Disclosure of Invention
The invention aims to solve the technical problem of providing the biochar processed by in-situ evaporation, which is prepared from agricultural and forestry wastes such as straws and stalks and has good adsorption performance and stable quality, aiming at the defects of the biochar material and the preparation technology in the prior art.
The invention also provides a preparation method of the biochar processed by in-situ evaporation, which is used for preparing the biochar with high adsorption performance from agricultural and forestry wastes such as straws, reeds, wood and the like. The preparation method realizes effective utilization of the agricultural and forestry wastes, and has the advantages of simple preparation process, high carbonization degree of the obtained biochar finished product and good adsorption performance.
The technical problem to be solved by the invention is to provide a device for realizing the preparation method.
The purpose of the invention is realized by the following technical scheme:
an in-situ evaporation processed biochar is prepared from the following components: the vegetable fiber and dextrin composite material comprises vegetable fiber, paraffin, dextrin and white sugar, wherein the mass of the paraffin is 1-10% of that of the vegetable fiber, the mass of the dextrin is 1-10% of that of the vegetable fiber, and the mass of the white sugar is 1-10% of that of the vegetable fiber.
Preferably, the mass of the paraffin is 3% of the mass of the plant fiber, the mass of the dextrin is 3% of the mass of the plant fiber, and the mass of the white sugar is 3% of the mass of the plant fiber.
The invention is beneficial to the shaping in the plant fiber pressing process by adding the paraffin, and simultaneously, in the carbonization process, a large number of holes are formed due to the discharge of the paraffin, thus being beneficial to improving the adsorption capacity of the product; by adding the white sugar and the dextrin, the bonding property of the white sugar and the dextrin can promote the fiber to be agglomerated, the strength of the biochar is improved, meanwhile, the capacity of the product for adsorbing ions can be improved after the white sugar is carbonized, and the adsorption capacity can be improved after the dextrin is carbonized.
Further, the plant fiber comprises one or more of straw, stalk, reed and wood; the diameter of the plant fiber is less than or equal to 2mm, and the length of the plant fiber is less than or equal to 50 mm; the water content is 8-15%.
The invention also provides a preparation method of the biochar subjected to in-situ evaporation processing, which comprises the following steps:
s1, crushing plant fibers and then drying;
s2, uniformly mixing the plant fibers treated in the step 1 with paraffin, dextrin and white sugar, and pressing into fiber blocks, wherein the density of the fiber blocks is 0.5-1.2 Kg/m3;
And S3, putting the fiber block prepared in the step S2 into an in-situ evaporation carbonization device for carbonization treatment to obtain a biochar product.
Preferably, the plant fiber in step S1 is one or more of straw, stalk, reed and wood.
According to the invention, loose and soft straw, reed, wood and other plant fibers are used as raw materials, and the raw materials are easily processed into porous biochar with high adsorption performance, so that the effective utilization of agricultural and forestry wastes is realized, and the cost of the biochar is reduced.
Further, in step S1, the diameter of the crushed plant fiber is less than or equal to 2mm, and the length is less than or equal to 50 mm.
Preferably, the plant fiber is crushed in step S1 to have a diameter of 1mm and a length of 20 mm.
Further, the drying mode of the plant fiber is drying, and the water content of the dried plant fiber is 8-15%.
Preferably, the water content of the dried plant fiber is 10%.
In the preparation process of the biochar, the density of the fiber material block is strictly controlled to be 0.5-1.2 kg/m3In the meantime. If the density is too low, the blocks may be scattered, and the blocked charcoal cannot be obtained, and if the density is too high, the holes of the charcoal may be too few, which affects the adsorption effect.
Further, the technological parameters of the plant fiber block in the carbonization device for carbonization treatment are as follows: the vacuum rate is more than 85%, the temperature is 150-400 ℃, and the time is 2-24 hours.
Preferably, the carbonization treatment temperature is 250 ℃.
The invention also provides an in-situ evaporation carbonization device for realizing the preparation method, which comprises a base and an upper cover detachably connected with the base, wherein the base is of a cavity structure with an opening, and the upper cover is arranged at the opening of the base; the cavity structure is used for placing the plant fiber blocks; a bottom supporting plate is arranged in the cavity, a through hole is formed in the bottom supporting plate, and supporting legs are arranged at the lower part of the bottom supporting plate; the upper cover is provided with a vacuum-pumping system and an exhaust device, the base is provided with a heating device, and the bottom of the base is provided with a sewage draining outlet.
In the carbonization process, gases such as oxygen and the like in the carbonization device are firstly pumped out through the vacuum pumping system, so that an anaerobic environment is caused, and the plant fiber block is prevented from burning in the carbonization process. And then carbonizing the plant fiber block at high temperature to evaporate paraffin and water, combining hydrogen atoms and oxygen atoms in the fiber, dextrin and white sugar into water to form water vapor, so that a large number of holes are formed, and the water vapor and capillary tubes after fiber carbonization act synergistically to have good adsorption capacity on ions, solid residues and the like in liquid, so that a charcoal product with high adsorption capacity is obtained.
Compared with the prior art, the invention has the beneficial effects that:
the biochar provided by the invention has good adsorption performance and stable performance, can be effectively applied to the fields of sewage purification, human and animal excrement treatment and the like, and has extremely high popularization value. The adsorbed biochar can be used as an organic fertilizer for ecological organic agriculture after being dried and deodorized.
The invention takes agricultural and forestry waste as main raw material and paraffin. After the white sugar and the dextrin are mixed and compressed into blocks, the blocks are carbonized under the action of an in-situ evaporation processing carbonization device, the agricultural and forestry waste is recycled, and the preparation process is simple.
The invention uses the in-situ evaporation carbonization device to process and carbonize the plant fiber, has simple process and high production efficiency, and has no adverse effect on the environment.
Detailed Description
The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated. Unless otherwise indicated, reagents and materials used in the following examples are commercially available.
Example 1
As shown in fig. 1 and 2, this embodiment provides an in-situ evaporation carbonization apparatus, which can be used for preparing biochar. The carbonization device comprises a base 3 and an upper cover 4, wherein the base 3 and the upper cover 4 are detachably connected and comprise flange connection and spiral connection. In the present embodiment, the base 3 and the upper cover 4 are flange-connected.
The base 3 is a cavity structure with an opening, the upper cover 4 is arranged at the opening of the base, and the cavity structure is used for placing the plant fiber block 7. A bottom supporting plate 1 is arranged in the cavity of the cavity structure, a through hole is arranged on the bottom supporting plate 1, and supporting legs are arranged on the lower portion of the bottom supporting plate 1. The bottom supporting plate 1 can timely separate liquid generated in the carbonization process from the plant fiber block 7, and the carbonization process is prevented from being influenced by too much liquid. The bottom of the base 3 is provided with a drain outlet 8 for discharging the liquid generated in the carbonization process, which is beneficial to cleaning the carbonization device.
The base outside is equipped with heating device 2, and heating device can be the resistance wire heating, and electromagnetic heating and infrared heating's arbitrary one, and the preferred resistance wire heating that has higher efficiency of this embodiment.
The upper cover 4 is provided with a vacuum-pumping system 5 and an exhaust device 6, the vacuum-pumping system 5 is used for pumping air in the furnace, an oxygen-free environment is created, and the plant fiber can be prevented from burning into ash in the carbonization process; the exhaust device 6 can exhaust the gas generated in the reaction in time. The preferred exhaust means of this embodiment is a one-way conductance valve.
The carbonizing device provided by the embodiment is used for processing plant fiber raw materials into a biochar material, and the working process is as follows: firstly, a fiber block 7 formed by compressing plant fibers is placed in a cavity of a base 3, then an upper cover 4 of a carbonization device is covered, a vacuum-pumping system 5 is started, and gases such as oxygen in the carbonization device are discharged. The heater 2 is then activated to carbonize the plant fibers. During the carbonization process, the moisture in the fiber, the white sugar and the dextrin is changed into water vapor, meanwhile, the hydrogen element and the oxygen element in the material are combined to be changed into water vapor, and the gases expand inside the fiber block to form bubbles, and then are discharged out of the furnace through the one-way conduction valve 6. The paraffin is melted and then carbonized, and liquid generated in the carbonization process is discharged from a sewage outlet 8 at the bottom of the base. And after the carbonization is finished, closing the heater, and taking out the carbonized fiber block after cooling. Thus obtaining the biochar product. In the carbonization process, the conditions are as follows: the vacuum rate is more than 85%, the temperature is 150-400 ℃, and the time is 2-24 hours.
Example 2
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting straw fibers, crushing the straw fibers until the diameter is 2mm and the length is 50mm, and then drying the straw fibers until the moisture content of the fibers is 8% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 1kg of paraffin, 1kg of white sugar and 1kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 0.5kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 2 hours under the conditions that the vacuum rate is 85% and the temperature is 150 ℃ to obtain a biochar product.
Example 3
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting reed fibers, crushing the reed fibers until the diameter is 1.5mm and the length is 40mm, and then drying the reed fibers until the water content of the reed fibers is 10% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 1kg of paraffin, 1kg of white sugar and 1kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 0.7kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 6 hours at the temperature of 200 ℃ with the vacuum rate of 85% to obtain the biochar product.
Example 4
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting wood fibers, crushing the wood fibers until the diameter is 1mm and the length is 30mm, and then drying the wood fibers until the water content of the fibers is 15% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 3kg of paraffin, 3kg of white sugar and 3kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 1kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 8 hours under the conditions that the vacuum rate is 90% and the temperature is 250 ℃ to obtain a biochar product.
Example 5
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting straw fibers, crushing the straw fibers until the diameter is 1mm and the length is 20mm, and then drying the straw fibers until the water content of the fibers is 10% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 3kg of paraffin, 3kg of white sugar and 3kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 1kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 10 hours under the conditions that the vacuum rate is 90% and the temperature is 250 ℃ to obtain a biochar product.
Example 6
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting straw fibers, crushing the straw fibers until the diameter is 0.5mm and the length is 20mm, and then drying the straw fibers until the water content of the fibers is 12% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 3kg of paraffin, 3kg of white sugar and 3kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 1.2kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 20 hours under the conditions that the vacuum rate is 90% and the temperature is 300 ℃ to obtain a biochar product.
Example 7
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting straw fibers, crushing the straw fibers until the diameter is 2mm and the length is 10mm, and then drying the straw fibers until the water content of the fibers is 8% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 5kg of paraffin, 5kg of white sugar and 5kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 1.2kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 20 hours under the conditions that the vacuum rate is 95% and the temperature is 400 ℃ to obtain a biochar product.
Example 8
The embodiment provides a method for processing biochar by in-situ evaporation, which comprises the following steps:
s1, selecting straw fibers, crushing the straw fibers until the diameter is 2mm and the length is 10mm, and then drying the straw fibers until the water content of the fibers is 15% for later use;
s2, selecting 100kg of plant fibers treated in the step S1, adding 10kg of paraffin, 10kg of white sugar and 10kg of dextrin, uniformly mixing to obtain fiber blocks, wherein the density of the fiber blocks is 1.2kg/m3;
S3, adding the fiber block prepared in the step S2 into the in-situ evaporation carbonization device described in the embodiment 1, and carbonizing for 24 hours under the conditions that the vacuum rate is 100% and the temperature is 400 ℃ to obtain a biochar product.
Comparative example 1
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S1, the water content of the plant fiber is 5%.
Comparative example 2
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S1, the water content of the plant fiber is 20%.
Comparative example 3
This comparative example provides a method for preparing biochar by an in situ evaporation process, with reference to the procedure of example 5, except that: in step S2, no paraffin was added.
Comparative example 4
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S2, white sugar and dextrin are not added.
Comparative example 5
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: the fiber cake density in step S2 was 0.3kg/m3。
Comparative example 6
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: the fiber cake density in step S2 was 1.5kg/m3。
Comparative example 7
This comparative example provides a method for preparing biochar by an in situ evaporation process, with reference to the procedure of example 5, except that: the vacuum rate of the carbonizing device in step S3 was 80%.
Comparative example 8
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S3, the carbonization time was 1 hour.
Comparative example 9
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S3, the carbonization time was 30 hours.
Comparative example 10
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S3, the carbonization temperature is 100 ℃.
Comparative example 11
This comparative example provides a method for in situ evaporative processing of biochar, with reference to the procedure of example 5, differing from example 5 in that: in step S3, the carbonization temperature was 500 ℃.
The properties of biochar prepared in examples 2 to 8 and comparative examples 1 to 11 are shown in table 1.
TABLE 1
According to the analysis of the comparative examples 1 and 2, the adsorption performance and strength of the biochar prepared by the comparative examples 1 and 2 are lower than those of the biochar prepared by the examples. The reason is that when the water content of the plant fiber is too low, less water vapor is generated in the carbonization process, so that fewer bubbles are generated in the fiber, the number of holes of the biochar product is reduced, and the adsorption performance is influenced; when the moisture content of the plant fiber is too high, more water vapor is generated in the carbonization process, the carbonization progress is influenced, the carbonization is insufficient, and the adsorption performance of the biological carbon is influenced.
The adsorption performance and strength of the biochar prepared in comparative example 3 and comparative example 4 are lower than those of the biochar prepared in the examples. The reason is that in the carbonization process of the plant fiber, the paraffin is melted and then carbonized, and the paraffin is melted and discharged to form a large number of holes, so that the aperture of the biochar can be increased, and the adsorption performance is improved; after the white sugar is carbonized, the ion adsorption capacity of the product can be improved, and after the dextrin is carbonized, the adsorption capacity can be improved, and the strength of the biochar can be increased.
According to analysis of comparative example 5 and comparative example 6, the biochar prepared in comparative example 5 has good adsorption performance, but has too low strength, is easy to break in the production and use processes, and cannot effectively play the role of the biochar; in comparative example 6, the density of the plant fiber block is too high, so that the prepared charcoal has fewer pores, and the adsorption performance is influenced.
Analysis of comparative examples 7-11 shows that the adsorption performance and strength of the biochar prepared in comparative examples 7-11 are lower than those of the biochar prepared in the examples. The reason is that in the carbonization treatment process, the carbonization treatment is influenced by various factors, and the vacuum rate, the carbonization time and the carbonization temperature of the carbonization device can influence the performance of the biochar. If the vacuum rate of the carbonization device is not enough, oxygen remains in the carbonization device, which can cause the fiber block to burn in the carbonization process and influence the adsorption performance and strength of the biochar product. If the carbonization treatment temperature is too high and the time is too long, the temperature difference in the carbonization furnace is large, and the phenomenon of uneven carbonization is caused; if the temperature and time of the carbonization treatment are insufficient, the vegetable fiber blocks are insufficiently carbonized, and the effect of the biochar product is influenced.
It should be understood that the above examples are only for clearly illustrating the technical solutions of the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.