Pyrolysis condensate preparation process and treatment method for bamboo products for food contact

Abstract

The invention relates to the technical field of bamboo mould prevention, and particularly discloses a pyrolysis condensate preparation process and a treatment method for bamboo products for food contact, and the pyrolysis condensate preparation process comprises the following steps: (S01) taking a proper amount of pyrolysis condensate raw material, and sequentially crushing, drying and cooling to obtain a constant-weight material; (S02) sieving the constant-weight material in the step (S01), placing the sieved constant-weight material in a pyrolysis condensate preparation mechanism, and sequentially pyrolyzing and condensing the sieved constant-weight material to obtain a crude pyrolysis condensate; and (S03) continuously and sequentially carrying out low-temperature standing and filtering on the crude pyrolysis condensate in the step (S02) in the pyrolysis condensate preparation mechanism to obtain refined pyrolysis condensate. The mildewproof and antibacterial coating has the characteristics of good mildewproof and antibacterial effects and sufficient environmental protection property and safety.

Description

Technical Field

[0001] This invention relates to the field of bamboo anti-mildew technology, and in particular to a process for preparing pyrolysis condensate and a method for treating bamboo products for food contact. Background Technology

[0002] Plastic pollution is increasingly serious among global environmental issues, especially the significant damage to the ecological environment caused by fast-moving consumer goods (FMCG) such as plastic straws. Against this backdrop, bamboo, as a green, renewable, and biodegradable biomass material, has become a high-quality sustainable alternative to plastics. Bamboo FMCG products cover multiple fields, including tableware, packaging, medical supplies, hotel supplies, and daily necessities, demonstrating their potential as an ideal environmentally friendly alternative to plastic FMCG products and possessing a huge domestic and international consumer market. The "Bamboo for Plastic" initiative jointly launched by the Chinese government and the International Bamboo and Rattan Organisation (INBAR) has further promoted the popularization of bamboo products in the international market. Among these, bamboo tableware, as an important component of bamboo FMCG products, emphasizes the importance of developing food-grade bamboo tableware based on its environmental friendliness and safety. Considering its raw material characteristics, usage scenarios, and broad application prospects, promoting the research and application of bamboo tableware is particularly crucial.

[0003] Soaking bamboo tableware in anti-mold and antibacterial agents can improve its anti-mold performance. Currently, the anti-mold and antibacterial agents used on bamboo tableware are mainly chemically synthesized organic compounds, which can all cause certain harm to the human body. Patent document CN112157770A discloses an environmentally friendly method for preventing mold growth in bamboo. The method includes: S1 treating bamboo with ultrasound to remove green and yellowing substances, using an ultrasonic frequency of 50kHz-100kHz, an ultrasonic power of 400-800W, and an ultrasonic temperature of 20-80℃; S2 preparing a compound antifungal agent using sodium acetate and butylparaben, or sodium diacetate and butylparaben, or sodium diacetate and propylparaben; and S3 preparing a compound paraffin emulsion using food-grade paraffin wax (No. 58), 2-hydroxy-1,4-naphthoquinone, Tween 60, and distilled water. This method utilizes the thermal and mechanical effects of ultrasound to break down starch and inclusions in bamboo. Combined with a food-grade antifungal agent and food-grade paraffin, the bamboo treated by this method can not only be used for mold prevention in common daily bamboo products such as bamboo buckets, chopsticks, cutting boards, and toothbrushes, but also significantly improve the dimensional stability, mechanical properties, hardness, wear resistance, and hydrophobicity of bamboo. However, the so-called food-grade anti-mold agent used is still a compound made of sodium acetate and butylparaben, or sodium diacetate and butylparaben, or sodium diacetate and propylparaben. In addition, food-grade paraffin No. 58, 2-hydroxy-1,4-naphthoquinone and Tween 60 are added. Even after the anti-mold treatment of daily bamboo products, it will still be harmful to the human body.

[0004] Therefore, current anti-mold and antibacterial treatments for bamboo products used in food contact have problems such as poor anti-mold and antibacterial effects, and insufficient environmental protection and safety. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems in the existing anti-mold and antibacterial treatment of bamboo products for food contact, the present invention provides a pyrolysis condensate preparation process and a method for treating bamboo products for food contact, which has the characteristics of good anti-mold and antibacterial effect, and sufficient environmental protection and safety.

[0006] The first technical solution of the present invention: a process for preparing pyrolysis condensate, comprising the following steps:

[0007] (S01) Take an appropriate amount of pyrolysis condensate raw material, and after successively crushing, drying and cooling, obtain constant weight material;

[0008] (S02) The constant weight material in step (S01) is sieved and placed in the pyrolysis condensate preparation mechanism for sequential pyrolysis and condensation to obtain crude pyrolysis condensate;

[0009] (S03) The crude pyrolysis condensate from step (S02) is further subjected to low-temperature settling and filtration to obtain refined pyrolysis condensate. The process route of this invention is pretreatment → pyrolysis condensation → refining, with a clear structure and correct logic. It transforms woody biomass into a liquid rich in phenols, carbonyl compounds, and other flavor and antibacterial components through controlled pyrolysis, and removes impurities and harmful substances through the refining step, ultimately obtaining a safe, efficient, and flavor-pure refined pyrolysis condensate suitable for food processing. This invention ensures constant weight of raw materials through crushing, drying, and cooling steps, eliminating moisture interference (bamboo needs to be dried to a moisture content ≤8% to avoid diluting the concentration of the pyrolysis condensate), improving subsequent pyrolysis efficiency, and ensuring product stability. Pretreatment of the raw materials ensures uniform, efficient, and controllable subsequent pyrolysis effects; the crushing process increases the specific surface area, making the raw material particles smaller. The process achieves greater uniformity, resulting in more even heating during pyrolysis, more complete and faster reaction, effectively avoiding localized overheating and carbonization or incomplete dissociation, improving the yield and consistency of the target product, and significantly enhancing pyrolysis efficiency and quality. Drying removes free water and some bound water, preventing excessive vaporization during pyrolysis that consumes large amounts of energy, reducing energy consumption, and avoiding excessive water vapor dilution of pyrolysis products, which could affect condensation efficiency and increase wastewater treatment load. Obtaining "constant weight material" ensures batch-to-batch quality stability. Cooling terminates the drying process, stabilizes the material state, prevents hot material from directly entering the pyrolysis stage leading to uncontrolled temperature rise, and avoids hot material agglomeration, which could affect the uniformity of sieving and feeding. This invention performs sieving and pyrolysis on constant weight material. The pyrolysis condensate directly ensures the basic composition and yield of the pyrolysis condensate. Sieving effectively controls the particle size of the raw materials, removing excessively fine dust (easily carried away by airflow) and excessively large particles (resulting in incomplete pyrolysis), ensuring uniform particle size of the raw materials entering the pyrolyzer. This guarantees the stability of the pyrolysis process and the uniformity of the products. The pyrolysis temperature is precisely controllable, avoiding incomplete pyrolysis or excessive carbonization as in traditional combustion methods, reducing the formation of harmful substances (such as polycyclic aromatic hydrocarbons), and ensuring the full release of natural antibacterial components in the raw material powder. Pyrolysis energy consumption is lower than traditional methods, which can also appropriately reduce production costs. The pyrolysis process converts high-molecular polymers into volatile small molecules, and heating causes bond breaking and recombination in macromolecules such as lignin, cellulose, and hemicellulose. The process involves a series of reactions to generate volatile flue gas rich in hundreds of compounds, including phenols, aldehydes, ketones, and organic acids. A condensation step effectively collects natural antibacterial components, retains key substances for the smoky flavor (such as phenols and carbonyl compounds), and improves the quality of the pyrolysis condensate. The condensation process achieves gas-liquid separation, trapping the target products and rapidly cooling the high-temperature gaseous pyrolysis flue gas below the dew point, allowing the condensable components (i.e., the crude pyrolysis condensate) to liquefy and be recovered, while the non-condensable solids (coke) and gases (CO, CO2, CH4, etc.) are separated. This invention further refines the crude pyrolysis condensate by allowing it to settle at low temperatures to promote impurity precipitation, followed by filtration to remove particulate matter and condensation residues, resulting in a clear and stable refined pyrolysis condensate.Low-temperature settling effectively achieves sedimentation and separation. Firstly, it removes tar; at low temperatures (typically 0-4℃), high-boiling-point, large-molecule heavy tar, waxes, and other impurities coagulate and precipitate due to decreased solubility and increased viscosity. Secondly, it removes water; some water separates due to density differences, facilitating separation. Thirdly, aging allows some unstable components to react, resulting in a smoother flavor. Filtration removes solid impurities, thoroughly removing tar, carbon residue, and other solid particles that precipitate after low-temperature settling, yielding a clear, transparent, refined pyrolysis condensate. This prevents impurities from clogging equipment or affecting product appearance in subsequent applications, significantly improving product purity and applicability. The entire raw material process... This invention utilizes refined pyrolysis condensate with minimal waste; the refined pyrolysis condensate has fewer impurities, ensuring the safety of the final product and meeting food safety and compliance requirements. The refined pyrolysis condensate used in this invention treats bamboo products, reducing the risk of microbial contamination and imparting natural antibacterial properties, resulting in excellent safety and hygiene. After penetrating the bamboo, the pyrolysis condensate creates a uniform smoky flavor and attractive color, enhancing the bamboo's flavor, improving its color, and increasing product added value. The entire process is flameless, reducing smoke pollution from traditional smoking methods, meeting safety standards for food contact materials, and demonstrating excellent environmental friendliness.

[0010] Preferably, the raw material for the pyrolysis condensate in step (S01) is pine powder, rosewood powder, ebony powder, bamboo chips, eucalyptus powder, or coconut shell powder. The raw material for the pyrolysis condensate can be flexibly selected according to actual needs. Pine powder produces a traditional smoky flavor with a high phenolic content and a rich, strong smoky aroma; rosewood powder produces a unique, possibly sweet and floral, complex flavor; ebony powder produces a very rich, deep, and even chocolate or coffee-like smoky aroma, and is rich in flavor compounds after pyrolysis; bamboo chips reflect the fragrance of bamboo, conforming to the environmental protection concept of "treating bamboo with bamboo," with high resource utilization, consistency between raw materials and application targets, and good component compatibility, resulting in good resource utilization; the eucalyptus oil component in eucalyptus powder brings a unique camphor and herbal flavor, and may have stronger antibacterial properties; coconut shell powder produces a unique caramel and nutty roasted aroma and has high safety. It is important to note that when using rosewood powder as the raw material for preparing pyrolysis condensate, the rosewood powder is rich in phenolic compounds (eugenol, guaiacol), aldehydes and ketones (4-ethyl-2-methoxyphenol), and organic acids (acetic acid, propionic acid). Through pyrolysis, natural antibacterial components are released, and the resulting pyrolysis condensate can disrupt the integrity of microbial cell membranes, interfere with the activity of mold metabolic enzymes, lower the pH value of bamboo surface, and inhibit mold spore germination. Rosewood powder is also dense and rich in aromatic compounds, which can enhance the aroma quality and flavor profile of the pyrolysis condensate.

[0011] Preferably, the pyrolysis condensate raw material in step (S01) is free from mold and dust. Using mold-free raw materials avoids the introduction of toxins (such as aflatoxin) or microbial contamination from moldy raw materials, ensuring that the pyrolysis condensate meets the hygiene standards for food contact materials and guaranteeing the safety of the raw materials. Using dust-free raw materials reduces impurities and prevents the generation of burnt flavors or harmful byproducts during subsequent pyrolysis, ensuring the purity of the final refined pyrolysis condensate. High-quality raw materials ensure that the pyrolysis condensate has a pure aroma, is free of off-flavors, and guarantees flavor stability.

[0012] Preferably, the pulverization in step (S01) is carried out in a pulverizer. Mechanical pulverization makes the wood flour particle size uniform, improves the efficiency of subsequent drying and pyrolysis, and avoids local overheating or incomplete dissociation; the pulverizer can be an FS-200 universal pulverizer, a WF-30B universal pulverizer, or a QLM-10K air jet mill.

[0013] Preferably, the drying in step (S01) is carried out in a forced-air drying oven. The forced convection within the oven accelerates moisture evaporation, shortens drying time, avoids uneven drying caused by natural drying, and prevents localized moisture residue or over-drying. The forced-air drying oven can be selected from DHG-9070A (Shanghai Yiheng Scientific Instruments), BINDERED-115 (Bindered, Germany), GYW-300 (Nanjing Huanke Testing Equipment), or MemmertUF-260 (Memmert, Germany).

[0014] Preferably, the drying temperature in step (S01) is 100°C to 110°C. More preferably, the drying temperature in step (S01) is 102°C to 108°C. Even more preferably, the drying temperature in step (S01) is 105°C. The defined drying temperature ensures sufficient evaporation of moisture while avoiding excessively high temperatures that could lead to the loss of volatile flavor compounds, achieving an optimal balance between drying speed and component retention, and reducing energy waste.

[0015] Preferably, the cooling in step (S01) is water cooling. Water cooling is more efficient than natural cooling, preventing residual heat from causing the raw materials to continue to lose water or oxidize.

[0016] Preferably, the drying and cooling in step (S01) are performed in a cycle. The cyclical operation gradually approaches constant weight, avoiding over- or under-drying in a single cycle and achieving precise humidity control; staged drying also reduces energy consumption from continuous high temperatures.

[0017] Preferably, the initial drying time is 4-6 hours, the initial cooling time is 0.4-0.6 hours, the secondary drying time is 0.9-1.1 hours, and the secondary cooling time is 0.4-0.6 hours. More preferably, the initial drying time is 4.5-5.5 hours, the initial cooling time is 0.45-0.55 hours, the secondary drying time is 0.95-1.05 hours, and the secondary cooling time is 0.45-0.55 hours. Even more preferably, the initial drying time is 5 hours, the initial cooling time is 0.5 hours, the secondary drying time is 1 hour, and the secondary cooling time is 0.5 hours. The limited initial drying time effectively removes most of the free water and some of the bound water, establishing a constant weight. The limited initial cooling time quickly stabilizes the raw material temperature, preparing for secondary drying. The limited secondary drying time specifically removes residual moisture, preventing re-moistening. The limited secondary cooling time ensures the material temperature is suitable for subsequent sieving or pyrolysis.

[0018] Preferably, constant weight material is obtained when the mass difference between two consecutive drying and cooling cycles does not exceed 1g. A mass difference of ≤1g between adjacent cycles ensures extremely low moisture content in the raw materials, improves the consistency of pyrolysis products, and reduces batch-to-batch variations in pyrolysis condensate. This invention significantly reduces human error through parameter refinement (such as temperature and time gradients) and cyclic operation, making it suitable for large-scale production and ensuring process stability. The constant weight standard (≤1g deviation) ensures stable flavor, color, and functional component (such as phenol) content in each batch of pyrolysis condensate, guaranteeing product consistency. Controllable conditions throughout the process avoid contamination risks, meet food-grade processing requirements, and ensure food safety. The use of temperature control and cyclic cooling optimizes efficiency and quality, making it particularly suitable for the preparation of high-value-added food contact materials.

[0019] Preferably, the sieving in step (S02) is through an 18-22 mesh sieve; or through a 19-21 mesh sieve. More preferably, the sieving in step (S02) is through a 20 mesh sieve. This specific sieve size ensures uniform wood flour particle size, preventing excessively fine powder from causing rapid pyrolysis (easy carbonization) or excessively coarse particles from incomplete pyrolysis. Uniform particle size also ensures uniform heat transfer during pyrolysis, preventing localized overheating and the generation of harmful substances such as polycyclic aromatic hydrocarbons (PAHs).

[0020] Preferably, the heating source in the pyrolysis process of step (S02) is a temperature-controlled electric heating rod. The temperature-controlled electric heating rod has a fast response speed and, when used with a PID controller, can achieve an accuracy of ±1℃, enabling precise temperature control; it produces no open flame, reducing the risk of combustion and meeting the requirements of a food-grade production environment. The model of the temperature-controlled electric heating rod can be HTS-1000 (Jiangsu Henglite), OMEGACSH-2424 (Omega, USA), DYZ-6K (Shanghai Dongyue), or WATTCOVHZ series (Wattco, USA).

[0021] Preferably, the voltage during the pyrolysis process in step (S02) is 220V. This is compatible with industrial standard voltages, eliminating the need for additional transformer equipment and reducing energy costs.

[0022] Preferably, temperature monitoring during the pyrolysis process in step (S02) is performed using a thermocouple thermometer. Thermocouple thermometers are heat-resistant (0–1300℃), provide accurate data, offer real-time feedback, and can be linked to the temperature control system for automatic adjustment. The thermocouple thermometer can be either OMEGAKMQSS-125G-12 (Type K) or Shanghai Automation Instrumentation Factory No. 3 WRKK-131 (Type K).

[0023] Preferably, the pyrolysis endpoint is reached when no more condensate drips in step (S02). This allows for a visual assessment of complete pyrolysis and avoids over-pyrolysis that could lead to the decomposition of active ingredients (phenols, aldehydes).

[0024] Preferably, the pyrolysis temperature in step (S02) is 250℃ to 460℃. More preferably, the pyrolysis temperature in step (S02) is 270℃ to 440℃. More preferably, the pyrolysis temperature in step (S02) is 290℃ to 420℃. More preferably, the pyrolysis temperature in step (S02) is 300℃ to 400℃. More preferably, the pyrolysis temperature in step (S02) is 320℃ to 380℃. More preferably, the pyrolysis temperature in step (S02) is 340℃ to 360℃. Preferably, the pyrolysis temperature in step (S02) is 350℃. The defined pyrolysis temperature covers the pyrolysis range of lignin and cellulose; at this temperature, the yields of phenols (such as guaiacol and eugenol) and carbonyl compounds (key to smoky aroma) are highest, which will maximize flavor compounds; it can impart uniform smoky color and antibacterial properties to bamboo.

[0025] Preferably, the pyrolysis time in step (S02) is 30 min to 105 min. More preferably, the pyrolysis time in step (S02) is 35 min to 100 min. More preferably, the pyrolysis time in step (S02) is 40 min to 95 min. More preferably, the pyrolysis time in step (S02) is 45 min to 90 min. More preferably, the pyrolysis time in step (S02) is 50 min to 85 min. More preferably, the pyrolysis time in step (S02) is 55 min to 80 min. More preferably, the pyrolysis time in step (S02) is 60 min to 75 min. More preferably, the pyrolysis time in step (S02) is 65 min to 70 min. A limited pyrolysis time ensures that different components are fully pyrolyzed (hemicellulose, cellulose, and lignin decompose at different times); it guarantees complete pyrolysis while avoiding prolonged high temperatures that could lead to the oxidation and loss of flavor compounds; too short a time may result in residual undissociated lignin; too long a time increases energy consumption and does not contribute to product improvement.

[0026] Preferably, the heating rate during the pyrolysis process in step (S02) is 5°C / min to 10°C / min. More preferably, the heating rate during the pyrolysis process in step (S02) is 6°C / min to 9°C / min. The heating rate during the pyrolysis process in step (S02) is 7°C / min to 8°C / min. This avoids rapid heating (>15°C / min) leading to localized carbonization, or excessively slow heating (<3°C / min) prolonging the process cycle, thus achieving controllable pyrolysis.

[0027] Preferably, the condensation container in step (S02) is a cooling jacket. The jacket design (with a jacket through which coolant flows) captures volatile components faster than natural condensation, reducing aroma loss; high-temperature steam rapidly liquefies upon cooling, achieving efficient gas-liquid separation and preventing heavy components (tar) from mixing into the refined pyrolysis condensate. The pyrolysis condensate is clear and bright in color, with a rich flavor and lower levels of harmful substances (PAHs) than traditional smoking methods; precise temperature control, time, and particle size management ensure that the physicochemical properties (pH, phenol content) of different batches of pyrolysis condensate deviate by ≤5%; the fully electronic control system avoids the risk of flammable gases and complies with food contact material production standards.

[0028] Preferably, the low-temperature settling temperature in step (S03) is -6°C to -2°C. More preferably, the low-temperature settling temperature in step (S03) is -5°C to -3°C. Preferably, the low-temperature settling temperature in step (S03) is -4°C. At the defined low-temperature settling temperature, high-melting-point impurities (such as some waxes and large-molecule tar) in the pyrolysis condensate will crystallize and precipitate, while effective flavor substances (phenols and carbonyl compounds) remain in a dissolved state; this balances separation efficiency and energy consumption, avoiding co-precipitation of some flavor components due to excessively low temperatures (e.g., <-6°C) or incomplete removal of impurities due to excessively high temperatures (e.g., >-2°C).

[0029] Preferably, the low-temperature settling time in step (S03) is 12h to 36h. More preferably, the low-temperature settling time in step (S03) is 14h to 34h. More preferably, the low-temperature settling time in step (S03) is 16h to 32h. More preferably, the low-temperature settling time in step (S03) is 18h to 30h. More preferably, the low-temperature settling time in step (S03) is 20h to 28h. More preferably, the low-temperature settling time in step (S03) is 22h to 26h. More preferably, the low-temperature settling time in step (S03) is 23h to 25h. More preferably, the low-temperature settling time in step (S03) is 24h. The limited low-temperature settling time covers the time required for most impurities to crystallize and settle, but less than 12 hours may result in incomplete settling, while more than 36 hours will lead to diminishing marginal benefits; ensure that >95% of precipitable impurities precipitate, while avoiding excessively extending the production cycle.

[0030] Preferably, the filtration in step (S03) is disc filtration. The disc can be a diatomaceous earth disc or a sintered stainless steel disc, whose microporous structure (typically 5μm to 10μm) effectively intercepts solid particles precipitated at low temperatures while allowing liquid flavor components to pass through, achieving high-efficiency retention. Compared to filter bags or centrifugal filtration, discs are easier to disassemble and clean, making them suitable for continuous production; they also have a long lifespan (can be repeatedly cleaned and reused), and their consumable costs are lower than those of membrane filtration.

[0031] Preferably, the benzo[a]pyrene content in the purified pyrolysis condensate in step (S03) is detected and controlled to be below 5 μg·kg⁻¹. -1 By removing tar particles adsorbed by benzo[a]pyrene (BaP) through low-temperature settling, and then filtering out residual particles through a filter plate, the content of the potent carcinogen benzo[a]pyrene (BaP) in the refined pyrolysis condensate is strictly limited to meet food safety standards; the benzo[a]pyrene content is endogenously controlled to be below 5 μg·kg throughout the entire process. -1 No additional processing is required.

[0032] Preferably, the total phenol content in the refined pyrolysis condensate of step (S03) is detected and controlled to be between 2 g / L and 5 g / L. More preferably, the total phenol content in the refined pyrolysis condensate of step (S03) is detected and controlled to be between 3 g / L and 4 g / L. Controlling the total phenol content (such as guaiacol and eugenol) within this range ensures sufficient smoky flavor and antibacterial properties; detection ensures that the total phenol content in each batch remains stable within the defined range, avoiding insufficient flavor due to fluctuations in pyrolysis temperature or settling conditions; and by detecting the range of total phenol content in the refined pyrolysis condensate, adjustment parameters are fed back to ensure consistent flavor throughout the entire process.

[0033] Preferably, the carbonyl compound content in the refined pyrolysis condensate of step (S03) is detected and controlled to be between 1 g / L and 3 g / L. More preferably, the carbonyl compound content in the refined pyrolysis condensate of step (S03) is detected and controlled to be between 2 g / L. Controlling the carbonyl compound (e.g., furfural, 5-methylfurfural) content within this range ensures the sweet and roasted aroma of the pyrolysis condensate, guarantees the stability of the entire pyrolysis process, and avoids over-pyrolysis. By detecting the range of carbonyl compound content in the refined pyrolysis condensate, feedback adjustment parameters are provided to ensure the flavor consistency of the refined pyrolysis condensate obtained throughout the entire process.

[0034] The second technical solution of this invention is a method for treating food-contact bamboo with pyrolysis condensate. This method involves taking food-contact bamboo and treating it with pyrolysis condensate through immersion, spraying, coating, or fumigation. This invention provides four treatment methods for food-contact bamboo, which can be flexibly selected according to actual needs. All methods can impart the effective components (phenols, carbonyl compounds, etc.) from the pyrolysis condensate into the food-contact bamboo, achieving antibacterial and antifungal effects, imparting a smoky flavor, and improving color. The treatment methods are simple and diverse; the four methods cover different application scenarios, including deep treatment, surface treatment, complex structure treatment, and manual treatment, forming an effective protective network.

[0035] Preferably, the impregnation process is as follows:

[0036] (a01) Dry food contact bamboo to a moisture content of less than 12%;

[0037] (a02) The pyrolysis condensate is diluted with a solvent to obtain an impregnation working solution with a volume fraction of 10% to 15%; more preferably, an impregnation working solution with a volume fraction of 11% to 14% is obtained; even more preferably, an impregnation working solution with a volume fraction of 12% to 13% is obtained.

[0038] (a03) Completely immerse the dried bamboo material from step (a01) in the impregnation solution from step (a02);

[0039] (a04) Take out the bamboo material after impregnation in step (a03), drain the surface liquid, and dry it at 55°C to 65°C until constant weight; more preferably, dry it at 60°C until constant weight. The impregnation method allows the components of the pyrolysis condensate to deeply penetrate the bamboo. First, the bamboo is dried to a moisture content of <12%, reducing internal moisture and creating space for the pyrolysis condensate to penetrate, avoiding dilution of the active ingredients and significantly improving penetration efficiency and adsorption capacity, effectively solving penetration barriers. The pyrolysis condensate is then diluted with a solvent to a 10%–15% concentration impregnation working solution, balancing effectiveness and safety. This limited concentration range provides sufficient antibacterial components and flavor substances while avoiding excessive residue on the bamboo surface, strong odor, and increased risk of harmful substances (such as benzo[a]pyrene) migration due to excessively high concentrations. Too low a concentration results in insufficient effect, while too high a concentration increases risk and cost. Forced-air drying fully evaporates and removes solvents and some volatile substances from the bamboo surface and shallow layers, reducing residue. Heat treatment also allows some components to bind with the bamboo fibers, fixing the treatment effect and making it more durable. The limited drying temperature ensures effective drying without causing the bamboo to crack.

[0040] Bamboo products are impregnated in an impregnation working solution. The pyrolysis condensate penetrates through the bamboo fiber ducts (to a depth of 200μm–500μm), forming an antibacterial film layer within the pores. The lignin-pyrolysis condensate complex enhances the hydrophobicity of the bamboo, reducing moisture absorption (a 45% decrease in moisture absorption at 60% humidity), thereby reducing bacterial growth. The impregnation method allows the pyrolysis condensate (containing active ingredients such as phenols and carbonyl compounds) to uniformly penetrate the bamboo pores through capillary action, increasing the bamboo fiber porosity by 35%. Compared to surface spraying or fumigation, this method imparts a deeper antibacterial effect and smoky flavor to the bamboo. By adjusting the pyrolysis condensate fraction and the ratio of bamboo to impregnation material... The material-to-liquid ratio, soaking time, and soaking temperature of the soaking solution can precisely control the amount of smoke components adsorbed by the bamboo, avoiding excessive residue or insufficient treatment. The controlled volume fraction of the pyrolysis condensate ensures sufficient antibacterial effect on the bamboo; low concentrations (<10%) may lead to insufficient antibacterial effect, while high concentrations (>15%) may result in excessive benzo[a]pyrene residue on the bamboo. A balance between permeability and component retention rate is crucial. The volume fraction of the pyrolysis condensate can be obtained by compounding refined pyrolysis condensate with a food-grade ethanol aqueous solution. The concentration of the food-grade ethanol aqueous solution is 50%–70% ethanol (v / v), which effectively dissolves the pyrolysis condensate. The non-polar flavor compounds, such as phenols (e.g., guaiacol) and carbonyl compounds, in bamboo have a solubility 3-5 times higher than pure water. Food-grade ethanol aqueous solution can reduce the surface tension of bamboo, increasing the penetration depth of the pyrolysis condensate by 35% (compared to pure water). The residual ethanol has a volatilization rate >99.9% after bamboo drying. The food-grade ethanol aqueous solution itself has bactericidal properties, and in synergy with the phenols in the pyrolysis condensate, it can increase the kill rate of mold on the bamboo surface (e.g., Aspergillus niger) to 99%. Limiting the ratio of bamboo to the working solution ensures complete immersion of the bamboo, avoiding untreated areas. The limited immersion time ensures sufficient penetration of the bamboo and uniform distribution of antibacterial components. The soaking time is crucial; too short a time (<4 hours) will result in insufficient penetration, while too long a time (>8 hours) may damage the bamboo structure. A controlled soaking temperature ensures stable penetration of the pyrolysis condensate into the bamboo. Compared to traditional chemical methods, bamboo products treated with the pyrolysis condensate exhibit broad-spectrum antifungal and antibacterial properties, providing a wider antibacterial spectrum. As a natural pyrolysis condensate, it leaves no chemical residue and possesses excellent antibacterial performance. The soaking method allows for deep penetration with good uniformity and longer-lasting effects. The bamboo acquires a smoky aroma, enhancing product value. Furthermore, it is environmentally friendly, achieving 100% biodegradability and being non-toxic to the environment.

[0041] Preferably, the solvent in step (a02) is one of water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol. The solvent can be flexibly selected according to actual needs; water is the safest and most economical solvent, ethanol has the best permeability, and propylene glycol has a high boiling point, making it suitable for higher-temperature processing.

[0042] Preferably, in step (a03), the ratio of bamboo to impregnation solution is controlled to be 1:3 to 1:5. More preferably, in step (a03), the ratio of bamboo to impregnation solution is controlled to be 1:4. This defined ratio ensures complete immersion and stable concentration, sufficient liquid volume ensures that all parts of the bamboo are treated, and maintains a relatively stable concentration of the working solution during impregnation, thus guaranteeing uniform treatment.

[0043] Preferably, the impregnation temperature in step (a03) is 30°C to 45°C. More preferably, the impregnation temperature in step (a03) is 35°C to 40°C. This defined impregnation temperature accelerates molecular motion and optimizes penetration. Appropriate heating can reduce the viscosity of the working fluid and increase molecular kinetic energy, thereby significantly shortening the time required to reach the ideal penetration depth. This temperature range is far below the point of severe water evaporation and significant component volatilization, achieving an optimal balance between efficiency and energy consumption.

[0044] Preferably, the impregnation time in step (a03) is 4 to 8 hours. More preferably, the impregnation time in step (a03) is 5 to 7 hours. Even more preferably, the impregnation time in step (a03) is 6 hours. The limited impregnation time ensures sufficient penetration and action. Bamboo has a dense structure, requiring sufficient time for the active ingredients to diffuse into the interior through capillary action. The upper limit of 6 hours is determined based on a combination of factors such as concentration, temperature, and bamboo thickness, representing the time required to reach the penetration saturation threshold. Too short a time will result in insufficient penetration, while too long a time will lead to low production efficiency.

[0045] Preferably, the spray treatment is as follows:

[0046] (b01) The pyrolysis condensate is diluted with a solvent to obtain a spray liquid with a volume fraction of 10% to 15%; more preferably, a spray liquid with a volume fraction of 11% to 14% is obtained; a spray liquid with a volume fraction of 12% to 13% is obtained.

[0047] (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the surface of the bamboo material under a pressure of 0.2 MPa to 0.5 MPa; more preferably, under a pressure of 0.3 MPa to 0.4 MPa.

[0048] (b03) The bamboo material sprayed in step (b02) is initially dried at 40°C to 50°C for 5 min to 15 min; more preferably, it is initially dried at 45°C for 10 min.

[0049] (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) 2 to 4 times; more preferably, repeat the process 3 times. Spraying is suitable for surface treatment or large bamboo products that are not easily soaked. The limited spray concentration controls the effective ingredient loading; since it's a surface treatment, the concentration can be considered a "dosage" per unit area. A limited pressure range ensures good atomization, atomizing the liquid into fine droplets, increasing the contact area, and making it easier for the droplets to adhere and spread on the bamboo surface, avoiding uneven flow and guaranteeing good atomization. Preliminary drying prevents droplet aggregation and flow, quickly curing and setting the current coating before the next spray, avoiding mutual dissolution and flow between multiple layers, resulting in uneven distribution and ensuring the uniformity and layering of the coating. A limited number of repetitions allows for the accumulation of functional coatings. A single spray creates a very thin film with insufficient effective ingredient content; through a "spray-dry" cycle, a sufficiently thick effective layer is gradually built, avoiding problems such as flow, slow drying, and high internal stress caused by a single thick coat.

[0050] Preferably, in step (b02), the amount of bamboo material sprayed per unit area is 20 g / m². 2 ~50g / m 2 More preferably, in step (b02), the amount of material sprayed onto the bamboo surface per unit area is 25 g / m². 2 ~45g / m 2 More preferably, in step (b02), the amount of material sprayed onto the bamboo surface per unit area is 30 g / m². 2 ~40g / m 2 More preferably, in step (b02), the amount of material sprayed onto the bamboo surface per unit area is 35 g / m². 2 The limited amount of sprayed fabric allows for precise control of the amount used per unit area, ensuring that a sufficient, non-dripping liquid film is formed on the surface, thus guaranteeing the reproducibility of the effect.

[0051] Preferably, the application method is as follows:

[0052] (c01) The pyrolysis condensate is diluted with a solvent to obtain a coating solution with a volume fraction of 10% to 15%; more preferably, a coating solution with a volume fraction of 11% to 14% is obtained; a coating solution with a volume fraction of 12% to 13% is obtained.

[0053] (c02) Apply the pyrolysis condensate stock solution or the application solution from step (c01) to the surface of the bamboo using an application tool;

[0054] (c03) Curing the bamboo material coated in step (c02) at 50℃~60℃ for 1h~2h; more preferably, curing at 55℃ for 1.5h. The coating method is suitable for small-batch, localized treatment or simple processes, and is highly flexible; the limited curing temperature and time can better achieve the fixing effect, remove residues, and promote the bonding of components.

[0055] Preferably, the amount of material coated per unit area on the bamboo surface in step (c02) is 35 g / m². 2 ~75g / m 2 More preferably, in step (c02), the amount of material coated per unit area on the bamboo surface is 40 g / m². 2 ~70g / m 2 More preferably, in step (c02), the amount of material coated per unit area on the bamboo surface is 45 g / m². 2 ~65g / m 2 More preferably, in step (c02), the amount of material coated per unit area on the bamboo surface is 50 g / m². 2 ~60g / m 2 More preferably, in step (c02), the amount of material coated per unit area on the bamboo surface is 55 g / m². 2 The limited application amount allows for approximate quantification under manual control, providing operators with a clear reference standard for dosage, minimizing human error, and ensuring consistent results.

[0056] Preferably, the application tool in step (c02) is a brush, roller, or scraper. The specific application tool can be flexibly selected according to actual needs, providing operational flexibility. Brushes are suitable for complex shapes, rollers are suitable for large flat surfaces, and scrapers are suitable for controlling extremely thin coatings.

[0057] Preferably, the fumigation method is as follows:

[0058] (d01) Place the bamboo in a sealed fumigation chamber and heat it to make the pyrolysis condensate in the sealed fumigation chamber evaporate.

[0059] (d02) After fumigation is completed, the sealed fumigation chamber from step (d01) is forcibly ventilated and the bamboo is removed. The fumigation method uses vapor deposition, which can handle complex structures and leaves no liquid residue.

[0060] Preferably, the heating temperature in step (d01) is 50°C to 70°C. More preferably, the heating temperature in step (d01) is 55°C to 65°C. Even more preferably, the heating temperature in step (d01) is 60°C. The defined heating temperature promotes effective volatilization of the pyrolysis condensate, and the defined temperature range allows for the effective vaporization of volatile flavors and antibacterial components (phenols, carbonyl compounds) in the pyrolysis condensate, filling the fumigation chamber, while avoiding excessively high temperatures that could lead to component decomposition or increased generation of harmful substances.

[0061] Preferably, the concentration of the pyrolysis condensate vapor in the sealed fumigation chamber of step (d01) is 5 mg / L to 20 mg / L. More preferably, the concentration of the pyrolysis condensate vapor in the sealed fumigation chamber of step (d01) is 10 mg / L to 15 mg / L. This defined vapor concentration range allows for control of the gas phase treatment intensity, ensuring sufficient deposition of effective components onto the bamboo surface per unit time. Too low a concentration is ineffective, while too high a concentration is uneconomical and may increase risks.

[0062] Preferably, the fumigation time in step (d01) is 2h to 6h. More preferably, the fumigation time in step (d01) is 3h to 5h. Even more preferably, the fumigation time in step (d01) is 4h. The limited fumigation time ensures gas phase adsorption equilibrium, requiring sufficient time for vaporized molecules to diffuse, adsorb, and penetrate into the micropores on the bamboo surface to achieve adsorption dynamic equilibrium.

[0063] Preferably, the bamboo material is at least one of bamboo tubes, bamboo strips, bamboo veneer, or bamboo fiber. It is suitable for three-dimensional products such as tableware and cutting boards, as the impregnation solution can penetrate into the interior of the bamboo material; it can enhance the antibacterial properties of the fibers, making it suitable for composite food packaging paper; it has good processing flexibility, allowing different forms of bamboo to be combined for processing, thus improving production efficiency.

[0064] As a preferred method, the content of Aspergillus niger, Trichoderma, and Penicillium on the surface of bamboo after fumigation treatment is detected, and the mold content on the bamboo surface is controlled to be ≤100 CFU / cm³. 2 The phenols (such as guaiacol) in the pyrolysis condensate can inhibit mold growth, ensuring that the mold content on the surface of the treated bamboo meets the standards for food contact materials, thus guaranteeing food safety. Specifically, the inhibition zone diameter against Aspergillus niger is 18.5±0.8mm, and the inhibition rate against Aspergillus niger reaches 99.2%. After 7 days of incubation, the mycelial growth of Trichoderma decreased by 99.1%. Under an environment of 28℃ / RH85%, the spore germination inhibition rate against Penicillium reaches 98.3%. It exhibits good anti-mold durability, maintaining over 85% of its anti-mold performance even after 50 washes. Even after UV + damp heat cycling treatment, the product's shelf life remains ≥18 months.

[0065] The third technical solution of the present invention: an integrated device for preparing pyrolysis condensate and treating bamboo products for food contact, including an oscillation adjustment mechanism, wherein the oscillation end of the oscillation adjustment mechanism is provided with a clamping adjustment mechanism, and an impregnation mechanism is provided below the clamping adjustment mechanism. The clamping adjustment mechanism is adjusted in height relative to the interior of the impregnation mechanism, and the impregnation mechanism is connected to the pyrolysis condensate preparation mechanism through a guide tube. This invention enables "on-demand" production of pyrolysis condensate from raw wood flour. Fresh pyrolysis condensate is directly transported to the impregnation unit via a guide pipe for dilution and preparation, avoiding oxidation loss of active ingredients (phenols, carbonyl compounds) during storage and increasing flavor retention by over 30%. The pyrolysis preparation and impregnation temperatures are linked for optimal active ingredient transfer gradients between the pyrolysis temperature (250℃~460℃) of the pyrolysis condensate preparation unit and the impregnation temperature (30℃~45℃) of the impregnation unit. Furthermore, the invention incorporates an oscillation adjustment mechanism, using controllable mechanical vibration to induce vibration in the bamboo product during impregnation. This disrupts the surface tension of the bamboo, accelerating the penetration of the pyrolysis condensate into the bamboo fiber pores. The penetration depth of the pyrolysis condensate is increased to 80% of the bamboo thickness (compared to only 50% in traditional static impregnation). The invention avoids local concentration gradients caused by static impregnation through vibration, ensuring uniform distribution of antibacterial components (phenols) and flavor substances (carbonyl compounds). By setting up a clamping adjustment mechanism, the invention achieves three-dimensional positioning; the adjustable clamp is compatible with different shapes of bamboo tubes and strips, ensuring stable clamping of bamboo products (bamboo tubes / strips / fibers) in a vibrating environment. By setting up an impregnation mechanism, bamboo products are impregnated in the pyrolysis condensate within the impregnation mechanism, forming an antibacterial film layer within the pores of the bamboo product, reducing moisture adsorption, thereby reducing bacterial growth and fully imparting antibacterial properties and smoky flavor to the bamboo. Through a pyrolysis condensate preparation mechanism, the invention achieves efficient, safe, and controllable conversion of the pyrolysis condensate from raw materials to finished products through a closed-loop technology of "precise pyrolysis - instantaneous condensation - intelligent control."

[0066] Preferably, the oscillation adjustment mechanism includes a support frame, with a pneumatic cylinder at the end of the support frame away from the impregnation mechanism. A hollow mounting box is provided at the piston end of the pneumatic cylinder, and the end of the hollow mounting box away from the pneumatic cylinder is open. A sliding rod is provided inside the hollow mounting box, and a sliding slider is slidably mounted on the sliding rod. The clamping adjustment mechanism is mounted on the sliding slider. A centrifugal motor is provided on the hollow mounting box, with a centrifugal cam at the drive end of the centrifugal motor. A swing shaft is provided at the cam of the centrifugal cam, and a swing connecting rod is rotatably mounted on the swing shaft. A connecting rod is rotatably mounted at the end of the swing connecting rod away from the centrifugal motor, and the connecting rod is connected to the sliding slider. The pneumatic cylinder pushes the hollow mounting box to achieve vertical displacement with an accuracy of ±0.1mm, and the impregnation depth can be adjusted according to the bamboo thickness (e.g., 1mm to 10mm). A segmented impregnation method can be used (e.g., first shallowly impregnate 1 / 3 of the thickness, then fully impregnate), which significantly increases the adsorption capacity of the pyrolysis condensate. A centrifugal motor drives a centrifugal cam, converting the rotational motion into horizontal reciprocating movement of a sliding slider on a sliding rod via a swing shaft and swing linkage. This achieves reciprocating vibration of the clamping and adjusting mechanism within the impregnation mechanism (frequency adjustable from 20Hz to 50Hz), accelerating the penetration of the pyrolysis condensate into the bamboo fiber pores (increasing bamboo fiber pore permeability by 35%), better ensuring the uniform distribution of antibacterial components (phenols) and flavor substances (carbonyl compounds). The mechanical linkage transmission efficiency reaches 92%, which is more energy-efficient than electromagnetic vibrators. The horizontal reciprocating movement of the sliding slider on the sliding rod maintains an amplitude error of <±5μm during vibration, avoiding uneven processing caused by bamboo displacement.

[0067] Preferably, the clamping and adjusting mechanism includes a hollow box, which is disposed at the oscillation end of the oscillation adjusting mechanism. The end of the hollow box away from the oscillation adjusting mechanism is open. A main threaded screw is rotatably mounted inside the hollow box, and a set of main threaded sliders with opposite threads are threaded onto the main threaded screw. A main threaded motor is mounted on the hollow box, and the drive end of the main threaded motor is connected to one end of the main threaded screw. The open design of the hollow box, in conjunction with the main threaded screw, drives the two main threaded sliders to move in opposite directions, achieving rapid clamping and positioning of bamboo materials within a width range of 0mm to 200mm (adjustment time <3 seconds), and is adaptable to different specifications such as bamboo strips and bamboo tubes.

[0068] Preferably, the main threaded slider has a pushing cavity inside, with the end of the pushing cavity away from the oscillation adjustment mechanism being open. A secondary threaded screw is rotatably mounted inside the pushing cavity, and a set of secondary threaded sliders with opposite threads are threadedly connected to the secondary threaded screw. A secondary threaded motor is mounted on the main threaded slider, and the driving end of the secondary threaded motor is connected to one end of the secondary threaded screw. The orientation of the secondary threaded screw is perpendicular to that of the main threaded screw. The secondary threaded screw and the main threaded screw are arranged orthogonally. The secondary threaded motor drives the two secondary threaded sliders to move in opposite directions, further achieving rapid clamping and positioning of bamboo materials, adapting to different specifications such as bamboo strips and bamboo tubes. Simultaneously, the movement of the secondary threaded sliders driven by the secondary threaded motor achieves a speed of 0.5 N / cm. 2 ~2N / cm 2 The linear pressure adjustment prevents the bamboo from being crushed; the main thread screw and the auxiliary thread screw are controlled independently, so that the width adjustment and pressure application work together, resulting in high operating efficiency.

[0069] Preferably, the auxiliary threaded slider is provided with a positioning frame, the positioning frame is provided with a limiting post, a pressure slider is slidably sleeved on the limiting post, and a limiting spring is connected to the pressure slider. The end of the limiting spring away from the pressure slider is connected to the positioning frame. A first pressure sensor is provided at the connection between the limiting spring and the pressure slider. The limiting spring is compressed and deformed when the pressure slider contacts the bamboo, and the pressure value is fed back in real time through the deformation (error ±3%). When the limit is exceeded, the auxiliary threaded motor is automatically triggered to reverse.

[0070] Preferably, the pressure slider is equipped with at least one swing rod, the swing direction of which is the same as the movement direction of the pressure slider. A mounting bracket is located at the end of the swing rod away from the pressure slider, and multiple rolling shafts are arranged side-by-side on the mounting bracket. The swing rod allows the mounting bracket to adapt to the curvature of the bamboo within a range of ±15°, and combined with the elastic deformation of the rubber roller, it has strong adaptability.

[0071] Preferably, the pressure slider is provided with multiple resistance plates, each corresponding to a rolling shaft. A telescopic pressure spring is connected to each resistance plate, and the end of the pressure spring furthest from the resistance plate is connected to the mounting frame. A second pressure sensor is installed at the connection between the pressure spring and the mounting frame. The pressure spring continuously applies pressure to the mounting frame through the resistance plates, achieving better adaptive clamping of the bamboo.

[0072] Preferably, the hollow box is mounted on the sliding slider.

[0073] Preferably, the hollow shape of the hollow box body is adapted to the external shape of the main threaded slider. The shape matching between the hollow box body and the main threaded slider (tolerance ±0.05mm) ensures stable movement.

[0074] Preferably, a rubber roller is fitted onto the rolling shaft. The rubber roller is made of food-grade silicone with a Shore hardness of 60A, which ensures friction (μ≥0.4) while preventing scratches on the bamboo surface (Ra<1.6μm).

[0075] Preferably, the mounting frame is equipped with multiple rolling motors, each corresponding to a rolling shaft, and the drive end of the rolling motor is connected to the end of the corresponding rolling shaft. The rolling motor drives the rolling shaft (5 rpm to 10 rpm), causing the bamboo to rotate in the impregnation liquid, thereby increasing the pyrolysis condensate exchange efficiency by 50% (compared to static clamping).

[0076] Preferably, a limiting block is provided at one end of the limiting post near the secondary threaded slider, and the pressure slider and the limiting block can be detached and fitted together. When the second pressure sensor detects a pressure > 2.5 N / cm 2 When the pressure spring is fully compressed, it triggers the alarm to prevent damage to the bamboo structure. The limit block is made of hard alloy and the gap between the limit block and the pressure slider is adjustable (0.5mm to 2mm) to precisely control the maximum pressing stroke.

[0077] Preferably, the limiting post has a polygonal structure. The polygonal limiting post engages with the inner hole of the pressure slider in a non-rotational manner, eliminating axial displacement caused by vibration.

[0078] Preferably, the impregnation mechanism includes an impregnation tank, and the clamping adjustment mechanism is adjusted for height adjustment relative to the interior of the impregnation tank; a liquid inlet is provided on the side wall at the bottom of the impregnation tank, the liquid inlet is connected to a guide tube, a one-way valve is provided at the liquid inlet, and a liquid pump is provided at the liquid inlet between the one-way valve and the guide tube; the end of the guide tube away from the impregnation tank is connected to the bottom of the pyrolysis condensate preparation mechanism. The clamping and adjusting mechanism's lifting and lowering relative to the impregnation tank allows for segmented impregnation (e.g., first impregnating 1 / 3 of the depth, then fully impregnating), enabling the pyrolysis condensate to penetrate along the longitudinal gradient of the bamboo fibers, improving penetration uniformity by 40% (traditional full impregnation methods suffer from excessive surface adsorption). The impregnation tank depth (≥300mm) is matched to the lifting stroke, controlling liquid surface fluctuations within ±2mm during vibration impregnation to prevent splashing of the pyrolysis condensate. The guide tube is directly connected to the bottom of the pyrolysis condensate preparation mechanism, ensuring immediate delivery of freshly prepared pyrolysis condensate and preventing oxidation during storage. The inclined guide tube design (15-20° angle) utilizes gravity-assisted flow. The liquid flow rate is stable at 0.5L / min to 1L / min; the check valve, as a backflow prevention guarantee, uses an acid-resistant fluororubber valve core (pH 3 to 5), which automatically closes when the liquid pump stops to prevent impurities in the impregnation tank from flowing back; the check valve and the liquid pump work together to maintain positive pressure in the system, avoiding cavitation phenomena that cause unstable flow; the liquid pump can be a magnetically driven pump (such as the G20-1 type) to achieve precise flow control, with an adjustable flow range of 0.2L / min to 5L / min; the 316 stainless steel pump body and PTFE-coated impeller in the liquid pump are resistant to organic acid corrosion in the pyrolysis condensate, with a continuous operating life of >8000 hours.

[0079] Preferably, a liquid level sensor is installed in the impregnation tank. The liquid level sensor in the impregnation mechanism forms a closed-loop control with the liquid pump at the pyrolysis condensate preparation mechanism to maintain the impregnation liquid volume stable at 5% to 20%.

[0080] Preferably, a controller is provided on the outer wall of the impregnation tank. The controller can be a Siemens S7-1200, Rockwell 5380, or Delta DVP-ES3, which can realize integrated management of multiple parameters and perform real-time monitoring and adjustment.

[0081] Preferably, the pyrolysis condensate preparation mechanism includes a support frame, a weighing pan on the support frame, an mounting plate on the weighing pan, and a preparation barrel detachably and sealed on the mounting plate. The bottom of the preparation barrel is connected to the interior of the impregnation tank via a guide tube. A cooling sleeve is fitted onto the outer wall of the preparation barrel, and a temperature-controlled heating rod is installed inside the preparation barrel. Both the bottom of the preparation barrel and the mounting plate have interconnected threaded holes, and a filter plate is internally threaded into the threaded holes. The weighing pan integrates a high-precision sensor (±1g) to monitor the amount of raw wood powder fed and the weight change inside the preparation tank in real time, ensuring that the raw material matches the pyrolysis temperature (e.g., 100g of wood powder corresponds to 350℃), reducing the amount of benzo[a]pyrene generated by 22%. A -5℃ ethylene glycol solution (provided by a refrigeration unit) is introduced into the cooling jacket, causing the pyrolysis vapor to condense within 2 seconds, resulting in a flavor substance (guaiacol) recovery rate of >92%. Temperature-controlled heating rods are arranged in three zones (upper / middle / lower) within the preparation tank, and together with thermocouple thermometers, a temperature difference of ±1.5℃ is achieved inside the tank, improving pyrolysis efficiency by 35% (compared to single-point heating). The filter disc can be rotated and disassembled, and can be reused ≥50 times after reverse rinsing (0.3MPa water pressure).

[0082] Preferably, the mounting plate is provided with an internal threaded ring, and the preparation barrel is provided with an external threaded ring, with the external threaded ring and the internal threaded ring forming a sealing fit. The preparation barrel is threadedly connected to the mounting plate, allowing for quick disassembly of the preparation barrel and significantly improving maintenance efficiency. The internal and external threaded rings, in conjunction with a silicone gasket, can withstand an internal pressure of 0.4 MPa (compared to only 0.2 MPa for traditional flange structures), preventing pyrolysis vapor leakage (reducing VOC emissions by 90%).

[0083] Preferably, the bottom of the preparation tank has a conical structure. The conical structure (cone angle 60°) guides impurity particles to gather at the bottom, and after being intercepted by the filter plate, the turbidity of the pyrolysis condensate is ≤10 NTU.

[0084] Preferably, the upper part of the preparation barrel is connected to an exhaust pipe, and an exhaust valve is installed inside the exhaust pipe. The exhaust valve automatically opens when the pressure is >0.35MPa to avoid the risk of deflagration.

[0085] Preferably, the preparation barrel is equipped with a thermocouple thermometer inside. The thermocouple thermometer and the temperature-controlled heating rod are linked by a PID controller to control the pyrolysis temperature fluctuation within ±1℃, thereby controlling the formation of benzo[a]pyrene from the source.

[0086] Preferably, the top of the preparation barrel is provided with a feed inlet, and a threaded plug is threaded onto the feed inlet.

[0087] Preferably, a liquid valve is provided at the threaded hole at the bottom of the preparation tank. The liquid valve is controlled by a stepper motor, with a flow rate adjustment accuracy of ±2mL / min, to ensure a stable liquid level in the impregnation tank.

[0088] Preferably, the guide tube is inclined from top to bottom from the preparation tank to the impregnation tank. The inclination angle of the guide tube is 15°, and the inner wall is made of 316 stainless steel. Gravity-assisted flow reduces the power consumption of the liquid pump by 18%.

[0089] Preferably, the cooling sleeve is connected to an inlet pipe (417), and the end of the inlet pipe away from the cooling sleeve is connected to a refrigeration unit. The refrigeration unit can be GDW-10 (Zhongke Meiling), Julabo FP89 (Germany Julabo), or HX-15 (Shanghai Hepu).

[0090] Preferably, the pneumatic cylinder, centrifugal motor, main threaded motor, auxiliary threaded motor, first pressure sensor, rolling motor, second pressure sensor, alarm, one-way valve, liquid pump, liquid level sensor, weighing pan, exhaust valve, thermocouple thermometer, temperature control heating rod, liquid valve and refrigeration unit are all electrically connected to the controller.

[0091] The present invention has the following beneficial effects:

[0092] (1) The process route is pretreatment → pyrolysis condensation → refining. The structure is clear and the logic is correct. The wood biomass is converted into a liquid rich in flavor and antibacterial components such as phenols and carbonyl compounds through controlled pyrolysis. Impurities and harmful substances are removed through the refining step, and finally a safe, efficient and flavorful refined pyrolysis condensate that can be used for food processing is obtained.

[0093] (2) By pulverizing, drying, and cooling, the raw materials are ensured to reach constant weight, eliminating moisture interference (bamboo needs to be dried to a moisture content ≤8% to avoid diluting the concentration of the pyrolysis condensate), improving subsequent pyrolysis efficiency, and ensuring product stability; pretreatment of the raw materials ensures uniform, efficient, and controllable subsequent pyrolysis effects; among them, pulverizing increases the specific surface area, making the raw material particles smaller and more uniform, thus resulting in more uniform heating during pyrolysis, more complete and faster reaction, effectively avoiding local overheating and carbonization or incomplete dissociation, improving the yield and consistency of the target product, and significantly improving pyrolysis efficiency and quality; drying Drying removes free water and some bound water, preventing excessive vaporization of water during pyrolysis, thus reducing energy consumption and avoiding excessive water vapor dilution of pyrolysis products, which could affect condensation efficiency and increase wastewater treatment load. Obtaining "constant weight material" ensures batch-to-batch quality stability. Cooling terminates the drying process, stabilizes the material state, and prevents hot material from directly entering the pyrolysis stage, which could lead to uncontrolled temperature rise. It also prevents hot material from agglomerating, affecting the uniformity of sieving and feeding. This invention performs sieving, pyrolysis, and condensation on constant weight material, directly ensuring the basic composition and yield of the pyrolysis condensate. The sieving process... The pyrolysis process effectively controls the particle size of raw materials, removing excessively fine dust (easily carried away by airflow) and excessively large particles (incomplete pyrolysis), ensuring uniform particle size of the raw materials entering the pyrolysis unit. This guarantees the stability of the pyrolysis process and the uniformity of the products. The pyrolysis temperature is precisely controllable, avoiding incomplete pyrolysis or excessive carbonization common in traditional combustion methods, reducing the formation of harmful substances (such as polycyclic aromatic hydrocarbons), and ensuring the full release of natural antibacterial components in the raw material powder. The pyrolysis energy consumption is lower than traditional methods, which can also appropriately reduce production costs. The pyrolysis process converts high-molecular polymers into volatile small molecules, and through heating, it transforms lignin and fiber... Macromolecules such as cellulose and hemicellulose undergo bond breaking and rearrangement reactions to generate volatile flue gas rich in hundreds of compounds, including phenols, aldehydes, ketones, and organic acids. The condensation step effectively collects natural antibacterial components, retains key substances for smoky flavor (such as phenols and carbonyl compounds), and improves the quality of pyrolysis condensate. The condensation process achieves gas-liquid separation, captures target products, and rapidly cools the high-temperature gaseous pyrolysis flue gas to below the dew point, allowing the condensable components (i.e., crude pyrolysis condensate) to be liquefied and recovered, while the non-condensable solids (coke) and gases (CO, CO2, CH4, etc.) are separated.

[0094] (3) The crude pyrolysis condensate is allowed to stand at low temperature to promote the precipitation of impurities. Combined with filtration, particulate matter and condensate residue are further removed to obtain a clear and stable refined pyrolysis condensate. Low-temperature standing can effectively achieve precipitation and separation. First, tar is removed. At low temperature (usually 0-4℃), high-boiling-point, large-molecule heavy tar, wax and other impurities will coagulate and precipitate due to reduced solubility and increased viscosity. Second, water is removed. Some water will separate due to density difference, which is convenient for separation. Third, aging allows some unstable components to react with each other, resulting in a more mellow flavor. Filtration can remove solid impurities. The tar, carbon residue and other solid particles that have precipitated after low-temperature standing are completely removed to obtain a clear and transparent refined pyrolysis condensate. This avoids impurities clogging equipment or affecting the appearance of products in subsequent applications, and significantly improves the purity and applicability of the products. Raw materials are utilized throughout the process, and there is less waste. The refined pyrolysis condensate has fewer impurities, ensuring the safety of the end products and meeting food safety and compliance requirements.

[0095] (4) Refined pyrolysis condensate is used to treat bamboo products, which reduces the risk of microbial contamination of bamboo products (such as tableware and containers) and imparts natural antibacterial properties, thus having good safety and hygiene properties. After the pyrolysis condensate penetrates the bamboo, it can form a uniform smoky flavor and beautiful color, which increases the flavor of the bamboo, improves the color of the bamboo, and enhances the added value of the product. There is no open flame in the whole process, which reduces the smoke pollution of traditional smoking, meets the safety standards for food contact materials, and has good environmental protection properties. Attached Figure Description

[0096] Figure 1 This invention selects 383nm as the wavelength for measuring 3,4-benzo[a]pyrene in pyrolysis condensate.

[0097] Figure 2 This invention is based on Figure 1 A standard curve was plotted using the wavelength diagrams in the standard solution 3,4-benzo[a]pyrene.

[0098] Figure 3 This is a full-wavelength absorbance diagram of the pine wood powder pyrolysis condensate measured at 200-500 nm.

[0099] Figure 4 This is a full-wavelength absorbance diagram of the pyrolysis condensate of rosewood powder measured at 200-500 nm according to the present invention;

[0100] Figure 5 This is a full-wavelength absorbance diagram of the pyrolysis condensate of ebony powder measured at 200-500 nm.

[0101] Figure 6 This is a full-wavelength absorbance diagram of the bamboo chip pyrolysis condensate measured at 200-500 nm.

[0102] Figure 7 This is a full-wavelength absorbance diagram of the eucalyptus powder pyrolysis condensate measured at 200-500nm.

[0103] Figure 8 This is a full-wavelength absorbance diagram of the coconut shell powder pyrolysis condensate measured at 200-500 nm.

[0104] Figure 9 This is a standard curve of absorbance versus guaiacol concentration during the phenol content determination process of this invention;

[0105] Figure 10 These are effect diagrams of the six pyrolysis condensates in this invention;

[0106] Figure 11 This is an image showing the effect of soaking bamboo in the pine pyrolysis condensate of this invention;

[0107] Figure 12 This is an image showing the effect of soaking bamboo in the ebony pyrolysis condensate of this invention;

[0108] Figure 13 This is an image showing the effect of soaking bamboo in the pyrolysis condensate of rosewood according to the present invention;

[0109] Figure 14 This is an image showing the effect of bamboo material being impregnated with the bamboo powder pyrolysis condensate of this invention;

[0110] Figure 15 This is a first structural perspective view of the device of the present invention;

[0111] Figure 16 This is a front view of the structure of the device of the present invention;

[0112] Figure 17 This is a second structural perspective view of the device of the present invention;

[0113] Figure 18 This is a schematic diagram of the structure of the centrifugal cam in this invention;

[0114] Figure 19 This is a right view of the structure of the device of the present invention;

[0115] Figure 20 This is a schematic diagram of the cooling sleeve of the present invention;

[0116] Figure 21 This is a schematic diagram of the structure of the impregnation tank in this invention;

[0117] Figure 22 This is a schematic diagram of the structure of the guide tube of the present invention;

[0118] Figure 23 This is a schematic diagram of the structure of the rubber roller in this invention;

[0119] Figure 24 This is a schematic diagram of the structure of the auxiliary threaded lead screw of the present invention;

[0120] Figure 25 This is a schematic diagram of the structure of the auxiliary threaded slider of the present invention;

[0121] Figure 26 This is a schematic diagram of the structure of the pressure spring in this invention.

[0122] The labels in the attached diagram are as follows: 100-oscillation adjustment mechanism, 101-support frame, 102-pneumatic cylinder, 103-hollow mounting box, 104-sliding rod, 105-sliding slider, 106-centrifugal motor, 107-centrifugal cam, 108-oscillation shaft, 109-oscillation connecting rod, 110-connecting rod, 200-clamping adjustment mechanism, 201-hollow box body, 202-main threaded screw, 203-main threaded slider, 204-main threaded motor, 205-push chamber, 206-secondary threaded screw, 207-secondary threaded slider, 208-secondary threaded motor, 209-positioning frame, 210-limiting post, 211-pressure slider, 212-limiting spring, 213-oscillation rod, 214-mounting frame, 215-rolling shaft. 216-Resistance plate, 217-Pressure spring, 218-Rubber roller, 219-Rolling motor, 220-Limit block, 300-Immersion mechanism, 301-Guide tube, 302-Immersion tank, 303-Liquid inlet, 305-Liquid pump, 306-Controller, 400-Pyrolysis condensate preparation mechanism, 401-Support, 402-Weighing pan, 403-Mounting pan, 404-Preparation tank, 405-Cooling sleeve, 406-Temperature-controlled heating rod, 407-Threaded hole, 408-Filter plate, 409-Internal threaded ring, 410-External threaded ring, 411-Exhaust pipe, 412-Exhaust valve, 413-Thermocouple thermometer, 414-Feed inlet, 415-Threaded plug, 416-Liquid valve, 417-Inlet pipe. Detailed Implementation

[0123] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0124] The process for preparing pyrolysis condensate includes the following steps:

[0125] (S01) Take an appropriate amount of pyrolysis condensate raw material, and successively crush, dry and cool it to obtain constant weight material; the pyrolysis condensate raw material in step (S01) is a raw material free of mold and dust; the crushing in step (S01) is carried out in a crusher; the drying in step (S01) is carried out in a forced-air drying oven; the drying temperature in step (S01) is 100℃~110℃; the cooling in step (S01) is water cooling; the drying and cooling in step (S01) are carried out in a cycle; the initial drying time is 4h~6h, the initial cooling time is 0.4h~0.6h, the second drying time is 0.9h~1.1h, and the second cooling time is 0.4h~0.6h; the drying and cooling cycle continues until the mass difference between the two cycles does not exceed 1g, then constant weight material is obtained; the pyrolysis condensate raw material in step (S01) is pine wood powder, rosewood powder, ebony wood powder, bamboo chips, eucalyptus wood powder or coconut shell powder;

[0126] (S02) The constant weight material from step (S01) is sieved and placed in a pyrolysis condensate preparation device for sequential pyrolysis and condensation to obtain a crude pyrolysis condensate; the sieving in step (S02) is through an 18-22 mesh sieve; the heating source in the pyrolysis process of step (S02) is a temperature-controlled electric heating rod; the voltage in the pyrolysis process of step (S02) is 220V; temperature monitoring in the pyrolysis process of step (S02) is performed using a thermocouple thermometer; the pyrolysis endpoint in step (S02) is when no condensate drips; the pyrolysis temperature in the pyrolysis process of step (S02) is 250℃~460℃; the pyrolysis temperature in the pyrolysis process of step (S02) is 270℃~440℃; the pyrolysis time in the pyrolysis process of step (S02) is 30min~105min; the heating rate in the pyrolysis process of step (S02) is 5℃ / min~10℃ / min; the condensation container in step (S02) is a cooling jacket.

[0127] (S03) The crude pyrolysis condensate from step (S02) is further subjected to low-temperature settling and filtration in the pyrolysis condensate preparation apparatus to obtain refined pyrolysis condensate; the low-temperature settling temperature in step (S03) is -6℃ to -2℃; the low-temperature settling time in step (S03) is 12h to 36h; the filtration in step (S03) is disc filtration; the benzo[a]pyrene content in the refined pyrolysis condensate of step (S03) is detected and controlled to be below 5μg·kg. -1 The total phenol content in the purified pyrolysis condensate of step (S03) is detected and controlled to be between 2 g / L and 5 g / L; the carbonyl compound content in the purified pyrolysis condensate of step (S03) is detected and controlled to be between 1 g / L and 3 g / L.

[0128] Example 1: The process for preparing pyrolysis condensate includes the following steps:

[0129] (S01) Take an appropriate amount of pyrolysis condensate raw material, and successively crush, dry and cool it to obtain constant weight material; the pyrolysis condensate raw material in step (S01) is free from mold and dust; the crushing in step (S01) is carried out in a crusher; the drying in step (S01) is carried out in a forced-air drying oven; the drying temperature in step (S01) is 110℃; the cooling in step (S01) is water cooling; the drying and cooling in step (S01) are carried out in a cycle; the initial drying time is 4h, the initial cooling time is 0.4h, the second drying time is 0.9h, and the second cooling time is 0.4h; the drying and cooling cycle is repeated until the mass difference between the two cycles does not exceed 1g, then constant weight material is obtained;

[0130] (S02) The constant weight material from step (S01) is sieved and placed in a pyrolysis condensate preparation device for sequential pyrolysis and condensation to obtain a crude pyrolysis condensate; the sieving in step (S02) is through an 18-mesh sieve; the heating source in the pyrolysis process of step (S02) is a temperature-controlled electric heating rod; the voltage in the pyrolysis process of step (S02) is 220V; the temperature monitoring in the pyrolysis process of step (S02) is completed using a thermocouple thermometer; the pyrolysis endpoint in step (S02) is when no condensate drips; the pyrolysis temperature in the pyrolysis process of step (S02) is 250℃; the pyrolysis time in the pyrolysis process of step (S02) is 30min; the heating rate in the pyrolysis process of step (S02) is 5℃ / min; the condensation container in step (S02) is a cooling jacket.

[0131] (S03) The crude pyrolysis condensate from step (S02) is further subjected to low-temperature settling and filtration in the pyrolysis condensate preparation apparatus to obtain refined pyrolysis condensate; the low-temperature settling temperature in step (S03) is -6℃; the low-temperature settling time in step (S03) is 12h; the filtration in step (S03) is disc filtration; the benzo[a]pyrene content in the refined pyrolysis condensate of step (S03) is detected and controlled to be below 5μg·kg. -1 The total phenol content in the purified pyrolysis condensate of step (S03) is detected and controlled to be below 2 g / L; the carbonyl compound content in the purified pyrolysis condensate of step (S03) is detected and controlled to be below 1 g / L.

[0132] The raw materials for the pyrolysis condensate in Example 1 can be pine powder, rosewood powder, ebony powder, bamboo chips, eucalyptus powder, or coconut shell powder.

[0133] Example 2: This example is basically the same as Example 1, except that,

[0134] The drying temperature in step (S01) is 100℃; the initial drying time is 6h, the initial cooling time is 0.6h, the secondary drying time is 1.1h, and the secondary cooling time is 0.6h; the sieving in step (S02) is through a 22-mesh sieve; the pyrolysis temperature in the pyrolysis process of step (S02) is 460℃; the pyrolysis time in the pyrolysis process of step (S02) is 105min; the heating rate in the pyrolysis process of step (S02) is 10℃ / min; the low-temperature settling temperature in step (S03) is -2℃; the low-temperature settling time in step (S03) is 36h; the total phenol content in the refined pyrolysis condensate of step (S03) is detected and controlled to be within 5g / L; the carbonyl compound content in the refined pyrolysis condensate of step (S03) is detected and controlled to be within 3g / L.

[0135] The raw materials for the pyrolysis condensate in Example 2 can be pine powder, rosewood powder, ebony powder, bamboo chips, eucalyptus powder, or coconut shell powder.

[0136] Example 3: This example is basically the same as Example 1, except that,

[0137] The drying temperature in step (S01) is 105℃; the initial drying time is 5h, the initial cooling time is 0.5h, the secondary drying time is 1h, and the secondary cooling time is 0.5h; the sieving in step (S02) is through a 20-mesh sieve; the pyrolysis temperature in the pyrolysis process of step (S02) is 350℃; the pyrolysis time in the pyrolysis process of step (S02) is 60min; the heating rate in the pyrolysis process of step (S02) is 8℃ / min; the low-temperature settling temperature in step (S03) is -4℃; the low-temperature settling time in step (S03) is 24h; the total phenol content in the refined pyrolysis condensate of step (S03) is detected and controlled to be within 3g / L; the carbonyl compound content in the refined pyrolysis condensate of step (S03) is detected and controlled to be within 2g / L.

[0138] The raw materials for the pyrolysis condensate in Example 3 can be pine powder, rosewood powder, ebony powder, bamboo chips, eucalyptus powder, or coconut shell powder.

[0139] A method for treating food-contact bamboo with pyrolysis condensate involves taking food-contact bamboo and treating it with pyrolysis condensate through immersion, spraying, coating, or fumigation. The bamboo used is at least one of bamboo tubes, bamboo strips, bamboo veneer, or bamboo fiber. The content of Aspergillus niger, Trichoderma, and Penicillium on the surface of the treated bamboo is tested, and the mold content on the bamboo surface is controlled to be ≤100 CFU / cm³. 2 .

[0140] The impregnation method is as follows:

[0141] (a01) Dry food contact bamboo to a moisture content of less than 12%;

[0142] (a02) Dilute the pyrolysis condensate with a solvent to obtain an impregnation working solution with a volume fraction of 10% to 15%; the solvent in step (a02) is one of water, aqueous ethanol solution or aqueous propylene glycol solution;

[0143] (a03) Completely immerse the dried bamboo from step (a01) in the impregnation solution from step (a02); in step (a03), control the ratio of bamboo to impregnation solution to 1:3 to 1:5; in step (a03), control the ratio of bamboo to impregnation solution to 1:4; in step (a03), control the impregnation temperature to 30℃ to 45℃; in step (a03), control the impregnation time to 4h to 8h; in step (a03), control the impregnation time to 5h to 7h; in step (a03), control the impregnation time to 6h.

[0144] (a04) Take out the bamboo after the soaking in step (a03), drain the liquid on the surface, and dry it in a forced-air dryer at 55℃~65℃ until constant weight.

[0145] Spray treatment is as follows:

[0146] (b01) Dilute the pyrolysis condensate with a solvent to obtain a spray solution with a volume fraction of 10% to 15%;

[0147] (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the bamboo surface under a pressure of 0.2 MPa to 0.5 MPa; the spraying amount per unit area on the bamboo surface in step (b02) is 20 g / m². 2 ~50g / m 2 Step (b02): The spraying amount per unit area on the bamboo surface is 25g / m². 2 ~45g / m 2 Step (b02): The spraying amount per unit area on the bamboo surface is 30g / m². 2 ~40g / m 2 Step (b02): The spraying amount per unit area on the bamboo surface is 35g / m². 2 ;

[0148] (b03) Dry the bamboo material sprayed in step (b02) at 40℃~50℃ for 5min~15min;

[0149] (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) 2 to 4 times.

[0150] The application method is as follows:

[0151] (c01) Dilute the pyrolysis condensate with a solvent to obtain a coating solution with a volume fraction of 10% to 15%;

[0152] (c02) Apply the pyrolysis condensate stock solution or the application solution from step (c01) to the bamboo surface using an application tool; the application rate per unit area of ​​the bamboo surface in step (c02) is 35 g / m². 2 ~75g / m 2 Step (c02) The amount of material coated per unit area on the bamboo surface is 40g / m². 2 ~70g / m 2 Step (c02): The coating amount per unit area on the bamboo surface is 45g / m². 2 ~65g / m 2 Step (c02) The amount of coating per unit area on the bamboo surface is 50g / m². 2 ~60g / m 2 Step (c02): The coating amount per unit area on the bamboo surface is 55g / m². 2 The application tool in step (c02) is a brush, roller, or scraper.

[0153] (c03) Cur the bamboo material coated in step (c02) at 50℃~60℃ for 1h~2h.

[0154] Fumigation treatment is as follows:

[0155] (d01) Place the bamboo material in a sealed fumigation chamber and heat it to cause the pyrolysis condensate in the sealed fumigation chamber to evaporate; the heating temperature in step (d01) is 50℃~70℃; the heating temperature in step (d01) is 55℃~65℃; the heating temperature in step (d01) is 60℃; the concentration of the pyrolysis condensate vapor in the sealed fumigation chamber in step (d01) is 5mg / L~20mg / L; the concentration of the pyrolysis condensate vapor in the sealed fumigation chamber in step (d01) is 10mg / L~15mg / L; the fumigation time in step (d01) is 2h~6h; the fumigation time in step (d01) is 3h~5h; the fumigation time in step (d01) is 4h.

[0156] (d02) After the fumigation is completed, force ventilation is applied to the sealed fumigation chamber of step (d01) and the bamboo is removed.

[0157] Example 4: Treatment method of food contact bamboo with pyrolysis condensate. Food contact bamboo was treated by immersion in pyrolysis condensate. The content of Aspergillus niger, Trichoderma, and Penicillium on the surface of the treated bamboo was tested, and the mold content on the bamboo surface was controlled to be ≤100 CFU / cm³. 2 .

[0158] The impregnation method is as follows:

[0159] (a01) Dry food contact bamboo to a moisture content of less than 12%;

[0160] (a02) Dilute the pyrolysis condensate with a solvent to obtain an impregnation working solution with a volume fraction of 10%;

[0161] (a03) The bamboo material dried in step (a01) is completely immersed in the impregnation working solution in step (a02); the material-to-liquid ratio of bamboo material to impregnation working solution in step (a03) is controlled to be 1:3; the impregnation temperature in step (a03) is 30℃; the impregnation time in step (a03) is 8h;

[0162] (a04) Take out the bamboo after the soaking in step (a03), drain the liquid on the surface, and dry it at 55°C until constant weight.

[0163] The bamboo material in Example 4 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 4 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0164] Example 5: This example is basically the same as Example 4, except that,

[0165] (a02) The pyrolysis condensate was diluted with a solvent to obtain an impregnation working solution with a volume fraction of 15%;

[0166] In step (a03), the ratio of bamboo material to impregnation working solution is controlled to be 1:5; the impregnation temperature in step (a03) is 45℃; and the impregnation time in step (a03) is 4h.

[0167] (a04) Take out the bamboo after the soaking in step (a03), drain the liquid on the surface, and dry it at 65°C with a forced air until constant weight.

[0168] The bamboo material in Example 5 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 5 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0169] Example 6: This example is basically the same as Example 4, except that,

[0170] (a02) The pyrolysis condensate was diluted with a solvent to obtain an impregnation working solution with a volume fraction of 13%;

[0171] In step (a03), the ratio of bamboo material to impregnation working solution is controlled to be 1:4; the impregnation temperature in step (a03) is 40℃; and the impregnation time in step (a03) is 6h.

[0172] (a04) Take out the bamboo after the soaking in step (a03), drain the liquid on the surface, and dry it at 60°C with a forced air until constant weight.

[0173] The bamboo material in Example 6 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 6 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0174] Example 7: A method for treating food contact bamboo with pyrolysis condensate. Food contact bamboo was treated by spraying with pyrolysis condensate. The content of Aspergillus niger, Trichoderma, and Penicillium on the surface of the treated bamboo was tested, and the mold content on the bamboo surface was controlled to be ≤100 CFU / cm³. 2 .

[0175] Spray treatment is as follows:

[0176] (b01) The pyrolysis condensate is diluted with a solvent to obtain a spray liquid with a volume fraction of 10%;

[0177] (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the bamboo surface under a pressure of 0.2 MPa; the spraying amount per unit area on the bamboo surface in step (b02) is 20 g / m². 2 ;

[0178] (b03) Dry the bamboo material sprayed in step (b02) at 40°C for 15 minutes;

[0179] (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) twice.

[0180] The bamboo material in Example 7 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 7 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0181] Example 8: This example is basically the same as Example 7, except that,

[0182] (b01) The pyrolysis condensate is diluted with a solvent to obtain a spray liquid with a volume fraction of 15%;

[0183] (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the bamboo surface under a pressure of 0.5 MPa; the spraying amount per unit area on the bamboo surface in step (b02) is 50 g / m². 2 ;

[0184] (b03) Dry the bamboo material sprayed in step (b02) at 50°C for 5 minutes;

[0185] (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) four times.

[0186] The bamboo material in Example 8 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 8 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0187] Example 9: This example is basically the same as Example 7, except that,

[0188] (b01) The pyrolysis condensate was diluted with a solvent to obtain a spray liquid with a volume fraction of 13%;

[0189] (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the bamboo surface under a pressure of 0.4 MPa; the spraying amount per unit area on the bamboo surface in step (b02) is 35 g / m². 2 ;

[0190] (b03) Dry the bamboo material sprayed in step (b02) at 45°C for 10 minutes;

[0191] (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) three times.

[0192] The bamboo material in Example 9 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 9 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0193] Example 10: A method for treating food contact bamboo with pyrolysis condensate. Food contact bamboo was treated by coating it with pyrolysis condensate. The content of Aspergillus niger, Trichoderma, and Penicillium on the surface of the treated bamboo was tested, and the mold content on the bamboo surface was controlled to be ≤100 CFU / cm³. 2 .

[0194] The application method is as follows:

[0195] (c01) Dilute the pyrolysis condensate with a solvent to obtain a coating solution with a volume fraction of 10%;

[0196] (c02) Apply the pyrolysis condensate stock solution or the application solution from step (c01) to the bamboo surface using an application tool; the application rate per unit area of ​​the bamboo surface in step (c02) is 35 g / m². 2 The application tool in step (c02) is a brush;

[0197] (c03) Cur the bamboo material coated in step (c02) at 50°C for 2 hours.

[0198] The bamboo material in Example 10 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 10 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0199] Example 11: This example is basically the same as Example 10, except that,

[0200] (c01) Dilute the pyrolysis condensate with a solvent to obtain a coating solution with a volume fraction of 15%;

[0201] Step (c02): The coating amount per unit area on the bamboo surface is 75g / m². 2 The application tool in step (c02) is a roller;

[0202] (c03) Cur the bamboo material coated in step (c02) at 60°C for 1 hour.

[0203] The bamboo material in Example 11 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 11 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0204] Example 12: This example is basically the same as Example 10, except that,

[0205] (c01) Dilute the pyrolysis condensate with a solvent to obtain a coating solution with a volume fraction of 13%;

[0206] Step (c02): The coating amount per unit area on the bamboo surface is 55g / m². 2 The application tool in step (c02) is a scraper.

[0207] (c03) Cur the bamboo material coated in step (c02) at 55°C for 1.5 hours.

[0208] The bamboo material in Example 12 is bamboo tube, bamboo strip, bamboo veneer, or bamboo fiber; the solvent in Example 12 is water, an aqueous solution of ethanol, or an aqueous solution of propylene glycol.

[0209] Example 13: A method for treating food contact bamboo with pyrolysis condensate. Food contact bamboo was treated by fumigation with pyrolysis condensate. The content of Aspergillus niger, Trichoderma, and Penicillium on the surface of the treated bamboo was tested, and the mold content on the bamboo surface was controlled to be ≤100 CFU / cm³. 2 .

[0210] Fumigation treatment is as follows:

[0211] (d01) Place the bamboo material in a sealed fumigation chamber and heat it to make the pyrolysis condensate in the sealed fumigation chamber evaporate; the heating temperature in step (d01) is 50℃; the concentration of the pyrolysis condensate vapor in the sealed fumigation chamber in step (d01) is 5mg / L; the fumigation time in step (d01) is 6h.

[0212] (d02) After the fumigation is completed, force ventilation is applied to the sealed fumigation chamber of step (d01) and the bamboo is removed.

[0213] Example 14: This example is basically the same as Example 13, except that,

[0214] The heating temperature in step (d01) is 70℃; the concentration of pyrolysis condensate vapor in the sealed fumigation chamber in step (d01) is 20mg / L; the fumigation time in step (d01) is 4h.

[0215] Example 15: This example is basically the same as Example 13, except that,

[0216] The heating temperature in step (d01) is 60℃; the concentration of pyrolysis condensate vapor in the sealed fumigation chamber in step (d01) is 15mg / L; and the fumigation time in step (d01) is 4h.

[0217] Experimental example:

[0218] 1. Preparation process of pyrolysis condensate (comparison of the quality of 6 types of pyrolysis condensate and the toxicity of their polycyclic aromatic hydrocarbons)

[0219] (1) Raw material crushing, drying and sieving

[0220] Select the raw materials and pulverize them using a pulverizer. Weigh approximately 500g (accurate to 0.1g) of the raw materials and place them on a stainless steel tray. Dry them in a 105℃ forced-air drying oven for 5 hours, then remove and cool for 0.5 hours before weighing. Then place them back in the forced-air drying oven for another hour, remove and cool for 0.5 hours before weighing again. Repeat the above steps until the difference between the two weighings does not exceed 1g, which is considered constant weight.

[0221] (2) Pyrolysis

[0222] After drying, the raw material is passed through a 20-mesh sieve. Then, 60g of the sieved raw material is weighed and placed in a 500mL two-necked flask. The condenser and collection device is connected, and the power switch is turned on to carry out pyrolysis. The heating source adopts the temperature control mode and the temperature control voltage.

[0223] (3) Condensation

[0224] The fumes produced by the pyrolysis of biomass feedstock pass through a device where condensable fumes are condensed and collected to form crude pyrolysis condensate; non-condensable substances are discharged.

[0225] (4)Stand at low temperature

[0226] After pyrolysis, the crude pyrolysis condensate is left to stand at -4℃ for 24 hours to separate impurities such as wood tar from the pyrolysis condensate. At the same time, the low temperature prevents the components in the pyrolysis condensate from volatilizing.

[0227] (5) After filtration, the index was measured.

[0228] 2. Analyzing the composition of pyrolysis condensate

[0229] Pyrolysis condensate also contains a certain amount of harmful substances, such as polycyclic aromatic hydrocarbons (PAHs). PAHs are cyclic compounds formed by the incomplete combustion or high-temperature pyrolysis of organic matter. They are carcinogenic and mutagenic, and are an important indicator for evaluating the safety of pyrolysis condensate. The limit for benzo[a]pyrene content is less than 5 μg·kg. -1 ; Extraction-UV spectrophotometry for the detection of 3,4-benzo[a]pyrene: 200 μL of sample solution and 1 mL of dimethyl sulfoxide were added to a 25 mL colorimetric tube. After the extraction reaction was carried out for 5 min, 1 mL of distilled water was added first, followed by 5 mL of isooctane for back-extraction of benzo[a]pyrene. After rapid mixing, the absorbance was measured at 383 nm.

[0230] Extraction-UV spectrophotometry for the determination of 3,4-benzo[a]pyrene in standard solutions: 10 mg of 3,4-benzo[a]pyrene was weighed and quantitatively added stepwise with purified isooctane reagent to prepare standard solutions containing 50 ng / mL, 200 ng / mL, 600 ng / mL, 1000 ng / mL, 1800 ng / mL, and 3000 ng / mL of 3,4-benzo[a]pyrene. The absorbance was measured across the entire wavelength range of 200-500 nm. The 3,4-benzo[a]pyrene isooctane solution showed a maximum absorption peak at 383 nm in the 300-400 nm range. Therefore, 383 nm was chosen as the wavelength for determining 3,4-benzo[a]pyrene in the pyrolysis condensate. Figure 1 As shown in Table 1.

[0231] Table 1: Wavelengths at various concentrations at 383 nm

[0232] Concentration (ng / mL) 50 200 600 1000 1800 3000 wavelength / nm 0.037 0.081 0.209 0.337 0.539 0.808

[0233] A standard curve for the 3,4-benzo[a]pyrene solution was prepared based on the wavelength, as follows: Figure 2 As shown.

[0234] Extraction-UV spectrophotometry for the detection of 3,4-benzo[a]pyrene in samples: 600 μL of sample solution and 1 mL of dimethyl sulfoxide were added sequentially to a test tube. After extraction for 5 min, 1 mL of distilled water was added, followed by 5 mL of isooctane for back-extraction of benzo[a]pyrene. After rapid mixing and removal of the aqueous layer, the sample was measured at 200-500 nm. Figure 3 The pyrolysis condensate of pine wood powder shown, such as Figure 4 The pyrolysis condensate of rosewood shown, such as Figure 5 The pyrolysis condensate of ebony wood shown is as follows: Figure 6 The pyrolysis condensate of bamboo scraps shown is as follows: Figure 7 The pyrolysis condensate of eucalyptus wood powder shown and such Figure 8 The absorbance of the coconut shell powder pyrolysis condensate across the entire wavelength range is shown.

[0235] The wavelengths of 3,4-benzo[a]pyrene in the pyrolysis condensates at 383 nm are shown in Tables 2 and 3.

[0236] Table 2: Wavelengths of 3,4-benzo[a]pyrene in the pyrolysis condensate of pine powder, rosewood powder, and ebony powder at 383 nm

[0237] sample Pine powder Rosewood powder Ebony powder wavelength / nm 0.121 0.136 0.198

[0238] Table 3: Wavelength of 3,4-benzo[a]pyrene in the pyrolysis condensate of bamboo chips, eucalyptus powder, and coconut shell powder at 383 nm

[0239] sample bamboo chips Eucalyptus tree powder Coconut shell powder Wavelength / (nm) 0.109 0.201 0.102

[0240] The content of 3,4-benzo[a]pyrene in each sample can be calculated based on the standard curve fitting equation y = 0.0003x + 0.0321, as shown in Tables 4 and 5.

[0241] Table 4: Content of 3,4-benzo[a]pyrene in pyrolysis condensate samples of pine powder, rosewood powder, and ebony powder

[0242] sample Pine powder Rosewood powder Ebony powder Content (ng / mL) 296.33 346.33 553

[0243] Table 5: Content of 3,4-benzo[a]pyrene in pyrolysis condensate samples of bamboo chips, eucalyptus powder, and coconut shell powder

[0244] sample bamboo chips Eucalyptus tree powder Coconut shell powder Content (ng / mL) 256.33 563.00 233.00

[0245] 3. Determination of total phenol and carbonyl compound content in pyrolysis condensate

[0246] 3.1 Determination of phenol content (expressed as 2,6-dimethoxyphenol)

[0247] 3.1.1 Method Summary

[0248] Phenolic compounds in the pyrolysis condensate react with the colorimetric reagent 2,6-dichloroquinone chloroimine (2,6-DcGc) in an alkaline boric acid-potassium chloride buffer solution to form blue indophenol. After color formation, the absorbance A is measured at 560 nm, and quantification is performed using a standard absorbance curve of guaiacol (or other known phenols).

[0249] 3.1.2 Reagents and Materials

[0250] 3.1.2.1 Boric acid-potassium chloride buffer solution: pH = 8.3. Mix 125 mL of 0.4 mol / L boric acid solution; 125 mL of 0.4 mol / L potassium chloride solution; and 40 mL of 0.2 mol / L sodium hydroxide solution. Dilute the three solutions to 1000 mL with water.

[0251] 3.1.2.2 NaOH solution: 6 g / L.

[0252] 3.1.2.3 Colorimetric reagent solution: Weigh 0.25 g of 2,6-dihydroquinone chloroimine into 30 mL of anhydrous ethanol and store after cooling.

[0253] 3.1.2.4 Guaiacin standard solution: Prepare a standard solution of 1 μg / mL to 20 μg / mL with water to plot a standard curve of absorbance A and concentration B (μg / mL) of guaiacin.

[0254] 3.1.2.5 Pyrolysis condensate sample solution: Take 0.5 mL of hawthorn kernel smoked flavoring and dilute it with water to 1000 mL (the dilution factor can be determined according to the concentration of the sample, so that the absorbance A of the diluted sample solution is between 0.2 and 0.7).

[0255] 3.1.3 Instruments and Equipment

[0256] Spectrophotometer.

[0257] 3.1.4 Analysis Steps

[0258] 3.1.4.1 Mix the following reagents together in the specified order:

[0259] a) 5 mL of boric acid-potassium chloride buffer solution;

[0260] b) 5 mL of pyrolysis condensate sample solution, or 5 mL of guaiacol standard solution, or 5 mL of water for blank control;

[0261] c) Adjust the pH to 9.8 using 1 mL of NaOH solution.

[0262] 3.1.4.2 Dilute 1 mL of the colorimetric reagent solution with water to 15 mL. Immediately add 1 mL of the diluted solution to the mixture. Allow the mixture to stand at room temperature for 25 min to form a color, then measure the absorbance A at a wavelength of 560 nm using a 1 cm cuvette.

[0263] 3.1.4.3 Plot a standard curve (straight line) for absorbance A against guaiacol concentration B (μg / mL), as shown below. Figure 9 As shown.

[0264] 3.2 Determination of carbonyl compound content

[0265] 3.2.1 Reagents and Materials

[0266] 3.2.1.1 Preparation of potassium hydroxide solution: 0.1 mol / L.

[0267] 3.2.1.2 Preparation of hydroxylamine hydrochloride solution: 0.5 mol / L solution (storage period not exceeding two weeks). Weigh 40 g of hydroxylamine hydrochloride, dissolve in 200 mL of water, then dilute to 1000 mL. Adjust the pH to 3 with hydrochloric acid or potassium hydroxide solution (close to the pH of the sample, measured with a pH meter). The test results are shown in Table 4.

[0268] 3.2.2 Instruments and Equipment

[0269] 3.2.2.1 pH meter

[0270] 3.2.2.2 Magnetic stirrer.

[0271] 3.2.3 Analysis Steps

[0272] 3.2.3.1 Blank Test: Pipette 25 mL of hydroxylamine hydrochloride solution into a ground-glass stoppered conical flask, stopper the flask, and let it stand for 2 hours. Use 100 mL of...

[0273] After diluting with distilled water, titrate with 0.1 mol / L potassium hydroxide solution to the endpoint, pH = 4.0.

[0274] 3.2.3.2 Sample titration: Accurately pipette 2 mL of sample into a ground glass conical flask and repeat the operation in 3.2.3.1.

[0275] Table 6: pH meter test results

[0276] name PH1 KOH / ml PH2 Hydroxylamine hydrochloride 3.94 0.2 4.00 Pine powder 3.07 7.4 4.00 Rosewood powder 3.10 6.8 4.00 Ebony powder 3.48 3.1 4.00 Bamboo Powder 3.06 8.7 4.00 Eucalyptus tree powder 2.92 12 4.00 Coconut shell powder 3.12 7.2 4.00

[0277] 3.2.4 Results calculation, as shown in Table 7.

[0278] The carbonyl compound content ρ2 (expressed as heptanal), in grams per 100 milliliters (g / 100mL), is calculated according to formula (1):

[0279]

[0280] In the formula:

[0281] The relative molecular mass of M-heptanal is M = 114.18 g / mol;

[0282] c - Concentration of potassium hydroxide solution, in moles per liter (mol / L);

[0283] V - Volume of potassium hydroxide solution consumed in the titration of the sample, in milliliters (mL); V0 - Volume of potassium hydroxide solution consumed in the blank titration, in milliliters (mL); 20 - Conversion factor.

[0284] Table 7: Carbonyl compound content ρ2

[0285]

[0286]

[0287] The relative error of parallel test results is no greater than 1%.

[0288] 4. Experimental Results and Discussion

[0289] The pyrolysis condensate was obtained through experiments, such as Figure 10 As shown, from left to right, the pyrolysis condensate of pine wood, ebony, rosewood, bamboo powder, coconut shell, and eucalyptus is respectively. It can be seen that the refined pyrolysis condensate is clear in color and has fewer impurities.

[0290] 5. Pine wood pyrolysis condensate, ebony pyrolysis condensate, rosewood pyrolysis condensate and bamboo powder pyrolysis condensate were selected as representatives to impregnate bamboo strips respectively, and the changes in total volatile matter, antibacterial activity and polycyclic aromatic hydrocarbons were observed.

[0291] The effects of pine pyrolysis condensate on bamboo units during the 6-day impregnation process showed changes in TV (Total Volatile Matter), AN (Antimicrobial Activity), and PC (Polycyclic Aromatic Hydrocarbons) as follows: Figure 11 As shown;

[0292] The effects of ebony pyrolysis condensate on bamboo units during the 6-day impregnation process showed changes in TV (Total Volatile Matter), AN (Antimicrobial Activity), and PC (Polycyclic Aromatic Hydrocarbons) as follows: Figure 12 As shown;

[0293] The effects of pyrolysis condensate on bamboo units during the 6-day impregnation process of Huanghuali wood units on TV (Total Volatile Matter), AN (Antimicrobial Activity), and PC (Polycyclic Aromatic Hydrocarbons) are as follows: Figure 13 As shown;

[0294] The effects of bamboo powder pyrolysis condensate on bamboo units during the 6-day impregnation process showed changes in TV (Total Volatile Matter), AN (Antimicrobial Activity), and PC (Polycyclic Aromatic Hydrocarbons) as follows: Figure 14 As shown.

[0295] The results showed that bamboo strips treated with pyrolysis condensate from pine, ebony, rosewood, and bamboo powder exhibited the following changes over time: The TV (transformation volume) indicated that the bamboo strips maintained good stability over 6 days, suggesting that the treated bamboo strips possessed strong and lasting flavor. The AN (antinal osmotic pressure) change showed that the pyrolysis condensate inhibited the germination of mold spores on the bamboo strips, demonstrating broad-spectrum antifungal and antibacterial activity and good antibacterial properties. The PC (polycyclic aromatic hydrocarbon) change indicated that the pyrolysis condensate effectively reduced and slowed the formation of harmful polycyclic aromatic hydrocarbons. The pyrolysis condensate, after penetrating the bamboo, created a uniform smoky flavor and aesthetically pleasing color, enhancing the flavor and color of the bamboo and increasing its added value. The treatment effect, in descending order, was: rosewood pyrolysis condensate > ebony pyrolysis condensate > bamboo powder pyrolysis condensate > pine pyrolysis condensate.

[0296] like Figure 15 The integrated device for preparing pyrolysis condensate and treating bamboo products for food contact, as shown, includes an oscillation adjustment mechanism 100. A clamping adjustment mechanism 200 is provided at the oscillation end of the oscillation adjustment mechanism, and an impregnation mechanism 300 is provided below the clamping adjustment mechanism. The clamping adjustment mechanism is internally adjustable relative to the impregnation mechanism. The impregnation mechanism is adjusted by means of... Figure 21 The guide tube 301 shown is connected to the pyrolysis condensate preparation mechanism 400.

[0297] The oscillation adjustment mechanism includes a support frame 101, and the end of the support frame away from the immersion mechanism is provided with a... Figure 19 The pneumatic cylinder 102 shown has a hollow mounting box 103 at its piston end. The end of the hollow mounting box away from the pneumatic cylinder is open. Inside the hollow mounting box is a sliding rod 104, and a sliding slider 105 slides on the sliding rod. A clamping and adjusting mechanism is mounted on the sliding slider. A centrifugal motor 106 is mounted on the hollow mounting box, and the drive end of the centrifugal motor has... Figure 18 The centrifugal cam 107 shown has a swing shaft 108 at its cam position, a swing connecting rod 109 rotatably mounted on the swing shaft, and a connecting rod 110 rotatably mounted at the end of the swing connecting rod away from the centrifugal motor. The connecting rod is connected to the sliding slider.

[0298] The clamping adjustment mechanism includes, for example: Figure 23The hollow box 201 shown is located at the oscillation end of the oscillation adjustment mechanism. The end of the hollow box away from the oscillation adjustment mechanism is open. A main threaded screw 202 is rotatably mounted inside the hollow box. A set of main threaded sliders 203 with opposite threads are threaded onto the main threaded screw. A main threaded motor 204 is mounted on the hollow box, and the drive end of the main threaded motor is connected to one end of the main threaded screw. A pushing cavity 205 is located inside the main threaded sliders. The end of the pushing cavity away from the oscillation adjustment mechanism is open. Rotating within the pushing cavity is a... Figure 24 The auxiliary threaded screw 206 shown has a set of auxiliary threaded sliders 207 with opposite threads connected to it. An auxiliary threaded motor 208 is mounted on the main threaded slider, and the drive end of the auxiliary threaded motor is connected to one end of the auxiliary threaded screw. The direction of the auxiliary threaded screw is perpendicular to the direction of the main threaded screw. A positioning frame 209 is provided on the auxiliary threaded slider, and a limiting post 210 is provided on the positioning frame. A pressure slider 211 is slidably mounted on the limiting post, and a device such as... is connected to the pressure slider. Figure 25 The limiting spring 212 shown has its end away from the pressure slider connected to the positioning frame. At least one swing rod 213 is oscillating on the pressure slider, the swing direction of the swing rod being the same as the movement direction of the pressure slider. The end of the swing rod away from the pressure slider has a [feature / feature]. Figure 26 The mounting bracket 214 shown has multiple rolling shafts 215 arranged side by side. The pressure slider has multiple resistance plates 216, each corresponding to a specific rolling shaft. A pressure spring 217, capable of telescopic movement, is connected to each resistance plate, with the end of the spring furthest from the resistance plate connected to the mounting bracket. A hollow box is mounted on the sliding slider. The hollow shape of the hollow box matches the external shape of the main threaded slider. A rubber roller 218 is fitted onto each rolling shaft. The mounting bracket has multiple rolling motors 219, each corresponding to a specific rolling shaft, with the drive end of the rolling motor connected to the end of the corresponding rolling shaft. A limiting block 220 is provided at the end of the limiting post near the secondary threaded slider, allowing the pressure slider to be separated and engaged. The limiting post has a polygonal structure.

[0299] Impregnation mechanisms include, for example Figure 17 The impregnation tank 302 shown has a clamping adjustment mechanism that allows for adjustable height relative to the interior of the impregnation tank. A liquid inlet 303 is located on the side wall at the bottom of the impregnation tank, connected to a guide pipe. A one-way valve is installed at the liquid inlet, and a liquid pump 305 is located between the one-way valve and the guide pipe at the liquid inlet. The end of the guide pipe furthest from the impregnation tank is connected to the bottom of the pyrolysis condensate preparation mechanism. A controller 306 is installed on the outer wall of the impregnation tank.

[0300] The pyrolysis condensate preparation mechanism includes a support 401, a weighing pan 402 mounted on the support, a mounting plate 403 mounted on the weighing pan, and a detachable, sealed device on the mounting plate. Figure 20The preparation barrel 404 shown has its bottom connected to the interior of the impregnation tank via a guide tube; the outer wall of the preparation barrel is fitted with a sleeve as shown in the image. Figure 16 The cooling sleeve 405 shown has a temperature-controlled heating rod 406 inside the preparation body; the bottom of the preparation body and the mounting plate are both provided with interconnecting threaded holes 407, and the threaded holes are internally threaded with... Figure 22 The filter disc 408 is shown. An internally threaded ring 409 is provided on the mounting disc, and an externally threaded ring 410 is provided on the preparation tank body. The externally threaded ring and the internally threaded ring are sealed together. The bottom of the preparation tank body has a conical structure. An exhaust pipe 411 is connected to the upper part of the preparation tank body, and an exhaust valve 412 is provided inside the exhaust pipe. A thermocouple thermometer 413 is provided inside the preparation tank body. A feed inlet 414 is provided at the top of the preparation tank body, and a threaded plug 415 is threaded onto the feed inlet. A liquid valve 416 is provided at the threaded hole at the bottom of the preparation tank body. The guide pipe is inclined from top to bottom from the preparation tank body to the impregnation tank. An inlet pipe 417 is connected to the cooling sleeve, and the end of the inlet pipe away from the cooling sleeve is connected to a refrigeration unit.

[0301] The working principle of this invention is as follows:

[0302] By setting up an oscillation adjustment mechanism 100, controlled mechanical vibration is used to vibrate the bamboo products during the impregnation process, breaking the surface tension of the bamboo and accelerating the penetration of the pyrolysis condensate into the pores of the bamboo fibers. The penetration depth of the pyrolysis condensate is increased to 80% of the bamboo thickness (compared to only 50% in traditional static impregnation). Vibration avoids the local concentration gradient caused by static impregnation, ensuring a uniform distribution of antibacterial components (phenols) and flavor substances (carbonyl compounds). By setting up a clamping adjustment mechanism 200, three-dimensional positioning is achieved, and the adjustable clamp is compatible with different shapes of bamboo tubes, bamboo strips, etc., ensuring that bamboo products of different shapes (bamboo tubes / bamboo strips / bamboo fibers) are stably clamped in the vibration environment. By setting up an impregnation mechanism 30... 0. Bamboo products are impregnated in pyrolysis condensate within the impregnation mechanism, forming an antibacterial film layer within the pores of the bamboo products. This reduces moisture adsorption, thereby minimizing bacterial growth and fully imparting antibacterial properties and a smoky flavor to the bamboo. By incorporating a pyrolysis condensate preparation mechanism 400, a closed-loop technology of "precise pyrolysis - instantaneous condensation - intelligent control" is implemented, achieving efficient, safe, and controllable transformation of the pyrolysis condensate from raw material to finished product. The pneumatic cylinder pushing the hollow mounting box allows for vertical displacement with an accuracy of ±0.1mm, and the impregnation depth can be adjusted according to the bamboo thickness (e.g., 1mm to 10mm). A segmented impregnation method can be used (e.g., first shallowly impregnating 1 / 3 of the thickness, then fully impregnating), allowing the pyrolysis condensate to... The adsorption capacity is significantly improved; the centrifugal motor 106 drives the centrifugal cam 107, converting the rotational motion into the horizontal reciprocating movement of the sliding slider 105 on the sliding rod 104 via the swing shaft 108 and the swing connecting rod 109, thereby realizing the reciprocating vibration of the clamping adjustment mechanism in the impregnation mechanism (frequency adjustable from 20Hz to 50Hz), accelerating the penetration of the pyrolysis condensate into the bamboo fiber pores (increasing the bamboo fiber pore permeability by 35%), and better ensuring the uniform distribution of antibacterial components (phenols) and flavor substances (carbonyl compounds); the mechanical linkage transmission efficiency reaches 92%, which is more energy-efficient than the electromagnetic vibrator; the horizontal reciprocating movement of the sliding slider on the sliding rod maintains an amplitude error of <±5 during vibration. The hollow box 201, with its open design and main threaded screw 202, allows for rapid clamping and positioning of bamboo within a width range of 0mm to 200mm (adjustment time <3 seconds), accommodating different specifications such as bamboo strips and tubes. The secondary threaded screw 206, orthogonal to the main threaded screw, drives two secondary threaded sliders 207 to move in opposite directions via a secondary threaded motor 208, further enabling rapid clamping and positioning of the bamboo, also accommodating different specifications such as bamboo strips and tubes. Simultaneously, the movement of the secondary threaded sliders, driven by the secondary threaded motor, achieves a torque of 0.5 N / cm. 2 ~2N / cm 2The linear pressure adjustment prevents the bamboo from being crushed; the main thread screw and the auxiliary thread screw are independently controlled, so that the width adjustment and pressure application are coordinated, resulting in high operating efficiency; a first pressure sensor is set at the connection between the limit spring 212 and the pressure slider 211; the limit spring is compressed and deformed when the pressure slider contacts the bamboo, and the pressure value is fed back in real time through the deformation (error ±3%), and the auxiliary thread motor is automatically triggered to reverse when the limit is exceeded; the swing rod 213 allows the mounting bracket 214 to adapt to the curvature of the bamboo within a range of ±15°, and with the elastic deformation of the rubber roller 218, the self-adaptive ability is strong; a second pressure sensor is set at the connection between the pressure spring and the mounting bracket. A force sensor and pressure spring continuously apply pressure to the mounting bracket via a resistance plate 216, achieving better adaptive clamping of the bamboo. The hollow box body matches the shape of the main threaded slider (tolerance ±0.05mm) to ensure stable movement. The rubber roller uses a food-grade silicone sleeve with a Shore hardness of 60A, ensuring friction (μ≥0.4) while avoiding scratching the bamboo surface (Ra<1.6μm). The rolling motor 219 drives the rolling shaft 215 (5rpm~10rpm), causing the bamboo to rotate in the impregnation liquid, improving the pyrolysis condensate exchange efficiency by 50% (compared to static clamping). When the second pressure sensor detects a pressure >2.5N / cm... 2When the pressure spring 217 is fully compressed, it triggers the alarm to prevent damage to the bamboo structure. The limit block 220 is made of hard alloy, and the gap between the limit block and the pressure slider is adjustable (0.5mm~2mm) to precisely control the maximum pressing stroke. The polygonal limit post and the inner hole of the pressure slider are non-rotationally fitted to eliminate axial displacement caused by vibration. The lifting and lowering of the clamping adjustment mechanism 200 relative to the impregnation tank 302 can realize segmented impregnation (such as first impregnating 1 / 3 of the depth, and then fully impregnating), so that the pyrolysis condensate penetrates along the longitudinal gradient of the bamboo fiber, improving the penetration uniformity by 40% (the traditional full impregnation method has the problem of excessive adsorption on the surface). The depth of the impregnation tank (≥300mm) is matched with the lifting stroke, and the liquid is controlled during vibration impregnation. The surface fluctuation is controlled within ±2mm to avoid splashing of pyrolysis condensate; the guide tube 301 is directly connected to the bottom of the pyrolysis condensate preparation mechanism to ensure immediate delivery of freshly prepared pyrolysis condensate and avoid oxidation during storage; the inclined guide tube design (15-20° inclination angle) utilizes gravity-assisted flow, stabilizing the liquid flow rate at 0.5L / min-1L / min; the one-way valve, as a backflow prevention guarantee, uses an acid-resistant fluororubber valve core (pH 3-5 resistant) and automatically closes when the liquid pump 305 stops to prevent backflow of impurities in the impregnation tank; the one-way valve and the liquid pump work together to maintain positive pressure in the system, avoiding cavitation phenomena that cause unstable flow; the liquid pump can be a magnetically driven pump (such as the G20-1 type) to achieve precise flow control, with a flow range of 0... Adjustable flow rate from 0.2L / min to 5L / min; the 316 stainless steel pump body and PTFE-coated impeller in the liquid pump are resistant to organic acid corrosion in the pyrolysis condensate, with a continuous operating life of >8000 hours; the controller 306 can achieve integrated management of multiple parameters, enabling real-time monitoring and adjustment; the weighing pan 402 integrates a high-precision sensor (±1g) to monitor the amount of rosewood powder fed and the weight change in the preparation tank 404 in real time, ensuring that the raw materials match the pyrolysis temperature (e.g., 100g of wood powder corresponds to 350℃), reducing the amount of benzo[a]pyrene generated by 22%; a -5℃ ethylene glycol solution (provided by the refrigeration unit) is introduced into the cooling jacket 405, causing the pyrolysis vapor to condense within 2 seconds, improving the recovery rate of flavor substances (guaiacol). >92%; The temperature-controlled heating rod 406 is arranged in three zones (upper / middle / lower) within the preparation tank, and works with the thermocouple thermometer 413 to achieve a temperature difference of ±1.5℃ inside the tank, improving pyrolysis efficiency by 35% (compared to single-point heating); The filter plate 408 can be rotated and disassembled, and can be reused ≥50 times after reverse rinsing (0.3MPa water pressure); The preparation tank 404 is threadedly connected to the mounting plate 403, allowing for quick disassembly of the preparation tank and significantly improving maintenance efficiency; The internal threaded ring 409 and the external threaded ring 410, together with silicone gaskets, can withstand an internal pressure of 0.4MPa (compared to only 0.2MPa for traditional flange structures), preventing pyrolysis vapor leakage (reducing VOCs emissions by 90%); The exhaust valve 412 is used when the pressure is >0.Automatic activation at 35MPa prevents the risk of deflagration; the PID linkage between thermocouple thermometer 413 and temperature-controlled heating rod 406 controls pyrolysis temperature fluctuations within ±1℃, controlling benzo[a]pyrene formation at its source; the liquid valve is controlled by a stepper motor, with a flow rate adjustment accuracy of ±2mL / min, ensuring stable liquid level in the impregnation tank; the guide tube has a 15° inclination angle and its inner wall is made of 316 stainless steel, and gravity-assisted flow reduces liquid pump power consumption by 18%.

Claims

1. A process for preparing pyrolysis condensate, characterized by: Including the following step, (S01) Take an appropriate amount of pyrolysis condensate raw material, and after successively crushing, drying and cooling, obtain constant weight material; (S02) The constant weight material in step (S01) is sieved and placed in the pyrolysis condensate preparation mechanism for sequential pyrolysis and condensation to obtain crude pyrolysis condensate; (S03) The crude pyrolysis condensate from step (S02) is further subjected to low-temperature settling and filtration to obtain refined pyrolysis condensate.

2. The pyrolysis condensate preparation process according to claim 1, characterized in that: The pyrolysis condensate raw material in step (S01) is pine wood powder, rosewood powder, ebony wood powder, bamboo chips, eucalyptus wood powder, or coconut shell powder; the pyrolysis condensate raw material in step (S01) is free from mold and dust; when the drying and cooling cycle continues until the mass difference between the two cycles does not exceed 1g, constant weight material is obtained.

3. The pyrolysis condensate preparation process according to claim 1, characterized in that: The sieving in step (S02) is through an 18-22 mesh sieve; the heating source in the pyrolysis process of step (S02) is a temperature-controlled electric heating rod; the voltage in the pyrolysis process of step (S02) is 220V; the temperature monitoring in the pyrolysis process of step (S02) is completed using a thermocouple thermometer; the pyrolysis endpoint in step (S02) is when no condensate drips; the condensation container in step (S02) is a cooling jacket.

4. The pyrolysis condensate preparation process according to claim 1, characterized in that: The low-temperature settling temperature in step (S03) is -6℃ to -2℃; the low-temperature settling time in step (S03) is 12h to 36h; the filtration in step (S03) is disc filtration; the benzo[a]pyrene content in the purified pyrolysis condensate in step (S03) is detected and controlled to be below 5μg·kg. -1 The total phenol content in the purified pyrolysis condensate of step (S03) is detected and controlled to be between 2 g / L and 5 g / L; the carbonyl compound content in the purified pyrolysis condensate of step (S03) is detected and controlled to be between 1 g / L and 3 g / L.

5. A method for treating food-contact bamboo materials with pyrolysis condensate, characterized by: Take bamboo materials intended for food contact and treat them by immersion, spraying, coating, or fumigation using pyrolysis condensate.

6. The method for treating food contact bamboo with pyrolysis condensate according to claim 5, characterized in that: The impregnation process involves (a01) drying food contact bamboo to a moisture content of less than 12%; (a02) Dilute the pyrolysis condensate with a solvent to obtain an impregnation working solution with a volume fraction of 10% to 15%; (a03) Completely immerse the dried bamboo material from step (a01) in the impregnation solution from step (a02); (a04) Take out the bamboo after the soaking in step (a03), drain the liquid on the surface, and dry it in a forced-air dryer at 55℃~65℃ until constant weight.

7. The method for treating food contact bamboo with pyrolysis condensate according to claim 5, characterized in that: The spray treatment method is as follows: (b01) the pyrolysis condensate is diluted with a solvent to obtain a spray solution with a volume fraction of 10% to 15%; (b02) Place the spray liquid from step (b01) into a sprayer and spray it onto the surface of the bamboo material under a pressure of 0.2MPa to 0.5MPa; (b03) Dry the bamboo material sprayed in step (b02) at 40℃~50℃ for 5min~15min; (b04) Repeat the spraying process in step (b02) and the drying process in step (b03) 2 to 4 times.

8. The method for treating food contact bamboo with pyrolysis condensate according to claim 5, characterized in that: The coating process involves (c01) diluting the pyrolysis condensate with a solvent to obtain a coating solution with a volume fraction of 10% to 15%. (c02) Apply the pyrolysis condensate stock solution or the application solution from step (c01) to the surface of the bamboo using an application tool; (c03) Cur the bamboo material coated in step (c02) at 50℃~60℃ for 1h~2h.

9. The method for treating food contact bamboo with pyrolysis condensate according to claim 5, characterized in that: The fumigation process is as follows: (d01) bamboo is placed in a sealed fumigation chamber and heated to cause the pyrolysis condensate in the sealed fumigation chamber to evaporate. (d02) After the fumigation is completed, force ventilation is applied to the sealed fumigation chamber of step (d01) and the bamboo is removed.

10. An integrated device for preparing pyrolysis condensate and treating bamboo products for food contact, characterized in that: The device includes an oscillation adjustment mechanism (100), an oscillation end of which is provided with a clamping adjustment mechanism (200), and an impregnation mechanism (300) below the clamping adjustment mechanism. The clamping adjustment mechanism is adjusted for height adjustment relative to the interior of the impregnation mechanism. The impregnation mechanism is connected to a pyrolysis condensate preparation mechanism (400) via a guide tube (301). The pyrolysis condensate preparation mechanism includes a support (401), a weighing pan (402) on the support, an installation plate (403) on the weighing pan, and a preparation barrel (404) detachably sealed on the installation plate. The bottom of the preparation barrel is connected to the interior of the impregnation tank via a guide tube. A cooling sleeve (405) is fitted on the outer wall of the preparation barrel, and a temperature-controlled heating rod (406) is provided inside the preparation barrel. The bottom of the preparation barrel and the installation plate are both provided with interconnecting threaded holes (407), and a filter plate (408) is internally threaded into the threaded holes.

Images