Energy-saving block based on straw fermentation bio-based material and preparation method and application thereof

Abstract

The application discloses a kind of bio-based energy-saving block based on straw fermentation and its preparation method and application, belong to agricultural waste resource utilization and agricultural energy-saving technical field.The energy-saving block is pressed by straw treated by high-temperature aerobic-facultative anaerobic fermentation and quicklime, and the quicklime addition amount is 0.75 wt% of the dry weight of fermented straw, the moisture content of finished product is 30% to 50%, pH is greater than or equal to 8.5, the specific surface area is greater than or equal to 11.0 m² / g, and the surface is sprayed with black water-based breathable silicone coating.The application realizes self-gluing of fiber by using natural adhesive material generated by fermentation, without synthetic adhesive;The problem of mildew is solved by double protection of quicklime and coating;The constructed multi-pore structure gives it excellent heat storage performance, and the minimum temperature of greenhouse at night is improved.The application has low cost, is environment-friendly and pollution-free, realizes high-value utilization of straw and double goals of greenhouse energy saving.

Description

Technical Field

[0001] This invention belongs to the field of agricultural waste resource utilization and agricultural energy conservation technology, specifically relating to a bio-based energy-saving block and its preparation method, as well as the application of the energy-saving block in greenhouse heat storage walls. Background Technology

[0002] Although the comprehensive utilization rate of straw has improved, a large amount of straw is still not effectively utilized. Traditional disposal methods such as open burning and landfill not only increase PM2.5 emissions and cause serious air pollution, but also result in a huge waste of carbon resources. Therefore, promoting the high-value and large-scale utilization of straw has become one of the key paths.

[0003] Making straw into biomass substrate or building materials is an important direction for the resource utilization of straw. However, the current technology in this field still faces many bottlenecks in terms of pretreatment cost, environmental protection and product performance: (1) High pretreatment cost and high energy consumption: The main component of straw is lignocellulose, which has a complex composition and dense structure and strong natural resistance to degradation. Before processing into substrate, it usually needs to be physically crushed with high intensity, which consumes a lot of energy. If chemical treatment (such as acid / alkali method) is used, although it can destroy the structure, it is easy to generate secondary pollution and the subsequent waste liquid treatment cost is high. (2) Molding process depends on synthetic chemical adhesives: In order to obtain sufficient mechanical strength, the existing straw molding technology often needs to add 10%-20% synthetic adhesives (such as urea-formaldehyde resin, polyvinyl alcohol, etc.), which not only greatly increases the production cost, but also introduces harmful substances such as formaldehyde, which reduces the biodegradability of the product. In addition, after long-term use or disposal, the fragmented or micronized particles of such products are prone to causing secondary pollution of soil or water. (3) Fermented products have a loose structure and are prone to mold. Although microbial fermentation can effectively degrade straw lignin (the degradation rate can reach 30%-80%), realize the homogenization of straw and improve its processing performance, the existing fermentation process generally has problems such as low strain compatibility, long lignin degradation cycle and complex and uncontrollable fermentation product composition. More importantly, the straw fiber binding force after traditional fermentation is weak, and the products directly formed by mechanical molding have low strength and are easy to loose. Moreover, it is very easy to breed mold and rot in a humid environment, and cannot be used as an independent building material for a long time. (4) Lack of heat storage and temperature regulation function: Most existing straw products are solid or have large pore structure with small specific surface area. They do not have efficient heat storage and heat release capacity, which makes it difficult to meet the urgent need of facility agriculture for nighttime heat preservation.

[0004] In the prior art, Chinese patent document CN 107311562 A discloses a fermented concrete block made of wheat straw and its preparation method. This technology mainly uses fermentation to mix straw as a filler aggregate into the concrete matrix, aiming to solve the problem of soil erosion and play a filling role. However, this technology still has certain limitations when applied to greenhouse heat storage walls: (1) It does not adopt a two-stage fermentation system of "high temperature aerobic-facultative anaerobic" and a self-heating starter microbial agent system, making it difficult to achieve deep softening of straw lignin and effective dissociation of fiber bundles, resulting in limited changes in the physicochemical properties of the straw itself. (2) The strength of the block mainly depends on the cement matrix, and the straw only plays the role of filler aggregate and does not have independent structural support capabilities. (3) It does not construct a nanoscale microporous structure and lacks the temperature regulation function of "high temperature heat storage and low temperature heat release", which cannot meet the energy-saving needs of greenhouses in cold regions.

[0005] Therefore, developing a straw-based energy-saving block that requires no synthetic adhesives, is low-cost, and has excellent heat storage and temperature regulation functions, as well as its preparation process, is one of the technical challenges that urgently need to be solved in the field of agricultural waste resource utilization and facility agriculture energy conservation. Summary of the Invention

[0006] In view of this, the present invention provides a bio-based energy-saving block based on straw fermentation, its preparation method, and its application. By discovering and leveraging the new functions of existing microbial agents (Bacillus polymyxa) under specific processes, a low-cost straw fermentation technology is developed that achieves self-adhesion through fiber winding without the need for synthetic chemical adhesives. This invention transforms waste straw into a bio-based energy-saving block with a multi-microporous structure, excellent heat storage performance, and good water and mildew resistance, replacing traditional high-energy-consuming building materials and achieving the dual goals of high-value utilization of agricultural waste and energy conservation in facility agriculture.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a bio-based energy-saving block, which is made of straw treated with high-temperature aerobic-facultative anaerobic fermentation and quicklime, wherein the amount of quicklime added is 0.75 wt% of the dry weight of the fermented straw, the moisture content of the energy-saving block is 30% to 40%, the pH value of the energy-saving block is ≥8.5, and the interior has a multi-microporous structure formed by intertwined fiber bundles.

[0008] Preferably, the energy-saving block is a cuboid with external dimensions of 40 cm in length, 20 cm in width, and 20 cm in height.

[0009] Preferably, the total pore volume of the multi-microporous structure is ≥0.07 cm³. 3 / g, specific surface area ≥11.0 m² 2 / g.

[0010] Preferably, the total pore volume of the multi-microporous structure is 0.0741 cm³. 3 / g, with a specific surface area of ​​11.62 m². 2 / g.

[0011] Preferably, the surface of the energy-saving block is coated with a black water-based breathable silicone resin coating; the coating allows water vapor to pass through to expel internal moisture, while blocking liquid water penetration, and can undergo a cross-linking reaction with hydroxide ions in quicklime to form stable chemical bonds.

[0012] This invention also discloses a method for preparing the above-mentioned bio-based energy-saving block, comprising the following steps: (1) Crush the straw into straw segments with a length ≤ 8 cm; (2) Prepare self-heating, high-temperature aerobic fermentation substrate; (3) Mix the straw obtained in step (1) with the fungal material obtained in step (2), and add water to adjust the average moisture content of the material to 65% to 70%. Pack the mixture into a plastic tube film with a diameter ≥ 2.0 m and a height ≥ 2.5 m for aerobic fermentation, so that the pile temperature rises to above 55℃ within 2 to 3 days, and the accumulated temperature of above 55℃ reaches 90 to 110℃·d. (4) After the pile enters the facultative anaerobic fermentation stage, continue fermentation at a temperature ≥35℃ until the plastic film bulges and produces biogas. Then stop fermentation, take out the material and air dry it until the moisture content is 43%~48%. (5) Add quicklime, which accounts for 0.75% of the dry weight of the material, to the air-dried material and stir well; (6) The prepared material is filled into a metal frame mold with an inner cavity of 40 cm in length, 20 cm in width and 20 cm in height. It is pressed and formed under a pressure of 15-20 MPa. After demolding, it is air-dried in a cool and ventilated place for 7-15 days to obtain the bio-based energy-saving block.

[0013] Preferably, in step (1), the length of the straw segment is 3 to 8 cm.

[0014] Preferably, in step (2), the self-heating aerobic fermentation substrate is composed of a self-heating aerobic fermentation agent and nutrient additives; the nutrient additives include rice bran, brown sugar, and urea; based on processing 1 ton of dry straw, the amount of fermentation substrate added is: 1 kg of self-heating aerobic fermentation agent, 30 kg of rice bran, 1 kg of brown sugar, and 2.5 kg of urea; the self-heating aerobic fermentation agent contains a concentration of not less than 1.0 × 10⁻⁶. 9The cfu / g Paenibacillus polymyxa is registered with the China General Microbiological Culture Collection Center, preservation number CGMCC No: 20494.

[0015] Preferably, in step (3), the aerobic fermentation stage lasts for 7 to 10 days, during which the temperature at the center of the pile is maintained at 55 to 70°C until the accumulated daily temperature above 55°C reaches 100 to 110°C·d.

[0016] The present invention also discloses the application of the above-mentioned bio-based energy-saving blocks in greenhouse heat storage walls. The bio-based energy-saving blocks are stacked tightly against the back wall of the greenhouse to the back slope to form a heat storage wall, and a black water-based breathable silicone resin coating is sprayed on its surface to absorb solar radiation heat during the day and slowly release heat at night. At the same time, the coating enables the internal moisture to be discharged and the external moisture to be blocked.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Significantly increases greenhouse nighttime temperature: This invention successfully constructs a nanoscale multi-microporous structure inside straw through a two-stage fermentation process of "high-temperature aerobic-facultative anaerobic". For example Figure 1 As shown, after 80 days of fermentation, the specific surface area of ​​a single straw increased from 0.83 m². 2 / g increased to 2.38 m 2 / g, total pore volume increased from 0.0082 cm³ 3 / g increased to 0.0152 cm 3 / g, with significantly enhanced internal air channels; after further pressing and molding, due to increased density and fiber reorganization, the specific surface area of ​​the energy-saving block further increased to 11.62 m². 2 / g, with a total pore volume of 0.0741 cm³. 3 / g, the huge specific surface area endows the material with extremely strong heat absorption and release capabilities. Measured data (see...) Figure 3 The results show that in the early morning of winter in cold regions, the average minimum temperature of greenhouses equipped with the energy-saving blocks of this invention is 13.85℃, which is 12.03℃ higher than that of traditional brick-concrete control greenhouses. This temperature difference upgrades the greenhouse planting structure from only being able to produce cold-resistant leafy vegetables to being able to meet the growth needs of solanaceous vegetables, greatly reducing the energy consumption for heating in winter, and the energy-saving effect is extremely obvious.

[0018] (2) Abandoning synthetic chemical adhesives, green and environmentally friendly: This invention abandons the traditional process of adding 10%-20% urea-formaldehyde resin and other synthetic adhesives to straw boards. It utilizes the polysaccharides, monosaccharides, glycerol and fatty acids produced during fermentation, which are rich in viscosity, and combine them with the physical winding of straw fibers to achieve self-adhesion under a pressure of 15~20MPa. This not only reduces the cost of raw materials, but also eliminates the risk of releasing harmful gases such as formaldehyde from the source. The product is green and pollution-free throughout its entire life cycle. After disposal, it can be biodegraded and returned to the soil. It effectively solves the problem of secondary pollution caused by the use of synthetic glue in traditional straw boards, which is in line with the development direction of green building materials.

[0019] (3) Water-resistant and mildew-proof, with a long service life: In view of the characteristics of straw products being prone to moisture absorption and rotting, this invention constructs a dual protection system of "internal alkali and external looseness". In terms of internal antibacterial properties, by adding 0.75% quicklime, the pH value of the base material is maintained above 8.5. Figure 4 Plate colony experiments showed that mold proliferated in samples without lime, while no mold grew in samples with lime; long-term monitoring data ( Figure 2 The results showed that after four years of application in a real greenhouse environment with high humidity, the internal pH value of the energy-saving block remained at an alkaline level of 8.27, continuously inhibiting microbial decomposition. For external protection, the black water-based breathable silicone resin coating sprayed on the surface not only prevents liquid water penetration and swelling but also allows internal moisture to escape. Furthermore, it chemically cross-links with quicklime, further enhancing the adhesion of the protective layer.

[0020] (4) Discovering new functions of existing microbial agents, low cost, controllable process, and easy promotion: This invention discovers and utilizes new functions of existing commercial Bacillus polymyxa (CGMCC No: 20494) under specific process conditions, achieving low-cost and high-efficiency fermentation. Under specific conditions of high moisture content (65~70%) and large pile size (diameter ≥2.0 m, height ≥2.5 m), the microbial agent can rapidly heat up within 3 days without the need to add expensive special enzyme preparations or external heat sources. At the same time, the requirements for straw crushing particle size are relaxed (≤8 cm), significantly reducing the energy consumption of physical crushing. The overall process is simple and highly controllable, making it very suitable for the large-scale on-site conversion and promotion of agricultural waste, with significant economic and social benefits. Attached Figure Description

[0021] Figure 1 The figures are comparative diagrams of the structural features of individual straws under different treatments in the embodiments of the present invention; wherein, (a) is a bar chart of the change in specific surface area, (b) is a bar chart of the change in total pore volume, and (c) is a bar chart of the change in average pore diameter. Figure 2 This is a graph showing the pH value variation of the bio-based energy-saving block under different application years in an embodiment of the present invention. Figure 3 This is a comparison curve of greenhouse temperature under different treatments in the embodiments of the present invention; wherein, the blue curve represents the heat storage greenhouse equipped with the bio-based energy-saving block of the present invention, and the red curve represents the traditional brick-concrete control greenhouse. Figure 4 The above are comparison images of plate colony performance under different treatments in the embodiments of the present invention; wherein, (a) is the sample without quicklime (before addition), and (b) is the sample with quicklime added (after addition). Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0024] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0025] This invention discloses a bio-based energy-saving block, which is made of straw treated with high-temperature aerobic-facultative anaerobic fermentation and quicklime, wherein the amount of quicklime added is 0.75 wt% of the dry weight of the fermented straw, the moisture content of the energy-saving block is 30% to 40%, the pH value of the energy-saving block is ≥8.5, and the interior has a multi-microporous structure formed by intertwined fiber bundles.

[0026] The aforementioned energy-saving block is a cuboid with dimensions of 40 cm in length, 20 cm in width, and 20 cm in height; the total pore volume of the multi-microporous structure is ≥0.07 cm³. 3 / g, specific surface area ≥11.0 m² 2 / g; the total pore volume of the optimal microporous structure is 0.0741 cm³. 3 / g, with a specific surface area of ​​11.62 m². 2 / g.

[0027] The energy-saving block is coated with a black water-based breathable silicone resin coating; the coating allows water vapor to pass through to expel internal moisture, while blocking liquid water penetration, and can undergo a cross-linking reaction with hydroxide ions in quicklime to form stable chemical bonds.

[0028] This invention also discloses a method for preparing the above-mentioned bio-based energy-saving block, comprising the following steps: (1) Crush the straw into straw segments with a length of ≤8 cm (preferably 3-8 cm); (2) Preparation of self-heating high-temperature aerobic fermentation substrate; wherein: the self-heating high-temperature aerobic fermentation substrate is composed of a self-heating aerobic fermentation agent and nutrient additives; the nutrient additives include rice bran, brown sugar and urea; based on the treatment of 1 ton of dry straw, the amount of fermentation substrate added is: 1 kg of self-heating aerobic fermentation agent, 30 kg of rice bran, 1 kg of brown sugar and 2.5 kg of urea; the concentration of the self-heating aerobic fermentation agent is not less than 1.0 × 10⁻⁶. 9 The cfu / g Paenibacillus polymyxa was deposited on August 6, 2020, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No: 20494. The address of the depository is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0029] (3) Mix the straw obtained in step (1) with the fungal material obtained in step (2), and add water to adjust the average moisture content of the material to 65% to 70%. Pack the mixture into a plastic tube film with a diameter ≥ 2.0 m and a height ≥ 2.5 m for aerobic fermentation, so that the pile temperature rises to above 55℃ within 2 to 3 days, and the accumulated temperature of above 55℃ reaches 90 to 110℃·d. The aerobic fermentation stage lasts for 7 to 10 days, during which the temperature at the center of the pile is maintained at 55 to 70°C until the accumulated daily temperature above 55°C reaches 100 to 110°C·d.

[0030] The present invention also discloses the application of the above-mentioned bio-based energy-saving blocks in greenhouse heat storage walls. The bio-based energy-saving blocks are stacked tightly against the back wall of the greenhouse to the back slope to form a heat storage wall, and a black water-based breathable silicone resin coating is sprayed on its surface to absorb solar radiation heat during the day and slowly release heat at night. At the same time, the coating enables the internal moisture to be discharged and the external moisture to be blocked.

[0031] Example 1 (1) Mold preparation: Make a rectangular metal plate frame mold with an inner cavity of 40 cm in length, 20 cm in width, and 20 cm in height.

[0032] (2) Straw pretreatment: Select dry corn stalks and use a shredder to break them into stalk segments of 3–8 cm in length. This length range balances the contact area between microorganisms and the porosity of the pile, which is beneficial for subsequent fermentation and the fiber winding strength after molding.

[0033] (3) Preparation of substrate: Weigh out 1 kg of heat-start aerobic fermentation inoculum (containing Bacillus polymyxa CGMCC No: 20494, concentration 1.0 × 10⁻⁶). 9 The mixture (cfu / g) is thoroughly mixed with nutrient supplements (30 kg rice bran, 1 kg brown sugar, and 2.5 kg urea) to prepare a self-heating, high-temperature aerobic fermentation substrate. This formulation is designed to process 1 ton of dry straw.

[0034] (4) Aerobic fermentation stage: Mix 1 ton of pretreated straw with the above-mentioned substrate, add water and stir to make the average moisture content of the material reach 65% to 70% (higher than the moisture content of conventional aerobic fermentation, so as to promote lignin softening); then put the mixture into a plastic tube film with a diameter of 2.0 m and a height of 2.5 m, and pile it up naturally to form a pile.

[0035] Under the heat generated by the inoculant, the temperature of the straw pile rapidly rises to above 55°C within two days. Fermentation is maintained for nine days, during which the temperature at the center of the pile remains around 60°C, and the accumulated daily temperature above 55°C reaches 100°C·d. This process achieves the softening of straw lignin and the conversion of hemicellulose into organic acids and amino acids.

[0036] (5) Facultative anaerobic fermentation stage: After aerobic fermentation, the inside of the plastic film becomes oxygen-deficient, entering a facultative anaerobic fermentation state. The temperature is maintained above 35℃ using sunlight or indoor insulation. After approximately 8 days of fermentation, the plastic film is observed to bulge and biogas is produced, indicating that the polysaccharides and other viscous substances have begun to decompose and produce gas. At this point, fermentation is immediately stopped to preserve the effective binding components. The film is then opened, and the material is spread out to air dry until the moisture content drops to 45%.

[0037] (6) Material preparation and pelletizing: Add lime: Add quicklime powder, which accounts for 0.75% of the dry weight of the material, to the air-dried material and mix it evenly with a mixer; this step raises the pH value of the material to above 8.5, which plays a role in sterilization and preservation.

[0038] Pressure molding: The material is filled into a metal frame mold, and a hydraulic press is used to apply a pressure of 18MPa (within the range of 15 to 20MPa). After holding the pressure, the material is demolded. Pressure control is crucial. Too low a pressure will cause the material to become loose, while too high a pressure will damage the microporous structure and affect heat storage.

[0039] Air drying: Stack the shaped straw blocks in a cool, ventilated place and air dry naturally for 10 days (within the range of 7 to 15 days) to obtain the final product.

[0040] Finished product testing: The moisture content of the finished product was measured to be 39% (within the range of 30%–40%), and the pH value was 8.9. Analyzed using a BSD-660MA6M analyzer, its specific surface area was 11.62 m² / g, and its total pore volume was 0.0741 cm³ / g. (7) Surface treatment and application: The manufactured energy-saving blocks are stacked tightly against the back wall of the greenhouse up to the back slope to form a heat-storing wall. A black water-based breathable silicone resin coating is evenly sprayed onto the wall surface. After the coating dries, it forms a protective film that is both waterproof and breathable, and it undergoes a cross-linking reaction with the calcium hydroxide inside the blocks to enhance the bonding strength. The black surface also helps to absorb solar radiation.

[0041] Comparative Example 1 This comparative example is prepared from bio-based blocks without the addition of quicklime.

[0042] (1) Straw pretreatment and fermentation: Same as steps 2 to 5 of Example 1. That is, select corn straw, crush it into 3-8cm pieces, use Bacillus polymyxa as inoculum for high-temperature aerobic and facultative anaerobic fermentation until biogas is produced, and then air dry it to a moisture content of 45%.

[0043] (2) Material preparation: Do not add quicklime to the air-dried fermented material and mix directly; at this time the pH value of the material is about 6.5~7.0 (neutral or weakly acidic).

[0044] (3) Press molding: Fill the material without lime into a metal frame mold with a length of 40 cm × width of 20 cm × height of 20 cm, apply 18 MPa pressure to press and mold, and after demolding, air dry in a cool and ventilated place for 10 days.

[0045] (4) Surface treatment: Same as in Example 1, a black water-based breathable silicone resin coating is sprayed onto the surface of the block. Straw base material blocks without added quicklime are obtained.

[0046] Comparative Example 2: This comparative example is prepared from unfermented straw boards with added synthetic adhesives.

[0047] (1) Straw pretreatment: Select dry corn stalks and crush them into straw segments with a length of ≤8 cm; do not carry out any microbial fermentation treatment and use raw straw directly.

[0048] (2) Adhesive preparation: No biological substrate is used. Weigh commercially available urea-formaldehyde resin glue (solid content 50%) as adhesive and add it at 15% of the dry weight of straw (in line with the traditional process range of 10%~20%).

[0049] (3) Mixing and conditioning: Mix the raw straw segments with urea-formaldehyde resin glue evenly, and add water to adjust the moisture content to 12%-15% (the moisture content of traditional artificial boards is much lower than the 65%~70% of this invention).

[0050] (4) Press molding: The mixture is filled into a metal frame mold with a length of 40 cm × width of 20 cm × height of 20 cm, and 18 MPa pressure is applied to press it into shape.

[0051] (5) Curing and drying: After demolding, place it in an oven and dry it at 80°C until the moisture content is below 10% to cure the urea-formaldehyde resin.

[0052] (6) Surface treatment: Same as in Example 1, a black water-based breathable silicone resin coating is sprayed on the board surface to obtain a straw board bonded by traditional synthetic adhesive.

[0053] Performance test comparison: 1. Testing of thermal storage physical characteristics: A BSD-660M A6M high-performance specific surface area and micropore analyzer was used (degassing conditions: 80℃, 120min; leveling conditions: 0.1%Pr / 120s; low-pressure gas injection: standard quantitative 0.5cm). 3 The specific surface area, total pore volume, and average pore diameter of the energy-saving block prepared in Example 1 and the ordinary straw block in Comparative Example 2 were tested. Figure 1 As shown.

[0054] As can be seen from the figure, after fermentation, the specific surface area of ​​the straw increased from 0.83 m². 2 / g increased to 2.38 m 2 / g, the total pore volume increased from 0.0082cm3 / g to 0.0152cm3 / g, while its average pore diameter decreased from 39.4658 nm before fermentation to 25.5055 nm; this indicates that after fermentation treatment, the internal air channels and specific surface area adsorption area of ​​the straw in Example 1 were significantly enhanced, which is conducive to a significant increase in the heat storage capacity of the material itself, and thus achieves a qualitative improvement in its heat storage and release capacity.

[0055] 2. Corrosion resistance testing: like Figure 2 As shown in the figure, the energy-saving block prepared by the method in Example 1 was continuously monitored in a greenhouse environment for 4 years. It can be seen from the figure that as the application period increased, the average pH of the energy-saving block gradually decreased from 8.90 to 8.27, and it was always in an alkaline environment, which effectively inhibited the growth of microorganisms.

[0056] like Figure 4As shown in the figure, the addition of quicklime has an inhibitory effect on straw mold. It can be seen from the figure that the control sample without quicklime grew a large number of mold colonies; while the sample of Example 1 (with quicklime) had a clean plate with no mold growth. This shows that the addition of 0.75% quicklime has a significant anti-mold effect.

[0057] 3. Actual measurement of greenhouse insulation effect: Two identical solar greenhouses were constructed in a high-altitude, cold region. One greenhouse had its back wall covered with energy-saving blocks as described in Example 1 (a heat storage greenhouse), while the other had a traditional brick-concrete wall (control). A Jingchuang automatic temperature and humidity recorder was used to continuously monitor the temperature at 5:30 AM in winter (the lowest temperature period of the day).

[0058] like Figure 3 As shown, during the entire test period (January 1st to February 26th), the average minimum temperature in the heat storage greenhouse was 13.85℃, while the control greenhouse only reached 1.82℃. The temperature difference was as high as 12.03℃. This indicates that installing this invention significantly increased the nighttime temperature of the greenhouse, enabling it to meet the growth requirements of solanaceous vegetables, while the control greenhouse could only grow cold-resistant leafy vegetables, verifying the excellent heat storage and release effect of this invention.

[0059] The present invention provides a detailed description of an energy-saving bio-based material block based on straw fermentation, its preparation method, and its application. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these examples are merely for the purpose of helping to understand the method and core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A bio-based energy-saving block, characterized in that, The energy-saving block is made by pressing straw that has undergone high-temperature aerobic-facultative anaerobic fermentation with quicklime. The amount of quicklime added is 0.75 wt% of the dry weight of the fermented straw. The moisture content of the energy-saving block is 30%–40%, and the pH value of the energy-saving block is ≥ 8.5, with an internal microporous structure formed by intertwined fiber bundles.

2. The bio-based energy-saving block according to claim 1, characterized in that, The energy-saving block is a cuboid with external dimensions of 40 cm in length, 20 cm in width, and 20 cm in height.

3. The bio-based energy-saving block according to claim 1, characterized in that, The total pore volume of the multi-microporous structure is ≥0.07 cm³. 3 / g, specific surface area ≥11.0 m² 2 / g.

4. The bio-based energy-saving block according to claim 3, characterized in that, The total pore volume of the microporous structure is 0.0741 cm³. 3 / g, with a specific surface area of ​​11.62 m². 2 / g.

5. The bio-based energy-saving block according to claim 1, characterized in that, The energy-saving block is coated with a black water-based breathable silicone resin coating. The coating allows water vapor to pass through to expel internal moisture, while blocking liquid water penetration, and can cross-link with hydroxide ions in quicklime to form stable chemical bonds.

6. A method for preparing the bio-based energy-saving block as described in claim 1, characterized in that, Includes the following steps: (1) Crush the straw into straw segments with a length ≤ 8 cm; (2) Prepare self-heating, high-temperature aerobic fermentation substrate; (3) Mix the straw obtained in step (1) with the fungal material obtained in step (2), and add water to adjust the average moisture content of the material to 65% to 70%. Pack the mixture into a plastic tube film with a diameter ≥ 2.0 m and a height ≥ 2.5 m for aerobic fermentation, so that the pile temperature rises to above 55℃ within 2 to 3 days, and the accumulated temperature of above 55℃ reaches 90 to 110℃·d. (4) After the pile enters the facultative anaerobic fermentation stage, continue fermentation at a temperature ≥35℃ until the plastic film bulges and produces biogas. Then stop fermentation, take out the material and air dry it until the moisture content is 43%~48%. (5) Add quicklime, which accounts for 0.75% of the dry weight of the material, to the air-dried material and stir well; (6) The prepared material is filled into a metal frame mold with an inner cavity of 40 cm in length, 20 cm in width and 20 cm in height. It is pressed and formed under a pressure of 15-20 MPa. After demolding, it is air-dried in a cool and ventilated place for 7-15 days to obtain the bio-based energy-saving block.

7. The preparation method according to claim 6, characterized in that, In step (1), the length of the straw segment is 3 to 8 cm.

8. The preparation method according to claim 6, characterized in that, In step (2), the self-heating aerobic fermentation substrate is composed of a self-heating aerobic fermentation agent and nutrient additives; the nutrient additives include rice bran, brown sugar, and urea; based on processing 1 ton of dry straw, the amount of fermentation substrate added is: 1 kg of self-heating aerobic fermentation agent, 30 kg of rice bran, 1 kg of brown sugar, and 2.5 kg of urea; the self-heating aerobic fermentation agent contains a concentration of not less than 1.0 × 10⁻⁶. 9 cfu / g of Bacillus polymyxa, wherein the Bacillus polymyxa is registered with the China General Microbiological Culture Collection Center, preservation number CGMCC No: 20494.

9. The preparation method according to claim 6, characterized in that, In step (3), the aerobic fermentation stage lasts for 7 to 10 days, during which the temperature at the center of the pile is maintained at 55 to 70°C until the accumulated daily temperature above 55°C reaches 100 to 110°C·d.

10. The application of bio-based energy-saving blocks as described in any one of claims 1 to 5 in greenhouse heat storage walls, characterized in that, The bio-based energy-saving blocks are stacked tightly against the back wall of the greenhouse to form a heat storage wall. A black water-based breathable silicone resin coating is sprayed on its surface to absorb solar radiation heat during the day and slowly release heat at night. At the same time, the coating enables internal moisture to be discharged and external moisture to be blocked.

Images