Process for manufacturing bamboo charcoal fiber from biomass material

Abstract

The invention discloses a process for manufacturing bamboo charcoal fibers from a biomass material, and belongs to the technical field of biomass material processing, the process for manufacturing the bamboo charcoal fibers from the biomass material comprises the following steps: S1, pretreatment of bamboo wood: cutting the bamboo wood, soaking the cut bamboo wood in an alkaline solution with the mass fraction of 3-8%, and cooking to remove lignin; s2, pre-carbonization treatment is conducted, specifically, the bamboo wood is subjected to primary carbonization in an inert gas environment; s3, carrying out segmented carbonization-activation, and carrying out gradient heating in two stages under the nitrogen pressure of 0.2-1.2 MPa; and S4, fiber forming: carrying out melt spinning on the activated bamboo charcoal and the bio-based polymer to obtain the fiber. Through segmented gradient carbonization and activation, bio-based polymer blending and environment-friendly process integration, efficient and green preparation of the bamboo charcoal fibers is achieved, the adsorption performance, the mechanical strength and the degradability are remarkably improved, and meanwhile energy consumption and pollution are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass material processing, and particularly relates to a process for manufacturing bamboo charcoal fiber from biomass materials. Background Art

[0002] The preparation process of traditional bamboo charcoal fiber has the following technical bottlenecks: low carbonization efficiency and serious pollution: existing processes mostly adopt single high-temperature carbonization, resulting in high energy consumption, large dosage of activating agent, and high cost of waste liquid treatment; fiber structure defects: the lack of segmented temperature control in the carbonization process leads to uneven distribution of micropores in bamboo charcoal, insufficient adsorption capacity, and difficulty in meeting the requirements of medical protection; poor equipment integration: traditional carbonization furnaces are of fixed structure, unable to flexibly adjust temperature and pressure parameters, and the accuracy of the activating agent injection system is low, affecting the activation uniformity; poor material compatibility: when bamboo charcoal is blended with synthetic polymers, the interfacial bonding force is weak and the fiber is prone to breakage.

[0003] The present invention proposes an innovative solution to the above problems. By combining two-stage temperature control with synchronous injection of phosphoric acid atomized liquid, the microporous structure is optimized. A detachable temperature control module group is adopted to support segmented pressure regulation and precise injection of activating agent. Degradable materials such as polylactic acid (PLA) are selected, and the fiber strength and environmental protection are improved through melt spinning. Summary of the Invention

[0004] The present invention provides a process for manufacturing bamboo charcoal fiber from biomass materials. Through the coordinated action of bamboo material pretreatment, segmented temperature-controlled carbonization-activation, melt spinning of bio-based polymers, and modular equipment, bamboo charcoal fiber with high adsorption and low energy consumption is prepared, which is applicable to the environmental protection and medical fields.

[0005] Technical Solution: A process for manufacturing bamboo charcoal fiber from biomass materials, characterized by comprising the following steps: (1) Bamboo material pretreatment: Cut the bamboo material and soak it in an alkaline solution for cooking treatment; (2) Pre-carbonization treatment: Preliminarily carbonize the pretreated bamboo material in an inert gas environment; (3) Carbonization-activation treatment: Gradually increase the temperature of the pre-carbonized bamboo material for carbonization under segmented temperature control conditions, and simultaneously inject an activating agent; (4) Fiber forming: Mix the carbonized and activated bamboo charcoal material with a bio-based polymer, and prepare fibers through melt spinning.

[0006] Preferably, in step (1), the mass fraction of the alkaline solution is 3-8%, the cooking temperature is 80-120°C, and the time is 1-3 hours.

[0007] Preferably, step (3) includes: a) The first carbonization stage: Raise the temperature to 500-600°C under a nitrogen pressure of 0.2-0.5 MPa and keep it warm for 20-40 minutes; b) The second carbonization stage: Heat up to 800 - 900 °C under a nitrogen pressure of 0.8 - 1.2 MPa, and at the same time inject a phosphoric acid atomized liquid with a mass fraction of 5 - 10%, and keep it warm for 10 - 20 minutes.

[0008] Preferably, the atomized particle size of the phosphoric acid atomized liquid is 10 - 50 μm, and the injection rate is 0.5 - 2 L / min.

[0009] Preferably, in step (4), the bio - based polymer is any one of polylactic acid (PLA), polyhydroxyalkanoate (PHA), and polybutylene succinate (PBS), and the mass ratio of the bamboo charcoal material to the polymer is 1:3 - 1:5.

[0010] Preferably, in step (1), the alkaline solution is any one of aqueous solutions of sodium hydroxide and potassium hydroxide, and the pH value of the solution is controlled between 10 - 13.

[0011] Preferably, the heating rate in the first carbonization stage is 5 - 15 °C / min, and the heating rate in the second carbonization stage is 8 - 20 °C / min.

[0012] Preferably, the activator in step (3) includes at least one of phosphoric acid, potassium carbonate, and zinc chloride, and the mass ratio of the activator to the bamboo is 1:5 - 1:10.

[0013] Preferably, the phosphoric acid atomized liquid is prepared by an ultrasonic atomization device, and the temperature is maintained at 30 - 50 °C and the pressure is 0.3 - 0.6 MPa during the atomization process.

[0014] Preferably, the melt - spinning temperature is 180 - 230 °C, the spinning pressure is 5 - 15 MPa, the fiber after spinning is cooled by a cold water bath, and the draw ratio is 3 - 8 times.

[0015] Compared with the prior art, the advantages of the present invention are as follows: (1) The segmented gradient carbonization and activation technology: Adopt two - stage temperature - controlled carbonization, the first stage is 500 - 600 °C / 0.2 - 0.5 MPa, the second stage is 800 - 900 °C / 0.8 - 1.2 MPa, and atomized activator is injected synchronously; form a hierarchical pore structure, the specific surface area reaches 1000 - 1500 m² / g; the dosage of the activator is reduced by 30%, the carbonization efficiency is increased by 20%, and the energy consumption is reduced by 25%.

[0016] (2) Enhanced adaptability of bio - based polymers: Select PLA / PHA / PBS bio - based materials, the mass ratio of bamboo charcoal to the polymer is 1:3 - 1:5; the tensile strength of the fiber reaches 3.5 - 4.5 cN / dtex; the degradability is significantly improved.

[0017] (3)Environmental protection process integration: nitrogen protection throughout the process, reverse osmosis membrane recovery of alkaline solution; no harmful substance emissions, 60% reduction in wastewater treatment cost; pretreatment to remove lignin and hemicellulose, retaining the cellulose skeleton. Brief Description of the Drawings

[0018] Figure 1 It is a flowchart of a process for manufacturing bamboo charcoal fiber from biomass materials proposed by the present invention. Detailed Implementation Modes

[0019] Example 1: A process for manufacturing bamboo charcoal fiber from biomass materials. First, bamboo is immersed in a 5% NaOH solution with pH = 12, and cooked at 100 °C for 2 hours at a solid-liquid ratio of 1:8 to remove lignin. After washing and drying, pretreated bamboo is obtained and dried at 105 °C for 4 hours; then, under nitrogen protection, it is heated to 300 °C at a rate of 10 °C / min for pre-carbonization treatment and held for 1 hour to form a primary carbon structure; the key carbonization-activation process is divided into two stages: in the first stage, it is heated to 550 °C at a rate of 10 °C / min under a nitrogen pressure of 0.3 MPa and held for 30 minutes, and in the second stage, the pressure is increased to 1.0 MPa and heated to 850 °C at a rate of 15 °C / min, while injecting a 10% phosphoric acid solution atomized by ultrasonic waves with an atomization particle size of 25 μm, a temperature of 40 °C, a pressure of 0.5 MPa, and an injection rate of 1 L / min, and held for 15 minutes to complete the construction of microporous structure, with a mass ratio of activator to bamboo of 1:8; finally, the bamboo charcoal and PLA are mixed at a ratio of 1:4, granulated by a twin-screw extruder at 200 °C, and melt-spun at 210 °C and 10 MPa, quenched by a 15 °C cold water bath and subjected to a 5-fold draw ratio to obtain high-performance bamboo charcoal fiber with a specific surface area of 1250 m² / g and a breaking strength of 4.2 cN / dtex, with a formaldehyde adsorption rate of 92.3% and a far-infrared emissivity of 88.5%.

[0020] Example 2: A process for manufacturing bamboo charcoal fiber from biomass materials. First, bamboo is soaked in a 6% KOH solution with a pH of 12.5 and cooked at 90 °C for 2.5 hours at a solid-liquid ratio of 1:10 to remove lignin. After washing and drying, the pretreated bamboo is obtained and dried at 105 °C for 3 hours. Subsequently, under nitrogen protection, it is heated to 280 °C at a rate of 8 °C / min for pre-carbonization treatment and held for 1.5 hours to form a primary carbon structure. The key carbonization-activation process is divided into two stages: in the first stage, it is heated to 580 °C at a rate of 12 °C / min under a nitrogen pressure of 0.4 MPa and held for 25 minutes; in the second stage, the pressure is increased to 1.1 MPa and it is heated to 880 °C at a rate of 18 °C / min, and an 8% potassium carbonate solution atomized by ultrasonic waves is injected synchronously. The atomization particle size is 30 μm, the temperature is 35 °C, the pressure is 0.6 MPa, and the injection rate is 0.8 L / min. After holding for 12 minutes, the microporous structure is constructed, and the mass ratio of the activator to bamboo is 1:7. Finally, the bamboo charcoal and PHA are mixed at a ratio of 1:5, granulated by a twin-screw extruder at 210 °C, and melt-spun at 220 °C and 12 MPa. It is quenched by a 10 °C cold water bath and stretched by a draw ratio of 6 times to obtain an environmentally friendly bamboo charcoal fiber with an average pore diameter of 3.2 nm and a UPF value of 50+, a soil degradation rate of 45%, and an elongation at break of 12%.

[0021] Example 3: A process for manufacturing bamboo charcoal fiber from biomass materials. First, bamboo is soaked in a 7% NaOH solution with a pH of 13 and cooked at 110 °C for 1.5 hours at a solid-liquid ratio of 1:6 to remove lignin. After washing and drying, the pretreated bamboo is obtained and dried at 105 °C for 2 hours. Subsequently, under nitrogen protection, it is heated to 320 °C at a rate of 15 °C / min for pre-carbonization treatment and held for 0.5 hours to form a primary carbon structure. The key carbonization-activation process is divided into two stages: in the first stage, it is heated to 520 °C at a rate of 5 °C / min under a nitrogen pressure of 0.2 MPa and held for 40 minutes; in the second stage, the pressure is increased to 1.2 MPa and it is heated to 900 °C at a rate of 20 °C / min, and a 5% zinc chloride solution atomized by ultrasonic waves is injected synchronously. The atomization particle size is 15 μm, the temperature is 50 °C, the pressure is 0.3 MPa, and the injection rate is 2 L / min. After holding for 10 minutes, the microporous structure is constructed, and the mass ratio of the activator to bamboo is 1:5. Finally, the bamboo charcoal and PBS are mixed at a ratio of 1:3, granulated by a twin-screw extruder at 180 °C, and melt-spun at 190 °C and 5 MPa. It is quenched by a 20 °C cold water bath and stretched by a draw ratio of 3 times to obtain a functional bamboo charcoal fiber with a conductivity of 8.5×10 -5 S / cm and a thermal conductivity of 0.38 W / (m·K), with a tensile modulus of 1200 MPa and a thermal decomposition temperature of 260 °C.

[0022] Example 4: A process for manufacturing bamboo charcoal fiber from biomass materials. First, bamboo is soaked in a 3% NaOH solution with a pH of 10 and cooked at 120°C for 1 hour under a solid-liquid ratio of 1:12 to remove lignin. After washing and drying, the pretreated bamboo is obtained and dried at 105°C for 5 hours. Subsequently, under nitrogen protection, it is heated to 350°C at a rate of 12°C / min for pre-carbonization treatment and held for 0.8 hours to form a primary carbon structure. The key carbonization-activation process is divided into two stages: in the first stage, it is heated to 600°C at a rate of 15°C / min under a nitrogen pressure of 0.5 MPa and held for 20 minutes; in the second stage, the pressure is increased to 0.8 MPa and it is heated to 900°C at a rate of 20°C / min, and a 10% phosphoric acid solution atomized by ultrasonic waves with an atomization particle size of 50 μm, a temperature of 30°C, a pressure of 0.3 MPa, and an injection rate of 0.5 L / min is injected synchronously. After holding for 10 minutes, the microporous structure is constructed, and the mass ratio of the activator to bamboo is 1:10. Finally, the bamboo charcoal is mixed with a PLA / PHA blend (mass ratio 1:1) in a ratio of 1:3, granulated by a twin-screw extruder at 230°C, and melt-spun at 230°C and 15 MPa. It is quenched by a 5°C cold water bath and stretched with an 8-fold draw ratio to obtain high-performance bamboo charcoal fiber with a specific surface area of 1450 m² / g and a breaking strength of 4.5 cN / dtex, with a formaldehyde adsorption rate of 95% and a microporosity increase of 20%.

[0023] Performance testing Fiber tensile property testing: Verify the improvement effect of segmented carbonization activation and blending with bio-based polymers on the mechanical properties of the fiber, and compare the breaking strength and elongation at break of different examples.

[0024] Take 20 fibers from each of the fiber products of Examples 1-4, with a length of 100 mm. Pretreatment conditions: equilibrate in an environment of 23°C / 50%RH for 24 h; use an electronic universal testing machine under environmental conditions of 23±2°C and a relative humidity of 50±5%, with a gauge length of 50 mm and a tensile rate of 50 mm / min, and execute the test standard ASTM D3822 to obtain the following results: Fiber degradability testing: Verify the improvement of the degradation performance of bamboo charcoal fiber by blending with bio-based polymers, and evaluate the influence of different activation processes on the degradation rate.

[0025] Use the soil burial method ASTM D5988 and the compost degradation method EN 13432 for non-woven fabric samples (each with an area of 5 cm×5 cm and a mass of about 0.5 g) generated by the processes of Examples 1-4. After sterilization, bury them in different media (soil group: standard soil humidity 60%, temperature 25°C, pH 7.0; compost group: industrial compost conditions 58°C, humidity 70%, ventilation). Take samples once every two weeks for 12 consecutive weeks.

[0026] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the descriptions in the specification are only preferred examples of the present invention, which are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for manufacturing bamboo charcoal fibers from biomass materials, characterized in that, It includes the following steps: (1) Bamboo pretreatment: Cut the bamboo and soak it in an alkaline solution for steaming treatment; (2) Pre-carbonization treatment: Preliminarily carbonize the pretreated bamboo in an inert gas environment; (3) Carbonization-activation treatment: Gradually increase the temperature of the pre-carbonized bamboo for carbonization under segmented temperature control conditions, and simultaneously inject an activator; (4) Fiber forming: Mix the carbonized and activated bamboo charcoal material with a biobased polymer and prepare fibers by melt spinning.

2. The process for manufacturing bamboo charcoal fibers from biomass materials according to claim 1, characterized in that, In step (1), the mass fraction of the alkaline solution is 3-8%, the steaming temperature is 80-120 °C, and the time is 1-3 hours.

3. The method according to claim 2, wherein Step (3) includes: a) The first carbonization stage: Heat up to 500-600 °C under a nitrogen pressure of 0.2-0.5 MPa and keep it warm for 20-40 minutes; b) The second carbonization stage: Heat up to 800-900 °C under a nitrogen pressure of 0.8-1.2 MPa, and simultaneously inject a phosphoric acid atomized solution with a mass fraction of 5-10%, and keep it warm for 10-20 minutes.

4. The method according to claim 3, characterized in that, The atomized particle size of the phosphoric acid atomized solution is 10-50 μm, and the injection rate is 0.5-2 L / min.

5. The process for manufacturing bamboo charcoal fiber from biomass materials according to claim 1, characterized in that, In step (4), the biobased polymer is any one of polylactic acid PLA, polyhydroxyalkanoate PHA, and polybutylene succinate PBS, and the mass ratio of the bamboo charcoal material to the polymer is 1:3-1:

5.

6. The process for manufacturing bamboo charcoal fiber from biomass materials according to claim 1, characterized in that, In step (1), the alkaline solution is any one of sodium hydroxide and potassium hydroxide aqueous solutions, and the pH value of the solution is controlled between 10 and 13.

7. The method according to claim 3, wherein The heating rate in the first carbonization stage is 5-15 °C / min, and the heating rate in the second carbonization stage is 8-20 °C / min.

8. A process for manufacturing bamboo charcoal fiber from biomass materials according to claim 1, characterized in that, The activator in step (3) includes at least one of phosphoric acid, potassium carbonate, and zinc chloride, and the mass ratio of the activator to the bamboo is 1:5-1:

10.

9. The method according to claim 4, wherein The phosphoric acid atomized solution is prepared by an ultrasonic atomization device, and the temperature is maintained at 30-50 °C and the pressure is 0.3-0.6 MPa during the atomization process.

10. The method according to claim 5, wherein The melt spinning temperature is 180-230 °C, the spinning pressure is 5-15 MPa, the fibers after spinning are cooled by a cold water bath, and the draw ratio is 3-8 times.

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