return group; its opening ratio, oil absorption value, moisture absorption rate, and D... 90 The number of agglomerated particles was lower than that of the three control groups; the above data correspond to the powder structure and performance combination under the conditions of 90s spraying, 8.00% return amount, 296-300℃ pulverization inlet temperature, and first and second stream partition introduction.

[0098] Example 4; Preparation of seaweed charcoal powder under different seaweed raw materials, material forms and return conditions; This embodiment sets up embodiments 4A to 4D; Example 4A and Example 4B use the same seaweed raw materials and material forms, only the conveying states of the first and second streams of material are exchanged; Example 4A and Example 4C use the same material form and logistics state, only the type of seaweed raw material is changed; Example 4C and Example 4D use the same seaweed raw materials and logistics conditions, only the material form is changed.

[0099] In this embodiment, the homologous high-temperature condensation component refers to the high-temperature condensation component that has the same raw material batch number as the seaweed char that is returned to the treatment and is collected from the pyrolysis gas generated during the corresponding stable operating period. The seaweed char and condensate obtained in the first 30 minutes after the pyrolysis system is started are not used as test samples; after stable operation, the seaweed char and high-temperature condensate are put into the hot buffer chamber and the heat-traced storage tank respectively according to the raw material batch number and the time period of generation.

[0100] The vaporized state refers to the condensable vapor stream formed after the high-temperature condensed components are processed by a scraped film evaporator. After passing through a 5μm demister, the mass fraction of droplet entrainment in this stream, measured by the isokinetic sampling method, is no higher than 0.50%. Unvaporized residual liquid is collected separately and is not included in the actual return amount; the actual return amount of vaporized stream is calculated based on the difference between the evaporator feed rate and the amount of unvaporized residual liquid.

[0101] Atomized state refers to the droplet stream formed by high-temperature condensed components through a dual-fluid nozzle. The droplet size is determined using a constant-temperature laser particle size measurement chamber. 90 Not exceeding 40 μm. The return volume of the surface deposition zone and the pulverization zone is calculated based on the actual mass of the high-temperature condensed components entering the corresponding treatment zone.

[0102] In Example 4A, the stems of wakame seaweed from batch number WD-01 were selected, rehydrated to a wet basis moisture content of 18.0%–18.5%, and then cut and granulated into granular material. Three-dimensional images of the granules were obtained using micro-CT, and the diameter of a sphere with the same volume as the granule was used as the volumetric sphere diameter; 100 granules were randomly selected from each batch, and the volumetric sphere diameter was 3.80–4.20 mm.

[0103] For granular materials, the area at a distance of no more than 0.40 mm from the normal to the outer surface of the particle is defined as the outer layer; the spherical area with a radius of 0.60 mm centered on the centroid of the particle is defined as the central area; the stratified sampling location is determined according to the micro-CT coordinates, and the separation is achieved by cryosectioning and microsampling.

[0104] Each batch processes 4.80 kg of wet material, laid in a single layer over an effective area of ​​1.00 m². 2 On the mesh belt, 25℃ deionized water is sprayed from upper and lower double nozzles with a total flow rate of 0.82L / min, a spray pressure of 0.18MPa, a spray time of 60.0~60.5s, and a desalination liquid dosage of 0.170~0.172L / kg wet material.

[0105] Parallel samples for heavy water tracers were treated with a spray solution containing 2.00% heavy water by volume. The samples were frozen with liquid nitrogen within 5 seconds after spraying. The heavy water content in the central region was determined by isotope ratio mass spectrometry, using the natural deuterium abundance as a blank value. The ratio of the heavy water concentration in the central region to the initial heavy water concentration in the spray solution was less than the limit of quantitation of the method (0.20%).

[0106] The sprayed material is centrifuged at 1800 r / min for 90 s and dried at 70℃ until the moisture content is no higher than 7.5%. The resulting precursor is devolatilized at 320–325℃ for 40 min under a nitrogen atmosphere, and then carbonized at 575–580℃ for 70 min. The oxygen content in the furnace is no higher than 0.30 vol%. During stable operation, the dry basis output of hot seaweed char is 15.0 kg / h.

[0107] The pyrolysis gas passed sequentially through a cyclone separator and a 20μm sintered metal filter before entering a segmented condensation system. The measured wall temperature of the high-temperature condensation section was 180–183℃. The resulting high-temperature condensed component was dehydrated under reduced pressure for 30 min at 120℃ and a gauge pressure of -0.080 MPa, and then passed through a 25μm metal filter. The actual moisture content of the component entering the return pipeline was 1.1%, and the apparent viscosity at 170℃ was 32.4 mPa·s. Based on the original mass of the treated component, under the conditions of a nitrogen flow rate of 100 mL / min, a heating rate of 10℃ / min, a final temperature of 650℃, and a holding time of 30 min, the residual carbon mass fraction was 40.6%.

[0108] The actual total return amount of the high-temperature condensation component is 5.00% of the dry mass of seaweed char, i.e., 0.750 kg / h; of which, the actual return amount of the first stream is 3.50%, i.e. 0.525 kg / h; and the actual return amount of the second stream is 1.50%, i.e. 0.225 kg / h.

[0109] The first stream of fluid is maintained at 170–175°C and atomized through a dual-fluid nozzle with a liquid orifice diameter of 0.70 mm. The atomizing nitrogen pressure is 0.55 MPa, and the gas-liquid mass ratio is 0.70. Droplet D 50 It is 17μm, D 90 The thickness is 39 μm. The first stream of material is continuously introduced into the surface deposition zone, where the seaweed char has an average residence time of 12 min, followed by carbonization at 575–580 °C for 25 min.

[0110] The second stream is processed by a scraped-film evaporator at 245℃ and 30kPa absolute pressure, achieving a vaporization mass fraction of 88.6% during stable operation. To ensure an actual vaporized stream flow rate of 0.225 kg / h entering the pulverizing zone, the evaporator feed rate is controlled at 0.254 kg / h, and the unvaporized residual liquid flow rate is 0.029 kg / h. The vaporized stream is then transported via a 5μm demister and a 250℃ heated pipeline, with a droplet entrainment mass fraction of 0.32%.

[0111] The seaweed charcoal, after being processed by the first stream, is cooled to 238–242°C under a nitrogen atmosphere and enters an impact pulverizer with a rated processing capacity of 25 kg / h at a solid flow rate of 15.30–15.35 kg / h. The rotor speed of the pulverizer is 5200 r / min, and the oxygen content in the pulverizing chamber is not higher than 0.30 vol%. The second gasified stream is continuously introduced into the pulverizing zone.

[0112] The pulverized product enters the powder heat preservation and carbonization device via a closed screw conveyor, and is heated to 555-560°C within 10 minutes, and then kept at that temperature for 20 minutes. The oxygen content inside the device is no higher than 0.30 vol%. A cyclone separator and a 5 μm metal filter are installed at the exhaust end. The collected fine powder is returned to the product collection system. The powder is cooled to below 80°C by nitrogen and airflow classification is performed to obtain seaweed charcoal powder of Example 4A.

[0113] In Example 4B, the seaweed raw material, particle morphology, desalination conditions, pyrolysis conditions, properties of high-temperature condensation components, total return amount, and split ratio are all the same as in Example 4A.

[0114] In Example 4B, the first stream was set to a vaporized state, and the second stream was set to an atomized state. The first stream was treated by a scraped film evaporator at 248°C and 30 kPa absolute pressure, with a vaporization mass fraction of 87.4%. To ensure that the actual vaporized stream entering the surface deposition zone reached 0.525 kg / h, the evaporator feed rate was controlled at 0.601 kg / h, and the unvaporized residual liquid flow rate was 0.076 kg / h. After demisting, the droplet entrainment mass fraction was 0.35%.

[0115] The second stream was maintained at 170–175°C and atomized using a dual-fluid nozzle with a liquid orifice diameter of 0.60 mm. The atomizing nitrogen pressure was 0.60 MPa, the gas-liquid mass ratio was 0.80, and the droplet D... 50 It is 14μm, D 90 The thickness is 31 μm, the actual return rate is 0.225 kg / h, and the other operating conditions are the same as in Example 4A.

[0116] In Example 4C, the stem axis and air bladder of Sargassum fusiforme with batch number SF-01 were selected, and after rehydration, they were granulated into granular materials with an equal volume sphere diameter of 3.80-4.20 mm. The division of the outer and central regions of the particles, the spray desalination conditions, the pyrolysis temperature, the condensation wall temperature, the total amount of return, the diversion ratio, the first atomization state, the second gasification state, the pulverization temperature, and the recarbonization conditions were all the same as in Example 4A.

[0117] The homologous high-temperature condensate after treatment in Example 4C had a moisture content of 1.0%, an apparent viscosity of 31.2 mPa·s at 170°C, and a nitrogen residue mass fraction of 41.3% at 650°C. The vaporization mass fraction of the second stream at 245℃ and 30kPa absolute pressure is 89.1%. The feed rate to the evaporator is controlled based on the actual mass of 0.225kg / h entering the crushing zone.

[0118] In Example 4D, the same batch of Sargassum raw material as in Example 4C was used and processed into sheet material with a thickness of 3.80-4.20 mm. 30 sheets were randomly selected from each batch, and the thickness of each sheet was measured at the middle and both ends. All measuring points were within the above range.

[0119] For sheet-like materials, the area no more than 0.50 mm from each of the two main surfaces is defined as the outer layer, and the middle third of the thickness direction is defined as the central layer. The first stream of material is atomized, the second stream is gasified, and the remaining desalination, pyrolysis, deposition, crushing, and heat preservation carbonization conditions are the same as in Example 4C.

[0120] Comparative Example 4-1 used wakame seaweed granules of the same batch and morphology as in Example 4A, but replaced the homologous high-temperature condensation component with a heterologous high-temperature condensation component collected from rice husk pyrolysis gas at a wall temperature of 180–183°C. After dehydration under reduced pressure, filtration, and graded blending, the component had a moisture content of 1.1%, an apparent viscosity of 32.9 mPa·s at 170°C, and a nitrogen residue mass fraction of 40.4% at 650°C. The total return volume, the ratio of the first and second streams, the atomization conditions of the first stream, and the gasification conditions of the second stream were all the same as in Example 4A.

[0121] Comparative Example 4-2 used the same batch and morphology of wakame seaweed particles as Example 4A, without feeding back high-temperature condensing components to the surface deposition zone and pulverizing zone. The remaining desalination, pyrolysis, pulverization, heat preservation carbonization and grading conditions were the same as in Example 4A.

[0122] Detection and calculation methods; The mass increment of carbonized deposited solids was calculated using the ash conservation method. Graded products, cyclone fine powder, filter fine powder, and recyclable equipment sediments were collected from the treated group and the non-returned group, respectively. The equivalent mass of the original seaweed char was calculated using the final dry basis total mass of the treated group, the ash mass fraction of the treated group, and the ash mass fraction of the non-returned group. The mass increment of carbonized deposited solids was the percentage of the difference between the final dry basis total mass of the treated group and the equivalent mass of the original seaweed char to the equivalent mass of the original seaweed char.

[0123] The theoretical residual carbon increment is calculated as the product of the actual return amount and the actual return material residual carbon mass fraction; the apparent carbon retention rate is the ratio of the measured carbonized deposit solid mass increment to the theoretical residual carbon increment.

[0124] The final powder was tested according to four particle size ranges: less than 7 μm, 7–15 μm, 15–30 μm, and greater than 30 μm. For each batch, 20 particles were randomly selected from each particle size range, cross-sections were prepared using focused ion beam microscopy, and the surface region was identified by scanning transmission electron microscopy and electron energy loss spectroscopy. Twelve measuring points were set at equal angles along the circumference of each particle cross section; the thickness of the location where no deposition area was detected was recorded as 0. The results for each particle size range are weighted according to the particle size volume fraction to obtain the weighted surface coverage and circumferential equivalent average sediment thickness.

[0125] The open-pore ratio is the ratio of the volume of connected pores measured by mercury intrusion porosimetry to the total pore volume calculated based on the envelope density and the true density of helium. The 24-hour moisture absorption rate was measured at 25°C and 75% relative humidity. Aggregated particles were statistically analyzed using tablet microscopy, with 20 particles of 10 mm² per batch being tested. 2 The field of view was used to record the number of particles with an equivalent circle diameter greater than 50 μm; Each group prepared 3 batches independently, and some results are expressed as mean ± standard deviation.

[0126] Table 4-1: Main process settings for each implementation group and comparative example

[0127] Table 4-2: Detection results of different seaweed raw materials, material forms, and logistics states

[0128] As shown in Table 4-2, Examples 4A and 4B used the same wakame seaweed particles, only exchanging the gasified and atomized state configurations of the two streams. Their weighted surface coverage rates were 88.8% and 87.9%, respectively; their surface O / C atomic ratios were 0.130 and 0.132, respectively; and their open pore ratios were 34.0% and 34.8%, respectively. All results were in a similar range. Examples 4A and 4C maintained the same particle morphology and material flow configuration. After replacing the seaweed raw material with Sargassum fusiforme, the total mineral retention rates in the central area were 83.6% and 81.9%, respectively, and the weighted surface coverage rates were 88.8% and 86.5%, respectively. Examples 4C and 4D only changed the morphology of Sargassum material. The differences in coverage, sediment thickness, O / C ratio, open pore ratio, oil absorption value, and moisture absorption rate between the two groups were all less than 6% of the average values ​​of the corresponding indicators. Comparative Example 4-1 used heterologous rice husk condensation components, with a coverage rate of 72.3%, D 90 The size is 31.9 μm, and the number of aggregated particles is 10.7 / 10 mm. 2 ; Comparative Example 4-2 did not have a return logistics system, and its coverage rate was 11.6%, the proportion of open holes was 59.5%, and the oil absorption value was 97.2g / 100g; Examples 4A to 4D collectively cover different seaweed sources, granular and sheet-like morphologies, and cross-configurations of two streams in vaporized and atomized states.

[0129] Example 5; Carbon-based masterbatch was prepared by grinding seaweed charcoal; In this embodiment, carbon-based masterbatch was prepared using seaweed charcoal calcination powder obtained in Example 1; the D of the seaweed charcoal calcination powder used was... 50 It is 8.9 μm, D 90 The micrometer is 24.8 μm, the DBP oil absorption value is 49.2 g / 100 g, and the 24-hour moisture absorption rate is 1.93%.

[0130] Set up Embodiment 5A and Embodiment 5B; Example 5A uses homopolymer polypropylene as the carrier resin to evaluate the processing performance of seaweed charcoal powder in non-polar polyolefins. Example 5B uses extrusion-grade polylactic acid as the carrier resin to evaluate the processing performance of seaweed charcoal powder in biodegradable polyester.

[0131] Seaweed charcoal powder was vacuum dried at 90℃ and a gauge pressure of -0.095MPa for 4 hours, with a moisture content not exceeding 0.15%. It was then passed through a vibrating screen with a pore size of 150μm and metered by a twin-screw loss-in-weight side feeder. Polypropylene was dried at 80℃ for 2 hours. Polylactic acid was vacuum dried at 80℃ and a gauge pressure of -0.095MPa for 6 hours, with a moisture content not exceeding 0.03%.

[0132] A co-rotating parallel twin-screw extruder with a screw diameter of 35mm and a length-to-diameter ratio of 44:1 is used. The carrier resin is added through the main feed port, forming a continuous polymer melt in the main plasticizing section from 0 to 14D; the seaweed charcoal powder is added through the side feed port at position 14D, and the seaweed charcoal powder accounts for 30.0% of the total mass of the masterbatch. The total feed rate is 12.0 kg / h, and the screw speed is 280 r / min.

[0133] Sections 14–20D are pre-wetting sections, equipped with a forward conveying threaded element and a set of forward kneading elements with a length of 2D and a staggered angle of 30°; Sections 20–30D are dispersion and mixing sections, equipped with two sets of forward kneading elements, each with a length of 3D and a staggered angle of 45°, with a forward conveying threaded element of 1D between the two sets of kneading elements; Sections 30–38D are homogenization sections, equipped with a forward conveying threaded element and a set of mixing elements with a length of 2D and a staggered angle of 30°; the vacuum exhaust port is located at position 39D, and the vacuum degree during stable operation is -0.082 to -0.087 MPa.

[0134] In Example 5A, the temperatures of the six barrel sections were set sequentially to 165°C, 175°C, 185°C, 190°C, 190°C, and 185°C. In Example 5B, the temperatures of the six-section barrel were set sequentially to 150°C, 160°C, 170°C, 175°C, 175°C, and 170°C. The molten mixture was extruded through a double-hole circular die, cooled with circulating water at 15-20°C, and cut into carbon-based masterbatches with a length of 3.0-3.5 mm after being dehydrated by an air knife. Each group ran continuously for 60 minutes.

[0135] Comparative Examples 5-1 to 5-3 were set up, all using the same polypropylene resin, seaweed charcoal powder addition ratio, screw structure, and extrusion conditions as Example 5A.

[0136] Comparative Example 5-1 uses ordinary pyrolytic seaweed char powder; this powder is obtained by carbonizing kelp at 580℃ and cold pulverizing after whole-body water washing, without high-temperature condensation component return treatment.

[0137] Comparative Example 5-2 used activated pore-enhancing seaweed char powder; ordinary pyrolytic seaweed char was activated with steam at 800℃ for 30 minutes, and then subjected to cold pulverization and airflow classification.

[0138] Comparative Examples 5-3 used seaweed charcoal powder that had not undergone pulverization and cross-sectional treatment; the preparation conditions of this powder were the same as in Example 1, but a second high-temperature condensation component was not introduced into the pulverization zone.

[0139] After air classification, the powders in each comparative example, D 50 Controlled within 8.7–9.2 μm, D 90 The sample size was controlled at 24.0–26.0 μm, and dried, sieved, and side-fed under the same conditions as in Example 5A.

[0140] The side feed rate variation coefficient is calculated based on the instantaneous feed rate recorded per second during 30 minutes of stable operation; the extrusion torque variation coefficient is calculated based on the torque recorded by the main unit during the same period. The filtration pressure difference was measured using three layers of filters: 80 mesh, 120 mesh, and 80 mesh. The pressure difference at the start of stable operation and after 30 minutes was recorded. The masterbatch was hot-pressed into 0.5 mm thick sheets, and 20 sheets with an area of ​​10 mm² were randomly selected from each batch for testing. 2 The field of view was used to count the number of aggregated particles with an equivalent circle diameter greater than 50 μm. The 24-hour moisture absorption rate of the masterbatch was measured in an environment of 25℃ and 75% relative humidity; the water extraction conductivity was measured by adding 5.000g of masterbatch to 50.0mL of deionized water and shaking at 25℃ for 2 hours.

[0141] Each group prepared 3 batches independently, and the data in Table 5 is the arithmetic mean of the test results of the 3 batches.

[0142] Table 5: Results of Processing Performance Testing of Carbon-Based Masterbatch

[0143] It should be noted that the melt flow rates of PP masterbatch and PLA masterbatch are determined according to their respective applicable test temperatures and load conditions, and no direct numerical comparison is made between the two.

[0144] As shown in Table 5, the coefficient of variation of side feed rate, coefficient of variation of extrusion torque, and 30-minute filtration pressure difference increment of Example 5A are 2.8%, 4.8%, and 0.18 MPa, respectively, all of which are lower than those of the three PP comparative examples. The number of agglomerated particles in Example 5A was 3.2 per 10 mm. 2 Comparative Examples 5-1, 5-2, and 5-3 had 17.6 samples per 10 mm. 2 23.5 pieces / 10mm 2 and 12.9 per 10mm 2 Example 5A corresponds to a lower level of coarse particle agglomeration; the activated pore-forming powder has a higher filtration pressure difference, agglomerated particle number and moisture absorption rate than the three comparative examples, and its masterbatch melt mass flow rate is 0.82 g / 10 min, which is lower than 1.82 g / 10 min in Example 5A. Comparative Example 5-3, which did not undergo pulverization treatment, had higher torque variation coefficient, filtration pressure difference increment, number of agglomerated particles, moisture absorption rate, and water leaching conductivity than Example 5A. In Example 5B, when PLA carrier was used, the side feed rate variation coefficient was 3.6%, the torque variation coefficient was 6.2%, the filtration pressure differential increment was 0.27 MPa, and the machine ran continuously for 60 minutes without stopping. Examples 5A and 5B cover non-polar polyolefin and biodegradable polyester systems, respectively. The process sequence of main plasticization followed by side feeding, pre-wetting, dispersion mixing, homogenization and vacuum degassing can all complete continuous masterbatch molding.

[0145] Verification Example 1; Supplementary verification of the molding performance of masterbatch after humidification of seaweed charcoal grinding powder; Based on the masterbatch molding verification given in Example 5, this verification example only conducts supplementary verification of the stability of side feeding after humidification: seaweed charcoal calcined powder prepared in Example 1 is selected, and ordinary pyrolytic seaweed charcoal powder, activated pore-enhancing seaweed charcoal powder and seaweed charcoal powder with equal total return amount and no cross-sectional treatment of the crushing zone are used as controls. Each group of powders is classified by airflow to D 50 The size is 8.5–9.0 μm and D 90After the particle size reaches 24.0–25.5 μm, it is placed in an environment of 25°C and 75% relative humidity for 48 hours, and then verified according to the polypropylene masterbatch process of Example 5A.

[0146] The powder obtained in Example 1, after 48 hours of conditioning, had a moisture content of 0.46%, a side feed rate coefficient of variation of 2.8%, a main engine torque coefficient of variation of 4.8%, a filtration pressure increment of 0.18 MPa over 30 minutes, and an agglomerated particle count of 3.2 particles / 10 mm. 2 Compared to the three control samples, its side feeding fluctuation, filtration pressure difference and number of aggregated particles were all at a lower level.

[0147] This verification example serves only as a further supplement to the masterbatch molding data of Example 5, and will not repeat the same equipment structure, screw assembly, temperature zone and detailed testing steps as in Example 5.

Claims

1. A process for preparing seaweed charcoal powder, characterized in that, Includes the following steps: The seaweed raw material is sorted into any form, such as sheet or granule. Desalination solution is sprayed from the outer surface of the seaweed raw material. The spraying is stopped before the desalination solution reaches the central area of ​​the seaweed raw material. After solid-liquid separation and drying, seaweed carbonization precursor is obtained. The seaweed carbonization precursor is fed into a pyrolysis device, where it undergoes low-temperature devolatilization and high-temperature carbonization in an inert atmosphere to produce hot seaweed char. The pyrolysis gas generated by the pyrolysis is then subjected to dust removal and segmented condensation to collect the high-temperature condensed components. The high-temperature condensed components are processed into either a gasified or atomized state and then returned to the hot seaweed char surface deposition area. After surface deposition and heat preservation carbonization, a carbonized deposition layer is formed on the outer surface of the seaweed char. The seaweed charcoal of the carbonized deposit layer is fed into a pulverizing device under an inert atmosphere in a hot state, and the high-temperature condensed components are processed into either a gasified state or an atomized state before being introduced into the pulverizing zone, where they come into contact with the fresh cross-section of the seaweed charcoal during the pulverizing process. The pulverized seaweed charcoal is fed into a heat-insulating carbonization zone, where it is cooled and classified by particle size to obtain seaweed charcoal powder.

2. The preparation process of seaweed charcoal powder according to claim 1, characterized in that, The seaweed raw material is processed into any form, either sheet material with a thickness of 2-6 mm or granular material with a particle size of 2-6 mm, and the contact time between the desalination solution and the seaweed raw material is 20-90 s.

3. The preparation process of seaweed charcoal powder according to claim 1, characterized in that, The low-temperature devolatilization temperature is 280–360°C, and the high-temperature carbonization temperature is 540–620°C.

4. The preparation process of seaweed charcoal powder according to claim 3, characterized in that, The high-temperature condensing component is taken from the high-temperature condensing section in the segmented condensation process. The wall temperature of the high-temperature condensing section is 150-220°C. The amount of the high-temperature condensing component returned to the seaweed carbon surface deposition area and the crushing area is 3%-8% based on the dry weight of the seaweed carbon after high-temperature carbonization.

5. The preparation process of seaweed charcoal powder according to claim 1, characterized in that, The temperature of the seaweed carbon that forms the carbonized deposit layer when it enters the pulverizing device is 180–300℃.

6. The preparation process of seaweed charcoal powder according to claim 1, characterized in that, The high-temperature condensed components are split into a first stream and a second stream. The first stream is introduced into the surface deposition zone of the hot seaweed charcoal, and the second stream is introduced into the pulverizing zone. The pulverized seaweed charcoal is then sent to the heat-insulating carbonization zone connected to the end of the carbonization section.

7. A method for forming carbon-based masterbatch, characterized in that, The seaweed charcoal powder prepared using the seaweed charcoal grinding process according to any one of claims 1 to 6 is then used to form carbon-based masterbatch. The carbon-based masterbatch forming method includes the following steps: Seaweed charcoal powder is obtained by surface desalination treatment of seaweed raw materials, inert atmosphere pyrolysis treatment, high temperature condensation component return deposition treatment, hot crushing treatment and cross-sectional carbonization treatment, and the high temperature condensation component comes from the pyrolysis gas of the same batch of seaweed raw materials. The polymer carrier resin is added to the barrel of the twin-screw extruder through the main feed port, forming a continuous polymer melt in the main plasticizing section; The seaweed charcoal powder is fed into a continuous polymer melt through a side feed port located downstream of the main plasticizing section, and passes through a pre-wetting section, a dispersion and mixing section and a homogenization section in sequence. The homogenized molten mixture is vacuum degassing, extruded through a die head, cooled, and pelletized to obtain carbon-based masterbatch.

8. The carbon-based masterbatch forming method according to claim 7, characterized in that, After drying, sieving, and metering, the seaweed charcoal powder is added to the cylinder in powder form through the side feed port.

9. The carbon-based masterbatch forming method according to claim 7, characterized in that, The polymer carrier resin is selected from either polypropylene or polylactic acid.

10. The carbon-based masterbatch forming method according to claim 7, characterized in that, The pre-wetting section is equipped with a conveying thread element and a low-shear mixing element, the dispersing and mixing section is equipped with a kneading element, the homogenizing section is equipped with a conveying thread element, and the vacuum exhaust port is located in the downstream barrel section of the homogenizing section.

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